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; 1311f8f1e29SSukadev Bhattiprolu struct dentry *ptmx_dentry; 132e76b7c01SSukadev Bhattiprolu }; 133e76b7c01SSukadev Bhattiprolu 134e76b7c01SSukadev Bhattiprolu static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb) 135e76b7c01SSukadev Bhattiprolu { 136e76b7c01SSukadev Bhattiprolu return sb->s_fs_info; 137e76b7c01SSukadev Bhattiprolu } 138e76b7c01SSukadev Bhattiprolu 13959e55e6cSSukadev Bhattiprolu static inline struct super_block *pts_sb_from_inode(struct inode *inode) 14059e55e6cSSukadev Bhattiprolu { 1412a1b2dc0SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 14259e55e6cSSukadev Bhattiprolu if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) 14359e55e6cSSukadev Bhattiprolu return inode->i_sb; 1442a1b2dc0SSukadev Bhattiprolu #endif 1459ce71148SJosh Triplett if (!devpts_mnt) 1469ce71148SJosh Triplett return NULL; 14759e55e6cSSukadev Bhattiprolu return devpts_mnt->mnt_sb; 14859e55e6cSSukadev Bhattiprolu } 14959e55e6cSSukadev Bhattiprolu 1502a1b2dc0SSukadev Bhattiprolu #define PARSE_MOUNT 0 1512a1b2dc0SSukadev Bhattiprolu #define PARSE_REMOUNT 1 1522a1b2dc0SSukadev Bhattiprolu 1531f71ebedSSukadev Bhattiprolu /* 1541f71ebedSSukadev Bhattiprolu * parse_mount_options(): 1551f71ebedSSukadev Bhattiprolu * Set @opts to mount options specified in @data. If an option is not 1561f71ebedSSukadev Bhattiprolu * specified in @data, set it to its default value. The exception is 1571f71ebedSSukadev Bhattiprolu * 'newinstance' option which can only be set/cleared on a mount (i.e. 1581f71ebedSSukadev Bhattiprolu * cannot be changed during remount). 1591f71ebedSSukadev Bhattiprolu * 1601f71ebedSSukadev Bhattiprolu * Note: @data may be NULL (in which case all options are set to default). 1611f71ebedSSukadev Bhattiprolu */ 1622a1b2dc0SSukadev Bhattiprolu static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) 1631da177e4SLinus Torvalds { 1647a673c6bSDomen Puncer char *p; 165f04c6ce2SEric W. Biederman kuid_t uid; 166f04c6ce2SEric W. Biederman kgid_t gid; 1671da177e4SLinus Torvalds 16831af0abbSSukadev Bhattiprolu opts->setuid = 0; 16931af0abbSSukadev Bhattiprolu opts->setgid = 0; 170f04c6ce2SEric W. Biederman opts->uid = GLOBAL_ROOT_UID; 171f04c6ce2SEric W. Biederman opts->gid = GLOBAL_ROOT_GID; 17231af0abbSSukadev Bhattiprolu opts->mode = DEVPTS_DEFAULT_MODE; 1731f8f1e29SSukadev Bhattiprolu opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; 174e9aba515SKonstantin Khlebnikov opts->max = NR_UNIX98_PTY_MAX; 1757a673c6bSDomen Puncer 1762a1b2dc0SSukadev Bhattiprolu /* newinstance makes sense only on initial mount */ 1772a1b2dc0SSukadev Bhattiprolu if (op == PARSE_MOUNT) 1782a1b2dc0SSukadev Bhattiprolu opts->newinstance = 0; 1792a1b2dc0SSukadev Bhattiprolu 1807a673c6bSDomen Puncer while ((p = strsep(&data, ",")) != NULL) { 1817a673c6bSDomen Puncer substring_t args[MAX_OPT_ARGS]; 1827a673c6bSDomen Puncer int token; 1837a673c6bSDomen Puncer int option; 1847a673c6bSDomen Puncer 1857a673c6bSDomen Puncer if (!*p) 1861da177e4SLinus Torvalds continue; 1877a673c6bSDomen Puncer 1887a673c6bSDomen Puncer token = match_token(p, tokens, args); 1897a673c6bSDomen Puncer switch (token) { 1907a673c6bSDomen Puncer case Opt_uid: 1917a673c6bSDomen Puncer if (match_int(&args[0], &option)) 1927a673c6bSDomen Puncer return -EINVAL; 193f04c6ce2SEric W. Biederman uid = make_kuid(current_user_ns(), option); 194f04c6ce2SEric W. Biederman if (!uid_valid(uid)) 195f04c6ce2SEric W. Biederman return -EINVAL; 196f04c6ce2SEric W. Biederman opts->uid = uid; 19731af0abbSSukadev Bhattiprolu opts->setuid = 1; 1987a673c6bSDomen Puncer break; 1997a673c6bSDomen Puncer case Opt_gid: 2007a673c6bSDomen Puncer if (match_int(&args[0], &option)) 2017a673c6bSDomen Puncer return -EINVAL; 202f04c6ce2SEric W. Biederman gid = make_kgid(current_user_ns(), option); 203f04c6ce2SEric W. Biederman if (!gid_valid(gid)) 204f04c6ce2SEric W. Biederman return -EINVAL; 205f04c6ce2SEric W. Biederman opts->gid = gid; 20631af0abbSSukadev Bhattiprolu opts->setgid = 1; 2077a673c6bSDomen Puncer break; 2087a673c6bSDomen Puncer case Opt_mode: 2097a673c6bSDomen Puncer if (match_octal(&args[0], &option)) 2107a673c6bSDomen Puncer return -EINVAL; 21131af0abbSSukadev Bhattiprolu opts->mode = option & S_IALLUGO; 2127a673c6bSDomen Puncer break; 2131f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 2141f8f1e29SSukadev Bhattiprolu case Opt_ptmxmode: 2151f8f1e29SSukadev Bhattiprolu if (match_octal(&args[0], &option)) 2161f8f1e29SSukadev Bhattiprolu return -EINVAL; 2171f8f1e29SSukadev Bhattiprolu opts->ptmxmode = option & S_IALLUGO; 2181f8f1e29SSukadev Bhattiprolu break; 2192a1b2dc0SSukadev Bhattiprolu case Opt_newinstance: 2202a1b2dc0SSukadev Bhattiprolu /* newinstance makes sense only on initial mount */ 2212a1b2dc0SSukadev Bhattiprolu if (op == PARSE_MOUNT) 2222a1b2dc0SSukadev Bhattiprolu opts->newinstance = 1; 2232a1b2dc0SSukadev Bhattiprolu break; 224e9aba515SKonstantin Khlebnikov case Opt_max: 225e9aba515SKonstantin Khlebnikov if (match_int(&args[0], &option) || 226e9aba515SKonstantin Khlebnikov option < 0 || option > NR_UNIX98_PTY_MAX) 227e9aba515SKonstantin Khlebnikov return -EINVAL; 228e9aba515SKonstantin Khlebnikov opts->max = option; 229e9aba515SKonstantin Khlebnikov break; 2301f8f1e29SSukadev Bhattiprolu #endif 2317a673c6bSDomen Puncer default: 23204541a2fSFabian Frederick pr_err("called with bogus options\n"); 2331da177e4SLinus Torvalds return -EINVAL; 2341da177e4SLinus Torvalds } 2351da177e4SLinus Torvalds } 2361da177e4SLinus Torvalds 2371da177e4SLinus Torvalds return 0; 2381da177e4SLinus Torvalds } 2391da177e4SLinus Torvalds 2401f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 2411f8f1e29SSukadev Bhattiprolu static int mknod_ptmx(struct super_block *sb) 24253af8ee4SSukadev Bhattiprolu { 2431f8f1e29SSukadev Bhattiprolu int mode; 2441f8f1e29SSukadev Bhattiprolu int rc = -ENOMEM; 2451f8f1e29SSukadev Bhattiprolu struct dentry *dentry; 2461f8f1e29SSukadev Bhattiprolu struct inode *inode; 2471f8f1e29SSukadev Bhattiprolu struct dentry *root = sb->s_root; 24853af8ee4SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 24953af8ee4SSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 250ec2aa8e8SEric W. Biederman kuid_t root_uid; 251ec2aa8e8SEric W. Biederman kgid_t root_gid; 252ec2aa8e8SEric W. Biederman 253ec2aa8e8SEric W. Biederman root_uid = make_kuid(current_user_ns(), 0); 254ec2aa8e8SEric W. Biederman root_gid = make_kgid(current_user_ns(), 0); 255ec2aa8e8SEric W. Biederman if (!uid_valid(root_uid) || !gid_valid(root_gid)) 256ec2aa8e8SEric W. Biederman return -EINVAL; 25753af8ee4SSukadev Bhattiprolu 2585955102cSAl Viro inode_lock(d_inode(root)); 2591f8f1e29SSukadev Bhattiprolu 2601f8f1e29SSukadev Bhattiprolu /* If we have already created ptmx node, return */ 2611f8f1e29SSukadev Bhattiprolu if (fsi->ptmx_dentry) { 2621f8f1e29SSukadev Bhattiprolu rc = 0; 2631f8f1e29SSukadev Bhattiprolu goto out; 2641f8f1e29SSukadev Bhattiprolu } 2651f8f1e29SSukadev Bhattiprolu 2661f8f1e29SSukadev Bhattiprolu dentry = d_alloc_name(root, "ptmx"); 2671f8f1e29SSukadev Bhattiprolu if (!dentry) { 26804541a2fSFabian Frederick pr_err("Unable to alloc dentry for ptmx node\n"); 2691f8f1e29SSukadev Bhattiprolu goto out; 2701f8f1e29SSukadev Bhattiprolu } 2711f8f1e29SSukadev Bhattiprolu 2721f8f1e29SSukadev Bhattiprolu /* 2731f8f1e29SSukadev Bhattiprolu * Create a new 'ptmx' node in this mount of devpts. 2741f8f1e29SSukadev Bhattiprolu */ 2751f8f1e29SSukadev Bhattiprolu inode = new_inode(sb); 2761f8f1e29SSukadev Bhattiprolu if (!inode) { 27704541a2fSFabian Frederick pr_err("Unable to alloc inode for ptmx node\n"); 2781f8f1e29SSukadev Bhattiprolu dput(dentry); 2791f8f1e29SSukadev Bhattiprolu goto out; 2801f8f1e29SSukadev Bhattiprolu } 2811f8f1e29SSukadev Bhattiprolu 2821f8f1e29SSukadev Bhattiprolu inode->i_ino = 2; 2831f8f1e29SSukadev Bhattiprolu inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 2841f8f1e29SSukadev Bhattiprolu 2851f8f1e29SSukadev Bhattiprolu mode = S_IFCHR|opts->ptmxmode; 2861f8f1e29SSukadev Bhattiprolu init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2)); 287ec2aa8e8SEric W. Biederman inode->i_uid = root_uid; 288ec2aa8e8SEric W. Biederman inode->i_gid = root_gid; 2891f8f1e29SSukadev Bhattiprolu 2901f8f1e29SSukadev Bhattiprolu d_add(dentry, inode); 2911f8f1e29SSukadev Bhattiprolu 2921f8f1e29SSukadev Bhattiprolu fsi->ptmx_dentry = dentry; 2931f8f1e29SSukadev Bhattiprolu rc = 0; 2941f8f1e29SSukadev Bhattiprolu out: 2955955102cSAl Viro inode_unlock(d_inode(root)); 2961f8f1e29SSukadev Bhattiprolu return rc; 2971f8f1e29SSukadev Bhattiprolu } 2981f8f1e29SSukadev Bhattiprolu 2991f8f1e29SSukadev Bhattiprolu static void update_ptmx_mode(struct pts_fs_info *fsi) 3001f8f1e29SSukadev Bhattiprolu { 3011f8f1e29SSukadev Bhattiprolu struct inode *inode; 3021f8f1e29SSukadev Bhattiprolu if (fsi->ptmx_dentry) { 3032b0143b5SDavid Howells inode = d_inode(fsi->ptmx_dentry); 3041f8f1e29SSukadev Bhattiprolu inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode; 3051f8f1e29SSukadev Bhattiprolu } 3061f8f1e29SSukadev Bhattiprolu } 3071f8f1e29SSukadev Bhattiprolu #else 3081f8f1e29SSukadev Bhattiprolu static inline void update_ptmx_mode(struct pts_fs_info *fsi) 3091f8f1e29SSukadev Bhattiprolu { 3101f8f1e29SSukadev Bhattiprolu return; 3111f8f1e29SSukadev Bhattiprolu } 3121f8f1e29SSukadev Bhattiprolu #endif 3131f8f1e29SSukadev Bhattiprolu 3141f8f1e29SSukadev Bhattiprolu static int devpts_remount(struct super_block *sb, int *flags, char *data) 3151f8f1e29SSukadev Bhattiprolu { 3161f8f1e29SSukadev Bhattiprolu int err; 3171f8f1e29SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 3181f8f1e29SSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 3191f8f1e29SSukadev Bhattiprolu 32002b9984dSTheodore Ts'o sync_filesystem(sb); 3212a1b2dc0SSukadev Bhattiprolu err = parse_mount_options(data, PARSE_REMOUNT, opts); 3221f8f1e29SSukadev Bhattiprolu 3231f8f1e29SSukadev Bhattiprolu /* 3241f8f1e29SSukadev Bhattiprolu * parse_mount_options() restores options to default values 3251f8f1e29SSukadev Bhattiprolu * before parsing and may have changed ptmxmode. So, update the 3261f8f1e29SSukadev Bhattiprolu * mode in the inode too. Bogus options don't fail the remount, 3271f8f1e29SSukadev Bhattiprolu * so do this even on error return. 3281f8f1e29SSukadev Bhattiprolu */ 3291f8f1e29SSukadev Bhattiprolu update_ptmx_mode(fsi); 3301f8f1e29SSukadev Bhattiprolu 3311f8f1e29SSukadev Bhattiprolu return err; 33253af8ee4SSukadev Bhattiprolu } 33353af8ee4SSukadev Bhattiprolu 33434c80b1dSAl Viro static int devpts_show_options(struct seq_file *seq, struct dentry *root) 335b87a267eSMiklos Szeredi { 33634c80b1dSAl Viro struct pts_fs_info *fsi = DEVPTS_SB(root->d_sb); 33731af0abbSSukadev Bhattiprolu struct pts_mount_opts *opts = &fsi->mount_opts; 33831af0abbSSukadev Bhattiprolu 33931af0abbSSukadev Bhattiprolu if (opts->setuid) 34004541a2fSFabian Frederick seq_printf(seq, ",uid=%u", 34104541a2fSFabian Frederick from_kuid_munged(&init_user_ns, opts->uid)); 34231af0abbSSukadev Bhattiprolu if (opts->setgid) 34304541a2fSFabian Frederick seq_printf(seq, ",gid=%u", 34404541a2fSFabian Frederick from_kgid_munged(&init_user_ns, opts->gid)); 34531af0abbSSukadev Bhattiprolu seq_printf(seq, ",mode=%03o", opts->mode); 3461f8f1e29SSukadev Bhattiprolu #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 3471f8f1e29SSukadev Bhattiprolu seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode); 348e9aba515SKonstantin Khlebnikov if (opts->max < NR_UNIX98_PTY_MAX) 349e9aba515SKonstantin Khlebnikov seq_printf(seq, ",max=%d", opts->max); 3501f8f1e29SSukadev Bhattiprolu #endif 351b87a267eSMiklos Szeredi 352b87a267eSMiklos Szeredi return 0; 353b87a267eSMiklos Szeredi } 354b87a267eSMiklos Szeredi 355ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations devpts_sops = { 3561da177e4SLinus Torvalds .statfs = simple_statfs, 3571da177e4SLinus Torvalds .remount_fs = devpts_remount, 358b87a267eSMiklos Szeredi .show_options = devpts_show_options, 3591da177e4SLinus Torvalds }; 3601da177e4SLinus Torvalds 361e76b7c01SSukadev Bhattiprolu static void *new_pts_fs_info(void) 362e76b7c01SSukadev Bhattiprolu { 363e76b7c01SSukadev Bhattiprolu struct pts_fs_info *fsi; 364e76b7c01SSukadev Bhattiprolu 365e76b7c01SSukadev Bhattiprolu fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL); 366e76b7c01SSukadev Bhattiprolu if (!fsi) 367e76b7c01SSukadev Bhattiprolu return NULL; 368e76b7c01SSukadev Bhattiprolu 369e76b7c01SSukadev Bhattiprolu ida_init(&fsi->allocated_ptys); 37031af0abbSSukadev Bhattiprolu fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE; 3711f8f1e29SSukadev Bhattiprolu fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; 372e76b7c01SSukadev Bhattiprolu 373e76b7c01SSukadev Bhattiprolu return fsi; 374e76b7c01SSukadev Bhattiprolu } 375e76b7c01SSukadev Bhattiprolu 3761da177e4SLinus Torvalds static int 3771da177e4SLinus Torvalds devpts_fill_super(struct super_block *s, void *data, int silent) 3781da177e4SLinus Torvalds { 3791da177e4SLinus Torvalds struct inode *inode; 3801da177e4SLinus Torvalds 3811da177e4SLinus Torvalds s->s_blocksize = 1024; 3821da177e4SLinus Torvalds s->s_blocksize_bits = 10; 3831da177e4SLinus Torvalds s->s_magic = DEVPTS_SUPER_MAGIC; 3841da177e4SLinus Torvalds s->s_op = &devpts_sops; 3851da177e4SLinus Torvalds s->s_time_gran = 1; 3861da177e4SLinus Torvalds 387e76b7c01SSukadev Bhattiprolu s->s_fs_info = new_pts_fs_info(); 388e76b7c01SSukadev Bhattiprolu if (!s->s_fs_info) 389e76b7c01SSukadev Bhattiprolu goto fail; 390e76b7c01SSukadev Bhattiprolu 3911da177e4SLinus Torvalds inode = new_inode(s); 3921da177e4SLinus Torvalds if (!inode) 3933850aba7SAl Viro goto fail; 3941da177e4SLinus Torvalds inode->i_ino = 1; 3951da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 3961da177e4SLinus Torvalds inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; 3971da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 3981da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 399bfe86848SMiklos Szeredi set_nlink(inode, 2); 4001da177e4SLinus Torvalds 40148fde701SAl Viro s->s_root = d_make_root(inode); 4021da177e4SLinus Torvalds if (s->s_root) 4031da177e4SLinus Torvalds return 0; 4041da177e4SLinus Torvalds 40504541a2fSFabian Frederick pr_err("get root dentry failed\n"); 406e76b7c01SSukadev Bhattiprolu 4071da177e4SLinus Torvalds fail: 4081da177e4SLinus Torvalds return -ENOMEM; 4091da177e4SLinus Torvalds } 4101da177e4SLinus Torvalds 4118c056e5bSAndrew Morton #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 412d4076ac5SSukadev Bhattiprolu static int compare_init_pts_sb(struct super_block *s, void *p) 413d4076ac5SSukadev Bhattiprolu { 414d4076ac5SSukadev Bhattiprolu if (devpts_mnt) 415d4076ac5SSukadev Bhattiprolu return devpts_mnt->mnt_sb == s; 4162a1b2dc0SSukadev Bhattiprolu return 0; 4172a1b2dc0SSukadev Bhattiprolu } 4182a1b2dc0SSukadev Bhattiprolu 4192a1b2dc0SSukadev Bhattiprolu /* 420fc14f2feSAl Viro * devpts_mount() 421289f00e2SSukadev Bhattiprolu * 4221bd79035SSukadev Bhattiprolu * If the '-o newinstance' mount option was specified, mount a new 4231bd79035SSukadev Bhattiprolu * (private) instance of devpts. PTYs created in this instance are 4241bd79035SSukadev Bhattiprolu * independent of the PTYs in other devpts instances. 425d4076ac5SSukadev Bhattiprolu * 4261bd79035SSukadev Bhattiprolu * If the '-o newinstance' option was not specified, mount/remount the 4271bd79035SSukadev Bhattiprolu * initial kernel mount of devpts. This type of mount gives the 4281bd79035SSukadev Bhattiprolu * legacy, single-instance semantics. 429d4076ac5SSukadev Bhattiprolu * 4301bd79035SSukadev Bhattiprolu * The 'newinstance' option is needed to support multiple namespace 4311bd79035SSukadev Bhattiprolu * semantics in devpts while preserving backward compatibility of the 4321bd79035SSukadev Bhattiprolu * current 'single-namespace' semantics. i.e all mounts of devpts 4331bd79035SSukadev Bhattiprolu * without the 'newinstance' mount option should bind to the initial 434fc14f2feSAl Viro * kernel mount, like mount_single(). 435d4076ac5SSukadev Bhattiprolu * 4361bd79035SSukadev Bhattiprolu * Mounts with 'newinstance' option create a new, private namespace. 4371bd79035SSukadev Bhattiprolu * 4381bd79035SSukadev Bhattiprolu * NOTE: 4391bd79035SSukadev Bhattiprolu * 440fc14f2feSAl Viro * For single-mount semantics, devpts cannot use mount_single(), 441fc14f2feSAl Viro * because mount_single()/sget() find and use the super-block from 442d4076ac5SSukadev Bhattiprolu * the most recent mount of devpts. But that recent mount may be a 443fc14f2feSAl Viro * 'newinstance' mount and mount_single() would pick the newinstance 444d4076ac5SSukadev Bhattiprolu * super-block instead of the initial super-block. 445d4076ac5SSukadev Bhattiprolu */ 446fc14f2feSAl Viro static struct dentry *devpts_mount(struct file_system_type *fs_type, 447fc14f2feSAl Viro int flags, const char *dev_name, void *data) 4481da177e4SLinus Torvalds { 449482984f0SSukadev Bhattiprolu int error; 450482984f0SSukadev Bhattiprolu struct pts_mount_opts opts; 4511bd79035SSukadev Bhattiprolu struct super_block *s; 4522a1b2dc0SSukadev Bhattiprolu 453482984f0SSukadev Bhattiprolu error = parse_mount_options(data, PARSE_MOUNT, &opts); 454482984f0SSukadev Bhattiprolu if (error) 455fc14f2feSAl Viro return ERR_PTR(error); 456482984f0SSukadev Bhattiprolu 457ec2aa8e8SEric W. Biederman /* Require newinstance for all user namespace mounts to ensure 458ec2aa8e8SEric W. Biederman * the mount options are not changed. 459ec2aa8e8SEric W. Biederman */ 460ec2aa8e8SEric W. Biederman if ((current_user_ns() != &init_user_ns) && !opts.newinstance) 461ec2aa8e8SEric W. Biederman return ERR_PTR(-EINVAL); 462ec2aa8e8SEric W. Biederman 463482984f0SSukadev Bhattiprolu if (opts.newinstance) 4649249e17fSDavid Howells s = sget(fs_type, NULL, set_anon_super, flags, NULL); 465482984f0SSukadev Bhattiprolu else 4669249e17fSDavid Howells s = sget(fs_type, compare_init_pts_sb, set_anon_super, flags, 4679249e17fSDavid Howells NULL); 468945cf2c7SSukadev Bhattiprolu 4691bd79035SSukadev Bhattiprolu if (IS_ERR(s)) 470fc14f2feSAl Viro return ERR_CAST(s); 4711bd79035SSukadev Bhattiprolu 4721bd79035SSukadev Bhattiprolu if (!s->s_root) { 4731bd79035SSukadev Bhattiprolu error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0); 474945cf2c7SSukadev Bhattiprolu if (error) 4751bd79035SSukadev Bhattiprolu goto out_undo_sget; 4761bd79035SSukadev Bhattiprolu s->s_flags |= MS_ACTIVE; 4771bd79035SSukadev Bhattiprolu } 478945cf2c7SSukadev Bhattiprolu 4791bd79035SSukadev Bhattiprolu memcpy(&(DEVPTS_SB(s))->mount_opts, &opts, sizeof(opts)); 4801bd79035SSukadev Bhattiprolu 4811bd79035SSukadev Bhattiprolu error = mknod_ptmx(s); 482945cf2c7SSukadev Bhattiprolu if (error) 48389468071SAl Viro goto out_undo_sget; 48489468071SAl Viro 485fc14f2feSAl Viro return dget(s->s_root); 486945cf2c7SSukadev Bhattiprolu 4871bd79035SSukadev Bhattiprolu out_undo_sget: 4886f5bbff9SAl Viro deactivate_locked_super(s); 489fc14f2feSAl Viro return ERR_PTR(error); 490482984f0SSukadev Bhattiprolu } 491482984f0SSukadev Bhattiprolu 4922a1b2dc0SSukadev Bhattiprolu #else 4932a1b2dc0SSukadev Bhattiprolu /* 4942a1b2dc0SSukadev Bhattiprolu * This supports only the legacy single-instance semantics (no 4952a1b2dc0SSukadev Bhattiprolu * multiple-instance semantics) 4962a1b2dc0SSukadev Bhattiprolu */ 497fc14f2feSAl Viro static struct dentry *devpts_mount(struct file_system_type *fs_type, int flags, 498fc14f2feSAl Viro const char *dev_name, void *data) 4992a1b2dc0SSukadev Bhattiprolu { 500fc14f2feSAl Viro return mount_single(fs_type, flags, data, devpts_fill_super); 5012a1b2dc0SSukadev Bhattiprolu } 5022a1b2dc0SSukadev Bhattiprolu #endif 5031da177e4SLinus Torvalds 504e76b7c01SSukadev Bhattiprolu static void devpts_kill_sb(struct super_block *sb) 505e76b7c01SSukadev Bhattiprolu { 506e76b7c01SSukadev Bhattiprolu struct pts_fs_info *fsi = DEVPTS_SB(sb); 507e76b7c01SSukadev Bhattiprolu 50866da0e1fSIlija Hadzic ida_destroy(&fsi->allocated_ptys); 509e76b7c01SSukadev Bhattiprolu kfree(fsi); 5101f8f1e29SSukadev Bhattiprolu kill_litter_super(sb); 511e76b7c01SSukadev Bhattiprolu } 512e76b7c01SSukadev Bhattiprolu 5131da177e4SLinus Torvalds static struct file_system_type devpts_fs_type = { 5141da177e4SLinus Torvalds .name = "devpts", 515fc14f2feSAl Viro .mount = devpts_mount, 516e76b7c01SSukadev Bhattiprolu .kill_sb = devpts_kill_sb, 517ec2aa8e8SEric W. Biederman #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES 518ec2aa8e8SEric W. Biederman .fs_flags = FS_USERNS_MOUNT | FS_USERNS_DEV_MOUNT, 519ec2aa8e8SEric W. Biederman #endif 5201da177e4SLinus Torvalds }; 5211da177e4SLinus Torvalds 5221da177e4SLinus Torvalds /* 5231da177e4SLinus Torvalds * The normal naming convention is simply /dev/pts/<number>; this conforms 5241da177e4SLinus Torvalds * to the System V naming convention 5251da177e4SLinus Torvalds */ 5261da177e4SLinus Torvalds 52715f1a633SSukadev Bhattiprolu int devpts_new_index(struct inode *ptmx_inode) 528718a9163SSukadev Bhattiprolu { 529e76b7c01SSukadev Bhattiprolu struct super_block *sb = pts_sb_from_inode(ptmx_inode); 5309ce71148SJosh Triplett struct pts_fs_info *fsi; 531718a9163SSukadev Bhattiprolu int index; 5327ee7c12bSAlexey Dobriyan int ida_ret; 533718a9163SSukadev Bhattiprolu 5349ce71148SJosh Triplett if (!sb) 5359ce71148SJosh Triplett return -ENODEV; 5369ce71148SJosh Triplett 5379ce71148SJosh Triplett fsi = DEVPTS_SB(sb); 538718a9163SSukadev Bhattiprolu retry: 539835aa440SAlan Cox if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) 540718a9163SSukadev Bhattiprolu return -ENOMEM; 541718a9163SSukadev Bhattiprolu 542718a9163SSukadev Bhattiprolu mutex_lock(&allocated_ptys_lock); 543e9aba515SKonstantin Khlebnikov if (pty_count >= pty_limit - 544e9aba515SKonstantin Khlebnikov (fsi->mount_opts.newinstance ? pty_reserve : 0)) { 545e9aba515SKonstantin Khlebnikov mutex_unlock(&allocated_ptys_lock); 546e9aba515SKonstantin Khlebnikov return -ENOSPC; 547e9aba515SKonstantin Khlebnikov } 548e9aba515SKonstantin Khlebnikov 549e76b7c01SSukadev Bhattiprolu ida_ret = ida_get_new(&fsi->allocated_ptys, &index); 5507ee7c12bSAlexey Dobriyan if (ida_ret < 0) { 551718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 5527ee7c12bSAlexey Dobriyan if (ida_ret == -EAGAIN) 553718a9163SSukadev Bhattiprolu goto retry; 554718a9163SSukadev Bhattiprolu return -EIO; 555718a9163SSukadev Bhattiprolu } 556718a9163SSukadev Bhattiprolu 557e9aba515SKonstantin Khlebnikov if (index >= fsi->mount_opts.max) { 558e76b7c01SSukadev Bhattiprolu ida_remove(&fsi->allocated_ptys, index); 559718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 560e9aba515SKonstantin Khlebnikov return -ENOSPC; 561718a9163SSukadev Bhattiprolu } 562a4834c10SKonstantin Khlebnikov pty_count++; 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); 574a4834c10SKonstantin Khlebnikov pty_count--; 575718a9163SSukadev Bhattiprolu mutex_unlock(&allocated_ptys_lock); 576718a9163SSukadev Bhattiprolu } 577718a9163SSukadev Bhattiprolu 5781dcb8e6dSJiri Slaby /** 5791dcb8e6dSJiri Slaby * devpts_pty_new -- create a new inode in /dev/pts/ 5801dcb8e6dSJiri Slaby * @ptmx_inode: inode of the master 5811dcb8e6dSJiri Slaby * @device: major+minor of the node to be created 5821dcb8e6dSJiri Slaby * @index: used as a name of the node 5831dcb8e6dSJiri Slaby * @priv: what's given back by devpts_get_priv 5841dcb8e6dSJiri Slaby * 5851dcb8e6dSJiri Slaby * The created inode is returned. Remove it from /dev/pts/ by devpts_pty_kill. 5861dcb8e6dSJiri Slaby */ 587f11afb61SJiri Slaby struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index, 588f11afb61SJiri Slaby void *priv) 5891da177e4SLinus Torvalds { 5901da177e4SLinus Torvalds struct dentry *dentry; 59159e55e6cSSukadev Bhattiprolu struct super_block *sb = pts_sb_from_inode(ptmx_inode); 592162b97cfSJiri Slaby struct inode *inode; 5939ce71148SJosh Triplett struct dentry *root; 5949ce71148SJosh Triplett struct pts_fs_info *fsi; 5959ce71148SJosh Triplett struct pts_mount_opts *opts; 59689a52e10SSukadev Bhattiprolu char s[12]; 5971da177e4SLinus Torvalds 5989ce71148SJosh Triplett if (!sb) 5999ce71148SJosh Triplett return ERR_PTR(-ENODEV); 6009ce71148SJosh Triplett 6019ce71148SJosh Triplett root = sb->s_root; 6029ce71148SJosh Triplett fsi = DEVPTS_SB(sb); 6039ce71148SJosh Triplett opts = &fsi->mount_opts; 6049ce71148SJosh Triplett 605162b97cfSJiri Slaby inode = new_inode(sb); 6061da177e4SLinus Torvalds if (!inode) 607162b97cfSJiri Slaby return ERR_PTR(-ENOMEM); 6081da177e4SLinus Torvalds 609f11afb61SJiri Slaby inode->i_ino = index + 3; 610d0eafc7dSDavid Howells inode->i_uid = opts->setuid ? opts->uid : current_fsuid(); 611d0eafc7dSDavid Howells inode->i_gid = opts->setgid ? opts->gid : current_fsgid(); 6121da177e4SLinus Torvalds inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 61331af0abbSSukadev Bhattiprolu init_special_inode(inode, S_IFCHR|opts->mode, device); 614f11afb61SJiri Slaby inode->i_private = priv; 6151da177e4SLinus Torvalds 616f11afb61SJiri Slaby sprintf(s, "%d", index); 61789a52e10SSukadev Bhattiprolu 6185955102cSAl Viro inode_lock(d_inode(root)); 61989a52e10SSukadev Bhattiprolu 62059e55e6cSSukadev Bhattiprolu dentry = d_alloc_name(root, s); 621b12d1259SAndrey Vagin if (dentry) { 62289a52e10SSukadev Bhattiprolu d_add(dentry, inode); 6232b0143b5SDavid Howells fsnotify_create(d_inode(root), dentry); 624aa597bc1SAndrey Vagin } else { 625aa597bc1SAndrey Vagin iput(inode); 626162b97cfSJiri Slaby inode = ERR_PTR(-ENOMEM); 6273972b7f6SFlorin Malita } 6281da177e4SLinus Torvalds 6295955102cSAl Viro inode_unlock(d_inode(root)); 6301da177e4SLinus Torvalds 631162b97cfSJiri Slaby return inode; 6321da177e4SLinus Torvalds } 6331da177e4SLinus Torvalds 6341dcb8e6dSJiri Slaby /** 6351dcb8e6dSJiri Slaby * devpts_get_priv -- get private data for a slave 6361dcb8e6dSJiri Slaby * @pts_inode: inode of the slave 6371dcb8e6dSJiri Slaby * 6381dcb8e6dSJiri Slaby * Returns whatever was passed as priv in devpts_pty_new for a given inode. 6391dcb8e6dSJiri Slaby */ 6408fcbaa2bSJiri Slaby void *devpts_get_priv(struct inode *pts_inode) 6411da177e4SLinus Torvalds { 642edfacdd6SSukadev Bhattiprolu struct dentry *dentry; 6438fcbaa2bSJiri Slaby void *priv = NULL; 644edfacdd6SSukadev Bhattiprolu 645527b3e47SSukadev Bhattiprolu BUG_ON(pts_inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); 6461da177e4SLinus Torvalds 647edfacdd6SSukadev Bhattiprolu /* Ensure dentry has not been deleted by devpts_pty_kill() */ 648edfacdd6SSukadev Bhattiprolu dentry = d_find_alias(pts_inode); 649edfacdd6SSukadev Bhattiprolu if (!dentry) 650527b3e47SSukadev Bhattiprolu return NULL; 651edfacdd6SSukadev Bhattiprolu 652edfacdd6SSukadev Bhattiprolu if (pts_inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) 6538fcbaa2bSJiri Slaby priv = pts_inode->i_private; 654edfacdd6SSukadev Bhattiprolu 655edfacdd6SSukadev Bhattiprolu dput(dentry); 656edfacdd6SSukadev Bhattiprolu 6578fcbaa2bSJiri Slaby return priv; 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 */ 666f11afb61SJiri Slaby void devpts_pty_kill(struct inode *inode) 6671da177e4SLinus Torvalds { 66859e55e6cSSukadev Bhattiprolu struct super_block *sb = pts_sb_from_inode(inode); 66959e55e6cSSukadev Bhattiprolu struct dentry *root = sb->s_root; 670a6f37daaSSukadev Bhattiprolu struct dentry *dentry; 6711da177e4SLinus Torvalds 672a6f37daaSSukadev Bhattiprolu BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); 673a6f37daaSSukadev Bhattiprolu 6745955102cSAl Viro inode_lock(d_inode(root)); 675a6f37daaSSukadev Bhattiprolu 676a6f37daaSSukadev Bhattiprolu dentry = d_find_alias(inode); 6772a1b2dc0SSukadev Bhattiprolu 6786d6b77f1SMiklos Szeredi drop_nlink(inode); 6791da177e4SLinus Torvalds d_delete(dentry); 680835aa440SAlan Cox dput(dentry); /* d_alloc_name() in devpts_pty_new() */ 681835aa440SAlan Cox dput(dentry); /* d_find_alias above */ 682aa597bc1SAndrey Vagin 6835955102cSAl Viro inode_unlock(d_inode(root)); 6841da177e4SLinus Torvalds } 6851da177e4SLinus Torvalds 6861da177e4SLinus Torvalds static int __init init_devpts_fs(void) 6871da177e4SLinus Torvalds { 6881da177e4SLinus Torvalds int err = register_filesystem(&devpts_fs_type); 689a4834c10SKonstantin Khlebnikov struct ctl_table_header *table; 690a4834c10SKonstantin Khlebnikov 6911da177e4SLinus Torvalds if (!err) { 6929ce71148SJosh Triplett struct vfsmount *mnt; 6939ce71148SJosh Triplett 694a4834c10SKonstantin Khlebnikov table = register_sysctl_table(pty_root_table); 6959ce71148SJosh Triplett mnt = kern_mount(&devpts_fs_type); 6969ce71148SJosh Triplett if (IS_ERR(mnt)) { 6979ce71148SJosh Triplett err = PTR_ERR(mnt); 69893d5581eSAlan Cox unregister_filesystem(&devpts_fs_type); 699a4834c10SKonstantin Khlebnikov unregister_sysctl_table(table); 7009ce71148SJosh Triplett } else { 7019ce71148SJosh Triplett devpts_mnt = mnt; 70293d5581eSAlan Cox } 7031da177e4SLinus Torvalds } 7041da177e4SLinus Torvalds return err; 7051da177e4SLinus Torvalds } 7061da177e4SLinus Torvalds module_init(init_devpts_fs) 707