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path: root/drivers/char/tty_io.c
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Diffstat (limited to 'drivers/char/tty_io.c')
-rw-r--r--drivers/char/tty_io.c92
1 files changed, 63 insertions, 29 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 0350c42375a2..949067a0bd47 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -136,6 +136,9 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */
DEFINE_MUTEX(tty_mutex);
EXPORT_SYMBOL(tty_mutex);
+/* Spinlock to protect the tty->tty_files list */
+DEFINE_SPINLOCK(tty_files_lock);
+
static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
ssize_t redirected_tty_write(struct file *, const char __user *,
@@ -185,6 +188,41 @@ void free_tty_struct(struct tty_struct *tty)
kfree(tty);
}
+static inline struct tty_struct *file_tty(struct file *file)
+{
+ return ((struct tty_file_private *)file->private_data)->tty;
+}
+
+/* Associate a new file with the tty structure */
+void tty_add_file(struct tty_struct *tty, struct file *file)
+{
+ struct tty_file_private *priv;
+
+ /* XXX: must implement proper error handling in callers */
+ priv = kmalloc(sizeof(*priv), GFP_KERNEL|__GFP_NOFAIL);
+
+ priv->tty = tty;
+ priv->file = file;
+ file->private_data = priv;
+
+ spin_lock(&tty_files_lock);
+ list_add(&priv->list, &tty->tty_files);
+ spin_unlock(&tty_files_lock);
+}
+
+/* Delete file from its tty */
+void tty_del_file(struct file *file)
+{
+ struct tty_file_private *priv = file->private_data;
+
+ spin_lock(&tty_files_lock);
+ list_del(&priv->list);
+ spin_unlock(&tty_files_lock);
+ file->private_data = NULL;
+ kfree(priv);
+}
+
+
#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
/**
@@ -235,11 +273,11 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
struct list_head *p;
int count = 0;
- file_list_lock();
+ spin_lock(&tty_files_lock);
list_for_each(p, &tty->tty_files) {
count++;
}
- file_list_unlock();
+ spin_unlock(&tty_files_lock);
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_SLAVE &&
tty->link && tty->link->count)
@@ -497,6 +535,7 @@ void __tty_hangup(struct tty_struct *tty)
struct file *cons_filp = NULL;
struct file *filp, *f = NULL;
struct task_struct *p;
+ struct tty_file_private *priv;
int closecount = 0, n;
unsigned long flags;
int refs = 0;
@@ -506,7 +545,7 @@ void __tty_hangup(struct tty_struct *tty)
spin_lock(&redirect_lock);
- if (redirect && redirect->private_data == tty) {
+ if (redirect && file_tty(redirect) == tty) {
f = redirect;
redirect = NULL;
}
@@ -519,9 +558,10 @@ void __tty_hangup(struct tty_struct *tty)
workqueue with the lock held */
check_tty_count(tty, "tty_hangup");
- file_list_lock();
+ spin_lock(&tty_files_lock);
/* This breaks for file handles being sent over AF_UNIX sockets ? */
- list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
+ list_for_each_entry(priv, &tty->tty_files, list) {
+ filp = priv->file;
if (filp->f_op->write == redirected_tty_write)
cons_filp = filp;
if (filp->f_op->write != tty_write)
@@ -530,7 +570,7 @@ void __tty_hangup(struct tty_struct *tty)
__tty_fasync(-1, filp, 0); /* can't block */
filp->f_op = &hung_up_tty_fops;
}
- file_list_unlock();
+ spin_unlock(&tty_files_lock);
tty_ldisc_hangup(tty);
@@ -889,12 +929,10 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
loff_t *ppos)
{
int i;
- struct tty_struct *tty;
- struct inode *inode;
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct tty_struct *tty = file_tty(file);
struct tty_ldisc *ld;
- tty = file->private_data;
- inode = file->f_path.dentry->d_inode;
if (tty_paranoia_check(tty, inode, "tty_read"))
return -EIO;
if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
@@ -1065,12 +1103,11 @@ void tty_write_message(struct tty_struct *tty, char *msg)
static ssize_t tty_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- struct tty_struct *tty;
struct inode *inode = file->f_path.dentry->d_inode;
+ struct tty_struct *tty = file_tty(file);
+ struct tty_ldisc *ld;
ssize_t ret;
- struct tty_ldisc *ld;
- tty = file->private_data;
if (tty_paranoia_check(tty, inode, "tty_write"))
return -EIO;
if (!tty || !tty->ops->write ||
@@ -1424,9 +1461,9 @@ static void release_one_tty(struct work_struct *work)
tty_driver_kref_put(driver);
module_put(driver->owner);
- file_list_lock();
+ spin_lock(&tty_files_lock);
list_del_init(&tty->tty_files);
- file_list_unlock();
+ spin_unlock(&tty_files_lock);
put_pid(tty->pgrp);
put_pid(tty->session);
@@ -1507,13 +1544,13 @@ static void release_tty(struct tty_struct *tty, int idx)
int tty_release(struct inode *inode, struct file *filp)
{
- struct tty_struct *tty, *o_tty;
+ struct tty_struct *tty = file_tty(filp);
+ struct tty_struct *o_tty;
int pty_master, tty_closing, o_tty_closing, do_sleep;
int devpts;
int idx;
char buf[64];
- tty = filp->private_data;
if (tty_paranoia_check(tty, inode, "tty_release_dev"))
return 0;
@@ -1671,8 +1708,7 @@ int tty_release(struct inode *inode, struct file *filp)
* - do_tty_hangup no longer sees this file descriptor as
* something that needs to be handled for hangups.
*/
- file_kill(filp);
- filp->private_data = NULL;
+ tty_del_file(filp);
/*
* Perform some housekeeping before deciding whether to return.
@@ -1839,8 +1875,8 @@ got_driver:
return PTR_ERR(tty);
}
- filp->private_data = tty;
- file_move(filp, &tty->tty_files);
+ tty_add_file(tty, filp);
+
check_tty_count(tty, "tty_open");
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)
@@ -1916,11 +1952,10 @@ got_driver:
static unsigned int tty_poll(struct file *filp, poll_table *wait)
{
- struct tty_struct *tty;
+ struct tty_struct *tty = file_tty(filp);
struct tty_ldisc *ld;
int ret = 0;
- tty = filp->private_data;
if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
return 0;
@@ -1933,11 +1968,10 @@ static unsigned int tty_poll(struct file *filp, poll_table *wait)
static int __tty_fasync(int fd, struct file *filp, int on)
{
- struct tty_struct *tty;
+ struct tty_struct *tty = file_tty(filp);
unsigned long flags;
int retval = 0;
- tty = filp->private_data;
if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
goto out;
@@ -2491,13 +2525,13 @@ EXPORT_SYMBOL(tty_pair_get_pty);
*/
long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
- struct tty_struct *tty, *real_tty;
+ struct tty_struct *tty = file_tty(file);
+ struct tty_struct *real_tty;
void __user *p = (void __user *)arg;
int retval;
struct tty_ldisc *ld;
struct inode *inode = file->f_dentry->d_inode;
- tty = file->private_data;
if (tty_paranoia_check(tty, inode, "tty_ioctl"))
return -EINVAL;
@@ -2619,7 +2653,7 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct inode *inode = file->f_dentry->d_inode;
- struct tty_struct *tty = file->private_data;
+ struct tty_struct *tty = file_tty(file);
struct tty_ldisc *ld;
int retval = -ENOIOCTLCMD;
@@ -2711,7 +2745,7 @@ void __do_SAK(struct tty_struct *tty)
if (!filp)
continue;
if (filp->f_op->read == tty_read &&
- filp->private_data == tty) {
+ file_tty(filp) == tty) {
printk(KERN_NOTICE "SAK: killed process %d"
" (%s): fd#%d opened to the tty\n",
task_pid_nr(p), p->comm, i);