1 /* 2 * Copyright (c) 1983 Eric P. Allman 3 * Copyright (c) 1988 Regents of the University of California. 4 * All rights reserved. 5 * 6 * %sccs.include.redist.c% 7 */ 8 9 #include <errno.h> 10 #include "sendmail.h" 11 12 #ifndef lint 13 #ifdef DAEMON 14 static char sccsid[] = "@(#)daemon.c 5.45 (Berkeley) 05/31/92 (with daemon mode)"; 15 #else 16 static char sccsid[] = "@(#)daemon.c 5.45 (Berkeley) 05/31/92 (without daemon mode)"; 17 #endif 18 #endif /* not lint */ 19 20 #ifdef DAEMON 21 22 # include <netdb.h> 23 # include <sys/signal.h> 24 # include <sys/wait.h> 25 # include <sys/time.h> 26 # include <sys/resource.h> 27 28 /* 29 ** DAEMON.C -- routines to use when running as a daemon. 30 ** 31 ** This entire file is highly dependent on the 4.2 BSD 32 ** interprocess communication primitives. No attempt has 33 ** been made to make this file portable to Version 7, 34 ** Version 6, MPX files, etc. If you should try such a 35 ** thing yourself, I recommend chucking the entire file 36 ** and starting from scratch. Basic semantics are: 37 ** 38 ** getrequests() 39 ** Opens a port and initiates a connection. 40 ** Returns in a child. Must set InChannel and 41 ** OutChannel appropriately. 42 ** clrdaemon() 43 ** Close any open files associated with getting 44 ** the connection; this is used when running the queue, 45 ** etc., to avoid having extra file descriptors during 46 ** the queue run and to avoid confusing the network 47 ** code (if it cares). 48 ** makeconnection(host, port, outfile, infile, usesecureport) 49 ** Make a connection to the named host on the given 50 ** port. Set *outfile and *infile to the files 51 ** appropriate for communication. Returns zero on 52 ** success, else an exit status describing the 53 ** error. 54 ** maphostname(hbuf, hbufsize) 55 ** Convert the entry in hbuf into a canonical form. It 56 ** may not be larger than hbufsize. 57 */ 58 /* 59 ** GETREQUESTS -- open mail IPC port and get requests. 60 ** 61 ** Parameters: 62 ** none. 63 ** 64 ** Returns: 65 ** none. 66 ** 67 ** Side Effects: 68 ** Waits until some interesting activity occurs. When 69 ** it does, a child is created to process it, and the 70 ** parent waits for completion. Return from this 71 ** routine is always in the child. The file pointers 72 ** "InChannel" and "OutChannel" should be set to point 73 ** to the communication channel. 74 */ 75 76 int DaemonSocket = -1; /* fd describing socket */ 77 78 getrequests() 79 { 80 int t; 81 register struct servent *sp; 82 int on = 1; 83 bool refusingconnections = TRUE; 84 struct sockaddr_in srvraddr; 85 extern void reapchild(); 86 87 /* 88 ** Set up the address for the mailer. 89 */ 90 91 sp = getservbyname("smtp", "tcp"); 92 if (sp == NULL) 93 { 94 syserr("server \"smtp\" unknown"); 95 goto severe; 96 } 97 srvraddr.sin_family = AF_INET; 98 srvraddr.sin_addr.s_addr = INADDR_ANY; 99 srvraddr.sin_port = sp->s_port; 100 101 /* 102 ** Try to actually open the connection. 103 */ 104 105 if (tTd(15, 1)) 106 printf("getrequests: port 0x%x\n", srvraddr.sin_port); 107 108 /* get a socket for the SMTP connection */ 109 DaemonSocket = socket(AF_INET, SOCK_STREAM, 0); 110 if (DaemonSocket < 0) 111 { 112 /* probably another daemon already */ 113 syserr("getrequests: can't create socket"); 114 severe: 115 # ifdef LOG 116 if (LogLevel > 0) 117 syslog(LOG_ALERT, "cannot get connection"); 118 # endif LOG 119 finis(); 120 } 121 122 /* turn on network debugging? */ 123 if (tTd(15, 15)) 124 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_DEBUG, (char *)&on, sizeof on); 125 126 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof on); 127 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, sizeof on); 128 129 if (bind(DaemonSocket, (struct sockaddr *)&srvraddr, sizeof srvraddr) < 0) 130 { 131 syserr("getrequests: cannot bind"); 132 (void) close(DaemonSocket); 133 goto severe; 134 } 135 136 (void) signal(SIGCHLD, reapchild); 137 138 if (tTd(15, 1)) 139 printf("getrequests: %d\n", DaemonSocket); 140 141 for (;;) 142 { 143 register int pid; 144 auto int lotherend; 145 extern bool refuseconnections(); 146 147 /* see if we are rejecting connections */ 148 CurrentLA = getla(); 149 if (refuseconnections()) 150 { 151 if (!refusingconnections) 152 { 153 /* don't queue so peer will fail quickly */ 154 (void) listen(DaemonSocket, 0); 155 refusingconnections = TRUE; 156 } 157 setproctitle("rejecting connections: load average: %.2f", 158 (double)CurrentLA); 159 sleep(5); 160 continue; 161 } 162 163 if (refusingconnections) 164 { 165 /* start listening again */ 166 if (listen(DaemonSocket, 10) < 0) 167 { 168 syserr("getrequests: cannot listen"); 169 (void) close(DaemonSocket); 170 goto severe; 171 } 172 setproctitle("accepting connections"); 173 refusingconnections = FALSE; 174 } 175 176 /* wait for a connection */ 177 do 178 { 179 errno = 0; 180 lotherend = sizeof RealHostAddr; 181 t = accept(DaemonSocket, 182 (struct sockaddr *)&RealHostAddr, &lotherend); 183 } while (t < 0 && errno == EINTR); 184 if (t < 0) 185 { 186 syserr("getrequests: accept"); 187 sleep(5); 188 continue; 189 } 190 191 /* 192 ** Create a subprocess to process the mail. 193 */ 194 195 if (tTd(15, 2)) 196 printf("getrequests: forking (fd = %d)\n", t); 197 198 pid = fork(); 199 if (pid < 0) 200 { 201 syserr("daemon: cannot fork"); 202 sleep(10); 203 (void) close(t); 204 continue; 205 } 206 207 if (pid == 0) 208 { 209 extern struct hostent *gethostbyaddr(); 210 register struct hostent *hp; 211 char buf[MAXNAME]; 212 213 /* 214 ** CHILD -- return to caller. 215 ** Collect verified idea of sending host. 216 ** Verify calling user id if possible here. 217 */ 218 219 (void) signal(SIGCHLD, SIG_DFL); 220 221 /* determine host name */ 222 hp = gethostbyaddr((char *) &RealHostAddr.sin_addr, sizeof RealHostAddr.sin_addr, AF_INET); 223 if (hp != NULL) 224 (void) strcpy(buf, hp->h_name); 225 else 226 { 227 extern char *inet_ntoa(); 228 229 /* produce a dotted quad */ 230 (void) sprintf(buf, "[%s]", 231 inet_ntoa(RealHostAddr.sin_addr)); 232 } 233 234 /* should we check for illegal connection here? XXX */ 235 236 RealHostName = newstr(buf); 237 238 (void) close(DaemonSocket); 239 InChannel = fdopen(t, "r"); 240 OutChannel = fdopen(dup(t), "w"); 241 if (tTd(15, 2)) 242 printf("getreq: returning\n"); 243 # ifdef LOG 244 if (LogLevel > 11) 245 syslog(LOG_DEBUG, "connected, pid=%d", getpid()); 246 # endif LOG 247 return; 248 } 249 250 /* close the port so that others will hang (for a while) */ 251 (void) close(t); 252 } 253 /*NOTREACHED*/ 254 } 255 /* 256 ** CLRDAEMON -- reset the daemon connection 257 ** 258 ** Parameters: 259 ** none. 260 ** 261 ** Returns: 262 ** none. 263 ** 264 ** Side Effects: 265 ** releases any resources used by the passive daemon. 266 */ 267 268 clrdaemon() 269 { 270 if (DaemonSocket >= 0) 271 (void) close(DaemonSocket); 272 DaemonSocket = -1; 273 } 274 /* 275 ** MAKECONNECTION -- make a connection to an SMTP socket on another machine. 276 ** 277 ** Parameters: 278 ** host -- the name of the host. 279 ** port -- the port number to connect to. 280 ** mci -- a pointer to the mail connection information 281 ** structure to be filled in. 282 ** usesecureport -- if set, use a low numbered (reserved) 283 ** port to provide some rudimentary authentication. 284 ** 285 ** Returns: 286 ** An exit code telling whether the connection could be 287 ** made and if not why not. 288 ** 289 ** Side Effects: 290 ** none. 291 */ 292 293 makeconnection(host, port, mci, usesecureport) 294 char *host; 295 u_short port; 296 register MCONINFO *mci; 297 bool usesecureport; 298 { 299 register int i, s; 300 register struct hostent *hp = (struct hostent *)NULL; 301 struct sockaddr_in addr; 302 int sav_errno; 303 extern char *inet_ntoa(); 304 #ifdef NAMED_BIND 305 extern int h_errno; 306 #endif 307 308 /* 309 ** Set up the address for the mailer. 310 ** Accept "[a.b.c.d]" syntax for host name. 311 */ 312 313 #ifdef NAMED_BIND 314 h_errno = 0; 315 #endif 316 errno = 0; 317 318 if (host[0] == '[') 319 { 320 long hid; 321 register char *p = index(host, ']'); 322 323 if (p != NULL) 324 { 325 *p = '\0'; 326 hid = inet_addr(&host[1]); 327 *p = ']'; 328 } 329 if (p == NULL || hid == -1) 330 { 331 usrerr("Invalid numeric domain spec \"%s\"", host); 332 return (EX_NOHOST); 333 } 334 addr.sin_addr.s_addr = hid; 335 } 336 else 337 { 338 hp = gethostbyname(host); 339 if (hp == NULL) 340 { 341 #ifdef NAMED_BIND 342 if (errno == ETIMEDOUT || h_errno == TRY_AGAIN) 343 return (EX_TEMPFAIL); 344 345 /* if name server is specified, assume temp fail */ 346 if (errno == ECONNREFUSED && UseNameServer) 347 return (EX_TEMPFAIL); 348 #endif 349 350 /* 351 ** XXX Should look for mail forwarder record here 352 ** XXX if (h_errno == NO_ADDRESS). 353 */ 354 355 return (EX_NOHOST); 356 } 357 bcopy(hp->h_addr, (char *) &addr.sin_addr, hp->h_length); 358 i = 1; 359 } 360 361 /* 362 ** Determine the port number. 363 */ 364 365 if (port != 0) 366 addr.sin_port = htons(port); 367 else 368 { 369 register struct servent *sp = getservbyname("smtp", "tcp"); 370 371 if (sp == NULL) 372 { 373 syserr("makeconnection: server \"smtp\" unknown"); 374 return (EX_OSFILE); 375 } 376 addr.sin_port = sp->s_port; 377 } 378 379 /* 380 ** Try to actually open the connection. 381 */ 382 383 again: 384 if (tTd(16, 1)) 385 printf("makeconnection (%s [%s])\n", host, 386 inet_ntoa(addr.sin_addr)); 387 388 if (usesecureport) 389 { 390 int rport = IPPORT_RESERVED - 1; 391 392 s = rresvport(&rport); 393 } 394 else 395 { 396 s = socket(AF_INET, SOCK_STREAM, 0); 397 } 398 if (s < 0) 399 { 400 sav_errno = errno; 401 syserr("makeconnection: no socket"); 402 goto failure; 403 } 404 405 if (tTd(16, 1)) 406 printf("makeconnection: %d\n", s); 407 408 /* turn on network debugging? */ 409 if (tTd(16, 14)) 410 { 411 int on = 1; 412 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_DEBUG, (char *)&on, sizeof on); 413 } 414 if (CurEnv->e_xfp != NULL) 415 (void) fflush(CurEnv->e_xfp); /* for debugging */ 416 errno = 0; /* for debugging */ 417 addr.sin_family = AF_INET; 418 if (connect(s, (struct sockaddr *) &addr, sizeof addr) < 0) 419 { 420 sav_errno = errno; 421 (void) close(s); 422 if (hp && hp->h_addr_list[i]) 423 { 424 bcopy(hp->h_addr_list[i++], (char *) &addr.sin_addr, 425 hp->h_length); 426 goto again; 427 } 428 429 /* failure, decide if temporary or not */ 430 failure: 431 switch (sav_errno) 432 { 433 case EISCONN: 434 case ETIMEDOUT: 435 case EINPROGRESS: 436 case EALREADY: 437 case EADDRINUSE: 438 case EHOSTDOWN: 439 case ENETDOWN: 440 case ENETRESET: 441 case ENOBUFS: 442 case ECONNREFUSED: 443 case ECONNRESET: 444 case EHOSTUNREACH: 445 case ENETUNREACH: 446 #ifdef ENOSR 447 case ENOSR: 448 #endif 449 /* there are others, I'm sure..... */ 450 return (EX_TEMPFAIL); 451 452 case EPERM: 453 /* why is this happening? */ 454 syserr("makeconnection: funny failure, addr=%lx, port=%x", 455 addr.sin_addr.s_addr, addr.sin_port); 456 return (EX_TEMPFAIL); 457 458 default: 459 { 460 extern char *errstring(); 461 462 message(Arpa_Info, "%s", errstring(sav_errno)); 463 return (EX_UNAVAILABLE); 464 } 465 } 466 } 467 468 /* connection ok, put it into canonical form */ 469 mci->mci_out = fdopen(s, "w"); 470 mci->mci_in = fdopen(dup(s), "r"); 471 472 return (EX_OK); 473 } 474 /* 475 ** MYHOSTNAME -- return the name of this host. 476 ** 477 ** Parameters: 478 ** hostbuf -- a place to return the name of this host. 479 ** size -- the size of hostbuf. 480 ** 481 ** Returns: 482 ** A list of aliases for this host. 483 ** 484 ** Side Effects: 485 ** none. 486 */ 487 488 char ** 489 myhostname(hostbuf, size) 490 char hostbuf[]; 491 int size; 492 { 493 extern struct hostent *gethostbyname(); 494 struct hostent *hp; 495 496 if (gethostname(hostbuf, size) < 0) 497 { 498 (void) strcpy(hostbuf, "localhost"); 499 } 500 hp = gethostbyname(hostbuf); 501 if (hp != NULL) 502 { 503 (void) strcpy(hostbuf, hp->h_name); 504 return (hp->h_aliases); 505 } 506 else 507 return (NULL); 508 } 509 /* 510 ** MAPHOSTNAME -- turn a hostname into canonical form 511 ** 512 ** Parameters: 513 ** hbuf -- a buffer containing a hostname. 514 ** hbsize -- the size of hbuf. 515 ** 516 ** Returns: 517 ** The mapping, if found. 518 ** NULL if no mapping found. 519 ** 520 ** Side Effects: 521 ** Looks up the host specified in hbuf. If it is not 522 ** the canonical name for that host, return the canonical 523 ** name. 524 */ 525 526 char * 527 maphostname(hbuf, hbsize, avp) 528 char *hbuf; 529 int hbsize; 530 char **avp; 531 { 532 register struct hostent *hp; 533 u_long in_addr; 534 char ptr[256], *cp; 535 struct hostent *gethostbyaddr(); 536 537 /* allow room for trailing dot on correct match */ 538 if (ConfigLevel >= 2) 539 hbsize--; 540 541 /* 542 * If first character is a bracket, then it is an address 543 * lookup. Address is copied into a temporary buffer to 544 * strip the brackets and to preserve hbuf if address is 545 * unknown. 546 */ 547 548 if (*hbuf != '[') 549 { 550 if (getcanonname(hbuf, hbsize)) 551 { 552 /* found a match -- add the trailing dot */ 553 if (ConfigLevel >= 2) 554 (void) strcat(hbuf, "."); 555 return hbuf; 556 } 557 else 558 return NULL; 559 } 560 if ((cp = index(strcpy(ptr, hbuf), ']')) == NULL) 561 return (NULL); 562 *cp = '\0'; 563 in_addr = inet_addr(&ptr[1]); 564 hp = gethostbyaddr((char *)&in_addr, sizeof(struct in_addr), AF_INET); 565 if (hp == NULL) 566 return (NULL); 567 568 /* found a match -- copy and dot terminate */ 569 if (strlen(hp->h_name) >= hbsize) 570 hp->h_name[hbsize - 1] = '\0'; 571 (void) strcpy(hbuf, hp->h_name); 572 if (ConfigLevel >= 2) 573 (void) strcat(hbuf, "."); 574 return hbuf; 575 } 576 577 # else DAEMON 578 /* code for systems without sophisticated networking */ 579 580 /* 581 ** MYHOSTNAME -- stub version for case of no daemon code. 582 ** 583 ** Can't convert to upper case here because might be a UUCP name. 584 ** 585 ** Mark, you can change this to be anything you want...... 586 */ 587 588 char ** 589 myhostname(hostbuf, size) 590 char hostbuf[]; 591 int size; 592 { 593 register FILE *f; 594 595 hostbuf[0] = '\0'; 596 f = fopen("/usr/include/whoami", "r"); 597 if (f != NULL) 598 { 599 (void) fgets(hostbuf, size, f); 600 fixcrlf(hostbuf, TRUE); 601 (void) fclose(f); 602 } 603 return (NULL); 604 } 605 /* 606 ** MAPHOSTNAME -- turn a hostname into canonical form 607 ** 608 ** Parameters: 609 ** hbuf -- a buffer containing a hostname. 610 ** hbsize -- the size of hbuf. 611 ** avp -- a pointer to a (cf file defined) argument vector. 612 ** 613 ** Returns: 614 ** mapped host name 615 ** FALSE otherwise. 616 ** 617 ** Side Effects: 618 ** Looks up the host specified in hbuf. If it is not 619 ** the canonical name for that host, replace it with 620 ** the canonical name. If the name is unknown, or it 621 ** is already the canonical name, leave it unchanged. 622 */ 623 624 /*ARGSUSED*/ 625 char * 626 maphostname(hbuf, hbsize, avp) 627 char *hbuf; 628 int hbsize; 629 char **avp; 630 { 631 return NULL; 632 } 633 634 #endif DAEMON 635