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tty: Combine SIGTTOU/SIGTTIN handling

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The job_control() check in n_tty_read() has nearly identical purpose
and results as tty_check_change(). Both functions' purpose is to
determine if the current task's pgrp is the foreground pgrp for the tty,
and if not, to signal the current pgrp.

Introduce __tty_check_change() which takes the signal to send
and performs the shared operations for job control() and
tty_check_change().

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2015-10-10 20:28:42 -04:00 committed by Greg Kroah-Hartman
parent 71a5cd8a4a
commit 2812d9e9fd
3 changed files with 27 additions and 46 deletions
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26
drivers/tty/n_tty.c
View file

@ -2138,37 +2138,15 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *,
static int job_control(struct tty_struct *tty, struct file *file)
{
struct pid *pgrp;
/* Job control check -- must be done at start and after
every sleep (POSIX.1 7.1.1.4). */
/* NOTE: not yet done after every sleep pending a thorough
check of the logic of this change. -- jlc */
/* don't stop on /dev/console */
if (file->f_op->write == redirected_tty_write ||
current->signal->tty != tty)
if (file->f_op->write == redirected_tty_write)
return 0;
rcu_read_lock();
pgrp = task_pgrp(current);
spin_lock_irq(&tty->ctrl_lock);
if (!tty->pgrp)
printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
else if (pgrp != tty->pgrp) {
spin_unlock_irq(&tty->ctrl_lock);
if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) {
rcu_read_unlock();
return -EIO;
}
kill_pgrp(pgrp, SIGTTIN, 1);
rcu_read_unlock();
set_thread_flag(TIF_SIGPENDING);
return -ERESTARTSYS;
}
spin_unlock_irq(&tty->ctrl_lock);
rcu_read_unlock();
return 0;
return __tty_check_change(tty, SIGTTIN);
}

46
drivers/tty/tty_io.c
View file

@ -390,10 +390,10 @@ EXPORT_SYMBOL_GPL(tty_find_polling_driver);
* Locking: ctrl_lock
*/
int tty_check_change(struct tty_struct *tty)
int __tty_check_change(struct tty_struct *tty, int sig)
{
unsigned long flags;
struct pid *pgrp;
struct pid *pgrp, *tty_pgrp;
int ret = 0;
if (current->signal->tty != tty)
@ -403,33 +403,35 @@ int tty_check_change(struct tty_struct *tty)
pgrp = task_pgrp(current);
spin_lock_irqsave(&tty->ctrl_lock, flags);
if (!tty->pgrp) {
printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
goto out_unlock;
}
if (pgrp == tty->pgrp)
goto out_unlock;
tty_pgrp = tty->pgrp;
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
if (is_ignored(SIGTTOU))
goto out_rcuunlock;
if (is_current_pgrp_orphaned()) {
ret = -EIO;
goto out_rcuunlock;
if (tty_pgrp && pgrp != tty->pgrp) {
if (is_ignored(sig)) {
if (sig == SIGTTIN)
ret = -EIO;
} else if (is_current_pgrp_orphaned())
ret = -EIO;
else {
kill_pgrp(pgrp, sig, 1);
set_thread_flag(TIF_SIGPENDING);
ret = -ERESTARTSYS;
}
}
kill_pgrp(pgrp, SIGTTOU, 1);
rcu_read_unlock();
set_thread_flag(TIF_SIGPENDING);
ret = -ERESTARTSYS;
return ret;
out_unlock:
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
out_rcuunlock:
rcu_read_unlock();
if (!tty_pgrp) {
pr_warn("%s: tty_check_change: sig=%d, tty->pgrp == NULL!\n",
tty_name(tty), sig);
}
return ret;
}
int tty_check_change(struct tty_struct *tty)
{
return __tty_check_change(tty, SIGTTOU);
}
EXPORT_SYMBOL(tty_check_change);
static ssize_t hung_up_tty_read(struct file *file, char __user *buf,

1
include/linux/tty.h
View file

@ -423,6 +423,7 @@ extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
const char *routine);
extern const char *tty_name(const struct tty_struct *tty);
extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
extern int __tty_check_change(struct tty_struct *tty, int sig);
extern int tty_check_change(struct tty_struct *tty);
extern void __stop_tty(struct tty_struct *tty);
extern void stop_tty(struct tty_struct *tty);