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> 20718a9163SSukadev Bhattiprolu #include <linux/mutex.h> 21718a9163SSukadev Bhattiprolu #include <linux/idr.h> 221da177e4SLinus Torvalds #include <linux/devpts_fs.h> 237a673c6bSDomen Puncer #include <linux/parser.h> 243972b7f6SFlorin Malita #include <linux/fsnotify.h> 25b87a267eSMiklos Szeredi #include <linux/seq_file.h> 261da177e4SLinus Torvalds 271da177e4SLinus Torvalds #define DEVPTS_SUPER_MAGIC 0x1cd1 281da177e4SLinus Torvalds 29b87a267eSMiklos Szeredi #define DEVPTS_DEFAULT_MODE 0600 301f8f1e29SSukadev Bhattiprolu /* 311f8f1e29SSukadev Bhattiprolu * ptmx is a new node in /dev/pts and will be unused in legacy (single- 321f8f1e29SSukadev Bhattiprolu * instance) mode. To prevent surprises in user space, set permissions of 331f8f1e29SSukadev Bhattiprolu * ptmx to 0. Use 'chmod' or remount with '-o ptmxmode' to set meaningful 341f8f1e29SSukadev Bhattiprolu * permissions. 351f8f1e29SSukadev Bhattiprolu */ 361f8f1e29SSukadev Bhattiprolu #define DEVPTS_DEFAULT_PTMX_MODE 0000 37527b3e47SSukadev Bhattiprolu #define PTMX_MINOR 2 38b87a267eSMiklos Szeredi 39718a9163SSukadev Bhattiprolu extern int pty_limit; /* Config limit on Unix98 ptys */ 40718a9163SSukadev Bhattiprolu static DEFINE_MUTEX(allocated_ptys_lock); 41718a9163SSukadev Bhattiprolu 421da177e4SLinus Torvalds static struct vfsmount *devpts_mnt; 431da177e4SLinus Torvalds 4431af0abbSSukadev Bhattiprolu struct pts_mount_opts { 451da177e4SLinus Torvalds int setuid; 461da177e4SLinus Torvalds int setgid; 471da177e4SLinus Torvalds uid_t uid; 481da177e4SLinus Torvalds gid_t gid; 491da177e4SLinus Torvalds umode_t mode; 501f8f1e29SSukadev Bhattiprolu umode_t ptmxmode; 512a1b2dc0SSukadev Bhattiprolu int newinstance; 5231af0abbSSukadev Bhattiprolu }; 531da177e4SLinus Torvalds 547a673c6bSDomen Puncer enum { 552a1b2dc0SSukadev Bhattiprolu Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance, 567a673c6bSDomen Puncer Opt_err 577a673c6bSDomen Puncer }; 587a673c6bSDomen Puncer 59a447c093SSteven Whitehouse static const match_table_t tokens = { 607a673c6bSDomen Puncer {Opt_uid, "uid=%u"}, 617a673c6bSDomen Puncer {Opt_gid, "gid=%u"}, 627a673c6bSDomen Puncer {Opt_mode, "mode=%o"}, 631f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 641f8f1e29SSukadev Bhattiprolu {Opt_ptmxmode, "ptmxmode=%o"}, 652a1b2dc0SSukadev Bhattiprolu {Opt_newinstance, "newinstance"}, 661f8f1e29SSukadev Bhattiprolu #endif 677a673c6bSDomen Puncer {Opt_err, NULL} 687a673c6bSDomen Puncer }; 697a673c6bSDomen Puncer 70e76b7c01SSukadev Bhattiprolu struct pts_fs_info { 71e76b7c01SSukadev Bhattiprolu struct ida allocated_ptys; 7231af0abbSSukadev Bhattiprolu struct pts_mount_opts mount_opts; 731f8f1e29SSukadev Bhattiprolu struct dentry *ptmx_dentry; 74e76b7c01SSukadev Bhattiprolu }; 75e76b7c01SSukadev Bhattiprolu 76e76b7c01SSukadev Bhattiprolu static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb) 77e76b7c01SSukadev Bhattiprolu { 78e76b7c01SSukadev Bhattiprolu return sb->s_fs_info; 79e76b7c01SSukadev Bhattiprolu } 80e76b7c01SSukadev Bhattiprolu 8159e55e6cSSukadev Bhattiprolu static inline struct super_block *pts_sb_from_inode(struct inode *inode) 8259e55e6cSSukadev Bhattiprolu { 832a1b2dc0SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 8459e55e6cSSukadev Bhattiprolu if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) 8559e55e6cSSukadev Bhattiprolu return inode->i_sb; 862a1b2dc0SSukadev Bhattiprolu #endif 8759e55e6cSSukadev Bhattiprolu return devpts_mnt->mnt_sb; 8859e55e6cSSukadev Bhattiprolu } 8959e55e6cSSukadev Bhattiprolu 902a1b2dc0SSukadev Bhattiprolu #define PARSE_MOUNT 0 912a1b2dc0SSukadev Bhattiprolu #define PARSE_REMOUNT 1 922a1b2dc0SSukadev Bhattiprolu 932a1b2dc0SSukadev Bhattiprolu static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) 941da177e4SLinus Torvalds { 957a673c6bSDomen Puncer char *p; 961da177e4SLinus Torvalds 9731af0abbSSukadev Bhattiprolu opts->setuid = 0; 9831af0abbSSukadev Bhattiprolu opts->setgid = 0; 9931af0abbSSukadev Bhattiprolu opts->uid = 0; 10031af0abbSSukadev Bhattiprolu opts->gid = 0; 10131af0abbSSukadev Bhattiprolu opts->mode = DEVPTS_DEFAULT_MODE; 1021f8f1e29SSukadev Bhattiprolu opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; 1037a673c6bSDomen Puncer 1042a1b2dc0SSukadev Bhattiprolu /* newinstance makes sense only on initial mount */ 1052a1b2dc0SSukadev Bhattiprolu if (op == PARSE_MOUNT) 1062a1b2dc0SSukadev Bhattiprolu opts->newinstance = 0; 1072a1b2dc0SSukadev Bhattiprolu 1087a673c6bSDomen Puncer while ((p = strsep(&data, ",")) != NULL) { 1097a673c6bSDomen Puncer substring_t args[MAX_OPT_ARGS]; 1107a673c6bSDomen Puncer int token; 1117a673c6bSDomen Puncer int option; 1127a673c6bSDomen Puncer 1137a673c6bSDomen Puncer if (!*p) 1141da177e4SLinus Torvalds continue; 1157a673c6bSDomen Puncer 1167a673c6bSDomen Puncer token = match_token(p, tokens, args); 1177a673c6bSDomen Puncer switch (token) { 1187a673c6bSDomen Puncer case Opt_uid: 1197a673c6bSDomen Puncer if (match_int(&args[0], &option)) 1207a673c6bSDomen Puncer return -EINVAL; 12131af0abbSSukadev Bhattiprolu opts->uid = option; 12231af0abbSSukadev Bhattiprolu opts->setuid = 1; 1237a673c6bSDomen Puncer break; 1247a673c6bSDomen Puncer case Opt_gid: 1257a673c6bSDomen Puncer if (match_int(&args[0], &option)) 1267a673c6bSDomen Puncer return -EINVAL; 12731af0abbSSukadev Bhattiprolu opts->gid = option; 12831af0abbSSukadev Bhattiprolu opts->setgid = 1; 1297a673c6bSDomen Puncer break; 1307a673c6bSDomen Puncer case Opt_mode: 1317a673c6bSDomen Puncer if (match_octal(&args[0], &option)) 1327a673c6bSDomen Puncer return -EINVAL; 13331af0abbSSukadev Bhattiprolu opts->mode = option & S_IALLUGO; 1347a673c6bSDomen Puncer break; 1351f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 1361f8f1e29SSukadev Bhattiprolu case Opt_ptmxmode: 1371f8f1e29SSukadev Bhattiprolu if (match_octal(&args[0], &option)) 1381f8f1e29SSukadev Bhattiprolu return -EINVAL; 1391f8f1e29SSukadev Bhattiprolu opts->ptmxmode = option & S_IALLUGO; 1401f8f1e29SSukadev Bhattiprolu break; 1412a1b2dc0SSukadev Bhattiprolu case Opt_newinstance: 1422a1b2dc0SSukadev Bhattiprolu /* newinstance makes sense only on initial mount */ 1432a1b2dc0SSukadev Bhattiprolu if (op == PARSE_MOUNT) 1442a1b2dc0SSukadev Bhattiprolu opts->newinstance = 1; 1452a1b2dc0SSukadev Bhattiprolu break; 1461f8f1e29SSukadev Bhattiprolu #endif 1477a673c6bSDomen Puncer default: 1487a673c6bSDomen Puncer printk(KERN_ERR "devpts: called with bogus options\n"); 1491da177e4SLinus Torvalds return -EINVAL; 1501da177e4SLinus Torvalds } 1511da177e4SLinus Torvalds } 1521da177e4SLinus Torvalds 1531da177e4SLinus Torvalds return 0; 1541da177e4SLinus Torvalds } 1551da177e4SLinus Torvalds 1561f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 1571f8f1e29SSukadev Bhattiprolu static int mknod_ptmx(struct super_block *sb) 15853af8ee4SSukadev Bhattiprolu { 1591f8f1e29SSukadev Bhattiprolu int mode; 1601f8f1e29SSukadev Bhattiprolu int rc = -ENOMEM; 1611f8f1e29SSukadev Bhattiprolu struct dentry *dentry; 1621f8f1e29SSukadev Bhattiprolu struct inode *inode; 1631f8f1e29SSukadev Bhattiprolu struct dentry *root = sb->s_root; 16453af8ee4SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 16553af8ee4SSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 16653af8ee4SSukadev Bhattiprolu 1671f8f1e29SSukadev Bhattiprolu mutex_lock(&root->d_inode->i_mutex); 1681f8f1e29SSukadev Bhattiprolu 1691f8f1e29SSukadev Bhattiprolu /* If we have already created ptmx node, return */ 1701f8f1e29SSukadev Bhattiprolu if (fsi->ptmx_dentry) { 1711f8f1e29SSukadev Bhattiprolu rc = 0; 1721f8f1e29SSukadev Bhattiprolu goto out; 1731f8f1e29SSukadev Bhattiprolu } 1741f8f1e29SSukadev Bhattiprolu 1751f8f1e29SSukadev Bhattiprolu dentry = d_alloc_name(root, "ptmx"); 1761f8f1e29SSukadev Bhattiprolu if (!dentry) { 1771f8f1e29SSukadev Bhattiprolu printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n"); 1781f8f1e29SSukadev Bhattiprolu goto out; 1791f8f1e29SSukadev Bhattiprolu } 1801f8f1e29SSukadev Bhattiprolu 1811f8f1e29SSukadev Bhattiprolu /* 1821f8f1e29SSukadev Bhattiprolu * Create a new 'ptmx' node in this mount of devpts. 1831f8f1e29SSukadev Bhattiprolu */ 1841f8f1e29SSukadev Bhattiprolu inode = new_inode(sb); 1851f8f1e29SSukadev Bhattiprolu if (!inode) { 1861f8f1e29SSukadev Bhattiprolu printk(KERN_ERR "Unable to alloc inode for ptmx node\n"); 1871f8f1e29SSukadev Bhattiprolu dput(dentry); 1881f8f1e29SSukadev Bhattiprolu goto out; 1891f8f1e29SSukadev Bhattiprolu } 1901f8f1e29SSukadev Bhattiprolu 1911f8f1e29SSukadev Bhattiprolu inode->i_ino = 2; 1921f8f1e29SSukadev Bhattiprolu inode->i_uid = inode->i_gid = 0; 1931f8f1e29SSukadev Bhattiprolu inode->i_blocks = 0; 1941f8f1e29SSukadev Bhattiprolu inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 1951f8f1e29SSukadev Bhattiprolu 1961f8f1e29SSukadev Bhattiprolu mode = S_IFCHR|opts->ptmxmode; 1971f8f1e29SSukadev Bhattiprolu init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2)); 1981f8f1e29SSukadev Bhattiprolu 1991f8f1e29SSukadev Bhattiprolu d_add(dentry, inode); 2001f8f1e29SSukadev Bhattiprolu 2011f8f1e29SSukadev Bhattiprolu fsi->ptmx_dentry = dentry; 2021f8f1e29SSukadev Bhattiprolu rc = 0; 2031f8f1e29SSukadev Bhattiprolu 2041f8f1e29SSukadev Bhattiprolu printk(KERN_DEBUG "Created ptmx node in devpts ino %lu\n", 2051f8f1e29SSukadev Bhattiprolu inode->i_ino); 2061f8f1e29SSukadev Bhattiprolu out: 2071f8f1e29SSukadev Bhattiprolu mutex_unlock(&root->d_inode->i_mutex); 2081f8f1e29SSukadev Bhattiprolu return rc; 2091f8f1e29SSukadev Bhattiprolu } 2101f8f1e29SSukadev Bhattiprolu 2111f8f1e29SSukadev Bhattiprolu static void update_ptmx_mode(struct pts_fs_info *fsi) 2121f8f1e29SSukadev Bhattiprolu { 2131f8f1e29SSukadev Bhattiprolu struct inode *inode; 2141f8f1e29SSukadev Bhattiprolu if (fsi->ptmx_dentry) { 2151f8f1e29SSukadev Bhattiprolu inode = fsi->ptmx_dentry->d_inode; 2161f8f1e29SSukadev Bhattiprolu inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode; 2171f8f1e29SSukadev Bhattiprolu } 2181f8f1e29SSukadev Bhattiprolu } 2191f8f1e29SSukadev Bhattiprolu #else 2201f8f1e29SSukadev Bhattiprolu static inline void update_ptmx_mode(struct pts_fs_info *fsi) 2211f8f1e29SSukadev Bhattiprolu { 2221f8f1e29SSukadev Bhattiprolu return; 2231f8f1e29SSukadev Bhattiprolu } 2241f8f1e29SSukadev Bhattiprolu #endif 2251f8f1e29SSukadev Bhattiprolu 2261f8f1e29SSukadev Bhattiprolu static int devpts_remount(struct super_block *sb, int *flags, char *data) 2271f8f1e29SSukadev Bhattiprolu { 2281f8f1e29SSukadev Bhattiprolu int err; 2291f8f1e29SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 2301f8f1e29SSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 2311f8f1e29SSukadev Bhattiprolu 2322a1b2dc0SSukadev Bhattiprolu err = parse_mount_options(data, PARSE_REMOUNT, opts); 2331f8f1e29SSukadev Bhattiprolu 2341f8f1e29SSukadev Bhattiprolu /* 2351f8f1e29SSukadev Bhattiprolu * parse_mount_options() restores options to default values 2361f8f1e29SSukadev Bhattiprolu * before parsing and may have changed ptmxmode. So, update the 2371f8f1e29SSukadev Bhattiprolu * mode in the inode too. Bogus options don't fail the remount, 2381f8f1e29SSukadev Bhattiprolu * so do this even on error return. 2391f8f1e29SSukadev Bhattiprolu */ 2401f8f1e29SSukadev Bhattiprolu update_ptmx_mode(fsi); 2411f8f1e29SSukadev Bhattiprolu 2421f8f1e29SSukadev Bhattiprolu return err; 24353af8ee4SSukadev Bhattiprolu } 24453af8ee4SSukadev Bhattiprolu 245b87a267eSMiklos Szeredi static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs) 246b87a267eSMiklos Szeredi { 24731af0abbSSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(vfs->mnt_sb); 24831af0abbSSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 24931af0abbSSukadev Bhattiprolu 25031af0abbSSukadev Bhattiprolu if (opts->setuid) 25131af0abbSSukadev Bhattiprolu seq_printf(seq, ",uid=%u", opts->uid); 25231af0abbSSukadev Bhattiprolu if (opts->setgid) 25331af0abbSSukadev Bhattiprolu seq_printf(seq, ",gid=%u", opts->gid); 25431af0abbSSukadev Bhattiprolu seq_printf(seq, ",mode=%03o", opts->mode); 2551f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 2561f8f1e29SSukadev Bhattiprolu seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode); 2571f8f1e29SSukadev Bhattiprolu #endif 258b87a267eSMiklos Szeredi 259b87a267eSMiklos Szeredi return 0; 260b87a267eSMiklos Szeredi } 261b87a267eSMiklos Szeredi 262ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations devpts_sops = { 2631da177e4SLinus Torvalds .statfs = simple_statfs, 2641da177e4SLinus Torvalds .remount_fs = devpts_remount, 265b87a267eSMiklos Szeredi .show_options = devpts_show_options, 2661da177e4SLinus Torvalds }; 2671da177e4SLinus Torvalds 268e76b7c01SSukadev Bhattiprolu static void *new_pts_fs_info(void) 269e76b7c01SSukadev Bhattiprolu { 270e76b7c01SSukadev Bhattiprolu struct pts_fs_info *fsi; 271e76b7c01SSukadev Bhattiprolu 272e76b7c01SSukadev Bhattiprolu fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL); 273e76b7c01SSukadev Bhattiprolu if (!fsi) 274e76b7c01SSukadev Bhattiprolu return NULL; 275e76b7c01SSukadev Bhattiprolu 276e76b7c01SSukadev Bhattiprolu ida_init(&fsi->allocated_ptys); 27731af0abbSSukadev Bhattiprolu fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE; 2781f8f1e29SSukadev Bhattiprolu fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; 279e76b7c01SSukadev Bhattiprolu 280e76b7c01SSukadev Bhattiprolu return fsi; 281e76b7c01SSukadev Bhattiprolu } 282e76b7c01SSukadev Bhattiprolu 2831da177e4SLinus Torvalds static int 2841da177e4SLinus Torvalds devpts_fill_super(struct super_block *s, void *data, int silent) 2851da177e4SLinus Torvalds { 2861da177e4SLinus Torvalds struct inode *inode; 2871da177e4SLinus Torvalds 2881da177e4SLinus Torvalds s->s_blocksize = 1024; 2891da177e4SLinus Torvalds s->s_blocksize_bits = 10; 2901da177e4SLinus Torvalds s->s_magic = DEVPTS_SUPER_MAGIC; 2911da177e4SLinus Torvalds s->s_op = &devpts_sops; 2921da177e4SLinus Torvalds s->s_time_gran = 1; 2931da177e4SLinus Torvalds 294e76b7c01SSukadev Bhattiprolu s->s_fs_info = new_pts_fs_info(); 295e76b7c01SSukadev Bhattiprolu if (!s->s_fs_info) 296e76b7c01SSukadev Bhattiprolu goto fail; 297e76b7c01SSukadev Bhattiprolu 2981da177e4SLinus Torvalds inode = new_inode(s); 2991da177e4SLinus Torvalds if (!inode) 300e76b7c01SSukadev Bhattiprolu goto free_fsi; 3011da177e4SLinus Torvalds inode->i_ino = 1; 3021da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 3031da177e4SLinus Torvalds inode->i_blocks = 0; 3041da177e4SLinus Torvalds inode->i_uid = inode->i_gid = 0; 3051da177e4SLinus Torvalds inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; 3061da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 3071da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 3081da177e4SLinus Torvalds inode->i_nlink = 2; 3091da177e4SLinus Torvalds 31059e55e6cSSukadev Bhattiprolu s->s_root = d_alloc_root(inode); 3111da177e4SLinus Torvalds if (s->s_root) 3121da177e4SLinus Torvalds return 0; 3131da177e4SLinus Torvalds 3141da177e4SLinus Torvalds printk("devpts: get root dentry failed\n"); 3151da177e4SLinus Torvalds iput(inode); 316e76b7c01SSukadev Bhattiprolu 317e76b7c01SSukadev Bhattiprolu free_fsi: 318e76b7c01SSukadev Bhattiprolu kfree(s->s_fs_info); 3191da177e4SLinus Torvalds fail: 3201da177e4SLinus Torvalds return -ENOMEM; 3211da177e4SLinus Torvalds } 3221da177e4SLinus Torvalds 323d4076ac5SSukadev Bhattiprolu static int compare_init_pts_sb(struct super_block *s, void *p) 324d4076ac5SSukadev Bhattiprolu { 325d4076ac5SSukadev Bhattiprolu if (devpts_mnt) 326d4076ac5SSukadev Bhattiprolu return devpts_mnt->mnt_sb == s; 3272a1b2dc0SSukadev Bhattiprolu return 0; 3282a1b2dc0SSukadev Bhattiprolu } 3292a1b2dc0SSukadev Bhattiprolu 3302a1b2dc0SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 3312a1b2dc0SSukadev Bhattiprolu /* 3322a1b2dc0SSukadev Bhattiprolu * Safely parse the mount options in @data and update @opts. 3332a1b2dc0SSukadev Bhattiprolu * 3342a1b2dc0SSukadev Bhattiprolu * devpts ends up parsing options two times during mount, due to the 3352a1b2dc0SSukadev Bhattiprolu * two modes of operation it supports. The first parse occurs in 3362a1b2dc0SSukadev Bhattiprolu * devpts_get_sb() when determining the mode (single-instance or 3372a1b2dc0SSukadev Bhattiprolu * multi-instance mode). The second parse happens in devpts_remount() 3382a1b2dc0SSukadev Bhattiprolu * or new_pts_mount() depending on the mode. 3392a1b2dc0SSukadev Bhattiprolu * 3402a1b2dc0SSukadev Bhattiprolu * Parsing of options modifies the @data making subsequent parsing 3412a1b2dc0SSukadev Bhattiprolu * incorrect. So make a local copy of @data and parse it. 3422a1b2dc0SSukadev Bhattiprolu * 3432a1b2dc0SSukadev Bhattiprolu * Return: 0 On success, -errno on error 3442a1b2dc0SSukadev Bhattiprolu */ 3452a1b2dc0SSukadev Bhattiprolu static int safe_parse_mount_options(void *data, struct pts_mount_opts *opts) 3462a1b2dc0SSukadev Bhattiprolu { 3472a1b2dc0SSukadev Bhattiprolu int rc; 3482a1b2dc0SSukadev Bhattiprolu void *datacp; 3492a1b2dc0SSukadev Bhattiprolu 3502a1b2dc0SSukadev Bhattiprolu if (!data) 3512a1b2dc0SSukadev Bhattiprolu return 0; 3522a1b2dc0SSukadev Bhattiprolu 3532a1b2dc0SSukadev Bhattiprolu /* Use kstrdup() ? */ 3542a1b2dc0SSukadev Bhattiprolu datacp = kmalloc(PAGE_SIZE, GFP_KERNEL); 3552a1b2dc0SSukadev Bhattiprolu if (!datacp) 3562a1b2dc0SSukadev Bhattiprolu return -ENOMEM; 3572a1b2dc0SSukadev Bhattiprolu 3582a1b2dc0SSukadev Bhattiprolu memcpy(datacp, data, PAGE_SIZE); 3592a1b2dc0SSukadev Bhattiprolu rc = parse_mount_options((char *)datacp, PARSE_MOUNT, opts); 3602a1b2dc0SSukadev Bhattiprolu kfree(datacp); 3612a1b2dc0SSukadev Bhattiprolu 3622a1b2dc0SSukadev Bhattiprolu return rc; 3632a1b2dc0SSukadev Bhattiprolu } 3642a1b2dc0SSukadev Bhattiprolu 3652a1b2dc0SSukadev Bhattiprolu /* 3662a1b2dc0SSukadev Bhattiprolu * Mount a new (private) instance of devpts. PTYs created in this 3672a1b2dc0SSukadev Bhattiprolu * instance are independent of the PTYs in other devpts instances. 3682a1b2dc0SSukadev Bhattiprolu */ 3692a1b2dc0SSukadev Bhattiprolu static int new_pts_mount(struct file_system_type *fs_type, int flags, 3702a1b2dc0SSukadev Bhattiprolu void *data, struct vfsmount *mnt) 3712a1b2dc0SSukadev Bhattiprolu { 3722a1b2dc0SSukadev Bhattiprolu int err; 3732a1b2dc0SSukadev Bhattiprolu struct pts_fs_info *fsi; 3742a1b2dc0SSukadev Bhattiprolu struct pts_mount_opts *opts; 3752a1b2dc0SSukadev Bhattiprolu 3762a1b2dc0SSukadev Bhattiprolu printk(KERN_NOTICE "devpts: newinstance mount\n"); 3772a1b2dc0SSukadev Bhattiprolu 3782a1b2dc0SSukadev Bhattiprolu err = get_sb_nodev(fs_type, flags, data, devpts_fill_super, mnt); 3792a1b2dc0SSukadev Bhattiprolu if (err) 3802a1b2dc0SSukadev Bhattiprolu return err; 3812a1b2dc0SSukadev Bhattiprolu 3822a1b2dc0SSukadev Bhattiprolu fsi = DEVPTS_SB(mnt->mnt_sb); 3832a1b2dc0SSukadev Bhattiprolu opts = &fsi->mount_opts; 3842a1b2dc0SSukadev Bhattiprolu 3852a1b2dc0SSukadev Bhattiprolu err = parse_mount_options(data, PARSE_MOUNT, opts); 3862a1b2dc0SSukadev Bhattiprolu if (err) 3872a1b2dc0SSukadev Bhattiprolu goto fail; 3882a1b2dc0SSukadev Bhattiprolu 3892a1b2dc0SSukadev Bhattiprolu err = mknod_ptmx(mnt->mnt_sb); 3902a1b2dc0SSukadev Bhattiprolu if (err) 3912a1b2dc0SSukadev Bhattiprolu goto fail; 392d4076ac5SSukadev Bhattiprolu 393d4076ac5SSukadev Bhattiprolu return 0; 3942a1b2dc0SSukadev Bhattiprolu 3952a1b2dc0SSukadev Bhattiprolu fail: 3962a1b2dc0SSukadev Bhattiprolu dput(mnt->mnt_sb->s_root); 3972a1b2dc0SSukadev Bhattiprolu deactivate_super(mnt->mnt_sb); 3982a1b2dc0SSukadev Bhattiprolu return err; 3992a1b2dc0SSukadev Bhattiprolu } 4002a1b2dc0SSukadev Bhattiprolu 4012a1b2dc0SSukadev Bhattiprolu /* 4022a1b2dc0SSukadev Bhattiprolu * Check if 'newinstance' mount option was specified in @data. 4032a1b2dc0SSukadev Bhattiprolu * 4042a1b2dc0SSukadev Bhattiprolu * Return: -errno on error (eg: invalid mount options specified) 4052a1b2dc0SSukadev Bhattiprolu * : 1 if 'newinstance' mount option was specified 4062a1b2dc0SSukadev Bhattiprolu * : 0 if 'newinstance' mount option was NOT specified 4072a1b2dc0SSukadev Bhattiprolu */ 4082a1b2dc0SSukadev Bhattiprolu static int is_new_instance_mount(void *data) 4092a1b2dc0SSukadev Bhattiprolu { 4102a1b2dc0SSukadev Bhattiprolu int rc; 4112a1b2dc0SSukadev Bhattiprolu struct pts_mount_opts opts; 4122a1b2dc0SSukadev Bhattiprolu 4132a1b2dc0SSukadev Bhattiprolu if (!data) 4142a1b2dc0SSukadev Bhattiprolu return 0; 4152a1b2dc0SSukadev Bhattiprolu 4162a1b2dc0SSukadev Bhattiprolu rc = safe_parse_mount_options(data, &opts); 4172a1b2dc0SSukadev Bhattiprolu if (!rc) 4182a1b2dc0SSukadev Bhattiprolu rc = opts.newinstance; 4192a1b2dc0SSukadev Bhattiprolu 4202a1b2dc0SSukadev Bhattiprolu return rc; 421d4076ac5SSukadev Bhattiprolu } 422d4076ac5SSukadev Bhattiprolu 423d4076ac5SSukadev Bhattiprolu /* 424d4076ac5SSukadev Bhattiprolu * get_init_pts_sb() 425d4076ac5SSukadev Bhattiprolu * 426d4076ac5SSukadev Bhattiprolu * This interface is needed to support multiple namespace semantics in 427d4076ac5SSukadev Bhattiprolu * devpts while preserving backward compatibility of the current 'single- 428d4076ac5SSukadev Bhattiprolu * namespace' semantics. i.e all mounts of devpts without the 'newinstance' 429d4076ac5SSukadev Bhattiprolu * mount option should bind to the initial kernel mount, like 430d4076ac5SSukadev Bhattiprolu * get_sb_single(). 431d4076ac5SSukadev Bhattiprolu * 432d4076ac5SSukadev Bhattiprolu * Mounts with 'newinstance' option create a new private namespace. 433d4076ac5SSukadev Bhattiprolu * 434d4076ac5SSukadev Bhattiprolu * But for single-mount semantics, devpts cannot use get_sb_single(), 435d4076ac5SSukadev Bhattiprolu * because get_sb_single()/sget() find and use the super-block from 436d4076ac5SSukadev Bhattiprolu * the most recent mount of devpts. But that recent mount may be a 437d4076ac5SSukadev Bhattiprolu * 'newinstance' mount and get_sb_single() would pick the newinstance 438d4076ac5SSukadev Bhattiprolu * super-block instead of the initial super-block. 439d4076ac5SSukadev Bhattiprolu * 440d4076ac5SSukadev Bhattiprolu * This interface is identical to get_sb_single() except that it 441d4076ac5SSukadev Bhattiprolu * consistently selects the 'single-namespace' superblock even in the 442d4076ac5SSukadev Bhattiprolu * presence of the private namespace (i.e 'newinstance') super-blocks. 443d4076ac5SSukadev Bhattiprolu */ 444d4076ac5SSukadev Bhattiprolu static int get_init_pts_sb(struct file_system_type *fs_type, int flags, 445d4076ac5SSukadev Bhattiprolu void *data, struct vfsmount *mnt) 446d4076ac5SSukadev Bhattiprolu { 447d4076ac5SSukadev Bhattiprolu struct super_block *s; 448d4076ac5SSukadev Bhattiprolu int error; 449d4076ac5SSukadev Bhattiprolu 450d4076ac5SSukadev Bhattiprolu s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL); 451d4076ac5SSukadev Bhattiprolu if (IS_ERR(s)) 452d4076ac5SSukadev Bhattiprolu return PTR_ERR(s); 453d4076ac5SSukadev Bhattiprolu 454d4076ac5SSukadev Bhattiprolu if (!s->s_root) { 455d4076ac5SSukadev Bhattiprolu s->s_flags = flags; 456d4076ac5SSukadev Bhattiprolu error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0); 457d4076ac5SSukadev Bhattiprolu if (error) { 458d4076ac5SSukadev Bhattiprolu up_write(&s->s_umount); 459d4076ac5SSukadev Bhattiprolu deactivate_super(s); 460d4076ac5SSukadev Bhattiprolu return error; 461d4076ac5SSukadev Bhattiprolu } 462d4076ac5SSukadev Bhattiprolu s->s_flags |= MS_ACTIVE; 463d4076ac5SSukadev Bhattiprolu } 464d4076ac5SSukadev Bhattiprolu do_remount_sb(s, flags, data, 0); 465d4076ac5SSukadev Bhattiprolu return simple_set_mnt(mnt, s); 466d4076ac5SSukadev Bhattiprolu } 467d4076ac5SSukadev Bhattiprolu 4682a1b2dc0SSukadev Bhattiprolu /* 4692a1b2dc0SSukadev Bhattiprolu * Mount or remount the initial kernel mount of devpts. This type of 4702a1b2dc0SSukadev Bhattiprolu * mount maintains the legacy, single-instance semantics, while the 4712a1b2dc0SSukadev Bhattiprolu * kernel still allows multiple-instances. 4722a1b2dc0SSukadev Bhattiprolu */ 4732a1b2dc0SSukadev Bhattiprolu static int init_pts_mount(struct file_system_type *fs_type, int flags, 4742a1b2dc0SSukadev Bhattiprolu void *data, struct vfsmount *mnt) 4752a1b2dc0SSukadev Bhattiprolu { 4762a1b2dc0SSukadev Bhattiprolu int err; 4772a1b2dc0SSukadev Bhattiprolu 4782a1b2dc0SSukadev Bhattiprolu err = get_init_pts_sb(fs_type, flags, data, mnt); 4792a1b2dc0SSukadev Bhattiprolu if (err) 4802a1b2dc0SSukadev Bhattiprolu return err; 4812a1b2dc0SSukadev Bhattiprolu 4822a1b2dc0SSukadev Bhattiprolu err = mknod_ptmx(mnt->mnt_sb); 4832a1b2dc0SSukadev Bhattiprolu if (err) { 4842a1b2dc0SSukadev Bhattiprolu dput(mnt->mnt_sb->s_root); 4852a1b2dc0SSukadev Bhattiprolu deactivate_super(mnt->mnt_sb); 4862a1b2dc0SSukadev Bhattiprolu } 4872a1b2dc0SSukadev Bhattiprolu 4882a1b2dc0SSukadev Bhattiprolu return err; 4892a1b2dc0SSukadev Bhattiprolu } 4902a1b2dc0SSukadev Bhattiprolu 491454e2398SDavid Howells static int devpts_get_sb(struct file_system_type *fs_type, 492454e2398SDavid Howells int flags, const char *dev_name, void *data, struct vfsmount *mnt) 4931da177e4SLinus Torvalds { 4942a1b2dc0SSukadev Bhattiprolu int new; 4952a1b2dc0SSukadev Bhattiprolu 4962a1b2dc0SSukadev Bhattiprolu new = is_new_instance_mount(data); 4972a1b2dc0SSukadev Bhattiprolu if (new < 0) 4982a1b2dc0SSukadev Bhattiprolu return new; 4992a1b2dc0SSukadev Bhattiprolu 5002a1b2dc0SSukadev Bhattiprolu if (new) 5012a1b2dc0SSukadev Bhattiprolu return new_pts_mount(fs_type, flags, data, mnt); 5022a1b2dc0SSukadev Bhattiprolu 5032a1b2dc0SSukadev Bhattiprolu return init_pts_mount(fs_type, flags, data, mnt); 5041da177e4SLinus Torvalds } 5052a1b2dc0SSukadev Bhattiprolu #else 5062a1b2dc0SSukadev Bhattiprolu /* 5072a1b2dc0SSukadev Bhattiprolu * This supports only the legacy single-instance semantics (no 5082a1b2dc0SSukadev Bhattiprolu * multiple-instance semantics) 5092a1b2dc0SSukadev Bhattiprolu */ 5102a1b2dc0SSukadev Bhattiprolu static int devpts_get_sb(struct file_system_type *fs_type, int flags, 5112a1b2dc0SSukadev Bhattiprolu const char *dev_name, void *data, struct vfsmount *mnt) 5122a1b2dc0SSukadev Bhattiprolu { 5132a1b2dc0SSukadev Bhattiprolu return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt); 5142a1b2dc0SSukadev Bhattiprolu } 5152a1b2dc0SSukadev Bhattiprolu #endif 5161da177e4SLinus Torvalds 517e76b7c01SSukadev Bhattiprolu static void devpts_kill_sb(struct super_block *sb) 518e76b7c01SSukadev Bhattiprolu { 519e76b7c01SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 520e76b7c01SSukadev Bhattiprolu 521e76b7c01SSukadev Bhattiprolu kfree(fsi); 5221f8f1e29SSukadev Bhattiprolu kill_litter_super(sb); 523e76b7c01SSukadev Bhattiprolu } 524e76b7c01SSukadev Bhattiprolu 5251da177e4SLinus Torvalds static struct file_system_type devpts_fs_type = { 5261da177e4SLinus Torvalds .owner = THIS_MODULE, 5271da177e4SLinus Torvalds .name = "devpts", 5281da177e4SLinus Torvalds .get_sb = devpts_get_sb, 529e76b7c01SSukadev Bhattiprolu .kill_sb = devpts_kill_sb, 5301da177e4SLinus Torvalds }; 5311da177e4SLinus Torvalds 5321da177e4SLinus Torvalds /* 5331da177e4SLinus Torvalds * The normal naming convention is simply /dev/pts/<number>; this conforms 5341da177e4SLinus Torvalds * to the System V naming convention 5351da177e4SLinus Torvalds */ 5361da177e4SLinus Torvalds 53715f1a633SSukadev Bhattiprolu int devpts_new_index(struct inode *ptmx_inode) 538718a9163SSukadev Bhattiprolu { 539e76b7c01SSukadev Bhattiprolu struct super_block *sb = pts_sb_from_inode(ptmx_inode); 540e76b7c01SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 541718a9163SSukadev Bhattiprolu int index; 5427ee7c12bSAlexey Dobriyan int ida_ret; 543718a9163SSukadev Bhattiprolu 544718a9163SSukadev Bhattiprolu retry: 545e76b7c01SSukadev Bhattiprolu if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) { 546718a9163SSukadev Bhattiprolu return -ENOMEM; 547718a9163SSukadev Bhattiprolu } 548718a9163SSukadev Bhattiprolu 549718a9163SSukadev Bhattiprolu mutex_lock(&allocated_ptys_lock); 550e76b7c01SSukadev Bhattiprolu ida_ret = ida_get_new(&fsi->allocated_ptys, &index); 5517ee7c12bSAlexey Dobriyan if (ida_ret < 0) { 552718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 5537ee7c12bSAlexey Dobriyan if (ida_ret == -EAGAIN) 554718a9163SSukadev Bhattiprolu goto retry; 555718a9163SSukadev Bhattiprolu return -EIO; 556718a9163SSukadev Bhattiprolu } 557718a9163SSukadev Bhattiprolu 558718a9163SSukadev Bhattiprolu if (index >= pty_limit) { 559e76b7c01SSukadev Bhattiprolu ida_remove(&fsi->allocated_ptys, index); 560718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 561718a9163SSukadev Bhattiprolu return -EIO; 562718a9163SSukadev Bhattiprolu } 563718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 564718a9163SSukadev Bhattiprolu return index; 565718a9163SSukadev Bhattiprolu } 566718a9163SSukadev Bhattiprolu 56715f1a633SSukadev Bhattiprolu void devpts_kill_index(struct inode *ptmx_inode, int idx) 568718a9163SSukadev Bhattiprolu { 569e76b7c01SSukadev Bhattiprolu struct super_block *sb = pts_sb_from_inode(ptmx_inode); 570e76b7c01SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 571e76b7c01SSukadev Bhattiprolu 572718a9163SSukadev Bhattiprolu mutex_lock(&allocated_ptys_lock); 573e76b7c01SSukadev Bhattiprolu ida_remove(&fsi->allocated_ptys, idx); 574718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 575718a9163SSukadev Bhattiprolu } 576718a9163SSukadev Bhattiprolu 57715f1a633SSukadev Bhattiprolu int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty) 5781da177e4SLinus Torvalds { 579718a9163SSukadev Bhattiprolu int number = tty->index; /* tty layer puts index from devpts_new_index() in here */ 5801da177e4SLinus Torvalds struct tty_driver *driver = tty->driver; 5811da177e4SLinus Torvalds dev_t device = MKDEV(driver->major, driver->minor_start+number); 5821da177e4SLinus Torvalds struct dentry *dentry; 58359e55e6cSSukadev Bhattiprolu struct super_block *sb = pts_sb_from_inode(ptmx_inode); 58459e55e6cSSukadev Bhattiprolu struct inode *inode = new_inode(sb); 58559e55e6cSSukadev Bhattiprolu struct dentry *root = sb->s_root; 58631af0abbSSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 58731af0abbSSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 58889a52e10SSukadev Bhattiprolu char s[12]; 5891da177e4SLinus Torvalds 5901da177e4SLinus Torvalds /* We're supposed to be given the slave end of a pty */ 5911da177e4SLinus Torvalds BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY); 5921da177e4SLinus Torvalds BUG_ON(driver->subtype != PTY_TYPE_SLAVE); 5931da177e4SLinus Torvalds 5941da177e4SLinus Torvalds if (!inode) 5951da177e4SLinus Torvalds return -ENOMEM; 5961da177e4SLinus Torvalds 5971da177e4SLinus Torvalds inode->i_ino = number+2; 598ec4c2aacSDavid Howells inode->i_uid = config.setuid ? config.uid : current_fsuid(); 599ec4c2aacSDavid Howells inode->i_gid = config.setgid ? config.gid : current_fsgid(); 6001da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 60131af0abbSSukadev Bhattiprolu init_special_inode(inode, S_IFCHR|opts->mode, device); 6028e18e294STheodore Ts'o inode->i_private = tty; 603a6f37daaSSukadev Bhattiprolu tty->driver_data = inode; 6041da177e4SLinus Torvalds 60589a52e10SSukadev Bhattiprolu sprintf(s, "%d", number); 60689a52e10SSukadev Bhattiprolu 60759e55e6cSSukadev Bhattiprolu mutex_lock(&root->d_inode->i_mutex); 60889a52e10SSukadev Bhattiprolu 60959e55e6cSSukadev Bhattiprolu dentry = d_alloc_name(root, s); 61089a52e10SSukadev Bhattiprolu if (!IS_ERR(dentry)) { 61189a52e10SSukadev Bhattiprolu d_add(dentry, inode); 61259e55e6cSSukadev Bhattiprolu fsnotify_create(root->d_inode, dentry); 6133972b7f6SFlorin Malita } 6141da177e4SLinus Torvalds 61559e55e6cSSukadev Bhattiprolu mutex_unlock(&root->d_inode->i_mutex); 6161da177e4SLinus Torvalds 6171da177e4SLinus Torvalds return 0; 6181da177e4SLinus Torvalds } 6191da177e4SLinus Torvalds 62015f1a633SSukadev Bhattiprolu struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number) 6211da177e4SLinus Torvalds { 622527b3e47SSukadev Bhattiprolu BUG_ON(pts_inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); 6231da177e4SLinus Torvalds 624527b3e47SSukadev Bhattiprolu if (pts_inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) 625527b3e47SSukadev Bhattiprolu return (struct tty_struct *)pts_inode->i_private; 626527b3e47SSukadev Bhattiprolu return NULL; 6271da177e4SLinus Torvalds } 6281da177e4SLinus Torvalds 62915f1a633SSukadev Bhattiprolu void devpts_pty_kill(struct tty_struct *tty) 6301da177e4SLinus Torvalds { 631a6f37daaSSukadev Bhattiprolu struct inode *inode = tty->driver_data; 63259e55e6cSSukadev Bhattiprolu struct super_block *sb = pts_sb_from_inode(inode); 63359e55e6cSSukadev Bhattiprolu struct dentry *root = sb->s_root; 634a6f37daaSSukadev Bhattiprolu struct dentry *dentry; 6351da177e4SLinus Torvalds 636a6f37daaSSukadev Bhattiprolu BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); 637a6f37daaSSukadev Bhattiprolu 63859e55e6cSSukadev Bhattiprolu mutex_lock(&root->d_inode->i_mutex); 639a6f37daaSSukadev Bhattiprolu 640a6f37daaSSukadev Bhattiprolu dentry = d_find_alias(inode); 6412a1b2dc0SSukadev Bhattiprolu if (IS_ERR(dentry)) 6422a1b2dc0SSukadev Bhattiprolu goto out; 6432a1b2dc0SSukadev Bhattiprolu 6442a1b2dc0SSukadev Bhattiprolu if (dentry) { 6451da177e4SLinus Torvalds inode->i_nlink--; 6461da177e4SLinus Torvalds d_delete(dentry); 6472a1b2dc0SSukadev Bhattiprolu dput(dentry); // d_alloc_name() in devpts_pty_new() 6481da177e4SLinus Torvalds } 649a6f37daaSSukadev Bhattiprolu 6502a1b2dc0SSukadev Bhattiprolu dput(dentry); // d_find_alias above 6512a1b2dc0SSukadev Bhattiprolu 6522a1b2dc0SSukadev Bhattiprolu out: 65359e55e6cSSukadev Bhattiprolu mutex_unlock(&root->d_inode->i_mutex); 6541da177e4SLinus Torvalds } 6551da177e4SLinus Torvalds 6561da177e4SLinus Torvalds static int __init init_devpts_fs(void) 6571da177e4SLinus Torvalds { 6581da177e4SLinus Torvalds int err = register_filesystem(&devpts_fs_type); 6591da177e4SLinus Torvalds if (!err) { 6601da177e4SLinus Torvalds devpts_mnt = kern_mount(&devpts_fs_type); 6611da177e4SLinus Torvalds if (IS_ERR(devpts_mnt)) 6621da177e4SLinus Torvalds err = PTR_ERR(devpts_mnt); 6631da177e4SLinus Torvalds } 6641da177e4SLinus Torvalds return err; 6651da177e4SLinus Torvalds } 6661da177e4SLinus Torvalds 6671da177e4SLinus Torvalds static void __exit exit_devpts_fs(void) 6681da177e4SLinus Torvalds { 6691da177e4SLinus Torvalds unregister_filesystem(&devpts_fs_type); 6701da177e4SLinus Torvalds mntput(devpts_mnt); 6711da177e4SLinus Torvalds } 6721da177e4SLinus Torvalds 6731da177e4SLinus Torvalds module_init(init_devpts_fs) 6741da177e4SLinus Torvalds module_exit(exit_devpts_fs) 6751da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 676