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 5.47 (Berkeley) 07/12/92 (with daemon mode)"; 15 #else 16 static char sccsid[] = "@(#)daemon.c 5.47 (Berkeley) 07/12/92 (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, avp) 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 int 294 makeconnection(host, port, mci, usesecureport) 295 char *host; 296 u_short port; 297 register MCI *mci; 298 bool usesecureport; 299 { 300 register int i, s; 301 register struct hostent *hp = (struct hostent *)NULL; 302 struct sockaddr_in addr; 303 int sav_errno; 304 extern char *inet_ntoa(); 305 #ifdef NAMED_BIND 306 extern int h_errno; 307 #endif 308 309 /* 310 ** Set up the address for the mailer. 311 ** Accept "[a.b.c.d]" syntax for host name. 312 */ 313 314 #ifdef NAMED_BIND 315 h_errno = 0; 316 #endif 317 errno = 0; 318 319 if (host[0] == '[') 320 { 321 long hid; 322 register char *p = index(host, ']'); 323 324 if (p != NULL) 325 { 326 *p = '\0'; 327 hid = inet_addr(&host[1]); 328 *p = ']'; 329 } 330 if (p == NULL || hid == -1) 331 { 332 usrerr("Invalid numeric domain spec \"%s\"", host); 333 return (EX_NOHOST); 334 } 335 addr.sin_addr.s_addr = hid; 336 } 337 else 338 { 339 hp = gethostbyname(host); 340 if (hp == NULL) 341 { 342 #ifdef NAMED_BIND 343 if (errno == ETIMEDOUT || h_errno == TRY_AGAIN) 344 return (EX_TEMPFAIL); 345 346 /* if name server is specified, assume temp fail */ 347 if (errno == ECONNREFUSED && UseNameServer) 348 return (EX_TEMPFAIL); 349 #endif 350 351 /* 352 ** XXX Should look for mail forwarder record here 353 ** XXX if (h_errno == NO_ADDRESS). 354 */ 355 356 return (EX_NOHOST); 357 } 358 bcopy(hp->h_addr, (char *) &addr.sin_addr, hp->h_length); 359 i = 1; 360 } 361 362 /* 363 ** Determine the port number. 364 */ 365 366 if (port != 0) 367 addr.sin_port = htons(port); 368 else 369 { 370 register struct servent *sp = getservbyname("smtp", "tcp"); 371 372 if (sp == NULL) 373 { 374 syserr("makeconnection: server \"smtp\" unknown"); 375 return (EX_OSFILE); 376 } 377 addr.sin_port = sp->s_port; 378 } 379 380 /* 381 ** Try to actually open the connection. 382 */ 383 384 again: 385 if (tTd(16, 1)) 386 printf("makeconnection (%s [%s])\n", host, 387 inet_ntoa(addr.sin_addr)); 388 389 if (usesecureport) 390 { 391 int rport = IPPORT_RESERVED - 1; 392 393 s = rresvport(&rport); 394 } 395 else 396 { 397 s = socket(AF_INET, SOCK_STREAM, 0); 398 } 399 if (s < 0) 400 { 401 sav_errno = errno; 402 syserr("makeconnection: no socket"); 403 goto failure; 404 } 405 406 if (tTd(16, 1)) 407 printf("makeconnection: fd=%d\n", s); 408 409 /* turn on network debugging? */ 410 if (tTd(16, 14)) 411 { 412 int on = 1; 413 (void) setsockopt(DaemonSocket, SOL_SOCKET, SO_DEBUG, (char *)&on, sizeof on); 414 } 415 if (CurEnv->e_xfp != NULL) 416 (void) fflush(CurEnv->e_xfp); /* for debugging */ 417 errno = 0; /* for debugging */ 418 addr.sin_family = AF_INET; 419 if (connect(s, (struct sockaddr *) &addr, sizeof addr) < 0) 420 { 421 sav_errno = errno; 422 (void) close(s); 423 if (hp && hp->h_addr_list[i]) 424 { 425 bcopy(hp->h_addr_list[i++], (char *) &addr.sin_addr, 426 hp->h_length); 427 goto again; 428 } 429 430 /* failure, decide if temporary or not */ 431 failure: 432 switch (sav_errno) 433 { 434 case EISCONN: 435 case ETIMEDOUT: 436 case EINPROGRESS: 437 case EALREADY: 438 case EADDRINUSE: 439 case EHOSTDOWN: 440 case ENETDOWN: 441 case ENETRESET: 442 case ENOBUFS: 443 case ECONNREFUSED: 444 case ECONNRESET: 445 case EHOSTUNREACH: 446 case ENETUNREACH: 447 #ifdef ENOSR 448 case ENOSR: 449 #endif 450 /* there are others, I'm sure..... */ 451 return (EX_TEMPFAIL); 452 453 case EPERM: 454 /* why is this happening? */ 455 syserr("makeconnection: funny failure, addr=%lx, port=%x", 456 addr.sin_addr.s_addr, addr.sin_port); 457 return (EX_TEMPFAIL); 458 459 default: 460 { 461 extern char *errstring(); 462 463 message(Arpa_Info, "%s", errstring(sav_errno)); 464 return (EX_UNAVAILABLE); 465 } 466 } 467 } 468 469 /* connection ok, put it into canonical form */ 470 mci->mci_out = fdopen(s, "w"); 471 mci->mci_in = fdopen(dup(s), "r"); 472 473 return (EX_OK); 474 } 475 /* 476 ** MYHOSTNAME -- return the name of this host. 477 ** 478 ** Parameters: 479 ** hostbuf -- a place to return the name of this host. 480 ** size -- the size of hostbuf. 481 ** 482 ** Returns: 483 ** A list of aliases for this host. 484 ** 485 ** Side Effects: 486 ** none. 487 */ 488 489 char ** 490 myhostname(hostbuf, size) 491 char hostbuf[]; 492 int size; 493 { 494 extern struct hostent *gethostbyname(); 495 struct hostent *hp; 496 497 if (gethostname(hostbuf, size) < 0) 498 { 499 (void) strcpy(hostbuf, "localhost"); 500 } 501 hp = gethostbyname(hostbuf); 502 if (hp != NULL) 503 { 504 (void) strcpy(hostbuf, hp->h_name); 505 return (hp->h_aliases); 506 } 507 else 508 return (NULL); 509 } 510 /* 511 ** MAPHOSTNAME -- turn a hostname into canonical form 512 ** 513 ** Parameters: 514 ** hbuf -- a buffer containing a hostname. 515 ** hbsize -- the size of hbuf. 516 ** avp -- unused -- for compatibility with other mapping 517 ** functions. 518 ** 519 ** Returns: 520 ** The mapping, if found. 521 ** NULL if no mapping found. 522 ** 523 ** Side Effects: 524 ** Looks up the host specified in hbuf. If it is not 525 ** the canonical name for that host, return the canonical 526 ** name. 527 */ 528 529 char * 530 maphostname(hbuf, hbsize, avp) 531 char *hbuf; 532 int hbsize; 533 char **avp; 534 { 535 register struct hostent *hp; 536 u_long in_addr; 537 char ptr[256], *cp; 538 struct hostent *gethostbyaddr(); 539 540 /* allow room for trailing dot on correct match */ 541 if (ConfigLevel >= 2) 542 hbsize--; 543 544 /* 545 * If first character is a bracket, then it is an address 546 * lookup. Address is copied into a temporary buffer to 547 * strip the brackets and to preserve hbuf if address is 548 * unknown. 549 */ 550 551 if (*hbuf != '[') 552 { 553 extern bool getcanonname(); 554 555 if (getcanonname(hbuf, hbsize)) 556 { 557 /* found a match -- add the trailing dot */ 558 if (ConfigLevel >= 2) 559 (void) strcat(hbuf, "."); 560 return hbuf; 561 } 562 else 563 return NULL; 564 } 565 if ((cp = index(strcpy(ptr, hbuf), ']')) == NULL) 566 return (NULL); 567 *cp = '\0'; 568 in_addr = inet_addr(&ptr[1]); 569 hp = gethostbyaddr((char *)&in_addr, sizeof(struct in_addr), AF_INET); 570 if (hp == NULL) 571 return (NULL); 572 573 /* found a match -- copy and dot terminate */ 574 if (strlen(hp->h_name) >= hbsize) 575 hp->h_name[hbsize - 1] = '\0'; 576 (void) strcpy(hbuf, hp->h_name); 577 if (ConfigLevel >= 2) 578 (void) strcat(hbuf, "."); 579 return hbuf; 580 } 581 582 # else DAEMON 583 /* code for systems without sophisticated networking */ 584 585 /* 586 ** MYHOSTNAME -- stub version for case of no daemon code. 587 ** 588 ** Can't convert to upper case here because might be a UUCP name. 589 ** 590 ** Mark, you can change this to be anything you want...... 591 */ 592 593 char ** 594 myhostname(hostbuf, size) 595 char hostbuf[]; 596 int size; 597 { 598 register FILE *f; 599 600 hostbuf[0] = '\0'; 601 f = fopen("/usr/include/whoami", "r"); 602 if (f != NULL) 603 { 604 (void) fgets(hostbuf, size, f); 605 fixcrlf(hostbuf, TRUE); 606 (void) fclose(f); 607 } 608 return (NULL); 609 } 610 /* 611 ** MAPHOSTNAME -- turn a hostname into canonical form 612 ** 613 ** Parameters: 614 ** hbuf -- a buffer containing a hostname. 615 ** hbsize -- the size of hbuf. 616 ** avp -- a pointer to a (cf file defined) argument vector. 617 ** 618 ** Returns: 619 ** mapped host name 620 ** FALSE otherwise. 621 ** 622 ** Side Effects: 623 ** Looks up the host specified in hbuf. If it is not 624 ** the canonical name for that host, replace it with 625 ** the canonical name. If the name is unknown, or it 626 ** is already the canonical name, leave it unchanged. 627 */ 628 629 /*ARGSUSED*/ 630 char * 631 maphostname(hbuf, hbsize, avp) 632 char *hbuf; 633 int hbsize; 634 char **avp; 635 { 636 return NULL; 637 } 638 639 #endif DAEMON 640