1/*
2 * atrun.c - run jobs queued by at; run with root privileges.
3 * Copyright (C) 1993, 1994 Thomas Koenig
4 *
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.
13 *
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.
24 */
25
26#ifndef lint
27static const char rcsid[] =
28 "$FreeBSD: head/libexec/atrun/atrun.c 131990 2004-07-11 17:37:33Z stefanf $";
29#endif /* not lint */
30
31/* System Headers */
32
33#include <sys/fcntl.h>
34#include <sys/types.h>
35#include <sys/stat.h>
36#include <sys/wait.h>
37#include <sys/param.h>
38#include <ctype.h>
39#include <dirent.h>
40#include <err.h>
41#include <grp.h>
42#include <pwd.h>
43#include <signal.h>
44#include <stddef.h>
45#include <stdio.h>
46#include <stdlib.h>
47#include <string.h>
48#include <syslog.h>
49#include <time.h>
50#include <unistd.h>
51#include <utmp.h>
52#ifdef __FreeBSD__
53#include <paths.h>
54#else
55#include <getopt.h>
56#endif
57
58#if (MAXLOGNAME-1) > UT_NAMESIZE
59#define LOGNAMESIZE UT_NAMESIZE
60#else
61#define LOGNAMESIZE (MAXLOGNAME-1)
62#endif
63
64/* Local headers */
65
66#include "gloadavg.h"
67#define MAIN
68#include "privs.h"
69
70/* Macros */
71
72#ifndef ATJOB_DIR
73#define ATJOB_DIR "/usr/spool/atjobs/"
74#endif
75
76#ifndef ATSPOOL_DIR
77#define ATSPOOL_DIR "/usr/spool/atspool/"
78#endif
79
80#ifndef LOADAVG_MX
81#define LOADAVG_MX 1.5
82#endif
83
84/* File scope variables */
85
86static int debug = 0;
87
88void perr(const char *a);
89static void usage(void);
90
91/* Local functions */
92static int
93write_string(int fd, const char* a)
94{
95 return write(fd, a, strlen(a));
96}
97
98#undef DEBUG_FORK
99#ifdef DEBUG_FORK
100static pid_t
101myfork(void)
102{
103 pid_t res;
104 res = fork();
105 if (res == 0)
106 kill(getpid(),SIGSTOP);
107 return res;
108}
109
110#define fork myfork
111#endif
112
113static void
114run_file(const char *filename, uid_t uid, gid_t gid)
115{
116/* Run a file by spawning off a process which redirects I/O,
117 * spawns a subshell, then waits for it to complete and sends
118 * mail to the user.
119 */
120 pid_t pid;
121 int fd_out, fd_in;
122 int queue;
123 char mailbuf[LOGNAMESIZE + 1], fmt[49];
124 char *mailname = NULL;
125 FILE *stream;
126 int send_mail = 0;
127 struct stat buf, lbuf;
128 off_t size;
129 struct passwd *pentry;
130 int fflags;
131 long nuid;
132 long ngid;
133
134
135 PRIV_START
136
137 if (chmod(filename, S_IRUSR) != 0)
138 {
139 perr("cannot change file permissions");
140 }
141
142 PRIV_END
143
144 pid = fork();
145 if (pid == -1)
146 perr("cannot fork");
147
148 else if (pid != 0)
149 return;
150
151 /* Let's see who we mail to. Hopefully, we can read it from
152 * the command file; if not, send it to the owner, or, failing that,
153 * to root.
154 */
155
156 pentry = getpwuid(uid);
157 if (pentry == NULL)
158 {
159 syslog(LOG_ERR,"Userid %lu not found - aborting job %s",
160 (unsigned long) uid, filename);
161 exit(EXIT_FAILURE);
162 }
163 PRIV_START
164
165 stream=fopen(filename, "r");
166
167 PRIV_END
168
169#ifdef __FreeBSD__
170 if (pentry->pw_expire && time(NULL) >= pentry->pw_expire)
171 {
172 syslog(LOG_ERR, "Userid %lu is expired - aborting job %s",
173 (unsigned long) uid, filename);
174 exit(EXIT_FAILURE);
175 }
176#endif
177
178 if (stream == NULL)
179 perr("cannot open input file");
180
181 if ((fd_in = dup(fileno(stream))) <0)
182 perr("error duplicating input file descriptor");
183
184 if (fstat(fd_in, &buf) == -1)
185 perr("error in fstat of input file descriptor");
186
187 if (lstat(filename, &lbuf) == -1)
188 perr("error in fstat of input file");
189
190 if (S_ISLNK(lbuf.st_mode)) {
191 syslog(LOG_ERR,"Symbolic link encountered in job %s - aborting",
192 filename);
193 exit(EXIT_FAILURE);
194 }
195 if ((lbuf.st_dev != buf.st_dev) || (lbuf.st_ino != buf.st_ino) ||
196 (lbuf.st_uid != buf.st_uid) || (lbuf.st_gid != buf.st_gid) ||
197 (lbuf.st_size!=buf.st_size)) {
198 syslog(LOG_ERR,"Somebody changed files from under us for job %s - "
199 "aborting",filename);
200 exit(EXIT_FAILURE);
201 }
202 if (buf.st_nlink > 1) {
203 syslog(LOG_ERR,"Someboy is trying to run a linked script for job %s",
204 filename);
205 exit(EXIT_FAILURE);
206 }
207 if ((fflags = fcntl(fd_in, F_GETFD)) <0)
208 perr("error in fcntl");
209
210 fcntl(fd_in, F_SETFD, fflags & ~FD_CLOEXEC);
211
212 snprintf(fmt, sizeof(fmt),
213 "#!/bin/sh\n# atrun uid=%%ld gid=%%ld\n# mail %%%ds %%d",
214 LOGNAMESIZE);
215 if (fscanf(stream, fmt, &nuid, &ngid, mailbuf, &send_mail) != 4) {
216 syslog(LOG_ERR,"File %s is in wrong format - aborting", filename);
217 exit(EXIT_FAILURE);
218 }
219 if (mailbuf[0] == '-') {
220 syslog(LOG_ERR,"illegal mail name %s in %s",mailbuf,filename);
221 exit(EXIT_FAILURE);
222 }
223 mailname = mailbuf;
224 if (nuid != uid) {
225 syslog(LOG_ERR,"Job %s - userid %ld does not match file uid %lu",
226 filename, nuid, (unsigned long)uid);
227 exit(EXIT_FAILURE);
228 }
229 if (ngid != gid) {
230 syslog(LOG_ERR,"Job %s - groupid %ld does not match file gid %lu",
231 filename, ngid, (unsigned long)gid);
232 exit(EXIT_FAILURE);
233 }
234 fclose(stream);
235 if (chdir(ATSPOOL_DIR) < 0)
236 perr("cannot chdir to " ATSPOOL_DIR);
237
238 /* Create a file to hold the output of the job we are about to run.
239 * Write the mail header.
240 */
241 if((fd_out=open(filename,
242 O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR)) < 0)
243 perr("cannot create output file");
244
245 write_string(fd_out, "Subject: Output from your job ");
246 write_string(fd_out, filename);
247 write_string(fd_out, "\n\n");
248 fstat(fd_out, &buf);
249 size = buf.st_size;
250
251 close(STDIN_FILENO);
252 close(STDOUT_FILENO);
253 close(STDERR_FILENO);
254
255 pid = fork();
256 if (pid < 0)
257 perr("error in fork");
258
259 else if (pid == 0)
260 {
261 char *nul = NULL;
262 char **nenvp = &nul;
263
264 /* Set up things for the child; we want standard input from the input file,
265 * and standard output and error sent to our output file.
266 */
267
268 if (lseek(fd_in, (off_t) 0, SEEK_SET) < 0)
269 perr("error in lseek");
270
271 if (dup(fd_in) != STDIN_FILENO)
272 perr("error in I/O redirection");
273
274 if (dup(fd_out) != STDOUT_FILENO)
275 perr("error in I/O redirection");
276
277 if (dup(fd_out) != STDERR_FILENO)
278 perr("error in I/O redirection");
279
280 close(fd_in);
281 close(fd_out);
282 if (chdir(ATJOB_DIR) < 0)
283 perr("cannot chdir to " ATJOB_DIR);
284
285 queue = *filename;
286
287 PRIV_START
288
289 nice(tolower(queue) - 'a');
290
291 if (initgroups(pentry->pw_name,pentry->pw_gid))
292 perr("cannot delete saved userids");
293
294 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
295 perr("cannot change group");
296
297 if (setlogin(pentry->pw_name))
298 perr("cannot set login name");
299
300 if (setuid(uid) < 0 || seteuid(uid) < 0)
301 perr("cannot set user id");
302
303 if (chdir(pentry->pw_dir))
304 chdir("/");
305
306 if(execle("/bin/sh","sh",(char *) NULL, nenvp) != 0)
307 perr("exec failed for /bin/sh");
308
309 PRIV_END
310 }
311 /* We're the parent. Let's wait.
312 */
313 close(fd_in);
314 close(fd_out);
315 waitpid(pid, (int *) NULL, 0);
316
317 /* Send mail. Unlink the output file first, so it is deleted after
318 * the run.
319 */
320 stat(filename, &buf);
321 if (open(filename, O_RDONLY) != STDIN_FILENO)
322 perr("open of jobfile failed");
323
324 unlink(filename);
325 if ((buf.st_size != size) || send_mail)
326 {
327 PRIV_START
328
329 if (initgroups(pentry->pw_name,pentry->pw_gid))
330 perr("cannot delete saved userids");
331
332 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
333 perr("cannot change group");
334
335 if (setlogin(pentry->pw_name))
336 perr("cannot set login name");
337
338 if (setuid(uid) < 0 || seteuid(uid) < 0)
339 perr("cannot set user id");
340
341 if (chdir(pentry->pw_dir))
342 chdir("/");
343
344#ifdef __FreeBSD__
345 execl(_PATH_SENDMAIL, "sendmail", "-F", "Atrun Service",
346 "-odi", "-oem",
347 mailname, (char *) NULL);
348#else
349 execl(MAIL_CMD, MAIL_CMD, mailname, (char *) NULL);
350#endif
351 perr("exec failed for mail command");
352
353 PRIV_END
354 }
355 exit(EXIT_SUCCESS);
356}
357
358/* Global functions */
359
360/* Needed in gloadavg.c */
361void
362perr(const char *a)
363{
364 if (debug)
365 {
366 warn("%s", a);
367 }
368 else
369 syslog(LOG_ERR, "%s: %m", a);
370
371 exit(EXIT_FAILURE);
372}
373
374int
375main(int argc, char *argv[])
376{
377/* Browse through ATJOB_DIR, checking all the jobfiles wether they should
378 * be executed and or deleted. The queue is coded into the first byte of
379 * the job filename, the date (in minutes since Eon) as a hex number in the
380 * following eight bytes, followed by a dot and a serial number. A file
381 * which has not been executed yet is denoted by its execute - bit set.
382 * For those files which are to be executed, run_file() is called, which forks
383 * off a child which takes care of I/O redirection, forks off another child
384 * for execution and yet another one, optionally, for sending mail.
385 * Files which already have run are removed during the next invocation.
386 */
387 DIR *spool;
388 struct dirent *dirent;
389 struct stat buf;
390 unsigned long ctm;
391 unsigned long jobno;
392 char queue;
393 time_t now, run_time;
394 char batch_name[] = "Z2345678901234";
395 uid_t batch_uid;
396 gid_t batch_gid;
397 int c;
398 int run_batch;
399 double load_avg = LOADAVG_MX;
400
401/* We don't need root privileges all the time; running under uid and gid daemon
402 * is fine.
403 */
404
405 RELINQUISH_PRIVS_ROOT(DAEMON_UID, DAEMON_GID)
406
407 openlog("atrun", LOG_PID, LOG_CRON);
408
409 opterr = 0;
410 while((c=getopt(argc, argv, "dl:"))!= -1)
411 {
412 switch (c)
413 {
414 case 'l':
415 if (sscanf(optarg, "%lf", &load_avg) != 1)
416 perr("garbled option -l");
417 if (load_avg <= 0.)
418 load_avg = LOADAVG_MX;
419 break;
420
421 case 'd':
422 debug ++;
423 break;
424
425 case '?':
426 default:
427 usage();
428 }
429 }
430
431 if (chdir(ATJOB_DIR) != 0)
432 perr("cannot change to " ATJOB_DIR);
433
434 /* Main loop. Open spool directory for reading and look over all the
435 * files in there. If the filename indicates that the job should be run
436 * and the x bit is set, fork off a child which sets its user and group
437 * id to that of the files and exec a /bin/sh which executes the shell
438 * script. Unlink older files if they should no longer be run. For
439 * deletion, their r bit has to be turned on.
440 *
441 * Also, pick the oldest batch job to run, at most one per invocation of
442 * atrun.
443 */
444 if ((spool = opendir(".")) == NULL)
445 perr("cannot read " ATJOB_DIR);
446
447 now = time(NULL);
448 run_batch = 0;
449 batch_uid = (uid_t) -1;
450 batch_gid = (gid_t) -1;
451
452 while ((dirent = readdir(spool)) != NULL) {
453 if (stat(dirent->d_name,&buf) != 0)
454 perr("cannot stat in " ATJOB_DIR);
455
456 /* We don't want directories
457 */
458 if (!S_ISREG(buf.st_mode))
459 continue;
460
461 if (sscanf(dirent->d_name,"%c%5lx%8lx",&queue,&jobno,&ctm) != 3)
462 continue;
463
464 run_time = (time_t) ctm*60;
465
466 if ((S_IXUSR & buf.st_mode) && (run_time <=now)) {
467 if (isupper(queue) && (strcmp(batch_name,dirent->d_name) > 0)) {
468 run_batch = 1;
469 strncpy(batch_name, dirent->d_name, sizeof(batch_name));
470 batch_uid = buf.st_uid;
471 batch_gid = buf.st_gid;
472 }
473
474 /* The file is executable and old enough
475 */
476 if (islower(queue))
477 run_file(dirent->d_name, buf.st_uid, buf.st_gid);
478 }
479 /* Delete older files
480 */
481 if ((run_time < now) && !(S_IXUSR & buf.st_mode) && (S_IRUSR & buf.st_mode))
482 unlink(dirent->d_name);
483 }
484 /* run the single batch file, if any
485 */
486 if (run_batch && (gloadavg() < load_avg))
487 run_file(batch_name, batch_uid, batch_gid);
488
489 closelog();
490 exit(EXIT_SUCCESS);
491}
492
493static void
494usage(void)
495{
496 if (debug)
497 fprintf(stderr, "usage: atrun [-l load_avg] [-d]\n");
498 else
499 syslog(LOG_ERR, "usage: atrun [-l load_avg] [-d]");
500
501 exit(EXIT_FAILURE);
502}
2 * atrun.c - run jobs queued by at; run with root privileges.
3 * Copyright (C) 1993, 1994 Thomas Koenig
4 *
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.
13 *
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.
24 */
25
26#ifndef lint
27static const char rcsid[] =
28 "$FreeBSD: head/libexec/atrun/atrun.c 131990 2004-07-11 17:37:33Z stefanf $";
29#endif /* not lint */
30
31/* System Headers */
32
33#include <sys/fcntl.h>
34#include <sys/types.h>
35#include <sys/stat.h>
36#include <sys/wait.h>
37#include <sys/param.h>
38#include <ctype.h>
39#include <dirent.h>
40#include <err.h>
41#include <grp.h>
42#include <pwd.h>
43#include <signal.h>
44#include <stddef.h>
45#include <stdio.h>
46#include <stdlib.h>
47#include <string.h>
48#include <syslog.h>
49#include <time.h>
50#include <unistd.h>
51#include <utmp.h>
52#ifdef __FreeBSD__
53#include <paths.h>
54#else
55#include <getopt.h>
56#endif
57
58#if (MAXLOGNAME-1) > UT_NAMESIZE
59#define LOGNAMESIZE UT_NAMESIZE
60#else
61#define LOGNAMESIZE (MAXLOGNAME-1)
62#endif
63
64/* Local headers */
65
66#include "gloadavg.h"
67#define MAIN
68#include "privs.h"
69
70/* Macros */
71
72#ifndef ATJOB_DIR
73#define ATJOB_DIR "/usr/spool/atjobs/"
74#endif
75
76#ifndef ATSPOOL_DIR
77#define ATSPOOL_DIR "/usr/spool/atspool/"
78#endif
79
80#ifndef LOADAVG_MX
81#define LOADAVG_MX 1.5
82#endif
83
84/* File scope variables */
85
86static int debug = 0;
87
88void perr(const char *a);
89static void usage(void);
90
91/* Local functions */
92static int
93write_string(int fd, const char* a)
94{
95 return write(fd, a, strlen(a));
96}
97
98#undef DEBUG_FORK
99#ifdef DEBUG_FORK
100static pid_t
101myfork(void)
102{
103 pid_t res;
104 res = fork();
105 if (res == 0)
106 kill(getpid(),SIGSTOP);
107 return res;
108}
109
110#define fork myfork
111#endif
112
113static void
114run_file(const char *filename, uid_t uid, gid_t gid)
115{
116/* Run a file by spawning off a process which redirects I/O,
117 * spawns a subshell, then waits for it to complete and sends
118 * mail to the user.
119 */
120 pid_t pid;
121 int fd_out, fd_in;
122 int queue;
123 char mailbuf[LOGNAMESIZE + 1], fmt[49];
124 char *mailname = NULL;
125 FILE *stream;
126 int send_mail = 0;
127 struct stat buf, lbuf;
128 off_t size;
129 struct passwd *pentry;
130 int fflags;
131 long nuid;
132 long ngid;
133
134
135 PRIV_START
136
137 if (chmod(filename, S_IRUSR) != 0)
138 {
139 perr("cannot change file permissions");
140 }
141
142 PRIV_END
143
144 pid = fork();
145 if (pid == -1)
146 perr("cannot fork");
147
148 else if (pid != 0)
149 return;
150
151 /* Let's see who we mail to. Hopefully, we can read it from
152 * the command file; if not, send it to the owner, or, failing that,
153 * to root.
154 */
155
156 pentry = getpwuid(uid);
157 if (pentry == NULL)
158 {
159 syslog(LOG_ERR,"Userid %lu not found - aborting job %s",
160 (unsigned long) uid, filename);
161 exit(EXIT_FAILURE);
162 }
163 PRIV_START
164
165 stream=fopen(filename, "r");
166
167 PRIV_END
168
169#ifdef __FreeBSD__
170 if (pentry->pw_expire && time(NULL) >= pentry->pw_expire)
171 {
172 syslog(LOG_ERR, "Userid %lu is expired - aborting job %s",
173 (unsigned long) uid, filename);
174 exit(EXIT_FAILURE);
175 }
176#endif
177
178 if (stream == NULL)
179 perr("cannot open input file");
180
181 if ((fd_in = dup(fileno(stream))) <0)
182 perr("error duplicating input file descriptor");
183
184 if (fstat(fd_in, &buf) == -1)
185 perr("error in fstat of input file descriptor");
186
187 if (lstat(filename, &lbuf) == -1)
188 perr("error in fstat of input file");
189
190 if (S_ISLNK(lbuf.st_mode)) {
191 syslog(LOG_ERR,"Symbolic link encountered in job %s - aborting",
192 filename);
193 exit(EXIT_FAILURE);
194 }
195 if ((lbuf.st_dev != buf.st_dev) || (lbuf.st_ino != buf.st_ino) ||
196 (lbuf.st_uid != buf.st_uid) || (lbuf.st_gid != buf.st_gid) ||
197 (lbuf.st_size!=buf.st_size)) {
198 syslog(LOG_ERR,"Somebody changed files from under us for job %s - "
199 "aborting",filename);
200 exit(EXIT_FAILURE);
201 }
202 if (buf.st_nlink > 1) {
203 syslog(LOG_ERR,"Someboy is trying to run a linked script for job %s",
204 filename);
205 exit(EXIT_FAILURE);
206 }
207 if ((fflags = fcntl(fd_in, F_GETFD)) <0)
208 perr("error in fcntl");
209
210 fcntl(fd_in, F_SETFD, fflags & ~FD_CLOEXEC);
211
212 snprintf(fmt, sizeof(fmt),
213 "#!/bin/sh\n# atrun uid=%%ld gid=%%ld\n# mail %%%ds %%d",
214 LOGNAMESIZE);
215 if (fscanf(stream, fmt, &nuid, &ngid, mailbuf, &send_mail) != 4) {
216 syslog(LOG_ERR,"File %s is in wrong format - aborting", filename);
217 exit(EXIT_FAILURE);
218 }
219 if (mailbuf[0] == '-') {
220 syslog(LOG_ERR,"illegal mail name %s in %s",mailbuf,filename);
221 exit(EXIT_FAILURE);
222 }
223 mailname = mailbuf;
224 if (nuid != uid) {
225 syslog(LOG_ERR,"Job %s - userid %ld does not match file uid %lu",
226 filename, nuid, (unsigned long)uid);
227 exit(EXIT_FAILURE);
228 }
229 if (ngid != gid) {
230 syslog(LOG_ERR,"Job %s - groupid %ld does not match file gid %lu",
231 filename, ngid, (unsigned long)gid);
232 exit(EXIT_FAILURE);
233 }
234 fclose(stream);
235 if (chdir(ATSPOOL_DIR) < 0)
236 perr("cannot chdir to " ATSPOOL_DIR);
237
238 /* Create a file to hold the output of the job we are about to run.
239 * Write the mail header.
240 */
241 if((fd_out=open(filename,
242 O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR)) < 0)
243 perr("cannot create output file");
244
245 write_string(fd_out, "Subject: Output from your job ");
246 write_string(fd_out, filename);
247 write_string(fd_out, "\n\n");
248 fstat(fd_out, &buf);
249 size = buf.st_size;
250
251 close(STDIN_FILENO);
252 close(STDOUT_FILENO);
253 close(STDERR_FILENO);
254
255 pid = fork();
256 if (pid < 0)
257 perr("error in fork");
258
259 else if (pid == 0)
260 {
261 char *nul = NULL;
262 char **nenvp = &nul;
263
264 /* Set up things for the child; we want standard input from the input file,
265 * and standard output and error sent to our output file.
266 */
267
268 if (lseek(fd_in, (off_t) 0, SEEK_SET) < 0)
269 perr("error in lseek");
270
271 if (dup(fd_in) != STDIN_FILENO)
272 perr("error in I/O redirection");
273
274 if (dup(fd_out) != STDOUT_FILENO)
275 perr("error in I/O redirection");
276
277 if (dup(fd_out) != STDERR_FILENO)
278 perr("error in I/O redirection");
279
280 close(fd_in);
281 close(fd_out);
282 if (chdir(ATJOB_DIR) < 0)
283 perr("cannot chdir to " ATJOB_DIR);
284
285 queue = *filename;
286
287 PRIV_START
288
289 nice(tolower(queue) - 'a');
290
291 if (initgroups(pentry->pw_name,pentry->pw_gid))
292 perr("cannot delete saved userids");
293
294 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
295 perr("cannot change group");
296
297 if (setlogin(pentry->pw_name))
298 perr("cannot set login name");
299
300 if (setuid(uid) < 0 || seteuid(uid) < 0)
301 perr("cannot set user id");
302
303 if (chdir(pentry->pw_dir))
304 chdir("/");
305
306 if(execle("/bin/sh","sh",(char *) NULL, nenvp) != 0)
307 perr("exec failed for /bin/sh");
308
309 PRIV_END
310 }
311 /* We're the parent. Let's wait.
312 */
313 close(fd_in);
314 close(fd_out);
315 waitpid(pid, (int *) NULL, 0);
316
317 /* Send mail. Unlink the output file first, so it is deleted after
318 * the run.
319 */
320 stat(filename, &buf);
321 if (open(filename, O_RDONLY) != STDIN_FILENO)
322 perr("open of jobfile failed");
323
324 unlink(filename);
325 if ((buf.st_size != size) || send_mail)
326 {
327 PRIV_START
328
329 if (initgroups(pentry->pw_name,pentry->pw_gid))
330 perr("cannot delete saved userids");
331
332 if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0)
333 perr("cannot change group");
334
335 if (setlogin(pentry->pw_name))
336 perr("cannot set login name");
337
338 if (setuid(uid) < 0 || seteuid(uid) < 0)
339 perr("cannot set user id");
340
341 if (chdir(pentry->pw_dir))
342 chdir("/");
343
344#ifdef __FreeBSD__
345 execl(_PATH_SENDMAIL, "sendmail", "-F", "Atrun Service",
346 "-odi", "-oem",
347 mailname, (char *) NULL);
348#else
349 execl(MAIL_CMD, MAIL_CMD, mailname, (char *) NULL);
350#endif
351 perr("exec failed for mail command");
352
353 PRIV_END
354 }
355 exit(EXIT_SUCCESS);
356}
357
358/* Global functions */
359
360/* Needed in gloadavg.c */
361void
362perr(const char *a)
363{
364 if (debug)
365 {
366 warn("%s", a);
367 }
368 else
369 syslog(LOG_ERR, "%s: %m", a);
370
371 exit(EXIT_FAILURE);
372}
373
374int
375main(int argc, char *argv[])
376{
377/* Browse through ATJOB_DIR, checking all the jobfiles wether they should
378 * be executed and or deleted. The queue is coded into the first byte of
379 * the job filename, the date (in minutes since Eon) as a hex number in the
380 * following eight bytes, followed by a dot and a serial number. A file
381 * which has not been executed yet is denoted by its execute - bit set.
382 * For those files which are to be executed, run_file() is called, which forks
383 * off a child which takes care of I/O redirection, forks off another child
384 * for execution and yet another one, optionally, for sending mail.
385 * Files which already have run are removed during the next invocation.
386 */
387 DIR *spool;
388 struct dirent *dirent;
389 struct stat buf;
390 unsigned long ctm;
391 unsigned long jobno;
392 char queue;
393 time_t now, run_time;
394 char batch_name[] = "Z2345678901234";
395 uid_t batch_uid;
396 gid_t batch_gid;
397 int c;
398 int run_batch;
399 double load_avg = LOADAVG_MX;
400
401/* We don't need root privileges all the time; running under uid and gid daemon
402 * is fine.
403 */
404
405 RELINQUISH_PRIVS_ROOT(DAEMON_UID, DAEMON_GID)
406
407 openlog("atrun", LOG_PID, LOG_CRON);
408
409 opterr = 0;
410 while((c=getopt(argc, argv, "dl:"))!= -1)
411 {
412 switch (c)
413 {
414 case 'l':
415 if (sscanf(optarg, "%lf", &load_avg) != 1)
416 perr("garbled option -l");
417 if (load_avg <= 0.)
418 load_avg = LOADAVG_MX;
419 break;
420
421 case 'd':
422 debug ++;
423 break;
424
425 case '?':
426 default:
427 usage();
428 }
429 }
430
431 if (chdir(ATJOB_DIR) != 0)
432 perr("cannot change to " ATJOB_DIR);
433
434 /* Main loop. Open spool directory for reading and look over all the
435 * files in there. If the filename indicates that the job should be run
436 * and the x bit is set, fork off a child which sets its user and group
437 * id to that of the files and exec a /bin/sh which executes the shell
438 * script. Unlink older files if they should no longer be run. For
439 * deletion, their r bit has to be turned on.
440 *
441 * Also, pick the oldest batch job to run, at most one per invocation of
442 * atrun.
443 */
444 if ((spool = opendir(".")) == NULL)
445 perr("cannot read " ATJOB_DIR);
446
447 now = time(NULL);
448 run_batch = 0;
449 batch_uid = (uid_t) -1;
450 batch_gid = (gid_t) -1;
451
452 while ((dirent = readdir(spool)) != NULL) {
453 if (stat(dirent->d_name,&buf) != 0)
454 perr("cannot stat in " ATJOB_DIR);
455
456 /* We don't want directories
457 */
458 if (!S_ISREG(buf.st_mode))
459 continue;
460
461 if (sscanf(dirent->d_name,"%c%5lx%8lx",&queue,&jobno,&ctm) != 3)
462 continue;
463
464 run_time = (time_t) ctm*60;
465
466 if ((S_IXUSR & buf.st_mode) && (run_time <=now)) {
467 if (isupper(queue) && (strcmp(batch_name,dirent->d_name) > 0)) {
468 run_batch = 1;
469 strncpy(batch_name, dirent->d_name, sizeof(batch_name));
470 batch_uid = buf.st_uid;
471 batch_gid = buf.st_gid;
472 }
473
474 /* The file is executable and old enough
475 */
476 if (islower(queue))
477 run_file(dirent->d_name, buf.st_uid, buf.st_gid);
478 }
479 /* Delete older files
480 */
481 if ((run_time < now) && !(S_IXUSR & buf.st_mode) && (S_IRUSR & buf.st_mode))
482 unlink(dirent->d_name);
483 }
484 /* run the single batch file, if any
485 */
486 if (run_batch && (gloadavg() < load_avg))
487 run_file(batch_name, batch_uid, batch_gid);
488
489 closelog();
490 exit(EXIT_SUCCESS);
491}
492
493static void
494usage(void)
495{
496 if (debug)
497 fprintf(stderr, "usage: atrun [-l load_avg] [-d]\n");
498 else
499 syslog(LOG_ERR, "usage: atrun [-l load_avg] [-d]");
500
501 exit(EXIT_FAILURE);
502}