1 /* Copyright 1988,1990,1993,1994 by Paul Vixie
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
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
17 * $FreeBSD: src/usr.sbin/cron/cron/do_command.c,v 1.15.2.5 2001/05/04 00:59:40 peter Exp $
18 * $DragonFly: src/usr.sbin/cron/cron/do_command.c,v 1.6 2004/12/18 22:48:03 swildner Exp $
22 #include <sys/signal.h>
24 # include <sys/universe.h>
29 #if defined(LOGIN_CAP)
30 # include <login_cap.h>
34 static void child_process(entry *, user *),
39 do_command(entry *e, user *u)
41 Debug(DPROC, ("[%d] do_command(%s, (%s,%d,%d))\n",
42 getpid(), e->cmd, u->name, e->uid, e->gid))
44 /* fork to become asynchronous -- parent process is done immediately,
45 * and continues to run the normal cron code, which means return to
46 * tick(). the child and grandchild don't leave this function, alive.
48 * vfork() is unsuitable, since we have much to do, and the parent
49 * needs to be able to run off and fork other processes.
53 log_it("CRON",getpid(),"error","can't fork");
57 acquire_daemonlock(1);
59 Debug(DPROC, ("[%d] child process done, exiting\n", getpid()))
66 Debug(DPROC, ("[%d] main process returning to work\n", getpid()))
71 child_process(entry *e, user *u)
73 int stdin_pipe[2], stdout_pipe[2];
75 char *usernm, *mailto;
77 # if defined(LOGIN_CAP)
82 Debug(DPROC, ("[%d] child_process('%s')\n", getpid(), e->cmd))
84 /* mark ourselves as different to PS command watchers by upshifting
85 * our program name. This has no effect on some kernels.
87 setproctitle("running job");
89 /* discover some useful and important environment settings
91 usernm = env_get("LOGNAME", e->envp);
92 mailto = env_get("MAILTO", e->envp);
95 /* our parent is watching for our death by catching SIGCHLD. we
96 * do not care to watch for our children's deaths this way -- we
97 * use wait() explictly. so we have to disable the signal (which
98 * was inherited from the parent).
100 signal(SIGCHLD, SIG_DFL);
102 /* on system-V systems, we are ignoring SIGCLD. we have to stop
103 * ignoring it now or the wait() in cron_pclose() won't work.
104 * because of this, we have to wait() for our children here, as well.
106 signal(SIGCLD, SIG_DFL);
109 /* create some pipes to talk to our future child
111 pipe(stdin_pipe); /* child's stdin */
112 pipe(stdout_pipe); /* child's stdout */
114 /* since we are a forked process, we can diddle the command string
115 * we were passed -- nobody else is going to use it again, right?
117 * if a % is present in the command, previous characters are the
118 * command, and subsequent characters are the additional input to
119 * the command. Subsequent %'s will be transformed into newlines,
120 * but that happens later.
122 * If there are escaped %'s, remove the escape character.
129 for (input_data = p = e->cmd; (ch = *input_data);
134 if (ch == '%' || ch == '\\')
144 *input_data++ = '\0';
151 /* fork again, this time so we can exec the user's command.
155 log_it("CRON",getpid(),"error","can't vfork");
159 Debug(DPROC, ("[%d] grandchild process Vfork()'ed\n",
162 /* write a log message. we've waited this long to do it
163 * because it was not until now that we knew the PID that
164 * the actual user command shell was going to get and the
165 * PID is part of the log message.
168 char *x = mkprints((u_char *)e->cmd, strlen(e->cmd));
170 log_it(usernm, getpid(), "CMD", x);
174 /* that's the last thing we'll log. close the log files.
180 /* get new pgrp, void tty, etc.
184 /* close the pipe ends that we won't use. this doesn't affect
185 * the parent, who has to read and write them; it keeps the
186 * kernel from recording us as a potential client TWICE --
187 * which would keep it from sending SIGPIPE in otherwise
188 * appropriate circumstances.
190 close(stdin_pipe[WRITE_PIPE]);
191 close(stdout_pipe[READ_PIPE]);
193 /* grandchild process. make std{in,out} be the ends of
194 * pipes opened by our daddy; make stderr go to stdout.
196 close(STDIN); dup2(stdin_pipe[READ_PIPE], STDIN);
197 close(STDOUT); dup2(stdout_pipe[WRITE_PIPE], STDOUT);
198 close(STDERR); dup2(STDOUT, STDERR);
200 /* close the pipes we just dup'ed. The resources will remain.
202 close(stdin_pipe[READ_PIPE]);
203 close(stdout_pipe[WRITE_PIPE]);
205 /* set our login universe. Do this in the grandchild
206 * so that the child can invoke /usr/lib/sendmail
211 # if defined(LOGIN_CAP)
212 /* Set user's entire context, but skip the environment
213 * as cron provides a separate interface for this
215 if ((pwd = getpwnam(usernm)) == NULL)
216 pwd = getpwuid(e->uid);
219 pwd->pw_gid = e->gid;
220 if (e->class != NULL)
221 lc = login_getclass(e->class);
224 setusercontext(lc, pwd, e->uid,
225 LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETENV)) == 0)
228 /* fall back to the old method */
231 /* set our directory, uid and gid. Set gid first,
232 * since once we set uid, we've lost root privledges.
236 initgroups(usernm, e->gid);
239 setuid(e->uid); /* we aren't root after this..*/
240 #if defined(LOGIN_CAP)
245 chdir(env_get("HOME", e->envp));
250 char *shell = env_get("SHELL", e->envp);
253 if (DebugFlags & DTEST) {
255 "debug DTEST is on, not exec'ing command.\n");
257 "\tcmd='%s' shell='%s'\n", e->cmd, shell);
260 # endif /*DEBUGGING*/
261 execle(shell, shell, "-c", e->cmd, (char *)0, e->envp);
262 warn("execl: couldn't exec `%s'", shell);
273 /* middle process, child of original cron, parent of process running
274 * the user's command.
277 Debug(DPROC, ("[%d] child continues, closing pipes\n", getpid()))
279 /* close the ends of the pipe that will only be referenced in the
280 * grandchild process...
282 close(stdin_pipe[READ_PIPE]);
283 close(stdout_pipe[WRITE_PIPE]);
286 * write, to the pipe connected to child's stdin, any input specified
287 * after a % in the crontab entry. while we copy, convert any
288 * additional %'s to newlines. when done, if some characters were
289 * written and the last one wasn't a newline, write a newline.
291 * Note that if the input data won't fit into one pipe buffer (2K
292 * or 4K on most BSD systems), and the child doesn't read its stdin,
293 * we would block here. thus we must fork again.
296 if (*input_data && fork() == 0) {
298 int need_newline = FALSE;
302 out = fdopen(stdin_pipe[WRITE_PIPE], "w");
304 warn("fdopen failed in child2");
308 Debug(DPROC, ("[%d] child2 sending data to grandchild\n", getpid()))
310 /* close the pipe we don't use, since we inherited it and
311 * are part of its reference count now.
313 close(stdout_pipe[READ_PIPE]);
318 * \x -> \x for all x != %
320 while ((ch = *input_data++)) {
329 if (!(escaped = (ch == '\\'))) {
331 need_newline = (ch != '\n');
339 /* close the pipe, causing an EOF condition. fclose causes
340 * stdin_pipe[WRITE_PIPE] to be closed, too.
344 Debug(DPROC, ("[%d] child2 done sending to grandchild\n", getpid()))
348 /* close the pipe to the grandkiddie's stdin, since its wicked uncle
349 * ernie back there has it open and will close it when he's done.
351 close(stdin_pipe[WRITE_PIPE]);
356 * read output from the grandchild. it's stderr has been redirected to
357 * it's stdout, which has been redirected to our pipe. if there is any
358 * output, we'll be mailing it to the user whose crontab this is...
359 * when the grandchild exits, we'll get EOF.
362 Debug(DPROC, ("[%d] child reading output from grandchild\n", getpid()))
368 in = fdopen(stdout_pipe[READ_PIPE], "r");
370 warn("fdopen failed in child");
381 ("[%d] got data (%x:%c) from grandchild\n",
384 /* get name of recipient. this is MAILTO if set to a
385 * valid local username; USER otherwise.
388 /* MAILTO was present in the environment
391 /* ... but it's empty. set to NULL
396 /* MAILTO not present, set to USER.
401 /* if we are supposed to be mailing, MAILTO will
402 * be non-NULL. only in this case should we set
403 * up the mail command and subjects and stuff...
408 char mailcmd[MAX_COMMAND];
409 char hostname[MAXHOSTNAMELEN];
411 gethostname(hostname, MAXHOSTNAMELEN);
412 snprintf(mailcmd, sizeof(mailcmd),
414 if (!(mail = cron_popen(mailcmd, "w", e))) {
418 fprintf(mail, "From: %s (Cron Daemon)\n", usernm);
419 fprintf(mail, "To: %s\n", mailto);
420 fprintf(mail, "Subject: Cron <%s@%s> %s\n",
421 usernm, first_word(hostname, "."),
423 # if defined(MAIL_DATE)
424 fprintf(mail, "Date: %s\n",
425 arpadate(&TargetTime));
426 # endif /* MAIL_DATE */
427 for (env = e->envp; *env; env++)
428 fprintf(mail, "X-Cron-Env: <%s>\n",
432 /* this was the first char from the pipe
437 /* we have to read the input pipe no matter whether
438 * we mail or not, but obviously we only write to
439 * mail pipe if we ARE mailing.
442 while (EOF != (ch = getc(in))) {
448 /* only close pipe if we opened it -- i.e., we're
453 Debug(DPROC, ("[%d] closing pipe to mail\n",
455 /* Note: the pclose will probably see
456 * the termination of the grandchild
457 * in addition to the mail process, since
458 * it (the grandchild) is likely to exit
459 * after closing its stdout.
461 status = cron_pclose(mail);
464 /* if there was output and we could not mail it,
465 * log the facts so the poor user can figure out
468 if (mailto && status) {
469 char buf[MAX_TEMPSTR];
471 snprintf(buf, sizeof(buf),
472 "mailed %d byte%s of output but got status 0x%04x\n",
473 bytes, (bytes==1)?"":"s",
475 log_it(usernm, getpid(), "MAIL", buf);
478 } /*if data from grandchild*/
480 Debug(DPROC, ("[%d] got EOF from grandchild\n", getpid()))
482 fclose(in); /* also closes stdout_pipe[READ_PIPE] */
485 /* wait for children to die.
487 for (; children > 0; children--)
492 Debug(DPROC, ("[%d] waiting for grandchild #%d to finish\n",
496 Debug(DPROC, ("[%d] no more grandchildren--mail written?\n",
500 Debug(DPROC, ("[%d] grandchild #%d finished, status=%04x",
501 getpid(), pid, WEXITSTATUS(waiter)))
502 if (WIFSIGNALED(waiter) && WCOREDUMP(waiter))
503 Debug(DPROC, (", dumped core"))
513 /* Dynix (Sequent) hack to put the user associated with
514 * the passed user structure into the ATT universe if
515 * necessary. We have to dig the gecos info out of
516 * the user's password entry to see if the magic
517 * "universe(att)" string is present.
524 p = getpwuid(u->uid);
532 for (i = 0; i < 4; i++)
534 if ((s = strchr(s, ',')) == NULL)
538 if (strcmp(s, "universe(att)"))