Bernhard Reutner-Fischer | c89982d | 2006-06-03 19:49:21 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
Paul Fox | 4240364 | 2005-08-01 22:52:09 +0000 | [diff] [blame] | 2 | /* |
| 3 | * setsid.c -- execute a command in a new session |
| 4 | * Rick Sladkey <jrs@world.std.com> |
| 5 | * In the public domain. |
| 6 | * |
Denis Vlasenko | b44c790 | 2008-03-17 09:29:43 +0000 | [diff] [blame] | 7 | * 1999-02-22 Arkadiusz Mickiewicz <misiek@pld.ORG.PL> |
Paul Fox | 4240364 | 2005-08-01 22:52:09 +0000 | [diff] [blame] | 8 | * - added Native Language Support |
| 9 | * |
| 10 | * 2001-01-18 John Fremlin <vii@penguinpowered.com> |
| 11 | * - fork in case we are process group leader |
| 12 | * |
| 13 | * 2004-11-12 Paul Fox |
| 14 | * - busyboxed |
| 15 | */ |
| 16 | |
Pere Orga | 5bc8c00 | 2011-04-11 03:29:49 +0200 | [diff] [blame] | 17 | //usage:#define setsid_trivial_usage |
Denys Vlasenko | ccf7f0e | 2016-01-17 01:09:36 +0100 | [diff] [blame] | 18 | //usage: "[-c] PROG ARGS" |
Pere Orga | 5bc8c00 | 2011-04-11 03:29:49 +0200 | [diff] [blame] | 19 | //usage:#define setsid_full_usage "\n\n" |
| 20 | //usage: "Run PROG in a new session. PROG will have no controlling terminal\n" |
Denys Vlasenko | ccf7f0e | 2016-01-17 01:09:36 +0100 | [diff] [blame] | 21 | //usage: "and will not be affected by keyboard signals (^C etc).\n" |
| 22 | //usage: "\n -c Set controlling terminal to stdin" |
Pere Orga | 5bc8c00 | 2011-04-11 03:29:49 +0200 | [diff] [blame] | 23 | |
Denis Vlasenko | b6adbf1 | 2007-05-26 19:00:18 +0000 | [diff] [blame] | 24 | #include "libbb.h" |
Paul Fox | 4240364 | 2005-08-01 22:52:09 +0000 | [diff] [blame] | 25 | |
Denis Vlasenko | 9b49a5e | 2007-10-11 10:05:36 +0000 | [diff] [blame] | 26 | int setsid_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
Denis Vlasenko | a60f84e | 2008-07-05 09:18:54 +0000 | [diff] [blame] | 27 | int setsid_main(int argc UNUSED_PARAM, char **argv) |
Mike Frysinger | e1d41b3 | 2006-03-23 02:07:41 +0000 | [diff] [blame] | 28 | { |
Denys Vlasenko | ccf7f0e | 2016-01-17 01:09:36 +0100 | [diff] [blame] | 29 | unsigned opt; |
| 30 | |
| 31 | opt_complementary = "-1"; /* at least one arg */ |
Denys Vlasenko | 7cf45ae | 2016-06-20 23:50:26 +0200 | [diff] [blame] | 32 | opt = getopt32(argv, "+c"); /* +: stop on first non-opt */ |
Denys Vlasenko | ccf7f0e | 2016-01-17 01:09:36 +0100 | [diff] [blame] | 33 | argv += optind; |
Paul Fox | 4240364 | 2005-08-01 22:52:09 +0000 | [diff] [blame] | 34 | |
Denis Vlasenko | b44c790 | 2008-03-17 09:29:43 +0000 | [diff] [blame] | 35 | /* setsid() is allowed only when we are not a process group leader. |
| 36 | * Otherwise our PID serves as PGID of some existing process group |
Denys Vlasenko | a5e6c6c | 2013-08-07 18:49:51 +0200 | [diff] [blame] | 37 | * and cannot be used as PGID of a new process group. |
| 38 | * |
| 39 | * Example: setsid() below fails when run alone in interactive shell: |
| 40 | * $ setsid PROG |
| 41 | * because shell's child (setsid) is put in a new process group. |
| 42 | * But doesn't fail if shell is not interactive |
| 43 | * (and therefore doesn't create process groups for pipes), |
| 44 | * or if setsid is not the first process in the process group: |
| 45 | * $ true | setsid PROG |
| 46 | * or if setsid is executed in backquotes (`setsid PROG`)... |
| 47 | */ |
Denys Vlasenko | a29b055 | 2010-05-16 02:12:56 +0200 | [diff] [blame] | 48 | if (setsid() < 0) { |
| 49 | pid_t pid = fork_or_rexec(argv); |
| 50 | if (pid != 0) { |
| 51 | /* parent */ |
| 52 | /* TODO: |
| 53 | * we can waitpid(pid, &status, 0) and then even |
| 54 | * emulate exitcode, making the behavior consistent |
| 55 | * in both forked and non forked cases. |
| 56 | * However, the code is larger and upstream |
| 57 | * does not do such trick. |
| 58 | */ |
Denys Vlasenko | a5e6c6c | 2013-08-07 18:49:51 +0200 | [diff] [blame] | 59 | return EXIT_SUCCESS; |
Denys Vlasenko | a29b055 | 2010-05-16 02:12:56 +0200 | [diff] [blame] | 60 | } |
Paul Fox | 4240364 | 2005-08-01 22:52:09 +0000 | [diff] [blame] | 61 | |
Denys Vlasenko | a29b055 | 2010-05-16 02:12:56 +0200 | [diff] [blame] | 62 | /* child */ |
| 63 | /* now there should be no error: */ |
| 64 | setsid(); |
| 65 | } |
Paul Fox | 4240364 | 2005-08-01 22:52:09 +0000 | [diff] [blame] | 66 | |
Denys Vlasenko | ccf7f0e | 2016-01-17 01:09:36 +0100 | [diff] [blame] | 67 | if (opt) { |
| 68 | /* -c: set (with stealing) controlling tty */ |
| 69 | ioctl(0, TIOCSCTTY, 1); |
| 70 | } |
| 71 | |
Pascal Bellard | 21e8e8d | 2010-07-04 00:57:03 +0200 | [diff] [blame] | 72 | BB_EXECVP_or_die(argv); |
Paul Fox | 4240364 | 2005-08-01 22:52:09 +0000 | [diff] [blame] | 73 | } |