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/vinline.h>
24 #define DEVPTS_SUPER_MAGIC 0x1cd1
26 static struct vfsmount *devpts_mnt;
27 static struct dentry *devpts_root;
35 } config = {.mode = 0600};
37 static int devpts_remount(struct super_block *sb, int *flags, char *data)
47 while ((this_char = strsep(&data, ",")) != NULL) {
52 if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) {
55 } else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) {
58 } else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1)
61 printk("devpts: called with bogus options\n");
65 config.setuid = setuid;
66 config.setgid = setgid;
74 static struct super_operations devpts_sops = {
75 .statfs = simple_statfs,
76 .remount_fs = devpts_remount,
80 devpts_fill_super(struct super_block *s, void *data, int silent)
84 s->s_blocksize = 1024;
85 s->s_blocksize_bits = 10;
86 s->s_magic = DEVPTS_SUPER_MAGIC;
87 s->s_op = &devpts_sops;
93 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
95 inode->i_blksize = 1024;
96 inode->i_uid = inode->i_gid = 0;
97 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
98 inode->i_op = &simple_dir_inode_operations;
99 inode->i_fop = &simple_dir_operations;
102 devpts_root = s->s_root = d_alloc_root(inode);
106 printk("devpts: get root dentry failed\n");
112 static struct super_block *devpts_get_sb(struct file_system_type *fs_type,
113 int flags, const char *dev_name, void *data)
115 return get_sb_single(fs_type, flags, data, devpts_fill_super);
118 static struct file_system_type devpts_fs_type = {
119 .owner = THIS_MODULE,
121 .get_sb = devpts_get_sb,
122 .kill_sb = kill_anon_super,
126 * The normal naming convention is simply /dev/pts/<number>; this conforms
127 * to the System V naming convention
130 static struct dentry *get_node(int num)
133 struct dentry *root = devpts_root;
134 down(&root->d_inode->i_sem);
135 return lookup_one_len(s, root, sprintf(s, "%d", num));
138 static int devpts_permission(struct inode *inode, int mask, struct nameidata *nd)
142 if (vx_check(inode->i_xid, VX_IDENT))
143 ret = vfs_permission(inode, mask);
147 static struct inode_operations devpts_file_inode_operations = {
148 .setxattr = devpts_setxattr,
149 .getxattr = devpts_getxattr,
150 .listxattr = devpts_listxattr,
151 .removexattr = devpts_removexattr,
152 .permission = devpts_permission,
155 int devpts_pty_new(struct tty_struct *tty)
157 int number = tty->index;
158 struct tty_driver *driver = tty->driver;
159 dev_t device = MKDEV(driver->major, driver->minor_start+number);
160 struct dentry *dentry;
161 struct inode *inode = new_inode(devpts_mnt->mnt_sb);
163 /* We're supposed to be given the slave end of a pty */
164 BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY);
165 BUG_ON(driver->subtype != PTY_TYPE_SLAVE);
170 inode->i_ino = number+2;
171 inode->i_blksize = 1024;
172 inode->i_uid = config.setuid ? config.uid : current->fsuid;
173 inode->i_gid = config.setgid ? config.gid : current->fsgid;
174 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
175 init_special_inode(inode, S_IFCHR|config.mode, device);
176 inode->i_xid = vx_current_xid();
177 inode->i_op = &devpts_file_inode_operations;
178 inode->u.generic_ip = tty;
180 dentry = get_node(number);
181 if (!IS_ERR(dentry) && !dentry->d_inode)
182 d_instantiate(dentry, inode);
184 up(&devpts_root->d_inode->i_sem);
189 struct tty_struct *devpts_get_tty(int number)
191 struct dentry *dentry = get_node(number);
192 struct tty_struct *tty;
194 tty = (IS_ERR(dentry) || !dentry->d_inode) ? NULL :
195 dentry->d_inode->u.generic_ip;
197 up(&devpts_root->d_inode->i_sem);
202 void devpts_pty_kill(int number)
204 struct dentry *dentry = get_node(number);
206 if (!IS_ERR(dentry)) {
207 struct inode *inode = dentry->d_inode;
215 up(&devpts_root->d_inode->i_sem);
218 static int __init init_devpts_fs(void)
220 int err = init_devpts_xattr();
223 err = register_filesystem(&devpts_fs_type);
225 devpts_mnt = kern_mount(&devpts_fs_type);
226 if (IS_ERR(devpts_mnt))
227 err = PTR_ERR(devpts_mnt);
232 static void __exit exit_devpts_fs(void)
234 unregister_filesystem(&devpts_fs_type);
239 module_init(init_devpts_fs)
240 module_exit(exit_devpts_fs)
241 MODULE_LICENSE("GPL");