/* Semaphore 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 *);
*/
+/**
+ * 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
kfree(thead);
}
tty->buf.tail = NULL;
+ tty->buf.memory_used = 0;
}
+/**
+ * tty_buffer_init - prepare a tty buffer structure
+ * @tty: tty to initialise
+ *
+ * Set up the initial state of the buffer management for a tty device.
+ * Must be called before the other tty buffer functions are used.
+ *
+ * Locking: none
+ */
+
static void tty_buffer_init(struct tty_struct *tty)
{
spin_lock_init(&tty->buf.lock);
tty->buf.head = NULL;
tty->buf.tail = NULL;
tty->buf.free = NULL;
+ tty->buf.memory_used = 0;
}
-static struct tty_buffer *tty_buffer_alloc(size_t size)
+/**
+ * tty_buffer_alloc - allocate a tty buffer
+ * @tty: tty device
+ * @size: desired size (characters)
+ *
+ * Allocate a new tty buffer to hold the desired number of characters.
+ * Return NULL if out of memory or the allocation would exceed the
+ * per device queue
+ *
+ * Locking: Caller must hold tty->buf.lock
+ */
+
+static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
{
- struct tty_buffer *p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
+ struct tty_buffer *p;
+
+ if (tty->buf.memory_used + size > 65536)
+ return NULL;
+ p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
if(p == NULL)
return NULL;
p->used = 0;
p->read = 0;
p->char_buf_ptr = (char *)(p->data);
p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
-/* printk("Flip create %p\n", p); */
+ tty->buf.memory_used += size;
return p;
}
-/* Must be called with the tty_read lock held. This needs to acquire strategy
- code to decide if we should kfree or relink a given expired buffer */
+/**
+ * tty_buffer_free - free a tty buffer
+ * @tty: tty owning the buffer
+ * @b: the buffer to free
+ *
+ * Free a tty buffer, or add it to the free list according to our
+ * internal strategy
+ *
+ * Locking: Caller must hold tty->buf.lock
+ */
static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
{
/* Dumb strategy for now - should keep some stats */
-/* printk("Flip dispose %p\n", b); */
+ tty->buf.memory_used -= b->size;
+ WARN_ON(tty->buf.memory_used < 0);
+
if(b->size >= 512)
kfree(b);
else {
}
}
+/**
+ * tty_buffer_find - find a free tty buffer
+ * @tty: tty owning the buffer
+ * @size: characters wanted
+ *
+ * Locate an existing suitable tty buffer or if we are lacking one then
+ * allocate a new one. We round our buffers off in 256 character chunks
+ * to get better allocation behaviour.
+ *
+ * Locking: Caller must hold tty->buf.lock
+ */
+
static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
{
struct tty_buffer **tbh = &tty->buf.free;
t->used = 0;
t->commit = 0;
t->read = 0;
- /* DEBUG ONLY */
-/* memset(t->data, '*', size); */
-/* printk("Flip recycle %p\n", t); */
+ tty->buf.memory_used += t->size;
return t;
}
tbh = &((*tbh)->next);
}
/* Round the buffer size out */
size = (size + 0xFF) & ~ 0xFF;
- return tty_buffer_alloc(size);
+ return tty_buffer_alloc(tty, size);
/* Should possibly check if this fails for the largest buffer we
have queued and recycle that ? */
}
+/**
+ * tty_buffer_request_room - grow tty buffer if needed
+ * @tty: tty structure
+ * @size: size desired
+ *
+ * Make at least size bytes of linear space available for the tty
+ * buffer. If we fail return the size we managed to find.
+ *
+ * Locking: Takes tty->buf.lock
+ */
int tty_buffer_request_room(struct tty_struct *tty, size_t size)
{
struct tty_buffer *b, *n;
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);
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);
}
/*
*/
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 */
/* call the tty release_mem routine to clean out this slot */
release_mem_out:
- printk(KERN_INFO "init_dev: ldisc open failed, "
- "clearing slot %d\n", idx);
+ if (printk_ratelimit())
+ printk(KERN_INFO "init_dev: ldisc open failed, "
+ "clearing slot %d\n", idx);
release_mem(tty, idx);
goto end_init;
}
* 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_sem 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_sem is used to ensure we don't double
+ * resize and get confused. Lock order - tty->termios.sem 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;
}
* 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
*
*/
} else
return -EPERM;
}
+ mutex_lock(&tty_mutex);
task_lock(current);
current->signal->tty = tty;
task_unlock(current);
+ mutex_unlock(&tty_mutex);
current->signal->tty_old_pgrp = 0;
tty->session = current->signal->session;
tty->pgrp = process_group(current);
* 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)
* 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)
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);
* This field is optional, if there is no known struct device
* for this tty device it can be set to NULL safely.
*
- * Returns a pointer to the class device (or ERR_PTR(-EFOO) on error).
+ * Returns a pointer to the struct device for this tty device
+ * (or ERR_PTR(-EFOO) on error).
*
* This call is required to be made to register an individual tty device
* if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
* Locking: ??
*/
-struct class_device *tty_register_device(struct tty_driver *driver,
- unsigned index, struct device *device)
+struct device *tty_register_device(struct tty_driver *driver, unsigned index,
+ struct device *device)
{
char name[64];
dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
else
tty_line_name(driver, index, name);
- return class_device_create(tty_class, NULL, dev, device, "%s", name);
+ return device_create(tty_class, device, dev, name);
}
/**
void tty_unregister_device(struct tty_driver *driver, unsigned index)
{
- class_device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index);
+ device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index);
}
EXPORT_SYMBOL(tty_register_device);
kfree(driver);
}
-void tty_set_operations(struct tty_driver *driver, struct tty_operations *op)
+void tty_set_operations(struct tty_driver *driver,
+ const struct tty_operations *op)
{
driver->open = op->open;
driver->close = op->close;
if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
panic("Couldn't register /dev/tty driver\n");
- class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
+ device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty");
cdev_init(&console_cdev, &console_fops);
if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
panic("Couldn't register /dev/console driver\n");
- class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL, "console");
+ device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console");
#ifdef CONFIG_UNIX98_PTYS
cdev_init(&ptmx_cdev, &ptmx_fops);
if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
panic("Couldn't register /dev/ptmx driver\n");
- class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
+ device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx");
#endif
#ifdef CONFIG_VT
if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
panic("Couldn't register /dev/tty0 driver\n");
- class_device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0");
+ device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0");
vty_init();
#endif
projects / linux-2.6 / blobdiff