| /* vi: set sw=4 ts=4: */ |
| /* |
| * setsid.c -- execute a command in a new session |
| * Rick Sladkey <jrs@world.std.com> |
| * In the public domain. |
| * |
| * 1999-02-22 Arkadiusz Mickiewicz <misiek@pld.ORG.PL> |
| * - added Native Language Support |
| * |
| * 2001-01-18 John Fremlin <vii@penguinpowered.com> |
| * - fork in case we are process group leader |
| * |
| * 2004-11-12 Paul Fox |
| * - busyboxed |
| */ |
| //config:config SETSID |
| //config: bool "setsid (3.9 kb)" |
| //config: default y |
| //config: help |
| //config: setsid runs a program in a new session |
| |
| //applet:IF_SETSID(APPLET(setsid, BB_DIR_USR_BIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_SETSID) += setsid.o |
| |
| //usage:#define setsid_trivial_usage |
| //usage: "[-c] PROG ARGS" |
| //usage:#define setsid_full_usage "\n\n" |
| //usage: "Run PROG in a new session. PROG will have no controlling terminal\n" |
| //usage: "and will not be affected by keyboard signals (^C etc).\n" |
| //usage: "\n -c Set controlling terminal to stdin" |
| |
| #include "libbb.h" |
| |
| int setsid_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int setsid_main(int argc UNUSED_PARAM, char **argv) |
| { |
| unsigned opt; |
| |
| /* +: stop on first non-opt */ |
| opt = getopt32(argv, "^+" "c" "\0" "-1"/* at least one arg */); |
| argv += optind; |
| |
| /* setsid() is allowed only when we are not a process group leader. |
| * Otherwise our PID serves as PGID of some existing process group |
| * and cannot be used as PGID of a new process group. |
| * |
| * Example: setsid() below fails when run alone in interactive shell: |
| * $ setsid PROG |
| * because shell's child (setsid) is put in a new process group. |
| * But doesn't fail if shell is not interactive |
| * (and therefore doesn't create process groups for pipes), |
| * or if setsid is not the first process in the process group: |
| * $ true | setsid PROG |
| * or if setsid is executed in backquotes (`setsid PROG`)... |
| */ |
| if (setsid() < 0) { |
| pid_t pid = fork_or_rexec(argv); |
| if (pid != 0) { |
| /* parent */ |
| /* TODO: |
| * we can waitpid(pid, &status, 0) and then even |
| * emulate exitcode, making the behavior consistent |
| * in both forked and non forked cases. |
| * However, the code is larger and upstream |
| * does not do such trick. |
| */ |
| return EXIT_SUCCESS; |
| } |
| |
| /* child */ |
| /* now there should be no error: */ |
| setsid(); |
| } |
| |
| if (opt) { |
| /* -c: set (with stealing) controlling tty */ |
| ioctl(0, TIOCSCTTY, 1); |
| } |
| |
| BB_EXECVP_or_die(argv); |
| } |