Messages in this thread Patch in this message | | | From | Masatake YAMATO <> | Subject | [PATCH v2 resend] pty: show associative slave of ptmx in fdinfo | Date | Mon, 14 Aug 2017 23:41:46 +0900 |
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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.
Change in v2:
Remove all #ifdef CONFIG_PROC_FS/#endif. Suggested by Greg KH.
Signed-off-by: Masatake YAMATO <yamato@redhat.com> --- 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 d1399aa..ce27be4 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -742,6 +742,11 @@ 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, @@ -756,7 +761,8 @@ 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 b742b5e..570b05b 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -243,6 +243,7 @@ #include <linux/list.h> #include <linux/cdev.h> #include <linux/termios.h> +#include <linux/seq_file.h> 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); -- 2.9.4
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