tty: Signal foreground group processes in hangup

[linux-2.6-block.git] / drivers / tty / tty_io.c

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 2661e86a2272b26425a7db759c277c610508ce35..3feca406dc369ea18693d11a62caf58526971b9f 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -534,18 +534,21 @@ EXPORT_SYMBOL_GPL(tty_wakeup);
 
 /**
  *     tty_signal_session_leader       - sends SIGHUP to session leader
+ *     @tty            controlling tty
+ *     @exit_session   if non-zero, signal all foreground group processes
  *
- *     Send SIGHUP and SIGCONT to the session leader and its
- *     process group.
+ *     Send SIGHUP and SIGCONT to the session leader and its process group.
+ *     Optionally, signal all processes in the foreground process group.
  *
  *     Returns the number of processes in the session with this tty
  *     as their controlling terminal. This value is used to drop
  *     tty references for those processes.
  */
-static int tty_signal_session_leader(struct tty_struct *tty)
+static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
 {
        struct task_struct *p;
        int refs = 0;
+       struct pid *tty_pgrp = NULL;
 
        read_lock(&tasklist_lock);
        if (tty->session) {
@@ -565,6 +568,7 @@ static int tty_signal_session_leader(struct tty_struct *tty)
                        __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
                        put_pid(p->signal->tty_old_pgrp);  /* A noop */
                        spin_lock(&tty->ctrl_lock);
+                       tty_pgrp = get_pid(tty->pgrp);
                        if (tty->pgrp)
                                p->signal->tty_old_pgrp = get_pid(tty->pgrp);
                        spin_unlock(&tty->ctrl_lock);
@@ -573,6 +577,12 @@ static int tty_signal_session_leader(struct tty_struct *tty)
        }
        read_unlock(&tasklist_lock);
 
+       if (tty_pgrp) {
+               if (exit_session)
+                       kill_pgrp(tty_pgrp, SIGHUP, exit_session);
+               put_pid(tty_pgrp);
+       }
+
        return refs;
 }
 
@@ -598,7 +608,7 @@ static int tty_signal_session_leader(struct tty_struct *tty)
  *               tasklist_lock to walk task list for hangup event
  *                 ->siglock to protect ->signal/->sighand
  */
-static void __tty_hangup(struct tty_struct *tty)
+static void __tty_hangup(struct tty_struct *tty, int exit_session)
 {
        struct file *cons_filp = NULL;
        struct file *filp, *f = NULL;
@@ -647,7 +657,7 @@ static void __tty_hangup(struct tty_struct *tty)
         */
        tty_ldisc_hangup(tty);
 
-       refs = tty_signal_session_leader(tty);
+       refs = tty_signal_session_leader(tty, exit_session);
        /* Account for the p->signal references we killed */
        while (refs--)
                tty_kref_put(tty);
@@ -696,7 +706,7 @@ static void do_tty_hangup(struct work_struct *work)
        struct tty_struct *tty =
                container_of(work, struct tty_struct, hangup_work);
 
-       __tty_hangup(tty);
+       __tty_hangup(tty, 0);
 }
 
 /**
@@ -734,7 +744,7 @@ void tty_vhangup(struct tty_struct *tty)
 
        printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
 #endif
-       __tty_hangup(tty);
+       __tty_hangup(tty, 0);
 }
 
 EXPORT_SYMBOL(tty_vhangup);
@@ -757,6 +767,27 @@ void tty_vhangup_self(void)
        }
 }
 
+/**
+ *     tty_vhangup_session             -       hangup session leader exit
+ *     @tty: tty to hangup
+ *
+ *     The session leader is exiting and hanging up its controlling terminal.
+ *     Every process in the foreground process group is signalled SIGHUP.
+ *
+ *     We do this synchronously so that when the syscall returns the process
+ *     is complete. That guarantee is necessary for security reasons.
+ */
+
+void tty_vhangup_session(struct tty_struct *tty)
+{
+#ifdef TTY_DEBUG_HANGUP
+       char    buf[64];
+
+       printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
+#endif
+       __tty_hangup(tty, 1);
+}
+
 /**
  *     tty_hung_up_p           -       was tty hung up
  *     @filp: file pointer of tty
@@ -814,18 +845,18 @@ void disassociate_ctty(int on_exit)
 
        tty = get_current_tty();
        if (tty) {
-               struct pid *tty_pgrp = get_pid(tty->pgrp);
-               if (on_exit) {
-                       if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
-                               tty_vhangup(tty);
-               }
-               tty_kref_put(tty);
-               if (tty_pgrp) {
-                       kill_pgrp(tty_pgrp, SIGHUP, on_exit);
-                       if (!on_exit)
+               if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
+                       tty_vhangup_session(tty);
+               } else {
+                       struct pid *tty_pgrp = tty_get_pgrp(tty);
+                       if (tty_pgrp) {
+                               kill_pgrp(tty_pgrp, SIGHUP, on_exit);
                                kill_pgrp(tty_pgrp, SIGCONT, on_exit);
-                       put_pid(tty_pgrp);
+                               put_pid(tty_pgrp);
+                       }
                }
+               tty_kref_put(tty);
+
        } else if (on_exit) {
                struct pid *old_pgrp;
                spin_lock_irq(&current->sighand->siglock);