depends on SUN_LDOMS
help
Support for Sun logical domain consoles.
+
+config LDISC_AUTOLOAD
+ bool "Automatically load TTY Line Disciplines"
+ default y
+ help
+ Historically the kernel has always automatically loaded any
+ line discipline that is in a kernel module when a user asks
+ for it to be loaded with the TIOCSETD ioctl, or through other
+ means. This is not always the best thing to do on systems
+ where you know you will not be using some of the more
+ "ancient" line disciplines, so prevent the kernel from doing
+ this unless the request is coming from a process with the
+ CAP_SYS_MODULE permissions.
+
+ Say 'Y' here if you trust your userspace users to do the right
+ thing, or if you have only provided the line disciplines that
+ you know you will be using, or if you wish to continue to use
+ the traditional method of on-demand loading of these modules
+ by any user.
+
+ This functionality can be changed at runtime with the
+ dev.tty.ldisc_autoload sysctl, this configuration option will
+ only set the default value of this functionality.
+
endif # TTY
static DEFINE_SPINLOCK(redirect_lock);
static struct file *redirect;
+extern void tty_sysctl_init(void);
+
/**
* tty_wakeup - request more data
* @tty: terminal
*/
int __init tty_init(void)
{
+ tty_sysctl_init();
cdev_init(&tty_cdev, &tty_fops);
if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
* takes tty_ldiscs_lock to guard against ldisc races
*/
+#if defined(CONFIG_LDISC_AUTOLOAD)
+ #define INITIAL_AUTOLOAD_STATE 1
+#else
+ #define INITIAL_AUTOLOAD_STATE 0
+#endif
+static int tty_ldisc_autoload = INITIAL_AUTOLOAD_STATE;
+
static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc)
{
struct tty_ldisc *ld;
*/
ldops = get_ldops(disc);
if (IS_ERR(ldops)) {
+ if (!capable(CAP_SYS_MODULE) && !tty_ldisc_autoload)
+ return ERR_PTR(-EPERM);
request_module("tty-ldisc-%d", disc);
ldops = get_ldops(disc);
if (IS_ERR(ldops))
tty_ldisc_put(tty->ldisc);
tty->ldisc = NULL;
}
+
+static int zero;
+static int one = 1;
+static struct ctl_table tty_table[] = {
+ {
+ .procname = "ldisc_autoload",
+ .data = &tty_ldisc_autoload,
+ .maxlen = sizeof(tty_ldisc_autoload),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ { }
+};
+
+static struct ctl_table tty_dir_table[] = {
+ {
+ .procname = "tty",
+ .mode = 0555,
+ .child = tty_table,
+ },
+ { }
+};
+
+static struct ctl_table tty_root_table[] = {
+ {
+ .procname = "dev",
+ .mode = 0555,
+ .child = tty_dir_table,
+ },
+ { }
+};
+
+void tty_sysctl_init(void)
+{
+ register_sysctl_table(tty_root_table);
+}