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: src/usr.sbin/cron/cron/do_command.c,v 1.15.2.5 2001/05/04 00:59:40 peter Exp $"; 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 /* write a log message. we've waited this long to do it 170 * because it was not until now that we knew the PID that 171 * the actual user command shell was going to get and the 172 * PID is part of the log message. 173 */ 174 /*local*/{ 175 char *x = mkprints((u_char *)e->cmd, strlen(e->cmd)); 176 177 log_it(usernm, getpid(), "CMD", x); 178 free(x); 179 } 180 181 /* that's the last thing we'll log. close the log files. 182 */ 183 #ifdef SYSLOG 184 closelog(); 185 #endif 186 187 /* get new pgrp, void tty, etc. 188 */ 189 (void) setsid(); 190 191 /* close the pipe ends that we won't use. this doesn't affect 192 * the parent, who has to read and write them; it keeps the 193 * kernel from recording us as a potential client TWICE -- 194 * which would keep it from sending SIGPIPE in otherwise 195 * appropriate circumstances. 196 */ 197 close(stdin_pipe[WRITE_PIPE]); 198 close(stdout_pipe[READ_PIPE]); 199 200 /* grandchild process. make std{in,out} be the ends of 201 * pipes opened by our daddy; make stderr go to stdout. 202 */ 203 close(STDIN); dup2(stdin_pipe[READ_PIPE], STDIN); 204 close(STDOUT); dup2(stdout_pipe[WRITE_PIPE], STDOUT); 205 close(STDERR); dup2(STDOUT, STDERR); 206 207 /* close the pipes we just dup'ed. The resources will remain. 208 */ 209 close(stdin_pipe[READ_PIPE]); 210 close(stdout_pipe[WRITE_PIPE]); 211 212 /* set our login universe. Do this in the grandchild 213 * so that the child can invoke /usr/lib/sendmail 214 * without surprises. 215 */ 216 do_univ(u); 217 218 # if defined(LOGIN_CAP) 219 /* Set user's entire context, but skip the environment 220 * as cron provides a separate interface for this 221 */ 222 if ((pwd = getpwnam(usernm)) == NULL) 223 pwd = getpwuid(e->uid); 224 lc = NULL; 225 if (pwd != NULL) { 226 pwd->pw_gid = e->gid; 227 if (e->class != NULL) 228 lc = login_getclass(e->class); 229 } 230 if (pwd && 231 setusercontext(lc, pwd, e->uid, 232 LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETENV)) == 0) 233 (void) endpwent(); 234 else { 235 /* fall back to the old method */ 236 (void) endpwent(); 237 # endif 238 /* set our directory, uid and gid. Set gid first, 239 * since once we set uid, we've lost root privledges. 240 */ 241 setgid(e->gid); 242 # if defined(BSD) 243 initgroups(usernm, e->gid); 244 # endif 245 setlogin(usernm); 246 setuid(e->uid); /* we aren't root after this..*/ 247 #if defined(LOGIN_CAP) 248 } 249 if (lc != NULL) 250 login_close(lc); 251 #endif 252 chdir(env_get("HOME", e->envp)); 253 254 /* exec the command. 255 */ 256 { 257 char *shell = env_get("SHELL", e->envp); 258 259 # if DEBUGGING 260 if (DebugFlags & DTEST) { 261 fprintf(stderr, 262 "debug DTEST is on, not exec'ing command.\n"); 263 fprintf(stderr, 264 "\tcmd='%s' shell='%s'\n", e->cmd, shell); 265 _exit(OK_EXIT); 266 } 267 # endif /*DEBUGGING*/ 268 execle(shell, shell, "-c", e->cmd, (char *)0, e->envp); 269 warn("execl: couldn't exec `%s'", shell); 270 _exit(ERROR_EXIT); 271 } 272 break; 273 default: 274 /* parent process */ 275 break; 276 } 277 278 children++; 279 280 /* middle process, child of original cron, parent of process running 281 * the user's command. 282 */ 283 284 Debug(DPROC, ("[%d] child continues, closing pipes\n", getpid())) 285 286 /* close the ends of the pipe that will only be referenced in the 287 * grandchild process... 288 */ 289 close(stdin_pipe[READ_PIPE]); 290 close(stdout_pipe[WRITE_PIPE]); 291 292 /* 293 * write, to the pipe connected to child's stdin, any input specified 294 * after a % in the crontab entry. while we copy, convert any 295 * additional %'s to newlines. when done, if some characters were 296 * written and the last one wasn't a newline, write a newline. 297 * 298 * Note that if the input data won't fit into one pipe buffer (2K 299 * or 4K on most BSD systems), and the child doesn't read its stdin, 300 * we would block here. thus we must fork again. 301 */ 302 303 if (*input_data && fork() == 0) { 304 register FILE *out = fdopen(stdin_pipe[WRITE_PIPE], "w"); 305 register int need_newline = FALSE; 306 register int escaped = FALSE; 307 register int ch; 308 309 if (out == NULL) { 310 warn("fdopen failed in child2"); 311 _exit(ERROR_EXIT); 312 } 313 314 Debug(DPROC, ("[%d] child2 sending data to grandchild\n", getpid())) 315 316 /* close the pipe we don't use, since we inherited it and 317 * are part of its reference count now. 318 */ 319 close(stdout_pipe[READ_PIPE]); 320 321 /* translation: 322 * \% -> % 323 * % -> \n 324 * \x -> \x for all x != % 325 */ 326 while ((ch = *input_data++)) { 327 if (escaped) { 328 if (ch != '%') 329 putc('\\', out); 330 } else { 331 if (ch == '%') 332 ch = '\n'; 333 } 334 335 if (!(escaped = (ch == '\\'))) { 336 putc(ch, out); 337 need_newline = (ch != '\n'); 338 } 339 } 340 if (escaped) 341 putc('\\', out); 342 if (need_newline) 343 putc('\n', out); 344 345 /* close the pipe, causing an EOF condition. fclose causes 346 * stdin_pipe[WRITE_PIPE] to be closed, too. 347 */ 348 fclose(out); 349 350 Debug(DPROC, ("[%d] child2 done sending to grandchild\n", getpid())) 351 exit(0); 352 } 353 354 /* close the pipe to the grandkiddie's stdin, since its wicked uncle 355 * ernie back there has it open and will close it when he's done. 356 */ 357 close(stdin_pipe[WRITE_PIPE]); 358 359 children++; 360 361 /* 362 * read output from the grandchild. it's stderr has been redirected to 363 * it's stdout, which has been redirected to our pipe. if there is any 364 * output, we'll be mailing it to the user whose crontab this is... 365 * when the grandchild exits, we'll get EOF. 366 */ 367 368 Debug(DPROC, ("[%d] child reading output from grandchild\n", getpid())) 369 370 /*local*/{ 371 register FILE *in = fdopen(stdout_pipe[READ_PIPE], "r"); 372 register int ch = getc(in); 373 374 if (in == NULL) { 375 warn("fdopen failed in child"); 376 _exit(ERROR_EXIT); 377 } 378 379 if (ch != EOF) { 380 register FILE *mail; 381 register int bytes = 1; 382 int status = 0; 383 384 Debug(DPROC|DEXT, 385 ("[%d] got data (%x:%c) from grandchild\n", 386 getpid(), ch, ch)) 387 388 /* get name of recipient. this is MAILTO if set to a 389 * valid local username; USER otherwise. 390 */ 391 if (mailto) { 392 /* MAILTO was present in the environment 393 */ 394 if (!*mailto) { 395 /* ... but it's empty. set to NULL 396 */ 397 mailto = NULL; 398 } 399 } else { 400 /* MAILTO not present, set to USER. 401 */ 402 mailto = usernm; 403 } 404 405 /* if we are supposed to be mailing, MAILTO will 406 * be non-NULL. only in this case should we set 407 * up the mail command and subjects and stuff... 408 */ 409 410 if (mailto) { 411 register char **env; 412 auto char mailcmd[MAX_COMMAND]; 413 auto char hostname[MAXHOSTNAMELEN]; 414 415 (void) gethostname(hostname, MAXHOSTNAMELEN); 416 (void) snprintf(mailcmd, sizeof(mailcmd), 417 MAILARGS, MAILCMD); 418 if (!(mail = cron_popen(mailcmd, "w", e))) { 419 warn("%s", MAILCMD); 420 (void) _exit(ERROR_EXIT); 421 } 422 fprintf(mail, "From: %s (Cron Daemon)\n", usernm); 423 fprintf(mail, "To: %s\n", mailto); 424 fprintf(mail, "Subject: Cron <%s@%s> %s\n", 425 usernm, first_word(hostname, "."), 426 e->cmd); 427 # if defined(MAIL_DATE) 428 fprintf(mail, "Date: %s\n", 429 arpadate(&TargetTime)); 430 # endif /* MAIL_DATE */ 431 for (env = e->envp; *env; env++) 432 fprintf(mail, "X-Cron-Env: <%s>\n", 433 *env); 434 fprintf(mail, "\n"); 435 436 /* this was the first char from the pipe 437 */ 438 putc(ch, mail); 439 } 440 441 /* we have to read the input pipe no matter whether 442 * we mail or not, but obviously we only write to 443 * mail pipe if we ARE mailing. 444 */ 445 446 while (EOF != (ch = getc(in))) { 447 bytes++; 448 if (mailto) 449 putc(ch, mail); 450 } 451 452 /* only close pipe if we opened it -- i.e., we're 453 * mailing... 454 */ 455 456 if (mailto) { 457 Debug(DPROC, ("[%d] closing pipe to mail\n", 458 getpid())) 459 /* Note: the pclose will probably see 460 * the termination of the grandchild 461 * in addition to the mail process, since 462 * it (the grandchild) is likely to exit 463 * after closing its stdout. 464 */ 465 status = cron_pclose(mail); 466 } 467 468 /* if there was output and we could not mail it, 469 * log the facts so the poor user can figure out 470 * what's going on. 471 */ 472 if (mailto && status) { 473 char buf[MAX_TEMPSTR]; 474 475 snprintf(buf, sizeof(buf), 476 "mailed %d byte%s of output but got status 0x%04x\n", 477 bytes, (bytes==1)?"":"s", 478 status); 479 log_it(usernm, getpid(), "MAIL", buf); 480 } 481 482 } /*if data from grandchild*/ 483 484 Debug(DPROC, ("[%d] got EOF from grandchild\n", getpid())) 485 486 fclose(in); /* also closes stdout_pipe[READ_PIPE] */ 487 } 488 489 /* wait for children to die. 490 */ 491 for (; children > 0; children--) 492 { 493 WAIT_T waiter; 494 PID_T pid; 495 496 Debug(DPROC, ("[%d] waiting for grandchild #%d to finish\n", 497 getpid(), children)) 498 pid = wait(&waiter); 499 if (pid < OK) { 500 Debug(DPROC, ("[%d] no more grandchildren--mail written?\n", 501 getpid())) 502 break; 503 } 504 Debug(DPROC, ("[%d] grandchild #%d finished, status=%04x", 505 getpid(), pid, WEXITSTATUS(waiter))) 506 if (WIFSIGNALED(waiter) && WCOREDUMP(waiter)) 507 Debug(DPROC, (", dumped core")) 508 Debug(DPROC, ("\n")) 509 } 510 } 511 512 513 static void 514 do_univ(u) 515 user *u; 516 { 517 #if defined(sequent) 518 /* Dynix (Sequent) hack to put the user associated with 519 * the passed user structure into the ATT universe if 520 * necessary. We have to dig the gecos info out of 521 * the user's password entry to see if the magic 522 * "universe(att)" string is present. 523 */ 524 525 struct passwd *p; 526 char *s; 527 int i; 528 529 p = getpwuid(u->uid); 530 (void) endpwent(); 531 532 if (p == NULL) 533 return; 534 535 s = p->pw_gecos; 536 537 for (i = 0; i < 4; i++) 538 { 539 if ((s = strchr(s, ',')) == NULL) 540 return; 541 s++; 542 } 543 if (strcmp(s, "universe(att)")) 544 return; 545 546 (void) universe(U_ATT); 547 #endif 548 } 549