1 files changed, 180 insertions, 129 deletions

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 3fdebd306b9..e41b9bbc107 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -790,19 +790,24 @@ static void session_clear_tty(struct pid *session)
 void disassociate_ctty(int on_exit)
 {
 	struct tty_struct *tty;
-	struct pid *tty_pgrp = NULL;
 
 	if (!current->signal->leader)
 		return;
 
 	tty = get_current_tty();
 	if (tty) {
-		tty_pgrp = get_pid(tty->pgrp);
+		struct pid *tty_pgrp = get_pid(tty->pgrp);
 		if (on_exit) {
 			if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
 				tty_vhangup(tty);
 		}
 		tty_kref_put(tty);
+		if (tty_pgrp) {
+			kill_pgrp(tty_pgrp, SIGHUP, on_exit);
+			if (!on_exit)
+				kill_pgrp(tty_pgrp, SIGCONT, on_exit);
+			put_pid(tty_pgrp);
+		}
 	} else if (on_exit) {
 		struct pid *old_pgrp;
 		spin_lock_irq(&current->sighand->siglock);
@@ -816,12 +821,6 @@ void disassociate_ctty(int on_exit)
 		}
 		return;
 	}
-	if (tty_pgrp) {
-		kill_pgrp(tty_pgrp, SIGHUP, on_exit);
-		if (!on_exit)
-			kill_pgrp(tty_pgrp, SIGCONT, on_exit);
-		put_pid(tty_pgrp);
-	}
 
 	spin_lock_irq(&current->sighand->siglock);
 	put_pid(current->signal->tty_old_pgrp);
@@ -1558,6 +1557,59 @@ static void release_tty(struct tty_struct *tty, int idx)
 }
 
 /**
+ *	tty_release_checks - check a tty before real release
+ *	@tty: tty to check
+ *	@o_tty: link of @tty (if any)
+ *	@idx: index of the tty
+ *
+ *	Performs some paranoid checking before true release of the @tty.
+ *	This is a no-op unless TTY_PARANOIA_CHECK is defined.
+ */
+static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
+		int idx)
+{
+#ifdef TTY_PARANOIA_CHECK
+	if (idx < 0 || idx >= tty->driver->num) {
+		printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
+				__func__, tty->name);
+		return -1;
+	}
+
+	/* not much to check for devpts */
+	if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
+		return 0;
+
+	if (tty != tty->driver->ttys[idx]) {
+		printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
+				__func__, idx, tty->name);
+		return -1;
+	}
+	if (tty->termios != tty->driver->termios[idx]) {
+		printk(KERN_DEBUG "%s: driver.termios[%d] not termios for (%s)\n",
+				__func__, idx, tty->name);
+		return -1;
+	}
+	if (tty->driver->other) {
+		if (o_tty != tty->driver->other->ttys[idx]) {
+			printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
+					__func__, idx, tty->name);
+			return -1;
+		}
+		if (o_tty->termios != tty->driver->other->termios[idx]) {
+			printk(KERN_DEBUG "%s: other->termios[%d] not o_termios for (%s)\n",
+					__func__, idx, tty->name);
+			return -1;
+		}
+		if (o_tty->link != tty) {
+			printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
+			return -1;
+		}
+	}
+#endif
+	return 0;
+}
+
+/**
  *	tty_release		-	vfs callback for close
  *	@inode: inode of tty
  *	@filp: file pointer for handle to tty
@@ -1585,11 +1637,11 @@ int tty_release(struct inode *inode, struct file *filp)
 	int	idx;
 	char	buf[64];
 
-	if (tty_paranoia_check(tty, inode, "tty_release_dev"))
+	if (tty_paranoia_check(tty, inode, __func__))
 		return 0;
 
 	tty_lock();
-	check_tty_count(tty, "tty_release_dev");
+	check_tty_count(tty, __func__);
 
 	__tty_fasync(-1, filp, 0);
 
@@ -1599,59 +1651,16 @@ int tty_release(struct inode *inode, struct file *filp)
 	devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
 	o_tty = tty->link;
 
-#ifdef TTY_PARANOIA_CHECK
-	if (idx < 0 || idx >= tty->driver->num) {
-		printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
-				  "free (%s)\n", tty->name);
+	if (tty_release_checks(tty, o_tty, idx)) {
 		tty_unlock();
 		return 0;
 	}
-	if (!devpts) {
-		if (tty != tty->driver->ttys[idx]) {
-			tty_unlock();
-			printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
-			       "for (%s)\n", idx, tty->name);
-			return 0;
-		}
-		if (tty->termios != tty->driver->termios[idx]) {
-			tty_unlock();
-			printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
-			       "for (%s)\n",
-			       idx, tty->name);
-			return 0;
-		}
-	}
-#endif
 
 #ifdef TTY_DEBUG_HANGUP
-	printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
-	       tty_name(tty, buf), tty->count);
+	printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
+			tty_name(tty, buf), tty->count);
 #endif
 
-#ifdef TTY_PARANOIA_CHECK
-	if (tty->driver->other &&
-	     !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
-		if (o_tty != tty->driver->other->ttys[idx]) {
-			tty_unlock();
-			printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
-					  "not o_tty for (%s)\n",
-			       idx, tty->name);
-			return 0 ;
-		}
-		if (o_tty->termios != tty->driver->other->termios[idx]) {
-			tty_unlock();
-			printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
-					  "not o_termios for (%s)\n",
-			       idx, tty->name);
-			return 0;
-		}
-		if (o_tty->link != tty) {
-			tty_unlock();
-			printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
-			return 0;
-		}
-	}
-#endif
 	if (tty->ops->close)
 		tty->ops->close(tty, filp);
 
@@ -1707,8 +1716,8 @@ int tty_release(struct inode *inode, struct file *filp)
 		if (!do_sleep)
 			break;
 
-		printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
-				    "active!\n", tty_name(tty, buf));
+		printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
+				__func__, tty_name(tty, buf));
 		tty_unlock();
 		mutex_unlock(&tty_mutex);
 		schedule();
@@ -1721,15 +1730,14 @@ int tty_release(struct inode *inode, struct file *filp)
 	 */
 	if (pty_master) {
 		if (--o_tty->count < 0) {
-			printk(KERN_WARNING "tty_release_dev: bad pty slave count "
-					    "(%d) for %s\n",
-			       o_tty->count, tty_name(o_tty, buf));
+			printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
+				__func__, o_tty->count, tty_name(o_tty, buf));
 			o_tty->count = 0;
 		}
 	}
 	if (--tty->count < 0) {
-		printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
-		       tty->count, tty_name(tty, buf));
+		printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
+				__func__, tty->count, tty_name(tty, buf));
 		tty->count = 0;
 	}
 
@@ -1778,7 +1786,7 @@ int tty_release(struct inode *inode, struct file *filp)
 	}
 
 #ifdef TTY_DEBUG_HANGUP
-	printk(KERN_DEBUG "freeing tty structure...");
+	printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
 #endif
 	/*
 	 * Ask the line discipline code to release its structures
@@ -1798,6 +1806,83 @@ int tty_release(struct inode *inode, struct file *filp)
 }
 
 /**
+ *	tty_open_current_tty - get tty of current task for open
+ *	@device: device number
+ *	@filp: file pointer to tty
+ *	@return: tty of the current task iff @device is /dev/tty
+ *
+ *	We cannot return driver and index like for the other nodes because
+ *	devpts will not work then. It expects inodes to be from devpts FS.
+ */
+static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
+{
+	struct tty_struct *tty;
+
+	if (device != MKDEV(TTYAUX_MAJOR, 0))
+		return NULL;
+
+	tty = get_current_tty();
+	if (!tty)
+		return ERR_PTR(-ENXIO);
+
+	filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
+	/* noctty = 1; */
+	tty_kref_put(tty);
+	/* FIXME: we put a reference and return a TTY! */
+	return tty;
+}
+
+/**
+ *	tty_lookup_driver - lookup a tty driver for a given device file
+ *	@device: device number
+ *	@filp: file pointer to tty
+ *	@noctty: set if the device should not become a controlling tty
+ *	@index: index for the device in the @return driver
+ *	@return: driver for this inode (with increased refcount)
+ *
+ * 	If @return is not erroneous, the caller is responsible to decrement the
+ * 	refcount by tty_driver_kref_put.
+ *
+ *	Locking: tty_mutex protects get_tty_driver
+ */
+static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
+		int *noctty, int *index)
+{
+	struct tty_driver *driver;
+
+	switch (device) {
+#ifdef CONFIG_VT
+	case MKDEV(TTY_MAJOR, 0): {
+		extern struct tty_driver *console_driver;
+		driver = tty_driver_kref_get(console_driver);
+		*index = fg_console;
+		*noctty = 1;
+		break;
+	}
+#endif
+	case MKDEV(TTYAUX_MAJOR, 1): {
+		struct tty_driver *console_driver = console_device(index);
+		if (console_driver) {
+			driver = tty_driver_kref_get(console_driver);
+			if (driver) {
+				/* Don't let /dev/console block */
+				filp->f_flags |= O_NONBLOCK;
+				*noctty = 1;
+				break;
+			}
+		}
+		return ERR_PTR(-ENODEV);
+	}
+	default:
+		driver = get_tty_driver(device, index);
+		if (!driver)
+			return ERR_PTR(-ENODEV);
+		break;
+	}
+	return driver;
+}
+
+/**
  *	tty_open		-	open a tty device
  *	@inode: inode of device file
  *	@filp: file pointer to tty
@@ -1813,16 +1898,16 @@ int tty_release(struct inode *inode, struct file *filp)
  *	The termios state of a pty is reset on first open so that
  *	settings don't persist across reuse.
  *
- *	Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
+ *	Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
  *		 tty->count should protect the rest.
  *		 ->siglock protects ->signal/->sighand
  */
 
 static int tty_open(struct inode *inode, struct file *filp)
 {
-	struct tty_struct *tty = NULL;
+	struct tty_struct *tty;
 	int noctty, retval;
-	struct tty_driver *driver;
+	struct tty_driver *driver = NULL;
 	int index;
 	dev_t device = inode->i_rdev;
 	unsigned saved_flags = filp->f_flags;
@@ -1841,66 +1926,22 @@ retry_open:
 	mutex_lock(&tty_mutex);
 	tty_lock();
 
-	if (device == MKDEV(TTYAUX_MAJOR, 0)) {
-		tty = get_current_tty();
-		if (!tty) {
-			tty_unlock();
-			mutex_unlock(&tty_mutex);
-			tty_free_file(filp);
-			return -ENXIO;
-		}
-		driver = tty_driver_kref_get(tty->driver);
-		index = tty->index;
-		filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
-		/* noctty = 1; */
-		/* FIXME: Should we take a driver reference ? */
-		tty_kref_put(tty);
-		goto got_driver;
-	}
-#ifdef CONFIG_VT
-	if (device == MKDEV(TTY_MAJOR, 0)) {
-		extern struct tty_driver *console_driver;
-		driver = tty_driver_kref_get(console_driver);
-		index = fg_console;
-		noctty = 1;
-		goto got_driver;
-	}
-#endif
-	if (device == MKDEV(TTYAUX_MAJOR, 1)) {
-		struct tty_driver *console_driver = console_device(&index);
-		if (console_driver) {
-			driver = tty_driver_kref_get(console_driver);
-			if (driver) {
-				/* Don't let /dev/console block */
-				filp->f_flags |= O_NONBLOCK;
-				noctty = 1;
-				goto got_driver;
-			}
+	tty = tty_open_current_tty(device, filp);
+	if (IS_ERR(tty)) {
+		retval = PTR_ERR(tty);
+		goto err_unlock;
+	} else if (!tty) {
+		driver = tty_lookup_driver(device, filp, &noctty, &index);
+		if (IS_ERR(driver)) {
+			retval = PTR_ERR(driver);
+			goto err_unlock;
 		}
-		tty_unlock();
-		mutex_unlock(&tty_mutex);
-		tty_free_file(filp);
-		return -ENODEV;
-	}
 
-	driver = get_tty_driver(device, &index);
-	if (!driver) {
-		tty_unlock();
-		mutex_unlock(&tty_mutex);
-		tty_free_file(filp);
-		return -ENODEV;
-	}
-got_driver:
-	if (!tty) {
 		/* check whether we're reopening an existing tty */
 		tty = tty_driver_lookup_tty(driver, inode, index);
-
 		if (IS_ERR(tty)) {
-			tty_unlock();
-			mutex_unlock(&tty_mutex);
-			tty_driver_kref_put(driver);
-			tty_free_file(filp);
-			return PTR_ERR(tty);
+			retval = PTR_ERR(tty);
+			goto err_unlock;
 		}
 	}
 
@@ -1912,21 +1953,22 @@ got_driver:
 		tty = tty_init_dev(driver, index, 0);
 
 	mutex_unlock(&tty_mutex);
-	tty_driver_kref_put(driver);
+	if (driver)
+		tty_driver_kref_put(driver);
 	if (IS_ERR(tty)) {
 		tty_unlock();
-		tty_free_file(filp);
-		return PTR_ERR(tty);
+		retval = PTR_ERR(tty);
+		goto err_file;
 	}
 
 	tty_add_file(tty, filp);
 
-	check_tty_count(tty, "tty_open");
+	check_tty_count(tty, __func__);
 	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
 	    tty->driver->subtype == PTY_TYPE_MASTER)
 		noctty = 1;
 #ifdef TTY_DEBUG_HANGUP
-	printk(KERN_DEBUG "opening %s...", tty->name);
+	printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
 #endif
 	if (tty->ops->open)
 		retval = tty->ops->open(tty, filp);
@@ -1940,8 +1982,8 @@ got_driver:
 
 	if (retval) {
 #ifdef TTY_DEBUG_HANGUP
-		printk(KERN_DEBUG "error %d in opening %s...", retval,
-		       tty->name);
+		printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
+				retval, tty->name);
 #endif
 		tty_unlock(); /* need to call tty_release without BTM */
 		tty_release(inode, filp);
@@ -1976,6 +2018,15 @@ got_driver:
 	tty_unlock();
 	mutex_unlock(&tty_mutex);
 	return 0;
+err_unlock:
+	tty_unlock();
+	mutex_unlock(&tty_mutex);
+	/* after locks to avoid deadlock */
+	if (!IS_ERR_OR_NULL(driver))
+		tty_driver_kref_put(driver);
+err_file:
+	tty_free_file(filp);
+	return retval;
 }