LIST_HEAD(tty_drivers); /* linked list of tty drivers */
-/* Semaphore to protect creating and releasing a tty. This is shared with
+/* Mutex to protect creating and releasing a tty. This is shared with
vt.c for deeply disgusting hack reasons */
DEFINE_MUTEX(tty_mutex);
+EXPORT_SYMBOL(tty_mutex);
#ifdef CONFIG_UNIX98_PTYS
extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */
* been initialized in any way but has been zeroed
*
* Locking: none
- * FIXME: use kzalloc
*/
static struct tty_struct *alloc_tty_struct(void)
{
- struct tty_struct *tty;
-
- tty = kmalloc(sizeof(struct tty_struct), GFP_KERNEL);
- if (tty)
- memset(tty, 0, sizeof(struct tty_struct));
- return tty;
+ return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
}
static void tty_buffer_free_all(struct tty_struct *);
"!= #fd's(%d) in %s\n",
tty->name, tty->count, count, routine);
return count;
- }
+ }
#endif
return 0;
}
* Tty buffer allocation management
*/
-
-/**
- * tty_buffer_free_all - free buffers used by a tty
- * @tty: tty to free from
- *
- * Remove all the buffers pending on a tty whether queued with data
- * or in the free ring. Must be called when the tty is no longer in use
- *
- * Locking: none
- */
-
-
/**
* tty_buffer_free_all - free buffers used by a tty
* @tty: tty to free from
tb->used += space;
copied += space;
chars += space;
- }
- /* There is a small chance that we need to split the data over
- several buffers. If this is the case we must loop */
- while (unlikely(size > copied));
+ /* There is a small chance that we need to split the data over
+ several buffers. If this is the case we must loop */
+ } while (unlikely(size > copied));
return copied;
}
EXPORT_SYMBOL(tty_insert_flip_string);
copied += space;
chars += space;
flags += space;
- }
- /* There is a small chance that we need to split the data over
- several buffers. If this is the case we must loop */
- while (unlikely(size > copied));
+ /* There is a small chance that we need to split the data over
+ several buffers. If this is the case we must loop */
+ } while (unlikely(size > copied));
return copied;
}
EXPORT_SYMBOL(tty_insert_flip_string_flags);
* they are not on hot paths so a little discipline won't do
* any harm.
*
- * Locking: takes termios_sem
+ * Locking: takes termios_mutex
*/
static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
{
- down(&tty->termios_sem);
+ mutex_lock(&tty->termios_mutex);
tty->termios->c_line = num;
- up(&tty->termios_sem);
+ mutex_unlock(&tty->termios_mutex);
}
/*
* context.
*
* Locking: takes tty_ldisc_lock.
- * called functions take termios_sem
+ * called functions take termios_mutex
*/
static int tty_set_ldisc(struct tty_struct *tty, int ldisc)
*
* Locking:
* BKL
- * redirect lock for undoing redirection
- * file list lock for manipulating list of ttys
- * tty_ldisc_lock from called functions
- * termios_sem resetting termios data
- * tasklist_lock to walk task list for hangup event
- *
+ * redirect lock for undoing redirection
+ * file list lock for manipulating list of ttys
+ * tty_ldisc_lock from called functions
+ * termios_mutex resetting termios data
+ * tasklist_lock to walk task list for hangup event
+ * ->siglock to protect ->signal/->sighand
*/
static void do_tty_hangup(void *data)
{
*/
if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
{
- down(&tty->termios_sem);
+ mutex_lock(&tty->termios_mutex);
*tty->termios = tty->driver->init_termios;
- up(&tty->termios_sem);
+ mutex_unlock(&tty->termios_mutex);
}
/* Defer ldisc switch */
read_lock(&tasklist_lock);
if (tty->session > 0) {
do_each_task_pid(tty->session, PIDTYPE_SID, p) {
+ spin_lock_irq(&p->sighand->siglock);
if (p->signal->tty == tty)
p->signal->tty = NULL;
- if (!p->signal->leader)
+ if (!p->signal->leader) {
+ spin_unlock_irq(&p->sighand->siglock);
continue;
- group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
- group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
+ }
+ __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
+ __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
if (tty->pgrp > 0)
p->signal->tty_old_pgrp = tty->pgrp;
+ spin_unlock_irq(&p->sighand->siglock);
} while_each_task_pid(tty->session, PIDTYPE_SID, p);
}
read_unlock(&tasklist_lock);
EXPORT_SYMBOL(tty_hung_up_p);
+static void session_clear_tty(pid_t session)
+{
+ struct task_struct *p;
+ do_each_task_pid(session, PIDTYPE_SID, p) {
+ proc_clear_tty(p);
+ } while_each_task_pid(session, PIDTYPE_SID, p);
+}
+
/**
* disassociate_ctty - disconnect controlling tty
* @on_exit: true if exiting so need to "hang up" the session
* The argument on_exit is set to 1 if called when a process is
* exiting; it is 0 if called by the ioctl TIOCNOTTY.
*
- * Locking: tty_mutex is taken to protect current->signal->tty
+ * Locking:
* BKL is taken for hysterical raisins
- * Tasklist lock is taken (under tty_mutex) to walk process
- * lists for the session.
+ * tty_mutex is taken to protect tty
+ * ->siglock is taken to protect ->signal/->sighand
+ * tasklist_lock is taken to walk process list for sessions
+ * ->siglock is taken to protect ->signal/->sighand
*/
void disassociate_ctty(int on_exit)
{
struct tty_struct *tty;
- struct task_struct *p;
int tty_pgrp = -1;
+ int session;
lock_kernel();
mutex_lock(&tty_mutex);
- tty = current->signal->tty;
+ tty = get_current_tty();
if (tty) {
tty_pgrp = tty->pgrp;
mutex_unlock(&tty_mutex);
+ /* XXX: here we race, there is nothing protecting tty */
if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
tty_vhangup(tty);
} else {
- if (current->signal->tty_old_pgrp) {
- kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit);
- kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit);
+ pid_t old_pgrp = current->signal->tty_old_pgrp;
+ if (old_pgrp) {
+ kill_pg(old_pgrp, SIGHUP, on_exit);
+ kill_pg(old_pgrp, SIGCONT, on_exit);
}
mutex_unlock(&tty_mutex);
unlock_kernel();
kill_pg(tty_pgrp, SIGCONT, on_exit);
}
- /* Must lock changes to tty_old_pgrp */
- mutex_lock(&tty_mutex);
+ spin_lock_irq(¤t->sighand->siglock);
current->signal->tty_old_pgrp = 0;
- tty->session = 0;
- tty->pgrp = -1;
+ session = current->signal->session;
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ mutex_lock(&tty_mutex);
+ /* It is possible that do_tty_hangup has free'd this tty */
+ tty = get_current_tty();
+ if (tty) {
+ tty->session = 0;
+ tty->pgrp = 0;
+ } else {
+#ifdef TTY_DEBUG_HANGUP
+ printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
+ " = NULL", tty);
+#endif
+ }
+ mutex_unlock(&tty_mutex);
/* Now clear signal->tty under the lock */
read_lock(&tasklist_lock);
- do_each_task_pid(current->signal->session, PIDTYPE_SID, p) {
- p->signal->tty = NULL;
- } while_each_task_pid(current->signal->session, PIDTYPE_SID, p);
+ session_clear_tty(session);
read_unlock(&tasklist_lock);
- mutex_unlock(&tty_mutex);
unlock_kernel();
}
* tty.
*/
if (tty_closing || o_tty_closing) {
- struct task_struct *p;
-
read_lock(&tasklist_lock);
- do_each_task_pid(tty->session, PIDTYPE_SID, p) {
- p->signal->tty = NULL;
- } while_each_task_pid(tty->session, PIDTYPE_SID, p);
+ session_clear_tty(tty->session);
if (o_tty)
- do_each_task_pid(o_tty->session, PIDTYPE_SID, p) {
- p->signal->tty = NULL;
- } while_each_task_pid(o_tty->session, PIDTYPE_SID, p);
+ session_clear_tty(o_tty->session);
read_unlock(&tasklist_lock);
}
* The termios state of a pty is reset on first open so that
* settings don't persist across reuse.
*
- * Locking: tty_mutex protects current->signal->tty, get_tty_driver and
- * init_dev work. tty->count should protect the rest.
- * task_lock is held to update task details for sessions
+ * Locking: tty_mutex protects tty, get_tty_driver and init_dev work.
+ * tty->count should protect the rest.
+ * ->siglock protects ->signal/->sighand
*/
static int tty_open(struct inode * inode, struct file * filp)
mutex_lock(&tty_mutex);
if (device == MKDEV(TTYAUX_MAJOR,0)) {
- if (!current->signal->tty) {
+ tty = get_current_tty();
+ if (!tty) {
mutex_unlock(&tty_mutex);
return -ENXIO;
}
- driver = current->signal->tty->driver;
- index = current->signal->tty->index;
+ driver = tty->driver;
+ index = tty->index;
filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
/* noctty = 1; */
goto got_driver;
filp->f_op = &tty_fops;
goto retry_open;
}
+
+ mutex_lock(&tty_mutex);
+ spin_lock_irq(¤t->sighand->siglock);
if (!noctty &&
current->signal->leader &&
!current->signal->tty &&
- tty->session == 0) {
- task_lock(current);
- current->signal->tty = tty;
- task_unlock(current);
- current->signal->tty_old_pgrp = 0;
- tty->session = current->signal->session;
- tty->pgrp = process_group(current);
- }
+ tty->session == 0)
+ __proc_set_tty(current, tty);
+ spin_unlock_irq(¤t->sighand->siglock);
+ mutex_unlock(&tty_mutex);
return 0;
}
* Locking:
* Called functions take tty_ldisc_lock
* current->signal->tty check is safe without locks
+ *
+ * FIXME: may race normal receive processing
*/
static int tiocsti(struct tty_struct *tty, char __user *p)
* @tty; tty
* @arg: user buffer for result
*
- * Copies the kernel idea of the window size into the user buffer. No
- * locking is done.
+ * Copies the kernel idea of the window size into the user buffer.
*
- * FIXME: Returning random values racing a window size set is wrong
- * should lock here against that
+ * Locking: tty->termios_mutex is taken to ensure the winsize data
+ * is consistent.
*/
static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg)
{
- if (copy_to_user(arg, &tty->winsize, sizeof(*arg)))
- return -EFAULT;
- return 0;
+ int err;
+
+ mutex_lock(&tty->termios_mutex);
+ err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
+ mutex_unlock(&tty->termios_mutex);
+
+ return err ? -EFAULT: 0;
}
/**
* actually has driver level meaning and triggers a VC resize.
*
* Locking:
- * The console_sem is used to ensure we do not try and resize
- * the console twice at once.
- * FIXME: Two racing size sets may leave the console and kernel
- * parameters disagreeing. Is this exploitable ?
- * FIXME: Random values racing a window size get is wrong
- * should lock here against that
+ * Called function use the console_sem is used to ensure we do
+ * not try and resize the console twice at once.
+ * The tty->termios_mutex is used to ensure we don't double
+ * resize and get confused. Lock order - tty->termios_mutex before
+ * console sem
*/
static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
return -EFAULT;
+
+ mutex_lock(&tty->termios_mutex);
if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg)))
- return 0;
+ goto done;
+
#ifdef CONFIG_VT
if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) {
- int rc;
-
- acquire_console_sem();
- rc = vc_resize(tty->driver_data, tmp_ws.ws_col, tmp_ws.ws_row);
- release_console_sem();
- if (rc)
- return -ENXIO;
+ if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col,
+ tmp_ws.ws_row)) {
+ mutex_unlock(&tty->termios_mutex);
+ return -ENXIO;
+ }
}
#endif
if (tty->pgrp > 0)
kill_pg(real_tty->pgrp, SIGWINCH, 1);
tty->winsize = tmp_ws;
real_tty->winsize = tmp_ws;
+done:
+ mutex_unlock(&tty->termios_mutex);
return 0;
}
* leader to set this tty as the controlling tty for the session.
*
* Locking:
- * Takes tasklist lock internally to walk sessions
- * Takes task_lock() when updating signal->tty
- *
- * FIXME: tty_mutex is needed to protect signal->tty references.
- * FIXME: why task_lock on the signal->tty reference ??
- *
+ * Takes tty_mutex() to protect tty instance
+ * Takes tasklist_lock internally to walk sessions
+ * Takes ->siglock() when updating signal->tty
*/
static int tiocsctty(struct tty_struct *tty, int arg)
{
- struct task_struct *p;
-
+ int ret = 0;
if (current->signal->leader &&
(current->signal->session == tty->session))
- return 0;
+ return ret;
+
+ mutex_lock(&tty_mutex);
/*
* The process must be a session leader and
* not have a controlling tty already.
*/
- if (!current->signal->leader || current->signal->tty)
- return -EPERM;
+ if (!current->signal->leader || current->signal->tty) {
+ ret = -EPERM;
+ goto unlock;
+ }
+
if (tty->session > 0) {
/*
* This tty is already the controlling
/*
* Steal it away
*/
-
read_lock(&tasklist_lock);
- do_each_task_pid(tty->session, PIDTYPE_SID, p) {
- p->signal->tty = NULL;
- } while_each_task_pid(tty->session, PIDTYPE_SID, p);
+ session_clear_tty(tty->session);
read_unlock(&tasklist_lock);
- } else
- return -EPERM;
+ } else {
+ ret = -EPERM;
+ goto unlock;
+ }
}
- task_lock(current);
- current->signal->tty = tty;
- task_unlock(current);
- current->signal->tty_old_pgrp = 0;
- tty->session = current->signal->session;
- tty->pgrp = process_group(current);
- return 0;
+ proc_set_tty(current, tty);
+unlock:
+ mutex_unlock(&tty_mutex);
+ return ret;
}
/**
* Obtain the process group of the tty. If there is no process group
* return an error.
*
- * Locking: none. Reference to ->signal->tty is safe.
+ * Locking: none. Reference to current->signal->tty is safe.
*/
static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
* permitted where the tty session is our session.
*
* Locking: None
- *
- * FIXME: current->signal->tty referencing is unsafe.
*/
static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
* Obtain the session id of the tty. If there is no session
* return an error.
*
- * Locking: none. Reference to ->signal->tty is safe.
+ * Locking: none. Reference to current->signal->tty is safe.
*/
static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
* timed break functionality.
*
* Locking:
- * None
+ * atomic_write_lock serializes
*
- * FIXME:
- * What if two overlap
*/
static int send_break(struct tty_struct *tty, unsigned int duration)
{
+ if (mutex_lock_interruptible(&tty->atomic_write_lock))
+ return -EINTR;
tty->driver->break_ctl(tty, -1);
if (!signal_pending(current)) {
msleep_interruptible(duration);
}
tty->driver->break_ctl(tty, 0);
+ mutex_unlock(&tty->atomic_write_lock);
if (signal_pending(current))
return -EINTR;
return 0;
if (tty_paranoia_check(tty, inode, "tty_ioctl"))
return -EINVAL;
+ /* CHECKME: is this safe as one end closes ? */
+
real_tty = tty;
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)
clear_bit(TTY_EXCLUSIVE, &tty->flags);
return 0;
case TIOCNOTTY:
- /* FIXME: taks lock or tty_mutex ? */
if (current->signal->tty != tty)
return -ENOTTY;
if (current->signal->leader)
disassociate_ctty(0);
- task_lock(current);
- current->signal->tty = NULL;
- task_unlock(current);
+ proc_clear_tty(current);
return 0;
case TIOCSCTTY:
return tiocsctty(tty, arg);
if (!tty)
return;
- session = tty->session;
+ session = tty->session;
/* We don't want an ldisc switch during this */
disc = tty_ldisc_ref(tty);
tty_buffer_init(tty);
INIT_WORK(&tty->buf.work, flush_to_ldisc, tty);
init_MUTEX(&tty->buf.pty_sem);
- init_MUTEX(&tty->termios_sem);
+ mutex_init(&tty->termios_mutex);
init_waitqueue_head(&tty->write_wait);
init_waitqueue_head(&tty->read_wait);
INIT_WORK(&tty->hangup_work, do_tty_hangup, tty);
git://git.onelab.eu / linux-2.6.git / blobdiff