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| author | Peter Korsgaard | 2011-11-09 19:44:37 +0100 |
|---|---|---|
| committer | Denys Vlasenko | 2011-11-09 19:44:37 +0100 |
| commit | 743edac6c84ac207d0bb4c3124b0e8fe450a38b4 (patch) | |
| tree | d74290b238665a3369e191dd85e7a4b38f74aadb /libbb | |
| parent | 7e21f0491cf3e72835cd9b515734caec56d41e70 (diff) | |
| download | busybox-743edac6c84ac207d0bb4c3124b0e8fe450a38b4.zip busybox-743edac6c84ac207d0bb4c3124b0e8fe450a38b4.tar.gz | |
bb_daemonize_or_rexec(): add flag to double-fork; use it in start-stop-daemon
Add a DAEMON_DOUBLE_FORK flag to make bb_daemonize double-fork so it isn't a
session leader, and hence doesn't get a controlling tty on Linux if a tty is
ever opened, similar to how libdaemon's daemon_fork or the big
start-stop-daemon does it - And use it in start-stop-daemon.
For details, see http://www.win.tue.nl/~aeb/linux/lk/lk-10.html#ss10.3
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'libbb')
| -rw-r--r-- | libbb/vfork_daemon_rexec.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c index a75eafb..ed1f86f 100644 --- a/libbb/vfork_daemon_rexec.c +++ b/libbb/vfork_daemon_rexec.c @@ -253,11 +253,19 @@ void FAST_FUNC bb_daemonize_or_rexec(int flags, char **argv) if (!(flags & DAEMON_ONLY_SANITIZE)) { if (fork_or_rexec(argv)) exit(EXIT_SUCCESS); /* parent */ - /* if daemonizing, make sure we detach from stdio & ctty */ + /* if daemonizing, detach from stdio & ctty */ setsid(); dup2(fd, 0); dup2(fd, 1); dup2(fd, 2); + if (flags & DAEMON_DOUBLE_FORK) { + /* On Linux, session leader can acquire ctty + * unknowingly, by opening a tty. + * Prevent this: stop being a session leader. + */ + if (fork_or_rexec(argv)) + exit(EXIT_SUCCESS); /* parent */ + } } while (fd > 2) { close(fd--); |