udhcpc: fix a problem with binary-encoded options #2

[oweals/busybox.git] / libbb / vfork_daemon_rexec.c

diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c
index a75eafbd3e96def9552a4b5386637d6081cfce57..ed1f86f0c5748383ba63b9c95253de72532e631e 100644 (file)
--- 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--);