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
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
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 1.14.2.1 2001/03/05 10:53:23 kris Exp $
26 * $DragonFly: src/libexec/atrun/atrun.c,v 1.2 2003/06/17 04:27:07 dillon Exp $
31 #include <sys/fcntl.h>
32 #include <sys/types.h>
35 #include <sys/param.h>
56 #if (MAXLOGNAME-1) > UT_NAMESIZE
57 #define LOGNAMESIZE UT_NAMESIZE
59 #define LOGNAMESIZE (MAXLOGNAME-1)
71 #define ATJOB_DIR "/usr/spool/atjobs/"
75 #define ATSPOOL_DIR "/usr/spool/atspool/"
79 #define LOADAVG_MX 1.5
82 /* File scope variables */
86 void perr(const char *a);
87 static void usage __P((void));
91 write_string(int fd, const char* a)
93 return write(fd, a, strlen(a));
104 kill(getpid(),SIGSTOP);
112 run_file(const char *filename, uid_t uid, gid_t gid)
114 /* Run a file by by spawning off a process which redirects I/O,
115 * spawns a subshell, then waits for it to complete and sends
121 char mailbuf[LOGNAMESIZE + 1], fmt[49];
122 char *mailname = NULL;
125 struct stat buf, lbuf;
127 struct passwd *pentry;
135 if (chmod(filename, S_IRUSR) != 0)
137 perr("cannot change file permissions");
149 /* Let's see who we mail to. Hopefully, we can read it from
150 * the command file; if not, send it to the owner, or, failing that,
154 pentry = getpwuid(uid);
157 syslog(LOG_ERR,"Userid %lu not found - aborting job %s",
158 (unsigned long) uid, filename);
163 stream=fopen(filename, "r");
168 if (pentry->pw_expire && time(NULL) >= pentry->pw_expire)
170 syslog(LOG_ERR, "Userid %lu is expired - aborting job %s",
171 (unsigned long) uid, filename);
177 perr("cannot open input file");
179 if ((fd_in = dup(fileno(stream))) <0)
180 perr("error duplicating input file descriptor");
182 if (fstat(fd_in, &buf) == -1)
183 perr("error in fstat of input file descriptor");
185 if (lstat(filename, &lbuf) == -1)
186 perr("error in fstat of input file");
188 if (S_ISLNK(lbuf.st_mode)) {
189 syslog(LOG_ERR,"Symbolic link encountered in job %s - aborting",
193 if ((lbuf.st_dev != buf.st_dev) || (lbuf.st_ino != buf.st_ino) ||
194 (lbuf.st_uid != buf.st_uid) || (lbuf.st_gid != buf.st_gid) ||
195 (lbuf.st_size!=buf.st_size)) {
196 syslog(LOG_ERR,"Somebody changed files from under us for job %s - "
197 "aborting",filename);
200 if (buf.st_nlink > 1) {
201 syslog(LOG_ERR,"Someboy is trying to run a linked script for job %s",
205 if ((fflags = fcntl(fd_in, F_GETFD)) <0)
206 perr("error in fcntl");
208 fcntl(fd_in, F_SETFD, fflags & ~FD_CLOEXEC);
210 snprintf(fmt, sizeof(fmt),
211 "#!/bin/sh\n# atrun uid=%%ld gid=%%ld\n# mail %%%ds %%d",
213 if (fscanf(stream, fmt, &nuid, &ngid, mailbuf, &send_mail) != 4) {
214 syslog(LOG_ERR,"File %s is in wrong format - aborting", filename);
217 if (mailbuf[0] == '-') {
218 syslog(LOG_ERR,"illegal mail name %s in %s",mailbuf,filename);
223 syslog(LOG_ERR,"Job %s - userid %ld does not match file uid %lu",
224 filename, nuid, (unsigned long)uid);
228 syslog(LOG_ERR,"Job %s - groupid %ld does not match file gid %lu",
229 filename, ngid, (unsigned long)gid);
233 if (chdir(ATSPOOL_DIR) < 0)
234 perr("cannot chdir to " ATSPOOL_DIR);
236 /* Create a file to hold the output of the job we are about to run.
237 * Write the mail header.
239 if((fd_out=open(filename,
240 O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR)) < 0)
241 perr("cannot create output file");
243 write_string(fd_out, "Subject: Output from your job ");
244 write_string(fd_out, filename);
245 write_string(fd_out, "\n\n");
250 close(STDOUT_FILENO);
251 close(STDERR_FILENO);
255 perr("error in fork");
262 /* Set up things for the child; we want standard input from the input file,
263 * and standard output and error sent to our output file.
266 if (lseek(fd_in, (off_t) 0, SEEK_SET) < 0)
267 perr("error in lseek");
269 if (dup(fd_in) != STDIN_FILENO)
270 perr("error in I/O redirection");
272 if (dup(fd_out) != STDOUT_FILENO)
273 perr("error in I/O redirection");
275 if (dup(fd_out) != STDERR_FILENO)
276 perr("error in I/O redirection");
280 if (chdir(ATJOB_DIR) < 0)
281 perr("cannot chdir to " ATJOB_DIR);
287 nice(tolower(queue) - 'a');
289 if (initgroups(pentry->pw_name,pentry->pw_gid))
290 perr("cannot delete saved userids");
292 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
293 perr("cannot change group");
295 if (setlogin(pentry->pw_name))
296 perr("cannot set login name");
298 if (setuid(uid) < 0 || seteuid(uid) < 0)
299 perr("cannot set user id");
301 if (chdir(pentry->pw_dir))
304 if(execle("/bin/sh","sh",(char *) NULL, nenvp) != 0)
305 perr("exec failed for /bin/sh");
309 /* We're the parent. Let's wait.
313 waitpid(pid, (int *) NULL, 0);
315 /* Send mail. Unlink the output file first, so it is deleted after
318 stat(filename, &buf);
319 if (open(filename, O_RDONLY) != STDIN_FILENO)
320 perr("open of jobfile failed");
323 if ((buf.st_size != size) || send_mail)
327 if (initgroups(pentry->pw_name,pentry->pw_gid))
328 perr("cannot delete saved userids");
330 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
331 perr("cannot change group");
333 if (setlogin(pentry->pw_name))
334 perr("cannot set login name");
336 if (setuid(uid) < 0 || seteuid(uid) < 0)
337 perr("cannot set user id");
339 if (chdir(pentry->pw_dir))
343 execl(_PATH_SENDMAIL, "sendmail", "-F", "Atrun Service",
345 mailname, (char *) NULL);
347 execl(MAIL_CMD, MAIL_CMD, mailname, (char *) NULL);
349 perr("exec failed for mail command");
356 /* Global functions */
358 /* Needed in gloadavg.c */
367 syslog(LOG_ERR, "%s: %m", a);
373 main(int argc, char *argv[])
375 /* Browse through ATJOB_DIR, checking all the jobfiles wether they should
376 * be executed and or deleted. The queue is coded into the first byte of
377 * the job filename, the date (in minutes since Eon) as a hex number in the
378 * following eight bytes, followed by a dot and a serial number. A file
379 * which has not been executed yet is denoted by its execute - bit set.
380 * For those files which are to be executed, run_file() is called, which forks
381 * off a child which takes care of I/O redirection, forks off another child
382 * for execution and yet another one, optionally, for sending mail.
383 * Files which already have run are removed during the next invocation.
386 struct dirent *dirent;
391 time_t now, run_time;
392 char batch_name[] = "Z2345678901234";
397 double load_avg = LOADAVG_MX;
399 /* We don't need root privileges all the time; running under uid and gid daemon
403 RELINQUISH_PRIVS_ROOT(DAEMON_UID, DAEMON_GID)
405 openlog("atrun", LOG_PID, LOG_CRON);
408 while((c=getopt(argc, argv, "dl:"))!= -1)
413 if (sscanf(optarg, "%lf", &load_avg) != 1)
414 perr("garbled option -l");
416 load_avg = LOADAVG_MX;
429 if (chdir(ATJOB_DIR) != 0)
430 perr("cannot change to " ATJOB_DIR);
432 /* Main loop. Open spool directory for reading and look over all the
433 * files in there. If the filename indicates that the job should be run
434 * and the x bit is set, fork off a child which sets its user and group
435 * id to that of the files and exec a /bin/sh which executes the shell
436 * script. Unlink older files if they should no longer be run. For
437 * deletion, their r bit has to be turned on.
439 * Also, pick the oldest batch job to run, at most one per invocation of
442 if ((spool = opendir(".")) == NULL)
443 perr("cannot read " ATJOB_DIR);
447 batch_uid = (uid_t) -1;
448 batch_gid = (gid_t) -1;
450 while ((dirent = readdir(spool)) != NULL) {
451 if (stat(dirent->d_name,&buf) != 0)
452 perr("cannot stat in " ATJOB_DIR);
454 /* We don't want directories
456 if (!S_ISREG(buf.st_mode))
459 if (sscanf(dirent->d_name,"%c%5lx%8lx",&queue,&jobno,&ctm) != 3)
462 run_time = (time_t) ctm*60;
464 if ((S_IXUSR & buf.st_mode) && (run_time <=now)) {
465 if (isupper(queue) && (strcmp(batch_name,dirent->d_name) > 0)) {
467 strncpy(batch_name, dirent->d_name, sizeof(batch_name));
468 batch_uid = buf.st_uid;
469 batch_gid = buf.st_gid;
472 /* The file is executable and old enough
475 run_file(dirent->d_name, buf.st_uid, buf.st_gid);
477 /* Delete older files
479 if ((run_time < now) && !(S_IXUSR & buf.st_mode) && (S_IRUSR & buf.st_mode))
480 unlink(dirent->d_name);
482 /* run the single batch file, if any
484 if (run_batch && (gloadavg() < load_avg))
485 run_file(batch_name, batch_uid, batch_gid);
495 fprintf(stderr, "usage: atrun [-l load_avg] [-d]\n");
497 syslog(LOG_ERR, "usage: atrun [-l load_avg] [-d]");