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 1304541a2fSFabian Frederick #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 1404541a2fSFabian Frederick 151da177e4SLinus Torvalds #include <linux/module.h> 161da177e4SLinus Torvalds #include <linux/init.h> 171da177e4SLinus Torvalds #include <linux/fs.h> 181da177e4SLinus Torvalds #include <linux/sched.h> 191da177e4SLinus Torvalds #include <linux/namei.h> 205a0e3ad6STejun Heo #include <linux/slab.h> 211da177e4SLinus Torvalds #include <linux/mount.h> 221da177e4SLinus Torvalds #include <linux/tty.h> 23718a9163SSukadev Bhattiprolu #include <linux/mutex.h> 241fd7317dSNick Black #include <linux/magic.h> 25718a9163SSukadev Bhattiprolu #include <linux/idr.h> 261da177e4SLinus Torvalds #include <linux/devpts_fs.h> 277a673c6bSDomen Puncer #include <linux/parser.h> 283972b7f6SFlorin Malita #include <linux/fsnotify.h> 29b87a267eSMiklos Szeredi #include <linux/seq_file.h> 301da177e4SLinus Torvalds 31b87a267eSMiklos Szeredi #define DEVPTS_DEFAULT_MODE 0600 321f8f1e29SSukadev Bhattiprolu /* 331f8f1e29SSukadev Bhattiprolu * ptmx is a new node in /dev/pts and will be unused in legacy (single- 341f8f1e29SSukadev Bhattiprolu * instance) mode. To prevent surprises in user space, set permissions of 351f8f1e29SSukadev Bhattiprolu * ptmx to 0. Use 'chmod' or remount with '-o ptmxmode' to set meaningful 361f8f1e29SSukadev Bhattiprolu * permissions. 371f8f1e29SSukadev Bhattiprolu */ 381f8f1e29SSukadev Bhattiprolu #define DEVPTS_DEFAULT_PTMX_MODE 0000 39527b3e47SSukadev Bhattiprolu #define PTMX_MINOR 2 40b87a267eSMiklos Szeredi 41a4834c10SKonstantin Khlebnikov /* 42a4834c10SKonstantin Khlebnikov * sysctl support for setting limits on the number of Unix98 ptys allocated. 43a4834c10SKonstantin Khlebnikov * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly. 44a4834c10SKonstantin Khlebnikov */ 45a4834c10SKonstantin Khlebnikov static int pty_limit = NR_UNIX98_PTY_DEFAULT; 46e9aba515SKonstantin Khlebnikov static int pty_reserve = NR_UNIX98_PTY_RESERVE; 47a4834c10SKonstantin Khlebnikov static int pty_limit_min; 48e9aba515SKonstantin Khlebnikov static int pty_limit_max = INT_MAX; 49a4834c10SKonstantin Khlebnikov static int pty_count; 50a4834c10SKonstantin Khlebnikov 51a4834c10SKonstantin Khlebnikov static struct ctl_table pty_table[] = { 52a4834c10SKonstantin Khlebnikov { 53a4834c10SKonstantin Khlebnikov .procname = "max", 54a4834c10SKonstantin Khlebnikov .maxlen = sizeof(int), 55a4834c10SKonstantin Khlebnikov .mode = 0644, 56a4834c10SKonstantin Khlebnikov .data = &pty_limit, 57a4834c10SKonstantin Khlebnikov .proc_handler = proc_dointvec_minmax, 58a4834c10SKonstantin Khlebnikov .extra1 = &pty_limit_min, 59a4834c10SKonstantin Khlebnikov .extra2 = &pty_limit_max, 60a4834c10SKonstantin Khlebnikov }, { 61e9aba515SKonstantin Khlebnikov .procname = "reserve", 62e9aba515SKonstantin Khlebnikov .maxlen = sizeof(int), 63e9aba515SKonstantin Khlebnikov .mode = 0644, 64e9aba515SKonstantin Khlebnikov .data = &pty_reserve, 65e9aba515SKonstantin Khlebnikov .proc_handler = proc_dointvec_minmax, 66e9aba515SKonstantin Khlebnikov .extra1 = &pty_limit_min, 67e9aba515SKonstantin Khlebnikov .extra2 = &pty_limit_max, 68e9aba515SKonstantin Khlebnikov }, { 69a4834c10SKonstantin Khlebnikov .procname = "nr", 70a4834c10SKonstantin Khlebnikov .maxlen = sizeof(int), 71a4834c10SKonstantin Khlebnikov .mode = 0444, 72a4834c10SKonstantin Khlebnikov .data = &pty_count, 73a4834c10SKonstantin Khlebnikov .proc_handler = proc_dointvec, 74a4834c10SKonstantin Khlebnikov }, 75a4834c10SKonstantin Khlebnikov {} 76a4834c10SKonstantin Khlebnikov }; 77a4834c10SKonstantin Khlebnikov 78a4834c10SKonstantin Khlebnikov static struct ctl_table pty_kern_table[] = { 79a4834c10SKonstantin Khlebnikov { 80a4834c10SKonstantin Khlebnikov .procname = "pty", 81a4834c10SKonstantin Khlebnikov .mode = 0555, 82a4834c10SKonstantin Khlebnikov .child = pty_table, 83a4834c10SKonstantin Khlebnikov }, 84a4834c10SKonstantin Khlebnikov {} 85a4834c10SKonstantin Khlebnikov }; 86a4834c10SKonstantin Khlebnikov 87a4834c10SKonstantin Khlebnikov static struct ctl_table pty_root_table[] = { 88a4834c10SKonstantin Khlebnikov { 89a4834c10SKonstantin Khlebnikov .procname = "kernel", 90a4834c10SKonstantin Khlebnikov .mode = 0555, 91a4834c10SKonstantin Khlebnikov .child = pty_kern_table, 92a4834c10SKonstantin Khlebnikov }, 93a4834c10SKonstantin Khlebnikov {} 94a4834c10SKonstantin Khlebnikov }; 95a4834c10SKonstantin Khlebnikov 96718a9163SSukadev Bhattiprolu static DEFINE_MUTEX(allocated_ptys_lock); 97718a9163SSukadev Bhattiprolu 981da177e4SLinus Torvalds static struct vfsmount *devpts_mnt; 991da177e4SLinus Torvalds 10031af0abbSSukadev Bhattiprolu struct pts_mount_opts { 1011da177e4SLinus Torvalds int setuid; 1021da177e4SLinus Torvalds int setgid; 103f04c6ce2SEric W. Biederman kuid_t uid; 104f04c6ce2SEric W. Biederman kgid_t gid; 1051da177e4SLinus Torvalds umode_t mode; 1061f8f1e29SSukadev Bhattiprolu umode_t ptmxmode; 1072a1b2dc0SSukadev Bhattiprolu int newinstance; 108e9aba515SKonstantin Khlebnikov int max; 10931af0abbSSukadev Bhattiprolu }; 1101da177e4SLinus Torvalds 1117a673c6bSDomen Puncer enum { 112e9aba515SKonstantin Khlebnikov Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance, Opt_max, 1137a673c6bSDomen Puncer Opt_err 1147a673c6bSDomen Puncer }; 1157a673c6bSDomen Puncer 116a447c093SSteven Whitehouse static const match_table_t tokens = { 1177a673c6bSDomen Puncer {Opt_uid, "uid=%u"}, 1187a673c6bSDomen Puncer {Opt_gid, "gid=%u"}, 1197a673c6bSDomen Puncer {Opt_mode, "mode=%o"}, 1201f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 1211f8f1e29SSukadev Bhattiprolu {Opt_ptmxmode, "ptmxmode=%o"}, 1222a1b2dc0SSukadev Bhattiprolu {Opt_newinstance, "newinstance"}, 123e9aba515SKonstantin Khlebnikov {Opt_max, "max=%d"}, 1241f8f1e29SSukadev Bhattiprolu #endif 1257a673c6bSDomen Puncer {Opt_err, NULL} 1267a673c6bSDomen Puncer }; 1277a673c6bSDomen Puncer 128e76b7c01SSukadev Bhattiprolu struct pts_fs_info { 129e76b7c01SSukadev Bhattiprolu struct ida allocated_ptys; 13031af0abbSSukadev Bhattiprolu struct pts_mount_opts mount_opts; 13167245ff3SLinus Torvalds struct super_block *sb; 1321f8f1e29SSukadev Bhattiprolu struct dentry *ptmx_dentry; 133e76b7c01SSukadev Bhattiprolu }; 134e76b7c01SSukadev Bhattiprolu 135e76b7c01SSukadev Bhattiprolu static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb) 136e76b7c01SSukadev Bhattiprolu { 137e76b7c01SSukadev Bhattiprolu return sb->s_fs_info; 138e76b7c01SSukadev Bhattiprolu } 139e76b7c01SSukadev Bhattiprolu 14059e55e6cSSukadev Bhattiprolu static inline struct super_block *pts_sb_from_inode(struct inode *inode) 14159e55e6cSSukadev Bhattiprolu { 1422a1b2dc0SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 14359e55e6cSSukadev Bhattiprolu if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) 14459e55e6cSSukadev Bhattiprolu return inode->i_sb; 1452a1b2dc0SSukadev Bhattiprolu #endif 1469ce71148SJosh Triplett if (!devpts_mnt) 1479ce71148SJosh Triplett return NULL; 14859e55e6cSSukadev Bhattiprolu return devpts_mnt->mnt_sb; 14959e55e6cSSukadev Bhattiprolu } 15059e55e6cSSukadev Bhattiprolu 1512a1b2dc0SSukadev Bhattiprolu #define PARSE_MOUNT 0 1522a1b2dc0SSukadev Bhattiprolu #define PARSE_REMOUNT 1 1532a1b2dc0SSukadev Bhattiprolu 1541f71ebedSSukadev Bhattiprolu /* 1551f71ebedSSukadev Bhattiprolu * parse_mount_options(): 1561f71ebedSSukadev Bhattiprolu * Set @opts to mount options specified in @data. If an option is not 1571f71ebedSSukadev Bhattiprolu * specified in @data, set it to its default value. The exception is 1581f71ebedSSukadev Bhattiprolu * 'newinstance' option which can only be set/cleared on a mount (i.e. 1591f71ebedSSukadev Bhattiprolu * cannot be changed during remount). 1601f71ebedSSukadev Bhattiprolu * 1611f71ebedSSukadev Bhattiprolu * Note: @data may be NULL (in which case all options are set to default). 1621f71ebedSSukadev Bhattiprolu */ 1632a1b2dc0SSukadev Bhattiprolu static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) 1641da177e4SLinus Torvalds { 1657a673c6bSDomen Puncer char *p; 166f04c6ce2SEric W. Biederman kuid_t uid; 167f04c6ce2SEric W. Biederman kgid_t gid; 1681da177e4SLinus Torvalds 16931af0abbSSukadev Bhattiprolu opts->setuid = 0; 17031af0abbSSukadev Bhattiprolu opts->setgid = 0; 171f04c6ce2SEric W. Biederman opts->uid = GLOBAL_ROOT_UID; 172f04c6ce2SEric W. Biederman opts->gid = GLOBAL_ROOT_GID; 17331af0abbSSukadev Bhattiprolu opts->mode = DEVPTS_DEFAULT_MODE; 1741f8f1e29SSukadev Bhattiprolu opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; 175e9aba515SKonstantin Khlebnikov opts->max = NR_UNIX98_PTY_MAX; 1767a673c6bSDomen Puncer 1772a1b2dc0SSukadev Bhattiprolu /* newinstance makes sense only on initial mount */ 1782a1b2dc0SSukadev Bhattiprolu if (op == PARSE_MOUNT) 1792a1b2dc0SSukadev Bhattiprolu opts->newinstance = 0; 1802a1b2dc0SSukadev Bhattiprolu 1817a673c6bSDomen Puncer while ((p = strsep(&data, ",")) != NULL) { 1827a673c6bSDomen Puncer substring_t args[MAX_OPT_ARGS]; 1837a673c6bSDomen Puncer int token; 1847a673c6bSDomen Puncer int option; 1857a673c6bSDomen Puncer 1867a673c6bSDomen Puncer if (!*p) 1871da177e4SLinus Torvalds continue; 1887a673c6bSDomen Puncer 1897a673c6bSDomen Puncer token = match_token(p, tokens, args); 1907a673c6bSDomen Puncer switch (token) { 1917a673c6bSDomen Puncer case Opt_uid: 1927a673c6bSDomen Puncer if (match_int(&args[0], &option)) 1937a673c6bSDomen Puncer return -EINVAL; 194f04c6ce2SEric W. Biederman uid = make_kuid(current_user_ns(), option); 195f04c6ce2SEric W. Biederman if (!uid_valid(uid)) 196f04c6ce2SEric W. Biederman return -EINVAL; 197f04c6ce2SEric W. Biederman opts->uid = uid; 19831af0abbSSukadev Bhattiprolu opts->setuid = 1; 1997a673c6bSDomen Puncer break; 2007a673c6bSDomen Puncer case Opt_gid: 2017a673c6bSDomen Puncer if (match_int(&args[0], &option)) 2027a673c6bSDomen Puncer return -EINVAL; 203f04c6ce2SEric W. Biederman gid = make_kgid(current_user_ns(), option); 204f04c6ce2SEric W. Biederman if (!gid_valid(gid)) 205f04c6ce2SEric W. Biederman return -EINVAL; 206f04c6ce2SEric W. Biederman opts->gid = gid; 20731af0abbSSukadev Bhattiprolu opts->setgid = 1; 2087a673c6bSDomen Puncer break; 2097a673c6bSDomen Puncer case Opt_mode: 2107a673c6bSDomen Puncer if (match_octal(&args[0], &option)) 2117a673c6bSDomen Puncer return -EINVAL; 21231af0abbSSukadev Bhattiprolu opts->mode = option & S_IALLUGO; 2137a673c6bSDomen Puncer break; 2141f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 2151f8f1e29SSukadev Bhattiprolu case Opt_ptmxmode: 2161f8f1e29SSukadev Bhattiprolu if (match_octal(&args[0], &option)) 2171f8f1e29SSukadev Bhattiprolu return -EINVAL; 2181f8f1e29SSukadev Bhattiprolu opts->ptmxmode = option & S_IALLUGO; 2191f8f1e29SSukadev Bhattiprolu break; 2202a1b2dc0SSukadev Bhattiprolu case Opt_newinstance: 2212a1b2dc0SSukadev Bhattiprolu /* newinstance makes sense only on initial mount */ 2222a1b2dc0SSukadev Bhattiprolu if (op == PARSE_MOUNT) 2232a1b2dc0SSukadev Bhattiprolu opts->newinstance = 1; 2242a1b2dc0SSukadev Bhattiprolu break; 225e9aba515SKonstantin Khlebnikov case Opt_max: 226e9aba515SKonstantin Khlebnikov if (match_int(&args[0], &option) || 227e9aba515SKonstantin Khlebnikov option < 0 || option > NR_UNIX98_PTY_MAX) 228e9aba515SKonstantin Khlebnikov return -EINVAL; 229e9aba515SKonstantin Khlebnikov opts->max = option; 230e9aba515SKonstantin Khlebnikov break; 2311f8f1e29SSukadev Bhattiprolu #endif 2327a673c6bSDomen Puncer default: 23304541a2fSFabian Frederick pr_err("called with bogus options\n"); 2341da177e4SLinus Torvalds return -EINVAL; 2351da177e4SLinus Torvalds } 2361da177e4SLinus Torvalds } 2371da177e4SLinus Torvalds 2381da177e4SLinus Torvalds return 0; 2391da177e4SLinus Torvalds } 2401da177e4SLinus Torvalds 2411f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 2421f8f1e29SSukadev Bhattiprolu static int mknod_ptmx(struct super_block *sb) 24353af8ee4SSukadev Bhattiprolu { 2441f8f1e29SSukadev Bhattiprolu int mode; 2451f8f1e29SSukadev Bhattiprolu int rc = -ENOMEM; 2461f8f1e29SSukadev Bhattiprolu struct dentry *dentry; 2471f8f1e29SSukadev Bhattiprolu struct inode *inode; 2481f8f1e29SSukadev Bhattiprolu struct dentry *root = sb->s_root; 24953af8ee4SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 25053af8ee4SSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 251ec2aa8e8SEric W. Biederman kuid_t root_uid; 252ec2aa8e8SEric W. Biederman kgid_t root_gid; 253ec2aa8e8SEric W. Biederman 254ec2aa8e8SEric W. Biederman root_uid = make_kuid(current_user_ns(), 0); 255ec2aa8e8SEric W. Biederman root_gid = make_kgid(current_user_ns(), 0); 256ec2aa8e8SEric W. Biederman if (!uid_valid(root_uid) || !gid_valid(root_gid)) 257ec2aa8e8SEric W. Biederman return -EINVAL; 25853af8ee4SSukadev Bhattiprolu 2595955102cSAl Viro inode_lock(d_inode(root)); 2601f8f1e29SSukadev Bhattiprolu 2611f8f1e29SSukadev Bhattiprolu /* If we have already created ptmx node, return */ 2621f8f1e29SSukadev Bhattiprolu if (fsi->ptmx_dentry) { 2631f8f1e29SSukadev Bhattiprolu rc = 0; 2641f8f1e29SSukadev Bhattiprolu goto out; 2651f8f1e29SSukadev Bhattiprolu } 2661f8f1e29SSukadev Bhattiprolu 2671f8f1e29SSukadev Bhattiprolu dentry = d_alloc_name(root, "ptmx"); 2681f8f1e29SSukadev Bhattiprolu if (!dentry) { 26904541a2fSFabian Frederick pr_err("Unable to alloc dentry for ptmx node\n"); 2701f8f1e29SSukadev Bhattiprolu goto out; 2711f8f1e29SSukadev Bhattiprolu } 2721f8f1e29SSukadev Bhattiprolu 2731f8f1e29SSukadev Bhattiprolu /* 2741f8f1e29SSukadev Bhattiprolu * Create a new 'ptmx' node in this mount of devpts. 2751f8f1e29SSukadev Bhattiprolu */ 2761f8f1e29SSukadev Bhattiprolu inode = new_inode(sb); 2771f8f1e29SSukadev Bhattiprolu if (!inode) { 27804541a2fSFabian Frederick pr_err("Unable to alloc inode for ptmx node\n"); 2791f8f1e29SSukadev Bhattiprolu dput(dentry); 2801f8f1e29SSukadev Bhattiprolu goto out; 2811f8f1e29SSukadev Bhattiprolu } 2821f8f1e29SSukadev Bhattiprolu 2831f8f1e29SSukadev Bhattiprolu inode->i_ino = 2; 2841f8f1e29SSukadev Bhattiprolu inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 2851f8f1e29SSukadev Bhattiprolu 2861f8f1e29SSukadev Bhattiprolu mode = S_IFCHR|opts->ptmxmode; 2871f8f1e29SSukadev Bhattiprolu init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2)); 288ec2aa8e8SEric W. Biederman inode->i_uid = root_uid; 289ec2aa8e8SEric W. Biederman inode->i_gid = root_gid; 2901f8f1e29SSukadev Bhattiprolu 2911f8f1e29SSukadev Bhattiprolu d_add(dentry, inode); 2921f8f1e29SSukadev Bhattiprolu 2931f8f1e29SSukadev Bhattiprolu fsi->ptmx_dentry = dentry; 2941f8f1e29SSukadev Bhattiprolu rc = 0; 2951f8f1e29SSukadev Bhattiprolu out: 2965955102cSAl Viro inode_unlock(d_inode(root)); 2971f8f1e29SSukadev Bhattiprolu return rc; 2981f8f1e29SSukadev Bhattiprolu } 2991f8f1e29SSukadev Bhattiprolu 3001f8f1e29SSukadev Bhattiprolu static void update_ptmx_mode(struct pts_fs_info *fsi) 3011f8f1e29SSukadev Bhattiprolu { 3021f8f1e29SSukadev Bhattiprolu struct inode *inode; 3031f8f1e29SSukadev Bhattiprolu if (fsi->ptmx_dentry) { 3042b0143b5SDavid Howells inode = d_inode(fsi->ptmx_dentry); 3051f8f1e29SSukadev Bhattiprolu inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode; 3061f8f1e29SSukadev Bhattiprolu } 3071f8f1e29SSukadev Bhattiprolu } 3081f8f1e29SSukadev Bhattiprolu #else 3091f8f1e29SSukadev Bhattiprolu static inline void update_ptmx_mode(struct pts_fs_info *fsi) 3101f8f1e29SSukadev Bhattiprolu { 3111f8f1e29SSukadev Bhattiprolu return; 3121f8f1e29SSukadev Bhattiprolu } 3131f8f1e29SSukadev Bhattiprolu #endif 3141f8f1e29SSukadev Bhattiprolu 3151f8f1e29SSukadev Bhattiprolu static int devpts_remount(struct super_block *sb, int *flags, char *data) 3161f8f1e29SSukadev Bhattiprolu { 3171f8f1e29SSukadev Bhattiprolu int err; 3181f8f1e29SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 3191f8f1e29SSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 3201f8f1e29SSukadev Bhattiprolu 32102b9984dSTheodore Ts'o sync_filesystem(sb); 3222a1b2dc0SSukadev Bhattiprolu err = parse_mount_options(data, PARSE_REMOUNT, opts); 3231f8f1e29SSukadev Bhattiprolu 3241f8f1e29SSukadev Bhattiprolu /* 3251f8f1e29SSukadev Bhattiprolu * parse_mount_options() restores options to default values 3261f8f1e29SSukadev Bhattiprolu * before parsing and may have changed ptmxmode. So, update the 3271f8f1e29SSukadev Bhattiprolu * mode in the inode too. Bogus options don't fail the remount, 3281f8f1e29SSukadev Bhattiprolu * so do this even on error return. 3291f8f1e29SSukadev Bhattiprolu */ 3301f8f1e29SSukadev Bhattiprolu update_ptmx_mode(fsi); 3311f8f1e29SSukadev Bhattiprolu 3321f8f1e29SSukadev Bhattiprolu return err; 33353af8ee4SSukadev Bhattiprolu } 33453af8ee4SSukadev Bhattiprolu 33534c80b1dSAl Viro static int devpts_show_options(struct seq_file *seq, struct dentry *root) 336b87a267eSMiklos Szeredi { 33734c80b1dSAl Viro struct pts_fs_info *fsi = DEVPTS_SB(root->d_sb); 33831af0abbSSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 33931af0abbSSukadev Bhattiprolu 34031af0abbSSukadev Bhattiprolu if (opts->setuid) 34104541a2fSFabian Frederick seq_printf(seq, ",uid=%u", 34204541a2fSFabian Frederick from_kuid_munged(&init_user_ns, opts->uid)); 34331af0abbSSukadev Bhattiprolu if (opts->setgid) 34404541a2fSFabian Frederick seq_printf(seq, ",gid=%u", 34504541a2fSFabian Frederick from_kgid_munged(&init_user_ns, opts->gid)); 34631af0abbSSukadev Bhattiprolu seq_printf(seq, ",mode=%03o", opts->mode); 3471f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 3481f8f1e29SSukadev Bhattiprolu seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode); 349e9aba515SKonstantin Khlebnikov if (opts->max < NR_UNIX98_PTY_MAX) 350e9aba515SKonstantin Khlebnikov seq_printf(seq, ",max=%d", opts->max); 3511f8f1e29SSukadev Bhattiprolu #endif 352b87a267eSMiklos Szeredi 353b87a267eSMiklos Szeredi return 0; 354b87a267eSMiklos Szeredi } 355b87a267eSMiklos Szeredi 356ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations devpts_sops = { 3571da177e4SLinus Torvalds .statfs = simple_statfs, 3581da177e4SLinus Torvalds .remount_fs = devpts_remount, 359b87a267eSMiklos Szeredi .show_options = devpts_show_options, 3601da177e4SLinus Torvalds }; 3611da177e4SLinus Torvalds 36267245ff3SLinus Torvalds static void *new_pts_fs_info(struct super_block *sb) 363e76b7c01SSukadev Bhattiprolu { 364e76b7c01SSukadev Bhattiprolu struct pts_fs_info *fsi; 365e76b7c01SSukadev Bhattiprolu 366e76b7c01SSukadev Bhattiprolu fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL); 367e76b7c01SSukadev Bhattiprolu if (!fsi) 368e76b7c01SSukadev Bhattiprolu return NULL; 369e76b7c01SSukadev Bhattiprolu 370e76b7c01SSukadev Bhattiprolu ida_init(&fsi->allocated_ptys); 37131af0abbSSukadev Bhattiprolu fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE; 3721f8f1e29SSukadev Bhattiprolu fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; 37367245ff3SLinus Torvalds fsi->sb = sb; 374e76b7c01SSukadev Bhattiprolu 375e76b7c01SSukadev Bhattiprolu return fsi; 376e76b7c01SSukadev Bhattiprolu } 377e76b7c01SSukadev Bhattiprolu 3781da177e4SLinus Torvalds static int 3791da177e4SLinus Torvalds devpts_fill_super(struct super_block *s, void *data, int silent) 3801da177e4SLinus Torvalds { 3811da177e4SLinus Torvalds struct inode *inode; 3821da177e4SLinus Torvalds 3831da177e4SLinus Torvalds s->s_blocksize = 1024; 3841da177e4SLinus Torvalds s->s_blocksize_bits = 10; 3851da177e4SLinus Torvalds s->s_magic = DEVPTS_SUPER_MAGIC; 3861da177e4SLinus Torvalds s->s_op = &devpts_sops; 3871da177e4SLinus Torvalds s->s_time_gran = 1; 3881da177e4SLinus Torvalds 38967245ff3SLinus Torvalds s->s_fs_info = new_pts_fs_info(s); 390e76b7c01SSukadev Bhattiprolu if (!s->s_fs_info) 391e76b7c01SSukadev Bhattiprolu goto fail; 392e76b7c01SSukadev Bhattiprolu 3931da177e4SLinus Torvalds inode = new_inode(s); 3941da177e4SLinus Torvalds if (!inode) 3953850aba7SAl Viro goto fail; 3961da177e4SLinus Torvalds inode->i_ino = 1; 3971da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 3981da177e4SLinus Torvalds inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; 3991da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 4001da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 401bfe86848SMiklos Szeredi set_nlink(inode, 2); 4021da177e4SLinus Torvalds 40348fde701SAl Viro s->s_root = d_make_root(inode); 4041da177e4SLinus Torvalds if (s->s_root) 4051da177e4SLinus Torvalds return 0; 4061da177e4SLinus Torvalds 40704541a2fSFabian Frederick pr_err("get root dentry failed\n"); 408e76b7c01SSukadev Bhattiprolu 4091da177e4SLinus Torvalds fail: 4101da177e4SLinus Torvalds return -ENOMEM; 4111da177e4SLinus Torvalds } 4121da177e4SLinus Torvalds 4138c056e5bSAndrew Morton #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 414d4076ac5SSukadev Bhattiprolu static int compare_init_pts_sb(struct super_block *s, void *p) 415d4076ac5SSukadev Bhattiprolu { 416d4076ac5SSukadev Bhattiprolu if (devpts_mnt) 417d4076ac5SSukadev Bhattiprolu return devpts_mnt->mnt_sb == s; 4182a1b2dc0SSukadev Bhattiprolu return 0; 4192a1b2dc0SSukadev Bhattiprolu } 4202a1b2dc0SSukadev Bhattiprolu 4212a1b2dc0SSukadev Bhattiprolu /* 422fc14f2feSAl Viro * devpts_mount() 423289f00e2SSukadev Bhattiprolu * 4241bd79035SSukadev Bhattiprolu * If the '-o newinstance' mount option was specified, mount a new 4251bd79035SSukadev Bhattiprolu * (private) instance of devpts. PTYs created in this instance are 4261bd79035SSukadev Bhattiprolu * independent of the PTYs in other devpts instances. 427d4076ac5SSukadev Bhattiprolu * 4281bd79035SSukadev Bhattiprolu * If the '-o newinstance' option was not specified, mount/remount the 4291bd79035SSukadev Bhattiprolu * initial kernel mount of devpts. This type of mount gives the 4301bd79035SSukadev Bhattiprolu * legacy, single-instance semantics. 431d4076ac5SSukadev Bhattiprolu * 4321bd79035SSukadev Bhattiprolu * The 'newinstance' option is needed to support multiple namespace 4331bd79035SSukadev Bhattiprolu * semantics in devpts while preserving backward compatibility of the 4341bd79035SSukadev Bhattiprolu * current 'single-namespace' semantics. i.e all mounts of devpts 4351bd79035SSukadev Bhattiprolu * without the 'newinstance' mount option should bind to the initial 436fc14f2feSAl Viro * kernel mount, like mount_single(). 437d4076ac5SSukadev Bhattiprolu * 4381bd79035SSukadev Bhattiprolu * Mounts with 'newinstance' option create a new, private namespace. 4391bd79035SSukadev Bhattiprolu * 4401bd79035SSukadev Bhattiprolu * NOTE: 4411bd79035SSukadev Bhattiprolu * 442fc14f2feSAl Viro * For single-mount semantics, devpts cannot use mount_single(), 443fc14f2feSAl Viro * because mount_single()/sget() find and use the super-block from 444d4076ac5SSukadev Bhattiprolu * the most recent mount of devpts. But that recent mount may be a 445fc14f2feSAl Viro * 'newinstance' mount and mount_single() would pick the newinstance 446d4076ac5SSukadev Bhattiprolu * super-block instead of the initial super-block. 447d4076ac5SSukadev Bhattiprolu */ 448fc14f2feSAl Viro static struct dentry *devpts_mount(struct file_system_type *fs_type, 449fc14f2feSAl Viro int flags, const char *dev_name, void *data) 4501da177e4SLinus Torvalds { 451482984f0SSukadev Bhattiprolu int error; 452482984f0SSukadev Bhattiprolu struct pts_mount_opts opts; 4531bd79035SSukadev Bhattiprolu struct super_block *s; 4542a1b2dc0SSukadev Bhattiprolu 455482984f0SSukadev Bhattiprolu error = parse_mount_options(data, PARSE_MOUNT, &opts); 456482984f0SSukadev Bhattiprolu if (error) 457fc14f2feSAl Viro return ERR_PTR(error); 458482984f0SSukadev Bhattiprolu 459ec2aa8e8SEric W. Biederman /* Require newinstance for all user namespace mounts to ensure 460ec2aa8e8SEric W. Biederman * the mount options are not changed. 461ec2aa8e8SEric W. Biederman */ 462ec2aa8e8SEric W. Biederman if ((current_user_ns() != &init_user_ns) && !opts.newinstance) 463ec2aa8e8SEric W. Biederman return ERR_PTR(-EINVAL); 464ec2aa8e8SEric W. Biederman 465482984f0SSukadev Bhattiprolu if (opts.newinstance) 4669249e17fSDavid Howells s = sget(fs_type, NULL, set_anon_super, flags, NULL); 467482984f0SSukadev Bhattiprolu else 4689249e17fSDavid Howells s = sget(fs_type, compare_init_pts_sb, set_anon_super, flags, 4699249e17fSDavid Howells NULL); 470945cf2c7SSukadev Bhattiprolu 4711bd79035SSukadev Bhattiprolu if (IS_ERR(s)) 472fc14f2feSAl Viro return ERR_CAST(s); 4731bd79035SSukadev Bhattiprolu 4741bd79035SSukadev Bhattiprolu if (!s->s_root) { 4751bd79035SSukadev Bhattiprolu error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0); 476945cf2c7SSukadev Bhattiprolu if (error) 4771bd79035SSukadev Bhattiprolu goto out_undo_sget; 4781bd79035SSukadev Bhattiprolu s->s_flags |= MS_ACTIVE; 4791bd79035SSukadev Bhattiprolu } 480945cf2c7SSukadev Bhattiprolu 4811bd79035SSukadev Bhattiprolu memcpy(&(DEVPTS_SB(s))->mount_opts, &opts, sizeof(opts)); 4821bd79035SSukadev Bhattiprolu 4831bd79035SSukadev Bhattiprolu error = mknod_ptmx(s); 484945cf2c7SSukadev Bhattiprolu if (error) 48589468071SAl Viro goto out_undo_sget; 48689468071SAl Viro 487fc14f2feSAl Viro return dget(s->s_root); 488945cf2c7SSukadev Bhattiprolu 4891bd79035SSukadev Bhattiprolu out_undo_sget: 4906f5bbff9SAl Viro deactivate_locked_super(s); 491fc14f2feSAl Viro return ERR_PTR(error); 492482984f0SSukadev Bhattiprolu } 493482984f0SSukadev Bhattiprolu 4942a1b2dc0SSukadev Bhattiprolu #else 4952a1b2dc0SSukadev Bhattiprolu /* 4962a1b2dc0SSukadev Bhattiprolu * This supports only the legacy single-instance semantics (no 4972a1b2dc0SSukadev Bhattiprolu * multiple-instance semantics) 4982a1b2dc0SSukadev Bhattiprolu */ 499fc14f2feSAl Viro static struct dentry *devpts_mount(struct file_system_type *fs_type, int flags, 500fc14f2feSAl Viro const char *dev_name, void *data) 5012a1b2dc0SSukadev Bhattiprolu { 502fc14f2feSAl Viro return mount_single(fs_type, flags, data, devpts_fill_super); 5032a1b2dc0SSukadev Bhattiprolu } 5042a1b2dc0SSukadev Bhattiprolu #endif 5051da177e4SLinus Torvalds 506e76b7c01SSukadev Bhattiprolu static void devpts_kill_sb(struct super_block *sb) 507e76b7c01SSukadev Bhattiprolu { 508e76b7c01SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 509e76b7c01SSukadev Bhattiprolu 51066da0e1fSIlija Hadzic ida_destroy(&fsi->allocated_ptys); 511e76b7c01SSukadev Bhattiprolu kfree(fsi); 5121f8f1e29SSukadev Bhattiprolu kill_litter_super(sb); 513e76b7c01SSukadev Bhattiprolu } 514e76b7c01SSukadev Bhattiprolu 5151da177e4SLinus Torvalds static struct file_system_type devpts_fs_type = { 5161da177e4SLinus Torvalds .name = "devpts", 517fc14f2feSAl Viro .mount = devpts_mount, 518e76b7c01SSukadev Bhattiprolu .kill_sb = devpts_kill_sb, 519ec2aa8e8SEric W. Biederman #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 520ec2aa8e8SEric W. Biederman .fs_flags = FS_USERNS_MOUNT | FS_USERNS_DEV_MOUNT, 521ec2aa8e8SEric W. Biederman #endif 5221da177e4SLinus Torvalds }; 5231da177e4SLinus Torvalds 5241da177e4SLinus Torvalds /* 5251da177e4SLinus Torvalds * The normal naming convention is simply /dev/pts/<number>; this conforms 5261da177e4SLinus Torvalds * to the System V naming convention 5271da177e4SLinus Torvalds */ 5281da177e4SLinus Torvalds 52967245ff3SLinus Torvalds int devpts_new_index(struct pts_fs_info *fsi) 530718a9163SSukadev Bhattiprolu { 531718a9163SSukadev Bhattiprolu int index; 5327ee7c12bSAlexey Dobriyan int ida_ret; 533718a9163SSukadev Bhattiprolu 53467245ff3SLinus Torvalds if (!fsi) 5359ce71148SJosh Triplett return -ENODEV; 5369ce71148SJosh Triplett 537718a9163SSukadev Bhattiprolu retry: 538835aa440SAlan Cox if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) 539718a9163SSukadev Bhattiprolu return -ENOMEM; 540718a9163SSukadev Bhattiprolu 541718a9163SSukadev Bhattiprolu mutex_lock(&allocated_ptys_lock); 542e9aba515SKonstantin Khlebnikov if (pty_count >= pty_limit - 543e9aba515SKonstantin Khlebnikov (fsi->mount_opts.newinstance ? pty_reserve : 0)) { 544e9aba515SKonstantin Khlebnikov mutex_unlock(&allocated_ptys_lock); 545e9aba515SKonstantin Khlebnikov return -ENOSPC; 546e9aba515SKonstantin Khlebnikov } 547e9aba515SKonstantin Khlebnikov 548e76b7c01SSukadev Bhattiprolu ida_ret = ida_get_new(&fsi->allocated_ptys, &index); 5497ee7c12bSAlexey Dobriyan if (ida_ret < 0) { 550718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 5517ee7c12bSAlexey Dobriyan if (ida_ret == -EAGAIN) 552718a9163SSukadev Bhattiprolu goto retry; 553718a9163SSukadev Bhattiprolu return -EIO; 554718a9163SSukadev Bhattiprolu } 555718a9163SSukadev Bhattiprolu 556e9aba515SKonstantin Khlebnikov if (index >= fsi->mount_opts.max) { 557e76b7c01SSukadev Bhattiprolu ida_remove(&fsi->allocated_ptys, index); 558718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 559e9aba515SKonstantin Khlebnikov return -ENOSPC; 560718a9163SSukadev Bhattiprolu } 561a4834c10SKonstantin Khlebnikov pty_count++; 562718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 563718a9163SSukadev Bhattiprolu return index; 564718a9163SSukadev Bhattiprolu } 565718a9163SSukadev Bhattiprolu 56667245ff3SLinus Torvalds void devpts_kill_index(struct pts_fs_info *fsi, int idx) 567718a9163SSukadev Bhattiprolu { 568718a9163SSukadev Bhattiprolu mutex_lock(&allocated_ptys_lock); 569e76b7c01SSukadev Bhattiprolu ida_remove(&fsi->allocated_ptys, idx); 570a4834c10SKonstantin Khlebnikov pty_count--; 571718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 572718a9163SSukadev Bhattiprolu } 573718a9163SSukadev Bhattiprolu 5741f55c718SHerton R. Krzesinski /* 5751f55c718SHerton R. Krzesinski * pty code needs to hold extra references in case of last /dev/tty close 5761f55c718SHerton R. Krzesinski */ 57767245ff3SLinus Torvalds struct pts_fs_info *devpts_get_ref(struct inode *ptmx_inode, struct file *file) 5781f55c718SHerton R. Krzesinski { 57967245ff3SLinus Torvalds struct super_block *sb; 58067245ff3SLinus Torvalds struct pts_fs_info *fsi; 58167245ff3SLinus Torvalds 58267245ff3SLinus Torvalds sb = pts_sb_from_inode(ptmx_inode); 58367245ff3SLinus Torvalds if (!sb) 58467245ff3SLinus Torvalds return NULL; 58567245ff3SLinus Torvalds fsi = DEVPTS_SB(sb); 58667245ff3SLinus Torvalds if (!fsi) 58767245ff3SLinus Torvalds return NULL; 5881f55c718SHerton R. Krzesinski 5891f55c718SHerton R. Krzesinski atomic_inc(&sb->s_active); 59067245ff3SLinus Torvalds return fsi; 5911f55c718SHerton R. Krzesinski } 5921f55c718SHerton R. Krzesinski 59367245ff3SLinus Torvalds void devpts_put_ref(struct pts_fs_info *fsi) 5941f55c718SHerton R. Krzesinski { 59567245ff3SLinus Torvalds deactivate_super(fsi->sb); 5961f55c718SHerton R. Krzesinski } 5971f55c718SHerton R. Krzesinski 5981dcb8e6dSJiri Slaby /** 5991dcb8e6dSJiri Slaby * devpts_pty_new -- create a new inode in /dev/pts/ 6001dcb8e6dSJiri Slaby * @ptmx_inode: inode of the master 6011dcb8e6dSJiri Slaby * @device: major+minor of the node to be created 6021dcb8e6dSJiri Slaby * @index: used as a name of the node 6031dcb8e6dSJiri Slaby * @priv: what's given back by devpts_get_priv 6041dcb8e6dSJiri Slaby * 6051dcb8e6dSJiri Slaby * The created inode is returned. Remove it from /dev/pts/ by devpts_pty_kill. 6061dcb8e6dSJiri Slaby */ 6078ead9dd5SLinus Torvalds struct dentry *devpts_pty_new(struct pts_fs_info *fsi, int index, void *priv) 6081da177e4SLinus Torvalds { 6091da177e4SLinus Torvalds struct dentry *dentry; 61067245ff3SLinus Torvalds struct super_block *sb; 611162b97cfSJiri Slaby struct inode *inode; 6129ce71148SJosh Triplett struct dentry *root; 6139ce71148SJosh Triplett struct pts_mount_opts *opts; 61489a52e10SSukadev Bhattiprolu char s[12]; 6151da177e4SLinus Torvalds 61667245ff3SLinus Torvalds if (!fsi) 6179ce71148SJosh Triplett return ERR_PTR(-ENODEV); 6189ce71148SJosh Triplett 61967245ff3SLinus Torvalds sb = fsi->sb; 6209ce71148SJosh Triplett root = sb->s_root; 6219ce71148SJosh Triplett opts = &fsi->mount_opts; 6229ce71148SJosh Triplett 623162b97cfSJiri Slaby inode = new_inode(sb); 6241da177e4SLinus Torvalds if (!inode) 625162b97cfSJiri Slaby return ERR_PTR(-ENOMEM); 6261da177e4SLinus Torvalds 627f11afb61SJiri Slaby inode->i_ino = index + 3; 628d0eafc7dSDavid Howells inode->i_uid = opts->setuid ? opts->uid : current_fsuid(); 629d0eafc7dSDavid Howells inode->i_gid = opts->setgid ? opts->gid : current_fsgid(); 6301da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 6318ead9dd5SLinus Torvalds init_special_inode(inode, S_IFCHR|opts->mode, MKDEV(UNIX98_PTY_SLAVE_MAJOR, index)); 6321da177e4SLinus Torvalds 633f11afb61SJiri Slaby sprintf(s, "%d", index); 63489a52e10SSukadev Bhattiprolu 63559e55e6cSSukadev Bhattiprolu dentry = d_alloc_name(root, s); 636b12d1259SAndrey Vagin if (dentry) { 6378ead9dd5SLinus Torvalds dentry->d_fsdata = priv; 63889a52e10SSukadev Bhattiprolu d_add(dentry, inode); 6392b0143b5SDavid Howells fsnotify_create(d_inode(root), dentry); 640aa597bc1SAndrey Vagin } else { 641aa597bc1SAndrey Vagin iput(inode); 6428ead9dd5SLinus Torvalds dentry = ERR_PTR(-ENOMEM); 6433972b7f6SFlorin Malita } 6441da177e4SLinus Torvalds 6458ead9dd5SLinus Torvalds return dentry; 6461da177e4SLinus Torvalds } 6471da177e4SLinus Torvalds 6481dcb8e6dSJiri Slaby /** 6491dcb8e6dSJiri Slaby * devpts_get_priv -- get private data for a slave 6501dcb8e6dSJiri Slaby * @pts_inode: inode of the slave 6511dcb8e6dSJiri Slaby * 6521dcb8e6dSJiri Slaby * Returns whatever was passed as priv in devpts_pty_new for a given inode. 6531dcb8e6dSJiri Slaby */ 6548ead9dd5SLinus Torvalds void *devpts_get_priv(struct dentry *dentry) 6551da177e4SLinus Torvalds { 6568ead9dd5SLinus Torvalds WARN_ON_ONCE(dentry->d_sb->s_magic != DEVPTS_SUPER_MAGIC); 6578ead9dd5SLinus Torvalds return dentry->d_fsdata; 6581da177e4SLinus Torvalds } 6591da177e4SLinus Torvalds 6601dcb8e6dSJiri Slaby /** 6611dcb8e6dSJiri Slaby * devpts_pty_kill -- remove inode form /dev/pts/ 6621dcb8e6dSJiri Slaby * @inode: inode of the slave to be removed 6631dcb8e6dSJiri Slaby * 6641dcb8e6dSJiri Slaby * This is an inverse operation of devpts_pty_new. 6651dcb8e6dSJiri Slaby */ 6668ead9dd5SLinus Torvalds void devpts_pty_kill(struct dentry *dentry) 6671da177e4SLinus Torvalds { 6688ead9dd5SLinus Torvalds WARN_ON_ONCE(dentry->d_sb->s_magic != DEVPTS_SUPER_MAGIC); 6691da177e4SLinus Torvalds 6708ead9dd5SLinus Torvalds dentry->d_fsdata = NULL; 6718ead9dd5SLinus Torvalds drop_nlink(dentry->d_inode); 6721da177e4SLinus Torvalds d_delete(dentry); 673835aa440SAlan Cox dput(dentry); /* d_alloc_name() in devpts_pty_new() */ 6741da177e4SLinus Torvalds } 6751da177e4SLinus Torvalds 6761da177e4SLinus Torvalds static int __init init_devpts_fs(void) 6771da177e4SLinus Torvalds { 6781da177e4SLinus Torvalds int err = register_filesystem(&devpts_fs_type); 679a4834c10SKonstantin Khlebnikov struct ctl_table_header *table; 680a4834c10SKonstantin Khlebnikov 6811da177e4SLinus Torvalds if (!err) { 6829ce71148SJosh Triplett struct vfsmount *mnt; 6839ce71148SJosh Triplett 684a4834c10SKonstantin Khlebnikov table = register_sysctl_table(pty_root_table); 6859ce71148SJosh Triplett mnt = kern_mount(&devpts_fs_type); 6869ce71148SJosh Triplett if (IS_ERR(mnt)) { 6879ce71148SJosh Triplett err = PTR_ERR(mnt); 68893d5581eSAlan Cox unregister_filesystem(&devpts_fs_type); 689a4834c10SKonstantin Khlebnikov unregister_sysctl_table(table); 6909ce71148SJosh Triplett } else { 6919ce71148SJosh Triplett devpts_mnt = mnt; 69293d5581eSAlan Cox } 6931da177e4SLinus Torvalds } 6941da177e4SLinus Torvalds return err; 6951da177e4SLinus Torvalds } 6961da177e4SLinus Torvalds module_init(init_devpts_fs) 697