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 6.11 (Berkeley) 02/28/93 (with daemon mode)"; 16 #else 17 static char sccsid[] = "@(#)daemon.c 6.11 (Berkeley) 02/28/93 (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 struct sockaddr_in srvraddr; 83 extern void reapchild(); 84 85 /* 86 ** Set up the address for the mailer. 87 */ 88 89 sp = getservbyname("smtp", "tcp"); 90 if (sp == NULL) 91 { 92 syserr("554 server \"smtp\" unknown"); 93 goto severe; 94 } 95 srvraddr.sin_family = AF_INET; 96 srvraddr.sin_addr.s_addr = INADDR_ANY; 97 srvraddr.sin_port = sp->s_port; 98 99 /* 100 ** Try to actually open the connection. 101 */ 102 103 if (tTd(15, 1)) 104 printf("getrequests: port 0x%x\n", srvraddr.sin_port); 105 106 /* get a socket for the SMTP connection */ 107 DaemonSocket = socket(AF_INET, SOCK_STREAM, 0); 108 if (DaemonSocket < 0) 109 { 110 /* probably another daemon already */ 111 syserr("getrequests: can't create socket"); 112 severe: 113 # ifdef LOG 114 if (LogLevel > 0) 115 syslog(LOG_ALERT, "problem creating SMTP socket"); 116 # endif /* LOG */ 117 finis(); 118 } 119 120 /* turn on network debugging? */ 121 if (tTd(15, 101)) 122 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_DEBUG, (char *)&on, sizeof on); 123 124 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof on); 125 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, sizeof on); 126 127 if (bind(DaemonSocket, (struct sockaddr *)&srvraddr, sizeof srvraddr) < 0) 128 { 129 syserr("getrequests: cannot bind"); 130 (void) close(DaemonSocket); 131 goto severe; 132 } 133 134 (void) signal(SIGCHLD, reapchild); 135 136 if (tTd(15, 1)) 137 printf("getrequests: %d\n", DaemonSocket); 138 139 for (;;) 140 { 141 register int pid; 142 auto int lotherend; 143 extern bool refuseconnections(); 144 145 /* see if we are rejecting connections */ 146 CurrentLA = getla(); 147 if (refuseconnections()) 148 { 149 if (!refusingconnections) 150 { 151 /* don't queue so peer will fail quickly */ 152 (void) listen(DaemonSocket, 0); 153 refusingconnections = TRUE; 154 } 155 setproctitle("rejecting connections: load average: %d", 156 CurrentLA); 157 sleep(5); 158 continue; 159 } 160 161 if (refusingconnections) 162 { 163 /* start listening again */ 164 if (listen(DaemonSocket, 10) < 0) 165 { 166 syserr("getrequests: cannot listen"); 167 (void) close(DaemonSocket); 168 goto severe; 169 } 170 setproctitle("accepting connections"); 171 refusingconnections = FALSE; 172 } 173 174 /* wait for a connection */ 175 do 176 { 177 errno = 0; 178 lotherend = sizeof RealHostAddr; 179 t = accept(DaemonSocket, 180 (struct sockaddr *)&RealHostAddr, &lotherend); 181 } while (t < 0 && errno == EINTR); 182 if (t < 0) 183 { 184 syserr("getrequests: accept"); 185 sleep(5); 186 continue; 187 } 188 189 /* 190 ** Create a subprocess to process the mail. 191 */ 192 193 if (tTd(15, 2)) 194 printf("getrequests: forking (fd = %d)\n", t); 195 196 pid = fork(); 197 if (pid < 0) 198 { 199 syserr("daemon: cannot fork"); 200 sleep(10); 201 (void) close(t); 202 continue; 203 } 204 205 if (pid == 0) 206 { 207 extern struct hostent *gethostbyaddr(); 208 register struct hostent *hp; 209 char buf[MAXNAME]; 210 extern char *inet_ntoa(); 211 212 /* 213 ** CHILD -- return to caller. 214 ** Collect verified idea of sending host. 215 ** Verify calling user id if possible here. 216 */ 217 218 (void) signal(SIGCHLD, SIG_DFL); 219 220 /* determine host name */ 221 hp = gethostbyaddr((char *) &RealHostAddr.sin_addr, sizeof RealHostAddr.sin_addr, AF_INET); 222 if (hp != NULL) 223 (void) strcpy(buf, hp->h_name); 224 else 225 { 226 /* produce a dotted quad */ 227 (void) sprintf(buf, "[%s]", 228 inet_ntoa(RealHostAddr.sin_addr)); 229 } 230 231 #ifdef LOG 232 if (LogLevel > 10) 233 { 234 /* log connection information */ 235 syslog(LOG_INFO, "connect from %s (%s)", 236 buf, inet_ntoa(RealHostAddr.sin_addr)); 237 } 238 #endif 239 240 /* should we check for illegal connection here? XXX */ 241 242 RealHostName = newstr(buf); 243 244 (void) close(DaemonSocket); 245 InChannel = fdopen(t, "r"); 246 OutChannel = fdopen(dup(t), "w"); 247 if (tTd(15, 2)) 248 printf("getreq: returning\n"); 249 # ifdef LOG 250 if (LogLevel > 11) 251 syslog(LOG_DEBUG, "connected, pid=%d", getpid()); 252 # endif /* LOG */ 253 return; 254 } 255 256 /* close the port so that others will hang (for a while) */ 257 (void) close(t); 258 } 259 /*NOTREACHED*/ 260 } 261 /* 262 ** CLRDAEMON -- reset the daemon connection 263 ** 264 ** Parameters: 265 ** none. 266 ** 267 ** Returns: 268 ** none. 269 ** 270 ** Side Effects: 271 ** releases any resources used by the passive daemon. 272 */ 273 274 clrdaemon() 275 { 276 if (DaemonSocket >= 0) 277 (void) close(DaemonSocket); 278 DaemonSocket = -1; 279 } 280 /* 281 ** MAKECONNECTION -- make a connection to an SMTP socket on another machine. 282 ** 283 ** Parameters: 284 ** host -- the name of the host. 285 ** port -- the port number to connect to. 286 ** mci -- a pointer to the mail connection information 287 ** structure to be filled in. 288 ** usesecureport -- if set, use a low numbered (reserved) 289 ** port to provide some rudimentary authentication. 290 ** 291 ** Returns: 292 ** An exit code telling whether the connection could be 293 ** made and if not why not. 294 ** 295 ** Side Effects: 296 ** none. 297 */ 298 299 struct sockaddr_in CurHostAddr; /* address of current host */ 300 301 int 302 makeconnection(host, port, mci, usesecureport) 303 char *host; 304 u_short port; 305 register MCI *mci; 306 bool usesecureport; 307 { 308 register int i, s; 309 register struct hostent *hp = (struct hostent *)NULL; 310 struct sockaddr_in addr; 311 int sav_errno; 312 extern char *inet_ntoa(); 313 #ifdef NAMED_BIND 314 extern int h_errno; 315 #endif 316 317 /* 318 ** Set up the address for the mailer. 319 ** Accept "[a.b.c.d]" syntax for host name. 320 */ 321 322 #ifdef NAMED_BIND 323 h_errno = 0; 324 #endif 325 errno = 0; 326 327 if (host[0] == '[') 328 { 329 long hid; 330 register char *p = strchr(host, ']'); 331 332 if (p != NULL) 333 { 334 *p = '\0'; 335 hid = inet_addr(&host[1]); 336 *p = ']'; 337 } 338 if (p == NULL || hid == -1) 339 { 340 usrerr("553 Invalid numeric domain spec \"%s\"", host); 341 return (EX_NOHOST); 342 } 343 addr.sin_addr.s_addr = hid; 344 } 345 else 346 { 347 hp = gethostbyname(host); 348 if (hp == NULL) 349 { 350 #ifdef NAMED_BIND 351 if (errno == ETIMEDOUT || h_errno == TRY_AGAIN) 352 return (EX_TEMPFAIL); 353 354 /* if name server is specified, assume temp fail */ 355 if (errno == ECONNREFUSED && UseNameServer) 356 return (EX_TEMPFAIL); 357 #endif 358 return (EX_NOHOST); 359 } 360 bcopy(hp->h_addr, (char *) &addr.sin_addr, hp->h_length); 361 i = 1; 362 } 363 364 /* 365 ** Determine the port number. 366 */ 367 368 if (port != 0) 369 addr.sin_port = htons(port); 370 else 371 { 372 register struct servent *sp = getservbyname("smtp", "tcp"); 373 374 if (sp == NULL) 375 { 376 syserr("554 makeconnection: server \"smtp\" unknown"); 377 return (EX_OSERR); 378 } 379 addr.sin_port = sp->s_port; 380 } 381 382 /* 383 ** Try to actually open the connection. 384 */ 385 386 for (;;) 387 { 388 if (tTd(16, 1)) 389 printf("makeconnection (%s [%s])\n", host, 390 inet_ntoa(addr.sin_addr)); 391 392 if (usesecureport) 393 { 394 int rport = IPPORT_RESERVED - 1; 395 396 s = rresvport(&rport); 397 } 398 else 399 { 400 s = socket(AF_INET, SOCK_STREAM, 0); 401 } 402 if (s < 0) 403 { 404 sav_errno = errno; 405 syserr("makeconnection: no socket"); 406 goto failure; 407 } 408 409 if (tTd(16, 1)) 410 printf("makeconnection: fd=%d\n", s); 411 412 /* turn on network debugging? */ 413 if (tTd(16, 101)) 414 { 415 int on = 1; 416 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_DEBUG, 417 (char *)&on, sizeof on); 418 } 419 if (CurEnv->e_xfp != NULL) 420 (void) fflush(CurEnv->e_xfp); /* for debugging */ 421 errno = 0; /* for debugging */ 422 addr.sin_family = AF_INET; 423 if (connect(s, (struct sockaddr *) &addr, sizeof addr) >= 0) 424 break; 425 426 /* couldn't connect.... figure out why */ 427 sav_errno = errno; 428 (void) close(s); 429 if (hp && hp->h_addr_list[i]) 430 { 431 if (tTd(16, 1)) 432 printf("Connect failed; trying new address....\n"); 433 bcopy(hp->h_addr_list[i++], (char *) &addr.sin_addr, 434 hp->h_length); 435 continue; 436 } 437 438 /* failure, decide if temporary or not */ 439 failure: 440 switch (sav_errno) 441 { 442 case EISCONN: 443 case ETIMEDOUT: 444 case EINPROGRESS: 445 case EALREADY: 446 case EADDRINUSE: 447 case EHOSTDOWN: 448 case ENETDOWN: 449 case ENETRESET: 450 case ENOBUFS: 451 case ECONNREFUSED: 452 case ECONNRESET: 453 case EHOSTUNREACH: 454 case ENETUNREACH: 455 #ifdef ENOSR 456 case ENOSR: 457 #endif 458 /* there are others, I'm sure..... */ 459 return (EX_TEMPFAIL); 460 461 case EPERM: 462 /* why is this happening? */ 463 syserr("makeconnection: funny failure, addr=%lx, port=%x", 464 addr.sin_addr.s_addr, addr.sin_port); 465 return (EX_TEMPFAIL); 466 467 default: 468 { 469 extern char *errstring(); 470 471 message("%s", errstring(sav_errno)); 472 return (EX_UNAVAILABLE); 473 } 474 } 475 } 476 477 /* connection ok, put it into canonical form */ 478 mci->mci_out = fdopen(s, "w"); 479 mci->mci_in = fdopen(dup(s), "r"); 480 481 /* save for logging */ 482 CurHostAddr = addr; 483 484 return (EX_OK); 485 } 486 /* 487 ** MYHOSTNAME -- return the name of this host. 488 ** 489 ** Parameters: 490 ** hostbuf -- a place to return the name of this host. 491 ** size -- the size of hostbuf. 492 ** 493 ** Returns: 494 ** A list of aliases for this host. 495 ** 496 ** Side Effects: 497 ** Sets the MyIpAddrs buffer to a list of my IP addresses. 498 */ 499 500 struct in_addr MyIpAddrs[MAXIPADDR + 1]; 501 502 char ** 503 myhostname(hostbuf, size) 504 char hostbuf[]; 505 int size; 506 { 507 register struct hostent *hp; 508 extern struct hostent *gethostbyname(); 509 510 if (gethostname(hostbuf, size) < 0) 511 { 512 (void) strcpy(hostbuf, "localhost"); 513 } 514 hp = gethostbyname(hostbuf); 515 if (hp != NULL) 516 { 517 (void) strncpy(hostbuf, hp->h_name, size - 1); 518 hostbuf[size - 1] = '\0'; 519 520 if (hp->h_addrtype == AF_INET && hp->h_length == 4) 521 { 522 register int i; 523 524 for (i = 0; i < MAXIPADDR; i++) 525 { 526 if (hp->h_addr_list[i] == NULL) 527 break; 528 MyIpAddrs[i].s_addr = *(u_long *) hp->h_addr_list[i]; 529 } 530 MyIpAddrs[i].s_addr = 0; 531 } 532 533 return (hp->h_aliases); 534 } 535 else 536 return (NULL); 537 } 538 /* 539 ** GETREALHOSTNAME -- get the real host name asociated with a file descriptor 540 ** 541 ** Parameters: 542 ** fd -- the descriptor 543 ** 544 ** Returns: 545 ** The host name associated with this descriptor, if it can 546 ** be determined. 547 ** NULL otherwise. 548 ** 549 ** Side Effects: 550 ** none 551 */ 552 553 char * 554 getrealhostname(fd) 555 int fd; 556 { 557 register struct hostent *hp; 558 struct sockaddr_in sin; 559 int sinlen; 560 char hbuf[MAXNAME]; 561 extern struct hostent *gethostbyaddr(); 562 extern char *inet_ntoa(); 563 564 if (getsockname(fd, (struct sockaddr *) &sin, &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