1 /*------------------------------------------------------------------------- 2 * main()3 * postmaster.c 4 * This program acts as a clearing house for requests to the 5 * POSTGRES system. Frontend programs send a startup message 6 * to the Postmaster and the postmaster uses the info in the 7 * message to setup a backend process. 8 * 9 * The postmaster also manages system-wide operations such as 10 * startup and shutdown. The postmaster itself doesn't do those 11 * operations, mind you --- it just forks off a subprocess to do them 12 * at the right times. It also takes care of resetting the system 13 * if a backend crashes. 14 * 15 * The postmaster process creates the shared memory and semaphore 16 * pools during startup, but as a rule does not touch them itself. 17 * In particular, it is not a member of the PGPROC array of backends 18 * and so it cannot participate in lock-manager operations. Keeping 19 * the postmaster away from shared memory operations makes it simpler 20 * and more reliable. The postmaster is almost always able to recover 21 * from crashes of individual backends by resetting shared memory; 22 * if it did much with shared memory then it would be prone to crashing 23 * along with the backends. 24 * 25 * When a request message is received, we now fork() immediately. 26 * The child process performs authentication of the request, and 27 * then becomes a backend if successful. This allows the auth code 28 * to be written in a simple single-threaded style (as opposed to the 29 * crufty "poor man's multitasking" code that used to be needed). 30 * More importantly, it ensures that blockages in non-multithreaded 31 * libraries like SSL or PAM cannot cause denial of service to other 32 * clients. 33 * 34 * 35 * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group 36 * Portions Copyright (c) 1994, Regents of the University of California 37 * 38 * 39 * IDENTIFICATION 40 * src/backend/postmaster/postmaster.c 41 * 42 * NOTES 43 * 44 * Initialization: 45 * The Postmaster sets up shared memory data structures 46 * for the backends. 47 * 48 * Synchronization: 49 * The Postmaster shares memory with the backends but should avoid 50 * touching shared memory, so as not to become stuck if a crashing 51 * backend screws up locks or shared memory. Likewise, the Postmaster 52 * should never block on messages from frontend clients. 53 * 54 * Garbage Collection: 55 * The Postmaster cleans up after backends if they have an emergency 56 * exit and/or core dump. 57 * 58 * Error Reporting: 59 * Use write_stderr() only for reporting "interactive" errors 60 * (essentially, bogus arguments on the command line). Once the 61 * postmaster is launched, use ereport(). 62 * 63 *------------------------------------------------------------------------- 64 */ 65 66 #include "postgres.h" 67 68 #include <unistd.h> 69 #include <signal.h> 70 #include <time.h> 71 #include <sys/wait.h> 72 #include <ctype.h> 73 #include <sys/stat.h> 74 #include <sys/socket.h> 75 #include <fcntl.h> 76 #include <sys/param.h> 77 #include <netdb.h> 78 #include <limits.h> 79 80 #ifdef HAVE_SYS_SELECT_H 81 #include <sys/select.h> 82 #endif 83 84 #ifdef USE_BONJOUR 85 #include <dns_sd.h> 86 #endif 87 88 #ifdef USE_SYSTEMD 89 #include <systemd/sd-daemon.h> 90 #endif 91 92 #ifdef HAVE_PTHREAD_IS_THREADED_NP 93 #include <pthread.h> 94 #endif 95 96 #include "access/transam.h" 97 #include "access/xlog.h" 98 #include "bootstrap/bootstrap.h" 99 #include "catalog/pg_control.h" 100 #include "common/file_perm.h" 101 #include "common/ip.h" 102 #include "lib/ilist.h" 103 #include "libpq/auth.h" 104 #include "libpq/libpq.h" 105 #include "libpq/pqformat.h" 106 #include "libpq/pqsignal.h" 107 #include "miscadmin.h" 108 #include "pg_getopt.h" 109 #include "pgstat.h" 110 #include "port/pg_bswap.h" 111 #include "postmaster/autovacuum.h" 112 #include "postmaster/bgworker_internals.h" 113 #include "postmaster/fork_process.h" 114 #include "postmaster/pgarch.h" 115 #include "postmaster/postmaster.h" 116 #include "postmaster/syslogger.h" 117 #include "replication/logicallauncher.h" 118 #include "replication/walsender.h" 119 #include "storage/fd.h" 120 #include "storage/ipc.h" 121 #include "storage/pg_shmem.h" 122 #include "storage/pmsignal.h" 123 #include "storage/proc.h" 124 #include "tcop/tcopprot.h" 125 #include "utils/builtins.h" 126 #include "utils/datetime.h" 127 #include "utils/dynamic_loader.h" 128 #include "utils/memutils.h" 129 #include "utils/pidfile.h" 130 #include "utils/ps_status.h" 131 #include "utils/timeout.h" 132 #include "utils/varlena.h" 133 134 #ifdef EXEC_BACKEND 135 #include "storage/spin.h" 136 #endif 137 138 139 /* 140 * Possible types of a backend. Beyond being the possible bkend_type values in 141 * struct bkend, these are OR-able request flag bits for SignalSomeChildren() 142 * and CountChildren(). 143 */ 144 #define BACKEND_TYPE_NORMAL 0x0001 /* normal backend */ 145 #define BACKEND_TYPE_AUTOVAC 0x0002 /* autovacuum worker process */ 146 #define BACKEND_TYPE_WALSND 0x0004 /* walsender process */ 147 #define BACKEND_TYPE_BGWORKER 0x0008 /* bgworker process */ 148 #define BACKEND_TYPE_ALL 0x000F /* OR of all the above */ 149 150 /* 151 * List of active backends (or child processes anyway; we don't actually 152 * know whether a given child has become a backend or is still in the 153 * authorization phase). This is used mainly to keep track of how many 154 * children we have and send them appropriate signals when necessary. 155 * 156 * "Special" children such as the startup, bgwriter and autovacuum launcher 157 * tasks are not in this list. Autovacuum worker and walsender are in it. 158 * Also, "dead_end" children are in it: these are children launched just for 159 * the purpose of sending a friendly rejection message to a would-be client. 160 * We must track them because they are attached to shared memory, but we know 161 * they will never become live backends. dead_end children are not assigned a 162 * PMChildSlot. 163 * 164 * Background workers are in this list, too. 165 */ 166 typedef struct bkend 167 { 168 pid_t pid; /* process id of backend */ 169 int32 cancel_key; /* cancel key for cancels for this backend */ 170 int child_slot; /* PMChildSlot for this backend, if any */ 171 172 /* 173 * Flavor of backend or auxiliary process. Note that BACKEND_TYPE_WALSND 174 * backends initially announce themselves as BACKEND_TYPE_NORMAL, so if 175 * bkend_type is normal, you should check for a recent transition. 176 */ 177 int bkend_type; 178 bool dead_end; /* is it going to send an error and quit? */ 179 bool bgworker_notify; /* gets bgworker start/stop notifications */ 180 dlist_node elem; /* list link in BackendList */ 181 } Backend; 182 183 static dlist_head BackendList = DLIST_STATIC_INIT(BackendList); 184 185 #ifdef EXEC_BACKEND 186 static Backend *ShmemBackendArray; 187 #endif 188 189 BackgroundWorker *MyBgworkerEntry = NULL; 190 191 192 193 /* The socket number we are listening for connections on */ 194 int PostPortNumber; 195 196 /* The directory names for Unix socket(s) */ 197 char *Unix_socket_directories; 198 199 /* The TCP listen address(es) */ 200 char *ListenAddresses; 201 202 /* 203 * ReservedBackends is the number of backends reserved for superuser use. 204 * This number is taken out of the pool size given by MaxConnections so 205 * number of backend slots available to non-superusers is 206 * (MaxConnections - ReservedBackends). Note what this really means is 207 * "if there are <= ReservedBackends connections available, only superusers 208 * can make new connections" --- pre-existing superuser connections don't 209 * count against the limit. 210 */ 211 int ReservedBackends; 212 213 /* The socket(s) we're listening to. */ 214 #define MAXLISTEN 64 215 static pgsocket ListenSocket[MAXLISTEN]; 216 217 /* 218 * Set by the -o option 219 */ 220 static char ExtraOptions[MAXPGPATH]; 221 222 /* 223 * These globals control the behavior of the postmaster in case some 224 * backend dumps core. Normally, it kills all peers of the dead backend 225 * and reinitializes shared memory. By specifying -s or -n, we can have 226 * the postmaster stop (rather than kill) peers and not reinitialize 227 * shared data structures. (Reinit is currently dead code, though.) 228 */ 229 static bool Reinit = true; 230 static int SendStop = false; 231 232 /* still more option variables */ 233 bool EnableSSL = false; 234 235 int PreAuthDelay = 0; 236 int AuthenticationTimeout = 60; 237 238 bool log_hostname; /* for ps display and logging */ 239 bool Log_connections = false; 240 bool Db_user_namespace = false; 241 242 bool enable_bonjour = false; 243 char *bonjour_name; 244 bool restart_after_crash = true; 245 246 /* PIDs of special child processes; 0 when not running */ 247 static pid_t StartupPID = 0, 248 BgWriterPID = 0, 249 CheckpointerPID = 0, 250 WalWriterPID = 0, 251 WalReceiverPID = 0, 252 AutoVacPID = 0, 253 PgArchPID = 0, 254 PgStatPID = 0, 255 SysLoggerPID = 0; 256 257 /* Startup process's status */ 258 typedef enum 259 { 260 STARTUP_NOT_RUNNING, 261 STARTUP_RUNNING, 262 STARTUP_SIGNALED, /* we sent it a SIGQUIT or SIGKILL */ 263 STARTUP_CRASHED 264 } StartupStatusEnum; 265 266 static StartupStatusEnum StartupStatus = STARTUP_NOT_RUNNING; 267 268 /* Startup/shutdown state */ 269 #define NoShutdown 0 270 #define SmartShutdown 1 271 #define FastShutdown 2 272 #define ImmediateShutdown 3 273 274 static int Shutdown = NoShutdown; 275 276 static bool FatalError = false; /* T if recovering from backend crash */ 277 278 /* 279 * We use a simple state machine to control startup, shutdown, and 280 * crash recovery (which is rather like shutdown followed by startup). 281 * 282 * After doing all the postmaster initialization work, we enter PM_STARTUP 283 * state and the startup process is launched. The startup process begins by 284 * reading the control file and other preliminary initialization steps. 285 * In a normal startup, or after crash recovery, the startup process exits 286 * with exit code 0 and we switch to PM_RUN state. However, archive recovery 287 * is handled specially since it takes much longer and we would like to support 288 * hot standby during archive recovery. 289 * 290 * When the startup process is ready to start archive recovery, it signals the 291 * postmaster, and we switch to PM_RECOVERY state. The background writer and 292 * checkpointer are launched, while the startup process continues applying WAL. 293 * If Hot Standby is enabled, then, after reaching a consistent point in WAL 294 * redo, startup process signals us again, and we switch to PM_HOT_STANDBY 295 * state and begin accepting connections to perform read-only queries. When 296 * archive recovery is finished, the startup process exits with exit code 0 297 * and we switch to PM_RUN state. 298 * 299 * Normal child backends can only be launched when we are in PM_RUN or 300 * PM_HOT_STANDBY state. (connsAllowed can also restrict launching.) 301 * In other states we handle connection requests by launching "dead_end" 302 * child processes, which will simply send the client an error message and 303 * quit. (We track these in the BackendList so that we can know when they 304 * are all gone; this is important because they're still connected to shared 305 * memory, and would interfere with an attempt to destroy the shmem segment, 306 * possibly leading to SHMALL failure when we try to make a new one.) 307 * In PM_WAIT_DEAD_END state we are waiting for all the dead_end children 308 * to drain out of the system, and therefore stop accepting connection 309 * requests at all until the last existing child has quit (which hopefully 310 * will not be very long). 311 * 312 * Notice that this state variable does not distinguish *why* we entered 313 * states later than PM_RUN --- Shutdown and FatalError must be consulted 314 * to find that out. FatalError is never true in PM_RECOVERY, PM_HOT_STANDBY, 315 * or PM_RUN states, nor in PM_SHUTDOWN states (because we don't enter those 316 * states when trying to recover from a crash). It can be true in PM_STARTUP 317 * state, because we don't clear it until we've successfully started WAL redo. 318 */ 319 typedef enum 320 { 321 PM_INIT, /* postmaster starting */ 322 PM_STARTUP, /* waiting for startup subprocess */ 323 PM_RECOVERY, /* in archive recovery mode */ 324 PM_HOT_STANDBY, /* in hot standby mode */ 325 PM_RUN, /* normal "database is alive" state */ 326 PM_STOP_BACKENDS, /* need to stop remaining backends */ 327 PM_WAIT_BACKENDS, /* waiting for live backends to exit */ 328 PM_SHUTDOWN, /* waiting for checkpointer to do shutdown 329 * ckpt */ 330 PM_SHUTDOWN_2, /* waiting for archiver and walsenders to 331 * finish */ 332 PM_WAIT_DEAD_END, /* waiting for dead_end children to exit */ 333 PM_NO_CHILDREN /* all important children have exited */ 334 } PMState; 335 336 static PMState pmState = PM_INIT; 337 338 /* 339 * While performing a "smart shutdown", we restrict new connections but stay 340 * in PM_RUN or PM_HOT_STANDBY state until all the client backends are gone. 341 * connsAllowed is a sub-state indicator showing the active restriction. 342 * It is of no interest unless pmState is PM_RUN or PM_HOT_STANDBY. 343 */ 344 typedef enum 345 { 346 ALLOW_ALL_CONNS, /* normal not-shutting-down state */ 347 ALLOW_SUPERUSER_CONNS, /* only superusers can connect */ 348 ALLOW_NO_CONNS /* no new connections allowed, period */ 349 } ConnsAllowedState; 350 351 static ConnsAllowedState connsAllowed = ALLOW_ALL_CONNS; 352 353 /* Start time of SIGKILL timeout during immediate shutdown or child crash */ 354 /* Zero means timeout is not running */ 355 static time_t AbortStartTime = 0; 356 357 /* Length of said timeout */ 358 #define SIGKILL_CHILDREN_AFTER_SECS 5 359 360 static bool ReachedNormalRunning = false; /* T if we've reached PM_RUN */ 361 362 bool ClientAuthInProgress = false; /* T during new-client 363 * authentication */ 364 365 bool redirection_done = false; /* stderr redirected for syslogger? */ 366 367 /* received START_AUTOVAC_LAUNCHER signal */ 368 static volatile sig_atomic_t start_autovac_launcher = false; 369 370 /* the launcher needs to be signalled to communicate some condition */ 371 static volatile bool avlauncher_needs_signal = false; 372 373 /* received START_WALRECEIVER signal */ 374 static volatile sig_atomic_t WalReceiverRequested = false; 375 376 /* set when there's a worker that needs to be started up */ 377 static volatile bool StartWorkerNeeded = true; 378 static volatile bool HaveCrashedWorker = false; 379 380 #ifndef HAVE_STRONG_RANDOM 381 /* 382 * State for assigning cancel keys. 383 * Also, the global MyCancelKey passes the cancel key assigned to a given 384 * backend from the postmaster to that backend (via fork). 385 */ 386 static unsigned int random_seed = 0; 387 static struct timeval random_start_time; 388 #endif 389 390 #ifdef USE_SSL 391 /* Set when and if SSL has been initialized properly */ 392 static bool LoadedSSL = false; 393 #endif 394 395 #ifdef USE_BONJOUR 396 static DNSServiceRef bonjour_sdref = NULL; 397 #endif 398 399 /* 400 * postmaster.c - function prototypes 401 */ 402 static void CloseServerPorts(int status, Datum arg); 403 static void unlink_external_pid_file(int status, Datum arg); 404 static void getInstallationPaths(const char *argv0); 405 static void checkControlFile(void); 406 static Port *ConnCreate(int serverFd); 407 static void ConnFree(Port *port); 408 static void reset_shared(int port); 409 static void SIGHUP_handler(SIGNAL_ARGS); 410 static void pmdie(SIGNAL_ARGS); 411 static void reaper(SIGNAL_ARGS); 412 static void sigusr1_handler(SIGNAL_ARGS); 413 static void process_startup_packet_die(SIGNAL_ARGS); 414 static void process_startup_packet_quickdie(SIGNAL_ARGS); 415 static void dummy_handler(SIGNAL_ARGS); 416 static void StartupPacketTimeoutHandler(void); 417 static void CleanupBackend(int pid, int exitstatus); 418 static bool CleanupBackgroundWorker(int pid, int exitstatus); 419 static void HandleChildCrash(int pid, int exitstatus, const char *procname); 420 static void LogChildExit(int lev, const char *procname, 421 int pid, int exitstatus); 422 static void PostmasterStateMachine(void); 423 static void BackendInitialize(Port *port); 424 static void BackendRun(Port *port) pg_attribute_noreturn(); 425 static void ExitPostmaster(int status) pg_attribute_noreturn(); 426 static int ServerLoop(void); 427 static int BackendStartup(Port *port); 428 static int ProcessStartupPacket(Port *port, bool SSLdone); 429 static void SendNegotiateProtocolVersion(List *unrecognized_protocol_options); 430 static void processCancelRequest(Port *port, void *pkt); 431 static int initMasks(fd_set *rmask); 432 static void report_fork_failure_to_client(Port *port, int errnum); 433 static CAC_state canAcceptConnections(int backend_type); 434 static bool RandomCancelKey(int32 *cancel_key); 435 static void signal_child(pid_t pid, int signal); 436 static bool SignalSomeChildren(int signal, int targets); 437 static void TerminateChildren(int signal); 438 439 #define SignalChildren(sig) SignalSomeChildren(sig, BACKEND_TYPE_ALL) 440 441 static int CountChildren(int target); 442 static bool assign_backendlist_entry(RegisteredBgWorker *rw); 443 static void maybe_start_bgworkers(void); 444 static bool CreateOptsFile(int argc, char *argv[], char *fullprogname); 445 static pid_t StartChildProcess(AuxProcType type); 446 static void StartAutovacuumWorker(void); 447 static void MaybeStartWalReceiver(void); 448 static void InitPostmasterDeathWatchHandle(void); 449 450 /* 451 * Archiver is allowed to start up at the current postmaster state? 452 * 453 * If WAL archiving is enabled always, we are allowed to start archiver 454 * even during recovery. 455 */ 456 #define PgArchStartupAllowed() \ 457 ((XLogArchivingActive() && pmState == PM_RUN) || \ 458 (XLogArchivingAlways() && \ 459 (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY))) 460 461 #ifdef EXEC_BACKEND 462 463 #ifdef WIN32 464 #define WNOHANG 0 /* ignored, so any integer value will do */ 465 466 static pid_t waitpid(pid_t pid, int *exitstatus, int options); 467 static void WINAPI pgwin32_deadchild_callback(PVOID lpParameter, BOOLEAN TimerOrWaitFired); 468 469 static HANDLE win32ChildQueue; 470 471 typedef struct 472 { 473 HANDLE waitHandle; 474 HANDLE procHandle; 475 DWORD procId; 476 } win32_deadchild_waitinfo; 477 #endif /* WIN32 */ 478 479 static pid_t backend_forkexec(Port *port); 480 static pid_t internal_forkexec(int argc, char *argv[], Port *port); 481 482 /* Type for a socket that can be inherited to a client process */ 483 #ifdef WIN32 484 typedef struct 485 { 486 SOCKET origsocket; /* Original socket value, or PGINVALID_SOCKET 487 * if not a socket */ 488 WSAPROTOCOL_INFO wsainfo; 489 } InheritableSocket; 490 #else 491 typedef int InheritableSocket; 492 #endif 493 494 /* 495 * Structure contains all variables passed to exec:ed backends 496 */ 497 typedef struct 498 { 499 Port port; 500 InheritableSocket portsocket; 501 char DataDir[MAXPGPATH]; 502 pgsocket ListenSocket[MAXLISTEN]; 503 int32 MyCancelKey; 504 int MyPMChildSlot; 505 #ifndef WIN32 506 unsigned long UsedShmemSegID; 507 #else 508 void *ShmemProtectiveRegion; 509 HANDLE UsedShmemSegID; 510 #endif 511 void *UsedShmemSegAddr; 512 slock_t *ShmemLock; 513 VariableCache ShmemVariableCache; 514 Backend *ShmemBackendArray; 515 #ifndef HAVE_SPINLOCKS 516 PGSemaphore *SpinlockSemaArray; 517 #endif 518 int NamedLWLockTrancheRequests; 519 NamedLWLockTranche *NamedLWLockTrancheArray; 520 LWLockPadded *MainLWLockArray; 521 slock_t *ProcStructLock; 522 PROC_HDR *ProcGlobal; 523 PGPROC *AuxiliaryProcs; 524 PGPROC *PreparedXactProcs; 525 PMSignalData *PMSignalState; 526 InheritableSocket pgStatSock; 527 pid_t PostmasterPid; 528 TimestampTz PgStartTime; 529 TimestampTz PgReloadTime; 530 pg_time_t first_syslogger_file_time; 531 bool redirection_done; 532 bool IsBinaryUpgrade; 533 int max_safe_fds; 534 int MaxBackends; 535 #ifdef WIN32 536 HANDLE PostmasterHandle; 537 HANDLE initial_signal_pipe; 538 HANDLE syslogPipe[2]; 539 #else 540 int postmaster_alive_fds[2]; 541 int syslogPipe[2]; 542 #endif 543 char my_exec_path[MAXPGPATH]; 544 char pkglib_path[MAXPGPATH]; 545 char ExtraOptions[MAXPGPATH]; 546 } BackendParameters; 547 548 static void read_backend_variables(char *id, Port *port); 549 static void restore_backend_variables(BackendParameters *param, Port *port); 550 551 #ifndef WIN32 552 static bool save_backend_variables(BackendParameters *param, Port *port); 553 #else 554 static bool save_backend_variables(BackendParameters *param, Port *port, 555 HANDLE childProcess, pid_t childPid); 556 #endif 557 558 static void ShmemBackendArrayAdd(Backend *bn); 559 static void ShmemBackendArrayRemove(Backend *bn); 560 #endif /* EXEC_BACKEND */ 561 562 #define StartupDataBase() StartChildProcess(StartupProcess) 563 #define StartBackgroundWriter() StartChildProcess(BgWriterProcess) 564 #define StartCheckpointer() StartChildProcess(CheckpointerProcess) 565 #define StartWalWriter() StartChildProcess(WalWriterProcess) 566 #define StartWalReceiver() StartChildProcess(WalReceiverProcess) 567 568 /* Macros to check exit status of a child process */ 569 #define EXIT_STATUS_0(st) ((st) == 0) 570 #define EXIT_STATUS_1(st) (WIFEXITED(st) && WEXITSTATUS(st) == 1) 571 #define EXIT_STATUS_3(st) (WIFEXITED(st) && WEXITSTATUS(st) == 3) 572 573 #ifndef WIN32 574 /* 575 * File descriptors for pipe used to monitor if postmaster is alive. 576 * First is POSTMASTER_FD_WATCH, second is POSTMASTER_FD_OWN. 577 */ 578 int postmaster_alive_fds[2] = {-1, -1}; 579 #else 580 /* Process handle of postmaster used for the same purpose on Windows */ 581 HANDLE PostmasterHandle; 582 #endif 583 584 /* 585 * Postmaster main entry point 586 */ 587 void 588 PostmasterMain(int argc, char *argv[]) 589 { 590 int opt; 591 int status; 592 char *userDoption = NULL; 593 bool listen_addr_saved = false; 594 int i; 595 char *output_config_variable = NULL; 596 597 MyProcPid = PostmasterPid = getpid(); 598 599 MyStartTime = time(NULL); 600 601 IsPostmasterEnvironment = true; 602 603 /* 604 * We should not be creating any files or directories before we check the 605 * data directory (see checkDataDir()), but just in case set the umask to 606 * the most restrictive (owner-only) permissions. 607 * 608 * checkDataDir() will reset the umask based on the data directory 609 * permissions. 610 */ 611 umask(PG_MODE_MASK_OWNER); 612 613 /* 614 * Initialize random(3) so we don't get the same values in every run. 615 * 616 * Note: the seed is pretty predictable from externally-visible facts such 617 * as postmaster start time, so avoid using random() for security-critical 618 * random values during postmaster startup. At the time of first 619 * connection, PostmasterRandom will select a hopefully-more-random seed. 620 */ 621 srandom((unsigned int) (MyProcPid ^ MyStartTime)); 622 623 /* 624 * By default, palloc() requests in the postmaster will be allocated in 625 * the PostmasterContext, which is space that can be recycled by backends. 626 * Allocated data that needs to be available to backends should be 627 * allocated in TopMemoryContext. 628 */ 629 PostmasterContext = AllocSetContextCreate(TopMemoryContext, 630 "Postmaster", 631 ALLOCSET_DEFAULT_SIZES); 632 MemoryContextSwitchTo(PostmasterContext); 633 634 /* Initialize paths to installation files */ 635 getInstallationPaths(argv[0]); 636 637 /* 638 * Set up signal handlers for the postmaster process. 639 * 640 * In the postmaster, we use pqsignal_pm() rather than pqsignal() (which 641 * is used by all child processes and client processes). That has a 642 * couple of special behaviors: 643 * 644 * 1. Except on Windows, we tell sigaction() to block all signals for the 645 * duration of the signal handler. This is faster than our old approach 646 * of blocking/unblocking explicitly in the signal handler, and it should 647 * also prevent excessive stack consumption if signals arrive quickly. 648 * 649 * 2. We do not set the SA_RESTART flag. This is because signals will be 650 * blocked at all times except when ServerLoop is waiting for something to 651 * happen, and during that window, we want signals to exit the select(2) 652 * wait so that ServerLoop can respond if anything interesting happened. 653 * On some platforms, signals marked SA_RESTART would not cause the 654 * select() wait to end. 655 * 656 * Child processes will generally want SA_RESTART, so pqsignal() sets that 657 * flag. We expect children to set up their own handlers before 658 * unblocking signals. 659 * 660 * CAUTION: when changing this list, check for side-effects on the signal 661 * handling setup of child processes. See tcop/postgres.c, 662 * bootstrap/bootstrap.c, postmaster/bgwriter.c, postmaster/walwriter.c, 663 * postmaster/autovacuum.c, postmaster/pgarch.c, postmaster/pgstat.c, 664 * postmaster/syslogger.c, postmaster/bgworker.c and 665 * postmaster/checkpointer.c. 666 */ 667 pqinitmask(); 668 PG_SETMASK(&BlockSig); 669 670 pqsignal_pm(SIGHUP, SIGHUP_handler); /* reread config file and have 671 * children do same */ 672 pqsignal_pm(SIGINT, pmdie); /* send SIGTERM and shut down */ 673 pqsignal_pm(SIGQUIT, pmdie); /* send SIGQUIT and die */ 674 pqsignal_pm(SIGTERM, pmdie); /* wait for children and shut down */ 675 pqsignal_pm(SIGALRM, SIG_IGN); /* ignored */ 676 pqsignal_pm(SIGPIPE, SIG_IGN); /* ignored */ 677 pqsignal_pm(SIGUSR1, sigusr1_handler); /* message from child process */ 678 pqsignal_pm(SIGUSR2, dummy_handler); /* unused, reserve for children */ 679 pqsignal_pm(SIGCHLD, reaper); /* handle child termination */ 680 pqsignal_pm(SIGTTIN, SIG_IGN); /* ignored */ 681 pqsignal_pm(SIGTTOU, SIG_IGN); /* ignored */ 682 /* ignore SIGXFSZ, so that ulimit violations work like disk full */ 683 #ifdef SIGXFSZ 684 pqsignal_pm(SIGXFSZ, SIG_IGN); /* ignored */ 685 #endif 686 687 /* 688 * Options setup 689 */ 690 InitializeGUCOptions(); 691 692 opterr = 1; 693 694 /* 695 * Parse command-line options. CAUTION: keep this in sync with 696 * tcop/postgres.c (the option sets should not conflict) and with the 697 * common help() function in main/main.c. 698 */ 699 while ((opt = getopt(argc, argv, "B:bc:C:D:d:EeFf:h:ijk:lN:nOo:Pp:r:S:sTt:W:-:")) != -1) 700 { 701 switch (opt) 702 { 703 case 'B': 704 SetConfigOption("shared_buffers", optarg, PGC_POSTMASTER, PGC_S_ARGV); 705 break; 706 707 case 'b': 708 /* Undocumented flag used for binary upgrades */ 709 IsBinaryUpgrade = true; 710 break; 711 712 case 'C': 713 output_config_variable = strdup(optarg); 714 break; 715 716 case 'D': 717 userDoption = strdup(optarg); 718 break; 719 720 case 'd': 721 set_debug_options(atoi(optarg), PGC_POSTMASTER, PGC_S_ARGV); 722 break; 723 724 case 'E': 725 SetConfigOption("log_statement", "all", PGC_POSTMASTER, PGC_S_ARGV); 726 break; 727 728 case 'e': 729 SetConfigOption("datestyle", "euro", PGC_POSTMASTER, PGC_S_ARGV); 730 break; 731 732 case 'F': 733 SetConfigOption("fsync", "false", PGC_POSTMASTER, PGC_S_ARGV); 734 break; 735 736 case 'f': 737 if (!set_plan_disabling_options(optarg, PGC_POSTMASTER, PGC_S_ARGV)) 738 { 739 write_stderr("%s: invalid argument for option -f: \"%s\"\n", 740 progname, optarg); 741 ExitPostmaster(1); 742 } 743 break; 744 745 case 'h': 746 SetConfigOption("listen_addresses", optarg, PGC_POSTMASTER, PGC_S_ARGV); 747 break; 748 749 case 'i': 750 SetConfigOption("listen_addresses", "*", PGC_POSTMASTER, PGC_S_ARGV); 751 break; 752 753 case 'j': 754 /* only used by interactive backend */ 755 break; 756 757 case 'k': 758 SetConfigOption("unix_socket_directories", optarg, PGC_POSTMASTER, PGC_S_ARGV); 759 break; 760 761 case 'l': 762 SetConfigOption("ssl", "true", PGC_POSTMASTER, PGC_S_ARGV); 763 break; 764 765 case 'N': 766 SetConfigOption("max_connections", optarg, PGC_POSTMASTER, PGC_S_ARGV); 767 break; 768 769 case 'n': 770 /* Don't reinit shared mem after abnormal exit */ 771 Reinit = false; 772 break; 773 774 case 'O': 775 SetConfigOption("allow_system_table_mods", "true", PGC_POSTMASTER, PGC_S_ARGV); 776 break; 777 778 case 'o': 779 /* Other options to pass to the backend on the command line */ 780 snprintf(ExtraOptions + strlen(ExtraOptions), 781 sizeof(ExtraOptions) - strlen(ExtraOptions), 782 " %s", optarg); 783 break; 784 785 case 'P': 786 SetConfigOption("ignore_system_indexes", "true", PGC_POSTMASTER, PGC_S_ARGV); 787 break; 788 789 case 'p': 790 SetConfigOption("port", optarg, PGC_POSTMASTER, PGC_S_ARGV); 791 break; 792 793 case 'r': 794 /* only used by single-user backend */ 795 break; 796 797 case 'S': 798 SetConfigOption("work_mem", optarg, PGC_POSTMASTER, PGC_S_ARGV); 799 break; 800 801 case 's': 802 SetConfigOption("log_statement_stats", "true", PGC_POSTMASTER, PGC_S_ARGV); 803 break; 804 805 case 'T': 806 807 /* 808 * In the event that some backend dumps core, send SIGSTOP, 809 * rather than SIGQUIT, to all its peers. This lets the wily 810 * post_hacker collect core dumps from everyone. 811 */ 812 SendStop = true; 813 break; 814 815 case 't': 816 { 817 const char *tmp = get_stats_option_name(optarg); 818 819 if (tmp) 820 { 821 SetConfigOption(tmp, "true", PGC_POSTMASTER, PGC_S_ARGV); 822 } 823 else 824 { 825 write_stderr("%s: invalid argument for option -t: \"%s\"\n", 826 progname, optarg); 827 ExitPostmaster(1); 828 } 829 break; 830 } 831 832 case 'W': 833 SetConfigOption("post_auth_delay", optarg, PGC_POSTMASTER, PGC_S_ARGV); 834 break; 835 836 case 'c': 837 case '-': 838 { 839 char *name, 840 *value; 841 842 ParseLongOption(optarg, &name, &value); 843 if (!value) 844 { 845 if (opt == '-') 846 ereport(ERROR, 847 (errcode(ERRCODE_SYNTAX_ERROR), 848 errmsg("--%s requires a value", 849 optarg))); 850 else 851 ereport(ERROR, 852 (errcode(ERRCODE_SYNTAX_ERROR), 853 errmsg("-c %s requires a value", 854 optarg))); 855 } 856 857 SetConfigOption(name, value, PGC_POSTMASTER, PGC_S_ARGV); 858 free(name); 859 if (value) 860 free(value); 861 break; 862 } 863 864 default: 865 write_stderr("Try \"%s --help\" for more information.\n", 866 progname); 867 ExitPostmaster(1); 868 } 869 } 870 871 /* 872 * Postmaster accepts no non-option switch arguments. 873 */ 874 if (optind < argc) 875 { 876 write_stderr("%s: invalid argument: \"%s\"\n", 877 progname, argv[optind]); 878 write_stderr("Try \"%s --help\" for more information.\n", 879 progname); 880 ExitPostmaster(1); 881 } 882 883 /* 884 * Locate the proper configuration files and data directory, and read 885 * postgresql.conf for the first time. 886 */ 887 if (!SelectConfigFiles(userDoption, progname)) 888 ExitPostmaster(2); 889 890 if (output_config_variable != NULL) 891 { 892 /* 893 * "-C guc" was specified, so print GUC's value and exit. No extra 894 * permission check is needed because the user is reading inside the 895 * data dir. 896 */ 897 const char *config_val = GetConfigOption(output_config_variable, 898 false, false); 899 900 puts(config_val ? config_val : ""); 901 ExitPostmaster(0); 902 } 903 904 /* Verify that DataDir looks reasonable */ 905 checkDataDir(); 906 907 /* Check that pg_control exists */ 908 checkControlFile(); 909 910 /* And switch working directory into it */ 911 ChangeToDataDir(); 912 913 /* 914 * Check for invalid combinations of GUC settings. 915 */ 916 if (ReservedBackends + max_wal_senders >= MaxConnections) 917 { 918 write_stderr("%s: superuser_reserved_connections (%d) plus max_wal_senders (%d) must be less than max_connections (%d)\n", 919 progname, 920 ReservedBackends, max_wal_senders, MaxConnections); 921 ExitPostmaster(1); 922 } 923 if (XLogArchiveMode > ARCHIVE_MODE_OFF && wal_level == WAL_LEVEL_MINIMAL) 924 ereport(ERROR, 925 (errmsg("WAL archival cannot be enabled when wal_level is \"minimal\""))); 926 if (max_wal_senders > 0 && wal_level == WAL_LEVEL_MINIMAL) 927 ereport(ERROR, 928 (errmsg("WAL streaming (max_wal_senders > 0) requires wal_level \"replica\" or \"logical\""))); 929 930 /* 931 * Other one-time internal sanity checks can go here, if they are fast. 932 * (Put any slow processing further down, after postmaster.pid creation.) 933 */ 934 if (!CheckDateTokenTables()) 935 { 936 write_stderr("%s: invalid datetoken tables, please fix\n", progname); 937 ExitPostmaster(1); 938 } 939 940 /* 941 * Now that we are done processing the postmaster arguments, reset 942 * getopt(3) library so that it will work correctly in subprocesses. 943 */ 944 optind = 1; 945 #ifdef HAVE_INT_OPTRESET 946 optreset = 1; /* some systems need this too */ 947 #endif 948 949 /* For debugging: display postmaster environment */ 950 { 951 extern char **environ; 952 char **p; 953 954 ereport(DEBUG3, 955 (errmsg_internal("%s: PostmasterMain: initial environment dump:", 956 progname))); 957 ereport(DEBUG3, 958 (errmsg_internal("-----------------------------------------"))); 959 for (p = environ; *p; ++p) 960 ereport(DEBUG3, 961 (errmsg_internal("\t%s", *p))); 962 ereport(DEBUG3, 963 (errmsg_internal("-----------------------------------------"))); 964 } 965 966 /* 967 * Create lockfile for data directory. 968 * 969 * We want to do this before we try to grab the input sockets, because the 970 * data directory interlock is more reliable than the socket-file 971 * interlock (thanks to whoever decided to put socket files in /tmp :-(). 972 * For the same reason, it's best to grab the TCP socket(s) before the 973 * Unix socket(s). 974 * 975 * Also note that this internally sets up the on_proc_exit function that 976 * is responsible for removing both data directory and socket lockfiles; 977 * so it must happen before opening sockets so that at exit, the socket 978 * lockfiles go away after CloseServerPorts runs. 979 */ 980 CreateDataDirLockFile(true); 981 982 /* 983 * Read the control file (for error checking and config info). 984 * 985 * Since we verify the control file's CRC, this has a useful side effect 986 * on machines where we need a run-time test for CRC support instructions. 987 * The postmaster will do the test once at startup, and then its child 988 * processes will inherit the correct function pointer and not need to 989 * repeat the test. 990 */ 991 LocalProcessControlFile(false); 992 993 /* 994 * Initialize SSL library, if specified. 995 */ 996 #ifdef USE_SSL 997 if (EnableSSL) 998 { 999 (void) secure_initialize(true); 1000 LoadedSSL = true; 1001 } 1002 #endif 1003 1004 /* 1005 * Register the apply launcher. Since it registers a background worker, 1006 * it needs to be called before InitializeMaxBackends(), and it's probably 1007 * a good idea to call it before any modules had chance to take the 1008 * background worker slots. 1009 */ 1010 ApplyLauncherRegister(); 1011 1012 /* 1013 * process any libraries that should be preloaded at postmaster start 1014 */ 1015 process_shared_preload_libraries(); 1016 1017 /* 1018 * Now that loadable modules have had their chance to register background 1019 * workers, calculate MaxBackends. 1020 */ 1021 InitializeMaxBackends(); 1022 1023 /* 1024 * Establish input sockets. 1025 * 1026 * First, mark them all closed, and set up an on_proc_exit function that's 1027 * charged with closing the sockets again at postmaster shutdown. 1028 */ 1029 for (i = 0; i < MAXLISTEN; i++) 1030 ListenSocket[i] = PGINVALID_SOCKET; 1031 1032 on_proc_exit(CloseServerPorts, 0); 1033 1034 if (ListenAddresses) 1035 { 1036 char *rawstring; 1037 List *elemlist; 1038 ListCell *l; 1039 int success = 0; 1040 1041 /* Need a modifiable copy of ListenAddresses */ 1042 rawstring = pstrdup(ListenAddresses); 1043 1044 /* Parse string into list of hostnames */ 1045 if (!SplitIdentifierString(rawstring, ',', &elemlist)) 1046 { 1047 /* syntax error in list */ 1048 ereport(FATAL, 1049 (errcode(ERRCODE_INVALID_PARAMETER_VALUE), 1050 errmsg("invalid list syntax in parameter \"%s\"", 1051 "listen_addresses"))); 1052 } 1053 1054 foreach(l, elemlist) 1055 { 1056 char *curhost = (char *) lfirst(l); 1057 1058 if (strcmp(curhost, "*") == 0) 1059 status = StreamServerPort(AF_UNSPEC, NULL, 1060 (unsigned short) PostPortNumber, 1061 NULL, 1062 ListenSocket, MAXLISTEN); 1063 else 1064 status = StreamServerPort(AF_UNSPEC, curhost, 1065 (unsigned short) PostPortNumber, 1066 NULL, 1067 ListenSocket, MAXLISTEN); 1068 1069 if (status == STATUS_OK) 1070 { 1071 success++; 1072 /* record the first successful host addr in lockfile */ 1073 if (!listen_addr_saved) 1074 { 1075 AddToDataDirLockFile(LOCK_FILE_LINE_LISTEN_ADDR, curhost); 1076 listen_addr_saved = true; 1077 } 1078 } 1079 else 1080 ereport(WARNING, 1081 (errmsg("could not create listen socket for \"%s\"", 1082 curhost))); 1083 } 1084 1085 if (!success && elemlist != NIL) 1086 ereport(FATAL, 1087 (errmsg("could not create any TCP/IP sockets"))); 1088 1089 list_free(elemlist); 1090 pfree(rawstring); 1091 } 1092 1093 #ifdef USE_BONJOUR 1094 /* Register for Bonjour only if we opened TCP socket(s) */ 1095 if (enable_bonjour && ListenSocket[0] != PGINVALID_SOCKET) 1096 { 1097 DNSServiceErrorType err; 1098 1099 /* 1100 * We pass 0 for interface_index, which will result in registering on 1101 * all "applicable" interfaces. It's not entirely clear from the 1102 * DNS-SD docs whether this would be appropriate if we have bound to 1103 * just a subset of the available network interfaces. 1104 */ 1105 err = DNSServiceRegister(&bonjour_sdref, 1106 0, 1107 0, 1108 bonjour_name, 1109 "_postgresql._tcp.", 1110 NULL, 1111 NULL, 1112 pg_hton16(PostPortNumber), 1113 0, 1114 NULL, 1115 NULL, 1116 NULL); 1117 if (err != kDNSServiceErr_NoError) 1118 elog(LOG, "DNSServiceRegister() failed: error code %ld", 1119 (long) err); 1120 1121 /* 1122 * We don't bother to read the mDNS daemon's reply, and we expect that 1123 * it will automatically terminate our registration when the socket is 1124 * closed at postmaster termination. So there's nothing more to be 1125 * done here. However, the bonjour_sdref is kept around so that 1126 * forked children can close their copies of the socket. 1127 */ 1128 } 1129 #endif 1130 1131 #ifdef HAVE_UNIX_SOCKETS 1132 if (Unix_socket_directories) 1133 { 1134 char *rawstring; 1135 List *elemlist; 1136 ListCell *l; 1137 int success = 0; 1138 1139 /* Need a modifiable copy of Unix_socket_directories */ 1140 rawstring = pstrdup(Unix_socket_directories); 1141 1142 /* Parse string into list of directories */ 1143 if (!SplitDirectoriesString(rawstring, ',', &elemlist)) 1144 { 1145 /* syntax error in list */ 1146 ereport(FATAL, 1147 (errcode(ERRCODE_INVALID_PARAMETER_VALUE), 1148 errmsg("invalid list syntax in parameter \"%s\"", 1149 "unix_socket_directories"))); 1150 } 1151 1152 foreach(l, elemlist) 1153 { 1154 char *socketdir = (char *) lfirst(l); 1155 1156 status = StreamServerPort(AF_UNIX, NULL, 1157 (unsigned short) PostPortNumber, 1158 socketdir, 1159 ListenSocket, MAXLISTEN); 1160 1161 if (status == STATUS_OK) 1162 { 1163 success++; 1164 /* record the first successful Unix socket in lockfile */ 1165 if (success == 1) 1166 AddToDataDirLockFile(LOCK_FILE_LINE_SOCKET_DIR, socketdir); 1167 } 1168 else 1169 ereport(WARNING, 1170 (errmsg("could not create Unix-domain socket in directory \"%s\"", 1171 socketdir))); 1172 } 1173 1174 if (!success && elemlist != NIL) 1175 ereport(FATAL, 1176 (errmsg("could not create any Unix-domain sockets"))); 1177 1178 list_free_deep(elemlist); 1179 pfree(rawstring); 1180 } 1181 #endif 1182 1183 /* 1184 * check that we have some socket to listen on 1185 */ 1186 if (ListenSocket[0] == PGINVALID_SOCKET) 1187 ereport(FATAL, 1188 (errmsg("no socket created for listening"))); 1189 1190 /* 1191 * If no valid TCP ports, write an empty line for listen address, 1192 * indicating the Unix socket must be used. Note that this line is not 1193 * added to the lock file until there is a socket backing it. 1194 */ 1195 if (!listen_addr_saved) 1196 AddToDataDirLockFile(LOCK_FILE_LINE_LISTEN_ADDR, ""); 1197 1198 /* 1199 * Set up shared memory and semaphores. 1200 */ 1201 reset_shared(PostPortNumber); 1202 1203 /* 1204 * Estimate number of openable files. This must happen after setting up 1205 * semaphores, because on some platforms semaphores count as open files. 1206 */ 1207 set_max_safe_fds(); 1208 1209 /* 1210 * Set reference point for stack-depth checking. 1211 */ 1212 set_stack_base(); 1213 1214 /* 1215 * Initialize pipe (or process handle on Windows) that allows children to 1216 * wake up from sleep on postmaster death. 1217 */ 1218 InitPostmasterDeathWatchHandle(); 1219 1220 #ifdef WIN32 1221 1222 /* 1223 * Initialize I/O completion port used to deliver list of dead children. 1224 */ 1225 win32ChildQueue = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 1); 1226 if (win32ChildQueue == NULL) 1227 ereport(FATAL, 1228 (errmsg("could not create I/O completion port for child queue"))); 1229 #endif 1230 1231 /* 1232 * Record postmaster options. We delay this till now to avoid recording 1233 * bogus options (eg, NBuffers too high for available memory). 1234 */ 1235 if (!CreateOptsFile(argc, argv, my_exec_path)) 1236 ExitPostmaster(1); 1237 1238 #ifdef EXEC_BACKEND 1239 /* Write out nondefault GUC settings for child processes to use */ 1240 write_nondefault_variables(PGC_POSTMASTER); 1241 #endif 1242 1243 /* 1244 * Write the external PID file if requested 1245 */ 1246 if (external_pid_file) 1247 { 1248 FILE *fpidfile = fopen(external_pid_file, "w"); 1249 1250 if (fpidfile) 1251 { 1252 fprintf(fpidfile, "%d\n", MyProcPid); 1253 fclose(fpidfile); 1254 1255 /* Make PID file world readable */ 1256 if (chmod(external_pid_file, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) != 0) 1257 write_stderr("%s: could not change permissions of external PID file \"%s\": %s\n", 1258 progname, external_pid_file, strerror(errno)); 1259 } 1260 else 1261 write_stderr("%s: could not write external PID file \"%s\": %s\n", 1262 progname, external_pid_file, strerror(errno)); 1263 1264 on_proc_exit(unlink_external_pid_file, 0); 1265 } 1266 1267 /* 1268 * Remove old temporary files. At this point there can be no other 1269 * Postgres processes running in this directory, so this should be safe. 1270 */ 1271 RemovePgTempFiles(); 1272 1273 /* 1274 * Forcibly remove the files signaling a standby promotion request. 1275 * Otherwise, the existence of those files triggers a promotion too early, 1276 * whether a user wants that or not. 1277 * 1278 * This removal of files is usually unnecessary because they can exist 1279 * only during a few moments during a standby promotion. However there is 1280 * a race condition: if pg_ctl promote is executed and creates the files 1281 * during a promotion, the files can stay around even after the server is 1282 * brought up to new master. Then, if new standby starts by using the 1283 * backup taken from that master, the files can exist at the server 1284 * startup and should be removed in order to avoid an unexpected 1285 * promotion. 1286 * 1287 * Note that promotion signal files need to be removed before the startup 1288 * process is invoked. Because, after that, they can be used by 1289 * postmaster's SIGUSR1 signal handler. 1290 */ 1291 RemovePromoteSignalFiles(); 1292 1293 /* Remove any outdated file holding the current log filenames. */ 1294 if (unlink(LOG_METAINFO_DATAFILE) < 0 && errno != ENOENT) 1295 ereport(LOG, 1296 (errcode_for_file_access(), 1297 errmsg("could not remove file \"%s\": %m", 1298 LOG_METAINFO_DATAFILE))); 1299 1300 /* 1301 * If enabled, start up syslogger collection subprocess 1302 */ 1303 SysLoggerPID = SysLogger_Start(); 1304 1305 /* 1306 * Reset whereToSendOutput from DestDebug (its starting state) to 1307 * DestNone. This stops ereport from sending log messages to stderr unless 1308 * Log_destination permits. We don't do this until the postmaster is 1309 * fully launched, since startup failures may as well be reported to 1310 * stderr. 1311 * 1312 * If we are in fact disabling logging to stderr, first emit a log message 1313 * saying so, to provide a breadcrumb trail for users who may not remember 1314 * that their logging is configured to go somewhere else. 1315 */ 1316 if (!(Log_destination & LOG_DESTINATION_STDERR)) 1317 ereport(LOG, 1318 (errmsg("ending log output to stderr"), 1319 errhint("Future log output will go to log destination \"%s\".", 1320 Log_destination_string))); 1321 1322 whereToSendOutput = DestNone; 1323 1324 /* 1325 * Initialize stats collection subsystem (this does NOT start the 1326 * collector process!) 1327 */ 1328 pgstat_init(); 1329 1330 /* 1331 * Initialize the autovacuum subsystem (again, no process start yet) 1332 */ 1333 autovac_init(); 1334 1335 /* 1336 * Load configuration files for client authentication. 1337 */ 1338 if (!load_hba()) 1339 { 1340 /* 1341 * It makes no sense to continue if we fail to load the HBA file, 1342 * since there is no way to connect to the database in this case. 1343 */ 1344 ereport(FATAL, 1345 (errmsg("could not load pg_hba.conf"))); 1346 } 1347 if (!load_ident()) 1348 { 1349 /* 1350 * We can start up without the IDENT file, although it means that you 1351 * cannot log in using any of the authentication methods that need a 1352 * user name mapping. load_ident() already logged the details of error 1353 * to the log. 1354 */ 1355 } 1356 1357 #ifdef HAVE_PTHREAD_IS_THREADED_NP 1358 1359 /* 1360 * On macOS, libintl replaces setlocale() with a version that calls 1361 * CFLocaleCopyCurrent() when its second argument is "" and every relevant 1362 * environment variable is unset or empty. CFLocaleCopyCurrent() makes 1363 * the process multithreaded. The postmaster calls sigprocmask() and 1364 * calls fork() without an immediate exec(), both of which have undefined 1365 * behavior in a multithreaded program. A multithreaded postmaster is the 1366 * normal case on Windows, which offers neither fork() nor sigprocmask(). 1367 */ 1368 if (pthread_is_threaded_np() != 0) 1369 ereport(FATAL, 1370 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), 1371 errmsg("postmaster became multithreaded during startup"), 1372 errhint("Set the LC_ALL environment variable to a valid locale."))); 1373 #endif 1374 1375 /* 1376 * Remember postmaster startup time 1377 */ 1378 PgStartTime = GetCurrentTimestamp(); 1379 #ifndef HAVE_STRONG_RANDOM 1380 /* RandomCancelKey wants its own copy */ 1381 gettimeofday(&random_start_time, NULL); 1382 #endif 1383 1384 /* 1385 * Report postmaster status in the postmaster.pid file, to allow pg_ctl to 1386 * see what's happening. 1387 */ 1388 AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STARTING); 1389 1390 /* 1391 * We're ready to rock and roll... 1392 */ 1393 StartupPID = StartupDataBase(); 1394 Assert(StartupPID != 0); 1395 StartupStatus = STARTUP_RUNNING; 1396 pmState = PM_STARTUP; 1397 1398 /* Some workers may be scheduled to start now */ 1399 maybe_start_bgworkers(); 1400 1401 status = ServerLoop(); 1402 1403 /* 1404 * ServerLoop probably shouldn't ever return, but if it does, close down. 1405 */ 1406 ExitPostmaster(status != STATUS_OK); 1407 1408 abort(); /* not reached */ 1409 } 1410 1411 1412 /* 1413 * on_proc_exit callback to close server's listen sockets 1414 */ 1415 static void 1416 CloseServerPorts(int status, Datum arg) 1417 { 1418 int i; 1419 1420 /* 1421 * First, explicitly close all the socket FDs. We used to just let this 1422 * happen implicitly at postmaster exit, but it's better to close them 1423 * before we remove the postmaster.pid lockfile; otherwise there's a race 1424 * condition if a new postmaster wants to re-use the TCP port number. 1425 */ 1426 for (i = 0; i < MAXLISTEN; i++) 1427 { 1428 if (ListenSocket[i] != PGINVALID_SOCKET) 1429 { 1430 StreamClose(ListenSocket[i]); 1431 ListenSocket[i] = PGINVALID_SOCKET; 1432 } 1433 } 1434 1435 /* 1436 * Next, remove any filesystem entries for Unix sockets. To avoid race 1437 * conditions against incoming postmasters, this must happen after closing 1438 * the sockets and before removing lock files. 1439 */ 1440 RemoveSocketFiles(); 1441 1442 /* 1443 * We don't do anything about socket lock files here; those will be 1444 * removed in a later on_proc_exit callback. 1445 */ 1446 } 1447 1448 /* 1449 * on_proc_exit callback to delete external_pid_file 1450 */ 1451 static void 1452 unlink_external_pid_file(int status, Datum arg) 1453 { 1454 if (external_pid_file) 1455 unlink(external_pid_file); 1456 } 1457 1458 1459 /* 1460 * Compute and check the directory paths to files that are part of the 1461 * installation (as deduced from the postgres executable's own location) 1462 */ 1463 static void 1464 getInstallationPaths(const char *argv0) 1465 { 1466 DIR *pdir; 1467 1468 /* Locate the postgres executable itself */ 1469 if (find_my_exec(argv0, my_exec_path) < 0) 1470 elog(FATAL, "%s: could not locate my own executable path", argv0); 1471 1472 #ifdef EXEC_BACKEND 1473 /* Locate executable backend before we change working directory */ 1474 if (find_other_exec(argv0, "postgres", PG_BACKEND_VERSIONSTR, 1475 postgres_exec_path) < 0) 1476 ereport(FATAL, 1477 (errmsg("%s: could not locate matching postgres executable", 1478 argv0))); 1479 #endif 1480 1481 /* 1482 * Locate the pkglib directory --- this has to be set early in case we try 1483 * to load any modules from it in response to postgresql.conf entries. 1484 */ 1485 get_pkglib_path(my_exec_path, pkglib_path); 1486 1487 /* 1488 * Verify that there's a readable directory there; otherwise the Postgres 1489 * installation is incomplete or corrupt. (A typical cause of this 1490 * failure is that the postgres executable has been moved or hardlinked to 1491 * some directory that's not a sibling of the installation lib/ 1492 * directory.) 1493 */ 1494 pdir = AllocateDir(pkglib_path); 1495 if (pdir == NULL) 1496 ereport(ERROR, 1497 (errcode_for_file_access(), 1498 errmsg("could not open directory \"%s\": %m", 1499 pkglib_path), 1500 errhint("This may indicate an incomplete PostgreSQL installation, or that the file \"%s\" has been moved away from its proper location.", 1501 my_exec_path))); 1502 FreeDir(pdir); 1503 1504 /* 1505 * XXX is it worth similarly checking the share/ directory? If the lib/ 1506 * directory is there, then share/ probably is too. 1507 */ 1508 } 1509 1510 /* 1511 * Check that pg_control exists in the correct location in the data directory. 1512 * 1513 * No attempt is made to validate the contents of pg_control here. This is 1514 * just a sanity check to see if we are looking at a real data directory. 1515 */ 1516 static void 1517 checkControlFile(void) 1518 { 1519 char path[MAXPGPATH]; 1520 FILE *fp; 1521 1522 snprintf(path, sizeof(path), "%s/global/pg_control", DataDir); 1523 1524 fp = AllocateFile(path, PG_BINARY_R); 1525 if (fp == NULL) 1526 { 1527 write_stderr("%s: could not find the database system\n" 1528 "Expected to find it in the directory \"%s\",\n" 1529 "but could not open file \"%s\": %s\n", 1530 progname, DataDir, path, strerror(errno)); 1531 ExitPostmaster(2); 1532 } 1533 FreeFile(fp); 1534 } 1535 1536 /* 1537 * Determine how long should we let ServerLoop sleep. 1538 * 1539 * In normal conditions we wait at most one minute, to ensure that the other 1540 * background tasks handled by ServerLoop get done even when no requests are 1541 * arriving. However, if there are background workers waiting to be started, 1542 * we don't actually sleep so that they are quickly serviced. Other exception 1543 * cases are as shown in the code. 1544 */ 1545 static void 1546 DetermineSleepTime(struct timeval *timeout) 1547 { 1548 TimestampTz next_wakeup = 0; 1549 1550 /* 1551 * Normal case: either there are no background workers at all, or we're in 1552 * a shutdown sequence (during which we ignore bgworkers altogether). 1553 */ 1554 if (Shutdown > NoShutdown || 1555 (!StartWorkerNeeded && !HaveCrashedWorker)) 1556 { 1557 if (AbortStartTime != 0) 1558 { 1559 /* time left to abort; clamp to 0 in case it already expired */ 1560 timeout->tv_sec = SIGKILL_CHILDREN_AFTER_SECS - 1561 (time(NULL) - AbortStartTime); 1562 timeout->tv_sec = Max(timeout->tv_sec, 0); 1563 timeout->tv_usec = 0; 1564 } 1565 else 1566 { 1567 timeout->tv_sec = 60; 1568 timeout->tv_usec = 0; 1569 } 1570 return; 1571 } 1572 1573 if (StartWorkerNeeded) 1574 { 1575 timeout->tv_sec = 0; 1576 timeout->tv_usec = 0; 1577 return; 1578 } 1579 1580 if (HaveCrashedWorker) 1581 { 1582 slist_mutable_iter siter; 1583 1584 /* 1585 * When there are crashed bgworkers, we sleep just long enough that 1586 * they are restarted when they request to be. Scan the list to 1587 * determine the minimum of all wakeup times according to most recent 1588 * crash time and requested restart interval. 1589 */ 1590 slist_foreach_modify(siter, &BackgroundWorkerList) 1591 { 1592 RegisteredBgWorker *rw; 1593 TimestampTz this_wakeup; 1594 1595 rw = slist_container(RegisteredBgWorker, rw_lnode, siter.cur); 1596 1597 if (rw->rw_crashed_at == 0) 1598 continue; 1599 1600 if (rw->rw_worker.bgw_restart_time == BGW_NEVER_RESTART 1601 || rw->rw_terminate) 1602 { 1603 ForgetBackgroundWorker(&siter); 1604 continue; 1605 } 1606 1607 this_wakeup = TimestampTzPlusMilliseconds(rw->rw_crashed_at, 1608 1000L * rw->rw_worker.bgw_restart_time); 1609 if (next_wakeup == 0 || this_wakeup < next_wakeup) 1610 next_wakeup = this_wakeup; 1611 } 1612 } 1613 1614 if (next_wakeup != 0) 1615 { 1616 long secs; 1617 int microsecs; 1618 1619 TimestampDifference(GetCurrentTimestamp(), next_wakeup, 1620 &secs, µsecs); 1621 timeout->tv_sec = secs; 1622 timeout->tv_usec = microsecs; 1623 1624 /* Ensure we don't exceed one minute */ 1625 if (timeout->tv_sec > 60) 1626 { 1627 timeout->tv_sec = 60; 1628 timeout->tv_usec = 0; 1629 } 1630 } 1631 else 1632 { 1633 timeout->tv_sec = 60; 1634 timeout->tv_usec = 0; 1635 } 1636 } 1637 1638 /* 1639 * Main idle loop of postmaster 1640 * 1641 * NB: Needs to be called with signals blocked 1642 */ 1643 static int 1644 ServerLoop(void) 1645 { 1646 fd_set readmask; 1647 int nSockets; 1648 time_t last_lockfile_recheck_time, 1649 last_touch_time; 1650 1651 last_lockfile_recheck_time = last_touch_time = time(NULL); 1652 1653 nSockets = initMasks(&readmask); 1654 1655 for (;;) 1656 { 1657 fd_set rmask; 1658 int selres; 1659 time_t now; 1660 1661 /* 1662 * Wait for a connection request to arrive. 1663 * 1664 * We block all signals except while sleeping. That makes it safe for 1665 * signal handlers, which again block all signals while executing, to 1666 * do nontrivial work. 1667 * 1668 * If we are in PM_WAIT_DEAD_END state, then we don't want to accept 1669 * any new connections, so we don't call select(), and just sleep. 1670 */ 1671 memcpy((char *) &rmask, (char *) &readmask, sizeof(fd_set)); 1672 1673 if (pmState == PM_WAIT_DEAD_END) 1674 { 1675 PG_SETMASK(&UnBlockSig); 1676 1677 pg_usleep(100000L); /* 100 msec seems reasonable */ 1678 selres = 0; 1679 1680 PG_SETMASK(&BlockSig); 1681 } 1682 else 1683 { 1684 /* must set timeout each time; some OSes change it! */ 1685 struct timeval timeout; 1686 1687 /* Needs to run with blocked signals! */ 1688 DetermineSleepTime(&timeout); 1689 1690 PG_SETMASK(&UnBlockSig); 1691 1692 selres = select(nSockets, &rmask, NULL, NULL, &timeout); 1693 1694 PG_SETMASK(&BlockSig); 1695 } 1696 1697 /* Now check the select() result */ 1698 if (selres < 0) 1699 { 1700 if (errno != EINTR && errno != EWOULDBLOCK) 1701 { 1702 ereport(LOG, 1703 (errcode_for_socket_access(), 1704 errmsg("select() failed in postmaster: %m"))); 1705 return STATUS_ERROR; 1706 } 1707 } 1708 1709 /* 1710 * New connection pending on any of our sockets? If so, fork a child 1711 * process to deal with it. 1712 */ 1713 if (selres > 0) 1714 { 1715 int i; 1716 1717 for (i = 0; i < MAXLISTEN; i++) 1718 { 1719 if (ListenSocket[i] == PGINVALID_SOCKET) 1720 break; 1721 if (FD_ISSET(ListenSocket[i], &rmask)) 1722 { 1723 Port *port; 1724 1725 port = ConnCreate(ListenSocket[i]); 1726 if (port) 1727 { 1728 BackendStartup(port); 1729 1730 /* 1731 * We no longer need the open socket or port structure 1732 * in this process 1733 */ 1734 StreamClose(port->sock); 1735 ConnFree(port); 1736 } 1737 } 1738 } 1739 } 1740 1741 /* If we have lost the log collector, try to start a new one */ 1742 if (SysLoggerPID == 0 && Logging_collector) 1743 SysLoggerPID = SysLogger_Start(); 1744 1745 /* 1746 * If no background writer process is running, and we are not in a 1747 * state that prevents it, start one. It doesn't matter if this 1748 * fails, we'll just try again later. Likewise for the checkpointer. 1749 */ 1750 if (pmState == PM_RUN || pmState == PM_RECOVERY || 1751 pmState == PM_HOT_STANDBY) 1752 { 1753 if (CheckpointerPID == 0) 1754 CheckpointerPID = StartCheckpointer(); 1755 if (BgWriterPID == 0) 1756 BgWriterPID = StartBackgroundWriter(); 1757 } 1758 1759 /* 1760 * Likewise, if we have lost the walwriter process, try to start a new 1761 * one. But this is needed only in normal operation (else we cannot 1762 * be writing any new WAL). 1763 */ 1764 if (WalWriterPID == 0 && pmState == PM_RUN) 1765 WalWriterPID = StartWalWriter(); 1766 1767 /* 1768 * If we have lost the autovacuum launcher, try to start a new one. We 1769 * don't want autovacuum to run in binary upgrade mode because 1770 * autovacuum might update relfrozenxid for empty tables before the 1771 * physical files are put in place. 1772 */ 1773 if (!IsBinaryUpgrade && AutoVacPID == 0 && 1774 (AutoVacuumingActive() || start_autovac_launcher) && 1775 pmState == PM_RUN) 1776 { 1777 AutoVacPID = StartAutoVacLauncher(); 1778 if (AutoVacPID != 0) 1779 start_autovac_launcher = false; /* signal processed */ 1780 } 1781 1782 /* If we have lost the stats collector, try to start a new one */ 1783 if (PgStatPID == 0 && 1784 (pmState == PM_RUN || pmState == PM_HOT_STANDBY)) 1785 PgStatPID = pgstat_start(); 1786 1787 /* If we have lost the archiver, try to start a new one. */ 1788 if (PgArchPID == 0 && PgArchStartupAllowed()) 1789 PgArchPID = pgarch_start(); 1790 1791 /* If we need to signal the autovacuum launcher, do so now */ 1792 if (avlauncher_needs_signal) 1793 { 1794 avlauncher_needs_signal = false; 1795 if (AutoVacPID != 0) 1796 kill(AutoVacPID, SIGUSR2); 1797 } 1798 1799 /* If we need to start a WAL receiver, try to do that now */ 1800 if (WalReceiverRequested) 1801 MaybeStartWalReceiver(); 1802 1803 /* Get other worker processes running, if needed */ 1804 if (StartWorkerNeeded || HaveCrashedWorker) 1805 maybe_start_bgworkers(); 1806 1807 #ifdef HAVE_PTHREAD_IS_THREADED_NP 1808 1809 /* 1810 * With assertions enabled, check regularly for appearance of 1811 * additional threads. All builds check at start and exit. 1812 */ 1813 Assert(pthread_is_threaded_np() == 0); 1814 #endif 1815 1816 /* 1817 * Lastly, check to see if it's time to do some things that we don't 1818 * want to do every single time through the loop, because they're a 1819 * bit expensive. Note that there's up to a minute of slop in when 1820 * these tasks will be performed, since DetermineSleepTime() will let 1821 * us sleep at most that long; except for SIGKILL timeout which has 1822 * special-case logic there. 1823 */ 1824 now = time(NULL); 1825 1826 /* 1827 * If we already sent SIGQUIT to children and they are slow to shut 1828 * down, it's time to send them SIGKILL. This doesn't happen 1829 * normally, but under certain conditions backends can get stuck while 1830 * shutting down. This is a last measure to get them unwedged. 1831 * 1832 * Note we also do this during recovery from a process crash. 1833 */ 1834 if ((Shutdown >= ImmediateShutdown || (FatalError && !SendStop)) && 1835 AbortStartTime != 0 && 1836 (now - AbortStartTime) >= SIGKILL_CHILDREN_AFTER_SECS) 1837 { 1838 /* We were gentle with them before. Not anymore */ 1839 TerminateChildren(SIGKILL); 1840 /* reset flag so we don't SIGKILL again */ 1841 AbortStartTime = 0; 1842 } 1843 1844 /* 1845 * Once a minute, verify that postmaster.pid hasn't been removed or 1846 * overwritten. If it has, we force a shutdown. This avoids having 1847 * postmasters and child processes hanging around after their database 1848 * is gone, and maybe causing problems if a new database cluster is 1849 * created in the same place. It also provides some protection 1850 * against a DBA foolishly removing postmaster.pid and manually 1851 * starting a new postmaster. Data corruption is likely to ensue from 1852 * that anyway, but we can minimize the damage by aborting ASAP. 1853 */ 1854 if (now - last_lockfile_recheck_time >= 1 * SECS_PER_MINUTE) 1855 { 1856 if (!RecheckDataDirLockFile()) 1857 { 1858 ereport(LOG, 1859 (errmsg("performing immediate shutdown because data directory lock file is invalid"))); 1860 kill(MyProcPid, SIGQUIT); 1861 } 1862 last_lockfile_recheck_time = now; 1863 } 1864 1865 /* 1866 * Touch Unix socket and lock files every 58 minutes, to ensure that 1867 * they are not removed by overzealous /tmp-cleaning tasks. We assume 1868 * no one runs cleaners with cutoff times of less than an hour ... 1869 */ 1870 if (now - last_touch_time >= 58 * SECS_PER_MINUTE) 1871 { 1872 TouchSocketFiles(); 1873 TouchSocketLockFiles(); 1874 last_touch_time = now; 1875 } 1876 } 1877 } 1878 1879 /* 1880 * Initialise the masks for select() for the ports we are listening on. 1881 * Return the number of sockets to listen on. 1882 */ 1883 static int 1884 initMasks(fd_set *rmask) 1885 { 1886 int maxsock = -1; 1887 int i; 1888 1889 FD_ZERO(rmask); 1890 1891 for (i = 0; i < MAXLISTEN; i++) 1892 { 1893 int fd = ListenSocket[i]; 1894 1895 if (fd == PGINVALID_SOCKET) 1896 break; 1897 FD_SET(fd, rmask); 1898 1899 if (fd > maxsock) 1900 maxsock = fd; 1901 } 1902 1903 return maxsock + 1; 1904 } 1905 1906 1907 /* 1908 * Read a client's startup packet and do something according to it. 1909 * 1910 * Returns STATUS_OK or STATUS_ERROR, or might call ereport(FATAL) and 1911 * not return at all. 1912 * 1913 * (Note that ereport(FATAL) stuff is sent to the client, so only use it 1914 * if that's what you want. Return STATUS_ERROR if you don't want to 1915 * send anything to the client, which would typically be appropriate 1916 * if we detect a communications failure.) 1917 */ 1918 static int 1919 ProcessStartupPacket(Port *port, bool SSLdone) 1920 { 1921 int32 len; 1922 void *buf; 1923 ProtocolVersion proto; 1924 MemoryContext oldcontext; 1925 1926 pq_startmsgread(); 1927 if (pq_getbytes((char *) &len, 4) == EOF) 1928 { 1929 /* 1930 * EOF after SSLdone probably means the client didn't like our 1931 * response to NEGOTIATE_SSL_CODE. That's not an error condition, so 1932 * don't clutter the log with a complaint. 1933 */ 1934 if (!SSLdone) 1935 ereport(COMMERROR, 1936 (errcode(ERRCODE_PROTOCOL_VIOLATION), 1937 errmsg("incomplete startup packet"))); 1938 return STATUS_ERROR; 1939 } 1940 1941 len = pg_ntoh32(len); 1942 len -= 4; 1943 1944 if (len < (int32) sizeof(ProtocolVersion) || 1945 len > MAX_STARTUP_PACKET_LENGTH) 1946 { 1947 ereport(COMMERROR, 1948 (errcode(ERRCODE_PROTOCOL_VIOLATION), 1949 errmsg("invalid length of startup packet"))); 1950 return STATUS_ERROR; 1951 } 1952 1953 /* 1954 * Allocate at least the size of an old-style startup packet, plus one 1955 * extra byte, and make sure all are zeroes. This ensures we will have 1956 * null termination of all strings, in both fixed- and variable-length 1957 * packet layouts. 1958 */ 1959 if (len <= (int32) sizeof(StartupPacket)) 1960 buf = palloc0(sizeof(StartupPacket) + 1); 1961 else 1962 buf = palloc0(len + 1); 1963 1964 if (pq_getbytes(buf, len) == EOF) 1965 { 1966 ereport(COMMERROR, 1967 (errcode(ERRCODE_PROTOCOL_VIOLATION), 1968 errmsg("incomplete startup packet"))); 1969 return STATUS_ERROR; 1970 } 1971 pq_endmsgread(); 1972 1973 /* 1974 * The first field is either a protocol version number or a special 1975 * request code. 1976 */ 1977 port->proto = proto = pg_ntoh32(*((ProtocolVersion *) buf)); 1978 1979 if (proto == CANCEL_REQUEST_CODE) 1980 { 1981 processCancelRequest(port, buf); 1982 /* Not really an error, but we don't want to proceed further */ 1983 return STATUS_ERROR; 1984 } 1985 1986 if (proto == NEGOTIATE_SSL_CODE && !SSLdone) 1987 { 1988 char SSLok; 1989 1990 #ifdef USE_SSL 1991 /* No SSL when disabled or on Unix sockets */ 1992 if (!LoadedSSL || IS_AF_UNIX(port->laddr.addr.ss_family)) 1993 SSLok = 'N'; 1994 else 1995 SSLok = 'S'; /* Support for SSL */ 1996 #else 1997 SSLok = 'N'; /* No support for SSL */ 1998 #endif 1999 2000 retry1: 2001 if (send(port->sock, &SSLok, 1, 0) != 1) 2002 { 2003 if (errno == EINTR) 2004 goto retry1; /* if interrupted, just retry */ 2005 ereport(COMMERROR, 2006 (errcode_for_socket_access(), 2007 errmsg("failed to send SSL negotiation response: %m"))); 2008 return STATUS_ERROR; /* close the connection */ 2009 } 2010 2011 #ifdef USE_SSL 2012 if (SSLok == 'S' && secure_open_server(port) == -1) 2013 return STATUS_ERROR; 2014 #endif 2015 2016 /* 2017 * At this point we should have no data already buffered. If we do, 2018 * it was received before we performed the SSL handshake, so it wasn't 2019 * encrypted and indeed may have been injected by a man-in-the-middle. 2020 * We report this case to the client. 2021 */ 2022 if (pq_buffer_has_data()) 2023 ereport(FATAL, 2024 (errcode(ERRCODE_PROTOCOL_VIOLATION), 2025 errmsg("received unencrypted data after SSL request"), 2026 errdetail("This could be either a client-software bug or evidence of an attempted man-in-the-middle attack."))); 2027 2028 /* regular startup packet, cancel, etc packet should follow... */ 2029 /* but not another SSL negotiation request */ 2030 return ProcessStartupPacket(port, true); 2031 } 2032 2033 /* Could add additional special packet types here */ 2034 2035 /* 2036 * Set FrontendProtocol now so that ereport() knows what format to send if 2037 * we fail during startup. 2038 */ 2039 FrontendProtocol = proto; 2040 2041 /* Check that the major protocol version is in range. */ 2042 if (PG_PROTOCOL_MAJOR(proto) < PG_PROTOCOL_MAJOR(PG_PROTOCOL_EARLIEST) || 2043 PG_PROTOCOL_MAJOR(proto) > PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST)) 2044 ereport(FATAL, 2045 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), 2046 errmsg("unsupported frontend protocol %u.%u: server supports %u.0 to %u.%u", 2047 PG_PROTOCOL_MAJOR(proto), PG_PROTOCOL_MINOR(proto), 2048 PG_PROTOCOL_MAJOR(PG_PROTOCOL_EARLIEST), 2049 PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST), 2050 PG_PROTOCOL_MINOR(PG_PROTOCOL_LATEST)))); 2051 2052 /* 2053 * Now fetch parameters out of startup packet and save them into the Port 2054 * structure. All data structures attached to the Port struct must be 2055 * allocated in TopMemoryContext so that they will remain available in a 2056 * running backend (even after PostmasterContext is destroyed). We need 2057 * not worry about leaking this storage on failure, since we aren't in the 2058 * postmaster process anymore. 2059 */ 2060 oldcontext = MemoryContextSwitchTo(TopMemoryContext); 2061 2062 if (PG_PROTOCOL_MAJOR(proto) >= 3) 2063 { 2064 int32 offset = sizeof(ProtocolVersion); 2065 List *unrecognized_protocol_options = NIL; 2066 2067 /* 2068 * Scan packet body for name/option pairs. We can assume any string 2069 * beginning within the packet body is null-terminated, thanks to 2070 * zeroing extra byte above. 2071 */ 2072 port->guc_options = NIL; 2073 2074 while (offset < len) 2075 { 2076 char *nameptr = ((char *) buf) + offset; 2077 int32 valoffset; 2078 char *valptr; 2079 2080 if (*nameptr == '\0') 2081 break; /* found packet terminator */ 2082 valoffset = offset + strlen(nameptr) + 1; 2083 if (valoffset >= len) 2084 break; /* missing value, will complain below */ 2085 valptr = ((char *) buf) + valoffset; 2086 2087 if (strcmp(nameptr, "database") == 0) 2088 port->database_name = pstrdup(valptr); 2089 else if (strcmp(nameptr, "user") == 0) 2090 port->user_name = pstrdup(valptr); 2091 else if (strcmp(nameptr, "options") == 0) 2092 port->cmdline_options = pstrdup(valptr); 2093 else if (strcmp(nameptr, "replication") == 0) 2094 { 2095 /* 2096 * Due to backward compatibility concerns the replication 2097 * parameter is a hybrid beast which allows the value to be 2098 * either boolean or the string 'database'. The latter 2099 * connects to a specific database which is e.g. required for 2100 * logical decoding while. 2101 */ 2102 if (strcmp(valptr, "database") == 0) 2103 { 2104 am_walsender = true; 2105 am_db_walsender = true; 2106 } 2107 else if (!parse_bool(valptr, &am_walsender)) 2108 ereport(FATAL, 2109 (errcode(ERRCODE_INVALID_PARAMETER_VALUE), 2110 errmsg("invalid value for parameter \"%s\": \"%s\"", 2111 "replication", 2112 valptr), 2113 errhint("Valid values are: \"false\", 0, \"true\", 1, \"database\"."))); 2114 } 2115 else if (strncmp(nameptr, "_pq_.", 5) == 0) 2116 { 2117 /* 2118 * Any option beginning with _pq_. is reserved for use as a 2119 * protocol-level option, but at present no such options are 2120 * defined. 2121 */ 2122 unrecognized_protocol_options = 2123 lappend(unrecognized_protocol_options, pstrdup(nameptr)); 2124 } 2125 else 2126 { 2127 /* Assume it's a generic GUC option */ 2128 port->guc_options = lappend(port->guc_options, 2129 pstrdup(nameptr)); 2130 port->guc_options = lappend(port->guc_options, 2131 pstrdup(valptr)); 2132 } 2133 offset = valoffset + strlen(valptr) + 1; 2134 } 2135 2136 /* 2137 * If we didn't find a packet terminator exactly at the end of the 2138 * given packet length, complain. 2139 */ 2140 if (offset != len - 1) 2141 ereport(FATAL, 2142 (errcode(ERRCODE_PROTOCOL_VIOLATION), 2143 errmsg("invalid startup packet layout: expected terminator as last byte"))); 2144 2145 /* 2146 * If the client requested a newer protocol version or if the client 2147 * requested any protocol options we didn't recognize, let them know 2148 * the newest minor protocol version we do support and the names of 2149 * any unrecognized options. 2150 */ 2151 if (PG_PROTOCOL_MINOR(proto) > PG_PROTOCOL_MINOR(PG_PROTOCOL_LATEST) || 2152 unrecognized_protocol_options != NIL) 2153 SendNegotiateProtocolVersion(unrecognized_protocol_options); 2154 } 2155 else 2156 { 2157 /* 2158 * Get the parameters from the old-style, fixed-width-fields startup 2159 * packet as C strings. The packet destination was cleared first so a 2160 * short packet has zeros silently added. We have to be prepared to 2161 * truncate the pstrdup result for oversize fields, though. 2162 */ 2163 StartupPacket *packet = (StartupPacket *) buf; 2164 2165 port->database_name = pstrdup(packet->database); 2166 if (strlen(port->database_name) > sizeof(packet->database)) 2167 port->database_name[sizeof(packet->database)] = '\0'; 2168 port->user_name = pstrdup(packet->user); 2169 if (strlen(port->user_name) > sizeof(packet->user)) 2170 port->user_name[sizeof(packet->user)] = '\0'; 2171 port->cmdline_options = pstrdup(packet->options); 2172 if (strlen(port->cmdline_options) > sizeof(packet->options)) 2173 port->cmdline_options[sizeof(packet->options)] = '\0'; 2174 port->guc_options = NIL; 2175 } 2176 2177 /* Check a user name was given. */ 2178 if (port->user_name == NULL || port->user_name[0] == '\0') 2179 ereport(FATAL, 2180 (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION), 2181 errmsg("no PostgreSQL user name specified in startup packet"))); 2182 2183 /* The database defaults to the user name. */ 2184 if (port->database_name == NULL || port->database_name[0] == '\0') 2185 port->database_name = pstrdup(port->user_name); 2186 2187 if (Db_user_namespace) 2188 { 2189 /* 2190 * If user@, it is a global user, remove '@'. We only want to do this 2191 * if there is an '@' at the end and no earlier in the user string or 2192 * they may fake as a local user of another database attaching to this 2193 * database. 2194 */ 2195 if (strchr(port->user_name, '@') == 2196 port->user_name + strlen(port->user_name) - 1) 2197 *strchr(port->user_name, '@') = '\0'; 2198 else 2199 { 2200 /* Append '@' and dbname */ 2201 port->user_name = psprintf("%s@%s", port->user_name, port->database_name); 2202 } 2203 } 2204 2205 /* 2206 * Truncate given database and user names to length of a Postgres name. 2207 * This avoids lookup failures when overlength names are given. 2208 */ 2209 if (strlen(port->database_name) >= NAMEDATALEN) 2210 port->database_name[NAMEDATALEN - 1] = '\0'; 2211 if (strlen(port->user_name) >= NAMEDATALEN) 2212 port->user_name[NAMEDATALEN - 1] = '\0'; 2213 2214 /* 2215 * Normal walsender backends, e.g. for streaming replication, are not 2216 * connected to a particular database. But walsenders used for logical 2217 * replication need to connect to a specific database. We allow streaming 2218 * replication commands to be issued even if connected to a database as it 2219 * can make sense to first make a basebackup and then stream changes 2220 * starting from that. 2221 */ 2222 if (am_walsender && !am_db_walsender) 2223 port->database_name[0] = '\0'; 2224 2225 /* 2226 * Done putting stuff in TopMemoryContext. 2227 */ 2228 MemoryContextSwitchTo(oldcontext); 2229 2230 /* 2231 * If we're going to reject the connection due to database state, say so 2232 * now instead of wasting cycles on an authentication exchange. (This also 2233 * allows a pg_ping utility to be written.) 2234 */ 2235 switch (port->canAcceptConnections) 2236 { 2237 case CAC_STARTUP: 2238 ereport(FATAL, 2239 (errcode(ERRCODE_CANNOT_CONNECT_NOW), 2240 errmsg("the database system is starting up"))); 2241 break; 2242 case CAC_SHUTDOWN: 2243 ereport(FATAL, 2244 (errcode(ERRCODE_CANNOT_CONNECT_NOW), 2245 errmsg("the database system is shutting down"))); 2246 break; 2247 case CAC_RECOVERY: 2248 ereport(FATAL, 2249 (errcode(ERRCODE_CANNOT_CONNECT_NOW), 2250 errmsg("the database system is in recovery mode"))); 2251 break; 2252 case CAC_TOOMANY: 2253 ereport(FATAL, 2254 (errcode(ERRCODE_TOO_MANY_CONNECTIONS), 2255 errmsg("sorry, too many clients already"))); 2256 break; 2257 case CAC_SUPERUSER: 2258 /* OK for now, will check in InitPostgres */ 2259 break; 2260 case CAC_OK: 2261 break; 2262 } 2263 2264 return STATUS_OK; 2265 } 2266 2267 /* 2268 * Send a NegotiateProtocolVersion to the client. This lets the client know 2269 * that they have requested a newer minor protocol version than we are able 2270 * to speak. We'll speak the highest version we know about; the client can, 2271 * of course, abandon the connection if that's a problem. 2272 * 2273 * We also include in the response a list of protocol options we didn't 2274 * understand. This allows clients to include optional parameters that might 2275 * be present either in newer protocol versions or third-party protocol 2276 * extensions without fear of having to reconnect if those options are not 2277 * understood, while at the same time making certain that the client is aware 2278 * of which options were actually accepted. 2279 */ 2280 static void 2281 SendNegotiateProtocolVersion(List *unrecognized_protocol_options) 2282 { 2283 StringInfoData buf; 2284 ListCell *lc; 2285 2286 pq_beginmessage(&buf, 'v'); /* NegotiateProtocolVersion */ 2287 pq_sendint32(&buf, PG_PROTOCOL_LATEST); 2288 pq_sendint32(&buf, list_length(unrecognized_protocol_options)); 2289 foreach(lc, unrecognized_protocol_options) 2290 pq_sendstring(&buf, lfirst(lc)); 2291 pq_endmessage(&buf); 2292 2293 /* no need to flush, some other message will follow */ 2294 } 2295 2296 /* 2297 * The client has sent a cancel request packet, not a normal 2298 * start-a-new-connection packet. Perform the necessary processing. 2299 * Nothing is sent back to the client. 2300 */ 2301 static void 2302 processCancelRequest(Port *port, void *pkt) 2303 { 2304 CancelRequestPacket *canc = (CancelRequestPacket *) pkt; 2305 int backendPID; 2306 int32 cancelAuthCode; 2307 Backend *bp; 2308 2309 #ifndef EXEC_BACKEND 2310 dlist_iter iter; 2311 #else 2312 int i; 2313 #endif 2314 2315 backendPID = (int) pg_ntoh32(canc->backendPID); 2316 cancelAuthCode = (int32) pg_ntoh32(canc->cancelAuthCode); 2317 2318 /* 2319 * See if we have a matching backend. In the EXEC_BACKEND case, we can no 2320 * longer access the postmaster's own backend list, and must rely on the 2321 * duplicate array in shared memory. 2322 */ 2323 #ifndef EXEC_BACKEND 2324 dlist_foreach(iter, &BackendList) 2325 { 2326 bp = dlist_container(Backend, elem, iter.cur); 2327 #else 2328 for (i = MaxLivePostmasterChildren() - 1; i >= 0; i--) 2329 { 2330 bp = (Backend *) &ShmemBackendArray[i]; 2331 #endif 2332 if (bp->pid == backendPID) 2333 { 2334 if (bp->cancel_key == cancelAuthCode) 2335 { 2336 /* Found a match; signal that backend to cancel current op */ 2337 ereport(DEBUG2, 2338 (errmsg_internal("processing cancel request: sending SIGINT to process %d", 2339 backendPID))); 2340 signal_child(bp->pid, SIGINT); 2341 } 2342 else 2343 /* Right PID, wrong key: no way, Jose */ 2344 ereport(LOG, 2345 (errmsg("wrong key in cancel request for process %d", 2346 backendPID))); 2347 return; 2348 } 2349 } 2350 2351 /* No matching backend */ 2352 ereport(LOG, 2353 (errmsg("PID %d in cancel request did not match any process", 2354 backendPID))); 2355 } 2356 2357 /* 2358 * canAcceptConnections --- check to see if database state allows connections 2359 * of the specified type. backend_type can be BACKEND_TYPE_NORMAL, 2360 * BACKEND_TYPE_AUTOVAC, or BACKEND_TYPE_BGWORKER. (Note that we don't yet 2361 * know whether a NORMAL connection might turn into a walsender.) 2362 */ 2363 static CAC_state 2364 canAcceptConnections(int backend_type) 2365 { 2366 CAC_state result = CAC_OK; 2367 2368 /* 2369 * Can't start backends when in startup/shutdown/inconsistent recovery 2370 * state. We treat autovac workers the same as user backends for this 2371 * purpose. However, bgworkers are excluded from this test; we expect 2372 * bgworker_should_start_now() decided whether the DB state allows them. 2373 */ 2374 if (pmState != PM_RUN && pmState != PM_HOT_STANDBY && 2375 backend_type != BACKEND_TYPE_BGWORKER) 2376 { 2377 if (Shutdown > NoShutdown) 2378 return CAC_SHUTDOWN; /* shutdown is pending */ 2379 else if (!FatalError && 2380 (pmState == PM_STARTUP || 2381 pmState == PM_RECOVERY)) 2382 return CAC_STARTUP; /* normal startup */ 2383 else 2384 return CAC_RECOVERY; /* else must be crash recovery */ 2385 } 2386 2387 /* 2388 * "Smart shutdown" restrictions are applied only to normal connections, 2389 * not to autovac workers or bgworkers. When only superusers can connect, 2390 * we return CAC_SUPERUSER to indicate that superuserness must be checked 2391 * later. Note that neither CAC_OK nor CAC_SUPERUSER can safely be 2392 * returned until we have checked for too many children. 2393 */ 2394 if (connsAllowed != ALLOW_ALL_CONNS && 2395 backend_type == BACKEND_TYPE_NORMAL) 2396 { 2397 if (connsAllowed == ALLOW_SUPERUSER_CONNS) 2398 result = CAC_SUPERUSER; /* allow superusers only */ 2399 else 2400 return CAC_SHUTDOWN; /* shutdown is pending */ 2401 } 2402 2403 /* 2404 * Don't start too many children. 2405 * 2406 * We allow more connections here than we can have backends because some 2407 * might still be authenticating; they might fail auth, or some existing 2408 * backend might exit before the auth cycle is completed. The exact 2409 * MaxBackends limit is enforced when a new backend tries to join the 2410 * shared-inval backend array. 2411 * 2412 * The limit here must match the sizes of the per-child-process arrays; 2413 * see comments for MaxLivePostmasterChildren(). 2414 */ 2415 if (CountChildren(BACKEND_TYPE_ALL) >= MaxLivePostmasterChildren()) 2416 result = CAC_TOOMANY; 2417 2418 return result; 2419 } 2420 2421 2422 /* 2423 * ConnCreate -- create a local connection data structure 2424 * 2425 * Returns NULL on failure, other than out-of-memory which is fatal. 2426 */ 2427 static Port * 2428 ConnCreate(int serverFd) 2429 { 2430 Port *port; 2431 2432 if (!(port = (Port *) calloc(1, sizeof(Port)))) 2433 { 2434 ereport(LOG, 2435 (errcode(ERRCODE_OUT_OF_MEMORY), 2436 errmsg("out of memory"))); 2437 ExitPostmaster(1); 2438 } 2439 2440 if (StreamConnection(serverFd, port) != STATUS_OK) 2441 { 2442 if (port->sock != PGINVALID_SOCKET) 2443 StreamClose(port->sock); 2444 ConnFree(port); 2445 return NULL; 2446 } 2447 2448 /* 2449 * Allocate GSSAPI specific state struct 2450 */ 2451 #ifndef EXEC_BACKEND 2452 #if defined(ENABLE_GSS) || defined(ENABLE_SSPI) 2453 port->gss = (pg_gssinfo *) calloc(1, sizeof(pg_gssinfo)); 2454 if (!port->gss) 2455 { 2456 ereport(LOG, 2457 (errcode(ERRCODE_OUT_OF_MEMORY), 2458 errmsg("out of memory"))); 2459 ExitPostmaster(1); 2460 } 2461 #endif 2462 #endif 2463 2464 return port; 2465 } 2466 2467 2468 /* 2469 * ConnFree -- free a local connection data structure 2470 */ 2471 static void 2472 ConnFree(Port *conn) 2473 { 2474 #ifdef USE_SSL 2475 secure_close(conn); 2476 #endif 2477 if (conn->gss) 2478 free(conn->gss); 2479 free(conn); 2480 } 2481 2482 2483 /* 2484 * ClosePostmasterPorts -- close all the postmaster's open sockets 2485 * 2486 * This is called during child process startup to release file descriptors 2487 * that are not needed by that child process. The postmaster still has 2488 * them open, of course. 2489 * 2490 * Note: we pass am_syslogger as a boolean because we don't want to set 2491 * the global variable yet when this is called. 2492 */ 2493 void 2494 ClosePostmasterPorts(bool am_syslogger) 2495 { 2496 int i; 2497 2498 #ifndef WIN32 2499 2500 /* 2501 * Close the write end of postmaster death watch pipe. It's important to 2502 * do this as early as possible, so that if postmaster dies, others won't 2503 * think that it's still running because we're holding the pipe open. 2504 */ 2505 if (close(postmaster_alive_fds[POSTMASTER_FD_OWN])) 2506 ereport(FATAL, 2507 (errcode_for_file_access(), 2508 errmsg_internal("could not close postmaster death monitoring pipe in child process: %m"))); 2509 postmaster_alive_fds[POSTMASTER_FD_OWN] = -1; 2510 #endif 2511 2512 /* Close the listen sockets */ 2513 for (i = 0; i < MAXLISTEN; i++) 2514 { 2515 if (ListenSocket[i] != PGINVALID_SOCKET) 2516 { 2517 StreamClose(ListenSocket[i]); 2518 ListenSocket[i] = PGINVALID_SOCKET; 2519 } 2520 } 2521 2522 /* If using syslogger, close the read side of the pipe */ 2523 if (!am_syslogger) 2524 { 2525 #ifndef WIN32 2526 if (syslogPipe[0] >= 0) 2527 close(syslogPipe[0]); 2528 syslogPipe[0] = -1; 2529 #else 2530 if (syslogPipe[0]) 2531 CloseHandle(syslogPipe[0]); 2532 syslogPipe[0] = 0; 2533 #endif 2534 } 2535 2536 #ifdef USE_BONJOUR 2537 /* If using Bonjour, close the connection to the mDNS daemon */ 2538 if (bonjour_sdref) 2539 close(DNSServiceRefSockFD(bonjour_sdref)); 2540 #endif 2541 } 2542 2543 2544 /* 2545 * reset_shared -- reset shared memory and semaphores 2546 */ 2547 static void 2548 reset_shared(int port) 2549 { 2550 /* 2551 * Create or re-create shared memory and semaphores. 2552 * 2553 * Note: in each "cycle of life" we will normally assign the same IPC keys 2554 * (if using SysV shmem and/or semas), since the port number is used to 2555 * determine IPC keys. This helps ensure that we will clean up dead IPC 2556 * objects if the postmaster crashes and is restarted. 2557 */ 2558 CreateSharedMemoryAndSemaphores(port); 2559 } 2560 2561 2562 /* 2563 * SIGHUP -- reread config files, and tell children to do same 2564 */ 2565 static void 2566 SIGHUP_handler(SIGNAL_ARGS) 2567 { 2568 int save_errno = errno; 2569 2570 /* 2571 * We rely on the signal mechanism to have blocked all signals ... except 2572 * on Windows, which lacks sigaction(), so we have to do it manually. 2573 */ 2574 #ifdef WIN32 2575 PG_SETMASK(&BlockSig); 2576 #endif 2577 2578 if (Shutdown <= SmartShutdown) 2579 { 2580 ereport(LOG, 2581 (errmsg("received SIGHUP, reloading configuration files"))); 2582 ProcessConfigFile(PGC_SIGHUP); 2583 SignalChildren(SIGHUP); 2584 if (StartupPID != 0) 2585 signal_child(StartupPID, SIGHUP); 2586 if (BgWriterPID != 0) 2587 signal_child(BgWriterPID, SIGHUP); 2588 if (CheckpointerPID != 0) 2589 signal_child(CheckpointerPID, SIGHUP); 2590 if (WalWriterPID != 0) 2591 signal_child(WalWriterPID, SIGHUP); 2592 if (WalReceiverPID != 0) 2593 signal_child(WalReceiverPID, SIGHUP); 2594 if (AutoVacPID != 0) 2595 signal_child(AutoVacPID, SIGHUP); 2596 if (PgArchPID != 0) 2597 signal_child(PgArchPID, SIGHUP); 2598 if (SysLoggerPID != 0) 2599 signal_child(SysLoggerPID, SIGHUP); 2600 if (PgStatPID != 0) 2601 signal_child(PgStatPID, SIGHUP); 2602 2603 /* Reload authentication config files too */ 2604 if (!load_hba()) 2605 ereport(LOG, 2606 (errmsg("pg_hba.conf was not reloaded"))); 2607 2608 if (!load_ident()) 2609 ereport(LOG, 2610 (errmsg("pg_ident.conf was not reloaded"))); 2611 2612 #ifdef USE_SSL 2613 /* Reload SSL configuration as well */ 2614 if (EnableSSL) 2615 { 2616 if (secure_initialize(false) == 0) 2617 LoadedSSL = true; 2618 else 2619 ereport(LOG, 2620 (errmsg("SSL configuration was not reloaded"))); 2621 } 2622 else 2623 { 2624 secure_destroy(); 2625 LoadedSSL = false; 2626 } 2627 #endif 2628 2629 #ifdef EXEC_BACKEND 2630 /* Update the starting-point file for future children */ 2631 write_nondefault_variables(PGC_SIGHUP); 2632 #endif 2633 } 2634 2635 #ifdef WIN32 2636 PG_SETMASK(&UnBlockSig); 2637 #endif 2638 2639 errno = save_errno; 2640 } 2641 2642 2643 /* 2644 * pmdie -- signal handler for processing various postmaster signals. 2645 */ 2646 static void 2647 pmdie(SIGNAL_ARGS) 2648 { 2649 int save_errno = errno; 2650 2651 /* 2652 * We rely on the signal mechanism to have blocked all signals ... except 2653 * on Windows, which lacks sigaction(), so we have to do it manually. 2654 */ 2655 #ifdef WIN32 2656 PG_SETMASK(&BlockSig); 2657 #endif 2658 2659 ereport(DEBUG2, 2660 (errmsg_internal("postmaster received signal %d", 2661 postgres_signal_arg))); 2662 2663 switch (postgres_signal_arg) 2664 { 2665 case SIGTERM: 2666 2667 /* 2668 * Smart Shutdown: 2669 * 2670 * Wait for children to end their work, then shut down. 2671 */ 2672 if (Shutdown >= SmartShutdown) 2673 break; 2674 Shutdown = SmartShutdown; 2675 ereport(LOG, 2676 (errmsg("received smart shutdown request"))); 2677 2678 /* Report status */ 2679 AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STOPPING); 2680 #ifdef USE_SYSTEMD 2681 sd_notify(0, "STOPPING=1"); 2682 #endif 2683 2684 /* 2685 * If we reached normal running, we have to wait for any online 2686 * backup mode to end; otherwise go straight to waiting for client 2687 * backends to exit. (The difference is that in the former state, 2688 * we'll still let in new superuser clients, so that somebody can 2689 * end the online backup mode.) If already in PM_STOP_BACKENDS or 2690 * a later state, do not change it. 2691 */ 2692 if (pmState == PM_RUN) 2693 connsAllowed = ALLOW_SUPERUSER_CONNS; 2694 else if (pmState == PM_HOT_STANDBY) 2695 connsAllowed = ALLOW_NO_CONNS; 2696 else if (pmState == PM_STARTUP || pmState == PM_RECOVERY) 2697 { 2698 /* There should be no clients, so proceed to stop children */ 2699 pmState = PM_STOP_BACKENDS; 2700 } 2701 2702 /* 2703 * Now wait for online backup mode to end and backends to exit. If 2704 * that is already the case, PostmasterStateMachine will take the 2705 * next step. 2706 */ 2707 PostmasterStateMachine(); 2708 break; 2709 2710 case SIGINT: 2711 2712 /* 2713 * Fast Shutdown: 2714 * 2715 * Abort all children with SIGTERM (rollback active transactions 2716 * and exit) and shut down when they are gone. 2717 */ 2718 if (Shutdown >= FastShutdown) 2719 break; 2720 Shutdown = FastShutdown; 2721 ereport(LOG, 2722 (errmsg("received fast shutdown request"))); 2723 2724 /* Report status */ 2725 AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STOPPING); 2726 #ifdef USE_SYSTEMD 2727 sd_notify(0, "STOPPING=1"); 2728 #endif 2729 2730 if (pmState == PM_STARTUP || pmState == PM_RECOVERY) 2731 { 2732 /* Just shut down background processes silently */ 2733 pmState = PM_STOP_BACKENDS; 2734 } 2735 else if (pmState == PM_RUN || 2736 pmState == PM_HOT_STANDBY) 2737 { 2738 /* Report that we're about to zap live client sessions */ 2739 ereport(LOG, 2740 (errmsg("aborting any active transactions"))); 2741 pmState = PM_STOP_BACKENDS; 2742 } 2743 2744 /* 2745 * PostmasterStateMachine will issue any necessary signals, or 2746 * take the next step if no child processes need to be killed. 2747 */ 2748 PostmasterStateMachine(); 2749 break; 2750 2751 case SIGQUIT: 2752 2753 /* 2754 * Immediate Shutdown: 2755 * 2756 * abort all children with SIGQUIT, wait for them to exit, 2757 * terminate remaining ones with SIGKILL, then exit without 2758 * attempt to properly shut down the data base system. 2759 */ 2760 if (Shutdown >= ImmediateShutdown) 2761 break; 2762 Shutdown = ImmediateShutdown; 2763 ereport(LOG, 2764 (errmsg("received immediate shutdown request"))); 2765 2766 /* Report status */ 2767 AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STOPPING); 2768 #ifdef USE_SYSTEMD 2769 sd_notify(0, "STOPPING=1"); 2770 #endif 2771 2772 TerminateChildren(SIGQUIT); 2773 pmState = PM_WAIT_BACKENDS; 2774 2775 /* set stopwatch for them to die */ 2776 AbortStartTime = time(NULL); 2777 2778 /* 2779 * Now wait for backends to exit. If there are none, 2780 * PostmasterStateMachine will take the next step. 2781 */ 2782 PostmasterStateMachine(); 2783 break; 2784 } 2785 2786 #ifdef WIN32 2787 PG_SETMASK(&UnBlockSig); 2788 #endif 2789 2790 errno = save_errno; 2791 } 2792 2793 /* 2794 * Reaper -- signal handler to cleanup after a child process dies. 2795 */ 2796 static void 2797 reaper(SIGNAL_ARGS) 2798 { 2799 int save_errno = errno; 2800 int pid; /* process id of dead child process */ 2801 int exitstatus; /* its exit status */ 2802 2803 /* 2804 * We rely on the signal mechanism to have blocked all signals ... except 2805 * on Windows, which lacks sigaction(), so we have to do it manually. 2806 */ 2807 #ifdef WIN32 2808 PG_SETMASK(&BlockSig); 2809 #endif 2810 2811 ereport(DEBUG4, 2812 (errmsg_internal("reaping dead processes"))); 2813 2814 while ((pid = waitpid(-1, &exitstatus, WNOHANG)) > 0) 2815 { 2816 /* 2817 * Check if this child was a startup process. 2818 */ 2819 if (pid == StartupPID) 2820 { 2821 StartupPID = 0; 2822 2823 /* 2824 * Startup process exited in response to a shutdown request (or it 2825 * completed normally regardless of the shutdown request). 2826 */ 2827 if (Shutdown > NoShutdown && 2828 (EXIT_STATUS_0(exitstatus) || EXIT_STATUS_1(exitstatus))) 2829 { 2830 StartupStatus = STARTUP_NOT_RUNNING; 2831 pmState = PM_WAIT_BACKENDS; 2832 /* PostmasterStateMachine logic does the rest */ 2833 continue; 2834 } 2835 2836 if (EXIT_STATUS_3(exitstatus)) 2837 { 2838 ereport(LOG, 2839 (errmsg("shutdown at recovery target"))); 2840 StartupStatus = STARTUP_NOT_RUNNING; 2841 Shutdown = Max(Shutdown, SmartShutdown); 2842 TerminateChildren(SIGTERM); 2843 pmState = PM_WAIT_BACKENDS; 2844 /* PostmasterStateMachine logic does the rest */ 2845 continue; 2846 } 2847 2848 /* 2849 * Unexpected exit of startup process (including FATAL exit) 2850 * during PM_STARTUP is treated as catastrophic. There are no 2851 * other processes running yet, so we can just exit. 2852 */ 2853 if (pmState == PM_STARTUP && !EXIT_STATUS_0(exitstatus)) 2854 { 2855 LogChildExit(LOG, _("startup process"), 2856 pid, exitstatus); 2857 ereport(LOG, 2858 (errmsg("aborting startup due to startup process failure"))); 2859 ExitPostmaster(1); 2860 } 2861 2862 /* 2863 * After PM_STARTUP, any unexpected exit (including FATAL exit) of 2864 * the startup process is catastrophic, so kill other children, 2865 * and set StartupStatus so we don't try to reinitialize after 2866 * they're gone. Exception: if StartupStatus is STARTUP_SIGNALED, 2867 * then we previously sent the startup process a SIGQUIT; so 2868 * that's probably the reason it died, and we do want to try to 2869 * restart in that case. 2870 */ 2871 if (!EXIT_STATUS_0(exitstatus)) 2872 { 2873 if (StartupStatus == STARTUP_SIGNALED) 2874 StartupStatus = STARTUP_NOT_RUNNING; 2875 else 2876 StartupStatus = STARTUP_CRASHED; 2877 HandleChildCrash(pid, exitstatus, 2878 _("startup process")); 2879 continue; 2880 } 2881 2882 /* 2883 * Startup succeeded, commence normal operations 2884 */ 2885 StartupStatus = STARTUP_NOT_RUNNING; 2886 FatalError = false; 2887 Assert(AbortStartTime == 0); 2888 ReachedNormalRunning = true; 2889 pmState = PM_RUN; 2890 connsAllowed = ALLOW_ALL_CONNS; 2891 2892 /* 2893 * Crank up the background tasks, if we didn't do that already 2894 * when we entered consistent recovery state. It doesn't matter 2895 * if this fails, we'll just try again later. 2896 */ 2897 if (CheckpointerPID == 0) 2898 CheckpointerPID = StartCheckpointer(); 2899 if (BgWriterPID == 0) 2900 BgWriterPID = StartBackgroundWriter(); 2901 if (WalWriterPID == 0) 2902 WalWriterPID = StartWalWriter(); 2903 2904 /* 2905 * Likewise, start other special children as needed. In a restart 2906 * situation, some of them may be alive already. 2907 */ 2908 if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0) 2909 AutoVacPID = StartAutoVacLauncher(); 2910 if (PgArchStartupAllowed() && PgArchPID == 0) 2911 PgArchPID = pgarch_start(); 2912 if (PgStatPID == 0) 2913 PgStatPID = pgstat_start(); 2914 2915 /* workers may be scheduled to start now */ 2916 maybe_start_bgworkers(); 2917 2918 /* at this point we are really open for business */ 2919 ereport(LOG, 2920 (errmsg("database system is ready to accept connections"))); 2921 2922 /* Report status */ 2923 AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_READY); 2924 #ifdef USE_SYSTEMD 2925 sd_notify(0, "READY=1"); 2926 #endif 2927 2928 continue; 2929 } 2930 2931 /* 2932 * Was it the bgwriter? Normal exit can be ignored; we'll start a new 2933 * one at the next iteration of the postmaster's main loop, if 2934 * necessary. Any other exit condition is treated as a crash. 2935 */ 2936 if (pid == BgWriterPID) 2937 { 2938 BgWriterPID = 0; 2939 if (!EXIT_STATUS_0(exitstatus)) 2940 HandleChildCrash(pid, exitstatus, 2941 _("background writer process")); 2942 continue; 2943 } 2944 2945 /* 2946 * Was it the checkpointer? 2947 */ 2948 if (pid == CheckpointerPID) 2949 { 2950 CheckpointerPID = 0; 2951 if (EXIT_STATUS_0(exitstatus) && pmState == PM_SHUTDOWN) 2952 { 2953 /* 2954 * OK, we saw normal exit of the checkpointer after it's been 2955 * told to shut down. We expect that it wrote a shutdown 2956 * checkpoint. (If for some reason it didn't, recovery will 2957 * occur on next postmaster start.) 2958 * 2959 * At this point we should have no normal backend children 2960 * left (else we'd not be in PM_SHUTDOWN state) but we might 2961 * have dead_end children to wait for. 2962 * 2963 * If we have an archiver subprocess, tell it to do a last 2964 * archive cycle and quit. Likewise, if we have walsender 2965 * processes, tell them to send any remaining WAL and quit. 2966 */ 2967 Assert(Shutdown > NoShutdown); 2968 2969 /* Waken archiver for the last time */ 2970 if (PgArchPID != 0) 2971 signal_child(PgArchPID, SIGUSR2); 2972 2973 /* 2974 * Waken walsenders for the last time. No regular backends 2975 * should be around anymore. 2976 */ 2977 SignalChildren(SIGUSR2); 2978 2979 pmState = PM_SHUTDOWN_2; 2980 2981 /* 2982 * We can also shut down the stats collector now; there's 2983 * nothing left for it to do. 2984 */ 2985 if (PgStatPID != 0) 2986 signal_child(PgStatPID, SIGQUIT); 2987 } 2988 else 2989 { 2990 /* 2991 * Any unexpected exit of the checkpointer (including FATAL 2992 * exit) is treated as a crash. 2993 */ 2994 HandleChildCrash(pid, exitstatus, 2995 _("checkpointer process")); 2996 } 2997 2998 continue; 2999 } 3000 3001 /* 3002 * Was it the wal writer? Normal exit can be ignored; we'll start a 3003 * new one at the next iteration of the postmaster's main loop, if 3004 * necessary. Any other exit condition is treated as a crash. 3005 */ 3006 if (pid == WalWriterPID) 3007 { 3008 WalWriterPID = 0; 3009 if (!EXIT_STATUS_0(exitstatus)) 3010 HandleChildCrash(pid, exitstatus, 3011 _("WAL writer process")); 3012 continue; 3013 } 3014 3015 /* 3016 * Was it the wal receiver? If exit status is zero (normal) or one 3017 * (FATAL exit), we assume everything is all right just like normal 3018 * backends. (If we need a new wal receiver, we'll start one at the 3019 * next iteration of the postmaster's main loop.) 3020 */ 3021 if (pid == WalReceiverPID) 3022 { 3023 WalReceiverPID = 0; 3024 if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus)) 3025 HandleChildCrash(pid, exitstatus, 3026 _("WAL receiver process")); 3027 continue; 3028 } 3029 3030 /* 3031 * Was it the autovacuum launcher? Normal exit can be ignored; we'll 3032 * start a new one at the next iteration of the postmaster's main 3033 * loop, if necessary. Any other exit condition is treated as a 3034 * crash. 3035 */ 3036 if (pid == AutoVacPID) 3037 { 3038 AutoVacPID = 0; 3039 if (!EXIT_STATUS_0(exitstatus)) 3040 HandleChildCrash(pid, exitstatus, 3041 _("autovacuum launcher process")); 3042 continue; 3043 } 3044 3045 /* 3046 * Was it the archiver? If so, just try to start a new one; no need 3047 * to force reset of the rest of the system. (If fail, we'll try 3048 * again in future cycles of the main loop.). Unless we were waiting 3049 * for it to shut down; don't restart it in that case, and 3050 * PostmasterStateMachine() will advance to the next shutdown step. 3051 */ 3052 if (pid == PgArchPID) 3053 { 3054 PgArchPID = 0; 3055 if (!EXIT_STATUS_0(exitstatus)) 3056 LogChildExit(LOG, _("archiver process"), 3057 pid, exitstatus); 3058 if (PgArchStartupAllowed()) 3059 PgArchPID = pgarch_start(); 3060 continue; 3061 } 3062 3063 /* 3064 * Was it the statistics collector? If so, just try to start a new 3065 * one; no need to force reset of the rest of the system. (If fail, 3066 * we'll try again in future cycles of the main loop.) 3067 */ 3068 if (pid == PgStatPID) 3069 { 3070 PgStatPID = 0; 3071 if (!EXIT_STATUS_0(exitstatus)) 3072 LogChildExit(LOG, _("statistics collector process"), 3073 pid, exitstatus); 3074 if (pmState == PM_RUN || pmState == PM_HOT_STANDBY) 3075 PgStatPID = pgstat_start(); 3076 continue; 3077 } 3078 3079 /* Was it the system logger? If so, try to start a new one */ 3080 if (pid == SysLoggerPID) 3081 { 3082 SysLoggerPID = 0; 3083 /* for safety's sake, launch new logger *first* */ 3084 SysLoggerPID = SysLogger_Start(); 3085 if (!EXIT_STATUS_0(exitstatus)) 3086 LogChildExit(LOG, _("system logger process"), 3087 pid, exitstatus); 3088 continue; 3089 } 3090 3091 /* Was it one of our background workers? */ 3092 if (CleanupBackgroundWorker(pid, exitstatus)) 3093 { 3094 /* have it be restarted */ 3095 HaveCrashedWorker = true; 3096 continue; 3097 } 3098 3099 /* 3100 * Else do standard backend child cleanup. 3101 */ 3102 CleanupBackend(pid, exitstatus); 3103 } /* loop over pending child-death reports */ 3104 3105 /* 3106 * After cleaning out the SIGCHLD queue, see if we have any state changes 3107 * or actions to make. 3108 */ 3109 PostmasterStateMachine(); 3110 3111 /* Done with signal handler */ 3112 #ifdef WIN32 3113 PG_SETMASK(&UnBlockSig); 3114 #endif 3115 3116 errno = save_errno; 3117 } 3118 3119 /* 3120 * Scan the bgworkers list and see if the given PID (which has just stopped 3121 * or crashed) is in it. Handle its shutdown if so, and return true. If not a 3122 * bgworker, return false. 3123 * 3124 * This is heavily based on CleanupBackend. One important difference is that 3125 * we don't know yet that the dying process is a bgworker, so we must be silent 3126 * until we're sure it is. 3127 */ 3128 static bool 3129 CleanupBackgroundWorker(int pid, 3130 int exitstatus) /* child's exit status */ 3131 { 3132 char namebuf[MAXPGPATH]; 3133 slist_mutable_iter iter; 3134 3135 slist_foreach_modify(iter, &BackgroundWorkerList) 3136 { 3137 RegisteredBgWorker *rw; 3138 3139 rw = slist_container(RegisteredBgWorker, rw_lnode, iter.cur); 3140 3141 if (rw->rw_pid != pid) 3142 continue; 3143 3144 #ifdef WIN32 3145 /* see CleanupBackend */ 3146 if (exitstatus == ERROR_WAIT_NO_CHILDREN) 3147 exitstatus = 0; 3148 #endif 3149 3150 snprintf(namebuf, MAXPGPATH, _("background worker \"%s\""), 3151 rw->rw_worker.bgw_type); 3152 3153 3154 if (!EXIT_STATUS_0(exitstatus)) 3155 { 3156 /* Record timestamp, so we know when to restart the worker. */ 3157 rw->rw_crashed_at = GetCurrentTimestamp(); 3158 } 3159 else 3160 { 3161 /* Zero exit status means terminate */ 3162 rw->rw_crashed_at = 0; 3163 rw->rw_terminate = true; 3164 } 3165 3166 /* 3167 * Additionally, for shared-memory-connected workers, just like a 3168 * backend, any exit status other than 0 or 1 is considered a crash 3169 * and causes a system-wide restart. 3170 */ 3171 if ((rw->rw_worker.bgw_flags & BGWORKER_SHMEM_ACCESS) != 0) 3172 { 3173 if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus)) 3174 { 3175 HandleChildCrash(pid, exitstatus, namebuf); 3176 return true; 3177 } 3178 } 3179 3180 /* 3181 * We must release the postmaster child slot whether this worker is 3182 * connected to shared memory or not, but we only treat it as a crash 3183 * if it is in fact connected. 3184 */ 3185 if (!ReleasePostmasterChildSlot(rw->rw_child_slot) && 3186 (rw->rw_worker.bgw_flags & BGWORKER_SHMEM_ACCESS) != 0) 3187 { 3188 HandleChildCrash(pid, exitstatus, namebuf); 3189 return true; 3190 } 3191 3192 /* Get it out of the BackendList and clear out remaining data */ 3193 dlist_delete(&rw->rw_backend->elem); 3194 #ifdef EXEC_BACKEND 3195 ShmemBackendArrayRemove(rw->rw_backend); 3196 #endif 3197 3198 /* 3199 * It's possible that this background worker started some OTHER 3200 * background worker and asked to be notified when that worker started 3201 * or stopped. If so, cancel any notifications destined for the 3202 * now-dead backend. 3203 */ 3204 if (rw->rw_backend->bgworker_notify) 3205 BackgroundWorkerStopNotifications(rw->rw_pid); 3206 free(rw->rw_backend); 3207 rw->rw_backend = NULL; 3208 rw->rw_pid = 0; 3209 rw->rw_child_slot = 0; 3210 ReportBackgroundWorkerExit(&iter); /* report child death */ 3211 3212 LogChildExit(EXIT_STATUS_0(exitstatus) ? DEBUG1 : LOG, 3213 namebuf, pid, exitstatus); 3214 3215 return true; 3216 } 3217 3218 return false; 3219 } 3220 3221 /* 3222 * CleanupBackend -- cleanup after terminated backend. 3223 * 3224 * Remove all local state associated with backend. 3225 * 3226 * If you change this, see also CleanupBackgroundWorker. 3227 */ 3228 static void 3229 CleanupBackend(int pid, 3230 int exitstatus) /* child's exit status. */ 3231 { 3232 dlist_mutable_iter iter; 3233 3234 LogChildExit(DEBUG2, _("server process"), pid, exitstatus); 3235 3236 /* 3237 * If a backend dies in an ugly way then we must signal all other backends 3238 * to quickdie. If exit status is zero (normal) or one (FATAL exit), we 3239 * assume everything is all right and proceed to remove the backend from 3240 * the active backend list. 3241 */ 3242 3243 #ifdef WIN32 3244 3245 /* 3246 * On win32, also treat ERROR_WAIT_NO_CHILDREN (128) as nonfatal case, 3247 * since that sometimes happens under load when the process fails to start 3248 * properly (long before it starts using shared memory). Microsoft reports 3249 * it is related to mutex failure: 3250 * http://archives.postgresql.org/pgsql-hackers/2010-09/msg00790.php 3251 */ 3252 if (exitstatus == ERROR_WAIT_NO_CHILDREN) 3253 { 3254 LogChildExit(LOG, _("server process"), pid, exitstatus); 3255 exitstatus = 0; 3256 } 3257 #endif 3258 3259 if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus)) 3260 { 3261 HandleChildCrash(pid, exitstatus, _("server process")); 3262 return; 3263 } 3264 3265 dlist_foreach_modify(iter, &BackendList) 3266 { 3267 Backend *bp = dlist_container(Backend, elem, iter.cur); 3268 3269 if (bp->pid == pid) 3270 { 3271 if (!bp->dead_end) 3272 { 3273 if (!ReleasePostmasterChildSlot(bp->child_slot)) 3274 { 3275 /* 3276 * Uh-oh, the child failed to clean itself up. Treat as a 3277 * crash after all. 3278 */ 3279 HandleChildCrash(pid, exitstatus, _("server process")); 3280 return; 3281 } 3282 #ifdef EXEC_BACKEND 3283 ShmemBackendArrayRemove(bp); 3284 #endif 3285 } 3286 if (bp->bgworker_notify) 3287 { 3288 /* 3289 * This backend may have been slated to receive SIGUSR1 when 3290 * some background worker started or stopped. Cancel those 3291 * notifications, as we don't want to signal PIDs that are not 3292 * PostgreSQL backends. This gets skipped in the (probably 3293 * very common) case where the backend has never requested any 3294 * such notifications. 3295 */ 3296 BackgroundWorkerStopNotifications(bp->pid); 3297 } 3298 dlist_delete(iter.cur); 3299 free(bp); 3300 break; 3301 } 3302 } 3303 } 3304 3305 /* 3306 * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer, 3307 * walwriter, autovacuum, or background worker. 3308 * 3309 * The objectives here are to clean up our local state about the child 3310 * process, and to signal all other remaining children to quickdie. 3311 */ 3312 static void 3313 HandleChildCrash(int pid, int exitstatus, const char *procname) 3314 { 3315 dlist_mutable_iter iter; 3316 slist_iter siter; 3317 Backend *bp; 3318 bool take_action; 3319 3320 /* 3321 * We only log messages and send signals if this is the first process 3322 * crash and we're not doing an immediate shutdown; otherwise, we're only 3323 * here to update postmaster's idea of live processes. If we have already 3324 * signalled children, nonzero exit status is to be expected, so don't 3325 * clutter log. 3326 */ 3327 take_action = !FatalError && Shutdown != ImmediateShutdown; 3328 3329 if (take_action) 3330 { 3331 LogChildExit(LOG, procname, pid, exitstatus); 3332 ereport(LOG, 3333 (errmsg("terminating any other active server processes"))); 3334 } 3335 3336 /* Process background workers. */ 3337 slist_foreach(siter, &BackgroundWorkerList) 3338 { 3339 RegisteredBgWorker *rw; 3340 3341 rw = slist_container(RegisteredBgWorker, rw_lnode, siter.cur); 3342 if (rw->rw_pid == 0) 3343 continue; /* not running */ 3344 if (rw->rw_pid == pid) 3345 { 3346 /* 3347 * Found entry for freshly-dead worker, so remove it. 3348 */ 3349 (void) ReleasePostmasterChildSlot(rw->rw_child_slot); 3350 dlist_delete(&rw->rw_backend->elem); 3351 #ifdef EXEC_BACKEND 3352 ShmemBackendArrayRemove(rw->rw_backend); 3353 #endif 3354 free(rw->rw_backend); 3355 rw->rw_backend = NULL; 3356 rw->rw_pid = 0; 3357 rw->rw_child_slot = 0; 3358 /* don't reset crashed_at */ 3359 /* don't report child stop, either */ 3360 /* Keep looping so we can signal remaining workers */ 3361 } 3362 else 3363 { 3364 /* 3365 * This worker is still alive. Unless we did so already, tell it 3366 * to commit hara-kiri. 3367 * 3368 * SIGQUIT is the special signal that says exit without proc_exit 3369 * and let the user know what's going on. But if SendStop is set 3370 * (-s on command line), then we send SIGSTOP instead, so that we 3371 * can get core dumps from all backends by hand. 3372 */ 3373 if (take_action) 3374 { 3375 ereport(DEBUG2, 3376 (errmsg_internal("sending %s to process %d", 3377 (SendStop ? "SIGSTOP" : "SIGQUIT"), 3378 (int) rw->rw_pid))); 3379 signal_child(rw->rw_pid, (SendStop ? SIGSTOP : SIGQUIT)); 3380 } 3381 } 3382 } 3383 3384 /* Process regular backends */ 3385 dlist_foreach_modify(iter, &BackendList) 3386 { 3387 bp = dlist_container(Backend, elem, iter.cur); 3388 3389 if (bp->pid == pid) 3390 { 3391 /* 3392 * Found entry for freshly-dead backend, so remove it. 3393 */ 3394 if (!bp->dead_end) 3395 { 3396 (void) ReleasePostmasterChildSlot(bp->child_slot); 3397 #ifdef EXEC_BACKEND 3398 ShmemBackendArrayRemove(bp); 3399 #endif 3400 } 3401 dlist_delete(iter.cur); 3402 free(bp); 3403 /* Keep looping so we can signal remaining backends */ 3404 } 3405 else 3406 { 3407 /* 3408 * This backend is still alive. Unless we did so already, tell it 3409 * to commit hara-kiri. 3410 * 3411 * SIGQUIT is the special signal that says exit without proc_exit 3412 * and let the user know what's going on. But if SendStop is set 3413 * (-s on command line), then we send SIGSTOP instead, so that we 3414 * can get core dumps from all backends by hand. 3415 * 3416 * We could exclude dead_end children here, but at least in the 3417 * SIGSTOP case it seems better to include them. 3418 * 3419 * Background workers were already processed above; ignore them 3420 * here. 3421 */ 3422 if (bp->bkend_type == BACKEND_TYPE_BGWORKER) 3423 continue; 3424 3425 if (take_action) 3426 { 3427 ereport(DEBUG2, 3428 (errmsg_internal("sending %s to process %d", 3429 (SendStop ? "SIGSTOP" : "SIGQUIT"), 3430 (int) bp->pid))); 3431 signal_child(bp->pid, (SendStop ? SIGSTOP : SIGQUIT)); 3432 } 3433 } 3434 } 3435 3436 /* Take care of the startup process too */ 3437 if (pid == StartupPID) 3438 { 3439 StartupPID = 0; 3440 StartupStatus = STARTUP_CRASHED; 3441 } 3442 else if (StartupPID != 0 && take_action) 3443 { 3444 ereport(DEBUG2, 3445 (errmsg_internal("sending %s to process %d", 3446 (SendStop ? "SIGSTOP" : "SIGQUIT"), 3447 (int) StartupPID))); 3448 signal_child(StartupPID, (SendStop ? SIGSTOP : SIGQUIT)); 3449 StartupStatus = STARTUP_SIGNALED; 3450 } 3451 3452 /* Take care of the bgwriter too */ 3453 if (pid == BgWriterPID) 3454 BgWriterPID = 0; 3455 else if (BgWriterPID != 0 && take_action) 3456 { 3457 ereport(DEBUG2, 3458 (errmsg_internal("sending %s to process %d", 3459 (SendStop ? "SIGSTOP" : "SIGQUIT"), 3460 (int) BgWriterPID))); 3461 signal_child(BgWriterPID, (SendStop ? SIGSTOP : SIGQUIT)); 3462 } 3463 3464 /* Take care of the checkpointer too */ 3465 if (pid == CheckpointerPID) 3466 CheckpointerPID = 0; 3467 else if (CheckpointerPID != 0 && take_action) 3468 { 3469 ereport(DEBUG2, 3470 (errmsg_internal("sending %s to process %d", 3471 (SendStop ? "SIGSTOP" : "SIGQUIT"), 3472 (int) CheckpointerPID))); 3473 signal_child(CheckpointerPID, (SendStop ? SIGSTOP : SIGQUIT)); 3474 } 3475 3476 /* Take care of the walwriter too */ 3477 if (pid == WalWriterPID) 3478 WalWriterPID = 0; 3479 else if (WalWriterPID != 0 && take_action) 3480 { 3481 ereport(DEBUG2, 3482 (errmsg_internal("sending %s to process %d", 3483 (SendStop ? "SIGSTOP" : "SIGQUIT"), 3484 (int) WalWriterPID))); 3485 signal_child(WalWriterPID, (SendStop ? SIGSTOP : SIGQUIT)); 3486 } 3487 3488 /* Take care of the walreceiver too */ 3489 if (pid == WalReceiverPID) 3490 WalReceiverPID = 0; 3491 else if (WalReceiverPID != 0 && take_action) 3492 { 3493 ereport(DEBUG2, 3494 (errmsg_internal("sending %s to process %d", 3495 (SendStop ? "SIGSTOP" : "SIGQUIT"), 3496 (int) WalReceiverPID))); 3497 signal_child(WalReceiverPID, (SendStop ? SIGSTOP : SIGQUIT)); 3498 } 3499 3500 /* Take care of the autovacuum launcher too */ 3501 if (pid == AutoVacPID) 3502 AutoVacPID = 0; 3503 else if (AutoVacPID != 0 && take_action) 3504 { 3505 ereport(DEBUG2, 3506 (errmsg_internal("sending %s to process %d", 3507 (SendStop ? "SIGSTOP" : "SIGQUIT"), 3508 (int) AutoVacPID))); 3509 signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT)); 3510 } 3511 3512 /* 3513 * Force a power-cycle of the pgarch process too. (This isn't absolutely 3514 * necessary, but it seems like a good idea for robustness, and it 3515 * simplifies the state-machine logic in the case where a shutdown request 3516 * arrives during crash processing.) 3517 */ 3518 if (PgArchPID != 0 && take_action) 3519 { 3520 ereport(DEBUG2, 3521 (errmsg_internal("sending %s to process %d", 3522 "SIGQUIT", 3523 (int) PgArchPID))); 3524 signal_child(PgArchPID, SIGQUIT); 3525 } 3526 3527 /* 3528 * Force a power-cycle of the pgstat process too. (This isn't absolutely 3529 * necessary, but it seems like a good idea for robustness, and it 3530 * simplifies the state-machine logic in the case where a shutdown request 3531 * arrives during crash processing.) 3532 */ 3533 if (PgStatPID != 0 && take_action) 3534 { 3535 ereport(DEBUG2, 3536 (errmsg_internal("sending %s to process %d", 3537 "SIGQUIT", 3538 (int) PgStatPID))); 3539 signal_child(PgStatPID, SIGQUIT); 3540 allow_immediate_pgstat_restart(); 3541 } 3542 3543 /* We do NOT restart the syslogger */ 3544 3545 if (Shutdown != ImmediateShutdown) 3546 FatalError = true; 3547 3548 /* We now transit into a state of waiting for children to die */ 3549 if (pmState == PM_RECOVERY || 3550 pmState == PM_HOT_STANDBY || 3551 pmState == PM_RUN || 3552 pmState == PM_STOP_BACKENDS || 3553 pmState == PM_SHUTDOWN) 3554 pmState = PM_WAIT_BACKENDS; 3555 3556 /* 3557 * .. and if this doesn't happen quickly enough, now the clock is ticking 3558 * for us to kill them without mercy. 3559 */ 3560 if (AbortStartTime == 0) 3561 AbortStartTime = time(NULL); 3562 } 3563 3564 /* 3565 * Log the death of a child process. 3566 */ 3567 static void 3568 LogChildExit(int lev, const char *procname, int pid, int exitstatus) 3569 { 3570 /* 3571 * size of activity_buffer is arbitrary, but set equal to default 3572 * track_activity_query_size 3573 */ 3574 char activity_buffer[1024]; 3575 const char *activity = NULL; 3576 3577 if (!EXIT_STATUS_0(exitstatus)) 3578 activity = pgstat_get_crashed_backend_activity(pid, 3579 activity_buffer, 3580 sizeof(activity_buffer)); 3581 3582 if (WIFEXITED(exitstatus)) 3583 ereport(lev, 3584 3585 /*------ 3586 translator: %s is a noun phrase describing a child process, such as 3587 "server process" */ 3588 (errmsg("%s (PID %d) exited with exit code %d", 3589 procname, pid, WEXITSTATUS(exitstatus)), 3590 activity ? errdetail("Failed process was running: %s", activity) : 0)); 3591 else if (WIFSIGNALED(exitstatus)) 3592 { 3593 #if defined(WIN32) 3594 ereport(lev, 3595 3596 /*------ 3597 translator: %s is a noun phrase describing a child process, such as 3598 "server process" */ 3599 (errmsg("%s (PID %d) was terminated by exception 0x%X", 3600 procname, pid, WTERMSIG(exitstatus)), 3601 errhint("See C include file \"ntstatus.h\" for a description of the hexadecimal value."), 3602 activity ? errdetail("Failed process was running: %s", activity) : 0)); 3603 #else 3604 ereport(lev, 3605 3606 /*------ 3607 translator: %s is a noun phrase describing a child process, such as 3608 "server process" */ 3609 (errmsg("%s (PID %d) was terminated by signal %d: %s", 3610 procname, pid, WTERMSIG(exitstatus), 3611 pg_strsignal(WTERMSIG(exitstatus))), 3612 activity ? errdetail("Failed process was running: %s", activity) : 0)); 3613 #endif 3614 } 3615 else 3616 ereport(lev, 3617 3618 /*------ 3619 translator: %s is a noun phrase describing a child process, such as 3620 "server process" */ 3621 (errmsg("%s (PID %d) exited with unrecognized status %d", 3622 procname, pid, exitstatus), 3623 activity ? errdetail("Failed process was running: %s", activity) : 0)); 3624 } 3625 3626 /* 3627 * Advance the postmaster's state machine and take actions as appropriate 3628 * 3629 * This is common code for pmdie(), reaper() and sigusr1_handler(), which 3630 * receive the signals that might mean we need to change state. 3631 */ 3632 static void 3633 PostmasterStateMachine(void) 3634 { 3635 /* If we're doing a smart shutdown, try to advance that state. */ 3636 if (pmState == PM_RUN || pmState == PM_HOT_STANDBY) 3637 { 3638 if (connsAllowed == ALLOW_SUPERUSER_CONNS) 3639 { 3640 /* 3641 * ALLOW_SUPERUSER_CONNS state ends as soon as online backup mode 3642 * is not active. 3643 */ 3644 if (!BackupInProgress()) 3645 connsAllowed = ALLOW_NO_CONNS; 3646 } 3647 3648 if (connsAllowed == ALLOW_NO_CONNS) 3649 { 3650 /* 3651 * ALLOW_NO_CONNS state ends when we have no normal client 3652 * backends running. Then we're ready to stop other children. 3653 */ 3654 if (CountChildren(BACKEND_TYPE_NORMAL) == 0) 3655 pmState = PM_STOP_BACKENDS; 3656 } 3657 } 3658 3659 /* 3660 * If we're ready to do so, signal child processes to shut down. (This 3661 * isn't a persistent state, but treating it as a distinct pmState allows 3662 * us to share this code across multiple shutdown code paths.) 3663 */ 3664 if (pmState == PM_STOP_BACKENDS) 3665 { 3666 /* 3667 * Forget any pending requests for background workers, since we're no 3668 * longer willing to launch any new workers. (If additional requests 3669 * arrive, BackgroundWorkerStateChange will reject them.) 3670 */ 3671 ForgetUnstartedBackgroundWorkers(); 3672 3673 /* Signal all backend children except walsenders */ 3674 SignalSomeChildren(SIGTERM, 3675 BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND); 3676 /* and the autovac launcher too */ 3677 if (AutoVacPID != 0) 3678 signal_child(AutoVacPID, SIGTERM); 3679 /* and the bgwriter too */ 3680 if (BgWriterPID != 0) 3681 signal_child(BgWriterPID, SIGTERM); 3682 /* and the walwriter too */ 3683 if (WalWriterPID != 0) 3684 signal_child(WalWriterPID, SIGTERM); 3685 /* If we're in recovery, also stop startup and walreceiver procs */ 3686 if (StartupPID != 0) 3687 signal_child(StartupPID, SIGTERM); 3688 if (WalReceiverPID != 0) 3689 signal_child(WalReceiverPID, SIGTERM); 3690 /* checkpointer, archiver, stats, and syslogger may continue for now */ 3691 3692 /* Now transition to PM_WAIT_BACKENDS state to wait for them to die */ 3693 pmState = PM_WAIT_BACKENDS; 3694 } 3695 3696 /* 3697 * If we are in a state-machine state that implies waiting for backends to 3698 * exit, see if they're all gone, and change state if so. 3699 */ 3700 if (pmState == PM_WAIT_BACKENDS) 3701 { 3702 /* 3703 * PM_WAIT_BACKENDS state ends when we have no regular backends 3704 * (including autovac workers), no bgworkers (including unconnected 3705 * ones), and no walwriter, autovac launcher or bgwriter. If we are 3706 * doing crash recovery or an immediate shutdown then we expect the 3707 * checkpointer to exit as well, otherwise not. The archiver, stats, 3708 * and syslogger processes are disregarded since they are not 3709 * connected to shared memory; we also disregard dead_end children 3710 * here. Walsenders are also disregarded, they will be terminated 3711 * later after writing the checkpoint record, like the archiver 3712 * process. 3713 */ 3714 if (CountChildren(BACKEND_TYPE_ALL - BACKEND_TYPE_WALSND) == 0 && 3715 StartupPID == 0 && 3716 WalReceiverPID == 0 && 3717 BgWriterPID == 0 && 3718 (CheckpointerPID == 0 || 3719 (!FatalError && Shutdown < ImmediateShutdown)) && 3720 WalWriterPID == 0 && 3721 AutoVacPID == 0) 3722 { 3723 if (Shutdown >= ImmediateShutdown || FatalError) 3724 { 3725 /* 3726 * Start waiting for dead_end children to die. This state 3727 * change causes ServerLoop to stop creating new ones. 3728 */ 3729 pmState = PM_WAIT_DEAD_END; 3730 3731 /* 3732 * We already SIGQUIT'd the archiver and stats processes, if 3733 * any, when we started immediate shutdown or entered 3734 * FatalError state. 3735 */ 3736 } 3737 else 3738 { 3739 /* 3740 * If we get here, we are proceeding with normal shutdown. All 3741 * the regular children are gone, and it's time to tell the 3742 * checkpointer to do a shutdown checkpoint. 3743 */ 3744 Assert(Shutdown > NoShutdown); 3745 /* Start the checkpointer if not running */ 3746 if (CheckpointerPID == 0) 3747 CheckpointerPID = StartCheckpointer(); 3748 /* And tell it to shut down */ 3749 if (CheckpointerPID != 0) 3750 { 3751 signal_child(CheckpointerPID, SIGUSR2); 3752 pmState = PM_SHUTDOWN; 3753 } 3754 else 3755 { 3756 /* 3757 * If we failed to fork a checkpointer, just shut down. 3758 * Any required cleanup will happen at next restart. We 3759 * set FatalError so that an "abnormal shutdown" message 3760 * gets logged when we exit. 3761 */ 3762 FatalError = true; 3763 pmState = PM_WAIT_DEAD_END; 3764 3765 /* Kill the walsenders, archiver and stats collector too */ 3766 SignalChildren(SIGQUIT); 3767 if (PgArchPID != 0) 3768 signal_child(PgArchPID, SIGQUIT); 3769 if (PgStatPID != 0) 3770 signal_child(PgStatPID, SIGQUIT); 3771 } 3772 } 3773 } 3774 } 3775 3776 if (pmState == PM_SHUTDOWN_2) 3777 { 3778 /* 3779 * PM_SHUTDOWN_2 state ends when there's no other children than 3780 * dead_end children left. There shouldn't be any regular backends 3781 * left by now anyway; what we're really waiting for is walsenders and 3782 * archiver. 3783 */ 3784 if (PgArchPID == 0 && CountChildren(BACKEND_TYPE_ALL) == 0) 3785 { 3786 pmState = PM_WAIT_DEAD_END; 3787 } 3788 } 3789 3790 if (pmState == PM_WAIT_DEAD_END) 3791 { 3792 /* 3793 * PM_WAIT_DEAD_END state ends when the BackendList is entirely empty 3794 * (ie, no dead_end children remain), and the archiver and stats 3795 * collector are gone too. 3796 * 3797 * The reason we wait for those two is to protect them against a new 3798 * postmaster starting conflicting subprocesses; this isn't an 3799 * ironclad protection, but it at least helps in the 3800 * shutdown-and-immediately-restart scenario. Note that they have 3801 * already been sent appropriate shutdown signals, either during a 3802 * normal state transition leading up to PM_WAIT_DEAD_END, or during 3803 * FatalError processing. 3804 */ 3805 if (dlist_is_empty(&BackendList) && 3806 PgArchPID == 0 && PgStatPID == 0) 3807 { 3808 /* These other guys should be dead already */ 3809 Assert(StartupPID == 0); 3810 Assert(WalReceiverPID == 0); 3811 Assert(BgWriterPID == 0); 3812 Assert(CheckpointerPID == 0); 3813 Assert(WalWriterPID == 0); 3814 Assert(AutoVacPID == 0); 3815 /* syslogger is not considered here */ 3816 pmState = PM_NO_CHILDREN; 3817 } 3818 } 3819 3820 /* 3821 * If we've been told to shut down, we exit as soon as there are no 3822 * remaining children. If there was a crash, cleanup will occur at the 3823 * next startup. (Before PostgreSQL 8.3, we tried to recover from the 3824 * crash before exiting, but that seems unwise if we are quitting because 3825 * we got SIGTERM from init --- there may well not be time for recovery 3826 * before init decides to SIGKILL us.) 3827 * 3828 * Note that the syslogger continues to run. It will exit when it sees 3829 * EOF on its input pipe, which happens when there are no more upstream 3830 * processes. 3831 */ 3832 if (Shutdown > NoShutdown && pmState == PM_NO_CHILDREN) 3833 { 3834 if (FatalError) 3835 { 3836 ereport(LOG, (errmsg("abnormal database system shutdown"))); 3837 ExitPostmaster(1); 3838 } 3839 else 3840 { 3841 /* 3842 * Terminate exclusive backup mode to avoid recovery after a clean 3843 * fast shutdown. Since an exclusive backup can only be taken 3844 * during normal running (and not, for example, while running 3845 * under Hot Standby) it only makes sense to do this if we reached 3846 * normal running. If we're still in recovery, the backup file is 3847 * one we're recovering *from*, and we must keep it around so that 3848 * recovery restarts from the right place. 3849 */ 3850 if (ReachedNormalRunning) 3851 CancelBackup(); 3852 3853 /* Normal exit from the postmaster is here */ 3854 ExitPostmaster(0); 3855 } 3856 } 3857 3858 /* 3859 * If the startup process failed, or the user does not want an automatic 3860 * restart after backend crashes, wait for all non-syslogger children to 3861 * exit, and then exit postmaster. We don't try to reinitialize when the 3862 * startup process fails, because more than likely it will just fail again 3863 * and we will keep trying forever. 3864 */ 3865 if (pmState == PM_NO_CHILDREN && 3866 (StartupStatus == STARTUP_CRASHED || !restart_after_crash)) 3867 ExitPostmaster(1); 3868 3869 /* 3870 * If we need to recover from a crash, wait for all non-syslogger children 3871 * to exit, then reset shmem and StartupDataBase. 3872 */ 3873 if (FatalError && pmState == PM_NO_CHILDREN) 3874 { 3875 ereport(LOG, 3876 (errmsg("all server processes terminated; reinitializing"))); 3877 3878 /* allow background workers to immediately restart */ 3879 ResetBackgroundWorkerCrashTimes(); 3880 3881 shmem_exit(1); 3882 3883 /* re-read control file into local memory */ 3884 LocalProcessControlFile(true); 3885 3886 reset_shared(PostPortNumber); 3887 3888 StartupPID = StartupDataBase(); 3889 Assert(StartupPID != 0); 3890 StartupStatus = STARTUP_RUNNING; 3891 pmState = PM_STARTUP; 3892 /* crash recovery started, reset SIGKILL flag */ 3893 AbortStartTime = 0; 3894 } 3895 } 3896 3897 3898 /* 3899 * Send a signal to a postmaster child process 3900 * 3901 * On systems that have setsid(), each child process sets itself up as a 3902 * process group leader. For signals that are generally interpreted in the 3903 * appropriate fashion, we signal the entire process group not just the 3904 * direct child process. This allows us to, for example, SIGQUIT a blocked 3905 * archive_recovery script, or SIGINT a script being run by a backend via 3906 * system(). 3907 * 3908 * There is a race condition for recently-forked children: they might not 3909 * have executed setsid() yet. So we signal the child directly as well as 3910 * the group. We assume such a child will handle the signal before trying 3911 * to spawn any grandchild processes. We also assume that signaling the 3912 * child twice will not cause any problems. 3913 */ 3914 static void 3915 signal_child(pid_t pid, int signal) 3916 { 3917 if (kill(pid, signal) < 0) 3918 elog(DEBUG3, "kill(%ld,%d) failed: %m", (long) pid, signal); 3919 #ifdef HAVE_SETSID 3920 switch (signal) 3921 { 3922 case SIGINT: 3923 case SIGTERM: 3924 case SIGQUIT: 3925 case SIGSTOP: 3926 case SIGKILL: 3927 if (kill(-pid, signal) < 0) 3928 elog(DEBUG3, "kill(%ld,%d) failed: %m", (long) (-pid), signal); 3929 break; 3930 default: 3931 break; 3932 } 3933 #endif 3934 } 3935 3936 /* 3937 * Send a signal to the targeted children (but NOT special children; 3938 * dead_end children are never signaled, either). 3939 */ 3940 static bool 3941 SignalSomeChildren(int signal, int target) 3942 { 3943 dlist_iter iter; 3944 bool signaled = false; 3945 3946 dlist_foreach(iter, &BackendList) 3947 { 3948 Backend *bp = dlist_container(Backend, elem, iter.cur); 3949 3950 if (bp->dead_end) 3951 continue; 3952 3953 /* 3954 * Since target == BACKEND_TYPE_ALL is the most common case, we test 3955 * it first and avoid touching shared memory for every child. 3956 */ 3957 if (target != BACKEND_TYPE_ALL) 3958 { 3959 /* 3960 * Assign bkend_type for any recently announced WAL Sender 3961 * processes. 3962 */ 3963 if (bp->bkend_type == BACKEND_TYPE_NORMAL && 3964 IsPostmasterChildWalSender(bp->child_slot)) 3965 bp->bkend_type = BACKEND_TYPE_WALSND; 3966 3967 if (!(target & bp->bkend_type)) 3968 continue; 3969 } 3970 3971 ereport(DEBUG4, 3972 (errmsg_internal("sending signal %d to process %d", 3973 signal, (int) bp->pid))); 3974 signal_child(bp->pid, signal); 3975 signaled = true; 3976 } 3977 return signaled; 3978 } 3979 3980 /* 3981 * Send a termination signal to children. This considers all of our children 3982 * processes, except syslogger and dead_end backends. 3983 */ 3984 static void 3985 TerminateChildren(int signal) 3986 { 3987 SignalChildren(signal); 3988 if (StartupPID != 0) 3989 { 3990 signal_child(StartupPID, signal); 3991 if (signal == SIGQUIT || signal == SIGKILL) 3992 StartupStatus = STARTUP_SIGNALED; 3993 } 3994 if (BgWriterPID != 0) 3995 signal_child(BgWriterPID, signal); 3996 if (CheckpointerPID != 0) 3997 signal_child(CheckpointerPID, signal); 3998 if (WalWriterPID != 0) 3999 signal_child(WalWriterPID, signal); 4000 if (WalReceiverPID != 0) 4001 signal_child(WalReceiverPID, signal); 4002 if (AutoVacPID != 0) 4003 signal_child(AutoVacPID, signal); 4004 if (PgArchPID != 0) 4005 signal_child(PgArchPID, signal); 4006 if (PgStatPID != 0) 4007 signal_child(PgStatPID, signal); 4008 } 4009 4010 /* 4011 * BackendStartup -- start backend process 4012 * 4013 * returns: STATUS_ERROR if the fork failed, STATUS_OK otherwise. 4014 * 4015 * Note: if you change this code, also consider StartAutovacuumWorker. 4016 */ 4017 static int 4018 BackendStartup(Port *port) 4019 { 4020 Backend *bn; /* for backend cleanup */ 4021 pid_t pid; 4022 4023 /* 4024 * Create backend data structure. Better before the fork() so we can 4025 * handle failure cleanly. 4026 */ 4027 bn = (Backend *) malloc(sizeof(Backend)); 4028 if (!bn) 4029 { 4030 ereport(LOG, 4031 (errcode(ERRCODE_OUT_OF_MEMORY), 4032 errmsg("out of memory"))); 4033 return STATUS_ERROR; 4034 } 4035 4036 /* 4037 * Compute the cancel key that will be assigned to this backend. The 4038 * backend will have its own copy in the forked-off process' value of 4039 * MyCancelKey, so that it can transmit the key to the frontend. 4040 */ 4041 if (!RandomCancelKey(&MyCancelKey)) 4042 { 4043 free(bn); 4044 ereport(LOG, 4045 (errcode(ERRCODE_INTERNAL_ERROR), 4046 errmsg("could not generate random cancel key"))); 4047 return STATUS_ERROR; 4048 } 4049 4050 bn->cancel_key = MyCancelKey; 4051 4052 /* Pass down canAcceptConnections state */ 4053 port->canAcceptConnections = canAcceptConnections(BACKEND_TYPE_NORMAL); 4054 bn->dead_end = (port->canAcceptConnections != CAC_OK && 4055 port->canAcceptConnections != CAC_SUPERUSER); 4056 4057 /* 4058 * Unless it's a dead_end child, assign it a child slot number 4059 */ 4060 if (!bn->dead_end) 4061 bn->child_slot = MyPMChildSlot = AssignPostmasterChildSlot(); 4062 else 4063 bn->child_slot = 0; 4064 4065 /* Hasn't asked to be notified about any bgworkers yet */ 4066 bn->bgworker_notify = false; 4067 4068 #ifdef EXEC_BACKEND 4069 pid = backend_forkexec(port); 4070 #else /* !EXEC_BACKEND */ 4071 pid = fork_process(); 4072 if (pid == 0) /* child */ 4073 { 4074 free(bn); 4075 4076 /* Detangle from postmaster */ 4077 InitPostmasterChild(); 4078 4079 /* Close the postmaster's sockets */ 4080 ClosePostmasterPorts(false); 4081 4082 /* Perform additional initialization and collect startup packet */ 4083 BackendInitialize(port); 4084 4085 /* And run the backend */ 4086 BackendRun(port); 4087 } 4088 #endif /* EXEC_BACKEND */ 4089 4090 if (pid < 0) 4091 { 4092 /* in parent, fork failed */ 4093 int save_errno = errno; 4094 4095 if (!bn->dead_end) 4096 (void) ReleasePostmasterChildSlot(bn->child_slot); 4097 free(bn); 4098 errno = save_errno; 4099 ereport(LOG, 4100 (errmsg("could not fork new process for connection: %m"))); 4101 report_fork_failure_to_client(port, save_errno); 4102 return STATUS_ERROR; 4103 } 4104 4105 /* in parent, successful fork */ 4106 ereport(DEBUG2, 4107 (errmsg_internal("forked new backend, pid=%d socket=%d", 4108 (int) pid, (int) port->sock))); 4109 4110 /* 4111 * Everything's been successful, it's safe to add this backend to our list 4112 * of backends. 4113 */ 4114 bn->pid = pid; 4115 bn->bkend_type = BACKEND_TYPE_NORMAL; /* Can change later to WALSND */ 4116 dlist_push_head(&BackendList, &bn->elem); 4117 4118 #ifdef EXEC_BACKEND 4119 if (!bn->dead_end) 4120 ShmemBackendArrayAdd(bn); 4121 #endif 4122 4123 return STATUS_OK; 4124 } 4125 4126 /* 4127 * Try to report backend fork() failure to client before we close the 4128 * connection. Since we do not care to risk blocking the postmaster on 4129 * this connection, we set the connection to non-blocking and try only once. 4130 * 4131 * This is grungy special-purpose code; we cannot use backend libpq since 4132 * it's not up and running. 4133 */ 4134 static void 4135 report_fork_failure_to_client(Port *port, int errnum) 4136 { 4137 char buffer[1000]; 4138 int rc; 4139 4140 /* Format the error message packet (always V2 protocol) */ 4141 snprintf(buffer, sizeof(buffer), "E%s%s\n", 4142 _("could not fork new process for connection: "), 4143 strerror(errnum)); 4144 4145 /* Set port to non-blocking. Don't do send() if this fails */ 4146 if (!pg_set_noblock(port->sock)) 4147 return; 4148 4149 /* We'll retry after EINTR, but ignore all other failures */ 4150 do 4151 { 4152 rc = send(port->sock, buffer, strlen(buffer) + 1, 0); 4153 } while (rc < 0 && errno == EINTR); 4154 } 4155 4156 4157 /* 4158 * BackendInitialize -- initialize an interactive (postmaster-child) 4159 * backend process, and collect the client's startup packet. 4160 * 4161 * returns: nothing. Will not return at all if there's any failure. 4162 * 4163 * Note: this code does not depend on having any access to shared memory. 4164 * In the EXEC_BACKEND case, we are physically attached to shared memory 4165 * but have not yet set up most of our local pointers to shmem structures. 4166 */ 4167 static void 4168 BackendInitialize(Port *port) 4169 { 4170 int status; 4171 int ret; 4172 char remote_host[NI_MAXHOST]; 4173 char remote_port[NI_MAXSERV]; 4174 char remote_ps_data[NI_MAXHOST]; 4175 4176 /* Save port etc. for ps status */ 4177 MyProcPort = port; 4178 4179 /* 4180 * PreAuthDelay is a debugging aid for investigating problems in the 4181 * authentication cycle: it can be set in postgresql.conf to allow time to 4182 * attach to the newly-forked backend with a debugger. (See also 4183 * PostAuthDelay, which we allow clients to pass through PGOPTIONS, but it 4184 * is not honored until after authentication.) 4185 */ 4186 if (PreAuthDelay > 0) 4187 pg_usleep(PreAuthDelay * 1000000L); 4188 4189 /* This flag will remain set until InitPostgres finishes authentication */ 4190 ClientAuthInProgress = true; /* limit visibility of log messages */ 4191 4192 /* save process start time */ 4193 port->SessionStartTime = GetCurrentTimestamp(); 4194 MyStartTime = timestamptz_to_time_t(port->SessionStartTime); 4195 4196 /* set these to empty in case they are needed before we set them up */ 4197 port->remote_host = ""; 4198 port->remote_port = ""; 4199 4200 /* 4201 * Initialize libpq and enable reporting of ereport errors to the client. 4202 * Must do this now because authentication uses libpq to send messages. 4203 */ 4204 pq_init(); /* initialize libpq to talk to client */ 4205 whereToSendOutput = DestRemote; /* now safe to ereport to client */ 4206 4207 /* 4208 * We arrange to do proc_exit(1) if we receive SIGTERM or timeout while 4209 * trying to collect the startup packet; while SIGQUIT results in 4210 * _exit(2). Otherwise the postmaster cannot shutdown the database FAST 4211 * or IMMED cleanly if a buggy client fails to send the packet promptly. 4212 * 4213 * XXX this is pretty dangerous; signal handlers should not call anything 4214 * as complex as proc_exit() directly. We minimize the hazard by not 4215 * keeping these handlers active for longer than we must. However, it 4216 * seems necessary to be able to escape out of DNS lookups as well as the 4217 * startup packet reception proper, so we can't narrow the scope further 4218 * than is done here. 4219 * 4220 * XXX it follows that the remainder of this function must tolerate losing 4221 * control at any instant. Likewise, any pg_on_exit_callback registered 4222 * before or during this function must be prepared to execute at any 4223 * instant between here and the end of this function. Furthermore, 4224 * affected callbacks execute partially or not at all when a second 4225 * exit-inducing signal arrives after proc_exit_prepare() decrements 4226 * on_proc_exit_index. (Thanks to that mechanic, callbacks need not 4227 * anticipate more than one call.) This is fragile; it ought to instead 4228 * follow the norm of handling interrupts at selected, safe opportunities. 4229 */ 4230 pqsignal(SIGTERM, process_startup_packet_die); 4231 pqsignal(SIGQUIT, process_startup_packet_quickdie); 4232 InitializeTimeouts(); /* establishes SIGALRM handler */ 4233 PG_SETMASK(&StartupBlockSig); 4234 4235 /* 4236 * Get the remote host name and port for logging and status display. 4237 */ 4238 remote_host[0] = '\0'; 4239 remote_port[0] = '\0'; 4240 if ((ret = pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen, 4241 remote_host, sizeof(remote_host), 4242 remote_port, sizeof(remote_port), 4243 (log_hostname ? 0 : NI_NUMERICHOST) | NI_NUMERICSERV)) != 0) 4244 ereport(WARNING, 4245 (errmsg_internal("pg_getnameinfo_all() failed: %s", 4246 gai_strerror(ret)))); 4247 if (remote_port[0] == '\0') 4248 snprintf(remote_ps_data, sizeof(remote_ps_data), "%s", remote_host); 4249 else 4250 snprintf(remote_ps_data, sizeof(remote_ps_data), "%s(%s)", remote_host, remote_port); 4251 4252 /* 4253 * Save remote_host and remote_port in port structure (after this, they 4254 * will appear in log_line_prefix data for log messages). 4255 */ 4256 port->remote_host = strdup(remote_host); 4257 port->remote_port = strdup(remote_port); 4258 4259 /* And now we can issue the Log_connections message, if wanted */ 4260 if (Log_connections) 4261 { 4262 if (remote_port[0]) 4263 ereport(LOG, 4264 (errmsg("connection received: host=%s port=%s", 4265 remote_host, 4266 remote_port))); 4267 else 4268 ereport(LOG, 4269 (errmsg("connection received: host=%s", 4270 remote_host))); 4271 } 4272 4273 /* 4274 * If we did a reverse lookup to name, we might as well save the results 4275 * rather than possibly repeating the lookup during authentication. 4276 * 4277 * Note that we don't want to specify NI_NAMEREQD above, because then we'd 4278 * get nothing useful for a client without an rDNS entry. Therefore, we 4279 * must check whether we got a numeric IPv4 or IPv6 address, and not save 4280 * it into remote_hostname if so. (This test is conservative and might 4281 * sometimes classify a hostname as numeric, but an error in that 4282 * direction is safe; it only results in a possible extra lookup.) 4283 */ 4284 if (log_hostname && 4285 ret == 0 && 4286 strspn(remote_host, "0123456789.") < strlen(remote_host) && 4287 strspn(remote_host, "0123456789ABCDEFabcdef:") < strlen(remote_host)) 4288 port->remote_hostname = strdup(remote_host); 4289 4290 /* 4291 * Ready to begin client interaction. We will give up and proc_exit(1) 4292 * after a time delay, so that a broken client can't hog a connection 4293 * indefinitely. PreAuthDelay and any DNS interactions above don't count 4294 * against the time limit. 4295 * 4296 * Note: AuthenticationTimeout is applied here while waiting for the 4297 * startup packet, and then again in InitPostgres for the duration of any 4298 * authentication operations. So a hostile client could tie up the 4299 * process for nearly twice AuthenticationTimeout before we kick him off. 4300 * 4301 * Note: because PostgresMain will call InitializeTimeouts again, the 4302 * registration of STARTUP_PACKET_TIMEOUT will be lost. This is okay 4303 * since we never use it again after this function. 4304 */ 4305 RegisterTimeout(STARTUP_PACKET_TIMEOUT, StartupPacketTimeoutHandler); 4306 enable_timeout_after(STARTUP_PACKET_TIMEOUT, AuthenticationTimeout * 1000); 4307 4308 /* 4309 * Receive the startup packet (which might turn out to be a cancel request 4310 * packet). 4311 */ 4312 status = ProcessStartupPacket(port, false); 4313 4314 /* 4315 * Disable the timeout, and prevent SIGTERM/SIGQUIT again. 4316 */ 4317 disable_timeout(STARTUP_PACKET_TIMEOUT, false); 4318 PG_SETMASK(&BlockSig); 4319 4320 /* 4321 * Stop here if it was bad or a cancel packet. ProcessStartupPacket 4322 * already did any appropriate error reporting. 4323 */ 4324 if (status != STATUS_OK) 4325 proc_exit(0); 4326 4327 /* 4328 * Now that we have the user and database name, we can set the process 4329 * title for ps. It's good to do this as early as possible in startup. 4330 * 4331 * For a walsender, the ps display is set in the following form: 4332 * 4333 * postgres: walsender <user> <host> <activity> 4334 * 4335 * To achieve that, we pass "walsender" as username and username as dbname 4336 * to init_ps_display(). XXX: should add a new variant of 4337 * init_ps_display() to avoid abusing the parameters like this. 4338 */ 4339 if (am_walsender) 4340 init_ps_display(pgstat_get_backend_desc(B_WAL_SENDER), port->user_name, remote_ps_data, 4341 update_process_title ? "authentication" : ""); 4342 else 4343 init_ps_display(port->user_name, port->database_name, remote_ps_data, 4344 update_process_title ? "authentication" : ""); 4345 } 4346 4347 4348 /* 4349 * BackendRun -- set up the backend's argument list and invoke PostgresMain() 4350 * 4351 * returns: 4352 * Shouldn't return at all. 4353 * If PostgresMain() fails, return status. 4354 */ 4355 static void 4356 BackendRun(Port *port) 4357 { 4358 char **av; 4359 int maxac; 4360 int ac; 4361 long secs; 4362 int usecs; 4363 int i; 4364 4365 /* 4366 * Don't want backend to be able to see the postmaster random number 4367 * generator state. We have to clobber the static random_seed *and* start 4368 * a new random sequence in the random() library function. 4369 */ 4370 #ifndef HAVE_STRONG_RANDOM 4371 random_seed = 0; 4372 random_start_time.tv_usec = 0; 4373 #endif 4374 /* slightly hacky way to convert timestamptz into integers */ 4375 TimestampDifference(0, port->SessionStartTime, &secs, &usecs); 4376 srandom((unsigned int) (MyProcPid ^ (usecs << 12) ^ secs)); 4377 4378 /* 4379 * Now, build the argv vector that will be given to PostgresMain. 4380 * 4381 * The maximum possible number of commandline arguments that could come 4382 * from ExtraOptions is (strlen(ExtraOptions) + 1) / 2; see 4383 * pg_split_opts(). 4384 */ 4385 maxac = 2; /* for fixed args supplied below */ 4386 maxac += (strlen(ExtraOptions) + 1) / 2; 4387 4388 av = (char **) MemoryContextAlloc(TopMemoryContext, 4389 maxac * sizeof(char *)); 4390 ac = 0; 4391 4392 av[ac++] = "postgres"; 4393 4394 /* 4395 * Pass any backend switches specified with -o on the postmaster's own 4396 * command line. We assume these are secure. 4397 */ 4398 pg_split_opts(av, &ac, ExtraOptions); 4399 4400 av[ac] = NULL; 4401 4402 Assert(ac < maxac); 4403 4404 /* 4405 * Debug: print arguments being passed to backend 4406 */ 4407 ereport(DEBUG3, 4408 (errmsg_internal("%s child[%d]: starting with (", 4409 progname, (int) getpid()))); 4410 for (i = 0; i < ac; ++i) 4411 ereport(DEBUG3, 4412 (errmsg_internal("\t%s", av[i]))); 4413 ereport(DEBUG3, 4414 (errmsg_internal(")"))); 4415 4416 /* 4417 * Make sure we aren't in PostmasterContext anymore. (We can't delete it 4418 * just yet, though, because InitPostgres will need the HBA data.) 4419 */ 4420 MemoryContextSwitchTo(TopMemoryContext); 4421 4422 PostgresMain(ac, av, port->database_name, port->user_name); 4423 } 4424 4425 4426 #ifdef EXEC_BACKEND 4427 4428 /* 4429 * postmaster_forkexec -- fork and exec a postmaster subprocess 4430 * 4431 * The caller must have set up the argv array already, except for argv[2] 4432 * which will be filled with the name of the temp variable file. 4433 * 4434 * Returns the child process PID, or -1 on fork failure (a suitable error 4435 * message has been logged on failure). 4436 * 4437 * All uses of this routine will dispatch to SubPostmasterMain in the 4438 * child process. 4439 */ 4440 pid_t 4441 postmaster_forkexec(int argc, char *argv[]) 4442 { 4443 Port port; 4444 4445 /* This entry point passes dummy values for the Port variables */ 4446 memset(&port, 0, sizeof(port)); 4447 return internal_forkexec(argc, argv, &port); 4448 } 4449 4450 /* 4451 * backend_forkexec -- fork/exec off a backend process 4452 * 4453 * Some operating systems (WIN32) don't have fork() so we have to simulate 4454 * it by storing parameters that need to be passed to the child and 4455 * then create a new child process. 4456 * 4457 * returns the pid of the fork/exec'd process, or -1 on failure 4458 */ 4459 static pid_t 4460 backend_forkexec(Port *port) 4461 { 4462 char *av[4]; 4463 int ac = 0; 4464 4465 av[ac++] = "postgres"; 4466 av[ac++] = "--forkbackend"; 4467 av[ac++] = NULL; /* filled in by internal_forkexec */ 4468 4469 av[ac] = NULL; 4470 Assert(ac < lengthof(av)); 4471 4472 return internal_forkexec(ac, av, port); 4473 } 4474 4475 #ifndef WIN32 4476 4477 /* 4478 * internal_forkexec non-win32 implementation 4479 * 4480 * - writes out backend variables to the parameter file 4481 * - fork():s, and then exec():s the child process 4482 */ 4483 static pid_t 4484 internal_forkexec(int argc, char *argv[], Port *port) 4485 { 4486 static unsigned long tmpBackendFileNum = 0; 4487 pid_t pid; 4488 char tmpfilename[MAXPGPATH]; 4489 BackendParameters param; 4490 FILE *fp; 4491 4492 if (!save_backend_variables(¶m, port)) 4493 return -1; /* log made by save_backend_variables */ 4494 4495 /* Calculate name for temp file */ 4496 snprintf(tmpfilename, MAXPGPATH, "%s/%s.backend_var.%d.%lu", 4497 PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX, 4498 MyProcPid, ++tmpBackendFileNum); 4499 4500 /* Open file */ 4501 fp = AllocateFile(tmpfilename, PG_BINARY_W); 4502 if (!fp) 4503 { 4504 /* 4505 * As in OpenTemporaryFileInTablespace, try to make the temp-file 4506 * directory, ignoring errors. 4507 */ 4508 (void) MakePGDirectory(PG_TEMP_FILES_DIR); 4509 4510 fp = AllocateFile(tmpfilename, PG_BINARY_W); 4511 if (!fp) 4512 { 4513 ereport(LOG, 4514 (errcode_for_file_access(), 4515 errmsg("could not create file \"%s\": %m", 4516 tmpfilename))); 4517 return -1; 4518 } 4519 } 4520 4521 if (fwrite(¶m, sizeof(param), 1, fp) != 1) 4522 { 4523 ereport(LOG, 4524 (errcode_for_file_access(), 4525 errmsg("could not write to file \"%s\": %m", tmpfilename))); 4526 FreeFile(fp); 4527 return -1; 4528 } 4529 4530 /* Release file */ 4531 if (FreeFile(fp)) 4532 { 4533 ereport(LOG, 4534 (errcode_for_file_access(), 4535 errmsg("could not write to file \"%s\": %m", tmpfilename))); 4536 return -1; 4537 } 4538 4539 /* Make sure caller set up argv properly */ 4540 Assert(argc >= 3); 4541 Assert(argv[argc] == NULL); 4542 Assert(strncmp(argv[1], "--fork", 6) == 0); 4543 Assert(argv[2] == NULL); 4544 4545 /* Insert temp file name after --fork argument */ 4546 argv[2] = tmpfilename; 4547 4548 /* Fire off execv in child */ 4549 if ((pid = fork_process()) == 0) 4550 { 4551 if (execv(postgres_exec_path, argv) < 0) 4552 { 4553 ereport(LOG, 4554 (errmsg("could not execute server process \"%s\": %m", 4555 postgres_exec_path))); 4556 /* We're already in the child process here, can't return */ 4557 exit(1); 4558 } 4559 } 4560 4561 return pid; /* Parent returns pid, or -1 on fork failure */ 4562 } 4563 #else /* WIN32 */ 4564 4565 /* 4566 * internal_forkexec win32 implementation 4567 * 4568 * - starts backend using CreateProcess(), in suspended state 4569 * - writes out backend variables to the parameter file 4570 * - during this, duplicates handles and sockets required for 4571 * inheritance into the new process 4572 * - resumes execution of the new process once the backend parameter 4573 * file is complete. 4574 */ 4575 static pid_t 4576 internal_forkexec(int argc, char *argv[], Port *port) 4577 { 4578 int retry_count = 0; 4579 STARTUPINFO si; 4580 PROCESS_INFORMATION pi; 4581 int i; 4582 int j; 4583 char cmdLine[MAXPGPATH * 2]; 4584 HANDLE paramHandle; 4585 BackendParameters *param; 4586 SECURITY_ATTRIBUTES sa; 4587 char paramHandleStr[32]; 4588 win32_deadchild_waitinfo *childinfo; 4589 4590 /* Make sure caller set up argv properly */ 4591 Assert(argc >= 3); 4592 Assert(argv[argc] == NULL); 4593 Assert(strncmp(argv[1], "--fork", 6) == 0); 4594 Assert(argv[2] == NULL); 4595 4596 /* Resume here if we need to retry */ 4597 retry: 4598 4599 /* Set up shared memory for parameter passing */ 4600 ZeroMemory(&sa, sizeof(sa)); 4601 sa.nLength = sizeof(sa); 4602 sa.bInheritHandle = TRUE; 4603 paramHandle = CreateFileMapping(INVALID_HANDLE_VALUE, 4604 &sa, 4605 PAGE_READWRITE, 4606 0, 4607 sizeof(BackendParameters), 4608 NULL); 4609 if (paramHandle == INVALID_HANDLE_VALUE) 4610 { 4611 elog(LOG, "could not create backend parameter file mapping: error code %lu", 4612 GetLastError()); 4613 return -1; 4614 } 4615 4616 param = MapViewOfFile(paramHandle, FILE_MAP_WRITE, 0, 0, sizeof(BackendParameters)); 4617 if (!param) 4618 { 4619 elog(LOG, "could not map backend parameter memory: error code %lu", 4620 GetLastError()); 4621 CloseHandle(paramHandle); 4622 return -1; 4623 } 4624 4625 /* Insert temp file name after --fork argument */ 4626 #ifdef _WIN64 4627 sprintf(paramHandleStr, "%llu", (LONG_PTR) paramHandle); 4628 #else 4629 sprintf(paramHandleStr, "%lu", (DWORD) paramHandle); 4630 #endif 4631 argv[2] = paramHandleStr; 4632 4633 /* Format the cmd line */ 4634 cmdLine[sizeof(cmdLine) - 1] = '\0'; 4635 cmdLine[sizeof(cmdLine) - 2] = '\0'; 4636 snprintf(cmdLine, sizeof(cmdLine) - 1, "\"%s\"", postgres_exec_path); 4637 i = 0; 4638 while (argv[++i] != NULL) 4639 { 4640 j = strlen(cmdLine); 4641 snprintf(cmdLine + j, sizeof(cmdLine) - 1 - j, " \"%s\"", argv[i]); 4642 } 4643 if (cmdLine[sizeof(cmdLine) - 2] != '\0') 4644 { 4645 elog(LOG, "subprocess command line too long"); 4646 return -1; 4647 } 4648 4649 memset(&pi, 0, sizeof(pi)); 4650 memset(&si, 0, sizeof(si)); 4651 si.cb = sizeof(si); 4652 4653 /* 4654 * Create the subprocess in a suspended state. This will be resumed later, 4655 * once we have written out the parameter file. 4656 */ 4657 if (!CreateProcess(NULL, cmdLine, NULL, NULL, TRUE, CREATE_SUSPENDED, 4658 NULL, NULL, &si, &pi)) 4659 { 4660 elog(LOG, "CreateProcess call failed: %m (error code %lu)", 4661 GetLastError()); 4662 return -1; 4663 } 4664 4665 if (!save_backend_variables(param, port, pi.hProcess, pi.dwProcessId)) 4666 { 4667 /* 4668 * log made by save_backend_variables, but we have to clean up the 4669 * mess with the half-started process 4670 */ 4671 if (!TerminateProcess(pi.hProcess, 255)) 4672 ereport(LOG, 4673 (errmsg_internal("could not terminate unstarted process: error code %lu", 4674 GetLastError()))); 4675 CloseHandle(pi.hProcess); 4676 CloseHandle(pi.hThread); 4677 return -1; /* log made by save_backend_variables */ 4678 } 4679 4680 /* Drop the parameter shared memory that is now inherited to the backend */ 4681 if (!UnmapViewOfFile(param)) 4682 elog(LOG, "could not unmap view of backend parameter file: error code %lu", 4683 GetLastError()); 4684 if (!CloseHandle(paramHandle)) 4685 elog(LOG, "could not close handle to backend parameter file: error code %lu", 4686 GetLastError()); 4687 4688 /* 4689 * Reserve the memory region used by our main shared memory segment before 4690 * we resume the child process. Normally this should succeed, but if ASLR 4691 * is active then it might sometimes fail due to the stack or heap having 4692 * gotten mapped into that range. In that case, just terminate the 4693 * process and retry. 4694 */ 4695 if (!pgwin32_ReserveSharedMemoryRegion(pi.hProcess)) 4696 { 4697 /* pgwin32_ReserveSharedMemoryRegion already made a log entry */ 4698 if (!TerminateProcess(pi.hProcess, 255)) 4699 ereport(LOG, 4700 (errmsg_internal("could not terminate process that failed to reserve memory: error code %lu", 4701 GetLastError()))); 4702 CloseHandle(pi.hProcess); 4703 CloseHandle(pi.hThread); 4704 if (++retry_count < 100) 4705 goto retry; 4706 ereport(LOG, 4707 (errmsg("giving up after too many tries to reserve shared memory"), 4708 errhint("This might be caused by ASLR or antivirus software."))); 4709 return -1; 4710 } 4711 4712 /* 4713 * Now that the backend variables are written out, we start the child 4714 * thread so it can start initializing while we set up the rest of the 4715 * parent state. 4716 */ 4717 if (ResumeThread(pi.hThread) == -1) 4718 { 4719 if (!TerminateProcess(pi.hProcess, 255)) 4720 { 4721 ereport(LOG, 4722 (errmsg_internal("could not terminate unstartable process: error code %lu", 4723 GetLastError()))); 4724 CloseHandle(pi.hProcess); 4725 CloseHandle(pi.hThread); 4726 return -1; 4727 } 4728 CloseHandle(pi.hProcess); 4729 CloseHandle(pi.hThread); 4730 ereport(LOG, 4731 (errmsg_internal("could not resume thread of unstarted process: error code %lu", 4732 GetLastError()))); 4733 return -1; 4734 } 4735 4736 /* 4737 * Queue a waiter for to signal when this child dies. The wait will be 4738 * handled automatically by an operating system thread pool. 4739 * 4740 * Note: use malloc instead of palloc, since it needs to be thread-safe. 4741 * Struct will be free():d from the callback function that runs on a 4742 * different thread. 4743 */ 4744 childinfo = malloc(sizeof(win32_deadchild_waitinfo)); 4745 if (!childinfo) 4746 ereport(FATAL, 4747 (errcode(ERRCODE_OUT_OF_MEMORY), 4748 errmsg("out of memory"))); 4749 4750 childinfo->procHandle = pi.hProcess; 4751 childinfo->procId = pi.dwProcessId; 4752 4753 if (!RegisterWaitForSingleObject(&childinfo->waitHandle, 4754 pi.hProcess, 4755 pgwin32_deadchild_callback, 4756 childinfo, 4757 INFINITE, 4758 WT_EXECUTEONLYONCE | WT_EXECUTEINWAITTHREAD)) 4759 ereport(FATAL, 4760 (errmsg_internal("could not register process for wait: error code %lu", 4761 GetLastError()))); 4762 4763 /* Don't close pi.hProcess here - the wait thread needs access to it */ 4764 4765 CloseHandle(pi.hThread); 4766 4767 return pi.dwProcessId; 4768 } 4769 #endif /* WIN32 */ 4770 4771 4772 /* 4773 * SubPostmasterMain -- Get the fork/exec'd process into a state equivalent 4774 * to what it would be if we'd simply forked on Unix, and then 4775 * dispatch to the appropriate place. 4776 * 4777 * The first two command line arguments are expected to be "--forkFOO" 4778 * (where FOO indicates which postmaster child we are to become), and 4779 * the name of a variables file that we can read to load data that would 4780 * have been inherited by fork() on Unix. Remaining arguments go to the 4781 * subprocess FooMain() routine. 4782 */ 4783 void 4784 SubPostmasterMain(int argc, char *argv[]) 4785 { 4786 Port port; 4787 4788 /* In EXEC_BACKEND case we will not have inherited these settings */ 4789 IsPostmasterEnvironment = true; 4790 whereToSendOutput = DestNone; 4791 4792 /* Setup as postmaster child */ 4793 InitPostmasterChild(); 4794 4795 /* Setup essential subsystems (to ensure elog() behaves sanely) */ 4796 InitializeGUCOptions(); 4797 4798 /* Check we got appropriate args */ 4799 if (argc < 3) 4800 elog(FATAL, "invalid subpostmaster invocation"); 4801 4802 /* Read in the variables file */ 4803 memset(&port, 0, sizeof(Port)); 4804 read_backend_variables(argv[2], &port); 4805 4806 /* Close the postmaster's sockets (as soon as we know them) */ 4807 ClosePostmasterPorts(strcmp(argv[1], "--forklog") == 0); 4808 4809 /* 4810 * Set reference point for stack-depth checking 4811 */ 4812 set_stack_base(); 4813 4814 /* 4815 * Set up memory area for GSS information. Mirrors the code in ConnCreate 4816 * for the non-exec case. 4817 */ 4818 #if defined(ENABLE_GSS) || defined(ENABLE_SSPI) 4819 port.gss = (pg_gssinfo *) calloc(1, sizeof(pg_gssinfo)); 4820 if (!port.gss) 4821 ereport(FATAL, 4822 (errcode(ERRCODE_OUT_OF_MEMORY), 4823 errmsg("out of memory"))); 4824 #endif 4825 4826 /* 4827 * If appropriate, physically re-attach to shared memory segment. We want 4828 * to do this before going any further to ensure that we can attach at the 4829 * same address the postmaster used. On the other hand, if we choose not 4830 * to re-attach, we may have other cleanup to do. 4831 * 4832 * If testing EXEC_BACKEND on Linux, you should run this as root before 4833 * starting the postmaster: 4834 * 4835 * echo 0 >/proc/sys/kernel/randomize_va_space 4836 * 4837 * This prevents using randomized stack and code addresses that cause the 4838 * child process's memory map to be different from the parent's, making it 4839 * sometimes impossible to attach to shared memory at the desired address. 4840 * Return the setting to its old value (usually '1' or '2') when finished. 4841 */ 4842 if (strcmp(argv[1], "--forkbackend") == 0 || 4843 strcmp(argv[1], "--forkavlauncher") == 0 || 4844 strcmp(argv[1], "--forkavworker") == 0 || 4845 strcmp(argv[1], "--forkboot") == 0 || 4846 strncmp(argv[1], "--forkbgworker=", 15) == 0) 4847 PGSharedMemoryReAttach(); 4848 else 4849 PGSharedMemoryNoReAttach(); 4850 4851 /* autovacuum needs this set before calling InitProcess */ 4852 if (strcmp(argv[1], "--forkavlauncher") == 0) 4853 AutovacuumLauncherIAm(); 4854 if (strcmp(argv[1], "--forkavworker") == 0) 4855 AutovacuumWorkerIAm(); 4856 4857 /* 4858 * Start our win32 signal implementation. This has to be done after we 4859 * read the backend variables, because we need to pick up the signal pipe 4860 * from the parent process. 4861 */ 4862 #ifdef WIN32 4863 pgwin32_signal_initialize(); 4864 #endif 4865 4866 /* In EXEC_BACKEND case we will not have inherited these settings */ 4867 pqinitmask(); 4868 PG_SETMASK(&BlockSig); 4869 4870 /* Read in remaining GUC variables */ 4871 read_nondefault_variables(); 4872 4873 /* 4874 * Check that the data directory looks valid, which will also check the 4875 * privileges on the data directory and update our umask and file/group 4876 * variables for creating files later. Note: this should really be done 4877 * before we create any files or directories. 4878 */ 4879 checkDataDir(); 4880 4881 /* 4882 * (re-)read control file, as it contains config. The postmaster will 4883 * already have read this, but this process doesn't know about that. 4884 */ 4885 LocalProcessControlFile(false); 4886 4887 /* 4888 * Reload any libraries that were preloaded by the postmaster. Since we 4889 * exec'd this process, those libraries didn't come along with us; but we 4890 * should load them into all child processes to be consistent with the 4891 * non-EXEC_BACKEND behavior. 4892 */ 4893 process_shared_preload_libraries(); 4894 4895 /* Run backend or appropriate child */ 4896 if (strcmp(argv[1], "--forkbackend") == 0) 4897 { 4898 Assert(argc == 3); /* shouldn't be any more args */ 4899 4900 /* 4901 * Need to reinitialize the SSL library in the backend, since the 4902 * context structures contain function pointers and cannot be passed 4903 * through the parameter file. 4904 * 4905 * If for some reason reload fails (maybe the user installed broken 4906 * key files), soldier on without SSL; that's better than all 4907 * connections becoming impossible. 4908 * 4909 * XXX should we do this in all child processes? For the moment it's 4910 * enough to do it in backend children. 4911 */ 4912 #ifdef USE_SSL 4913 if (EnableSSL) 4914 { 4915 if (secure_initialize(false) == 0) 4916 LoadedSSL = true; 4917 else 4918 ereport(LOG, 4919 (errmsg("SSL configuration could not be loaded in child process"))); 4920 } 4921 #endif 4922 4923 /* 4924 * Perform additional initialization and collect startup packet. 4925 * 4926 * We want to do this before InitProcess() for a couple of reasons: 1. 4927 * so that we aren't eating up a PGPROC slot while waiting on the 4928 * client. 2. so that if InitProcess() fails due to being out of 4929 * PGPROC slots, we have already initialized libpq and are able to 4930 * report the error to the client. 4931 */ 4932 BackendInitialize(&port); 4933 4934 /* Restore basic shared memory pointers */ 4935 InitShmemAccess(UsedShmemSegAddr); 4936 4937 /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */ 4938 InitProcess(); 4939 4940 /* Attach process to shared data structures */ 4941 CreateSharedMemoryAndSemaphores(0); 4942 4943 /* And run the backend */ 4944 BackendRun(&port); /* does not return */ 4945 } 4946 if (strcmp(argv[1], "--forkboot") == 0) 4947 { 4948 /* Restore basic shared memory pointers */ 4949 InitShmemAccess(UsedShmemSegAddr); 4950 4951 /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */ 4952 InitAuxiliaryProcess(); 4953 4954 /* Attach process to shared data structures */ 4955 CreateSharedMemoryAndSemaphores(0); 4956 4957 AuxiliaryProcessMain(argc - 2, argv + 2); /* does not return */ 4958 } 4959 if (strcmp(argv[1], "--forkavlauncher") == 0) 4960 { 4961 /* Restore basic shared memory pointers */ 4962 InitShmemAccess(UsedShmemSegAddr); 4963 4964 /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */ 4965 InitProcess(); 4966 4967 /* Attach process to shared data structures */ 4968 CreateSharedMemoryAndSemaphores(0); 4969 4970 AutoVacLauncherMain(argc - 2, argv + 2); /* does not return */ 4971 } 4972 if (strcmp(argv[1], "--forkavworker") == 0) 4973 { 4974 /* Restore basic shared memory pointers */ 4975 InitShmemAccess(UsedShmemSegAddr); 4976 4977 /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */ 4978 InitProcess(); 4979 4980 /* Attach process to shared data structures */ 4981 CreateSharedMemoryAndSemaphores(0); 4982 4983 AutoVacWorkerMain(argc - 2, argv + 2); /* does not return */ 4984 } 4985 if (strncmp(argv[1], "--forkbgworker=", 15) == 0) 4986 { 4987 int shmem_slot; 4988 4989 /* do this as early as possible; in particular, before InitProcess() */ 4990 IsBackgroundWorker = true; 4991 4992 /* Restore basic shared memory pointers */ 4993 InitShmemAccess(UsedShmemSegAddr); 4994 4995 /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */ 4996 InitProcess(); 4997 4998 /* Attach process to shared data structures */ 4999 CreateSharedMemoryAndSemaphores(0); 5000 5001 /* Fetch MyBgworkerEntry from shared memory */ 5002 shmem_slot = atoi(argv[1] + 15); 5003 MyBgworkerEntry = BackgroundWorkerEntry(shmem_slot); 5004 5005 StartBackgroundWorker(); 5006 } 5007 if (strcmp(argv[1], "--forkarch") == 0) 5008 { 5009 /* Do not want to attach to shared memory */ 5010 5011 PgArchiverMain(argc, argv); /* does not return */ 5012 } 5013 if (strcmp(argv[1], "--forkcol") == 0) 5014 { 5015 /* Do not want to attach to shared memory */ 5016 5017 PgstatCollectorMain(argc, argv); /* does not return */ 5018 } 5019 if (strcmp(argv[1], "--forklog") == 0) 5020 { 5021 /* Do not want to attach to shared memory */ 5022 5023 SysLoggerMain(argc, argv); /* does not return */ 5024 } 5025 5026 abort(); /* shouldn't get here */ 5027 } 5028 #endif /* EXEC_BACKEND */ 5029 5030 5031 /* 5032 * ExitPostmaster -- cleanup 5033 * 5034 * Do NOT call exit() directly --- always go through here! 5035 */ 5036 static void 5037 ExitPostmaster(int status) 5038 { 5039 #ifdef HAVE_PTHREAD_IS_THREADED_NP 5040 5041 /* 5042 * There is no known cause for a postmaster to become multithreaded after 5043 * startup. Recheck to account for the possibility of unknown causes. 5044 * This message uses LOG level, because an unclean shutdown at this point 5045 * would usually not look much different from a clean shutdown. 5046 */ 5047 if (pthread_is_threaded_np() != 0) 5048 ereport(LOG, 5049 (errcode(ERRCODE_INTERNAL_ERROR), 5050 errmsg_internal("postmaster became multithreaded"), 5051 errdetail("Please report this to <pgsql-bugs@postgresql.org>."))); 5052 #endif 5053 5054 /* should cleanup shared memory and kill all backends */ 5055 5056 /* 5057 * Not sure of the semantics here. When the Postmaster dies, should the 5058 * backends all be killed? probably not. 5059 * 5060 * MUST -- vadim 05-10-1999 5061 */ 5062 5063 proc_exit(status); 5064 } 5065 5066 /* 5067 * sigusr1_handler - handle signal conditions from child processes 5068 */ 5069 static void 5070 sigusr1_handler(SIGNAL_ARGS) 5071 { 5072 int save_errno = errno; 5073 5074 /* 5075 * We rely on the signal mechanism to have blocked all signals ... except 5076 * on Windows, which lacks sigaction(), so we have to do it manually. 5077 */ 5078 #ifdef WIN32 5079 PG_SETMASK(&BlockSig); 5080 #endif 5081 5082 /* 5083 * RECOVERY_STARTED and BEGIN_HOT_STANDBY signals are ignored in 5084 * unexpected states. If the startup process quickly starts up, completes 5085 * recovery, exits, we might process the death of the startup process 5086 * first. We don't want to go back to recovery in that case. 5087 */ 5088 if (CheckPostmasterSignal(PMSIGNAL_RECOVERY_STARTED) && 5089 pmState == PM_STARTUP && Shutdown == NoShutdown) 5090 { 5091 /* WAL redo has started. We're out of reinitialization. */ 5092 FatalError = false; 5093 Assert(AbortStartTime == 0); 5094 5095 /* 5096 * Crank up the background tasks. It doesn't matter if this fails, 5097 * we'll just try again later. 5098 */ 5099 Assert(CheckpointerPID == 0); 5100 CheckpointerPID = StartCheckpointer(); 5101 Assert(BgWriterPID == 0); 5102 BgWriterPID = StartBackgroundWriter(); 5103 5104 /* 5105 * Start the archiver if we're responsible for (re-)archiving received 5106 * files. 5107 */ 5108 Assert(PgArchPID == 0); 5109 if (XLogArchivingAlways()) 5110 PgArchPID = pgarch_start(); 5111 5112 /* 5113 * If we aren't planning to enter hot standby mode later, treat 5114 * RECOVERY_STARTED as meaning we're out of startup, and report status 5115 * accordingly. 5116 */ 5117 if (!EnableHotStandby) 5118 { 5119 AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STANDBY); 5120 #ifdef USE_SYSTEMD 5121 sd_notify(0, "READY=1"); 5122 #endif 5123 } 5124 5125 pmState = PM_RECOVERY; 5126 } 5127 5128 if (CheckPostmasterSignal(PMSIGNAL_BEGIN_HOT_STANDBY) && 5129 pmState == PM_RECOVERY && Shutdown == NoShutdown) 5130 { 5131 /* 5132 * Likewise, start other special children as needed. 5133 */ 5134 Assert(PgStatPID == 0); 5135 PgStatPID = pgstat_start(); 5136 5137 ereport(LOG, 5138 (errmsg("database system is ready to accept read only connections"))); 5139 5140 /* Report status */ 5141 AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_READY); 5142 #ifdef USE_SYSTEMD 5143 sd_notify(0, "READY=1"); 5144 #endif 5145 5146 pmState = PM_HOT_STANDBY; 5147 connsAllowed = ALLOW_ALL_CONNS; 5148 5149 /* Some workers may be scheduled to start now */ 5150 StartWorkerNeeded = true; 5151 } 5152 5153 /* Process background worker state changes. */ 5154 if (CheckPostmasterSignal(PMSIGNAL_BACKGROUND_WORKER_CHANGE)) 5155 { 5156 /* Accept new worker requests only if not stopping. */ 5157 BackgroundWorkerStateChange(pmState < PM_STOP_BACKENDS); 5158 StartWorkerNeeded = true; 5159 } 5160 5161 if (StartWorkerNeeded || HaveCrashedWorker) 5162 maybe_start_bgworkers(); 5163 5164 if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) && 5165 PgArchPID != 0) 5166 { 5167 /* 5168 * Send SIGUSR1 to archiver process, to wake it up and begin archiving 5169 * next WAL file. 5170 */ 5171 signal_child(PgArchPID, SIGUSR1); 5172 } 5173 5174 if (CheckPostmasterSignal(PMSIGNAL_ROTATE_LOGFILE) && 5175 SysLoggerPID != 0) 5176 { 5177 /* Tell syslogger to rotate logfile */ 5178 signal_child(SysLoggerPID, SIGUSR1); 5179 } 5180 5181 if (CheckPostmasterSignal(PMSIGNAL_START_AUTOVAC_LAUNCHER) && 5182 Shutdown <= SmartShutdown && pmState < PM_STOP_BACKENDS) 5183 { 5184 /* 5185 * Start one iteration of the autovacuum daemon, even if autovacuuming 5186 * is nominally not enabled. This is so we can have an active defense 5187 * against transaction ID wraparound. We set a flag for the main loop 5188 * to do it rather than trying to do it here --- this is because the 5189 * autovac process itself may send the signal, and we want to handle 5190 * that by launching another iteration as soon as the current one 5191 * completes. 5192 */ 5193 start_autovac_launcher = true; 5194 } 5195 5196 if (CheckPostmasterSignal(PMSIGNAL_START_AUTOVAC_WORKER) && 5197 Shutdown <= SmartShutdown && pmState < PM_STOP_BACKENDS) 5198 { 5199 /* The autovacuum launcher wants us to start a worker process. */ 5200 StartAutovacuumWorker(); 5201 } 5202 5203 if (CheckPostmasterSignal(PMSIGNAL_START_WALRECEIVER)) 5204 { 5205 /* Startup Process wants us to start the walreceiver process. */ 5206 /* Start immediately if possible, else remember request for later. */ 5207 WalReceiverRequested = true; 5208 MaybeStartWalReceiver(); 5209 } 5210 5211 /* 5212 * Try to advance postmaster's state machine, if a child requests it. 5213 * 5214 * Be careful about the order of this action relative to sigusr1_handler's 5215 * other actions. Generally, this should be after other actions, in case 5216 * they have effects PostmasterStateMachine would need to know about. 5217 * However, we should do it before the CheckPromoteSignal step, which 5218 * cannot have any (immediate) effect on the state machine, but does 5219 * depend on what state we're in now. 5220 */ 5221 if (CheckPostmasterSignal(PMSIGNAL_ADVANCE_STATE_MACHINE)) 5222 { 5223 PostmasterStateMachine(); 5224 } 5225 5226 if (StartupPID != 0 && 5227 (pmState == PM_STARTUP || pmState == PM_RECOVERY || 5228 pmState == PM_HOT_STANDBY) && 5229 CheckPromoteSignal()) 5230 { 5231 /* Tell startup process to finish recovery */ 5232 signal_child(StartupPID, SIGUSR2); 5233 } 5234 5235 #ifdef WIN32 5236 PG_SETMASK(&UnBlockSig); 5237 #endif 5238 5239 errno = save_errno; 5240 } 5241 5242 /* 5243 * SIGTERM while processing startup packet. 5244 * Clean up and exit(1). 5245 * 5246 * Running proc_exit() from a signal handler is pretty unsafe, since we 5247 * can't know what code we've interrupted. But the alternative of using 5248 * _exit(2) is also unpalatable, since it'd mean that a "fast shutdown" 5249 * would cause a database crash cycle (forcing WAL replay at restart) 5250 * if any sessions are in authentication. So we live with it for now. 5251 * 5252 * One might be tempted to try to send a message indicating why we are 5253 * disconnecting. However, that would make this even more unsafe. Also, 5254 * it seems undesirable to provide clues about the database's state to 5255 * a client that has not yet completed authentication. 5256 */ 5257 static void 5258 process_startup_packet_die(SIGNAL_ARGS) 5259 { 5260 proc_exit(1); 5261 } 5262 5263 /* 5264 * SIGQUIT while processing startup packet. 5265 * 5266 * Some backend has bought the farm, 5267 * so we need to stop what we're doing and exit. 5268 */ 5269 static void 5270 process_startup_packet_quickdie(SIGNAL_ARGS) 5271 { 5272 /* 5273 * We DO NOT want to run proc_exit() or atexit() callbacks; they wouldn't 5274 * be safe to run from a signal handler. Just nail the windows shut and 5275 * get out of town. 5276 * 5277 * Note we do _exit(2) not _exit(1). This is to force the postmaster into 5278 * a system reset cycle if someone sends a manual SIGQUIT to a random 5279 * backend. (While it might be safe to do _exit(1), since this session 5280 * shouldn't have touched shared memory yet, there seems little point in 5281 * taking any risks.) 5282 */ 5283 _exit(2); 5284 } 5285 5286 /* 5287 * Dummy signal handler 5288 * 5289 * We use this for signals that we don't actually use in the postmaster, 5290 * but we do use in backends. If we were to SIG_IGN such signals in the 5291 * postmaster, then a newly started backend might drop a signal that arrives 5292 * before it's able to reconfigure its signal processing. (See notes in 5293 * tcop/postgres.c.) 5294 */ 5295 static void 5296 dummy_handler(SIGNAL_ARGS) 5297 { 5298 } 5299 5300 /* 5301 * Timeout while processing startup packet. 5302 * As for process_startup_packet_die(), we clean up and exit(1). 5303 * 5304 * This is theoretically just as hazardous as in process_startup_packet_die(), 5305 * although in practice we're almost certainly waiting for client input, 5306 * which greatly reduces the risk. 5307 */ 5308 static void 5309 StartupPacketTimeoutHandler(void) 5310 { 5311 proc_exit(1); 5312 } 5313 5314 5315 /* 5316 * Generate a random cancel key. 5317 */ 5318 static bool 5319 RandomCancelKey(int32 *cancel_key) 5320 { 5321 #ifdef HAVE_STRONG_RANDOM 5322 return pg_strong_random((char *) cancel_key, sizeof(int32)); 5323 #else 5324 5325 /* 5326 * If built with --disable-strong-random, use plain old erand48. 5327 * 5328 * We cannot use pg_backend_random() in postmaster, because it stores its 5329 * state in shared memory. 5330 */ 5331 static unsigned short seed[3]; 5332 5333 /* 5334 * Select a random seed at the time of first receiving a request. 5335 */ 5336 if (random_seed == 0) 5337 { 5338 struct timeval random_stop_time; 5339 5340 gettimeofday(&random_stop_time, NULL); 5341 5342 seed[0] = (unsigned short) random_start_time.tv_usec; 5343 seed[1] = (unsigned short) (random_stop_time.tv_usec) ^ (random_start_time.tv_usec >> 16); 5344 seed[2] = (unsigned short) (random_stop_time.tv_usec >> 16); 5345 5346 random_seed = 1; 5347 } 5348 5349 *cancel_key = pg_jrand48(seed); 5350 5351 return true; 5352 #endif 5353 } 5354 5355 /* 5356 * Count up number of child processes of specified types (dead_end children 5357 * are always excluded). 5358 */ 5359 static int 5360 CountChildren(int target) 5361 { 5362 dlist_iter iter; 5363 int cnt = 0; 5364 5365 dlist_foreach(iter, &BackendList) 5366 { 5367 Backend *bp = dlist_container(Backend, elem, iter.cur); 5368 5369 if (bp->dead_end) 5370 continue; 5371 5372 /* 5373 * Since target == BACKEND_TYPE_ALL is the most common case, we test 5374 * it first and avoid touching shared memory for every child. 5375 */ 5376 if (target != BACKEND_TYPE_ALL) 5377 { 5378 /* 5379 * Assign bkend_type for any recently announced WAL Sender 5380 * processes. 5381 */ 5382 if (bp->bkend_type == BACKEND_TYPE_NORMAL && 5383 IsPostmasterChildWalSender(bp->child_slot)) 5384 bp->bkend_type = BACKEND_TYPE_WALSND; 5385 5386 if (!(target & bp->bkend_type)) 5387 continue; 5388 } 5389 5390 cnt++; 5391 } 5392 return cnt; 5393 } 5394 5395 5396 /* 5397 * StartChildProcess -- start an auxiliary process for the postmaster 5398 * 5399 * "type" determines what kind of child will be started. All child types 5400 * initially go to AuxiliaryProcessMain, which will handle common setup. 5401 * 5402 * Return value of StartChildProcess is subprocess' PID, or 0 if failed 5403 * to start subprocess. 5404 */ 5405 static pid_t 5406 StartChildProcess(AuxProcType type) 5407 { 5408 pid_t pid; 5409 char *av[10]; 5410 int ac = 0; 5411 char typebuf[32]; 5412 5413 /* 5414 * Set up command-line arguments for subprocess 5415 */ 5416 av[ac++] = "postgres"; 5417 5418 #ifdef EXEC_BACKEND 5419 av[ac++] = "--forkboot"; 5420 av[ac++] = NULL; /* filled in by postmaster_forkexec */ 5421 #endif 5422 5423 snprintf(typebuf, sizeof(typebuf), "-x%d", type); 5424 av[ac++] = typebuf; 5425 5426 av[ac] = NULL; 5427 Assert(ac < lengthof(av)); 5428 5429 #ifdef EXEC_BACKEND 5430 pid = postmaster_forkexec(ac, av); 5431 #else /* !EXEC_BACKEND */ 5432 pid = fork_process(); 5433 5434 if (pid == 0) /* child */ 5435 { 5436 InitPostmasterChild(); 5437 5438 /* Close the postmaster's sockets */ 5439 ClosePostmasterPorts(false); 5440 5441 /* Release postmaster's working memory context */ 5442 MemoryContextSwitchTo(TopMemoryContext); 5443 MemoryContextDelete(PostmasterContext); 5444 PostmasterContext = NULL; 5445 5446 AuxiliaryProcessMain(ac, av); 5447 ExitPostmaster(0); 5448 } 5449 #endif /* EXEC_BACKEND */ 5450 5451 if (pid < 0) 5452 { 5453 /* in parent, fork failed */ 5454 int save_errno = errno; 5455 5456 errno = save_errno; 5457 switch (type) 5458 { 5459 case StartupProcess: 5460 ereport(LOG, 5461 (errmsg("could not fork startup process: %m"))); 5462 break; 5463 case BgWriterProcess: 5464 ereport(LOG, 5465 (errmsg("could not fork background writer process: %m"))); 5466 break; 5467 case CheckpointerProcess: 5468 ereport(LOG, 5469 (errmsg("could not fork checkpointer process: %m"))); 5470 break; 5471 case WalWriterProcess: 5472 ereport(LOG, 5473 (errmsg("could not fork WAL writer process: %m"))); 5474 break; 5475 case WalReceiverProcess: 5476 ereport(LOG, 5477 (errmsg("could not fork WAL receiver process: %m"))); 5478 break; 5479 default: 5480 ereport(LOG, 5481 (errmsg("could not fork process: %m"))); 5482 break; 5483 } 5484 5485 /* 5486 * fork failure is fatal during startup, but there's no need to choke 5487 * immediately if starting other child types fails. 5488 */ 5489 if (type == StartupProcess) 5490 ExitPostmaster(1); 5491 return 0; 5492 } 5493 5494 /* 5495 * in parent, successful fork 5496 */ 5497 return pid; 5498 } 5499 5500 /* 5501 * StartAutovacuumWorker 5502 * Start an autovac worker process. 5503 * 5504 * This function is here because it enters the resulting PID into the 5505 * postmaster's private backends list. 5506 * 5507 * NB -- this code very roughly matches BackendStartup. 5508 */ 5509 static void 5510 StartAutovacuumWorker(void) 5511 { 5512 Backend *bn; 5513 5514 /* 5515 * If not in condition to run a process, don't try, but handle it like a 5516 * fork failure. This does not normally happen, since the signal is only 5517 * supposed to be sent by autovacuum launcher when it's OK to do it, but 5518 * we have to check to avoid race-condition problems during DB state 5519 * changes. 5520 */ 5521 if (canAcceptConnections(BACKEND_TYPE_AUTOVAC) == CAC_OK) 5522 { 5523 /* 5524 * Compute the cancel key that will be assigned to this session. We 5525 * probably don't need cancel keys for autovac workers, but we'd 5526 * better have something random in the field to prevent unfriendly 5527 * people from sending cancels to them. 5528 */ 5529 if (!RandomCancelKey(&MyCancelKey)) 5530 { 5531 ereport(LOG, 5532 (errcode(ERRCODE_INTERNAL_ERROR), 5533 errmsg("could not generate random cancel key"))); 5534 return; 5535 } 5536 5537 bn = (Backend *) malloc(sizeof(Backend)); 5538 if (bn) 5539 { 5540 bn->cancel_key = MyCancelKey; 5541 5542 /* Autovac workers are not dead_end and need a child slot */ 5543 bn->dead_end = false; 5544 bn->child_slot = MyPMChildSlot = AssignPostmasterChildSlot(); 5545 bn->bgworker_notify = false; 5546 5547 bn->pid = StartAutoVacWorker(); 5548 if (bn->pid > 0) 5549 { 5550 bn->bkend_type = BACKEND_TYPE_AUTOVAC; 5551 dlist_push_head(&BackendList, &bn->elem); 5552 #ifdef EXEC_BACKEND 5553 ShmemBackendArrayAdd(bn); 5554 #endif 5555 /* all OK */ 5556 return; 5557 } 5558 5559 /* 5560 * fork failed, fall through to report -- actual error message was 5561 * logged by StartAutoVacWorker 5562 */ 5563 (void) ReleasePostmasterChildSlot(bn->child_slot); 5564 free(bn); 5565 } 5566 else 5567 ereport(LOG, 5568 (errcode(ERRCODE_OUT_OF_MEMORY), 5569 errmsg("out of memory"))); 5570 } 5571 5572 /* 5573 * Report the failure to the launcher, if it's running. (If it's not, we 5574 * might not even be connected to shared memory, so don't try to call 5575 * AutoVacWorkerFailed.) Note that we also need to signal it so that it 5576 * responds to the condition, but we don't do that here, instead waiting 5577 * for ServerLoop to do it. This way we avoid a ping-pong signalling in 5578 * quick succession between the autovac launcher and postmaster in case 5579 * things get ugly. 5580 */ 5581 if (AutoVacPID != 0) 5582 { 5583 AutoVacWorkerFailed(); 5584 avlauncher_needs_signal = true; 5585 } 5586 } 5587 5588 /* 5589 * MaybeStartWalReceiver 5590 * Start the WAL receiver process, if not running and our state allows. 5591 * 5592 * Note: if WalReceiverPID is already nonzero, it might seem that we should 5593 * clear WalReceiverRequested. However, there's a race condition if the 5594 * walreceiver terminates and the startup process immediately requests a new 5595 * one: it's quite possible to get the signal for the request before reaping 5596 * the dead walreceiver process. Better to risk launching an extra 5597 * walreceiver than to miss launching one we need. (The walreceiver code 5598 * has logic to recognize that it should go away if not needed.) 5599 */ 5600 static void 5601 MaybeStartWalReceiver(void) 5602 { 5603 if (WalReceiverPID == 0 && 5604 (pmState == PM_STARTUP || pmState == PM_RECOVERY || 5605 pmState == PM_HOT_STANDBY) && 5606 Shutdown <= SmartShutdown) 5607 { 5608 WalReceiverPID = StartWalReceiver(); 5609 if (WalReceiverPID != 0) 5610 WalReceiverRequested = false; 5611 /* else leave the flag set, so we'll try again later */ 5612 } 5613 } 5614 5615 5616 /* 5617 * Create the opts file 5618 */ 5619 static bool 5620 CreateOptsFile(int argc, char *argv[], char *fullprogname) 5621 { 5622 FILE *fp; 5623 int i; 5624 5625 #define OPTS_FILE "postmaster.opts" 5626 5627 if ((fp = fopen(OPTS_FILE, "w")) == NULL) 5628 { 5629 elog(LOG, "could not create file \"%s\": %m", OPTS_FILE); 5630 return false; 5631 } 5632 5633 fprintf(fp, "%s", fullprogname); 5634 for (i = 1; i < argc; i++) 5635 fprintf(fp, " \"%s\"", argv[i]); 5636 fputs("\n", fp); 5637 5638 if (fclose(fp)) 5639 { 5640 elog(LOG, "could not write file \"%s\": %m", OPTS_FILE); 5641 return false; 5642 } 5643 5644 return true; 5645 } 5646 5647 5648 /* 5649 * MaxLivePostmasterChildren 5650 * 5651 * This reports the number of entries needed in per-child-process arrays 5652 * (the PMChildFlags array, and if EXEC_BACKEND the ShmemBackendArray). 5653 * These arrays include regular backends, autovac workers, walsenders 5654 * and background workers, but not special children nor dead_end children. 5655 * This allows the arrays to have a fixed maximum size, to wit the same 5656 * too-many-children limit enforced by canAcceptConnections(). The exact value 5657 * isn't too critical as long as it's more than MaxBackends. 5658 */ 5659 int 5660 MaxLivePostmasterChildren(void) 5661 { 5662 return 2 * (MaxConnections + autovacuum_max_workers + 1 + 5663 max_worker_processes); 5664 } 5665 5666 /* 5667 * Connect background worker to a database. 5668 */ 5669 void 5670 BackgroundWorkerInitializeConnection(const char *dbname, const char *username, uint32 flags) 5671 { 5672 BackgroundWorker *worker = MyBgworkerEntry; 5673 5674 /* XXX is this the right errcode? */ 5675 if (!(worker->bgw_flags & BGWORKER_BACKEND_DATABASE_CONNECTION)) 5676 ereport(FATAL, 5677 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED), 5678 errmsg("database connection requirement not indicated during registration"))); 5679 5680 InitPostgres(dbname, InvalidOid, username, InvalidOid, NULL, (flags & BGWORKER_BYPASS_ALLOWCONN) != 0); 5681 5682 /* it had better not gotten out of "init" mode yet */ 5683 if (!IsInitProcessingMode()) 5684 ereport(ERROR, 5685 (errmsg("invalid processing mode in background worker"))); 5686 SetProcessingMode(NormalProcessing); 5687 } 5688 5689 /* 5690 * Connect background worker to a database using OIDs. 5691 */ 5692 void 5693 BackgroundWorkerInitializeConnectionByOid(Oid dboid, Oid useroid, uint32 flags) 5694 { 5695 BackgroundWorker *worker = MyBgworkerEntry; 5696 5697 /* XXX is this the right errcode? */ 5698 if (!(worker->bgw_flags & BGWORKER_BACKEND_DATABASE_CONNECTION)) 5699 ereport(FATAL, 5700 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED), 5701 errmsg("database connection requirement not indicated during registration"))); 5702 5703 InitPostgres(NULL, dboid, NULL, useroid, NULL, (flags & BGWORKER_BYPASS_ALLOWCONN) != 0); 5704 5705 /* it had better not gotten out of "init" mode yet */ 5706 if (!IsInitProcessingMode()) 5707 ereport(ERROR, 5708 (errmsg("invalid processing mode in background worker"))); 5709 SetProcessingMode(NormalProcessing); 5710 } 5711 5712 /* 5713 * Block/unblock signals in a background worker 5714 */ 5715 void 5716 BackgroundWorkerBlockSignals(void) 5717 { 5718 PG_SETMASK(&BlockSig); 5719 } 5720 5721 void 5722 BackgroundWorkerUnblockSignals(void) 5723 { 5724 PG_SETMASK(&UnBlockSig); 5725 } 5726 5727 #ifdef EXEC_BACKEND 5728 static pid_t 5729 bgworker_forkexec(int shmem_slot) 5730 { 5731 char *av[10]; 5732 int ac = 0; 5733 char forkav[MAXPGPATH]; 5734 5735 snprintf(forkav, MAXPGPATH, "--forkbgworker=%d", shmem_slot); 5736 5737 av[ac++] = "postgres"; 5738 av[ac++] = forkav; 5739 av[ac++] = NULL; /* filled in by postmaster_forkexec */ 5740 av[ac] = NULL; 5741 5742 Assert(ac < lengthof(av)); 5743 5744 return postmaster_forkexec(ac, av); 5745 } 5746 #endif 5747 5748 /* 5749 * Start a new bgworker. 5750 * Starting time conditions must have been checked already. 5751 * 5752 * Returns true on success, false on failure. 5753 * In either case, update the RegisteredBgWorker's state appropriately. 5754 * 5755 * This code is heavily based on autovacuum.c, q.v. 5756 */ 5757 static bool 5758 do_start_bgworker(RegisteredBgWorker *rw) 5759 { 5760 pid_t worker_pid; 5761 5762 Assert(rw->rw_pid == 0); 5763 5764 /* 5765 * Allocate and assign the Backend element. Note we must do this before 5766 * forking, so that we can handle failures (out of memory or child-process 5767 * slots) cleanly. 5768 * 5769 * Treat failure as though the worker had crashed. That way, the 5770 * postmaster will wait a bit before attempting to start it again; if we 5771 * tried again right away, most likely we'd find ourselves hitting the 5772 * same resource-exhaustion condition. 5773 */ 5774 if (!assign_backendlist_entry(rw)) 5775 { 5776 rw->rw_crashed_at = GetCurrentTimestamp(); 5777 return false; 5778 } 5779 5780 ereport(DEBUG1, 5781 (errmsg("starting background worker process \"%s\"", 5782 rw->rw_worker.bgw_name))); 5783 5784 #ifdef EXEC_BACKEND 5785 switch ((worker_pid = bgworker_forkexec(rw->rw_shmem_slot))) 5786 #else 5787 switch ((worker_pid = fork_process())) 5788 #endif 5789 { 5790 case -1: 5791 /* in postmaster, fork failed ... */ 5792 ereport(LOG, 5793 (errmsg("could not fork worker process: %m"))); 5794 /* undo what assign_backendlist_entry did */ 5795 ReleasePostmasterChildSlot(rw->rw_child_slot); 5796 rw->rw_child_slot = 0; 5797 free(rw->rw_backend); 5798 rw->rw_backend = NULL; 5799 /* mark entry as crashed, so we'll try again later */ 5800 rw->rw_crashed_at = GetCurrentTimestamp(); 5801 break; 5802 5803 #ifndef EXEC_BACKEND 5804 case 0: 5805 /* in postmaster child ... */ 5806 InitPostmasterChild(); 5807 5808 /* Close the postmaster's sockets */ 5809 ClosePostmasterPorts(false); 5810 5811 /* 5812 * Before blowing away PostmasterContext, save this bgworker's 5813 * data where it can find it. 5814 */ 5815 MyBgworkerEntry = (BackgroundWorker *) 5816 MemoryContextAlloc(TopMemoryContext, sizeof(BackgroundWorker)); 5817 memcpy(MyBgworkerEntry, &rw->rw_worker, sizeof(BackgroundWorker)); 5818 5819 /* Release postmaster's working memory context */ 5820 MemoryContextSwitchTo(TopMemoryContext); 5821 MemoryContextDelete(PostmasterContext); 5822 PostmasterContext = NULL; 5823 5824 StartBackgroundWorker(); 5825 5826 exit(1); /* should not get here */ 5827 break; 5828 #endif 5829 default: 5830 /* in postmaster, fork successful ... */ 5831 rw->rw_pid = worker_pid; 5832 rw->rw_backend->pid = rw->rw_pid; 5833 ReportBackgroundWorkerPID(rw); 5834 /* add new worker to lists of backends */ 5835 dlist_push_head(&BackendList, &rw->rw_backend->elem); 5836 #ifdef EXEC_BACKEND 5837 ShmemBackendArrayAdd(rw->rw_backend); 5838 #endif 5839 return true; 5840 } 5841 5842 return false; 5843 } 5844 5845 /* 5846 * Does the current postmaster state require starting a worker with the 5847 * specified start_time? 5848 */ 5849 static bool 5850 bgworker_should_start_now(BgWorkerStartTime start_time) 5851 { 5852 switch (pmState) 5853 { 5854 case PM_NO_CHILDREN: 5855 case PM_WAIT_DEAD_END: 5856 case PM_SHUTDOWN_2: 5857 case PM_SHUTDOWN: 5858 case PM_WAIT_BACKENDS: 5859 case PM_STOP_BACKENDS: 5860 break; 5861 5862 case PM_RUN: 5863 if (start_time == BgWorkerStart_RecoveryFinished) 5864 return true; 5865 /* fall through */ 5866 5867 case PM_HOT_STANDBY: 5868 if (start_time == BgWorkerStart_ConsistentState) 5869 return true; 5870 /* fall through */ 5871 5872 case PM_RECOVERY: 5873 case PM_STARTUP: 5874 case PM_INIT: 5875 if (start_time == BgWorkerStart_PostmasterStart) 5876 return true; 5877 /* fall through */ 5878 5879 } 5880 5881 return false; 5882 } 5883 5884 /* 5885 * Allocate the Backend struct for a connected background worker, but don't 5886 * add it to the list of backends just yet. 5887 * 5888 * On failure, return false without changing any worker state. 5889 * 5890 * Some info from the Backend is copied into the passed rw. 5891 */ 5892 static bool 5893 assign_backendlist_entry(RegisteredBgWorker *rw) 5894 { 5895 Backend *bn; 5896 5897 /* 5898 * Check that database state allows another connection. Currently the 5899 * only possible failure is CAC_TOOMANY, so we just log an error message 5900 * based on that rather than checking the error code precisely. 5901 */ 5902 if (canAcceptConnections(BACKEND_TYPE_BGWORKER) != CAC_OK) 5903 { 5904 ereport(LOG, 5905 (errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED), 5906 errmsg("no slot available for new worker process"))); 5907 return false; 5908 } 5909 5910 /* 5911 * Compute the cancel key that will be assigned to this session. We 5912 * probably don't need cancel keys for background workers, but we'd better 5913 * have something random in the field to prevent unfriendly people from 5914 * sending cancels to them. 5915 */ 5916 if (!RandomCancelKey(&MyCancelKey)) 5917 { 5918 ereport(LOG, 5919 (errcode(ERRCODE_INTERNAL_ERROR), 5920 errmsg("could not generate random cancel key"))); 5921 return false; 5922 } 5923 5924 bn = malloc(sizeof(Backend)); 5925 if (bn == NULL) 5926 { 5927 ereport(LOG, 5928 (errcode(ERRCODE_OUT_OF_MEMORY), 5929 errmsg("out of memory"))); 5930 return false; 5931 } 5932 5933 bn->cancel_key = MyCancelKey; 5934 bn->child_slot = MyPMChildSlot = AssignPostmasterChildSlot(); 5935 bn->bkend_type = BACKEND_TYPE_BGWORKER; 5936 bn->dead_end = false; 5937 bn->bgworker_notify = false; 5938 5939 rw->rw_backend = bn; 5940 rw->rw_child_slot = bn->child_slot; 5941 5942 return true; 5943 } 5944 5945 /* 5946 * If the time is right, start background worker(s). 5947 * 5948 * As a side effect, the bgworker control variables are set or reset 5949 * depending on whether more workers may need to be started. 5950 * 5951 * We limit the number of workers started per call, to avoid consuming the 5952 * postmaster's attention for too long when many such requests are pending. 5953 * As long as StartWorkerNeeded is true, ServerLoop will not block and will 5954 * call this function again after dealing with any other issues. 5955 */ 5956 static void 5957 maybe_start_bgworkers(void) 5958 { 5959 #define MAX_BGWORKERS_TO_LAUNCH 100 5960 int num_launched = 0; 5961 TimestampTz now = 0; 5962 slist_mutable_iter iter; 5963 5964 /* 5965 * During crash recovery, we have no need to be called until the state 5966 * transition out of recovery. 5967 */ 5968 if (FatalError) 5969 { 5970 StartWorkerNeeded = false; 5971 HaveCrashedWorker = false; 5972 return; 5973 } 5974 5975 /* Don't need to be called again unless we find a reason for it below */ 5976 StartWorkerNeeded = false; 5977 HaveCrashedWorker = false; 5978 5979 slist_foreach_modify(iter, &BackgroundWorkerList) 5980 { 5981 RegisteredBgWorker *rw; 5982 5983 rw = slist_container(RegisteredBgWorker, rw_lnode, iter.cur); 5984 5985 /* ignore if already running */ 5986 if (rw->rw_pid != 0) 5987 continue; 5988 5989 /* if marked for death, clean up and remove from list */ 5990 if (rw->rw_terminate) 5991 { 5992 ForgetBackgroundWorker(&iter); 5993 continue; 5994 } 5995 5996 /* 5997 * If this worker has crashed previously, maybe it needs to be 5998 * restarted (unless on registration it specified it doesn't want to 5999 * be restarted at all). Check how long ago did a crash last happen. 6000 * If the last crash is too recent, don't start it right away; let it 6001 * be restarted once enough time has passed. 6002 */ 6003 if (rw->rw_crashed_at != 0) 6004 { 6005 if (rw->rw_worker.bgw_restart_time == BGW_NEVER_RESTART) 6006 { 6007 int notify_pid; 6008 6009 notify_pid = rw->rw_worker.bgw_notify_pid; 6010 6011 ForgetBackgroundWorker(&iter); 6012 6013 /* Report worker is gone now. */ 6014 if (notify_pid != 0) 6015 kill(notify_pid, SIGUSR1); 6016 6017 continue; 6018 } 6019 6020 /* read system time only when needed */ 6021 if (now == 0) 6022 now = GetCurrentTimestamp(); 6023 6024 if (!TimestampDifferenceExceeds(rw->rw_crashed_at, now, 6025 rw->rw_worker.bgw_restart_time * 1000)) 6026 { 6027 /* Set flag to remember that we have workers to start later */ 6028 HaveCrashedWorker = true; 6029 continue; 6030 } 6031 } 6032 6033 if (bgworker_should_start_now(rw->rw_worker.bgw_start_time)) 6034 { 6035 /* reset crash time before trying to start worker */ 6036 rw->rw_crashed_at = 0; 6037 6038 /* 6039 * Try to start the worker. 6040 * 6041 * On failure, give up processing workers for now, but set 6042 * StartWorkerNeeded so we'll come back here on the next iteration 6043 * of ServerLoop to try again. (We don't want to wait, because 6044 * there might be additional ready-to-run workers.) We could set 6045 * HaveCrashedWorker as well, since this worker is now marked 6046 * crashed, but there's no need because the next run of this 6047 * function will do that. 6048 */ 6049 if (!do_start_bgworker(rw)) 6050 { 6051 StartWorkerNeeded = true; 6052 return; 6053 } 6054 6055 /* 6056 * If we've launched as many workers as allowed, quit, but have 6057 * ServerLoop call us again to look for additional ready-to-run 6058 * workers. There might not be any, but we'll find out the next 6059 * time we run. 6060 */ 6061 if (++num_launched >= MAX_BGWORKERS_TO_LAUNCH) 6062 { 6063 StartWorkerNeeded = true; 6064 return; 6065 } 6066 } 6067 } 6068 } 6069 6070 /* 6071 * When a backend asks to be notified about worker state changes, we 6072 * set a flag in its backend entry. The background worker machinery needs 6073 * to know when such backends exit. 6074 */ 6075 bool 6076 PostmasterMarkPIDForWorkerNotify(int pid) 6077 { 6078 dlist_iter iter; 6079 Backend *bp; 6080 6081 dlist_foreach(iter, &BackendList) 6082 { 6083 bp = dlist_container(Backend, elem, iter.cur); 6084 if (bp->pid == pid) 6085 { 6086 bp->bgworker_notify = true; 6087 return true; 6088 } 6089 } 6090 return false; 6091 } 6092 6093 #ifdef EXEC_BACKEND 6094 6095 /* 6096 * The following need to be available to the save/restore_backend_variables 6097 * functions. They are marked NON_EXEC_STATIC in their home modules. 6098 */ 6099 extern slock_t *ShmemLock; 6100 extern slock_t *ProcStructLock; 6101 extern PGPROC *AuxiliaryProcs; 6102 extern PMSignalData *PMSignalState; 6103 extern pgsocket pgStatSock; 6104 extern pg_time_t first_syslogger_file_time; 6105 6106 #ifndef WIN32 6107 #define write_inheritable_socket(dest, src, childpid) ((*(dest) = (src)), true) 6108 #define read_inheritable_socket(dest, src) (*(dest) = *(src)) 6109 #else 6110 static bool write_duplicated_handle(HANDLE *dest, HANDLE src, HANDLE child); 6111 static bool write_inheritable_socket(InheritableSocket *dest, SOCKET src, 6112 pid_t childPid); 6113 static void read_inheritable_socket(SOCKET *dest, InheritableSocket *src); 6114 #endif 6115 6116 6117 /* Save critical backend variables into the BackendParameters struct */ 6118 #ifndef WIN32 6119 static bool 6120 save_backend_variables(BackendParameters *param, Port *port) 6121 #else 6122 static bool 6123 save_backend_variables(BackendParameters *param, Port *port, 6124 HANDLE childProcess, pid_t childPid) 6125 #endif 6126 { 6127 memcpy(¶m->port, port, sizeof(Port)); 6128 if (!write_inheritable_socket(¶m->portsocket, port->sock, childPid)) 6129 return false; 6130 6131 strlcpy(param->DataDir, DataDir, MAXPGPATH); 6132 6133 memcpy(¶m->ListenSocket, &ListenSocket, sizeof(ListenSocket)); 6134 6135 param->MyCancelKey = MyCancelKey; 6136 param->MyPMChildSlot = MyPMChildSlot; 6137 6138 #ifdef WIN32 6139 param->ShmemProtectiveRegion = ShmemProtectiveRegion; 6140 #endif 6141 param->UsedShmemSegID = UsedShmemSegID; 6142 param->UsedShmemSegAddr = UsedShmemSegAddr; 6143 6144 param->ShmemLock = ShmemLock; 6145 param->ShmemVariableCache = ShmemVariableCache; 6146 param->ShmemBackendArray = ShmemBackendArray; 6147 6148 #ifndef HAVE_SPINLOCKS 6149 param->SpinlockSemaArray = SpinlockSemaArray; 6150 #endif 6151 param->NamedLWLockTrancheRequests = NamedLWLockTrancheRequests; 6152 param->NamedLWLockTrancheArray = NamedLWLockTrancheArray; 6153 param->MainLWLockArray = MainLWLockArray; 6154 param->ProcStructLock = ProcStructLock; 6155 param->ProcGlobal = ProcGlobal; 6156 param->AuxiliaryProcs = AuxiliaryProcs; 6157 param->PreparedXactProcs = PreparedXactProcs; 6158 param->PMSignalState = PMSignalState; 6159 if (!write_inheritable_socket(¶m->pgStatSock, pgStatSock, childPid)) 6160 return false; 6161 6162 param->PostmasterPid = PostmasterPid; 6163 param->PgStartTime = PgStartTime; 6164 param->PgReloadTime = PgReloadTime; 6165 param->first_syslogger_file_time = first_syslogger_file_time; 6166 6167 param->redirection_done = redirection_done; 6168 param->IsBinaryUpgrade = IsBinaryUpgrade; 6169 param->max_safe_fds = max_safe_fds; 6170 6171 param->MaxBackends = MaxBackends; 6172 6173 #ifdef WIN32 6174 param->PostmasterHandle = PostmasterHandle; 6175 if (!write_duplicated_handle(¶m->initial_signal_pipe, 6176 pgwin32_create_signal_listener(childPid), 6177 childProcess)) 6178 return false; 6179 #else 6180 memcpy(¶m->postmaster_alive_fds, &postmaster_alive_fds, 6181 sizeof(postmaster_alive_fds)); 6182 #endif 6183 6184 memcpy(¶m->syslogPipe, &syslogPipe, sizeof(syslogPipe)); 6185 6186 strlcpy(param->my_exec_path, my_exec_path, MAXPGPATH); 6187 6188 strlcpy(param->pkglib_path, pkglib_path, MAXPGPATH); 6189 6190 strlcpy(param->ExtraOptions, ExtraOptions, MAXPGPATH); 6191 6192 return true; 6193 } 6194 6195 6196 #ifdef WIN32 6197 /* 6198 * Duplicate a handle for usage in a child process, and write the child 6199 * process instance of the handle to the parameter file. 6200 */ 6201 static bool 6202 write_duplicated_handle(HANDLE *dest, HANDLE src, HANDLE childProcess) 6203 { 6204 HANDLE hChild = INVALID_HANDLE_VALUE; 6205 6206 if (!DuplicateHandle(GetCurrentProcess(), 6207 src, 6208 childProcess, 6209 &hChild, 6210 0, 6211 TRUE, 6212 DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS)) 6213 { 6214 ereport(LOG, 6215 (errmsg_internal("could not duplicate handle to be written to backend parameter file: error code %lu", 6216 GetLastError()))); 6217 return false; 6218 } 6219 6220 *dest = hChild; 6221 return true; 6222 } 6223 6224 /* 6225 * Duplicate a socket for usage in a child process, and write the resulting 6226 * structure to the parameter file. 6227 * This is required because a number of LSPs (Layered Service Providers) very 6228 * common on Windows (antivirus, firewalls, download managers etc) break 6229 * straight socket inheritance. 6230 */ 6231 static bool 6232 write_inheritable_socket(InheritableSocket *dest, SOCKET src, pid_t childpid) 6233 { 6234 dest->origsocket = src; 6235 if (src != 0 && src != PGINVALID_SOCKET) 6236 { 6237 /* Actual socket */ 6238 if (WSADuplicateSocket(src, childpid, &dest->wsainfo) != 0) 6239 { 6240 ereport(LOG, 6241 (errmsg("could not duplicate socket %d for use in backend: error code %d", 6242 (int) src, WSAGetLastError()))); 6243 return false; 6244 } 6245 } 6246 return true; 6247 } 6248 6249 /* 6250 * Read a duplicate socket structure back, and get the socket descriptor. 6251 */ 6252 static void 6253 read_inheritable_socket(SOCKET *dest, InheritableSocket *src) 6254 { 6255 SOCKET s; 6256 6257 if (src->origsocket == PGINVALID_SOCKET || src->origsocket == 0) 6258 { 6259 /* Not a real socket! */ 6260 *dest = src->origsocket; 6261 } 6262 else 6263 { 6264 /* Actual socket, so create from structure */ 6265 s = WSASocket(FROM_PROTOCOL_INFO, 6266 FROM_PROTOCOL_INFO, 6267 FROM_PROTOCOL_INFO, 6268 &src->wsainfo, 6269 0, 6270 0); 6271 if (s == INVALID_SOCKET) 6272 { 6273 write_stderr("could not create inherited socket: error code %d\n", 6274 WSAGetLastError()); 6275 exit(1); 6276 } 6277 *dest = s; 6278 6279 /* 6280 * To make sure we don't get two references to the same socket, close 6281 * the original one. (This would happen when inheritance actually 6282 * works.. 6283 */ 6284 closesocket(src->origsocket); 6285 } 6286 } 6287 #endif 6288 6289 static void 6290 read_backend_variables(char *id, Port *port) 6291 { 6292 BackendParameters param; 6293 6294 #ifndef WIN32 6295 /* Non-win32 implementation reads from file */ 6296 FILE *fp; 6297 6298 /* Open file */ 6299 fp = AllocateFile(id, PG_BINARY_R); 6300 if (!fp) 6301 { 6302 write_stderr("could not open backend variables file \"%s\": %s\n", 6303 id, strerror(errno)); 6304 exit(1); 6305 } 6306 6307 if (fread(¶m, sizeof(param), 1, fp) != 1) 6308 { 6309 write_stderr("could not read from backend variables file \"%s\": %s\n", 6310 id, strerror(errno)); 6311 exit(1); 6312 } 6313 6314 /* Release file */ 6315 FreeFile(fp); 6316 if (unlink(id) != 0) 6317 { 6318 write_stderr("could not remove file \"%s\": %s\n", 6319 id, strerror(errno)); 6320 exit(1); 6321 } 6322 #else 6323 /* Win32 version uses mapped file */ 6324 HANDLE paramHandle; 6325 BackendParameters *paramp; 6326 6327 #ifdef _WIN64 6328 paramHandle = (HANDLE) _atoi64(id); 6329 #else 6330 paramHandle = (HANDLE) atol(id); 6331 #endif 6332 paramp = MapViewOfFile(paramHandle, FILE_MAP_READ, 0, 0, 0); 6333 if (!paramp) 6334 { 6335 write_stderr("could not map view of backend variables: error code %lu\n", 6336 GetLastError()); 6337 exit(1); 6338 } 6339 6340 memcpy(¶m, paramp, sizeof(BackendParameters)); 6341 6342 if (!UnmapViewOfFile(paramp)) 6343 { 6344 write_stderr("could not unmap view of backend variables: error code %lu\n", 6345 GetLastError()); 6346 exit(1); 6347 } 6348 6349 if (!CloseHandle(paramHandle)) 6350 { 6351 write_stderr("could not close handle to backend parameter variables: error code %lu\n", 6352 GetLastError()); 6353 exit(1); 6354 } 6355 #endif 6356 6357 restore_backend_variables(¶m, port); 6358 } 6359 6360 /* Restore critical backend variables from the BackendParameters struct */ 6361 static void 6362 restore_backend_variables(BackendParameters *param, Port *port) 6363 { 6364 memcpy(port, ¶m->port, sizeof(Port)); 6365 read_inheritable_socket(&port->sock, ¶m->portsocket); 6366 6367 SetDataDir(param->DataDir); 6368 6369 memcpy(&ListenSocket, ¶m->ListenSocket, sizeof(ListenSocket)); 6370 6371 MyCancelKey = param->MyCancelKey; 6372 MyPMChildSlot = param->MyPMChildSlot; 6373 6374 #ifdef WIN32 6375 ShmemProtectiveRegion = param->ShmemProtectiveRegion; 6376 #endif 6377 UsedShmemSegID = param->UsedShmemSegID; 6378 UsedShmemSegAddr = param->UsedShmemSegAddr; 6379 6380 ShmemLock = param->ShmemLock; 6381 ShmemVariableCache = param->ShmemVariableCache; 6382 ShmemBackendArray = param->ShmemBackendArray; 6383 6384 #ifndef HAVE_SPINLOCKS 6385 SpinlockSemaArray = param->SpinlockSemaArray; 6386 #endif 6387 NamedLWLockTrancheRequests = param->NamedLWLockTrancheRequests; 6388 NamedLWLockTrancheArray = param->NamedLWLockTrancheArray; 6389 MainLWLockArray = param->MainLWLockArray; 6390 ProcStructLock = param->ProcStructLock; 6391 ProcGlobal = param->ProcGlobal; 6392 AuxiliaryProcs = param->AuxiliaryProcs; 6393 PreparedXactProcs = param->PreparedXactProcs; 6394 PMSignalState = param->PMSignalState; 6395 read_inheritable_socket(&pgStatSock, ¶m->pgStatSock); 6396 6397 PostmasterPid = param->PostmasterPid; 6398 PgStartTime = param->PgStartTime; 6399 PgReloadTime = param->PgReloadTime; 6400 first_syslogger_file_time = param->first_syslogger_file_time; 6401 6402 redirection_done = param->redirection_done; 6403 IsBinaryUpgrade = param->IsBinaryUpgrade; 6404 max_safe_fds = param->max_safe_fds; 6405 6406 MaxBackends = param->MaxBackends; 6407 6408 #ifdef WIN32 6409 PostmasterHandle = param->PostmasterHandle; 6410 pgwin32_initial_signal_pipe = param->initial_signal_pipe; 6411 #else 6412 memcpy(&postmaster_alive_fds, ¶m->postmaster_alive_fds, 6413 sizeof(postmaster_alive_fds)); 6414 #endif 6415 6416 memcpy(&syslogPipe, ¶m->syslogPipe, sizeof(syslogPipe)); 6417 6418 strlcpy(my_exec_path, param->my_exec_path, MAXPGPATH); 6419 6420 strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH); 6421 6422 strlcpy(ExtraOptions, param->ExtraOptions, MAXPGPATH); 6423 } 6424 6425 6426 Size 6427 ShmemBackendArraySize(void) 6428 { 6429 return mul_size(MaxLivePostmasterChildren(), sizeof(Backend)); 6430 } 6431 6432 void 6433 ShmemBackendArrayAllocation(void) 6434 { 6435 Size size = ShmemBackendArraySize(); 6436 6437 ShmemBackendArray = (Backend *) ShmemAlloc(size); 6438 /* Mark all slots as empty */ 6439 memset(ShmemBackendArray, 0, size); 6440 } 6441 6442 static void 6443 ShmemBackendArrayAdd(Backend *bn) 6444 { 6445 /* The array slot corresponding to my PMChildSlot should be free */ 6446 int i = bn->child_slot - 1; 6447 6448 Assert(ShmemBackendArray[i].pid == 0); 6449 ShmemBackendArray[i] = *bn; 6450 } 6451 6452 static void 6453 ShmemBackendArrayRemove(Backend *bn) 6454 { 6455 int i = bn->child_slot - 1; 6456 6457 Assert(ShmemBackendArray[i].pid == bn->pid); 6458 /* Mark the slot as empty */ 6459 ShmemBackendArray[i].pid = 0; 6460 } 6461 #endif /* EXEC_BACKEND */ 6462 6463 6464 #ifdef WIN32 6465 6466 /* 6467 * Subset implementation of waitpid() for Windows. We assume pid is -1 6468 * (that is, check all child processes) and options is WNOHANG (don't wait). 6469 */ 6470 static pid_t 6471 waitpid(pid_t pid, int *exitstatus, int options) 6472 { 6473 DWORD dwd; 6474 ULONG_PTR key; 6475 OVERLAPPED *ovl; 6476 6477 /* 6478 * Check if there are any dead children. If there are, return the pid of 6479 * the first one that died. 6480 */ 6481 if (GetQueuedCompletionStatus(win32ChildQueue, &dwd, &key, &ovl, 0)) 6482 { 6483 *exitstatus = (int) key; 6484 return dwd; 6485 } 6486 6487 return -1; 6488 } 6489 6490 /* 6491 * Note! Code below executes on a thread pool! All operations must 6492 * be thread safe! Note that elog() and friends must *not* be used. 6493 */ 6494 static void WINAPI 6495 pgwin32_deadchild_callback(PVOID lpParameter, BOOLEAN TimerOrWaitFired) 6496 { 6497 win32_deadchild_waitinfo *childinfo = (win32_deadchild_waitinfo *) lpParameter; 6498 DWORD exitcode; 6499 6500 if (TimerOrWaitFired) 6501 return; /* timeout. Should never happen, since we use 6502 * INFINITE as timeout value. */ 6503 6504 /* 6505 * Remove handle from wait - required even though it's set to wait only 6506 * once 6507 */ 6508 UnregisterWaitEx(childinfo->waitHandle, NULL); 6509 6510 if (!GetExitCodeProcess(childinfo->procHandle, &exitcode)) 6511 { 6512 /* 6513 * Should never happen. Inform user and set a fixed exitcode. 6514 */ 6515 write_stderr("could not read exit code for process\n"); 6516 exitcode = 255; 6517 } 6518 6519 if (!PostQueuedCompletionStatus(win32ChildQueue, childinfo->procId, (ULONG_PTR) exitcode, NULL)) 6520 write_stderr("could not post child completion status\n"); 6521 6522 /* 6523 * Handle is per-process, so we close it here instead of in the 6524 * originating thread 6525 */ 6526 CloseHandle(childinfo->procHandle); 6527 6528 /* 6529 * Free struct that was allocated before the call to 6530 * RegisterWaitForSingleObject() 6531 */ 6532 free(childinfo); 6533 6534 /* Queue SIGCHLD signal */ 6535 pg_queue_signal(SIGCHLD); 6536 } 6537 #endif /* WIN32 */ 6538 6539 /* 6540 * Initialize one and only handle for monitoring postmaster death. 6541 * 6542 * Called once in the postmaster, so that child processes can subsequently 6543 * monitor if their parent is dead. 6544 */ 6545 static void 6546 InitPostmasterDeathWatchHandle(void) 6547 { 6548 #ifndef WIN32 6549 6550 /* 6551 * Create a pipe. Postmaster holds the write end of the pipe open 6552 * (POSTMASTER_FD_OWN), and children hold the read end. Children can pass 6553 * the read file descriptor to select() to wake up in case postmaster 6554 * dies, or check for postmaster death with a (read() == 0). Children must 6555 * close the write end as soon as possible after forking, because EOF 6556 * won't be signaled in the read end until all processes have closed the 6557 * write fd. That is taken care of in ClosePostmasterPorts(). 6558 */ 6559 Assert(MyProcPid == PostmasterPid); 6560 if (pipe(postmaster_alive_fds) < 0) 6561 ereport(FATAL, 6562 (errcode_for_file_access(), 6563 errmsg_internal("could not create pipe to monitor postmaster death: %m"))); 6564 6565 /* 6566 * Set O_NONBLOCK to allow testing for the fd's presence with a read() 6567 * call. 6568 */ 6569 if (fcntl(postmaster_alive_fds[POSTMASTER_FD_WATCH], F_SETFL, O_NONBLOCK) == -1) 6570 ereport(FATAL, 6571 (errcode_for_socket_access(), 6572 errmsg_internal("could not set postmaster death monitoring pipe to nonblocking mode: %m"))); 6573 #else 6574 6575 /* 6576 * On Windows, we use a process handle for the same purpose. 6577 */ 6578 if (DuplicateHandle(GetCurrentProcess(), 6579 GetCurrentProcess(), 6580 GetCurrentProcess(), 6581 &PostmasterHandle, 6582 0, 6583 TRUE, 6584 DUPLICATE_SAME_ACCESS) == 0) 6585 ereport(FATAL, 6586 (errmsg_internal("could not duplicate postmaster handle: error code %lu", 6587 GetLastError()))); 6588 #endif /* WIN32 */ 6589 } 6590