From d01c3289e7d68162e32bc08c2b65dd1a216a7ef8 Mon Sep 17 00:00:00 2001 From: Masatake YAMATO Date: Tue, 18 Jul 2017 06:27:59 +0900 Subject: [PATCH] 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/pty.c | 8 +++++++- drivers/tty/tty_io.c | 9 +++++++++ include/linux/tty_driver.h | 2 ++ 3 files changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 284749f..bb672ac 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 = { diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 974b13d..c3c8fd0 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 = { diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 00b2213..fcdc0f5 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -243,6 +243,7 @@ #include #include #include +#include struct tty_struct; struct tty_driver; @@ -285,6 +286,7 @@ struct tty_operations { int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew); int (*get_icount)(struct tty_struct *tty, struct serial_icounter_struct *icount); + void (*show_fdinfo)(struct tty_struct *tty, struct seq_file *m); #ifdef CONFIG_CONSOLE_POLL int (*poll_init)(struct tty_driver *driver, int line, char *options); int (*poll_get_char)(struct tty_driver *driver, int line); -- 2.7.4