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 1.5 2004/09/20 19:32:19 joerg Exp $
31 #include <sys/fcntl.h>
32 #include <sys/types.h>
35 #include <sys/param.h>
52 #if (MAXLOGNAME-1) > UT_NAMESIZE
53 #define LOGNAMESIZE UT_NAMESIZE
55 #define LOGNAMESIZE (MAXLOGNAME-1)
66 #define ATJOB_DIR "/usr/spool/atjobs/"
70 #define ATSPOOL_DIR "/usr/spool/atspool/"
74 #define LOADAVG_MX 1.5
77 uid_t real_uid, effective_uid;
78 gid_t real_gid, effective_gid;
80 /* File scope variables */
84 void perr(const char *a);
85 static void usage(void);
89 write_string(int fd, const char* a)
91 return write(fd, a, strlen(a));
102 kill(getpid(),SIGSTOP);
110 run_file(const char *filename, uid_t uid, gid_t gid)
112 /* Run a file by by spawning off a process which redirects I/O,
113 * spawns a subshell, then waits for it to complete and sends
119 char mailbuf[LOGNAMESIZE + 1], fmt[49];
120 char *mailname = NULL;
123 struct stat buf, lbuf;
125 struct passwd *pentry;
133 if (chmod(filename, S_IRUSR) != 0)
135 perr("cannot change file permissions");
147 /* Let's see who we mail to. Hopefully, we can read it from
148 * the command file; if not, send it to the owner, or, failing that,
152 pentry = getpwuid(uid);
155 syslog(LOG_ERR,"Userid %lu not found - aborting job %s",
156 (unsigned long) uid, filename);
161 stream=fopen(filename, "r");
166 if (pentry->pw_expire && time(NULL) >= pentry->pw_expire)
168 syslog(LOG_ERR, "Userid %lu is expired - aborting job %s",
169 (unsigned long) uid, filename);
175 perr("cannot open input file");
177 if ((fd_in = dup(fileno(stream))) <0)
178 perr("error duplicating input file descriptor");
180 if (fstat(fd_in, &buf) == -1)
181 perr("error in fstat of input file descriptor");
183 if (lstat(filename, &lbuf) == -1)
184 perr("error in fstat of input file");
186 if (S_ISLNK(lbuf.st_mode)) {
187 syslog(LOG_ERR,"Symbolic link encountered in job %s - aborting",
191 if ((lbuf.st_dev != buf.st_dev) || (lbuf.st_ino != buf.st_ino) ||
192 (lbuf.st_uid != buf.st_uid) || (lbuf.st_gid != buf.st_gid) ||
193 (lbuf.st_size!=buf.st_size)) {
194 syslog(LOG_ERR,"Somebody changed files from under us for job %s - "
195 "aborting",filename);
198 if (buf.st_nlink > 1) {
199 syslog(LOG_ERR,"Someboy is trying to run a linked script for job %s",
203 if ((fflags = fcntl(fd_in, F_GETFD)) <0)
204 perr("error in fcntl");
206 fcntl(fd_in, F_SETFD, fflags & ~FD_CLOEXEC);
208 snprintf(fmt, sizeof(fmt),
209 "#!/bin/sh\n# atrun uid=%%ld gid=%%ld\n# mail %%%ds %%d",
211 if (fscanf(stream, fmt, &nuid, &ngid, mailbuf, &send_mail) != 4) {
212 syslog(LOG_ERR,"File %s is in wrong format - aborting", filename);
215 if (mailbuf[0] == '-') {
216 syslog(LOG_ERR,"illegal mail name %s in %s",mailbuf,filename);
221 syslog(LOG_ERR,"Job %s - userid %u does not match file uid %lu",
222 filename, nuid, (unsigned long)uid);
226 syslog(LOG_ERR,"Job %s - groupid %u does not match file gid %lu",
227 filename, ngid, (unsigned long)gid);
231 if (chdir(ATSPOOL_DIR) < 0)
232 perr("cannot chdir to " ATSPOOL_DIR);
234 /* Create a file to hold the output of the job we are about to run.
235 * Write the mail header.
237 if((fd_out=open(filename,
238 O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR)) < 0)
239 perr("cannot create output file");
241 write_string(fd_out, "Subject: Output from your job ");
242 write_string(fd_out, filename);
243 write_string(fd_out, "\n\n");
248 close(STDOUT_FILENO);
249 close(STDERR_FILENO);
253 perr("error in fork");
260 /* Set up things for the child; we want standard input from the input file,
261 * and standard output and error sent to our output file.
264 if (lseek(fd_in, (off_t) 0, SEEK_SET) < 0)
265 perr("error in lseek");
267 if (dup(fd_in) != STDIN_FILENO)
268 perr("error in I/O redirection");
270 if (dup(fd_out) != STDOUT_FILENO)
271 perr("error in I/O redirection");
273 if (dup(fd_out) != STDERR_FILENO)
274 perr("error in I/O redirection");
278 if (chdir(ATJOB_DIR) < 0)
279 perr("cannot chdir to " ATJOB_DIR);
285 nice(tolower(queue) - 'a');
287 if (initgroups(pentry->pw_name,pentry->pw_gid))
288 perr("cannot delete saved userids");
290 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
291 perr("cannot change group");
293 if (setlogin(pentry->pw_name))
294 perr("cannot set login name");
296 if (setuid(uid) < 0 || seteuid(uid) < 0)
297 perr("cannot set user id");
299 if (chdir(pentry->pw_dir))
302 if(execle("/bin/sh","sh",(char *) NULL, nenvp) != 0)
303 perr("exec failed for /bin/sh");
307 /* We're the parent. Let's wait.
311 waitpid(pid, (int *) NULL, 0);
313 /* Send mail. Unlink the output file first, so it is deleted after
316 stat(filename, &buf);
317 if (open(filename, O_RDONLY) != STDIN_FILENO)
318 perr("open of jobfile failed");
321 if ((buf.st_size != size) || send_mail)
325 if (initgroups(pentry->pw_name,pentry->pw_gid))
326 perr("cannot delete saved userids");
328 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
329 perr("cannot change group");
331 if (setlogin(pentry->pw_name))
332 perr("cannot set login name");
334 if (setuid(uid) < 0 || seteuid(uid) < 0)
335 perr("cannot set user id");
337 if (chdir(pentry->pw_dir))
340 execl(_PATH_SENDMAIL, "sendmail", "-F", "Atrun Service",
342 mailname, (char *) NULL);
343 perr("exec failed for mail command");
350 /* Global functions */
352 /* Needed in gloadavg.c */
361 syslog(LOG_ERR, "%s: %m", a);
367 main(int argc, char *argv[])
369 /* Browse through ATJOB_DIR, checking all the jobfiles wether they should
370 * be executed and or deleted. The queue is coded into the first byte of
371 * the job filename, the date (in minutes since Eon) as a hex number in the
372 * following eight bytes, followed by a dot and a serial number. A file
373 * which has not been executed yet is denoted by its execute - bit set.
374 * For those files which are to be executed, run_file() is called, which forks
375 * off a child which takes care of I/O redirection, forks off another child
376 * for execution and yet another one, optionally, for sending mail.
377 * Files which already have run are removed during the next invocation.
380 struct dirent *dirent;
385 time_t now, run_time;
386 char batch_name[] = "Z2345678901234";
391 double load_avg = LOADAVG_MX;
393 /* We don't need root privileges all the time; running under uid and gid daemon
397 RELINQUISH_PRIVS_ROOT(DAEMON_UID, DAEMON_GID)
399 openlog("atrun", LOG_PID, LOG_CRON);
402 while((c=getopt(argc, argv, "dl:"))!= -1)
407 if (sscanf(optarg, "%lf", &load_avg) != 1)
408 perr("garbled option -l");
410 load_avg = LOADAVG_MX;
423 if (chdir(ATJOB_DIR) != 0)
424 perr("cannot change to " ATJOB_DIR);
426 /* Main loop. Open spool directory for reading and look over all the
427 * files in there. If the filename indicates that the job should be run
428 * and the x bit is set, fork off a child which sets its user and group
429 * id to that of the files and exec a /bin/sh which executes the shell
430 * script. Unlink older files if they should no longer be run. For
431 * deletion, their r bit has to be turned on.
433 * Also, pick the oldest batch job to run, at most one per invocation of
436 if ((spool = opendir(".")) == NULL)
437 perr("cannot read " ATJOB_DIR);
441 batch_uid = (uid_t) -1;
442 batch_gid = (gid_t) -1;
444 while ((dirent = readdir(spool)) != NULL) {
445 if (stat(dirent->d_name,&buf) != 0)
446 perr("cannot stat in " ATJOB_DIR);
448 /* We don't want directories
450 if (!S_ISREG(buf.st_mode))
453 if (sscanf(dirent->d_name,"%c%5lx%8lx",&queue,&jobno,&ctm) != 3)
456 run_time = (time_t) ctm*60;
458 if ((S_IXUSR & buf.st_mode) && (run_time <=now)) {
459 if (isupper(queue) && (strcmp(batch_name,dirent->d_name) > 0)) {
461 strncpy(batch_name, dirent->d_name, sizeof(batch_name));
462 batch_uid = buf.st_uid;
463 batch_gid = buf.st_gid;
466 /* The file is executable and old enough
469 run_file(dirent->d_name, buf.st_uid, buf.st_gid);
471 /* Delete older files
473 if ((run_time < now) && !(S_IXUSR & buf.st_mode) && (S_IRUSR & buf.st_mode))
474 unlink(dirent->d_name);
476 /* run the single batch file, if any
478 if (run_batch && (gloadavg() < load_avg))
479 run_file(batch_name, batch_uid, batch_gid);
489 fprintf(stderr, "usage: atrun [-l load_avg] [-d]\n");
491 syslog(LOG_ERR, "usage: atrun [-l load_avg] [-d]");