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path: root/drivers/tty/tty_io.c
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Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r--drivers/tty/tty_io.c169
1 files changed, 162 insertions, 7 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 0c150b5a9dd6..94cccb6efa32 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -280,7 +280,7 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
{
#ifdef CHECK_TTY_COUNT
struct list_head *p;
- int count = 0;
+ int count = 0, kopen_count = 0;
spin_lock(&tty->files_lock);
list_for_each(p, &tty->tty_files) {
@@ -291,10 +291,12 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
tty->driver->subtype == PTY_TYPE_SLAVE &&
tty->link && tty->link->count)
count++;
- if (tty->count != count) {
- tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
- routine, tty->count, count);
- return count;
+ if (tty_port_kopened(tty->port))
+ kopen_count++;
+ if (tty->count != (count + kopen_count)) {
+ tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
+ routine, tty->count, count, kopen_count);
+ return (count + kopen_count);
}
#endif
return 0;
@@ -325,6 +327,56 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index)
return NULL;
}
+/**
+ * tty_dev_name_to_number - return dev_t for device name
+ * @name: user space name of device under /dev
+ * @number: pointer to dev_t that this function will populate
+ *
+ * This function converts device names like ttyS0 or ttyUSB1 into dev_t
+ * like (4, 64) or (188, 1). If no corresponding driver is registered then
+ * the function returns -ENODEV.
+ *
+ * Locking: this acquires tty_mutex to protect the tty_drivers list from
+ * being modified while we are traversing it, and makes sure to
+ * release it before exiting.
+ */
+int tty_dev_name_to_number(const char *name, dev_t *number)
+{
+ struct tty_driver *p;
+ int ret;
+ int index, prefix_length = 0;
+ const char *str;
+
+ for (str = name; *str && !isdigit(*str); str++)
+ ;
+
+ if (!*str)
+ return -EINVAL;
+
+ ret = kstrtoint(str, 10, &index);
+ if (ret)
+ return ret;
+
+ prefix_length = str - name;
+ mutex_lock(&tty_mutex);
+
+ list_for_each_entry(p, &tty_drivers, tty_drivers)
+ if (prefix_length == strlen(p->name) && strncmp(name,
+ p->name, prefix_length) == 0) {
+ if (index < p->num) {
+ *number = MKDEV(p->major, p->minor_start + index);
+ goto out;
+ }
+ }
+
+ /* if here then driver wasn't found */
+ ret = -ENODEV;
+out:
+ mutex_unlock(&tty_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
+
#ifdef CONFIG_CONSOLE_POLL
/**
@@ -412,6 +464,14 @@ static int hung_up_tty_fasync(int fd, struct file *file, int on)
return -ENOTTY;
}
+static void tty_show_fdinfo(struct seq_file *m, struct file *file)
+{
+ struct tty_struct *tty = file_tty(file);
+
+ if (tty && tty->ops && tty->ops->show_fdinfo)
+ tty->ops->show_fdinfo(tty, m);
+}
+
static const struct file_operations tty_fops = {
.llseek = no_llseek,
.read = tty_read,
@@ -422,6 +482,7 @@ static const struct file_operations tty_fops = {
.open = tty_open,
.release = tty_release,
.fasync = tty_fasync,
+ .show_fdinfo = tty_show_fdinfo,
};
static const struct file_operations console_fops = {
@@ -1083,7 +1144,10 @@ static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
struct tty_struct *tty;
if (driver->ops->lookup)
- tty = driver->ops->lookup(driver, file, idx);
+ if (!file)
+ tty = ERR_PTR(-EIO);
+ else
+ tty = driver->ops->lookup(driver, file, idx);
else
tty = driver->ttys[idx];
@@ -1460,6 +1524,38 @@ static int tty_release_checks(struct tty_struct *tty, int idx)
}
/**
+ * tty_kclose - closes tty opened by tty_kopen
+ * @tty: tty device
+ *
+ * Performs the final steps to release and free a tty device. It is the
+ * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
+ * flag on tty->port.
+ */
+void tty_kclose(struct tty_struct *tty)
+{
+ /*
+ * Ask the line discipline code to release its structures
+ */
+ tty_ldisc_release(tty);
+
+ /* Wait for pending work before tty destruction commmences */
+ tty_flush_works(tty);
+
+ tty_debug_hangup(tty, "freeing structure\n");
+ /*
+ * The release_tty function takes care of the details of clearing
+ * the slots and preserving the termios structure. The tty_unlock_pair
+ * should be safe as we keep a kref while the tty is locked (so the
+ * unlock never unlocks a freed tty).
+ */
+ mutex_lock(&tty_mutex);
+ tty_port_set_kopened(tty->port, 0);
+ release_tty(tty, tty->index);
+ mutex_unlock(&tty_mutex);
+}
+EXPORT_SYMBOL_GPL(tty_kclose);
+
+/**
* tty_release_struct - release a tty struct
* @tty: tty device
* @idx: index of the tty
@@ -1715,7 +1811,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
struct tty_driver *console_driver = console_device(index);
if (console_driver) {
driver = tty_driver_kref_get(console_driver);
- if (driver) {
+ if (driver && filp) {
/* Don't let /dev/console block */
filp->f_flags |= O_NONBLOCK;
break;
@@ -1733,6 +1829,56 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
}
/**
+ * tty_kopen - open a tty device for kernel
+ * @device: dev_t of device to open
+ *
+ * Opens tty exclusively for kernel. Performs the driver lookup,
+ * makes sure it's not already opened and performs the first-time
+ * tty initialization.
+ *
+ * Returns the locked initialized &tty_struct
+ *
+ * Claims the global tty_mutex to serialize:
+ * - concurrent first-time tty initialization
+ * - concurrent tty driver removal w/ lookup
+ * - concurrent tty removal from driver table
+ */
+struct tty_struct *tty_kopen(dev_t device)
+{
+ struct tty_struct *tty;
+ struct tty_driver *driver = NULL;
+ int index = -1;
+
+ mutex_lock(&tty_mutex);
+ driver = tty_lookup_driver(device, NULL, &index);
+ if (IS_ERR(driver)) {
+ mutex_unlock(&tty_mutex);
+ return ERR_CAST(driver);
+ }
+
+ /* check whether we're reopening an existing tty */
+ tty = tty_driver_lookup_tty(driver, NULL, index);
+ if (IS_ERR(tty))
+ goto out;
+
+ if (tty) {
+ /* drop kref from tty_driver_lookup_tty() */
+ tty_kref_put(tty);
+ tty = ERR_PTR(-EBUSY);
+ } else { /* tty_init_dev returns tty with the tty_lock held */
+ tty = tty_init_dev(driver, index);
+ if (IS_ERR(tty))
+ goto out;
+ tty_port_set_kopened(tty->port, 1);
+ }
+out:
+ mutex_unlock(&tty_mutex);
+ tty_driver_kref_put(driver);
+ return tty;
+}
+EXPORT_SYMBOL_GPL(tty_kopen);
+
+/**
* tty_open_by_driver - open a tty device
* @device: dev_t of device to open
* @inode: inode of device file
@@ -1771,6 +1917,12 @@ static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
}
if (tty) {
+ if (tty_port_kopened(tty->port)) {
+ tty_kref_put(tty);
+ mutex_unlock(&tty_mutex);
+ tty = ERR_PTR(-EBUSY);
+ goto out;
+ }
mutex_unlock(&tty_mutex);
retval = tty_lock_interruptible(tty);
tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
@@ -2464,6 +2616,9 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case TIOCSSERIAL:
tty_warn_deprecated_flags(p);
break;
+ case TIOCGPTPEER:
+ /* Special because the struct file is needed */
+ return ptm_open_peer(file, tty, (int)arg);
default:
retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
if (retval != -ENOIOCTLCMD)
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