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1da177e4 LT |
1 | /* -*- linux-c -*- --------------------------------------------------------- * |
2 | * | |
3 | * linux/fs/devpts/inode.c | |
4 | * | |
5 | * Copyright 1998-2004 H. Peter Anvin -- All Rights Reserved | |
6 | * | |
7 | * This file is part of the Linux kernel and is made available under | |
8 | * the terms of the GNU General Public License, version 2, or at your | |
9 | * option, any later version, incorporated herein by reference. | |
10 | * | |
11 | * ------------------------------------------------------------------------- */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/namei.h> | |
18 | #include <linux/mount.h> | |
19 | #include <linux/tty.h> | |
718a9163 | 20 | #include <linux/mutex.h> |
1fd7317d | 21 | #include <linux/magic.h> |
718a9163 | 22 | #include <linux/idr.h> |
1da177e4 | 23 | #include <linux/devpts_fs.h> |
7a673c6b | 24 | #include <linux/parser.h> |
3972b7f6 | 25 | #include <linux/fsnotify.h> |
b87a267e | 26 | #include <linux/seq_file.h> |
1da177e4 | 27 | |
b87a267e | 28 | #define DEVPTS_DEFAULT_MODE 0600 |
1f8f1e29 SB |
29 | /* |
30 | * ptmx is a new node in /dev/pts and will be unused in legacy (single- | |
31 | * instance) mode. To prevent surprises in user space, set permissions of | |
32 | * ptmx to 0. Use 'chmod' or remount with '-o ptmxmode' to set meaningful | |
33 | * permissions. | |
34 | */ | |
35 | #define DEVPTS_DEFAULT_PTMX_MODE 0000 | |
527b3e47 | 36 | #define PTMX_MINOR 2 |
b87a267e | 37 | |
718a9163 | 38 | extern int pty_limit; /* Config limit on Unix98 ptys */ |
718a9163 SB |
39 | static DEFINE_MUTEX(allocated_ptys_lock); |
40 | ||
1da177e4 | 41 | static struct vfsmount *devpts_mnt; |
1da177e4 | 42 | |
31af0abb | 43 | struct pts_mount_opts { |
1da177e4 LT |
44 | int setuid; |
45 | int setgid; | |
46 | uid_t uid; | |
47 | gid_t gid; | |
48 | umode_t mode; | |
1f8f1e29 | 49 | umode_t ptmxmode; |
2a1b2dc0 | 50 | int newinstance; |
31af0abb | 51 | }; |
1da177e4 | 52 | |
7a673c6b | 53 | enum { |
2a1b2dc0 | 54 | Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance, |
7a673c6b DP |
55 | Opt_err |
56 | }; | |
57 | ||
a447c093 | 58 | static const match_table_t tokens = { |
7a673c6b DP |
59 | {Opt_uid, "uid=%u"}, |
60 | {Opt_gid, "gid=%u"}, | |
61 | {Opt_mode, "mode=%o"}, | |
1f8f1e29 SB |
62 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
63 | {Opt_ptmxmode, "ptmxmode=%o"}, | |
2a1b2dc0 | 64 | {Opt_newinstance, "newinstance"}, |
1f8f1e29 | 65 | #endif |
7a673c6b DP |
66 | {Opt_err, NULL} |
67 | }; | |
68 | ||
e76b7c01 SB |
69 | struct pts_fs_info { |
70 | struct ida allocated_ptys; | |
31af0abb | 71 | struct pts_mount_opts mount_opts; |
1f8f1e29 | 72 | struct dentry *ptmx_dentry; |
e76b7c01 SB |
73 | }; |
74 | ||
75 | static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb) | |
76 | { | |
77 | return sb->s_fs_info; | |
78 | } | |
79 | ||
59e55e6c SB |
80 | static inline struct super_block *pts_sb_from_inode(struct inode *inode) |
81 | { | |
2a1b2dc0 | 82 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
59e55e6c SB |
83 | if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) |
84 | return inode->i_sb; | |
2a1b2dc0 | 85 | #endif |
59e55e6c SB |
86 | return devpts_mnt->mnt_sb; |
87 | } | |
88 | ||
2a1b2dc0 SB |
89 | #define PARSE_MOUNT 0 |
90 | #define PARSE_REMOUNT 1 | |
91 | ||
1f71ebed SB |
92 | /* |
93 | * parse_mount_options(): | |
94 | * Set @opts to mount options specified in @data. If an option is not | |
95 | * specified in @data, set it to its default value. The exception is | |
96 | * 'newinstance' option which can only be set/cleared on a mount (i.e. | |
97 | * cannot be changed during remount). | |
98 | * | |
99 | * Note: @data may be NULL (in which case all options are set to default). | |
100 | */ | |
2a1b2dc0 | 101 | static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) |
1da177e4 | 102 | { |
7a673c6b DP |
103 | char *p; |
104 | ||
31af0abb SB |
105 | opts->setuid = 0; |
106 | opts->setgid = 0; | |
107 | opts->uid = 0; | |
108 | opts->gid = 0; | |
109 | opts->mode = DEVPTS_DEFAULT_MODE; | |
1f8f1e29 | 110 | opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; |
7a673c6b | 111 | |
2a1b2dc0 SB |
112 | /* newinstance makes sense only on initial mount */ |
113 | if (op == PARSE_MOUNT) | |
114 | opts->newinstance = 0; | |
115 | ||
7a673c6b DP |
116 | while ((p = strsep(&data, ",")) != NULL) { |
117 | substring_t args[MAX_OPT_ARGS]; | |
118 | int token; | |
119 | int option; | |
120 | ||
121 | if (!*p) | |
1da177e4 | 122 | continue; |
7a673c6b DP |
123 | |
124 | token = match_token(p, tokens, args); | |
125 | switch (token) { | |
126 | case Opt_uid: | |
127 | if (match_int(&args[0], &option)) | |
128 | return -EINVAL; | |
31af0abb SB |
129 | opts->uid = option; |
130 | opts->setuid = 1; | |
7a673c6b DP |
131 | break; |
132 | case Opt_gid: | |
133 | if (match_int(&args[0], &option)) | |
134 | return -EINVAL; | |
31af0abb SB |
135 | opts->gid = option; |
136 | opts->setgid = 1; | |
7a673c6b DP |
137 | break; |
138 | case Opt_mode: | |
139 | if (match_octal(&args[0], &option)) | |
140 | return -EINVAL; | |
31af0abb | 141 | opts->mode = option & S_IALLUGO; |
7a673c6b | 142 | break; |
1f8f1e29 SB |
143 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
144 | case Opt_ptmxmode: | |
145 | if (match_octal(&args[0], &option)) | |
146 | return -EINVAL; | |
147 | opts->ptmxmode = option & S_IALLUGO; | |
148 | break; | |
2a1b2dc0 SB |
149 | case Opt_newinstance: |
150 | /* newinstance makes sense only on initial mount */ | |
151 | if (op == PARSE_MOUNT) | |
152 | opts->newinstance = 1; | |
153 | break; | |
1f8f1e29 | 154 | #endif |
7a673c6b DP |
155 | default: |
156 | printk(KERN_ERR "devpts: called with bogus options\n"); | |
1da177e4 LT |
157 | return -EINVAL; |
158 | } | |
159 | } | |
1da177e4 LT |
160 | |
161 | return 0; | |
162 | } | |
163 | ||
1f8f1e29 SB |
164 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
165 | static int mknod_ptmx(struct super_block *sb) | |
166 | { | |
167 | int mode; | |
168 | int rc = -ENOMEM; | |
169 | struct dentry *dentry; | |
170 | struct inode *inode; | |
171 | struct dentry *root = sb->s_root; | |
172 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
173 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
174 | ||
175 | mutex_lock(&root->d_inode->i_mutex); | |
176 | ||
177 | /* If we have already created ptmx node, return */ | |
178 | if (fsi->ptmx_dentry) { | |
179 | rc = 0; | |
180 | goto out; | |
181 | } | |
182 | ||
183 | dentry = d_alloc_name(root, "ptmx"); | |
184 | if (!dentry) { | |
185 | printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n"); | |
186 | goto out; | |
187 | } | |
188 | ||
189 | /* | |
190 | * Create a new 'ptmx' node in this mount of devpts. | |
191 | */ | |
192 | inode = new_inode(sb); | |
193 | if (!inode) { | |
194 | printk(KERN_ERR "Unable to alloc inode for ptmx node\n"); | |
195 | dput(dentry); | |
196 | goto out; | |
197 | } | |
198 | ||
199 | inode->i_ino = 2; | |
1f8f1e29 SB |
200 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
201 | ||
202 | mode = S_IFCHR|opts->ptmxmode; | |
203 | init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2)); | |
204 | ||
205 | d_add(dentry, inode); | |
206 | ||
207 | fsi->ptmx_dentry = dentry; | |
208 | rc = 0; | |
1f8f1e29 SB |
209 | out: |
210 | mutex_unlock(&root->d_inode->i_mutex); | |
211 | return rc; | |
212 | } | |
213 | ||
214 | static void update_ptmx_mode(struct pts_fs_info *fsi) | |
215 | { | |
216 | struct inode *inode; | |
217 | if (fsi->ptmx_dentry) { | |
218 | inode = fsi->ptmx_dentry->d_inode; | |
219 | inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode; | |
220 | } | |
221 | } | |
222 | #else | |
223 | static inline void update_ptmx_mode(struct pts_fs_info *fsi) | |
224 | { | |
225 | return; | |
226 | } | |
227 | #endif | |
228 | ||
53af8ee4 SB |
229 | static int devpts_remount(struct super_block *sb, int *flags, char *data) |
230 | { | |
1f8f1e29 | 231 | int err; |
53af8ee4 SB |
232 | struct pts_fs_info *fsi = DEVPTS_SB(sb); |
233 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
234 | ||
2a1b2dc0 | 235 | err = parse_mount_options(data, PARSE_REMOUNT, opts); |
1f8f1e29 SB |
236 | |
237 | /* | |
238 | * parse_mount_options() restores options to default values | |
239 | * before parsing and may have changed ptmxmode. So, update the | |
240 | * mode in the inode too. Bogus options don't fail the remount, | |
241 | * so do this even on error return. | |
242 | */ | |
243 | update_ptmx_mode(fsi); | |
244 | ||
245 | return err; | |
53af8ee4 SB |
246 | } |
247 | ||
b87a267e MS |
248 | static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs) |
249 | { | |
31af0abb SB |
250 | struct pts_fs_info *fsi = DEVPTS_SB(vfs->mnt_sb); |
251 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
252 | ||
253 | if (opts->setuid) | |
254 | seq_printf(seq, ",uid=%u", opts->uid); | |
255 | if (opts->setgid) | |
256 | seq_printf(seq, ",gid=%u", opts->gid); | |
257 | seq_printf(seq, ",mode=%03o", opts->mode); | |
1f8f1e29 SB |
258 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
259 | seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode); | |
260 | #endif | |
b87a267e MS |
261 | |
262 | return 0; | |
263 | } | |
264 | ||
ee9b6d61 | 265 | static const struct super_operations devpts_sops = { |
1da177e4 LT |
266 | .statfs = simple_statfs, |
267 | .remount_fs = devpts_remount, | |
b87a267e | 268 | .show_options = devpts_show_options, |
1da177e4 LT |
269 | }; |
270 | ||
e76b7c01 SB |
271 | static void *new_pts_fs_info(void) |
272 | { | |
273 | struct pts_fs_info *fsi; | |
274 | ||
275 | fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL); | |
276 | if (!fsi) | |
277 | return NULL; | |
278 | ||
279 | ida_init(&fsi->allocated_ptys); | |
31af0abb | 280 | fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE; |
1f8f1e29 | 281 | fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; |
e76b7c01 SB |
282 | |
283 | return fsi; | |
284 | } | |
285 | ||
1da177e4 LT |
286 | static int |
287 | devpts_fill_super(struct super_block *s, void *data, int silent) | |
288 | { | |
1f8f1e29 | 289 | struct inode *inode; |
1da177e4 LT |
290 | |
291 | s->s_blocksize = 1024; | |
292 | s->s_blocksize_bits = 10; | |
293 | s->s_magic = DEVPTS_SUPER_MAGIC; | |
294 | s->s_op = &devpts_sops; | |
1da177e4 LT |
295 | s->s_time_gran = 1; |
296 | ||
e76b7c01 SB |
297 | s->s_fs_info = new_pts_fs_info(); |
298 | if (!s->s_fs_info) | |
299 | goto fail; | |
300 | ||
1da177e4 LT |
301 | inode = new_inode(s); |
302 | if (!inode) | |
e76b7c01 | 303 | goto free_fsi; |
1da177e4 LT |
304 | inode->i_ino = 1; |
305 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
1da177e4 LT |
306 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; |
307 | inode->i_op = &simple_dir_inode_operations; | |
308 | inode->i_fop = &simple_dir_operations; | |
309 | inode->i_nlink = 2; | |
310 | ||
59e55e6c | 311 | s->s_root = d_alloc_root(inode); |
1da177e4 LT |
312 | if (s->s_root) |
313 | return 0; | |
1f8f1e29 | 314 | |
835aa440 | 315 | printk(KERN_ERR "devpts: get root dentry failed\n"); |
1da177e4 | 316 | iput(inode); |
e76b7c01 SB |
317 | |
318 | free_fsi: | |
319 | kfree(s->s_fs_info); | |
1da177e4 LT |
320 | fail: |
321 | return -ENOMEM; | |
322 | } | |
323 | ||
8c056e5b | 324 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
d4076ac5 SB |
325 | static int compare_init_pts_sb(struct super_block *s, void *p) |
326 | { | |
327 | if (devpts_mnt) | |
328 | return devpts_mnt->mnt_sb == s; | |
2a1b2dc0 SB |
329 | return 0; |
330 | } | |
331 | ||
2a1b2dc0 | 332 | /* |
1bd79035 SB |
333 | * devpts_get_sb() |
334 | * | |
335 | * If the '-o newinstance' mount option was specified, mount a new | |
336 | * (private) instance of devpts. PTYs created in this instance are | |
337 | * independent of the PTYs in other devpts instances. | |
338 | * | |
339 | * If the '-o newinstance' option was not specified, mount/remount the | |
340 | * initial kernel mount of devpts. This type of mount gives the | |
341 | * legacy, single-instance semantics. | |
289f00e2 | 342 | * |
1bd79035 SB |
343 | * The 'newinstance' option is needed to support multiple namespace |
344 | * semantics in devpts while preserving backward compatibility of the | |
345 | * current 'single-namespace' semantics. i.e all mounts of devpts | |
346 | * without the 'newinstance' mount option should bind to the initial | |
347 | * kernel mount, like get_sb_single(). | |
d4076ac5 | 348 | * |
1bd79035 | 349 | * Mounts with 'newinstance' option create a new, private namespace. |
d4076ac5 | 350 | * |
1bd79035 | 351 | * NOTE: |
d4076ac5 | 352 | * |
1bd79035 | 353 | * For single-mount semantics, devpts cannot use get_sb_single(), |
d4076ac5 SB |
354 | * because get_sb_single()/sget() find and use the super-block from |
355 | * the most recent mount of devpts. But that recent mount may be a | |
356 | * 'newinstance' mount and get_sb_single() would pick the newinstance | |
357 | * super-block instead of the initial super-block. | |
d4076ac5 | 358 | */ |
454e2398 DH |
359 | static int devpts_get_sb(struct file_system_type *fs_type, |
360 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 361 | { |
482984f0 SB |
362 | int error; |
363 | struct pts_mount_opts opts; | |
1bd79035 | 364 | struct super_block *s; |
2a1b2dc0 | 365 | |
1f71ebed SB |
366 | error = parse_mount_options(data, PARSE_MOUNT, &opts); |
367 | if (error) | |
368 | return error; | |
2a1b2dc0 | 369 | |
482984f0 | 370 | if (opts.newinstance) |
1bd79035 | 371 | s = sget(fs_type, NULL, set_anon_super, NULL); |
482984f0 | 372 | else |
1bd79035 | 373 | s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL); |
945cf2c7 | 374 | |
1bd79035 SB |
375 | if (IS_ERR(s)) |
376 | return PTR_ERR(s); | |
377 | ||
378 | if (!s->s_root) { | |
379 | s->s_flags = flags; | |
380 | error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0); | |
381 | if (error) | |
382 | goto out_undo_sget; | |
383 | s->s_flags |= MS_ACTIVE; | |
384 | } | |
385 | ||
386 | simple_set_mnt(mnt, s); | |
387 | ||
388 | memcpy(&(DEVPTS_SB(s))->mount_opts, &opts, sizeof(opts)); | |
945cf2c7 | 389 | |
1bd79035 | 390 | error = mknod_ptmx(s); |
945cf2c7 SB |
391 | if (error) |
392 | goto out_dput; | |
393 | ||
394 | return 0; | |
395 | ||
396 | out_dput: | |
6f5bbff9 | 397 | dput(s->s_root); /* undo dget() in simple_set_mnt() */ |
1bd79035 SB |
398 | |
399 | out_undo_sget: | |
6f5bbff9 | 400 | deactivate_locked_super(s); |
945cf2c7 | 401 | return error; |
1da177e4 | 402 | } |
482984f0 | 403 | |
2a1b2dc0 SB |
404 | #else |
405 | /* | |
406 | * This supports only the legacy single-instance semantics (no | |
407 | * multiple-instance semantics) | |
408 | */ | |
409 | static int devpts_get_sb(struct file_system_type *fs_type, int flags, | |
410 | const char *dev_name, void *data, struct vfsmount *mnt) | |
411 | { | |
412 | return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt); | |
413 | } | |
414 | #endif | |
1da177e4 | 415 | |
e76b7c01 SB |
416 | static void devpts_kill_sb(struct super_block *sb) |
417 | { | |
418 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
419 | ||
420 | kfree(fsi); | |
1f8f1e29 | 421 | kill_litter_super(sb); |
e76b7c01 SB |
422 | } |
423 | ||
1da177e4 | 424 | static struct file_system_type devpts_fs_type = { |
1da177e4 LT |
425 | .name = "devpts", |
426 | .get_sb = devpts_get_sb, | |
e76b7c01 | 427 | .kill_sb = devpts_kill_sb, |
1da177e4 LT |
428 | }; |
429 | ||
430 | /* | |
431 | * The normal naming convention is simply /dev/pts/<number>; this conforms | |
432 | * to the System V naming convention | |
433 | */ | |
434 | ||
15f1a633 | 435 | int devpts_new_index(struct inode *ptmx_inode) |
718a9163 | 436 | { |
e76b7c01 SB |
437 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
438 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
718a9163 | 439 | int index; |
7ee7c12b | 440 | int ida_ret; |
718a9163 SB |
441 | |
442 | retry: | |
835aa440 | 443 | if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) |
718a9163 | 444 | return -ENOMEM; |
718a9163 SB |
445 | |
446 | mutex_lock(&allocated_ptys_lock); | |
e76b7c01 | 447 | ida_ret = ida_get_new(&fsi->allocated_ptys, &index); |
7ee7c12b | 448 | if (ida_ret < 0) { |
718a9163 | 449 | mutex_unlock(&allocated_ptys_lock); |
7ee7c12b | 450 | if (ida_ret == -EAGAIN) |
718a9163 SB |
451 | goto retry; |
452 | return -EIO; | |
453 | } | |
454 | ||
455 | if (index >= pty_limit) { | |
e76b7c01 | 456 | ida_remove(&fsi->allocated_ptys, index); |
718a9163 SB |
457 | mutex_unlock(&allocated_ptys_lock); |
458 | return -EIO; | |
459 | } | |
460 | mutex_unlock(&allocated_ptys_lock); | |
461 | return index; | |
462 | } | |
463 | ||
15f1a633 | 464 | void devpts_kill_index(struct inode *ptmx_inode, int idx) |
718a9163 | 465 | { |
e76b7c01 SB |
466 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
467 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
468 | ||
718a9163 | 469 | mutex_lock(&allocated_ptys_lock); |
e76b7c01 | 470 | ida_remove(&fsi->allocated_ptys, idx); |
718a9163 SB |
471 | mutex_unlock(&allocated_ptys_lock); |
472 | } | |
473 | ||
15f1a633 | 474 | int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty) |
1da177e4 | 475 | { |
835aa440 AC |
476 | /* tty layer puts index from devpts_new_index() in here */ |
477 | int number = tty->index; | |
1da177e4 LT |
478 | struct tty_driver *driver = tty->driver; |
479 | dev_t device = MKDEV(driver->major, driver->minor_start+number); | |
480 | struct dentry *dentry; | |
59e55e6c SB |
481 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
482 | struct inode *inode = new_inode(sb); | |
483 | struct dentry *root = sb->s_root; | |
31af0abb SB |
484 | struct pts_fs_info *fsi = DEVPTS_SB(sb); |
485 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
89a52e10 | 486 | char s[12]; |
1da177e4 LT |
487 | |
488 | /* We're supposed to be given the slave end of a pty */ | |
489 | BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY); | |
490 | BUG_ON(driver->subtype != PTY_TYPE_SLAVE); | |
491 | ||
492 | if (!inode) | |
493 | return -ENOMEM; | |
494 | ||
d0eafc7d DH |
495 | inode->i_ino = number + 3; |
496 | inode->i_uid = opts->setuid ? opts->uid : current_fsuid(); | |
497 | inode->i_gid = opts->setgid ? opts->gid : current_fsgid(); | |
1da177e4 | 498 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
31af0abb | 499 | init_special_inode(inode, S_IFCHR|opts->mode, device); |
8e18e294 | 500 | inode->i_private = tty; |
a6f37daa | 501 | tty->driver_data = inode; |
1da177e4 | 502 | |
89a52e10 SB |
503 | sprintf(s, "%d", number); |
504 | ||
59e55e6c | 505 | mutex_lock(&root->d_inode->i_mutex); |
89a52e10 | 506 | |
59e55e6c | 507 | dentry = d_alloc_name(root, s); |
89a52e10 SB |
508 | if (!IS_ERR(dentry)) { |
509 | d_add(dentry, inode); | |
59e55e6c | 510 | fsnotify_create(root->d_inode, dentry); |
3972b7f6 | 511 | } |
1da177e4 | 512 | |
59e55e6c | 513 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
514 | |
515 | return 0; | |
516 | } | |
517 | ||
15f1a633 | 518 | struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number) |
1da177e4 | 519 | { |
527b3e47 | 520 | BUG_ON(pts_inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); |
1da177e4 | 521 | |
527b3e47 SB |
522 | if (pts_inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) |
523 | return (struct tty_struct *)pts_inode->i_private; | |
524 | return NULL; | |
1da177e4 LT |
525 | } |
526 | ||
15f1a633 | 527 | void devpts_pty_kill(struct tty_struct *tty) |
1da177e4 | 528 | { |
a6f37daa | 529 | struct inode *inode = tty->driver_data; |
59e55e6c SB |
530 | struct super_block *sb = pts_sb_from_inode(inode); |
531 | struct dentry *root = sb->s_root; | |
a6f37daa | 532 | struct dentry *dentry; |
1da177e4 | 533 | |
a6f37daa SB |
534 | BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); |
535 | ||
59e55e6c | 536 | mutex_lock(&root->d_inode->i_mutex); |
a6f37daa SB |
537 | |
538 | dentry = d_find_alias(inode); | |
2a1b2dc0 SB |
539 | if (IS_ERR(dentry)) |
540 | goto out; | |
541 | ||
542 | if (dentry) { | |
a6f37daa SB |
543 | inode->i_nlink--; |
544 | d_delete(dentry); | |
835aa440 | 545 | dput(dentry); /* d_alloc_name() in devpts_pty_new() */ |
1da177e4 | 546 | } |
a6f37daa | 547 | |
835aa440 | 548 | dput(dentry); /* d_find_alias above */ |
2a1b2dc0 | 549 | out: |
59e55e6c | 550 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
551 | } |
552 | ||
553 | static int __init init_devpts_fs(void) | |
554 | { | |
555 | int err = register_filesystem(&devpts_fs_type); | |
556 | if (!err) { | |
557 | devpts_mnt = kern_mount(&devpts_fs_type); | |
93d5581e | 558 | if (IS_ERR(devpts_mnt)) { |
1da177e4 | 559 | err = PTR_ERR(devpts_mnt); |
93d5581e AC |
560 | unregister_filesystem(&devpts_fs_type); |
561 | } | |
1da177e4 LT |
562 | } |
563 | return err; | |
564 | } | |
1da177e4 | 565 | module_init(init_devpts_fs) |