Merge branch 'master' of ssh://crater.dragonflybsd.org/repository/git/dragonfly
[dragonfly.git] / libexec / atrun / atrun.c
blob92299501d9ffa25546eeb06a7acd1504b9686cc1
1 /*
2 * atrun.c - run jobs queued by at; run with root privileges.
3 * Copyright (C) 1993, 1994 Thomas Koenig
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. The name of the author(s) may not be used to endorse or promote
11 * products derived from this software without specific prior written
12 * permission.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 * $FreeBSD: src/libexec/atrun/atrun.c,v 1.26 2007/06/15 12:02:16 yar Exp $
26 * $DragonFly: src/libexec/atrun/atrun.c,v 1.5 2004/09/20 19:32:19 joerg Exp $
29 /* System Headers */
31 #include <sys/fcntl.h>
32 #include <sys/types.h>
33 #include <sys/stat.h>
34 #include <sys/wait.h>
35 #include <sys/param.h>
36 #include <ctype.h>
37 #include <dirent.h>
38 #include <err.h>
39 #include <grp.h>
40 #include <pwd.h>
41 #include <signal.h>
42 #include <stdarg.h>
43 #include <stddef.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <syslog.h>
48 #include <time.h>
49 #include <unistd.h>
50 #include <utmp.h>
51 #include <paths.h>
52 #ifdef LOGIN_CAP
53 #include <login_cap.h>
54 #endif
55 #ifdef PAM
56 #include <security/pam_appl.h>
57 #include <security/openpam.h>
58 #endif
60 #if (MAXLOGNAME-1) > UT_NAMESIZE
61 #define LOGNAMESIZE UT_NAMESIZE
62 #else
63 #define LOGNAMESIZE (MAXLOGNAME-1)
64 #endif
66 /* Local headers */
68 #include "gloadavg.h"
69 #include "privs.h"
71 /* Macros */
73 #ifndef ATJOB_DIR
74 #define ATJOB_DIR "/usr/spool/atjobs/"
75 #endif
77 #ifndef ATSPOOL_DIR
78 #define ATSPOOL_DIR "/usr/spool/atspool/"
79 #endif
81 #ifndef LOADAVG_MX
82 #define LOADAVG_MX 1.5
83 #endif
85 uid_t real_uid, effective_uid;
86 gid_t real_gid, effective_gid;
88 /* File scope variables */
90 static const char * const atrun = "atrun"; /* service name for syslog etc. */
91 static int debug = 0;
93 void perr(const char *fmt, ...);
94 void perrx(const char *fmt, ...);
95 static void usage(void);
97 /* Local functions */
98 static int
99 write_string(int fd, const char* a)
101 return write(fd, a, strlen(a));
104 #undef DEBUG_FORK
105 #ifdef DEBUG_FORK
106 static pid_t
107 myfork(void)
109 pid_t res;
110 res = fork();
111 if (res == 0)
112 kill(getpid(),SIGSTOP);
113 return res;
116 #define fork myfork
117 #endif
119 static void
120 run_file(const char *filename, uid_t uid, gid_t gid)
122 /* Run a file by spawning off a process which redirects I/O,
123 * spawns a subshell, then waits for it to complete and sends
124 * mail to the user.
126 pid_t pid;
127 int fd_out, fd_in;
128 int queue;
129 char mailbuf[LOGNAMESIZE + 1], fmt[49];
130 char *mailname = NULL;
131 FILE *stream;
132 int send_mail = 0;
133 struct stat buf, lbuf;
134 off_t size;
135 struct passwd *pentry;
136 int fflags;
137 uid_t nuid;
138 gid_t ngid;
139 #ifdef PAM
140 pam_handle_t *pamh = NULL;
141 int pam_err;
142 struct pam_conv pamc = {
143 .conv = openpam_nullconv,
144 .appdata_ptr = NULL
146 #endif
148 PRIV_START
150 if (chmod(filename, S_IRUSR) != 0)
152 perr("cannot change file permissions");
155 PRIV_END
157 pid = fork();
158 if (pid == -1)
159 perr("cannot fork");
161 else if (pid != 0)
162 return;
164 /* Let's see who we mail to. Hopefully, we can read it from
165 * the command file; if not, send it to the owner, or, failing that,
166 * to root.
169 pentry = getpwuid(uid);
170 if (pentry == NULL)
171 perrx("Userid %lu not found - aborting job %s",
172 (unsigned long) uid, filename);
174 #ifdef PAM
175 PRIV_START
177 pam_err = pam_start(atrun, pentry->pw_name, &pamc, &pamh);
178 if (pam_err != PAM_SUCCESS)
179 perrx("cannot start PAM: %s", pam_strerror(pamh, pam_err));
181 pam_err = pam_acct_mgmt(pamh, PAM_SILENT);
182 /* Expired password shouldn't prevent the job from running. */
183 if (pam_err != PAM_SUCCESS && pam_err != PAM_NEW_AUTHTOK_REQD)
184 perrx("Account %s (userid %lu) unavailable for job %s: %s",
185 pentry->pw_name, (unsigned long)uid,
186 filename, pam_strerror(pamh, pam_err));
188 pam_end(pamh, pam_err);
190 PRIV_END
191 #endif /* PAM */
193 PRIV_START
195 stream=fopen(filename, "r");
197 PRIV_END
199 if (stream == NULL)
200 perr("cannot open input file");
202 if ((fd_in = dup(fileno(stream))) <0)
203 perr("error duplicating input file descriptor");
205 if (fstat(fd_in, &buf) == -1)
206 perr("error in fstat of input file descriptor");
208 if (lstat(filename, &lbuf) == -1)
209 perr("error in fstat of input file");
211 if (S_ISLNK(lbuf.st_mode))
212 perrx("Symbolic link encountered in job %s - aborting", filename);
214 if ((lbuf.st_dev != buf.st_dev) || (lbuf.st_ino != buf.st_ino) ||
215 (lbuf.st_uid != buf.st_uid) || (lbuf.st_gid != buf.st_gid) ||
216 (lbuf.st_size!=buf.st_size))
217 perrx("Somebody changed files from under us for job %s - aborting",
218 filename);
220 if (buf.st_nlink > 1)
221 perrx("Somebody is trying to run a linked script for job %s", filename);
223 if ((fflags = fcntl(fd_in, F_GETFD)) <0)
224 perr("error in fcntl");
226 fcntl(fd_in, F_SETFD, fflags & ~FD_CLOEXEC);
228 snprintf(fmt, sizeof(fmt),
229 "#!/bin/sh\n# atrun uid=%%ld gid=%%ld\n# mail %%%ds %%d",
230 LOGNAMESIZE);
232 if (fscanf(stream, fmt, &nuid, &ngid, mailbuf, &send_mail) != 4)
233 perrx("File %s is in wrong format - aborting", filename);
235 if (mailbuf[0] == '-')
236 perrx("Illegal mail name %s in %s", mailbuf, filename);
238 mailname = mailbuf;
240 if (nuid != uid)
241 perrx("Job %s - userid %ld does not match file uid %lu",
242 filename, nuid, (unsigned long)uid);
244 if (ngid != gid)
245 perrx("Job %s - groupid %ld does not match file gid %lu",
246 filename, ngid, (unsigned long)gid);
248 fclose(stream);
250 if (chdir(ATSPOOL_DIR) < 0)
251 perr("cannot chdir to %s", ATSPOOL_DIR);
253 /* Create a file to hold the output of the job we are about to run.
254 * Write the mail header.
256 if((fd_out=open(filename,
257 O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR)) < 0)
258 perr("cannot create output file");
260 write_string(fd_out, "Subject: Output from your job ");
261 write_string(fd_out, filename);
262 write_string(fd_out, "\n\n");
263 fstat(fd_out, &buf);
264 size = buf.st_size;
266 close(STDIN_FILENO);
267 close(STDOUT_FILENO);
268 close(STDERR_FILENO);
270 pid = fork();
271 if (pid < 0)
272 perr("error in fork");
274 else if (pid == 0)
276 char *nul = NULL;
277 char **nenvp = &nul;
279 /* Set up things for the child; we want standard input from the input file,
280 * and standard output and error sent to our output file.
283 if (lseek(fd_in, (off_t) 0, SEEK_SET) < 0)
284 perr("error in lseek");
286 if (dup(fd_in) != STDIN_FILENO)
287 perr("error in I/O redirection");
289 if (dup(fd_out) != STDOUT_FILENO)
290 perr("error in I/O redirection");
292 if (dup(fd_out) != STDERR_FILENO)
293 perr("error in I/O redirection");
295 close(fd_in);
296 close(fd_out);
297 if (chdir(ATJOB_DIR) < 0)
298 perr("cannot chdir to %s", ATJOB_DIR);
300 queue = *filename;
302 PRIV_START
304 nice(tolower(queue) - 'a');
306 #ifdef LOGIN_CAP
308 * For simplicity and safety, set all aspects of the user context
309 * except for a selected subset: Don't set priority, which was
310 * set based on the queue file name according to the tradition.
311 * Don't bother to set environment, including path vars, either
312 * because it will be discarded anyway. Although the job file
313 * should set umask, preset it here just in case.
315 if (setusercontext(NULL, pentry, uid, LOGIN_SETALL &
316 ~(LOGIN_SETPRIORITY | LOGIN_SETPATH | LOGIN_SETENV)) != 0)
317 exit(EXIT_FAILURE); /* setusercontext() logged the error */
318 #else /* LOGIN_CAP */
319 if (initgroups(pentry->pw_name,pentry->pw_gid))
320 perr("cannot init group access list");
322 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
323 perr("cannot change group");
325 if (setlogin(pentry->pw_name))
326 perr("cannot set login name");
328 if (setuid(uid) < 0 || seteuid(uid) < 0)
329 perr("cannot set user id");
330 #endif /* LOGIN_CAP */
332 if (chdir(pentry->pw_dir))
333 chdir("/");
335 if(execle("/bin/sh","sh",NULL, nenvp) != 0)
336 perr("exec failed for /bin/sh");
338 PRIV_END
340 /* We're the parent. Let's wait.
342 close(fd_in);
343 close(fd_out);
344 waitpid(pid, NULL, 0);
346 /* Send mail. Unlink the output file first, so it is deleted after
347 * the run.
349 stat(filename, &buf);
350 if (open(filename, O_RDONLY) != STDIN_FILENO)
351 perr("open of jobfile failed");
353 unlink(filename);
354 if ((buf.st_size != size) || send_mail)
356 PRIV_START
358 #ifdef LOGIN_CAP
360 * This time set full context to run the mailer.
362 if (setusercontext(NULL, pentry, uid, LOGIN_SETALL) != 0)
363 exit(EXIT_FAILURE); /* setusercontext() logged the error */
364 #else /* LOGIN_CAP */
365 if (initgroups(pentry->pw_name,pentry->pw_gid))
366 perr("cannot init group access list");
368 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
369 perr("cannot change group");
371 if (setlogin(pentry->pw_name))
372 perr("cannot set login name");
374 if (setuid(uid) < 0 || seteuid(uid) < 0)
375 perr("cannot set user id");
376 #endif /* LOGIN_CAP */
378 if (chdir(pentry->pw_dir))
379 chdir("/");
381 execl(_PATH_SENDMAIL, "sendmail", "-F", "Atrun Service",
382 "-odi", "-oem",
383 mailname, NULL);
384 perr("exec failed for mail command");
386 PRIV_END
388 exit(EXIT_SUCCESS);
391 /* Global functions */
393 /* Needed in gloadavg.c */
394 void
395 perr(const char *fmt, ...)
397 const char * const fmtadd = ": %m";
398 char nfmt[strlen(fmt) + strlen(fmtadd) + 1];
399 va_list ap;
401 va_start(ap, fmt);
402 if (debug)
404 vwarn(fmt, ap);
406 else
408 snprintf(nfmt, sizeof(nfmt), "%s%s", fmt, fmtadd);
409 vsyslog(LOG_ERR, nfmt, ap);
411 va_end(ap);
413 exit(EXIT_FAILURE);
416 void
417 perrx(const char *fmt, ...)
419 va_list ap;
421 va_start(ap, fmt);
422 if (debug)
423 vwarnx(fmt, ap);
424 else
425 vsyslog(LOG_ERR, fmt, ap);
426 va_end(ap);
428 exit(EXIT_FAILURE);
432 main(int argc, char *argv[])
434 /* Browse through ATJOB_DIR, checking all the jobfiles wether they should
435 * be executed and or deleted. The queue is coded into the first byte of
436 * the job filename, the date (in minutes since Eon) as a hex number in the
437 * following eight bytes, followed by a dot and a serial number. A file
438 * which has not been executed yet is denoted by its execute - bit set.
439 * For those files which are to be executed, run_file() is called, which forks
440 * off a child which takes care of I/O redirection, forks off another child
441 * for execution and yet another one, optionally, for sending mail.
442 * Files which already have run are removed during the next invocation.
444 DIR *spool;
445 struct dirent *dirent;
446 struct stat buf;
447 unsigned long ctm;
448 unsigned long jobno;
449 char queue;
450 time_t now, run_time;
451 char batch_name[] = "Z2345678901234";
452 uid_t batch_uid;
453 gid_t batch_gid;
454 int c;
455 int run_batch;
456 double load_avg = LOADAVG_MX;
458 /* We don't need root privileges all the time; running under uid and gid daemon
459 * is fine.
462 RELINQUISH_PRIVS_ROOT(DAEMON_UID, DAEMON_GID)
464 openlog(atrun, LOG_PID, LOG_CRON);
466 opterr = 0;
467 while((c=getopt(argc, argv, "dl:"))!= -1)
469 switch (c)
471 case 'l':
472 if (sscanf(optarg, "%lf", &load_avg) != 1)
473 perr("garbled option -l");
474 if (load_avg <= 0.)
475 load_avg = LOADAVG_MX;
476 break;
478 case 'd':
479 debug ++;
480 break;
482 case '?':
483 default:
484 usage();
488 if (chdir(ATJOB_DIR) != 0)
489 perr("cannot change to %s", ATJOB_DIR);
491 /* Main loop. Open spool directory for reading and look over all the
492 * files in there. If the filename indicates that the job should be run
493 * and the x bit is set, fork off a child which sets its user and group
494 * id to that of the files and exec a /bin/sh which executes the shell
495 * script. Unlink older files if they should no longer be run. For
496 * deletion, their r bit has to be turned on.
498 * Also, pick the oldest batch job to run, at most one per invocation of
499 * atrun.
501 if ((spool = opendir(".")) == NULL)
502 perr("cannot read %s", ATJOB_DIR);
504 now = time(NULL);
505 run_batch = 0;
506 batch_uid = (uid_t) -1;
507 batch_gid = (gid_t) -1;
509 while ((dirent = readdir(spool)) != NULL) {
510 if (stat(dirent->d_name,&buf) != 0)
511 perr("cannot stat in %s", ATJOB_DIR);
513 /* We don't want directories
515 if (!S_ISREG(buf.st_mode))
516 continue;
518 if (sscanf(dirent->d_name,"%c%5lx%8lx",&queue,&jobno,&ctm) != 3)
519 continue;
521 run_time = (time_t) ctm*60;
523 if ((S_IXUSR & buf.st_mode) && (run_time <=now)) {
524 if (isupper(queue) && (strcmp(batch_name,dirent->d_name) > 0)) {
525 run_batch = 1;
526 strlcpy(batch_name, dirent->d_name, sizeof(batch_name));
527 batch_uid = buf.st_uid;
528 batch_gid = buf.st_gid;
531 /* The file is executable and old enough
533 if (islower(queue))
534 run_file(dirent->d_name, buf.st_uid, buf.st_gid);
536 /* Delete older files
538 if ((run_time < now) && !(S_IXUSR & buf.st_mode) && (S_IRUSR & buf.st_mode))
539 unlink(dirent->d_name);
541 /* run the single batch file, if any
543 if (run_batch && (gloadavg() < load_avg))
544 run_file(batch_name, batch_uid, batch_gid);
546 closelog();
547 exit(EXIT_SUCCESS);
550 static void
551 usage(void)
553 if (debug)
554 fprintf(stderr, "usage: atrun [-l load_avg] [-d]\n");
555 else
556 syslog(LOG_ERR, "usage: atrun [-l load_avg] [-d]");
558 exit(EXIT_FAILURE);