diff options
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 60 |
1 files changed, 57 insertions, 3 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 0c150b5a9dd6..974b13d24401 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -325,6 +325,56 @@ 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 /** @@ -1083,7 +1133,10 @@ 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]; @@ -1715,7 +1768,7 @@ 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; @@ -1748,7 +1801,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, * - concurrent tty driver removal w/ lookup * - concurrent tty removal from driver table */ -static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode, +struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode, struct file *filp) { struct tty_struct *tty; @@ -1793,6 +1846,7 @@ out: tty_driver_kref_put(driver); return tty; } +EXPORT_SYMBOL_GPL(tty_open_by_driver); /** * tty_open - open a tty device |