openvt,getty,vfork_daemon_rexec,mount: tighten up fd cleanup code

[platform/upstream/busybox.git] / networking / telnetd.c

diff --git a/networking/telnetd.c b/networking/telnetd.c
index 51bd0c0..25cba3e 100644 (file)
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -283,15 +283,19 @@ make_new_session(
 
        /* child */
 
+       /* make new process group */
+       setsid();
+       tcsetpgrp(0, getpid());
+       /* ^^^ strace says: "ioctl(0, TIOCSPGRP, [pid]) = -1 ENOTTY" -- ??! */
+
        /* open the child's side of the tty. */
-       fd = xopen(tty_name, O_RDWR /*| O_NOCTTY*/);
+       /* NB: setsid() disconnects from any previous ctty's. Therefore
+        * we must open child's side of the tty AFTER setsid! */
+       fd = xopen(tty_name, O_RDWR); /* becomes our ctty */
        dup2(fd, 0);
        dup2(fd, 1);
        dup2(fd, 2);
        while (fd > 2) close(fd--);
-       /* make new process group */
-       setsid();
-       tcsetpgrp(0, getpid());
 
        /* The pseudo-terminal allocated to the client is configured to operate in
         * cooked mode, and with XTABS CRMOD enabled (see tty(4)). */