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 5.44 (Berkeley) 05/25/92 (with daemon mode)"; 15 #else 16 static char sccsid[] = "@(#)daemon.c 5.44 (Berkeley) 05/25/92 (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 ** outfile -- a pointer to a place to put the outfile 281 ** descriptor. 282 ** infile -- ditto for infile. 283 ** usesecureport -- if set, use a low numbered (reserved) 284 ** port to provide some rudimentary authentication. 285 ** 286 ** Returns: 287 ** An exit code telling whether the connection could be 288 ** made and if not why not. 289 ** 290 ** Side Effects: 291 ** none. 292 */ 293 294 makeconnection(host, port, outfile, infile, usesecureport) 295 char *host; 296 u_short port; 297 FILE **outfile; 298 FILE **infile; 299 bool usesecureport; 300 { 301 register int i, s; 302 register struct hostent *hp = (struct hostent *)NULL; 303 struct sockaddr_in addr; 304 int sav_errno; 305 extern char *inet_ntoa(); 306 #ifdef NAMED_BIND 307 extern int h_errno; 308 #endif 309 310 /* 311 ** Set up the address for the mailer. 312 ** Accept "[a.b.c.d]" syntax for host name. 313 */ 314 315 #ifdef NAMED_BIND 316 h_errno = 0; 317 #endif 318 errno = 0; 319 320 if (host[0] == '[') 321 { 322 long hid; 323 register char *p = index(host, ']'); 324 325 if (p != NULL) 326 { 327 *p = '\0'; 328 hid = inet_addr(&host[1]); 329 *p = ']'; 330 } 331 if (p == NULL || hid == -1) 332 { 333 usrerr("Invalid numeric domain spec \"%s\"", host); 334 return (EX_NOHOST); 335 } 336 addr.sin_addr.s_addr = hid; 337 } 338 else 339 { 340 hp = gethostbyname(host); 341 if (hp == NULL) 342 { 343 #ifdef NAMED_BIND 344 if (errno == ETIMEDOUT || h_errno == TRY_AGAIN) 345 return (EX_TEMPFAIL); 346 347 /* if name server is specified, assume temp fail */ 348 if (errno == ECONNREFUSED && UseNameServer) 349 return (EX_TEMPFAIL); 350 #endif 351 352 /* 353 ** XXX Should look for mail forwarder record here 354 ** XXX if (h_errno == NO_ADDRESS). 355 */ 356 357 return (EX_NOHOST); 358 } 359 bcopy(hp->h_addr, (char *) &addr.sin_addr, hp->h_length); 360 i = 1; 361 } 362 363 /* 364 ** Determine the port number. 365 */ 366 367 if (port != 0) 368 addr.sin_port = htons(port); 369 else 370 { 371 register struct servent *sp = getservbyname("smtp", "tcp"); 372 373 if (sp == NULL) 374 { 375 syserr("makeconnection: server \"smtp\" unknown"); 376 return (EX_OSFILE); 377 } 378 addr.sin_port = sp->s_port; 379 } 380 381 /* 382 ** Try to actually open the connection. 383 */ 384 385 again: 386 if (tTd(16, 1)) 387 printf("makeconnection (%s [%s])\n", host, 388 inet_ntoa(addr.sin_addr)); 389 390 if (usesecureport) 391 { 392 int rport = IPPORT_RESERVED - 1; 393 394 s = rresvport(&rport); 395 } 396 else 397 { 398 s = socket(AF_INET, SOCK_STREAM, 0); 399 } 400 if (s < 0) 401 { 402 sav_errno = errno; 403 syserr("makeconnection: no socket"); 404 goto failure; 405 } 406 407 if (tTd(16, 1)) 408 printf("makeconnection: %d\n", s); 409 410 /* turn on network debugging? */ 411 if (tTd(16, 14)) 412 { 413 int on = 1; 414 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_DEBUG, (char *)&on, sizeof on); 415 } 416 if (CurEnv->e_xfp != NULL) 417 (void) fflush(CurEnv->e_xfp); /* for debugging */ 418 errno = 0; /* for debugging */ 419 addr.sin_family = AF_INET; 420 if (connect(s, (struct sockaddr *) &addr, sizeof addr) < 0) 421 { 422 sav_errno = errno; 423 (void) close(s); 424 if (hp && hp->h_addr_list[i]) 425 { 426 bcopy(hp->h_addr_list[i++], (char *) &addr.sin_addr, 427 hp->h_length); 428 goto again; 429 } 430 431 /* failure, decide if temporary or not */ 432 failure: 433 switch (sav_errno) 434 { 435 case EISCONN: 436 case ETIMEDOUT: 437 case EINPROGRESS: 438 case EALREADY: 439 case EADDRINUSE: 440 case EHOSTDOWN: 441 case ENETDOWN: 442 case ENETRESET: 443 case ENOBUFS: 444 case ECONNREFUSED: 445 case ECONNRESET: 446 case EHOSTUNREACH: 447 case ENETUNREACH: 448 #ifdef ENOSR 449 case ENOSR: 450 #endif 451 /* there are others, I'm sure..... */ 452 return (EX_TEMPFAIL); 453 454 case EPERM: 455 /* why is this happening? */ 456 syserr("makeconnection: funny failure, addr=%lx, port=%x", 457 addr.sin_addr.s_addr, addr.sin_port); 458 return (EX_TEMPFAIL); 459 460 default: 461 { 462 extern char *errstring(); 463 464 message(Arpa_Info, "%s", errstring(sav_errno)); 465 return (EX_UNAVAILABLE); 466 } 467 } 468 } 469 470 /* connection ok, put it into canonical form */ 471 *outfile = fdopen(s, "w"); 472 *infile = fdopen(dup(s), "r"); 473 474 return (EX_OK); 475 } 476 /* 477 ** MYHOSTNAME -- return the name of this host. 478 ** 479 ** Parameters: 480 ** hostbuf -- a place to return the name of this host. 481 ** size -- the size of hostbuf. 482 ** 483 ** Returns: 484 ** A list of aliases for this host. 485 ** 486 ** Side Effects: 487 ** none. 488 */ 489 490 char ** 491 myhostname(hostbuf, size) 492 char hostbuf[]; 493 int size; 494 { 495 extern struct hostent *gethostbyname(); 496 struct hostent *hp; 497 498 if (gethostname(hostbuf, size) < 0) 499 { 500 (void) strcpy(hostbuf, "localhost"); 501 } 502 hp = gethostbyname(hostbuf); 503 if (hp != NULL) 504 { 505 (void) strcpy(hostbuf, hp->h_name); 506 return (hp->h_aliases); 507 } 508 else 509 return (NULL); 510 } 511 /* 512 ** MAPHOSTNAME -- turn a hostname into canonical form 513 ** 514 ** Parameters: 515 ** hbuf -- a buffer containing a hostname. 516 ** hbsize -- the size of hbuf. 517 ** 518 ** Returns: 519 ** The mapping, if found. 520 ** NULL if no mapping found. 521 ** 522 ** Side Effects: 523 ** Looks up the host specified in hbuf. If it is not 524 ** the canonical name for that host, return the canonical 525 ** name. 526 */ 527 528 char * 529 maphostname(hbuf, hbsize, avp) 530 char *hbuf; 531 int hbsize; 532 char **avp; 533 { 534 register struct hostent *hp; 535 u_long in_addr; 536 char ptr[256], *cp; 537 struct hostent *gethostbyaddr(); 538 539 /* allow room for trailing dot on correct match */ 540 if (ConfigLevel >= 2) 541 hbsize--; 542 543 /* 544 * If first character is a bracket, then it is an address 545 * lookup. Address is copied into a temporary buffer to 546 * strip the brackets and to preserve hbuf if address is 547 * unknown. 548 */ 549 550 if (*hbuf != '[') 551 { 552 if (getcanonname(hbuf, hbsize)) 553 { 554 /* found a match -- add the trailing dot */ 555 if (ConfigLevel >= 2) 556 (void) strcat(hbuf, "."); 557 return hbuf; 558 } 559 else 560 return NULL; 561 } 562 if ((cp = index(strcpy(ptr, hbuf), ']')) == NULL) 563 return (NULL); 564 *cp = '\0'; 565 in_addr = inet_addr(&ptr[1]); 566 hp = gethostbyaddr((char *)&in_addr, sizeof(struct in_addr), AF_INET); 567 if (hp == NULL) 568 return (NULL); 569 570 /* found a match -- copy and dot terminate */ 571 if (strlen(hp->h_name) >= hbsize) 572 hp->h_name[hbsize - 1] = '\0'; 573 (void) strcpy(hbuf, hp->h_name); 574 if (ConfigLevel >= 2) 575 (void) strcat(hbuf, "."); 576 return hbuf; 577 } 578 579 # else DAEMON 580 /* code for systems without sophisticated networking */ 581 582 /* 583 ** MYHOSTNAME -- stub version for case of no daemon code. 584 ** 585 ** Can't convert to upper case here because might be a UUCP name. 586 ** 587 ** Mark, you can change this to be anything you want...... 588 */ 589 590 char ** 591 myhostname(hostbuf, size) 592 char hostbuf[]; 593 int size; 594 { 595 register FILE *f; 596 597 hostbuf[0] = '\0'; 598 f = fopen("/usr/include/whoami", "r"); 599 if (f != NULL) 600 { 601 (void) fgets(hostbuf, size, f); 602 fixcrlf(hostbuf, TRUE); 603 (void) fclose(f); 604 } 605 return (NULL); 606 } 607 /* 608 ** MAPHOSTNAME -- turn a hostname into canonical form 609 ** 610 ** Parameters: 611 ** hbuf -- a buffer containing a hostname. 612 ** hbsize -- the size of hbuf. 613 ** avp -- a pointer to a (cf file defined) argument vector. 614 ** 615 ** Returns: 616 ** mapped host name 617 ** FALSE otherwise. 618 ** 619 ** Side Effects: 620 ** Looks up the host specified in hbuf. If it is not 621 ** the canonical name for that host, replace it with 622 ** the canonical name. If the name is unknown, or it 623 ** is already the canonical name, leave it unchanged. 624 */ 625 626 /*ARGSUSED*/ 627 char * 628 maphostname(hbuf, hbsize, avp) 629 char *hbuf; 630 int hbsize; 631 char **avp; 632 { 633 return NULL; 634 } 635 636 #endif DAEMON 637