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 <signal.h> 11 #include "sendmail.h" 12 13 #ifndef lint 14 #ifdef DAEMON 15 static char sccsid[] = "@(#)daemon.c 6.16 (Berkeley) 03/09/93 (with daemon mode)"; 16 #else 17 static char sccsid[] = "@(#)daemon.c 6.16 (Berkeley) 03/09/93 (without daemon mode)"; 18 #endif 19 #endif /* not lint */ 20 21 #ifdef DAEMON 22 23 # include <netdb.h> 24 # include <sys/wait.h> 25 # include <sys/time.h> 26 27 /* 28 ** DAEMON.C -- routines to use when running as a daemon. 29 ** 30 ** This entire file is highly dependent on the 4.2 BSD 31 ** interprocess communication primitives. No attempt has 32 ** been made to make this file portable to Version 7, 33 ** Version 6, MPX files, etc. If you should try such a 34 ** thing yourself, I recommend chucking the entire file 35 ** and starting from scratch. Basic semantics are: 36 ** 37 ** getrequests() 38 ** Opens a port and initiates a connection. 39 ** Returns in a child. Must set InChannel and 40 ** OutChannel appropriately. 41 ** clrdaemon() 42 ** Close any open files associated with getting 43 ** the connection; this is used when running the queue, 44 ** etc., to avoid having extra file descriptors during 45 ** the queue run and to avoid confusing the network 46 ** code (if it cares). 47 ** makeconnection(host, port, outfile, infile, usesecureport) 48 ** Make a connection to the named host on the given 49 ** port. Set *outfile and *infile to the files 50 ** appropriate for communication. Returns zero on 51 ** success, else an exit status describing the 52 ** error. 53 ** maphostname(map, hbuf, hbufsiz, avp) 54 ** Convert the entry in hbuf into a canonical form. 55 */ 56 /* 57 ** GETREQUESTS -- open mail IPC port and get requests. 58 ** 59 ** Parameters: 60 ** none. 61 ** 62 ** Returns: 63 ** none. 64 ** 65 ** Side Effects: 66 ** Waits until some interesting activity occurs. When 67 ** it does, a child is created to process it, and the 68 ** parent waits for completion. Return from this 69 ** routine is always in the child. The file pointers 70 ** "InChannel" and "OutChannel" should be set to point 71 ** to the communication channel. 72 */ 73 74 int DaemonSocket = -1; /* fd describing socket */ 75 76 getrequests() 77 { 78 int t; 79 register struct servent *sp; 80 int on = 1; 81 bool refusingconnections = TRUE; 82 FILE *pidf; 83 struct sockaddr_in srvraddr; 84 extern void reapchild(); 85 86 /* 87 ** Set up the address for the mailer. 88 */ 89 90 sp = getservbyname("smtp", "tcp"); 91 if (sp == NULL) 92 { 93 syserr("554 server \"smtp\" unknown"); 94 goto severe; 95 } 96 srvraddr.sin_family = AF_INET; 97 srvraddr.sin_addr.s_addr = INADDR_ANY; 98 srvraddr.sin_port = sp->s_port; 99 100 /* 101 ** Try to actually open the connection. 102 */ 103 104 if (tTd(15, 1)) 105 printf("getrequests: port 0x%x\n", srvraddr.sin_port); 106 107 /* get a socket for the SMTP connection */ 108 DaemonSocket = socket(AF_INET, SOCK_STREAM, 0); 109 if (DaemonSocket < 0) 110 { 111 /* probably another daemon already */ 112 syserr("getrequests: can't create socket"); 113 severe: 114 # ifdef LOG 115 if (LogLevel > 0) 116 syslog(LOG_ALERT, "problem creating SMTP socket"); 117 # endif /* LOG */ 118 finis(); 119 } 120 121 /* turn on network debugging? */ 122 if (tTd(15, 101)) 123 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_DEBUG, (char *)&on, sizeof on); 124 125 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof on); 126 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, sizeof on); 127 128 if (bind(DaemonSocket, (struct sockaddr *)&srvraddr, sizeof srvraddr) < 0) 129 { 130 syserr("getrequests: cannot bind"); 131 (void) close(DaemonSocket); 132 goto severe; 133 } 134 135 (void) signal(SIGCHLD, reapchild); 136 137 /* write the pid to the log file for posterity */ 138 pidf = fopen(PidFile, "w"); 139 if (pidf != NULL) 140 { 141 fprintf(pidf, "%d\n", getpid()); 142 fclose(pidf); 143 } 144 145 146 if (tTd(15, 1)) 147 printf("getrequests: %d\n", DaemonSocket); 148 149 for (;;) 150 { 151 register int pid; 152 auto int lotherend; 153 extern bool refuseconnections(); 154 155 /* see if we are rejecting connections */ 156 CurrentLA = getla(); 157 if (refuseconnections()) 158 { 159 if (!refusingconnections) 160 { 161 /* don't queue so peer will fail quickly */ 162 (void) listen(DaemonSocket, 0); 163 refusingconnections = TRUE; 164 } 165 setproctitle("rejecting connections: load average: %d", 166 CurrentLA); 167 sleep(5); 168 continue; 169 } 170 171 if (refusingconnections) 172 { 173 /* start listening again */ 174 if (listen(DaemonSocket, 10) < 0) 175 { 176 syserr("getrequests: cannot listen"); 177 (void) close(DaemonSocket); 178 goto severe; 179 } 180 setproctitle("accepting connections"); 181 refusingconnections = FALSE; 182 } 183 184 /* wait for a connection */ 185 do 186 { 187 errno = 0; 188 lotherend = sizeof RealHostAddr; 189 t = accept(DaemonSocket, 190 (struct sockaddr *)&RealHostAddr, &lotherend); 191 } while (t < 0 && errno == EINTR); 192 if (t < 0) 193 { 194 syserr("getrequests: accept"); 195 sleep(5); 196 continue; 197 } 198 199 /* 200 ** Create a subprocess to process the mail. 201 */ 202 203 if (tTd(15, 2)) 204 printf("getrequests: forking (fd = %d)\n", t); 205 206 pid = fork(); 207 if (pid < 0) 208 { 209 syserr("daemon: cannot fork"); 210 sleep(10); 211 (void) close(t); 212 continue; 213 } 214 215 if (pid == 0) 216 { 217 extern struct hostent *gethostbyaddr(); 218 register struct hostent *hp; 219 char buf[MAXNAME]; 220 extern char *inet_ntoa(); 221 222 /* 223 ** CHILD -- return to caller. 224 ** Collect verified idea of sending host. 225 ** Verify calling user id if possible here. 226 */ 227 228 (void) signal(SIGCHLD, SIG_DFL); 229 230 /* determine host name */ 231 hp = gethostbyaddr((char *) &RealHostAddr.sin_addr, sizeof RealHostAddr.sin_addr, AF_INET); 232 if (hp != NULL) 233 (void) strcpy(buf, hp->h_name); 234 else 235 { 236 /* produce a dotted quad */ 237 (void) sprintf(buf, "[%s]", 238 inet_ntoa(RealHostAddr.sin_addr)); 239 } 240 241 #ifdef LOG 242 if (LogLevel > 10) 243 { 244 /* log connection information */ 245 syslog(LOG_INFO, "connect from %s (%s)", 246 buf, inet_ntoa(RealHostAddr.sin_addr)); 247 } 248 #endif 249 250 /* should we check for illegal connection here? XXX */ 251 252 RealHostName = newstr(buf); 253 254 (void) close(DaemonSocket); 255 InChannel = fdopen(t, "r"); 256 OutChannel = fdopen(dup(t), "w"); 257 if (tTd(15, 2)) 258 printf("getreq: returning\n"); 259 # ifdef LOG 260 if (LogLevel > 11) 261 syslog(LOG_DEBUG, "connected, pid=%d", getpid()); 262 # endif /* LOG */ 263 return; 264 } 265 266 /* close the port so that others will hang (for a while) */ 267 (void) close(t); 268 } 269 /*NOTREACHED*/ 270 } 271 /* 272 ** CLRDAEMON -- reset the daemon connection 273 ** 274 ** Parameters: 275 ** none. 276 ** 277 ** Returns: 278 ** none. 279 ** 280 ** Side Effects: 281 ** releases any resources used by the passive daemon. 282 */ 283 284 clrdaemon() 285 { 286 if (DaemonSocket >= 0) 287 (void) close(DaemonSocket); 288 DaemonSocket = -1; 289 } 290 /* 291 ** MAKECONNECTION -- make a connection to an SMTP socket on another machine. 292 ** 293 ** Parameters: 294 ** host -- the name of the host. 295 ** port -- the port number to connect to. 296 ** mci -- a pointer to the mail connection information 297 ** structure to be filled in. 298 ** usesecureport -- if set, use a low numbered (reserved) 299 ** port to provide some rudimentary authentication. 300 ** 301 ** Returns: 302 ** An exit code telling whether the connection could be 303 ** made and if not why not. 304 ** 305 ** Side Effects: 306 ** none. 307 */ 308 309 struct sockaddr_in CurHostAddr; /* address of current host */ 310 311 int 312 makeconnection(host, port, mci, usesecureport) 313 char *host; 314 u_short port; 315 register MCI *mci; 316 bool usesecureport; 317 { 318 register int i, s; 319 register struct hostent *hp = (struct hostent *)NULL; 320 struct sockaddr_in addr; 321 int sav_errno; 322 extern char *inet_ntoa(); 323 #ifdef NAMED_BIND 324 extern int h_errno; 325 #endif 326 327 /* 328 ** Set up the address for the mailer. 329 ** Accept "[a.b.c.d]" syntax for host name. 330 */ 331 332 #ifdef NAMED_BIND 333 h_errno = 0; 334 #endif 335 errno = 0; 336 337 if (host[0] == '[') 338 { 339 long hid; 340 register char *p = strchr(host, ']'); 341 342 if (p != NULL) 343 { 344 *p = '\0'; 345 hid = inet_addr(&host[1]); 346 if (hid == -1) 347 { 348 /* try it as a host name (avoid MX lookup) */ 349 hp = gethostbyname(&host[1]); 350 *p = ']'; 351 goto gothostent; 352 } 353 *p = ']'; 354 } 355 if (p == NULL) 356 { 357 usrerr("553 Invalid numeric domain spec \"%s\"", host); 358 return (EX_NOHOST); 359 } 360 addr.sin_addr.s_addr = hid; 361 } 362 else 363 { 364 hp = gethostbyname(host); 365 gothostent: 366 if (hp == NULL) 367 { 368 #ifdef NAMED_BIND 369 if (errno == ETIMEDOUT || h_errno == TRY_AGAIN) 370 return (EX_TEMPFAIL); 371 372 /* if name server is specified, assume temp fail */ 373 if (errno == ECONNREFUSED && UseNameServer) 374 return (EX_TEMPFAIL); 375 #endif 376 return (EX_NOHOST); 377 } 378 bcopy(hp->h_addr, (char *) &addr.sin_addr, hp->h_length); 379 i = 1; 380 } 381 382 /* 383 ** Determine the port number. 384 */ 385 386 if (port != 0) 387 addr.sin_port = htons(port); 388 else 389 { 390 register struct servent *sp = getservbyname("smtp", "tcp"); 391 392 if (sp == NULL) 393 { 394 syserr("554 makeconnection: server \"smtp\" unknown"); 395 return (EX_OSERR); 396 } 397 addr.sin_port = sp->s_port; 398 } 399 400 /* 401 ** Try to actually open the connection. 402 */ 403 404 for (;;) 405 { 406 if (tTd(16, 1)) 407 printf("makeconnection (%s [%s])\n", host, 408 inet_ntoa(addr.sin_addr)); 409 410 /* save for logging */ 411 CurHostAddr = addr; 412 413 if (usesecureport) 414 { 415 int rport = IPPORT_RESERVED - 1; 416 417 s = rresvport(&rport); 418 } 419 else 420 { 421 s = socket(AF_INET, SOCK_STREAM, 0); 422 } 423 if (s < 0) 424 { 425 sav_errno = errno; 426 syserr("makeconnection: no socket"); 427 goto failure; 428 } 429 430 if (tTd(16, 1)) 431 printf("makeconnection: fd=%d\n", s); 432 433 /* turn on network debugging? */ 434 if (tTd(16, 101)) 435 { 436 int on = 1; 437 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_DEBUG, 438 (char *)&on, sizeof on); 439 } 440 if (CurEnv->e_xfp != NULL) 441 (void) fflush(CurEnv->e_xfp); /* for debugging */ 442 errno = 0; /* for debugging */ 443 addr.sin_family = AF_INET; 444 if (connect(s, (struct sockaddr *) &addr, sizeof addr) >= 0) 445 break; 446 447 /* couldn't connect.... figure out why */ 448 sav_errno = errno; 449 (void) close(s); 450 if (hp && hp->h_addr_list[i]) 451 { 452 if (tTd(16, 1)) 453 printf("Connect failed; trying new address....\n"); 454 bcopy(hp->h_addr_list[i++], (char *) &addr.sin_addr, 455 hp->h_length); 456 continue; 457 } 458 459 /* failure, decide if temporary or not */ 460 failure: 461 if (transienterror(sav_errno)) 462 return EX_TEMPFAIL; 463 else if (sav_errno == EPERM) 464 { 465 /* why is this happening? */ 466 syserr("makeconnection: funny failure, addr=%lx, port=%x", 467 addr.sin_addr.s_addr, addr.sin_port); 468 return (EX_TEMPFAIL); 469 } 470 else 471 { 472 extern char *errstring(); 473 474 message("%s", errstring(sav_errno)); 475 return (EX_UNAVAILABLE); 476 } 477 } 478 479 /* connection ok, put it into canonical form */ 480 mci->mci_out = fdopen(s, "w"); 481 mci->mci_in = fdopen(dup(s), "r"); 482 483 return (EX_OK); 484 } 485 /* 486 ** MYHOSTNAME -- return the name of this host. 487 ** 488 ** Parameters: 489 ** hostbuf -- a place to return the name of this host. 490 ** size -- the size of hostbuf. 491 ** 492 ** Returns: 493 ** A list of aliases for this host. 494 ** 495 ** Side Effects: 496 ** Sets the MyIpAddrs buffer to a list of my IP addresses. 497 */ 498 499 struct in_addr MyIpAddrs[MAXIPADDR + 1]; 500 501 char ** 502 myhostname(hostbuf, size) 503 char hostbuf[]; 504 int size; 505 { 506 register struct hostent *hp; 507 extern struct hostent *gethostbyname(); 508 509 if (gethostname(hostbuf, size) < 0) 510 { 511 (void) strcpy(hostbuf, "localhost"); 512 } 513 hp = gethostbyname(hostbuf); 514 if (hp != NULL) 515 { 516 (void) strncpy(hostbuf, hp->h_name, size - 1); 517 hostbuf[size - 1] = '\0'; 518 519 if (hp->h_addrtype == AF_INET && hp->h_length == 4) 520 { 521 register int i; 522 523 for (i = 0; i < MAXIPADDR; i++) 524 { 525 if (hp->h_addr_list[i] == NULL) 526 break; 527 MyIpAddrs[i].s_addr = *(u_long *) hp->h_addr_list[i]; 528 } 529 MyIpAddrs[i].s_addr = 0; 530 } 531 532 return (hp->h_aliases); 533 } 534 else 535 return (NULL); 536 } 537 /* 538 ** GETREALHOSTNAME -- get the real host name asociated with a file descriptor 539 ** 540 ** Parameters: 541 ** fd -- the descriptor 542 ** 543 ** Returns: 544 ** The host name associated with this descriptor, if it can 545 ** be determined. 546 ** NULL otherwise. 547 ** 548 ** Side Effects: 549 ** none 550 */ 551 552 char * 553 getrealhostname(fd) 554 int fd; 555 { 556 register struct hostent *hp; 557 struct sockaddr_in sin; 558 int sinlen; 559 char hbuf[MAXNAME]; 560 extern struct hostent *gethostbyaddr(); 561 extern char *inet_ntoa(); 562 563 if (getsockname(fd, (struct sockaddr *) &sin, &sinlen) < 0 || 564 sinlen <= 0) 565 return NULL; 566 hp = gethostbyaddr((char *) &sin.sin_addr, sizeof sin.sin_addr, 567 sin.sin_family); 568 if (hp != NULL) 569 (void) strcpy(hbuf, hp->h_name); 570 else 571 (void) sprintf(hbuf, "[%s]", inet_ntoa(sin.sin_addr)); 572 return hbuf; 573 } 574 /* 575 ** MAPHOSTNAME -- turn a hostname into canonical form 576 ** 577 ** Parameters: 578 ** map -- a pointer to this map (unused). 579 ** hbuf -- a buffer containing a hostname. 580 ** hbsize -- the size of hbuf. 581 ** avp -- unused -- for compatibility with other mapping 582 ** functions. 583 ** 584 ** Returns: 585 ** The mapping, if found. 586 ** NULL if no mapping found. 587 ** 588 ** Side Effects: 589 ** Looks up the host specified in hbuf. If it is not 590 ** the canonical name for that host, return the canonical 591 ** name. 592 */ 593 594 char * 595 maphostname(map, hbuf, hbsize, avp) 596 MAP *map; 597 char *hbuf; 598 int hbsize; 599 char **avp; 600 { 601 register struct hostent *hp; 602 u_long in_addr; 603 char *cp; 604 int i; 605 struct hostent *gethostbyaddr(); 606 607 /* allow room for null */ 608 hbsize--; 609 610 /* 611 * If first character is a bracket, then it is an address 612 * lookup. Address is copied into a temporary buffer to 613 * strip the brackets and to preserve hbuf if address is 614 * unknown. 615 */ 616 617 if (*hbuf != '[') 618 { 619 extern bool getcanonname(); 620 621 if (getcanonname(hbuf, hbsize)) 622 return hbuf; 623 else 624 return NULL; 625 } 626 if ((cp = strchr(hbuf, ']')) == NULL) 627 return (NULL); 628 *cp = '\0'; 629 in_addr = inet_addr(&hbuf[1]); 630 631 /* check to see if this is one of our addresses */ 632 for (i = 0; MyIpAddrs[i].s_addr != 0; i++) 633 { 634 if (MyIpAddrs[i].s_addr == in_addr) 635 { 636 strncpy(hbuf, MyHostName, hbsize); 637 hbuf[hbsize] = '\0'; 638 return hbuf; 639 } 640 } 641 642 /* nope -- ask the name server */ 643 hp = gethostbyaddr((char *)&in_addr, sizeof(struct in_addr), AF_INET); 644 if (hp == NULL) 645 return (NULL); 646 647 /* found a match -- copy out */ 648 if (strlen(hp->h_name) > hbsize) 649 hp->h_name[hbsize] = '\0'; 650 (void) strcpy(hbuf, hp->h_name); 651 return hbuf; 652 } 653 654 # else /* DAEMON */ 655 /* code for systems without sophisticated networking */ 656 657 /* 658 ** MYHOSTNAME -- stub version for case of no daemon code. 659 ** 660 ** Can't convert to upper case here because might be a UUCP name. 661 ** 662 ** Mark, you can change this to be anything you want...... 663 */ 664 665 char ** 666 myhostname(hostbuf, size) 667 char hostbuf[]; 668 int size; 669 { 670 register FILE *f; 671 672 hostbuf[0] = '\0'; 673 f = fopen("/usr/include/whoami", "r"); 674 if (f != NULL) 675 { 676 (void) fgets(hostbuf, size, f); 677 fixcrlf(hostbuf, TRUE); 678 (void) fclose(f); 679 } 680 return (NULL); 681 } 682 /* 683 ** GETREALHOSTNAME -- get the real host name asociated with a file descriptor 684 ** 685 ** Parameters: 686 ** fd -- the descriptor 687 ** 688 ** Returns: 689 ** The host name associated with this descriptor, if it can 690 ** be determined. 691 ** NULL otherwise. 692 ** 693 ** Side Effects: 694 ** none 695 */ 696 697 char * 698 getrealhostname(fd) 699 int fd; 700 { 701 return NULL; 702 } 703 /* 704 ** MAPHOSTNAME -- turn a hostname into canonical form 705 ** 706 ** Parameters: 707 ** map -- a pointer to the database map. 708 ** hbuf -- a buffer containing a hostname. 709 ** avp -- a pointer to a (cf file defined) argument vector. 710 ** 711 ** Returns: 712 ** mapped host name 713 ** FALSE otherwise. 714 ** 715 ** Side Effects: 716 ** Looks up the host specified in hbuf. If it is not 717 ** the canonical name for that host, replace it with 718 ** the canonical name. If the name is unknown, or it 719 ** is already the canonical name, leave it unchanged. 720 */ 721 722 /*ARGSUSED*/ 723 char * 724 maphostname(map, hbuf, hbsize, avp) 725 MAP *map; 726 char *hbuf; 727 int hbsize; 728 char **avp; 729 { 730 return NULL; 731 } 732 733 #endif /* DAEMON */ 734