1 /* -*- linux-c -*- --------------------------------------------------------- *
3 * linux/fs/devpts/inode.c
5 * Copyright 1998-2004 H. Peter Anvin -- All Rights Reserved
7 * This file is part of the Linux kernel and is made available under
8 * the terms of the GNU General Public License, version 2, or at your
9 * option, any later version, incorporated herein by reference.
11 * ------------------------------------------------------------------------- */
13 #include <linux/module.h>
14 #include <linux/init.h>
16 #include <linux/sched.h>
17 #include <linux/namei.h>
18 #include <linux/mount.h>
19 #include <linux/tty.h>
20 #include <linux/devpts_fs.h>
21 #include <linux/parser.h>
24 static int devpts_permission(struct inode *inode, int mask, struct nameidata *nd)
28 if (vx_check(inode->i_xid, VX_IDENT))
29 ret = generic_permission(inode, mask, NULL);
33 static struct inode_operations devpts_file_inode_operations = {
34 .permission = devpts_permission,
37 static struct vfsmount *devpts_mnt;
38 static struct dentry *devpts_root;
46 } config = {.mode = 0600};
49 Opt_uid, Opt_gid, Opt_mode,
53 static match_table_t tokens = {
56 {Opt_mode, "mode=%o"},
60 static int devpts_remount(struct super_block *sb, int *flags, char *data)
70 while ((p = strsep(&data, ",")) != NULL) {
71 substring_t args[MAX_OPT_ARGS];
78 token = match_token(p, tokens, args);
81 if (match_int(&args[0], &option))
87 if (match_int(&args[0], &option))
93 if (match_octal(&args[0], &option))
95 config.mode = option & ~S_IFMT;
98 printk(KERN_ERR "devpts: called with bogus options\n");
106 static int devpts_filter(struct dentry *de)
108 return vx_check(de->d_inode->i_xid, VX_IDENT);
111 static int devpts_readdir(struct file * filp, void * dirent, filldir_t filldir)
113 return dcache_readdir_filter(filp, dirent, filldir, devpts_filter);
116 static struct file_operations devpts_dir_operations = {
117 .open = dcache_dir_open,
118 .release = dcache_dir_close,
119 .llseek = dcache_dir_lseek,
120 .read = generic_read_dir,
121 .readdir = devpts_readdir,
124 static struct super_operations devpts_sops = {
125 .statfs = simple_statfs,
126 .remount_fs = devpts_remount,
130 devpts_fill_super(struct super_block *s, void *data, int silent)
132 struct inode * inode;
134 s->s_blocksize = 1024;
135 s->s_blocksize_bits = 10;
136 s->s_magic = DEVPTS_SUPER_MAGIC;
137 s->s_op = &devpts_sops;
140 inode = new_inode(s);
144 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
146 inode->i_uid = inode->i_gid = 0;
147 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
148 inode->i_op = &simple_dir_inode_operations;
149 inode->i_fop = &devpts_dir_operations;
151 inode->i_xid = vx_current_xid();
153 devpts_root = s->s_root = d_alloc_root(inode);
157 printk("devpts: get root dentry failed\n");
163 static int devpts_get_sb(struct file_system_type *fs_type,
164 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
166 return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt);
169 static struct file_system_type devpts_fs_type = {
170 .owner = THIS_MODULE,
172 .get_sb = devpts_get_sb,
173 .kill_sb = kill_anon_super,
177 * The normal naming convention is simply /dev/pts/<number>; this conforms
178 * to the System V naming convention
181 static struct dentry *get_node(int num)
184 struct dentry *root = devpts_root;
185 mutex_lock(&root->d_inode->i_mutex);
186 return lookup_one_len(s, root, sprintf(s, "%d", num));
189 int devpts_pty_new(struct tty_struct *tty)
191 int number = tty->index;
192 struct tty_driver *driver = tty->driver;
193 dev_t device = MKDEV(driver->major, driver->minor_start+number);
194 struct dentry *dentry;
195 struct inode *inode = new_inode(devpts_mnt->mnt_sb);
197 /* We're supposed to be given the slave end of a pty */
198 BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY);
199 BUG_ON(driver->subtype != PTY_TYPE_SLAVE);
204 inode->i_ino = number+2;
205 inode->i_uid = config.setuid ? config.uid : current->fsuid;
206 inode->i_gid = config.setgid ? config.gid : current->fsgid;
207 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
208 init_special_inode(inode, S_IFCHR|config.mode, device);
209 inode->i_xid = vx_current_xid();
210 inode->i_op = &devpts_file_inode_operations;
211 inode->i_private = tty;
213 dentry = get_node(number);
214 if (!IS_ERR(dentry) && !dentry->d_inode)
215 d_instantiate(dentry, inode);
217 mutex_unlock(&devpts_root->d_inode->i_mutex);
222 struct tty_struct *devpts_get_tty(int number)
224 struct dentry *dentry = get_node(number);
225 struct tty_struct *tty;
228 if (!IS_ERR(dentry)) {
230 tty = dentry->d_inode->i_private;
234 mutex_unlock(&devpts_root->d_inode->i_mutex);
239 void devpts_pty_kill(int number)
241 struct dentry *dentry = get_node(number);
243 if (!IS_ERR(dentry)) {
244 struct inode *inode = dentry->d_inode;
252 mutex_unlock(&devpts_root->d_inode->i_mutex);
255 static int __init init_devpts_fs(void)
257 int err = register_filesystem(&devpts_fs_type);
259 devpts_mnt = kern_mount(&devpts_fs_type);
260 if (IS_ERR(devpts_mnt))
261 err = PTR_ERR(devpts_mnt);
266 static void __exit exit_devpts_fs(void)
268 unregister_filesystem(&devpts_fs_type);
272 module_init(init_devpts_fs)
273 module_exit(exit_devpts_fs)
274 MODULE_LICENSE("GPL");