From d01c3289e7d68162e32bc08c2b65dd1a216a7ef8 Mon Sep 17 00:00:00 2001 From: Masatake YAMATO Date: Tue, 18 Jul 2017 06:27:59 +0900 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/tty/tty_io.c') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 974b13d24401..c3c8fd0ed535 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -462,6 +462,14 @@ static int hung_up_tty_fasync(int fd, struct file *file, int on) return -ENOTTY; } +static void tty_show_fdinfo(struct seq_file *m, struct file *file) +{ + struct tty_struct *tty = file_tty(file); + + if (tty && tty->ops && tty->ops->show_fdinfo) + tty->ops->show_fdinfo(tty, m); +} + static const struct file_operations tty_fops = { .llseek = no_llseek, .read = tty_read, @@ -472,6 +480,7 @@ static const struct file_operations tty_fops = { .open = tty_open, .release = tty_release, .fasync = tty_fasync, + .show_fdinfo = tty_show_fdinfo, }; static const struct file_operations console_fops = { -- cgit