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> 217a673c6bSDomen Puncer #include <linux/parser.h> 223972b7f6SFlorin Malita #include <linux/fsnotify.h> 231da177e4SLinus Torvalds 241da177e4SLinus Torvalds #define DEVPTS_SUPER_MAGIC 0x1cd1 251da177e4SLinus Torvalds 261da177e4SLinus Torvalds static struct vfsmount *devpts_mnt; 271da177e4SLinus Torvalds static struct dentry *devpts_root; 281da177e4SLinus Torvalds 291da177e4SLinus Torvalds static struct { 301da177e4SLinus Torvalds int setuid; 311da177e4SLinus Torvalds int setgid; 321da177e4SLinus Torvalds uid_t uid; 331da177e4SLinus Torvalds gid_t gid; 341da177e4SLinus Torvalds umode_t mode; 351da177e4SLinus Torvalds } config = {.mode = 0600}; 361da177e4SLinus Torvalds 377a673c6bSDomen Puncer enum { 387a673c6bSDomen Puncer Opt_uid, Opt_gid, Opt_mode, 397a673c6bSDomen Puncer Opt_err 407a673c6bSDomen Puncer }; 417a673c6bSDomen Puncer 427a673c6bSDomen Puncer static match_table_t tokens = { 437a673c6bSDomen Puncer {Opt_uid, "uid=%u"}, 447a673c6bSDomen Puncer {Opt_gid, "gid=%u"}, 457a673c6bSDomen Puncer {Opt_mode, "mode=%o"}, 467a673c6bSDomen Puncer {Opt_err, NULL} 477a673c6bSDomen Puncer }; 487a673c6bSDomen Puncer 491da177e4SLinus Torvalds static int devpts_remount(struct super_block *sb, int *flags, char *data) 501da177e4SLinus Torvalds { 517a673c6bSDomen Puncer char *p; 521da177e4SLinus Torvalds 537a673c6bSDomen Puncer config.setuid = 0; 547a673c6bSDomen Puncer config.setgid = 0; 557a673c6bSDomen Puncer config.uid = 0; 567a673c6bSDomen Puncer config.gid = 0; 577a673c6bSDomen Puncer config.mode = 0600; 587a673c6bSDomen Puncer 597a673c6bSDomen Puncer while ((p = strsep(&data, ",")) != NULL) { 607a673c6bSDomen Puncer substring_t args[MAX_OPT_ARGS]; 617a673c6bSDomen Puncer int token; 627a673c6bSDomen Puncer int option; 637a673c6bSDomen Puncer 647a673c6bSDomen Puncer if (!*p) 651da177e4SLinus Torvalds continue; 667a673c6bSDomen Puncer 677a673c6bSDomen Puncer token = match_token(p, tokens, args); 687a673c6bSDomen Puncer switch (token) { 697a673c6bSDomen Puncer case Opt_uid: 707a673c6bSDomen Puncer if (match_int(&args[0], &option)) 717a673c6bSDomen Puncer return -EINVAL; 727a673c6bSDomen Puncer config.uid = option; 737a673c6bSDomen Puncer config.setuid = 1; 747a673c6bSDomen Puncer break; 757a673c6bSDomen Puncer case Opt_gid: 767a673c6bSDomen Puncer if (match_int(&args[0], &option)) 777a673c6bSDomen Puncer return -EINVAL; 787a673c6bSDomen Puncer config.gid = option; 797a673c6bSDomen Puncer config.setgid = 1; 807a673c6bSDomen Puncer break; 817a673c6bSDomen Puncer case Opt_mode: 827a673c6bSDomen Puncer if (match_octal(&args[0], &option)) 837a673c6bSDomen Puncer return -EINVAL; 847a673c6bSDomen Puncer config.mode = option & ~S_IFMT; 857a673c6bSDomen Puncer break; 867a673c6bSDomen Puncer default: 877a673c6bSDomen Puncer printk(KERN_ERR "devpts: called with bogus options\n"); 881da177e4SLinus Torvalds return -EINVAL; 891da177e4SLinus Torvalds } 901da177e4SLinus Torvalds } 911da177e4SLinus Torvalds 921da177e4SLinus Torvalds return 0; 931da177e4SLinus Torvalds } 941da177e4SLinus Torvalds 95ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations devpts_sops = { 961da177e4SLinus Torvalds .statfs = simple_statfs, 971da177e4SLinus Torvalds .remount_fs = devpts_remount, 981da177e4SLinus Torvalds }; 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds static int 1011da177e4SLinus Torvalds devpts_fill_super(struct super_block *s, void *data, int silent) 1021da177e4SLinus Torvalds { 1031da177e4SLinus Torvalds struct inode * inode; 1041da177e4SLinus Torvalds 1051da177e4SLinus Torvalds s->s_blocksize = 1024; 1061da177e4SLinus Torvalds s->s_blocksize_bits = 10; 1071da177e4SLinus Torvalds s->s_magic = DEVPTS_SUPER_MAGIC; 1081da177e4SLinus Torvalds s->s_op = &devpts_sops; 1091da177e4SLinus Torvalds s->s_time_gran = 1; 1101da177e4SLinus Torvalds 1111da177e4SLinus Torvalds inode = new_inode(s); 1121da177e4SLinus Torvalds if (!inode) 1131da177e4SLinus Torvalds goto fail; 1141da177e4SLinus Torvalds inode->i_ino = 1; 1151da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 1161da177e4SLinus Torvalds inode->i_blocks = 0; 1171da177e4SLinus Torvalds inode->i_uid = inode->i_gid = 0; 1181da177e4SLinus Torvalds inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; 1191da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 1201da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 1211da177e4SLinus Torvalds inode->i_nlink = 2; 1221da177e4SLinus Torvalds 1231da177e4SLinus Torvalds devpts_root = s->s_root = d_alloc_root(inode); 1241da177e4SLinus Torvalds if (s->s_root) 1251da177e4SLinus Torvalds return 0; 1261da177e4SLinus Torvalds 1271da177e4SLinus Torvalds printk("devpts: get root dentry failed\n"); 1281da177e4SLinus Torvalds iput(inode); 1291da177e4SLinus Torvalds fail: 1301da177e4SLinus Torvalds return -ENOMEM; 1311da177e4SLinus Torvalds } 1321da177e4SLinus Torvalds 133454e2398SDavid Howells static int devpts_get_sb(struct file_system_type *fs_type, 134454e2398SDavid Howells int flags, const char *dev_name, void *data, struct vfsmount *mnt) 1351da177e4SLinus Torvalds { 136454e2398SDavid Howells return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt); 1371da177e4SLinus Torvalds } 1381da177e4SLinus Torvalds 1391da177e4SLinus Torvalds static struct file_system_type devpts_fs_type = { 1401da177e4SLinus Torvalds .owner = THIS_MODULE, 1411da177e4SLinus Torvalds .name = "devpts", 1421da177e4SLinus Torvalds .get_sb = devpts_get_sb, 1431da177e4SLinus Torvalds .kill_sb = kill_anon_super, 1441da177e4SLinus Torvalds }; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds /* 1471da177e4SLinus Torvalds * The normal naming convention is simply /dev/pts/<number>; this conforms 1481da177e4SLinus Torvalds * to the System V naming convention 1491da177e4SLinus Torvalds */ 1501da177e4SLinus Torvalds 1511da177e4SLinus Torvalds static struct dentry *get_node(int num) 1521da177e4SLinus Torvalds { 1531da177e4SLinus Torvalds char s[12]; 1541da177e4SLinus Torvalds struct dentry *root = devpts_root; 1551b1dcc1bSJes Sorensen mutex_lock(&root->d_inode->i_mutex); 1561da177e4SLinus Torvalds return lookup_one_len(s, root, sprintf(s, "%d", num)); 1571da177e4SLinus Torvalds } 1581da177e4SLinus Torvalds 1591da177e4SLinus Torvalds int devpts_pty_new(struct tty_struct *tty) 1601da177e4SLinus Torvalds { 1611da177e4SLinus Torvalds int number = tty->index; 1621da177e4SLinus Torvalds struct tty_driver *driver = tty->driver; 1631da177e4SLinus Torvalds dev_t device = MKDEV(driver->major, driver->minor_start+number); 1641da177e4SLinus Torvalds struct dentry *dentry; 1651da177e4SLinus Torvalds struct inode *inode = new_inode(devpts_mnt->mnt_sb); 1661da177e4SLinus Torvalds 1671da177e4SLinus Torvalds /* We're supposed to be given the slave end of a pty */ 1681da177e4SLinus Torvalds BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY); 1691da177e4SLinus Torvalds BUG_ON(driver->subtype != PTY_TYPE_SLAVE); 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds if (!inode) 1721da177e4SLinus Torvalds return -ENOMEM; 1731da177e4SLinus Torvalds 1741da177e4SLinus Torvalds inode->i_ino = number+2; 1751da177e4SLinus Torvalds inode->i_uid = config.setuid ? config.uid : current->fsuid; 1761da177e4SLinus Torvalds inode->i_gid = config.setgid ? config.gid : current->fsgid; 1771da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 1781da177e4SLinus Torvalds init_special_inode(inode, S_IFCHR|config.mode, device); 1798e18e294STheodore Ts'o inode->i_private = tty; 1801da177e4SLinus Torvalds 1811da177e4SLinus Torvalds dentry = get_node(number); 1823972b7f6SFlorin Malita if (!IS_ERR(dentry) && !dentry->d_inode) { 1831da177e4SLinus Torvalds d_instantiate(dentry, inode); 1843972b7f6SFlorin Malita fsnotify_create(devpts_root->d_inode, dentry); 1853972b7f6SFlorin Malita } 1861da177e4SLinus Torvalds 1871b1dcc1bSJes Sorensen mutex_unlock(&devpts_root->d_inode->i_mutex); 1881da177e4SLinus Torvalds 1891da177e4SLinus Torvalds return 0; 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds struct tty_struct *devpts_get_tty(int number) 1931da177e4SLinus Torvalds { 1941da177e4SLinus Torvalds struct dentry *dentry = get_node(number); 1951da177e4SLinus Torvalds struct tty_struct *tty; 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds tty = NULL; 1981da177e4SLinus Torvalds if (!IS_ERR(dentry)) { 1991da177e4SLinus Torvalds if (dentry->d_inode) 2008e18e294STheodore Ts'o tty = dentry->d_inode->i_private; 2011da177e4SLinus Torvalds dput(dentry); 2021da177e4SLinus Torvalds } 2031da177e4SLinus Torvalds 2041b1dcc1bSJes Sorensen mutex_unlock(&devpts_root->d_inode->i_mutex); 2051da177e4SLinus Torvalds 2061da177e4SLinus Torvalds return tty; 2071da177e4SLinus Torvalds } 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvalds void devpts_pty_kill(int number) 2101da177e4SLinus Torvalds { 2111da177e4SLinus Torvalds struct dentry *dentry = get_node(number); 2121da177e4SLinus Torvalds 2131da177e4SLinus Torvalds if (!IS_ERR(dentry)) { 2141da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 2151da177e4SLinus Torvalds if (inode) { 2161da177e4SLinus Torvalds inode->i_nlink--; 2171da177e4SLinus Torvalds d_delete(dentry); 2181da177e4SLinus Torvalds dput(dentry); 2191da177e4SLinus Torvalds } 2201da177e4SLinus Torvalds dput(dentry); 2211da177e4SLinus Torvalds } 2221b1dcc1bSJes Sorensen mutex_unlock(&devpts_root->d_inode->i_mutex); 2231da177e4SLinus Torvalds } 2241da177e4SLinus Torvalds 2251da177e4SLinus Torvalds static int __init init_devpts_fs(void) 2261da177e4SLinus Torvalds { 2271da177e4SLinus Torvalds int err = register_filesystem(&devpts_fs_type); 2281da177e4SLinus Torvalds if (!err) { 2291da177e4SLinus Torvalds devpts_mnt = kern_mount(&devpts_fs_type); 2301da177e4SLinus Torvalds if (IS_ERR(devpts_mnt)) 2311da177e4SLinus Torvalds err = PTR_ERR(devpts_mnt); 2321da177e4SLinus Torvalds } 2331da177e4SLinus Torvalds return err; 2341da177e4SLinus Torvalds } 2351da177e4SLinus Torvalds 2361da177e4SLinus Torvalds static void __exit exit_devpts_fs(void) 2371da177e4SLinus Torvalds { 2381da177e4SLinus Torvalds unregister_filesystem(&devpts_fs_type); 2391da177e4SLinus Torvalds mntput(devpts_mnt); 2401da177e4SLinus Torvalds } 2411da177e4SLinus Torvalds 2421da177e4SLinus Torvalds module_init(init_devpts_fs) 2431da177e4SLinus Torvalds module_exit(exit_devpts_fs) 2441da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 245