11da177e4SLinus Torvalds /* -*- linux-c -*- --------------------------------------------------------- * 21da177e4SLinus Torvalds * 31da177e4SLinus Torvalds * linux/fs/devpts/inode.c 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * Copyright 1998-2004 H. Peter Anvin -- All Rights Reserved 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * This file is part of the Linux kernel and is made available under 81da177e4SLinus Torvalds * the terms of the GNU General Public License, version 2, or at your 91da177e4SLinus Torvalds * option, any later version, incorporated herein by reference. 101da177e4SLinus Torvalds * 111da177e4SLinus Torvalds * ------------------------------------------------------------------------- */ 121da177e4SLinus Torvalds 131da177e4SLinus Torvalds #include <linux/module.h> 141da177e4SLinus Torvalds #include <linux/init.h> 151da177e4SLinus Torvalds #include <linux/fs.h> 161da177e4SLinus Torvalds #include <linux/sched.h> 171da177e4SLinus Torvalds #include <linux/namei.h> 181da177e4SLinus Torvalds #include <linux/mount.h> 191da177e4SLinus Torvalds #include <linux/tty.h> 201da177e4SLinus Torvalds #include <linux/devpts_fs.h> 211da177e4SLinus Torvalds #include <linux/xattr.h> 221da177e4SLinus Torvalds 231da177e4SLinus Torvalds #define DEVPTS_SUPER_MAGIC 0x1cd1 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds extern struct xattr_handler devpts_xattr_security_handler; 261da177e4SLinus Torvalds 271da177e4SLinus Torvalds static struct xattr_handler *devpts_xattr_handlers[] = { 281da177e4SLinus Torvalds #ifdef CONFIG_DEVPTS_FS_SECURITY 291da177e4SLinus Torvalds &devpts_xattr_security_handler, 301da177e4SLinus Torvalds #endif 311da177e4SLinus Torvalds NULL 321da177e4SLinus Torvalds }; 331da177e4SLinus Torvalds 341da177e4SLinus Torvalds static struct inode_operations devpts_file_inode_operations = { 351da177e4SLinus Torvalds #ifdef CONFIG_DEVPTS_FS_XATTR 361da177e4SLinus Torvalds .setxattr = generic_setxattr, 371da177e4SLinus Torvalds .getxattr = generic_getxattr, 381da177e4SLinus Torvalds .listxattr = generic_listxattr, 391da177e4SLinus Torvalds .removexattr = generic_removexattr, 401da177e4SLinus Torvalds #endif 411da177e4SLinus Torvalds }; 421da177e4SLinus Torvalds 431da177e4SLinus Torvalds static struct vfsmount *devpts_mnt; 441da177e4SLinus Torvalds static struct dentry *devpts_root; 451da177e4SLinus Torvalds 461da177e4SLinus Torvalds static struct { 471da177e4SLinus Torvalds int setuid; 481da177e4SLinus Torvalds int setgid; 491da177e4SLinus Torvalds uid_t uid; 501da177e4SLinus Torvalds gid_t gid; 511da177e4SLinus Torvalds umode_t mode; 521da177e4SLinus Torvalds } config = {.mode = 0600}; 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds static int devpts_remount(struct super_block *sb, int *flags, char *data) 551da177e4SLinus Torvalds { 561da177e4SLinus Torvalds int setuid = 0; 571da177e4SLinus Torvalds int setgid = 0; 581da177e4SLinus Torvalds uid_t uid = 0; 591da177e4SLinus Torvalds gid_t gid = 0; 601da177e4SLinus Torvalds umode_t mode = 0600; 611da177e4SLinus Torvalds char *this_char; 621da177e4SLinus Torvalds 631da177e4SLinus Torvalds this_char = NULL; 641da177e4SLinus Torvalds while ((this_char = strsep(&data, ",")) != NULL) { 651da177e4SLinus Torvalds int n; 661da177e4SLinus Torvalds char dummy; 671da177e4SLinus Torvalds if (!*this_char) 681da177e4SLinus Torvalds continue; 691da177e4SLinus Torvalds if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) { 701da177e4SLinus Torvalds setuid = 1; 711da177e4SLinus Torvalds uid = n; 721da177e4SLinus Torvalds } else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) { 731da177e4SLinus Torvalds setgid = 1; 741da177e4SLinus Torvalds gid = n; 751da177e4SLinus Torvalds } else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1) 761da177e4SLinus Torvalds mode = n & ~S_IFMT; 771da177e4SLinus Torvalds else { 781da177e4SLinus Torvalds printk("devpts: called with bogus options\n"); 791da177e4SLinus Torvalds return -EINVAL; 801da177e4SLinus Torvalds } 811da177e4SLinus Torvalds } 821da177e4SLinus Torvalds config.setuid = setuid; 831da177e4SLinus Torvalds config.setgid = setgid; 841da177e4SLinus Torvalds config.uid = uid; 851da177e4SLinus Torvalds config.gid = gid; 861da177e4SLinus Torvalds config.mode = mode; 871da177e4SLinus Torvalds 881da177e4SLinus Torvalds return 0; 891da177e4SLinus Torvalds } 901da177e4SLinus Torvalds 911da177e4SLinus Torvalds static struct super_operations devpts_sops = { 921da177e4SLinus Torvalds .statfs = simple_statfs, 931da177e4SLinus Torvalds .remount_fs = devpts_remount, 941da177e4SLinus Torvalds }; 951da177e4SLinus Torvalds 961da177e4SLinus Torvalds static int 971da177e4SLinus Torvalds devpts_fill_super(struct super_block *s, void *data, int silent) 981da177e4SLinus Torvalds { 991da177e4SLinus Torvalds struct inode * inode; 1001da177e4SLinus Torvalds 1011da177e4SLinus Torvalds s->s_blocksize = 1024; 1021da177e4SLinus Torvalds s->s_blocksize_bits = 10; 1031da177e4SLinus Torvalds s->s_magic = DEVPTS_SUPER_MAGIC; 1041da177e4SLinus Torvalds s->s_op = &devpts_sops; 1051da177e4SLinus Torvalds s->s_xattr = devpts_xattr_handlers; 1061da177e4SLinus Torvalds s->s_time_gran = 1; 1071da177e4SLinus Torvalds 1081da177e4SLinus Torvalds inode = new_inode(s); 1091da177e4SLinus Torvalds if (!inode) 1101da177e4SLinus Torvalds goto fail; 1111da177e4SLinus Torvalds inode->i_ino = 1; 1121da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 1131da177e4SLinus Torvalds inode->i_blocks = 0; 1141da177e4SLinus Torvalds inode->i_blksize = 1024; 1151da177e4SLinus Torvalds inode->i_uid = inode->i_gid = 0; 1161da177e4SLinus Torvalds inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; 1171da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 1181da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 1191da177e4SLinus Torvalds inode->i_nlink = 2; 1201da177e4SLinus Torvalds 1211da177e4SLinus Torvalds devpts_root = s->s_root = d_alloc_root(inode); 1221da177e4SLinus Torvalds if (s->s_root) 1231da177e4SLinus Torvalds return 0; 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds printk("devpts: get root dentry failed\n"); 1261da177e4SLinus Torvalds iput(inode); 1271da177e4SLinus Torvalds fail: 1281da177e4SLinus Torvalds return -ENOMEM; 1291da177e4SLinus Torvalds } 1301da177e4SLinus Torvalds 1311da177e4SLinus Torvalds static struct super_block *devpts_get_sb(struct file_system_type *fs_type, 1321da177e4SLinus Torvalds int flags, const char *dev_name, void *data) 1331da177e4SLinus Torvalds { 1341da177e4SLinus Torvalds return get_sb_single(fs_type, flags, data, devpts_fill_super); 1351da177e4SLinus Torvalds } 1361da177e4SLinus Torvalds 1371da177e4SLinus Torvalds static struct file_system_type devpts_fs_type = { 1381da177e4SLinus Torvalds .owner = THIS_MODULE, 1391da177e4SLinus Torvalds .name = "devpts", 1401da177e4SLinus Torvalds .get_sb = devpts_get_sb, 1411da177e4SLinus Torvalds .kill_sb = kill_anon_super, 1421da177e4SLinus Torvalds }; 1431da177e4SLinus Torvalds 1441da177e4SLinus Torvalds /* 1451da177e4SLinus Torvalds * The normal naming convention is simply /dev/pts/<number>; this conforms 1461da177e4SLinus Torvalds * to the System V naming convention 1471da177e4SLinus Torvalds */ 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds static struct dentry *get_node(int num) 1501da177e4SLinus Torvalds { 1511da177e4SLinus Torvalds char s[12]; 1521da177e4SLinus Torvalds struct dentry *root = devpts_root; 1531da177e4SLinus Torvalds down(&root->d_inode->i_sem); 1541da177e4SLinus Torvalds return lookup_one_len(s, root, sprintf(s, "%d", num)); 1551da177e4SLinus Torvalds } 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds int devpts_pty_new(struct tty_struct *tty) 1581da177e4SLinus Torvalds { 1591da177e4SLinus Torvalds int number = tty->index; 1601da177e4SLinus Torvalds struct tty_driver *driver = tty->driver; 1611da177e4SLinus Torvalds dev_t device = MKDEV(driver->major, driver->minor_start+number); 1621da177e4SLinus Torvalds struct dentry *dentry; 1631da177e4SLinus Torvalds struct inode *inode = new_inode(devpts_mnt->mnt_sb); 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds /* We're supposed to be given the slave end of a pty */ 1661da177e4SLinus Torvalds BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY); 1671da177e4SLinus Torvalds BUG_ON(driver->subtype != PTY_TYPE_SLAVE); 1681da177e4SLinus Torvalds 1691da177e4SLinus Torvalds if (!inode) 1701da177e4SLinus Torvalds return -ENOMEM; 1711da177e4SLinus Torvalds 1721da177e4SLinus Torvalds inode->i_ino = number+2; 1731da177e4SLinus Torvalds inode->i_blksize = 1024; 1741da177e4SLinus Torvalds inode->i_uid = config.setuid ? config.uid : current->fsuid; 1751da177e4SLinus Torvalds inode->i_gid = config.setgid ? config.gid : current->fsgid; 1761da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 1771da177e4SLinus Torvalds init_special_inode(inode, S_IFCHR|config.mode, device); 1781da177e4SLinus Torvalds inode->i_op = &devpts_file_inode_operations; 1791da177e4SLinus Torvalds inode->u.generic_ip = tty; 1801da177e4SLinus Torvalds 1811da177e4SLinus Torvalds dentry = get_node(number); 1821da177e4SLinus Torvalds if (!IS_ERR(dentry) && !dentry->d_inode) 1831da177e4SLinus Torvalds d_instantiate(dentry, inode); 1841da177e4SLinus Torvalds 1851da177e4SLinus Torvalds up(&devpts_root->d_inode->i_sem); 1861da177e4SLinus Torvalds 1871da177e4SLinus Torvalds return 0; 1881da177e4SLinus Torvalds } 1891da177e4SLinus Torvalds 1901da177e4SLinus Torvalds struct tty_struct *devpts_get_tty(int number) 1911da177e4SLinus Torvalds { 1921da177e4SLinus Torvalds struct dentry *dentry = get_node(number); 1931da177e4SLinus Torvalds struct tty_struct *tty; 1941da177e4SLinus Torvalds 1951da177e4SLinus Torvalds tty = NULL; 1961da177e4SLinus Torvalds if (!IS_ERR(dentry)) { 1971da177e4SLinus Torvalds if (dentry->d_inode) 1981da177e4SLinus Torvalds tty = dentry->d_inode->u.generic_ip; 1991da177e4SLinus Torvalds dput(dentry); 2001da177e4SLinus Torvalds } 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds up(&devpts_root->d_inode->i_sem); 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvalds return tty; 2051da177e4SLinus Torvalds } 2061da177e4SLinus Torvalds 2071da177e4SLinus Torvalds void devpts_pty_kill(int number) 2081da177e4SLinus Torvalds { 2091da177e4SLinus Torvalds struct dentry *dentry = get_node(number); 2101da177e4SLinus Torvalds 2111da177e4SLinus Torvalds if (!IS_ERR(dentry)) { 2121da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 2131da177e4SLinus Torvalds if (inode) { 2141da177e4SLinus Torvalds inode->i_nlink--; 2151da177e4SLinus Torvalds d_delete(dentry); 2161da177e4SLinus Torvalds dput(dentry); 2171da177e4SLinus Torvalds } 2181da177e4SLinus Torvalds dput(dentry); 2191da177e4SLinus Torvalds } 2201da177e4SLinus Torvalds up(&devpts_root->d_inode->i_sem); 2211da177e4SLinus Torvalds } 2221da177e4SLinus Torvalds 2231da177e4SLinus Torvalds static int __init init_devpts_fs(void) 2241da177e4SLinus Torvalds { 2251da177e4SLinus Torvalds int err = register_filesystem(&devpts_fs_type); 2261da177e4SLinus Torvalds if (!err) { 2271da177e4SLinus Torvalds devpts_mnt = kern_mount(&devpts_fs_type); 2281da177e4SLinus Torvalds if (IS_ERR(devpts_mnt)) 2291da177e4SLinus Torvalds err = PTR_ERR(devpts_mnt); 2301da177e4SLinus Torvalds } 2311da177e4SLinus Torvalds return err; 2321da177e4SLinus Torvalds } 2331da177e4SLinus Torvalds 2341da177e4SLinus Torvalds static void __exit exit_devpts_fs(void) 2351da177e4SLinus Torvalds { 2361da177e4SLinus Torvalds unregister_filesystem(&devpts_fs_type); 2371da177e4SLinus Torvalds mntput(devpts_mnt); 2381da177e4SLinus Torvalds } 2391da177e4SLinus Torvalds 2401da177e4SLinus Torvalds module_init(init_devpts_fs) 2411da177e4SLinus Torvalds module_exit(exit_devpts_fs) 2421da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 243