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| author | Alan Cox <alan@redhat.com> | 2008-10-13 10:40:30 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-13 09:51:41 -0700 |
| commit | 2cb5998b5f0ccc886fdda3509059eef297b49577 (patch) | |
| tree | 9113731d3f892c2e164bfd05a7cf1a4b1713a619 | |
| parent | 216ba023a96c04e8d3aabf83d5931c35b6e2dbbb (diff) | |
| download | linux-2cb5998b5f0ccc886fdda3509059eef297b49577.tar.gz linux-2cb5998b5f0ccc886fdda3509059eef297b49577.tar.bz2 linux-2cb5998b5f0ccc886fdda3509059eef297b49577.zip | |
tty: the vhangup syscall is racy
We now have the infrastructure to sort this out but rather than teaching
the syscall tty lock rules we move the hard work into a tty helper
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/char/tty_io.c | 19 | ||||
| -rw-r--r-- | fs/open.c | 3 | ||||
| -rw-r--r-- | include/linux/tty.h | 1 |
3 files changed, 21 insertions, 2 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 913b50258f90..b5f57d0b30ee 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -730,6 +730,25 @@ void tty_vhangup(struct tty_struct *tty) EXPORT_SYMBOL(tty_vhangup); /** + * tty_vhangup_self - process vhangup for own ctty + * + * Perform a vhangup on the current controlling tty + */ + +void tty_vhangup_self(void) +{ + struct tty_struct *tty; + + mutex_lock(&tty_mutex); + tty = get_current_tty(); + if (tty) { + tty_vhangup(tty); + tty_kref_put(tty); + } + mutex_unlock(&tty_mutex); +} + +/** * tty_hung_up_p - was tty hung up * @filp: file pointer of tty * diff --git a/fs/open.c b/fs/open.c index 07da9359481c..5596049863bf 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1141,8 +1141,7 @@ EXPORT_SYMBOL(sys_close); asmlinkage long sys_vhangup(void) { if (capable(CAP_SYS_TTY_CONFIG)) { - /* XXX: this needs locking */ - tty_vhangup(current->signal->tty); + tty_vhangup_self(); return 0; } return -EPERM; diff --git a/include/linux/tty.h b/include/linux/tty.h index c30ed8d3bcbd..e00393a3d1c9 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -361,6 +361,7 @@ extern int is_ignored(int sig); extern int tty_signal(int sig, struct tty_struct *tty); extern void tty_hangup(struct tty_struct *tty); extern void tty_vhangup(struct tty_struct *tty); +extern void tty_vhangup_self(void); extern void tty_unhangup(struct file *filp); extern int tty_hung_up_p(struct file *filp); extern void do_SAK(struct tty_struct *tty); |