1 /* Copyright 1988,1990,1993,1994 by Paul Vixie 2 * All rights reserved 3 * 4 * Distribute freely, except: don't remove my name from the source or 5 * documentation (don't take credit for my work), mark your changes (don't 6 * get me blamed for your possible bugs), don't alter or remove this 7 * notice. May be sold if buildable source is provided to buyer. No 8 * warrantee of any kind, express or implied, is included with this 9 * software; use at your own risk, responsibility for damages (if any) to 10 * anyone resulting from the use of this software rests entirely with the 11 * user. 12 * 13 * Send bug reports, bug fixes, enhancements, requests, flames, etc., and 14 * I'll try to keep a version up to date. I can be reached as follows: 15 * Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul 16 */ 17 18 #if !defined(lint) && !defined(LINT) 19 static const char rcsid[] = 20 "$FreeBSD$"; 21 #endif 22 23 24 #include "cron.h" 25 #include <sys/signal.h> 26 #if defined(sequent) 27 # include <sys/universe.h> 28 #endif 29 #if defined(SYSLOG) 30 # include <syslog.h> 31 #endif 32 #if defined(LOGIN_CAP) 33 # include <login_cap.h> 34 #endif 35 36 37 static void child_process __P((entry *, user *)), 38 do_univ __P((user *)); 39 40 41 void 42 do_command(e, u) 43 entry *e; 44 user *u; 45 { 46 Debug(DPROC, ("[%d] do_command(%s, (%s,%d,%d))\n", 47 getpid(), e->cmd, u->name, e->uid, e->gid)) 48 49 /* fork to become asynchronous -- parent process is done immediately, 50 * and continues to run the normal cron code, which means return to 51 * tick(). the child and grandchild don't leave this function, alive. 52 * 53 * vfork() is unsuitable, since we have much to do, and the parent 54 * needs to be able to run off and fork other processes. 55 */ 56 switch (fork()) { 57 case -1: 58 log_it("CRON",getpid(),"error","can't fork"); 59 break; 60 case 0: 61 /* child process */ 62 acquire_daemonlock(1); 63 child_process(e, u); 64 Debug(DPROC, ("[%d] child process done, exiting\n", getpid())) 65 _exit(OK_EXIT); 66 break; 67 default: 68 /* parent process */ 69 break; 70 } 71 Debug(DPROC, ("[%d] main process returning to work\n", getpid())) 72 } 73 74 75 static void 76 child_process(e, u) 77 entry *e; 78 user *u; 79 { 80 int stdin_pipe[2], stdout_pipe[2]; 81 register char *input_data; 82 char *usernm, *mailto; 83 int children = 0; 84 # if defined(LOGIN_CAP) 85 struct passwd *pwd; 86 login_cap_t *lc; 87 # endif 88 89 Debug(DPROC, ("[%d] child_process('%s')\n", getpid(), e->cmd)) 90 91 /* mark ourselves as different to PS command watchers by upshifting 92 * our program name. This has no effect on some kernels. 93 */ 94 setproctitle("running job"); 95 96 /* discover some useful and important environment settings 97 */ 98 usernm = env_get("LOGNAME", e->envp); 99 mailto = env_get("MAILTO", e->envp); 100 101 #ifdef USE_SIGCHLD 102 /* our parent is watching for our death by catching SIGCHLD. we 103 * do not care to watch for our children's deaths this way -- we 104 * use wait() explictly. so we have to disable the signal (which 105 * was inherited from the parent). 106 */ 107 (void) signal(SIGCHLD, SIG_DFL); 108 #else 109 /* on system-V systems, we are ignoring SIGCLD. we have to stop 110 * ignoring it now or the wait() in cron_pclose() won't work. 111 * because of this, we have to wait() for our children here, as well. 112 */ 113 (void) signal(SIGCLD, SIG_DFL); 114 #endif /*BSD*/ 115 116 /* create some pipes to talk to our future child 117 */ 118 pipe(stdin_pipe); /* child's stdin */ 119 pipe(stdout_pipe); /* child's stdout */ 120 121 /* since we are a forked process, we can diddle the command string 122 * we were passed -- nobody else is going to use it again, right? 123 * 124 * if a % is present in the command, previous characters are the 125 * command, and subsequent characters are the additional input to 126 * the command. Subsequent %'s will be transformed into newlines, 127 * but that happens later. 128 * 129 * If there are escaped %'s, remove the escape character. 130 */ 131 /*local*/{ 132 register int escaped = FALSE; 133 register int ch; 134 register char *p; 135 136 for (input_data = p = e->cmd; (ch = *input_data); 137 input_data++, p++) { 138 if (p != input_data) 139 *p = ch; 140 if (escaped) { 141 if (ch == '%' || ch == '\\') 142 *--p = ch; 143 escaped = FALSE; 144 continue; 145 } 146 if (ch == '\\') { 147 escaped = TRUE; 148 continue; 149 } 150 if (ch == '%') { 151 *input_data++ = '\0'; 152 break; 153 } 154 } 155 *p = '\0'; 156 } 157 158 /* fork again, this time so we can exec the user's command. 159 */ 160 switch (vfork()) { 161 case -1: 162 log_it("CRON",getpid(),"error","can't vfork"); 163 exit(ERROR_EXIT); 164 /*NOTREACHED*/ 165 case 0: 166 Debug(DPROC, ("[%d] grandchild process Vfork()'ed\n", 167 getpid())) 168 169 if (e->uid == ROOT_UID) 170 Jitter = RootJitter; 171 if (Jitter != 0) { 172 srandom(getpid()); 173 sleep(random() % Jitter); 174 } 175 176 /* write a log message. we've waited this long to do it 177 * because it was not until now that we knew the PID that 178 * the actual user command shell was going to get and the 179 * PID is part of the log message. 180 */ 181 /*local*/{ 182 char *x = mkprints((u_char *)e->cmd, strlen(e->cmd)); 183 184 log_it(usernm, getpid(), "CMD", x); 185 free(x); 186 } 187 188 /* that's the last thing we'll log. close the log files. 189 */ 190 #ifdef SYSLOG 191 closelog(); 192 #endif 193 194 /* get new pgrp, void tty, etc. 195 */ 196 (void) setsid(); 197 198 /* close the pipe ends that we won't use. this doesn't affect 199 * the parent, who has to read and write them; it keeps the 200 * kernel from recording us as a potential client TWICE -- 201 * which would keep it from sending SIGPIPE in otherwise 202 * appropriate circumstances. 203 */ 204 close(stdin_pipe[WRITE_PIPE]); 205 close(stdout_pipe[READ_PIPE]); 206 207 /* grandchild process. make std{in,out} be the ends of 208 * pipes opened by our daddy; make stderr go to stdout. 209 */ 210 close(STDIN); dup2(stdin_pipe[READ_PIPE], STDIN); 211 close(STDOUT); dup2(stdout_pipe[WRITE_PIPE], STDOUT); 212 close(STDERR); dup2(STDOUT, STDERR); 213 214 /* close the pipes we just dup'ed. The resources will remain. 215 */ 216 close(stdin_pipe[READ_PIPE]); 217 close(stdout_pipe[WRITE_PIPE]); 218 219 /* set our login universe. Do this in the grandchild 220 * so that the child can invoke /usr/lib/sendmail 221 * without surprises. 222 */ 223 do_univ(u); 224 225 # if defined(LOGIN_CAP) 226 /* Set user's entire context, but skip the environment 227 * as cron provides a separate interface for this 228 */ 229 if ((pwd = getpwnam(usernm)) == NULL) 230 pwd = getpwuid(e->uid); 231 lc = NULL; 232 if (pwd != NULL) { 233 pwd->pw_gid = e->gid; 234 if (e->class != NULL) 235 lc = login_getclass(e->class); 236 } 237 if (pwd && 238 setusercontext(lc, pwd, e->uid, 239 LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETENV)) == 0) 240 (void) endpwent(); 241 else { 242 /* fall back to the old method */ 243 (void) endpwent(); 244 # endif 245 /* set our directory, uid and gid. Set gid first, 246 * since once we set uid, we've lost root privledges. 247 */ 248 setgid(e->gid); 249 # if defined(BSD) 250 initgroups(usernm, e->gid); 251 # endif 252 setlogin(usernm); 253 setuid(e->uid); /* we aren't root after this..*/ 254 #if defined(LOGIN_CAP) 255 } 256 if (lc != NULL) 257 login_close(lc); 258 #endif 259 chdir(env_get("HOME", e->envp)); 260 261 /* exec the command. 262 */ 263 { 264 char *shell = env_get("SHELL", e->envp); 265 266 # if DEBUGGING 267 if (DebugFlags & DTEST) { 268 fprintf(stderr, 269 "debug DTEST is on, not exec'ing command.\n"); 270 fprintf(stderr, 271 "\tcmd='%s' shell='%s'\n", e->cmd, shell); 272 _exit(OK_EXIT); 273 } 274 # endif /*DEBUGGING*/ 275 execle(shell, shell, "-c", e->cmd, (char *)0, e->envp); 276 warn("execl: couldn't exec `%s'", shell); 277 _exit(ERROR_EXIT); 278 } 279 break; 280 default: 281 /* parent process */ 282 break; 283 } 284 285 children++; 286 287 /* middle process, child of original cron, parent of process running 288 * the user's command. 289 */ 290 291 Debug(DPROC, ("[%d] child continues, closing pipes\n", getpid())) 292 293 /* close the ends of the pipe that will only be referenced in the 294 * grandchild process... 295 */ 296 close(stdin_pipe[READ_PIPE]); 297 close(stdout_pipe[WRITE_PIPE]); 298 299 /* 300 * write, to the pipe connected to child's stdin, any input specified 301 * after a % in the crontab entry. while we copy, convert any 302 * additional %'s to newlines. when done, if some characters were 303 * written and the last one wasn't a newline, write a newline. 304 * 305 * Note that if the input data won't fit into one pipe buffer (2K 306 * or 4K on most BSD systems), and the child doesn't read its stdin, 307 * we would block here. thus we must fork again. 308 */ 309 310 if (*input_data && fork() == 0) { 311 register FILE *out = fdopen(stdin_pipe[WRITE_PIPE], "w"); 312 register int need_newline = FALSE; 313 register int escaped = FALSE; 314 register int ch; 315 316 if (out == NULL) { 317 warn("fdopen failed in child2"); 318 _exit(ERROR_EXIT); 319 } 320 321 Debug(DPROC, ("[%d] child2 sending data to grandchild\n", getpid())) 322 323 /* close the pipe we don't use, since we inherited it and 324 * are part of its reference count now. 325 */ 326 close(stdout_pipe[READ_PIPE]); 327 328 /* translation: 329 * \% -> % 330 * % -> \n 331 * \x -> \x for all x != % 332 */ 333 while ((ch = *input_data++)) { 334 if (escaped) { 335 if (ch != '%') 336 putc('\\', out); 337 } else { 338 if (ch == '%') 339 ch = '\n'; 340 } 341 342 if (!(escaped = (ch == '\\'))) { 343 putc(ch, out); 344 need_newline = (ch != '\n'); 345 } 346 } 347 if (escaped) 348 putc('\\', out); 349 if (need_newline) 350 putc('\n', out); 351 352 /* close the pipe, causing an EOF condition. fclose causes 353 * stdin_pipe[WRITE_PIPE] to be closed, too. 354 */ 355 fclose(out); 356 357 Debug(DPROC, ("[%d] child2 done sending to grandchild\n", getpid())) 358 exit(0); 359 } 360 361 /* close the pipe to the grandkiddie's stdin, since its wicked uncle 362 * ernie back there has it open and will close it when he's done. 363 */ 364 close(stdin_pipe[WRITE_PIPE]); 365 366 children++; 367 368 /* 369 * read output from the grandchild. it's stderr has been redirected to 370 * it's stdout, which has been redirected to our pipe. if there is any 371 * output, we'll be mailing it to the user whose crontab this is... 372 * when the grandchild exits, we'll get EOF. 373 */ 374 375 Debug(DPROC, ("[%d] child reading output from grandchild\n", getpid())) 376 377 /*local*/{ 378 register FILE *in = fdopen(stdout_pipe[READ_PIPE], "r"); 379 register int ch; 380 381 if (in == NULL) { 382 warn("fdopen failed in child"); 383 _exit(ERROR_EXIT); 384 } 385 386 ch = getc(in); 387 if (ch != EOF) { 388 register FILE *mail; 389 register int bytes = 1; 390 int status = 0; 391 392 Debug(DPROC|DEXT, 393 ("[%d] got data (%x:%c) from grandchild\n", 394 getpid(), ch, ch)) 395 396 /* get name of recipient. this is MAILTO if set to a 397 * valid local username; USER otherwise. 398 */ 399 if (mailto) { 400 /* MAILTO was present in the environment 401 */ 402 if (!*mailto) { 403 /* ... but it's empty. set to NULL 404 */ 405 mailto = NULL; 406 } 407 } else { 408 /* MAILTO not present, set to USER. 409 */ 410 mailto = usernm; 411 } 412 413 /* if we are supposed to be mailing, MAILTO will 414 * be non-NULL. only in this case should we set 415 * up the mail command and subjects and stuff... 416 */ 417 418 if (mailto) { 419 register char **env; 420 auto char mailcmd[MAX_COMMAND]; 421 auto char hostname[MAXHOSTNAMELEN]; 422 423 (void) gethostname(hostname, MAXHOSTNAMELEN); 424 (void) snprintf(mailcmd, sizeof(mailcmd), 425 MAILARGS, MAILCMD); 426 if (!(mail = cron_popen(mailcmd, "w", e))) { 427 warn("%s", MAILCMD); 428 (void) _exit(ERROR_EXIT); 429 } 430 fprintf(mail, "From: %s (Cron Daemon)\n", usernm); 431 fprintf(mail, "To: %s\n", mailto); 432 fprintf(mail, "Subject: Cron <%s@%s> %s\n", 433 usernm, first_word(hostname, "."), 434 e->cmd); 435 # if defined(MAIL_DATE) 436 fprintf(mail, "Date: %s\n", 437 arpadate(&TargetTime)); 438 # endif /* MAIL_DATE */ 439 for (env = e->envp; *env; env++) 440 fprintf(mail, "X-Cron-Env: <%s>\n", 441 *env); 442 fprintf(mail, "\n"); 443 444 /* this was the first char from the pipe 445 */ 446 putc(ch, mail); 447 } 448 449 /* we have to read the input pipe no matter whether 450 * we mail or not, but obviously we only write to 451 * mail pipe if we ARE mailing. 452 */ 453 454 while (EOF != (ch = getc(in))) { 455 bytes++; 456 if (mailto) 457 putc(ch, mail); 458 } 459 460 /* only close pipe if we opened it -- i.e., we're 461 * mailing... 462 */ 463 464 if (mailto) { 465 Debug(DPROC, ("[%d] closing pipe to mail\n", 466 getpid())) 467 /* Note: the pclose will probably see 468 * the termination of the grandchild 469 * in addition to the mail process, since 470 * it (the grandchild) is likely to exit 471 * after closing its stdout. 472 */ 473 status = cron_pclose(mail); 474 } 475 476 /* if there was output and we could not mail it, 477 * log the facts so the poor user can figure out 478 * what's going on. 479 */ 480 if (mailto && status) { 481 char buf[MAX_TEMPSTR]; 482 483 snprintf(buf, sizeof(buf), 484 "mailed %d byte%s of output but got status 0x%04x\n", 485 bytes, (bytes==1)?"":"s", 486 status); 487 log_it(usernm, getpid(), "MAIL", buf); 488 } 489 490 } /*if data from grandchild*/ 491 492 Debug(DPROC, ("[%d] got EOF from grandchild\n", getpid())) 493 494 fclose(in); /* also closes stdout_pipe[READ_PIPE] */ 495 } 496 497 /* wait for children to die. 498 */ 499 for (; children > 0; children--) 500 { 501 WAIT_T waiter; 502 PID_T pid; 503 504 Debug(DPROC, ("[%d] waiting for grandchild #%d to finish\n", 505 getpid(), children)) 506 pid = wait(&waiter); 507 if (pid < OK) { 508 Debug(DPROC, ("[%d] no more grandchildren--mail written?\n", 509 getpid())) 510 break; 511 } 512 Debug(DPROC, ("[%d] grandchild #%d finished, status=%04x", 513 getpid(), pid, WEXITSTATUS(waiter))) 514 if (WIFSIGNALED(waiter) && WCOREDUMP(waiter)) 515 Debug(DPROC, (", dumped core")) 516 Debug(DPROC, ("\n")) 517 } 518 } 519 520 521 static void 522 do_univ(u) 523 user *u; 524 { 525 #if defined(sequent) 526 /* Dynix (Sequent) hack to put the user associated with 527 * the passed user structure into the ATT universe if 528 * necessary. We have to dig the gecos info out of 529 * the user's password entry to see if the magic 530 * "universe(att)" string is present. 531 */ 532 533 struct passwd *p; 534 char *s; 535 int i; 536 537 p = getpwuid(u->uid); 538 (void) endpwent(); 539 540 if (p == NULL) 541 return; 542 543 s = p->pw_gecos; 544 545 for (i = 0; i < 4; i++) 546 { 547 if ((s = strchr(s, ',')) == NULL) 548 return; 549 s++; 550 } 551 if (strcmp(s, "universe(att)")) 552 return; 553 554 (void) universe(U_ATT); 555 #endif 556 } 557