Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/proc/inode.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/time.h> | |
8 | #include <linux/proc_fs.h> | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/mm.h> | |
11 | #include <linux/string.h> | |
12 | #include <linux/stat.h> | |
786d7e16 | 13 | #include <linux/completion.h> |
dd23aae4 | 14 | #include <linux/poll.h> |
1da177e4 LT |
15 | #include <linux/file.h> |
16 | #include <linux/limits.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/smp_lock.h> | |
20 | ||
21 | #include <asm/system.h> | |
22 | #include <asm/uaccess.h> | |
23 | ||
fee781e6 | 24 | #include "internal.h" |
1da177e4 | 25 | |
7695650a | 26 | struct proc_dir_entry *de_get(struct proc_dir_entry *de) |
1da177e4 | 27 | { |
5e971dce | 28 | atomic_inc(&de->count); |
1da177e4 LT |
29 | return de; |
30 | } | |
31 | ||
32 | /* | |
33 | * Decrements the use count and checks for deferred deletion. | |
34 | */ | |
7695650a | 35 | void de_put(struct proc_dir_entry *de) |
1da177e4 | 36 | { |
5e971dce AD |
37 | lock_kernel(); |
38 | if (!atomic_read(&de->count)) { | |
39 | printk("de_put: entry %s already free!\n", de->name); | |
1da177e4 | 40 | unlock_kernel(); |
5e971dce | 41 | return; |
1da177e4 | 42 | } |
5e971dce AD |
43 | |
44 | if (atomic_dec_and_test(&de->count)) | |
45 | free_proc_entry(de); | |
46 | unlock_kernel(); | |
1da177e4 LT |
47 | } |
48 | ||
49 | /* | |
50 | * Decrement the use count of the proc_dir_entry. | |
51 | */ | |
52 | static void proc_delete_inode(struct inode *inode) | |
53 | { | |
54 | struct proc_dir_entry *de; | |
1da177e4 | 55 | |
fef26658 MF |
56 | truncate_inode_pages(&inode->i_data, 0); |
57 | ||
99f89551 | 58 | /* Stop tracking associated processes */ |
13b41b09 | 59 | put_pid(PROC_I(inode)->pid); |
1da177e4 LT |
60 | |
61 | /* Let go of any associated proc directory entry */ | |
62 | de = PROC_I(inode)->pde; | |
63 | if (de) { | |
64 | if (de->owner) | |
65 | module_put(de->owner); | |
66 | de_put(de); | |
67 | } | |
68 | clear_inode(inode); | |
69 | } | |
70 | ||
71 | struct vfsmount *proc_mnt; | |
72 | ||
e18b890b | 73 | static struct kmem_cache * proc_inode_cachep; |
1da177e4 LT |
74 | |
75 | static struct inode *proc_alloc_inode(struct super_block *sb) | |
76 | { | |
77 | struct proc_inode *ei; | |
78 | struct inode *inode; | |
79 | ||
e94b1766 | 80 | ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
81 | if (!ei) |
82 | return NULL; | |
13b41b09 | 83 | ei->pid = NULL; |
aed7a6c4 | 84 | ei->fd = 0; |
1da177e4 LT |
85 | ei->op.proc_get_link = NULL; |
86 | ei->pde = NULL; | |
87 | inode = &ei->vfs_inode; | |
88 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
89 | return inode; | |
90 | } | |
91 | ||
92 | static void proc_destroy_inode(struct inode *inode) | |
93 | { | |
94 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); | |
95 | } | |
96 | ||
4ba9b9d0 | 97 | static void init_once(struct kmem_cache * cachep, void *foo) |
1da177e4 LT |
98 | { |
99 | struct proc_inode *ei = (struct proc_inode *) foo; | |
100 | ||
a35afb83 | 101 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 102 | } |
20c2df83 | 103 | |
1da177e4 LT |
104 | int __init proc_init_inodecache(void) |
105 | { | |
106 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
107 | sizeof(struct proc_inode), | |
fffb60f9 | 108 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 109 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 110 | init_once); |
1da177e4 LT |
111 | return 0; |
112 | } | |
113 | ||
ee9b6d61 | 114 | static const struct super_operations proc_sops = { |
1da177e4 LT |
115 | .alloc_inode = proc_alloc_inode, |
116 | .destroy_inode = proc_destroy_inode, | |
1da177e4 LT |
117 | .drop_inode = generic_delete_inode, |
118 | .delete_inode = proc_delete_inode, | |
119 | .statfs = simple_statfs, | |
1da177e4 LT |
120 | }; |
121 | ||
881adb85 | 122 | static void __pde_users_dec(struct proc_dir_entry *pde) |
786d7e16 | 123 | { |
786d7e16 AD |
124 | pde->pde_users--; |
125 | if (pde->pde_unload_completion && pde->pde_users == 0) | |
126 | complete(pde->pde_unload_completion); | |
881adb85 AD |
127 | } |
128 | ||
129 | static void pde_users_dec(struct proc_dir_entry *pde) | |
130 | { | |
131 | spin_lock(&pde->pde_unload_lock); | |
132 | __pde_users_dec(pde); | |
786d7e16 AD |
133 | spin_unlock(&pde->pde_unload_lock); |
134 | } | |
135 | ||
136 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) | |
137 | { | |
138 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
139 | loff_t rv = -EINVAL; | |
140 | loff_t (*llseek)(struct file *, loff_t, int); | |
141 | ||
142 | spin_lock(&pde->pde_unload_lock); | |
143 | /* | |
144 | * remove_proc_entry() is going to delete PDE (as part of module | |
145 | * cleanup sequence). No new callers into module allowed. | |
146 | */ | |
147 | if (!pde->proc_fops) { | |
148 | spin_unlock(&pde->pde_unload_lock); | |
149 | return rv; | |
150 | } | |
151 | /* | |
152 | * Bump refcount so that remove_proc_entry will wail for ->llseek to | |
153 | * complete. | |
154 | */ | |
155 | pde->pde_users++; | |
156 | /* | |
157 | * Save function pointer under lock, to protect against ->proc_fops | |
158 | * NULL'ifying right after ->pde_unload_lock is dropped. | |
159 | */ | |
160 | llseek = pde->proc_fops->llseek; | |
161 | spin_unlock(&pde->pde_unload_lock); | |
162 | ||
163 | if (!llseek) | |
164 | llseek = default_llseek; | |
165 | rv = llseek(file, offset, whence); | |
166 | ||
167 | pde_users_dec(pde); | |
168 | return rv; | |
169 | } | |
170 | ||
171 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
172 | { | |
173 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
174 | ssize_t rv = -EIO; | |
175 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); | |
176 | ||
177 | spin_lock(&pde->pde_unload_lock); | |
178 | if (!pde->proc_fops) { | |
179 | spin_unlock(&pde->pde_unload_lock); | |
180 | return rv; | |
181 | } | |
182 | pde->pde_users++; | |
183 | read = pde->proc_fops->read; | |
184 | spin_unlock(&pde->pde_unload_lock); | |
185 | ||
186 | if (read) | |
187 | rv = read(file, buf, count, ppos); | |
188 | ||
189 | pde_users_dec(pde); | |
190 | return rv; | |
191 | } | |
192 | ||
193 | static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
194 | { | |
195 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
196 | ssize_t rv = -EIO; | |
197 | ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); | |
198 | ||
199 | spin_lock(&pde->pde_unload_lock); | |
200 | if (!pde->proc_fops) { | |
201 | spin_unlock(&pde->pde_unload_lock); | |
202 | return rv; | |
203 | } | |
204 | pde->pde_users++; | |
205 | write = pde->proc_fops->write; | |
206 | spin_unlock(&pde->pde_unload_lock); | |
207 | ||
208 | if (write) | |
209 | rv = write(file, buf, count, ppos); | |
210 | ||
211 | pde_users_dec(pde); | |
212 | return rv; | |
213 | } | |
214 | ||
215 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
216 | { | |
217 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
dd23aae4 | 218 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 AD |
219 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
220 | ||
221 | spin_lock(&pde->pde_unload_lock); | |
222 | if (!pde->proc_fops) { | |
223 | spin_unlock(&pde->pde_unload_lock); | |
224 | return rv; | |
225 | } | |
226 | pde->pde_users++; | |
227 | poll = pde->proc_fops->poll; | |
228 | spin_unlock(&pde->pde_unload_lock); | |
229 | ||
230 | if (poll) | |
231 | rv = poll(file, pts); | |
232 | ||
233 | pde_users_dec(pde); | |
234 | return rv; | |
235 | } | |
236 | ||
237 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
238 | { | |
239 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
240 | long rv = -ENOTTY; | |
241 | long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long); | |
242 | int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long); | |
243 | ||
244 | spin_lock(&pde->pde_unload_lock); | |
245 | if (!pde->proc_fops) { | |
246 | spin_unlock(&pde->pde_unload_lock); | |
247 | return rv; | |
248 | } | |
249 | pde->pde_users++; | |
250 | unlocked_ioctl = pde->proc_fops->unlocked_ioctl; | |
251 | ioctl = pde->proc_fops->ioctl; | |
252 | spin_unlock(&pde->pde_unload_lock); | |
253 | ||
254 | if (unlocked_ioctl) { | |
255 | rv = unlocked_ioctl(file, cmd, arg); | |
256 | if (rv == -ENOIOCTLCMD) | |
257 | rv = -EINVAL; | |
258 | } else if (ioctl) { | |
259 | lock_kernel(); | |
260 | rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg); | |
261 | unlock_kernel(); | |
262 | } | |
263 | ||
264 | pde_users_dec(pde); | |
265 | return rv; | |
266 | } | |
267 | ||
268 | #ifdef CONFIG_COMPAT | |
269 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
270 | { | |
271 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
272 | long rv = -ENOTTY; | |
273 | long (*compat_ioctl)(struct file *, unsigned int, unsigned long); | |
274 | ||
275 | spin_lock(&pde->pde_unload_lock); | |
276 | if (!pde->proc_fops) { | |
277 | spin_unlock(&pde->pde_unload_lock); | |
278 | return rv; | |
279 | } | |
280 | pde->pde_users++; | |
281 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
282 | spin_unlock(&pde->pde_unload_lock); | |
283 | ||
284 | if (compat_ioctl) | |
285 | rv = compat_ioctl(file, cmd, arg); | |
286 | ||
287 | pde_users_dec(pde); | |
288 | return rv; | |
289 | } | |
290 | #endif | |
291 | ||
292 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
293 | { | |
294 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
295 | int rv = -EIO; | |
296 | int (*mmap)(struct file *, struct vm_area_struct *); | |
297 | ||
298 | spin_lock(&pde->pde_unload_lock); | |
299 | if (!pde->proc_fops) { | |
300 | spin_unlock(&pde->pde_unload_lock); | |
301 | return rv; | |
302 | } | |
303 | pde->pde_users++; | |
304 | mmap = pde->proc_fops->mmap; | |
305 | spin_unlock(&pde->pde_unload_lock); | |
306 | ||
307 | if (mmap) | |
308 | rv = mmap(file, vma); | |
309 | ||
310 | pde_users_dec(pde); | |
311 | return rv; | |
312 | } | |
313 | ||
314 | static int proc_reg_open(struct inode *inode, struct file *file) | |
315 | { | |
316 | struct proc_dir_entry *pde = PDE(inode); | |
317 | int rv = 0; | |
318 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
319 | int (*release)(struct inode *, struct file *); |
320 | struct pde_opener *pdeo; | |
321 | ||
322 | /* | |
323 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
324 | * sequence. ->release won't be called because ->proc_fops will be | |
325 | * cleared. Depending on complexity of ->release, consequences vary. | |
326 | * | |
327 | * We can't wait for mercy when close will be done for real, it's | |
328 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
329 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
330 | * for later. | |
331 | */ | |
332 | pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); | |
333 | if (!pdeo) | |
334 | return -ENOMEM; | |
786d7e16 AD |
335 | |
336 | spin_lock(&pde->pde_unload_lock); | |
337 | if (!pde->proc_fops) { | |
338 | spin_unlock(&pde->pde_unload_lock); | |
881adb85 | 339 | kfree(pdeo); |
786d7e16 AD |
340 | return rv; |
341 | } | |
342 | pde->pde_users++; | |
343 | open = pde->proc_fops->open; | |
881adb85 | 344 | release = pde->proc_fops->release; |
786d7e16 AD |
345 | spin_unlock(&pde->pde_unload_lock); |
346 | ||
347 | if (open) | |
348 | rv = open(inode, file); | |
349 | ||
881adb85 AD |
350 | spin_lock(&pde->pde_unload_lock); |
351 | if (rv == 0 && release) { | |
352 | /* To know what to release. */ | |
353 | pdeo->inode = inode; | |
354 | pdeo->file = file; | |
355 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
356 | pdeo->release = release; | |
357 | list_add(&pdeo->lh, &pde->pde_openers); | |
358 | } else | |
359 | kfree(pdeo); | |
360 | __pde_users_dec(pde); | |
361 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
362 | return rv; |
363 | } | |
364 | ||
881adb85 AD |
365 | static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
366 | struct inode *inode, struct file *file) | |
367 | { | |
368 | struct pde_opener *pdeo; | |
369 | ||
370 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { | |
371 | if (pdeo->inode == inode && pdeo->file == file) | |
372 | return pdeo; | |
373 | } | |
374 | return NULL; | |
375 | } | |
376 | ||
786d7e16 AD |
377 | static int proc_reg_release(struct inode *inode, struct file *file) |
378 | { | |
379 | struct proc_dir_entry *pde = PDE(inode); | |
380 | int rv = 0; | |
381 | int (*release)(struct inode *, struct file *); | |
881adb85 | 382 | struct pde_opener *pdeo; |
786d7e16 AD |
383 | |
384 | spin_lock(&pde->pde_unload_lock); | |
881adb85 | 385 | pdeo = find_pde_opener(pde, inode, file); |
786d7e16 | 386 | if (!pde->proc_fops) { |
881adb85 AD |
387 | /* |
388 | * Can't simply exit, __fput() will think that everything is OK, | |
389 | * and move on to freeing struct file. remove_proc_entry() will | |
390 | * find slacker in opener's list and will try to do non-trivial | |
391 | * things with struct file. Therefore, remove opener from list. | |
392 | * | |
393 | * But if opener is removed from list, who will ->release it? | |
394 | */ | |
395 | if (pdeo) { | |
396 | list_del(&pdeo->lh); | |
397 | spin_unlock(&pde->pde_unload_lock); | |
398 | rv = pdeo->release(inode, file); | |
399 | kfree(pdeo); | |
400 | } else | |
401 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
402 | return rv; |
403 | } | |
404 | pde->pde_users++; | |
405 | release = pde->proc_fops->release; | |
881adb85 AD |
406 | if (pdeo) { |
407 | list_del(&pdeo->lh); | |
408 | kfree(pdeo); | |
409 | } | |
786d7e16 AD |
410 | spin_unlock(&pde->pde_unload_lock); |
411 | ||
412 | if (release) | |
413 | rv = release(inode, file); | |
414 | ||
415 | pde_users_dec(pde); | |
416 | return rv; | |
417 | } | |
418 | ||
419 | static const struct file_operations proc_reg_file_ops = { | |
420 | .llseek = proc_reg_llseek, | |
421 | .read = proc_reg_read, | |
422 | .write = proc_reg_write, | |
423 | .poll = proc_reg_poll, | |
424 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
425 | #ifdef CONFIG_COMPAT | |
426 | .compat_ioctl = proc_reg_compat_ioctl, | |
427 | #endif | |
428 | .mmap = proc_reg_mmap, | |
429 | .open = proc_reg_open, | |
430 | .release = proc_reg_release, | |
431 | }; | |
432 | ||
778f3dd5 DM |
433 | #ifdef CONFIG_COMPAT |
434 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
435 | .llseek = proc_reg_llseek, | |
436 | .read = proc_reg_read, | |
437 | .write = proc_reg_write, | |
438 | .poll = proc_reg_poll, | |
439 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
440 | .mmap = proc_reg_mmap, | |
441 | .open = proc_reg_open, | |
442 | .release = proc_reg_release, | |
443 | }; | |
444 | #endif | |
445 | ||
1da177e4 LT |
446 | struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, |
447 | struct proc_dir_entry *de) | |
448 | { | |
449 | struct inode * inode; | |
450 | ||
5e971dce | 451 | if (!try_module_get(de->owner)) |
e9543659 KK |
452 | goto out_mod; |
453 | ||
a1d4aebb | 454 | inode = iget_locked(sb, ino); |
1da177e4 | 455 | if (!inode) |
e9543659 | 456 | goto out_ino; |
a1d4aebb DH |
457 | if (inode->i_state & I_NEW) { |
458 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
459 | PROC_I(inode)->fd = 0; | |
460 | PROC_I(inode)->pde = de; | |
5e971dce AD |
461 | |
462 | if (de->mode) { | |
463 | inode->i_mode = de->mode; | |
464 | inode->i_uid = de->uid; | |
465 | inode->i_gid = de->gid; | |
466 | } | |
467 | if (de->size) | |
468 | inode->i_size = de->size; | |
469 | if (de->nlink) | |
470 | inode->i_nlink = de->nlink; | |
471 | if (de->proc_iops) | |
472 | inode->i_op = de->proc_iops; | |
473 | if (de->proc_fops) { | |
474 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 475 | #ifdef CONFIG_COMPAT |
5e971dce AD |
476 | if (!de->proc_fops->compat_ioctl) |
477 | inode->i_fop = | |
478 | &proc_reg_file_ops_no_compat; | |
479 | else | |
778f3dd5 | 480 | #endif |
5e971dce AD |
481 | inode->i_fop = &proc_reg_file_ops; |
482 | } else { | |
483 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 484 | } |
786d7e16 | 485 | } |
a1d4aebb | 486 | unlock_new_inode(inode); |
c4185a0e DL |
487 | } else |
488 | module_put(de->owner); | |
1da177e4 LT |
489 | return inode; |
490 | ||
e9543659 | 491 | out_ino: |
5e971dce | 492 | module_put(de->owner); |
e9543659 | 493 | out_mod: |
e9543659 | 494 | return NULL; |
1da177e4 LT |
495 | } |
496 | ||
07543f5c | 497 | int proc_fill_super(struct super_block *s) |
1da177e4 LT |
498 | { |
499 | struct inode * root_inode; | |
500 | ||
92d03285 | 501 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
502 | s->s_blocksize = 1024; |
503 | s->s_blocksize_bits = 10; | |
504 | s->s_magic = PROC_SUPER_MAGIC; | |
505 | s->s_op = &proc_sops; | |
506 | s->s_time_gran = 1; | |
507 | ||
7695650a | 508 | de_get(&proc_root); |
1da177e4 LT |
509 | root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); |
510 | if (!root_inode) | |
511 | goto out_no_root; | |
1da177e4 LT |
512 | root_inode->i_uid = 0; |
513 | root_inode->i_gid = 0; | |
514 | s->s_root = d_alloc_root(root_inode); | |
515 | if (!s->s_root) | |
516 | goto out_no_root; | |
517 | return 0; | |
518 | ||
519 | out_no_root: | |
520 | printk("proc_read_super: get root inode failed\n"); | |
521 | iput(root_inode); | |
7695650a | 522 | de_put(&proc_root); |
1da177e4 LT |
523 | return -ENOMEM; |
524 | } |