Commit | Line | Data |
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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 SB |
20 | #include <linux/mutex.h> |
21 | #include <linux/idr.h> | |
1da177e4 | 22 | #include <linux/devpts_fs.h> |
7a673c6b | 23 | #include <linux/parser.h> |
3972b7f6 | 24 | #include <linux/fsnotify.h> |
b87a267e | 25 | #include <linux/seq_file.h> |
1da177e4 LT |
26 | |
27 | #define DEVPTS_SUPER_MAGIC 0x1cd1 | |
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 | ||
93 | static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) | |
1da177e4 | 94 | { |
7a673c6b DP |
95 | char *p; |
96 | ||
31af0abb SB |
97 | opts->setuid = 0; |
98 | opts->setgid = 0; | |
99 | opts->uid = 0; | |
100 | opts->gid = 0; | |
101 | opts->mode = DEVPTS_DEFAULT_MODE; | |
1f8f1e29 | 102 | opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; |
7a673c6b | 103 | |
2a1b2dc0 SB |
104 | /* newinstance makes sense only on initial mount */ |
105 | if (op == PARSE_MOUNT) | |
106 | opts->newinstance = 0; | |
107 | ||
7a673c6b DP |
108 | while ((p = strsep(&data, ",")) != NULL) { |
109 | substring_t args[MAX_OPT_ARGS]; | |
110 | int token; | |
111 | int option; | |
112 | ||
113 | if (!*p) | |
1da177e4 | 114 | continue; |
7a673c6b DP |
115 | |
116 | token = match_token(p, tokens, args); | |
117 | switch (token) { | |
118 | case Opt_uid: | |
119 | if (match_int(&args[0], &option)) | |
120 | return -EINVAL; | |
31af0abb SB |
121 | opts->uid = option; |
122 | opts->setuid = 1; | |
7a673c6b DP |
123 | break; |
124 | case Opt_gid: | |
125 | if (match_int(&args[0], &option)) | |
126 | return -EINVAL; | |
31af0abb SB |
127 | opts->gid = option; |
128 | opts->setgid = 1; | |
7a673c6b DP |
129 | break; |
130 | case Opt_mode: | |
131 | if (match_octal(&args[0], &option)) | |
132 | return -EINVAL; | |
31af0abb | 133 | opts->mode = option & S_IALLUGO; |
7a673c6b | 134 | break; |
1f8f1e29 SB |
135 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
136 | case Opt_ptmxmode: | |
137 | if (match_octal(&args[0], &option)) | |
138 | return -EINVAL; | |
139 | opts->ptmxmode = option & S_IALLUGO; | |
140 | break; | |
2a1b2dc0 SB |
141 | case Opt_newinstance: |
142 | /* newinstance makes sense only on initial mount */ | |
143 | if (op == PARSE_MOUNT) | |
144 | opts->newinstance = 1; | |
145 | break; | |
1f8f1e29 | 146 | #endif |
7a673c6b DP |
147 | default: |
148 | printk(KERN_ERR "devpts: called with bogus options\n"); | |
1da177e4 LT |
149 | return -EINVAL; |
150 | } | |
151 | } | |
1da177e4 LT |
152 | |
153 | return 0; | |
154 | } | |
155 | ||
1f8f1e29 SB |
156 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
157 | static int mknod_ptmx(struct super_block *sb) | |
158 | { | |
159 | int mode; | |
160 | int rc = -ENOMEM; | |
161 | struct dentry *dentry; | |
162 | struct inode *inode; | |
163 | struct dentry *root = sb->s_root; | |
164 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
165 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
166 | ||
167 | mutex_lock(&root->d_inode->i_mutex); | |
168 | ||
169 | /* If we have already created ptmx node, return */ | |
170 | if (fsi->ptmx_dentry) { | |
171 | rc = 0; | |
172 | goto out; | |
173 | } | |
174 | ||
175 | dentry = d_alloc_name(root, "ptmx"); | |
176 | if (!dentry) { | |
177 | printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n"); | |
178 | goto out; | |
179 | } | |
180 | ||
181 | /* | |
182 | * Create a new 'ptmx' node in this mount of devpts. | |
183 | */ | |
184 | inode = new_inode(sb); | |
185 | if (!inode) { | |
186 | printk(KERN_ERR "Unable to alloc inode for ptmx node\n"); | |
187 | dput(dentry); | |
188 | goto out; | |
189 | } | |
190 | ||
191 | inode->i_ino = 2; | |
192 | inode->i_uid = inode->i_gid = 0; | |
193 | inode->i_blocks = 0; | |
194 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
195 | ||
196 | mode = S_IFCHR|opts->ptmxmode; | |
197 | init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2)); | |
198 | ||
199 | d_add(dentry, inode); | |
200 | ||
201 | fsi->ptmx_dentry = dentry; | |
202 | rc = 0; | |
203 | ||
204 | printk(KERN_DEBUG "Created ptmx node in devpts ino %lu\n", | |
205 | inode->i_ino); | |
206 | out: | |
207 | mutex_unlock(&root->d_inode->i_mutex); | |
208 | return rc; | |
209 | } | |
210 | ||
211 | static void update_ptmx_mode(struct pts_fs_info *fsi) | |
212 | { | |
213 | struct inode *inode; | |
214 | if (fsi->ptmx_dentry) { | |
215 | inode = fsi->ptmx_dentry->d_inode; | |
216 | inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode; | |
217 | } | |
218 | } | |
219 | #else | |
220 | static inline void update_ptmx_mode(struct pts_fs_info *fsi) | |
221 | { | |
222 | return; | |
223 | } | |
224 | #endif | |
225 | ||
53af8ee4 SB |
226 | static int devpts_remount(struct super_block *sb, int *flags, char *data) |
227 | { | |
1f8f1e29 | 228 | int err; |
53af8ee4 SB |
229 | struct pts_fs_info *fsi = DEVPTS_SB(sb); |
230 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
231 | ||
2a1b2dc0 | 232 | err = parse_mount_options(data, PARSE_REMOUNT, opts); |
1f8f1e29 SB |
233 | |
234 | /* | |
235 | * parse_mount_options() restores options to default values | |
236 | * before parsing and may have changed ptmxmode. So, update the | |
237 | * mode in the inode too. Bogus options don't fail the remount, | |
238 | * so do this even on error return. | |
239 | */ | |
240 | update_ptmx_mode(fsi); | |
241 | ||
242 | return err; | |
53af8ee4 SB |
243 | } |
244 | ||
b87a267e MS |
245 | static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs) |
246 | { | |
31af0abb SB |
247 | struct pts_fs_info *fsi = DEVPTS_SB(vfs->mnt_sb); |
248 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
249 | ||
250 | if (opts->setuid) | |
251 | seq_printf(seq, ",uid=%u", opts->uid); | |
252 | if (opts->setgid) | |
253 | seq_printf(seq, ",gid=%u", opts->gid); | |
254 | seq_printf(seq, ",mode=%03o", opts->mode); | |
1f8f1e29 SB |
255 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES |
256 | seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode); | |
257 | #endif | |
b87a267e MS |
258 | |
259 | return 0; | |
260 | } | |
261 | ||
ee9b6d61 | 262 | static const struct super_operations devpts_sops = { |
1da177e4 LT |
263 | .statfs = simple_statfs, |
264 | .remount_fs = devpts_remount, | |
b87a267e | 265 | .show_options = devpts_show_options, |
1da177e4 LT |
266 | }; |
267 | ||
e76b7c01 SB |
268 | static void *new_pts_fs_info(void) |
269 | { | |
270 | struct pts_fs_info *fsi; | |
271 | ||
272 | fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL); | |
273 | if (!fsi) | |
274 | return NULL; | |
275 | ||
276 | ida_init(&fsi->allocated_ptys); | |
31af0abb | 277 | fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE; |
1f8f1e29 | 278 | fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE; |
e76b7c01 SB |
279 | |
280 | return fsi; | |
281 | } | |
282 | ||
1da177e4 LT |
283 | static int |
284 | devpts_fill_super(struct super_block *s, void *data, int silent) | |
285 | { | |
1f8f1e29 | 286 | struct inode *inode; |
1da177e4 LT |
287 | |
288 | s->s_blocksize = 1024; | |
289 | s->s_blocksize_bits = 10; | |
290 | s->s_magic = DEVPTS_SUPER_MAGIC; | |
291 | s->s_op = &devpts_sops; | |
1da177e4 LT |
292 | s->s_time_gran = 1; |
293 | ||
e76b7c01 SB |
294 | s->s_fs_info = new_pts_fs_info(); |
295 | if (!s->s_fs_info) | |
296 | goto fail; | |
297 | ||
1da177e4 LT |
298 | inode = new_inode(s); |
299 | if (!inode) | |
e76b7c01 | 300 | goto free_fsi; |
1da177e4 LT |
301 | inode->i_ino = 1; |
302 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
303 | inode->i_blocks = 0; | |
1da177e4 LT |
304 | inode->i_uid = inode->i_gid = 0; |
305 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; | |
306 | inode->i_op = &simple_dir_inode_operations; | |
307 | inode->i_fop = &simple_dir_operations; | |
308 | inode->i_nlink = 2; | |
309 | ||
59e55e6c | 310 | s->s_root = d_alloc_root(inode); |
1da177e4 LT |
311 | if (s->s_root) |
312 | return 0; | |
1f8f1e29 | 313 | |
835aa440 | 314 | printk(KERN_ERR "devpts: get root dentry failed\n"); |
1da177e4 | 315 | iput(inode); |
e76b7c01 SB |
316 | |
317 | free_fsi: | |
318 | kfree(s->s_fs_info); | |
1da177e4 LT |
319 | fail: |
320 | return -ENOMEM; | |
321 | } | |
322 | ||
d4076ac5 SB |
323 | static int compare_init_pts_sb(struct super_block *s, void *p) |
324 | { | |
325 | if (devpts_mnt) | |
326 | return devpts_mnt->mnt_sb == s; | |
2a1b2dc0 SB |
327 | return 0; |
328 | } | |
329 | ||
330 | #ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES | |
331 | /* | |
332 | * Safely parse the mount options in @data and update @opts. | |
333 | * | |
334 | * devpts ends up parsing options two times during mount, due to the | |
335 | * two modes of operation it supports. The first parse occurs in | |
336 | * devpts_get_sb() when determining the mode (single-instance or | |
337 | * multi-instance mode). The second parse happens in devpts_remount() | |
338 | * or new_pts_mount() depending on the mode. | |
339 | * | |
340 | * Parsing of options modifies the @data making subsequent parsing | |
341 | * incorrect. So make a local copy of @data and parse it. | |
342 | * | |
343 | * Return: 0 On success, -errno on error | |
344 | */ | |
345 | static int safe_parse_mount_options(void *data, struct pts_mount_opts *opts) | |
346 | { | |
347 | int rc; | |
348 | void *datacp; | |
349 | ||
350 | if (!data) | |
351 | return 0; | |
352 | ||
353 | /* Use kstrdup() ? */ | |
354 | datacp = kmalloc(PAGE_SIZE, GFP_KERNEL); | |
355 | if (!datacp) | |
356 | return -ENOMEM; | |
357 | ||
358 | memcpy(datacp, data, PAGE_SIZE); | |
359 | rc = parse_mount_options((char *)datacp, PARSE_MOUNT, opts); | |
360 | kfree(datacp); | |
361 | ||
362 | return rc; | |
363 | } | |
364 | ||
365 | /* | |
366 | * Mount a new (private) instance of devpts. PTYs created in this | |
367 | * instance are independent of the PTYs in other devpts instances. | |
368 | */ | |
369 | static int new_pts_mount(struct file_system_type *fs_type, int flags, | |
370 | void *data, struct vfsmount *mnt) | |
371 | { | |
372 | int err; | |
373 | struct pts_fs_info *fsi; | |
374 | struct pts_mount_opts *opts; | |
375 | ||
376 | printk(KERN_NOTICE "devpts: newinstance mount\n"); | |
377 | ||
378 | err = get_sb_nodev(fs_type, flags, data, devpts_fill_super, mnt); | |
379 | if (err) | |
380 | return err; | |
381 | ||
382 | fsi = DEVPTS_SB(mnt->mnt_sb); | |
383 | opts = &fsi->mount_opts; | |
384 | ||
385 | err = parse_mount_options(data, PARSE_MOUNT, opts); | |
386 | if (err) | |
387 | goto fail; | |
388 | ||
389 | err = mknod_ptmx(mnt->mnt_sb); | |
390 | if (err) | |
391 | goto fail; | |
d4076ac5 SB |
392 | |
393 | return 0; | |
2a1b2dc0 SB |
394 | |
395 | fail: | |
396 | dput(mnt->mnt_sb->s_root); | |
397 | deactivate_super(mnt->mnt_sb); | |
398 | return err; | |
399 | } | |
400 | ||
401 | /* | |
402 | * Check if 'newinstance' mount option was specified in @data. | |
403 | * | |
404 | * Return: -errno on error (eg: invalid mount options specified) | |
405 | * : 1 if 'newinstance' mount option was specified | |
406 | * : 0 if 'newinstance' mount option was NOT specified | |
407 | */ | |
408 | static int is_new_instance_mount(void *data) | |
409 | { | |
410 | int rc; | |
411 | struct pts_mount_opts opts; | |
412 | ||
413 | if (!data) | |
414 | return 0; | |
415 | ||
416 | rc = safe_parse_mount_options(data, &opts); | |
417 | if (!rc) | |
418 | rc = opts.newinstance; | |
419 | ||
420 | return rc; | |
d4076ac5 SB |
421 | } |
422 | ||
423 | /* | |
424 | * get_init_pts_sb() | |
425 | * | |
426 | * This interface is needed to support multiple namespace semantics in | |
427 | * devpts while preserving backward compatibility of the current 'single- | |
428 | * namespace' semantics. i.e all mounts of devpts without the 'newinstance' | |
429 | * mount option should bind to the initial kernel mount, like | |
430 | * get_sb_single(). | |
431 | * | |
432 | * Mounts with 'newinstance' option create a new private namespace. | |
433 | * | |
434 | * But for single-mount semantics, devpts cannot use get_sb_single(), | |
435 | * because get_sb_single()/sget() find and use the super-block from | |
436 | * the most recent mount of devpts. But that recent mount may be a | |
437 | * 'newinstance' mount and get_sb_single() would pick the newinstance | |
438 | * super-block instead of the initial super-block. | |
439 | * | |
440 | * This interface is identical to get_sb_single() except that it | |
441 | * consistently selects the 'single-namespace' superblock even in the | |
442 | * presence of the private namespace (i.e 'newinstance') super-blocks. | |
443 | */ | |
444 | static int get_init_pts_sb(struct file_system_type *fs_type, int flags, | |
445 | void *data, struct vfsmount *mnt) | |
446 | { | |
835aa440 AC |
447 | struct super_block *s; |
448 | int error; | |
449 | ||
450 | s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL); | |
451 | if (IS_ERR(s)) | |
452 | return PTR_ERR(s); | |
453 | ||
454 | if (!s->s_root) { | |
455 | s->s_flags = flags; | |
456 | error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0); | |
457 | if (error) { | |
458 | up_write(&s->s_umount); | |
459 | deactivate_super(s); | |
460 | return error; | |
461 | } | |
462 | s->s_flags |= MS_ACTIVE; | |
463 | } | |
464 | do_remount_sb(s, flags, data, 0); | |
465 | return simple_set_mnt(mnt, s); | |
d4076ac5 SB |
466 | } |
467 | ||
2a1b2dc0 SB |
468 | /* |
469 | * Mount or remount the initial kernel mount of devpts. This type of | |
470 | * mount maintains the legacy, single-instance semantics, while the | |
471 | * kernel still allows multiple-instances. | |
472 | */ | |
473 | static int init_pts_mount(struct file_system_type *fs_type, int flags, | |
474 | void *data, struct vfsmount *mnt) | |
475 | { | |
476 | int err; | |
477 | ||
478 | err = get_init_pts_sb(fs_type, flags, data, mnt); | |
479 | if (err) | |
835aa440 | 480 | return err; |
2a1b2dc0 SB |
481 | |
482 | err = mknod_ptmx(mnt->mnt_sb); | |
483 | if (err) { | |
484 | dput(mnt->mnt_sb->s_root); | |
485 | deactivate_super(mnt->mnt_sb); | |
486 | } | |
487 | ||
488 | return err; | |
489 | } | |
490 | ||
454e2398 DH |
491 | static int devpts_get_sb(struct file_system_type *fs_type, |
492 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 493 | { |
2a1b2dc0 SB |
494 | int new; |
495 | ||
496 | new = is_new_instance_mount(data); | |
497 | if (new < 0) | |
498 | return new; | |
499 | ||
500 | if (new) | |
501 | return new_pts_mount(fs_type, flags, data, mnt); | |
502 | ||
503 | return init_pts_mount(fs_type, flags, data, mnt); | |
1da177e4 | 504 | } |
2a1b2dc0 SB |
505 | #else |
506 | /* | |
507 | * This supports only the legacy single-instance semantics (no | |
508 | * multiple-instance semantics) | |
509 | */ | |
510 | static int devpts_get_sb(struct file_system_type *fs_type, int flags, | |
511 | const char *dev_name, void *data, struct vfsmount *mnt) | |
512 | { | |
513 | return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt); | |
514 | } | |
515 | #endif | |
1da177e4 | 516 | |
e76b7c01 SB |
517 | static void devpts_kill_sb(struct super_block *sb) |
518 | { | |
519 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
520 | ||
521 | kfree(fsi); | |
1f8f1e29 | 522 | kill_litter_super(sb); |
e76b7c01 SB |
523 | } |
524 | ||
1da177e4 LT |
525 | static struct file_system_type devpts_fs_type = { |
526 | .owner = THIS_MODULE, | |
527 | .name = "devpts", | |
528 | .get_sb = devpts_get_sb, | |
e76b7c01 | 529 | .kill_sb = devpts_kill_sb, |
1da177e4 LT |
530 | }; |
531 | ||
532 | /* | |
533 | * The normal naming convention is simply /dev/pts/<number>; this conforms | |
534 | * to the System V naming convention | |
535 | */ | |
536 | ||
15f1a633 | 537 | int devpts_new_index(struct inode *ptmx_inode) |
718a9163 | 538 | { |
e76b7c01 SB |
539 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
540 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
718a9163 | 541 | int index; |
7ee7c12b | 542 | int ida_ret; |
718a9163 SB |
543 | |
544 | retry: | |
835aa440 | 545 | if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) |
718a9163 | 546 | return -ENOMEM; |
718a9163 SB |
547 | |
548 | mutex_lock(&allocated_ptys_lock); | |
e76b7c01 | 549 | ida_ret = ida_get_new(&fsi->allocated_ptys, &index); |
7ee7c12b | 550 | if (ida_ret < 0) { |
718a9163 | 551 | mutex_unlock(&allocated_ptys_lock); |
7ee7c12b | 552 | if (ida_ret == -EAGAIN) |
718a9163 SB |
553 | goto retry; |
554 | return -EIO; | |
555 | } | |
556 | ||
557 | if (index >= pty_limit) { | |
e76b7c01 | 558 | ida_remove(&fsi->allocated_ptys, index); |
718a9163 SB |
559 | mutex_unlock(&allocated_ptys_lock); |
560 | return -EIO; | |
561 | } | |
562 | mutex_unlock(&allocated_ptys_lock); | |
563 | return index; | |
564 | } | |
565 | ||
15f1a633 | 566 | void devpts_kill_index(struct inode *ptmx_inode, int idx) |
718a9163 | 567 | { |
e76b7c01 SB |
568 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
569 | struct pts_fs_info *fsi = DEVPTS_SB(sb); | |
570 | ||
718a9163 | 571 | mutex_lock(&allocated_ptys_lock); |
e76b7c01 | 572 | ida_remove(&fsi->allocated_ptys, idx); |
718a9163 SB |
573 | mutex_unlock(&allocated_ptys_lock); |
574 | } | |
575 | ||
15f1a633 | 576 | int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty) |
1da177e4 | 577 | { |
835aa440 AC |
578 | /* tty layer puts index from devpts_new_index() in here */ |
579 | int number = tty->index; | |
1da177e4 LT |
580 | struct tty_driver *driver = tty->driver; |
581 | dev_t device = MKDEV(driver->major, driver->minor_start+number); | |
582 | struct dentry *dentry; | |
59e55e6c SB |
583 | struct super_block *sb = pts_sb_from_inode(ptmx_inode); |
584 | struct inode *inode = new_inode(sb); | |
585 | struct dentry *root = sb->s_root; | |
31af0abb SB |
586 | struct pts_fs_info *fsi = DEVPTS_SB(sb); |
587 | struct pts_mount_opts *opts = &fsi->mount_opts; | |
89a52e10 | 588 | char s[12]; |
1da177e4 LT |
589 | |
590 | /* We're supposed to be given the slave end of a pty */ | |
591 | BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY); | |
592 | BUG_ON(driver->subtype != PTY_TYPE_SLAVE); | |
593 | ||
594 | if (!inode) | |
595 | return -ENOMEM; | |
596 | ||
597 | inode->i_ino = number+2; | |
ec4c2aac DH |
598 | inode->i_uid = config.setuid ? config.uid : current_fsuid(); |
599 | inode->i_gid = config.setgid ? config.gid : current_fsgid(); | |
1da177e4 | 600 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
31af0abb | 601 | init_special_inode(inode, S_IFCHR|opts->mode, device); |
8e18e294 | 602 | inode->i_private = tty; |
a6f37daa | 603 | tty->driver_data = inode; |
1da177e4 | 604 | |
89a52e10 SB |
605 | sprintf(s, "%d", number); |
606 | ||
59e55e6c | 607 | mutex_lock(&root->d_inode->i_mutex); |
89a52e10 | 608 | |
59e55e6c | 609 | dentry = d_alloc_name(root, s); |
89a52e10 SB |
610 | if (!IS_ERR(dentry)) { |
611 | d_add(dentry, inode); | |
59e55e6c | 612 | fsnotify_create(root->d_inode, dentry); |
3972b7f6 | 613 | } |
1da177e4 | 614 | |
59e55e6c | 615 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
616 | |
617 | return 0; | |
618 | } | |
619 | ||
15f1a633 | 620 | struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number) |
1da177e4 | 621 | { |
527b3e47 | 622 | BUG_ON(pts_inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); |
1da177e4 | 623 | |
527b3e47 SB |
624 | if (pts_inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC) |
625 | return (struct tty_struct *)pts_inode->i_private; | |
626 | return NULL; | |
1da177e4 LT |
627 | } |
628 | ||
15f1a633 | 629 | void devpts_pty_kill(struct tty_struct *tty) |
1da177e4 | 630 | { |
a6f37daa | 631 | struct inode *inode = tty->driver_data; |
59e55e6c SB |
632 | struct super_block *sb = pts_sb_from_inode(inode); |
633 | struct dentry *root = sb->s_root; | |
a6f37daa | 634 | struct dentry *dentry; |
1da177e4 | 635 | |
a6f37daa SB |
636 | BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR)); |
637 | ||
59e55e6c | 638 | mutex_lock(&root->d_inode->i_mutex); |
a6f37daa SB |
639 | |
640 | dentry = d_find_alias(inode); | |
2a1b2dc0 SB |
641 | if (IS_ERR(dentry)) |
642 | goto out; | |
643 | ||
644 | if (dentry) { | |
a6f37daa SB |
645 | inode->i_nlink--; |
646 | d_delete(dentry); | |
835aa440 | 647 | dput(dentry); /* d_alloc_name() in devpts_pty_new() */ |
1da177e4 | 648 | } |
a6f37daa | 649 | |
835aa440 | 650 | dput(dentry); /* d_find_alias above */ |
2a1b2dc0 | 651 | out: |
59e55e6c | 652 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
653 | } |
654 | ||
655 | static int __init init_devpts_fs(void) | |
656 | { | |
657 | int err = register_filesystem(&devpts_fs_type); | |
658 | if (!err) { | |
659 | devpts_mnt = kern_mount(&devpts_fs_type); | |
660 | if (IS_ERR(devpts_mnt)) | |
661 | err = PTR_ERR(devpts_mnt); | |
662 | } | |
663 | return err; | |
664 | } | |
665 | ||
666 | static void __exit exit_devpts_fs(void) | |
667 | { | |
668 | unregister_filesystem(&devpts_fs_type); | |
669 | mntput(devpts_mnt); | |
670 | } | |
671 | ||
672 | module_init(init_devpts_fs) | |
673 | module_exit(exit_devpts_fs) | |
674 | MODULE_LICENSE("GPL"); |