#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/tty.h>
+#include <linux/mutex.h>
+#include <linux/idr.h>
#include <linux/devpts_fs.h>
#include <linux/parser.h>
+#include <linux/fsnotify.h>
+#include <linux/seq_file.h>
#define DEVPTS_SUPER_MAGIC 0x1cd1
+#define DEVPTS_DEFAULT_MODE 0600
+
+extern int pty_limit; /* Config limit on Unix98 ptys */
+static DEFINE_IDA(allocated_ptys);
+static DEFINE_MUTEX(allocated_ptys_lock);
+
static struct vfsmount *devpts_mnt;
static struct dentry *devpts_root;
uid_t uid;
gid_t gid;
umode_t mode;
-} config = {.mode = 0600};
+} config = {.mode = DEVPTS_DEFAULT_MODE};
enum {
Opt_uid, Opt_gid, Opt_mode,
config.setgid = 0;
config.uid = 0;
config.gid = 0;
- config.mode = 0600;
+ config.mode = DEVPTS_DEFAULT_MODE;
while ((p = strsep(&data, ",")) != NULL) {
substring_t args[MAX_OPT_ARGS];
case Opt_mode:
if (match_octal(&args[0], &option))
return -EINVAL;
- config.mode = option & ~S_IFMT;
+ config.mode = option & S_IALLUGO;
break;
default:
printk(KERN_ERR "devpts: called with bogus options\n");
return 0;
}
+static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+ if (config.setuid)
+ seq_printf(seq, ",uid=%u", config.uid);
+ if (config.setgid)
+ seq_printf(seq, ",gid=%u", config.gid);
+ seq_printf(seq, ",mode=%03o", config.mode);
+
+ return 0;
+}
+
static const struct super_operations devpts_sops = {
.statfs = simple_statfs,
.remount_fs = devpts_remount,
+ .show_options = devpts_show_options,
};
static int
return lookup_one_len(s, root, sprintf(s, "%d", num));
}
+int devpts_new_index(void)
+{
+ int index;
+ int ida_ret;
+
+retry:
+ if (!ida_pre_get(&allocated_ptys, GFP_KERNEL)) {
+ return -ENOMEM;
+ }
+
+ mutex_lock(&allocated_ptys_lock);
+ ida_ret = ida_get_new(&allocated_ptys, &index);
+ if (ida_ret < 0) {
+ mutex_unlock(&allocated_ptys_lock);
+ if (ida_ret == -EAGAIN)
+ goto retry;
+ return -EIO;
+ }
+
+ if (index >= pty_limit) {
+ ida_remove(&allocated_ptys, index);
+ mutex_unlock(&allocated_ptys_lock);
+ return -EIO;
+ }
+ mutex_unlock(&allocated_ptys_lock);
+ return index;
+}
+
+void devpts_kill_index(int idx)
+{
+ mutex_lock(&allocated_ptys_lock);
+ ida_remove(&allocated_ptys, idx);
+ mutex_unlock(&allocated_ptys_lock);
+}
+
int devpts_pty_new(struct tty_struct *tty)
{
- int number = tty->index;
+ int number = tty->index; /* tty layer puts index from devpts_new_index() in here */
struct tty_driver *driver = tty->driver;
dev_t device = MKDEV(driver->major, driver->minor_start+number);
struct dentry *dentry;
inode->i_private = tty;
dentry = get_node(number);
- if (!IS_ERR(dentry) && !dentry->d_inode)
+ if (!IS_ERR(dentry) && !dentry->d_inode) {
d_instantiate(dentry, inode);
+ fsnotify_create(devpts_root->d_inode, dentry);
+ }
mutex_unlock(&devpts_root->d_inode->i_mutex);