diff options
| author | Masatake YAMATO <yamato@redhat.com> | 2017-07-18 06:27:59 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-08-28 20:51:23 +0200 |
| commit | d01c3289e7d68162e32bc08c2b65dd1a216a7ef8 (patch) | |
| tree | 34177b1e85f857b838fa75b08153d091472eb775 /drivers/tty/pty.c | |
| parent | 199e717f252be0e31c97b9c7861dd6e2abfaa936 (diff) | |
pty: show associative slave of ptmx in fdinfo
This patch adds "tty-index" field to /proc/PID/fdinfo/N if N
specifies /dev/ptmx. The field shows the index of associative
slave pts.
Though a minor number is given for each pts instance, ptmx is not.
It means there is no way in user-space to know the association between
file descriptors for pts/n and ptmx. (n = 0, 1, ...)
This is different from pipe. About pipe such association can be solved
by inode of pipefs.
Providing the way to know the association between pts/n and ptmx helps
users understand the status of running system. lsof can utilize this field.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/pty.c')
| -rw-r--r-- | drivers/tty/pty.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 284749fb0f6b..bb672ace562f 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -741,6 +741,11 @@ static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) } } +static void pty_show_fdinfo(struct tty_struct *tty, struct seq_file *m) +{ + seq_printf(m, "tty-index:\t%d\n", tty->index); +} + static const struct tty_operations ptm_unix98_ops = { .lookup = ptm_unix98_lookup, .install = pty_unix98_install, @@ -755,7 +760,8 @@ static const struct tty_operations ptm_unix98_ops = { .ioctl = pty_unix98_ioctl, .compat_ioctl = pty_unix98_compat_ioctl, .resize = pty_resize, - .cleanup = pty_cleanup + .cleanup = pty_cleanup, + .show_fdinfo = pty_show_fdinfo, }; static const struct tty_operations pty_unix98_ops = { |