tty: avoid recursive BTM in pty_close

[mv-sheeva.git] / drivers / char / pty.c

diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index d83a43130df433962d7b0764ef6fc9c59f781f81..ad46eae1f9bb207847fd8ac2bf80b58d4f3922d8 100644 (file)
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -62,7 +62,9 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
                if (tty->driver == ptm_driver)
                        devpts_pty_kill(tty->link);
 #endif
+               tty_unlock();
                tty_vhangup(tty->link);
+               tty_lock();
        }
 }
 
@@ -171,6 +173,23 @@ static int pty_set_lock(struct tty_struct *tty, int __user *arg)
        return 0;
 }
 
+/* Send a signal to the slave */
+static int pty_signal(struct tty_struct *tty, int sig)
+{
+       unsigned long flags;
+       struct pid *pgrp;
+
+       if (tty->link) {
+               spin_lock_irqsave(&tty->link->ctrl_lock, flags);
+               pgrp = get_pid(tty->link->pgrp);
+               spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
+
+               kill_pgrp(pgrp, sig, 1);
+               put_pid(pgrp);
+       }
+       return 0;
+}
+
 static void pty_flush_buffer(struct tty_struct *tty)
 {
        struct tty_struct *to = tty->link;
@@ -321,6 +340,8 @@ static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
        switch (cmd) {
        case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
                return pty_set_lock(tty, (int __user *) arg);
+       case TIOCSIG:    /* Send signal to other side of pty */
+               return pty_signal(tty, (int) arg);
        }
        return -ENOIOCTLCMD;
 }
@@ -476,6 +497,8 @@ static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
                return pty_set_lock(tty, (int __user *)arg);
        case TIOCGPTN: /* Get PT Number */
                return put_user(tty->index, (unsigned int __user *)arg);
+       case TIOCSIG:    /* Send signal to other side of pty */
+               return pty_signal(tty, (int) arg);
        }
 
        return -ENOIOCTLCMD;
@@ -626,7 +649,7 @@ static const struct tty_operations pty_unix98_ops = {
  *             allocated_ptys_lock handles the list of free pty numbers
  */
 
-static int __ptmx_open(struct inode *inode, struct file *filp)
+static int ptmx_open(struct inode *inode, struct file *filp)
 {
        struct tty_struct *tty;
        int retval;
@@ -635,11 +658,14 @@ static int __ptmx_open(struct inode *inode, struct file *filp)
        nonseekable_open(inode, filp);
 
        /* find a device that is not in use. */
+       tty_lock();
        index = devpts_new_index(inode);
+       tty_unlock();
        if (index < 0)
                return index;
 
        mutex_lock(&tty_mutex);
+       tty_lock();
        tty = tty_init_dev(ptm_driver, index, 1);
        mutex_unlock(&tty_mutex);
 
@@ -657,26 +683,21 @@ static int __ptmx_open(struct inode *inode, struct file *filp)
                goto out1;
 
        retval = ptm_driver->ops->open(tty, filp);
-       if (!retval)
-               return 0;
+       if (retval)
+               goto out2;
 out1:
+       tty_unlock();
+       return retval;
+out2:
+       tty_unlock();
        tty_release(inode, filp);
        return retval;
 out:
        devpts_kill_index(inode, index);
+       tty_unlock();
        return retval;
 }
 
-static int ptmx_open(struct inode *inode, struct file *filp)
-{
-       int ret;
-
-       lock_kernel();
-       ret = __ptmx_open(inode, filp);
-       unlock_kernel();
-       return ret;
-}
-
 static struct file_operations ptmx_fops;
 
 static void __init unix98_pty_init(void)