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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> | |
5a0e3ad6 | 18 | #include <linux/slab.h> |
1da177e4 LT |
19 | #include <linux/mount.h> |
20 | #include <linux/tty.h> | |
718a9163 | 21 | #include <linux/mutex.h> |
1fd7317d | 22 | #include <linux/magic.h> |
718a9163 | 23 | #include <linux/idr.h> |
1da177e4 | 24 | #include <linux/devpts_fs.h> |
7a673c6b | 25 | #include <linux/parser.h> |
3972b7f6 | 26 | #include <linux/fsnotify.h> |
b87a267e | 27 | #include <linux/seq_file.h> |
1da177e4 | 28 | |
b87a267e | 29 | #define DEVPTS_DEFAULT_MODE 0600 |
1f8f1e29 SB |
30 | /* |
31 | * ptmx is a new node in /dev/pts and will be unused in legacy (single- | |
32 | * instance) mode. To prevent surprises in user space, set permissions of | |
33 | * ptmx to 0. Use 'chmod' or remount with '-o ptmxmode' to set meaningful | |
34 | * permissions. | |
35 | */ | |
36 | #define DEVPTS_DEFAULT_PTMX_MODE 0000 | |
527b3e47 | 37 | #define PTMX_MINOR 2 |
b87a267e | 38 | |
718a9163 | 39 | extern int pty_limit; /* Config limit on Unix98 ptys */ |
718a9163 SB |
40 | static DEFINE_MUTEX(allocated_ptys_lock); |
41 | ||
1da177e4 | 42 | static struct vfsmount *devpts_mnt; |
1da177e4 | 43 | |
31af0abb | 44 | struct pts_mount_opts { |
1da177e4 LT |
45 | int setuid; |
46 | int setgid; | |
47 | uid_t uid; | |
48 | gid_t gid; | |
49 | umode_t mode; | |
1f8f1e29 | 50 | umode_t ptmxmode; |
2a1b2dc0 | 51 | int newinstance; |
31af0abb | 52 | }; |
1da177e4 | 53 | |
7a673c6b | 54 | enum { |
2a1b2dc0 | 55 | Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance, |
7a673c6b DP |
56 | Opt_err |
57 | }; | |
58 | ||
a447c093 | 59 | static const match_table_t tokens = { |
7a673c6b DP |
60 | {Opt_uid, "uid=%u"}, |
61 | {Opt_gid, "gid=%u"}, | |
62 | {Opt_mode, "mode=%o"}, | |
1f8f1e29 SB |
63 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
64 | {Opt_ptmxmode, "ptmxmode=%o"}, | |
2a1b2dc0 | 65 | {Opt_newinstance, "newinstance"}, |
1f8f1e29 | 66 | #endif |
7a673c6b DP |
67 | {Opt_err, NULL} |
68 | }; | |
69 | ||
e76b7c01 SB |
70 | struct pts_fs_info { |
71 | struct ida allocated_ptys; | |
31af0abb | 72 | struct pts_mount_opts mount_opts; |
1f8f1e29 | 73 | struct dentry *ptmx_dentry; |
e76b7c01 SB |
74 | }; |
75 | ||
76 | static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb) | |
77 | { | |
78 | return sb->s_fs_info; | |
79 | } | |
80 | ||
59e55e6c SB |
81 | static inline struct super_block *pts_sb_from_inode(struct inode *inode) |
82 | { | |
2a1b2dc0 | 83 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
59e55e6c SB |
84 | if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) |
85 | return inode->i_sb; | |
2a1b2dc0 | 86 | #endif |
59e55e6c SB |
87 | return devpts_mnt->mnt_sb; |
88 | } | |
89 | ||
2a1b2dc0 SB |
90 | #define PARSE_MOUNT 0 |
91 | #define PARSE_REMOUNT 1 | |
92 | ||
1f71ebed SB |
93 | /* |
94 | * parse_mount_options(): | |
95 | * Set @opts to mount options specified in @data. If an option is not | |
96 | * specified in @data, set it to its default value. The exception is | |
97 | * 'newinstance' option which can only be set/cleared on a mount (i.e. | |
98 | * cannot be changed during remount). | |
99 | * | |
100 | * Note: @data may be NULL (in which case all options are set to default). | |
101 | */ | |
2a1b2dc0 | 102 | static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) |
1da177e4 | 103 | { |
7a673c6b DP |
104 | char *p; |
105 | ||
31af0abb SB |
106 | opts->setuid = 0; |
107 | opts->setgid = 0; | |
108 | opts->uid = 0; | |
109 | opts->gid = 0; | |
110 | opts->mode = DEVPTS_DEFAULT_MODE; | |
1f8f1e29 | 111 | opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; |
7a673c6b | 112 | |
2a1b2dc0 SB |
113 | /* newinstance makes sense only on initial mount */ |
114 | if (op == PARSE_MOUNT) | |
115 | opts->newinstance = 0; | |
116 | ||
7a673c6b DP |
117 | while ((p = strsep(&data, ",")) != NULL) { |
118 | substring_t args[MAX_OPT_ARGS]; | |
119 | int token; | |
120 | int option; | |
121 | ||
122 | if (!*p) | |
1da177e4 | 123 | continue; |
7a673c6b DP |
124 | |
125 | token = match_token(p, tokens, args); | |
126 | switch (token) { | |
127 | case Opt_uid: | |
128 | if (match_int(&args[0], &option)) | |
129 | return -EINVAL; | |
31af0abb SB |
130 | opts->uid = option; |
131 | opts->setuid = 1; | |
7a673c6b DP |
132 | break; |
133 | case Opt_gid: | |
134 | if (match_int(&args[0], &option)) | |
135 | return -EINVAL; | |
31af0abb SB |
136 | opts->gid = option; |
137 | opts->setgid = 1; | |
7a673c6b DP |
138 | break; |
139 | case Opt_mode: | |
140 | if (match_octal(&args[0], &option)) | |
141 | return -EINVAL; | |
31af0abb | 142 | opts->mode = option & S_IALLUGO; |
7a673c6b | 143 | break; |
1f8f1e29 SB |
144 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
145 | case Opt_ptmxmode: | |
146 | if (match_octal(&args[0], &option)) | |
147 | return -EINVAL; | |
148 | opts->ptmxmode = option & S_IALLUGO; | |
149 | break; | |
2a1b2dc0 SB |
150 | case Opt_newinstance: |
151 | /* newinstance makes sense only on initial mount */ | |
152 | if (op == PARSE_MOUNT) | |
153 | opts->newinstance = 1; | |
154 | break; | |
1f8f1e29 | 155 | #endif |
7a673c6b DP |
156 | default: |
157 | printk(KERN_ERR "devpts: called with bogus options\n"); | |
1da177e4 LT |
158 | return -EINVAL; |
159 | } | |
160 | } | |
1da177e4 LT |
161 | |
162 | return 0; | |
163 | } | |
164 | ||
1f8f1e29 SB |
165 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
166 | static int mknod_ptmx(struct super_block *sb) | |
167 | { | |
168 | int mode; | |
169 | int rc = -ENOMEM; | |
170 | struct dentry *dentry; | |
171 | struct inode *inode; | |
172 | struct dentry *root = sb->s_root; | |
173 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
174 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
175 | ||
176 | mutex_lock(&root->d_inode->i_mutex); | |
177 | ||
178 | /* If we have already created ptmx node, return */ | |
179 | if (fsi->ptmx_dentry) { | |
180 | rc = 0; | |
181 | goto out; | |
182 | } | |
183 | ||
184 | dentry = d_alloc_name(root, "ptmx"); | |
185 | if (!dentry) { | |
186 | printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n"); | |
187 | goto out; | |
188 | } | |
189 | ||
190 | /* | |
191 | * Create a new 'ptmx' node in this mount of devpts. | |
192 | */ | |
193 | inode = new_inode(sb); | |
194 | if (!inode) { | |
195 | printk(KERN_ERR "Unable to alloc inode for ptmx node\n"); | |
196 | dput(dentry); | |
197 | goto out; | |
198 | } | |
199 | ||
200 | inode->i_ino = 2; | |
1f8f1e29 SB |
201 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
202 | ||
203 | mode = S_IFCHR|opts->ptmxmode; | |
204 | init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2)); | |
205 | ||
206 | d_add(dentry, inode); | |
207 | ||
208 | fsi->ptmx_dentry = dentry; | |
209 | rc = 0; | |
1f8f1e29 SB |
210 | out: |
211 | mutex_unlock(&root->d_inode->i_mutex); | |
212 | return rc; | |
213 | } | |
214 | ||
215 | static void update_ptmx_mode(struct pts_fs_info *fsi) | |
216 | { | |
217 | struct inode *inode; | |
218 | if (fsi->ptmx_dentry) { | |
219 | inode = fsi->ptmx_dentry->d_inode; | |
220 | inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode; | |
221 | } | |
222 | } | |
223 | #else | |
224 | static inline void update_ptmx_mode(struct pts_fs_info *fsi) | |
225 | { | |
226 | return; | |
227 | } | |
228 | #endif | |
229 | ||
53af8ee4 SB |
230 | static int devpts_remount(struct super_block *sb, int *flags, char *data) |
231 | { | |
1f8f1e29 | 232 | int err; |
53af8ee4 SB |
233 | struct pts_fs_info *fsi = DEVPTS_SB(sb); |
234 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
235 | ||
2a1b2dc0 | 236 | err = parse_mount_options(data, PARSE_REMOUNT, opts); |
1f8f1e29 SB |
237 | |
238 | /* | |
239 | * parse_mount_options() restores options to default values | |
240 | * before parsing and may have changed ptmxmode. So, update the | |
241 | * mode in the inode too. Bogus options don't fail the remount, | |
242 | * so do this even on error return. | |
243 | */ | |
244 | update_ptmx_mode(fsi); | |
245 | ||
246 | return err; | |
53af8ee4 SB |
247 | } |
248 | ||
b87a267e MS |
249 | static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs) |
250 | { | |
31af0abb SB |
251 | struct pts_fs_info *fsi = DEVPTS_SB(vfs->mnt_sb); |
252 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
253 | ||
254 | if (opts->setuid) | |
255 | seq_printf(seq, ",uid=%u", opts->uid); | |
256 | if (opts->setgid) | |
257 | seq_printf(seq, ",gid=%u", opts->gid); | |
258 | seq_printf(seq, ",mode=%03o", opts->mode); | |
1f8f1e29 SB |
259 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
260 | seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode); | |
261 | #endif | |
b87a267e MS |
262 | |
263 | return 0; | |
264 | } | |
265 | ||
ee9b6d61 | 266 | static const struct super_operations devpts_sops = { |
1da177e4 LT |
267 | .statfs = simple_statfs, |
268 | .remount_fs = devpts_remount, | |
b87a267e | 269 | .show_options = devpts_show_options, |
1da177e4 LT |
270 | }; |
271 | ||
e76b7c01 SB |
272 | static void *new_pts_fs_info(void) |
273 | { | |
274 | struct pts_fs_info *fsi; | |
275 | ||
276 | fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL); | |
277 | if (!fsi) | |
278 | return NULL; | |
279 | ||
280 | ida_init(&fsi->allocated_ptys); | |
31af0abb | 281 | fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE; |
1f8f1e29 | 282 | fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; |
e76b7c01 SB |
283 | |
284 | return fsi; | |
285 | } | |
286 | ||
1da177e4 LT |
287 | static int |
288 | devpts_fill_super(struct super_block *s, void *data, int silent) | |
289 | { | |
1f8f1e29 | 290 | struct inode *inode; |
1da177e4 LT |
291 | |
292 | s->s_blocksize = 1024; | |
293 | s->s_blocksize_bits = 10; | |
294 | s->s_magic = DEVPTS_SUPER_MAGIC; | |
295 | s->s_op = &devpts_sops; | |
1da177e4 LT |
296 | s->s_time_gran = 1; |
297 | ||
e76b7c01 SB |
298 | s->s_fs_info = new_pts_fs_info(); |
299 | if (!s->s_fs_info) | |
300 | goto fail; | |
301 | ||
1da177e4 LT |
302 | inode = new_inode(s); |
303 | if (!inode) | |
e76b7c01 | 304 | goto free_fsi; |
1da177e4 LT |
305 | inode->i_ino = 1; |
306 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
1da177e4 LT |
307 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; |
308 | inode->i_op = &simple_dir_inode_operations; | |
309 | inode->i_fop = &simple_dir_operations; | |
310 | inode->i_nlink = 2; | |
311 | ||
59e55e6c | 312 | s->s_root = d_alloc_root(inode); |
1da177e4 LT |
313 | if (s->s_root) |
314 | return 0; | |
1f8f1e29 | 315 | |
835aa440 | 316 | printk(KERN_ERR "devpts: get root dentry failed\n"); |
1da177e4 | 317 | iput(inode); |
e76b7c01 SB |
318 | |
319 | free_fsi: | |
320 | kfree(s->s_fs_info); | |
1da177e4 LT |
321 | fail: |
322 | return -ENOMEM; | |
323 | } | |
324 | ||
8c056e5b | 325 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
d4076ac5 SB |
326 | static int compare_init_pts_sb(struct super_block *s, void *p) |
327 | { | |
328 | if (devpts_mnt) | |
329 | return devpts_mnt->mnt_sb == s; | |
2a1b2dc0 SB |
330 | return 0; |
331 | } | |
332 | ||
2a1b2dc0 | 333 | /* |
1bd79035 SB |
334 | * devpts_get_sb() |
335 | * | |
336 | * If the '-o newinstance' mount option was specified, mount a new | |
337 | * (private) instance of devpts. PTYs created in this instance are | |
338 | * independent of the PTYs in other devpts instances. | |
339 | * | |
340 | * If the '-o newinstance' option was not specified, mount/remount the | |
341 | * initial kernel mount of devpts. This type of mount gives the | |
342 | * legacy, single-instance semantics. | |
289f00e2 | 343 | * |
1bd79035 SB |
344 | * The 'newinstance' option is needed to support multiple namespace |
345 | * semantics in devpts while preserving backward compatibility of the | |
346 | * current 'single-namespace' semantics. i.e all mounts of devpts | |
347 | * without the 'newinstance' mount option should bind to the initial | |
348 | * kernel mount, like get_sb_single(). | |
d4076ac5 | 349 | * |
1bd79035 | 350 | * Mounts with 'newinstance' option create a new, private namespace. |
d4076ac5 | 351 | * |
1bd79035 | 352 | * NOTE: |
d4076ac5 | 353 | * |
1bd79035 | 354 | * For single-mount semantics, devpts cannot use get_sb_single(), |
d4076ac5 SB |
355 | * because get_sb_single()/sget() find and use the super-block from |
356 | * the most recent mount of devpts. But that recent mount may be a | |
357 | * 'newinstance' mount and get_sb_single() would pick the newinstance | |
358 | * super-block instead of the initial super-block. | |
d4076ac5 | 359 | */ |
454e2398 DH |
360 | static int devpts_get_sb(struct file_system_type *fs_type, |
361 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 362 | { |
482984f0 SB |
363 | int error; |
364 | struct pts_mount_opts opts; | |
1bd79035 | 365 | struct super_block *s; |
2a1b2dc0 | 366 | |
1f71ebed SB |
367 | error = parse_mount_options(data, PARSE_MOUNT, &opts); |
368 | if (error) | |
369 | return error; | |
2a1b2dc0 | 370 | |
482984f0 | 371 | if (opts.newinstance) |
1bd79035 | 372 | s = sget(fs_type, NULL, set_anon_super, NULL); |
482984f0 | 373 | else |
1bd79035 | 374 | s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL); |
945cf2c7 | 375 | |
1bd79035 SB |
376 | if (IS_ERR(s)) |
377 | return PTR_ERR(s); | |
378 | ||
379 | if (!s->s_root) { | |
380 | s->s_flags = flags; | |
381 | error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0); | |
382 | if (error) | |
383 | goto out_undo_sget; | |
384 | s->s_flags |= MS_ACTIVE; | |
385 | } | |
386 | ||
1bd79035 | 387 | memcpy(&(DEVPTS_SB(s))->mount_opts, &opts, sizeof(opts)); |
945cf2c7 | 388 | |
1bd79035 | 389 | error = mknod_ptmx(s); |
945cf2c7 | 390 | if (error) |
89468071 | 391 | goto out_undo_sget; |
945cf2c7 | 392 | |
89468071 | 393 | simple_set_mnt(mnt, s); |
945cf2c7 | 394 | |
89468071 | 395 | return 0; |
1bd79035 SB |
396 | |
397 | out_undo_sget: | |
6f5bbff9 | 398 | deactivate_locked_super(s); |
945cf2c7 | 399 | return error; |
1da177e4 | 400 | } |
482984f0 | 401 | |
2a1b2dc0 SB |
402 | #else |
403 | /* | |
404 | * This supports only the legacy single-instance semantics (no | |
405 | * multiple-instance semantics) | |
406 | */ | |
407 | static int devpts_get_sb(struct file_system_type *fs_type, int flags, | |
408 | const char *dev_name, void *data, struct vfsmount *mnt) | |
409 | { | |
410 | return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt); | |
411 | } | |
412 | #endif | |
1da177e4 | 413 | |
e76b7c01 SB |
414 | static void devpts_kill_sb(struct super_block *sb) |
415 | { | |
416 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
417 | ||
418 | kfree(fsi); | |
1f8f1e29 | 419 | kill_litter_super(sb); |
e76b7c01 SB |
420 | } |
421 | ||
1da177e4 | 422 | static struct file_system_type devpts_fs_type = { |
1da177e4 LT |
423 | .name = "devpts", |
424 | .get_sb = devpts_get_sb, | |
e76b7c01 | 425 | .kill_sb = devpts_kill_sb, |
1da177e4 LT |
426 | }; |
427 | ||
428 | /* | |
429 | * The normal naming convention is simply /dev/pts/<number>; this conforms | |
430 | * to the System V naming convention | |
431 | */ | |
432 | ||
15f1a633 | 433 | int devpts_new_index(struct inode *ptmx_inode) |
718a9163 | 434 | { |
e76b7c01 SB |
435 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
436 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
718a9163 | 437 | int index; |
7ee7c12b | 438 | int ida_ret; |
718a9163 SB |
439 | |
440 | retry: | |
835aa440 | 441 | if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) |
718a9163 | 442 | return -ENOMEM; |
718a9163 SB |
443 | |
444 | mutex_lock(&allocated_ptys_lock); | |
e76b7c01 | 445 | ida_ret = ida_get_new(&fsi->allocated_ptys, &index); |
7ee7c12b | 446 | if (ida_ret < 0) { |
718a9163 | 447 | mutex_unlock(&allocated_ptys_lock); |
7ee7c12b | 448 | if (ida_ret == -EAGAIN) |
718a9163 SB |
449 | goto retry; |
450 | return -EIO; | |
451 | } | |
452 | ||
453 | if (index >= pty_limit) { | |
e76b7c01 | 454 | ida_remove(&fsi->allocated_ptys, index); |
718a9163 SB |
455 | mutex_unlock(&allocated_ptys_lock); |
456 | return -EIO; | |
457 | } | |
458 | mutex_unlock(&allocated_ptys_lock); | |
459 | return index; | |
460 | } | |
461 | ||
15f1a633 | 462 | void devpts_kill_index(struct inode *ptmx_inode, int idx) |
718a9163 | 463 | { |
e76b7c01 SB |
464 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
465 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
466 | ||
718a9163 | 467 | mutex_lock(&allocated_ptys_lock); |
e76b7c01 | 468 | ida_remove(&fsi->allocated_ptys, idx); |
718a9163 SB |
469 | mutex_unlock(&allocated_ptys_lock); |
470 | } | |
471 | ||
15f1a633 | 472 | int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty) |
1da177e4 | 473 | { |
835aa440 AC |
474 | /* tty layer puts index from devpts_new_index() in here */ |
475 | int number = tty->index; | |
1da177e4 LT |
476 | struct tty_driver *driver = tty->driver; |
477 | dev_t device = MKDEV(driver->major, driver->minor_start+number); | |
478 | struct dentry *dentry; | |
59e55e6c SB |
479 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
480 | struct inode *inode = new_inode(sb); | |
481 | struct dentry *root = sb->s_root; | |
31af0abb SB |
482 | struct pts_fs_info *fsi = DEVPTS_SB(sb); |
483 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
89a52e10 | 484 | char s[12]; |
1da177e4 LT |
485 | |
486 | /* We're supposed to be given the slave end of a pty */ | |
487 | BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY); | |
488 | BUG_ON(driver->subtype != PTY_TYPE_SLAVE); | |
489 | ||
490 | if (!inode) | |
491 | return -ENOMEM; | |
492 | ||
d0eafc7d DH |
493 | inode->i_ino = number + 3; |
494 | inode->i_uid = opts->setuid ? opts->uid : current_fsuid(); | |
495 | inode->i_gid = opts->setgid ? opts->gid : current_fsgid(); | |
1da177e4 | 496 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
31af0abb | 497 | init_special_inode(inode, S_IFCHR|opts->mode, device); |
8e18e294 | 498 | inode->i_private = tty; |
a6f37daa | 499 | tty->driver_data = inode; |
1da177e4 | 500 | |
89a52e10 SB |
501 | sprintf(s, "%d", number); |
502 | ||
59e55e6c | 503 | mutex_lock(&root->d_inode->i_mutex); |
89a52e10 | 504 | |
59e55e6c | 505 | dentry = d_alloc_name(root, s); |
89a52e10 SB |
506 | if (!IS_ERR(dentry)) { |
507 | d_add(dentry, inode); | |
59e55e6c | 508 | fsnotify_create(root->d_inode, dentry); |
3972b7f6 | 509 | } |
1da177e4 | 510 | |
59e55e6c | 511 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
512 | |
513 | return 0; | |
514 | } | |
515 | ||
15f1a633 | 516 | struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number) |
1da177e4 | 517 | { |
edfacdd6 SB |
518 | struct dentry *dentry; |
519 | struct tty_struct *tty; | |
520 | ||
527b3e47 | 521 | BUG_ON(pts_inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); |
1da177e4 | 522 | |
edfacdd6 SB |
523 | /* Ensure dentry has not been deleted by devpts_pty_kill() */ |
524 | dentry = d_find_alias(pts_inode); | |
525 | if (!dentry) | |
526 | return NULL; | |
527 | ||
528 | tty = NULL; | |
527b3e47 | 529 | if (pts_inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) |
edfacdd6 SB |
530 | tty = (struct tty_struct *)pts_inode->i_private; |
531 | ||
532 | dput(dentry); | |
533 | ||
534 | return tty; | |
1da177e4 LT |
535 | } |
536 | ||
15f1a633 | 537 | void devpts_pty_kill(struct tty_struct *tty) |
1da177e4 | 538 | { |
a6f37daa | 539 | struct inode *inode = tty->driver_data; |
59e55e6c SB |
540 | struct super_block *sb = pts_sb_from_inode(inode); |
541 | struct dentry *root = sb->s_root; | |
a6f37daa | 542 | struct dentry *dentry; |
1da177e4 | 543 | |
a6f37daa SB |
544 | BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); |
545 | ||
59e55e6c | 546 | mutex_lock(&root->d_inode->i_mutex); |
a6f37daa SB |
547 | |
548 | dentry = d_find_alias(inode); | |
2a1b2dc0 SB |
549 | if (IS_ERR(dentry)) |
550 | goto out; | |
551 | ||
552 | if (dentry) { | |
a6f37daa SB |
553 | inode->i_nlink--; |
554 | d_delete(dentry); | |
835aa440 | 555 | dput(dentry); /* d_alloc_name() in devpts_pty_new() */ |
1da177e4 | 556 | } |
a6f37daa | 557 | |
835aa440 | 558 | dput(dentry); /* d_find_alias above */ |
2a1b2dc0 | 559 | out: |
59e55e6c | 560 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
561 | } |
562 | ||
563 | static int __init init_devpts_fs(void) | |
564 | { | |
565 | int err = register_filesystem(&devpts_fs_type); | |
566 | if (!err) { | |
567 | devpts_mnt = kern_mount(&devpts_fs_type); | |
93d5581e | 568 | if (IS_ERR(devpts_mnt)) { |
1da177e4 | 569 | err = PTR_ERR(devpts_mnt); |
93d5581e AC |
570 | unregister_filesystem(&devpts_fs_type); |
571 | } | |
1da177e4 LT |
572 | } |
573 | return err; | |
574 | } | |
1da177e4 | 575 | module_init(init_devpts_fs) |