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> | |
9043476f | 20 | #include <linux/sysctl.h> |
1da177e4 LT |
21 | |
22 | #include <asm/system.h> | |
23 | #include <asm/uaccess.h> | |
24 | ||
fee781e6 | 25 | #include "internal.h" |
1da177e4 | 26 | |
7695650a | 27 | struct proc_dir_entry *de_get(struct proc_dir_entry *de) |
1da177e4 | 28 | { |
5e971dce | 29 | atomic_inc(&de->count); |
1da177e4 LT |
30 | return de; |
31 | } | |
32 | ||
33 | /* | |
34 | * Decrements the use count and checks for deferred deletion. | |
35 | */ | |
7695650a | 36 | void de_put(struct proc_dir_entry *de) |
1da177e4 | 37 | { |
5e971dce AD |
38 | if (!atomic_read(&de->count)) { |
39 | printk("de_put: entry %s already free!\n", de->name); | |
5e971dce | 40 | return; |
1da177e4 | 41 | } |
5e971dce AD |
42 | |
43 | if (atomic_dec_and_test(&de->count)) | |
44 | free_proc_entry(de); | |
1da177e4 LT |
45 | } |
46 | ||
47 | /* | |
48 | * Decrement the use count of the proc_dir_entry. | |
49 | */ | |
50 | static void proc_delete_inode(struct inode *inode) | |
51 | { | |
52 | struct proc_dir_entry *de; | |
1da177e4 | 53 | |
fef26658 MF |
54 | truncate_inode_pages(&inode->i_data, 0); |
55 | ||
99f89551 | 56 | /* Stop tracking associated processes */ |
13b41b09 | 57 | put_pid(PROC_I(inode)->pid); |
1da177e4 LT |
58 | |
59 | /* Let go of any associated proc directory entry */ | |
60 | de = PROC_I(inode)->pde; | |
61 | if (de) { | |
62 | if (de->owner) | |
63 | module_put(de->owner); | |
64 | de_put(de); | |
65 | } | |
9043476f AV |
66 | if (PROC_I(inode)->sysctl) |
67 | sysctl_head_put(PROC_I(inode)->sysctl); | |
1da177e4 LT |
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; | |
9043476f AV |
87 | ei->sysctl = NULL; |
88 | ei->sysctl_entry = NULL; | |
1da177e4 LT |
89 | inode = &ei->vfs_inode; |
90 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
91 | return inode; | |
92 | } | |
93 | ||
94 | static void proc_destroy_inode(struct inode *inode) | |
95 | { | |
96 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); | |
97 | } | |
98 | ||
51cc5068 | 99 | static void init_once(void *foo) |
1da177e4 LT |
100 | { |
101 | struct proc_inode *ei = (struct proc_inode *) foo; | |
102 | ||
a35afb83 | 103 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 104 | } |
20c2df83 | 105 | |
5bcd7ff9 | 106 | void __init proc_init_inodecache(void) |
1da177e4 LT |
107 | { |
108 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
109 | sizeof(struct proc_inode), | |
fffb60f9 | 110 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 111 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 112 | init_once); |
1da177e4 LT |
113 | } |
114 | ||
ee9b6d61 | 115 | static const struct super_operations proc_sops = { |
1da177e4 LT |
116 | .alloc_inode = proc_alloc_inode, |
117 | .destroy_inode = proc_destroy_inode, | |
1da177e4 LT |
118 | .drop_inode = generic_delete_inode, |
119 | .delete_inode = proc_delete_inode, | |
120 | .statfs = simple_statfs, | |
1da177e4 LT |
121 | }; |
122 | ||
881adb85 | 123 | static void __pde_users_dec(struct proc_dir_entry *pde) |
786d7e16 | 124 | { |
786d7e16 AD |
125 | pde->pde_users--; |
126 | if (pde->pde_unload_completion && pde->pde_users == 0) | |
127 | complete(pde->pde_unload_completion); | |
881adb85 AD |
128 | } |
129 | ||
130 | static void pde_users_dec(struct proc_dir_entry *pde) | |
131 | { | |
132 | spin_lock(&pde->pde_unload_lock); | |
133 | __pde_users_dec(pde); | |
786d7e16 AD |
134 | spin_unlock(&pde->pde_unload_lock); |
135 | } | |
136 | ||
137 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) | |
138 | { | |
139 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
140 | loff_t rv = -EINVAL; | |
141 | loff_t (*llseek)(struct file *, loff_t, int); | |
142 | ||
143 | spin_lock(&pde->pde_unload_lock); | |
144 | /* | |
145 | * remove_proc_entry() is going to delete PDE (as part of module | |
146 | * cleanup sequence). No new callers into module allowed. | |
147 | */ | |
148 | if (!pde->proc_fops) { | |
149 | spin_unlock(&pde->pde_unload_lock); | |
150 | return rv; | |
151 | } | |
152 | /* | |
153 | * Bump refcount so that remove_proc_entry will wail for ->llseek to | |
154 | * complete. | |
155 | */ | |
156 | pde->pde_users++; | |
157 | /* | |
158 | * Save function pointer under lock, to protect against ->proc_fops | |
159 | * NULL'ifying right after ->pde_unload_lock is dropped. | |
160 | */ | |
161 | llseek = pde->proc_fops->llseek; | |
162 | spin_unlock(&pde->pde_unload_lock); | |
163 | ||
164 | if (!llseek) | |
165 | llseek = default_llseek; | |
166 | rv = llseek(file, offset, whence); | |
167 | ||
168 | pde_users_dec(pde); | |
169 | return rv; | |
170 | } | |
171 | ||
172 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
173 | { | |
174 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
175 | ssize_t rv = -EIO; | |
176 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); | |
177 | ||
178 | spin_lock(&pde->pde_unload_lock); | |
179 | if (!pde->proc_fops) { | |
180 | spin_unlock(&pde->pde_unload_lock); | |
181 | return rv; | |
182 | } | |
183 | pde->pde_users++; | |
184 | read = pde->proc_fops->read; | |
185 | spin_unlock(&pde->pde_unload_lock); | |
186 | ||
187 | if (read) | |
188 | rv = read(file, buf, count, ppos); | |
189 | ||
190 | pde_users_dec(pde); | |
191 | return rv; | |
192 | } | |
193 | ||
194 | static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
195 | { | |
196 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
197 | ssize_t rv = -EIO; | |
198 | ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); | |
199 | ||
200 | spin_lock(&pde->pde_unload_lock); | |
201 | if (!pde->proc_fops) { | |
202 | spin_unlock(&pde->pde_unload_lock); | |
203 | return rv; | |
204 | } | |
205 | pde->pde_users++; | |
206 | write = pde->proc_fops->write; | |
207 | spin_unlock(&pde->pde_unload_lock); | |
208 | ||
209 | if (write) | |
210 | rv = write(file, buf, count, ppos); | |
211 | ||
212 | pde_users_dec(pde); | |
213 | return rv; | |
214 | } | |
215 | ||
216 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
217 | { | |
218 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
dd23aae4 | 219 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 AD |
220 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
221 | ||
222 | spin_lock(&pde->pde_unload_lock); | |
223 | if (!pde->proc_fops) { | |
224 | spin_unlock(&pde->pde_unload_lock); | |
225 | return rv; | |
226 | } | |
227 | pde->pde_users++; | |
228 | poll = pde->proc_fops->poll; | |
229 | spin_unlock(&pde->pde_unload_lock); | |
230 | ||
231 | if (poll) | |
232 | rv = poll(file, pts); | |
233 | ||
234 | pde_users_dec(pde); | |
235 | return rv; | |
236 | } | |
237 | ||
238 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
239 | { | |
240 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
241 | long rv = -ENOTTY; | |
242 | long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long); | |
243 | int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long); | |
244 | ||
245 | spin_lock(&pde->pde_unload_lock); | |
246 | if (!pde->proc_fops) { | |
247 | spin_unlock(&pde->pde_unload_lock); | |
248 | return rv; | |
249 | } | |
250 | pde->pde_users++; | |
251 | unlocked_ioctl = pde->proc_fops->unlocked_ioctl; | |
252 | ioctl = pde->proc_fops->ioctl; | |
253 | spin_unlock(&pde->pde_unload_lock); | |
254 | ||
255 | if (unlocked_ioctl) { | |
256 | rv = unlocked_ioctl(file, cmd, arg); | |
257 | if (rv == -ENOIOCTLCMD) | |
258 | rv = -EINVAL; | |
259 | } else if (ioctl) { | |
260 | lock_kernel(); | |
261 | rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg); | |
262 | unlock_kernel(); | |
263 | } | |
264 | ||
265 | pde_users_dec(pde); | |
266 | return rv; | |
267 | } | |
268 | ||
269 | #ifdef CONFIG_COMPAT | |
270 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
271 | { | |
272 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
273 | long rv = -ENOTTY; | |
274 | long (*compat_ioctl)(struct file *, unsigned int, unsigned long); | |
275 | ||
276 | spin_lock(&pde->pde_unload_lock); | |
277 | if (!pde->proc_fops) { | |
278 | spin_unlock(&pde->pde_unload_lock); | |
279 | return rv; | |
280 | } | |
281 | pde->pde_users++; | |
282 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
283 | spin_unlock(&pde->pde_unload_lock); | |
284 | ||
285 | if (compat_ioctl) | |
286 | rv = compat_ioctl(file, cmd, arg); | |
287 | ||
288 | pde_users_dec(pde); | |
289 | return rv; | |
290 | } | |
291 | #endif | |
292 | ||
293 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
294 | { | |
295 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
296 | int rv = -EIO; | |
297 | int (*mmap)(struct file *, struct vm_area_struct *); | |
298 | ||
299 | spin_lock(&pde->pde_unload_lock); | |
300 | if (!pde->proc_fops) { | |
301 | spin_unlock(&pde->pde_unload_lock); | |
302 | return rv; | |
303 | } | |
304 | pde->pde_users++; | |
305 | mmap = pde->proc_fops->mmap; | |
306 | spin_unlock(&pde->pde_unload_lock); | |
307 | ||
308 | if (mmap) | |
309 | rv = mmap(file, vma); | |
310 | ||
311 | pde_users_dec(pde); | |
312 | return rv; | |
313 | } | |
314 | ||
315 | static int proc_reg_open(struct inode *inode, struct file *file) | |
316 | { | |
317 | struct proc_dir_entry *pde = PDE(inode); | |
318 | int rv = 0; | |
319 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
320 | int (*release)(struct inode *, struct file *); |
321 | struct pde_opener *pdeo; | |
322 | ||
323 | /* | |
324 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
325 | * sequence. ->release won't be called because ->proc_fops will be | |
326 | * cleared. Depending on complexity of ->release, consequences vary. | |
327 | * | |
328 | * We can't wait for mercy when close will be done for real, it's | |
329 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
330 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
331 | * for later. | |
332 | */ | |
333 | pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); | |
334 | if (!pdeo) | |
335 | return -ENOMEM; | |
786d7e16 AD |
336 | |
337 | spin_lock(&pde->pde_unload_lock); | |
338 | if (!pde->proc_fops) { | |
339 | spin_unlock(&pde->pde_unload_lock); | |
881adb85 | 340 | kfree(pdeo); |
300b994b | 341 | return -EINVAL; |
786d7e16 AD |
342 | } |
343 | pde->pde_users++; | |
344 | open = pde->proc_fops->open; | |
881adb85 | 345 | release = pde->proc_fops->release; |
786d7e16 AD |
346 | spin_unlock(&pde->pde_unload_lock); |
347 | ||
348 | if (open) | |
349 | rv = open(inode, file); | |
350 | ||
881adb85 AD |
351 | spin_lock(&pde->pde_unload_lock); |
352 | if (rv == 0 && release) { | |
353 | /* To know what to release. */ | |
354 | pdeo->inode = inode; | |
355 | pdeo->file = file; | |
356 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
357 | pdeo->release = release; | |
358 | list_add(&pdeo->lh, &pde->pde_openers); | |
359 | } else | |
360 | kfree(pdeo); | |
361 | __pde_users_dec(pde); | |
362 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
363 | return rv; |
364 | } | |
365 | ||
881adb85 AD |
366 | static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
367 | struct inode *inode, struct file *file) | |
368 | { | |
369 | struct pde_opener *pdeo; | |
370 | ||
371 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { | |
372 | if (pdeo->inode == inode && pdeo->file == file) | |
373 | return pdeo; | |
374 | } | |
375 | return NULL; | |
376 | } | |
377 | ||
786d7e16 AD |
378 | static int proc_reg_release(struct inode *inode, struct file *file) |
379 | { | |
380 | struct proc_dir_entry *pde = PDE(inode); | |
381 | int rv = 0; | |
382 | int (*release)(struct inode *, struct file *); | |
881adb85 | 383 | struct pde_opener *pdeo; |
786d7e16 AD |
384 | |
385 | spin_lock(&pde->pde_unload_lock); | |
881adb85 | 386 | pdeo = find_pde_opener(pde, inode, file); |
786d7e16 | 387 | if (!pde->proc_fops) { |
881adb85 AD |
388 | /* |
389 | * Can't simply exit, __fput() will think that everything is OK, | |
390 | * and move on to freeing struct file. remove_proc_entry() will | |
391 | * find slacker in opener's list and will try to do non-trivial | |
392 | * things with struct file. Therefore, remove opener from list. | |
393 | * | |
394 | * But if opener is removed from list, who will ->release it? | |
395 | */ | |
396 | if (pdeo) { | |
397 | list_del(&pdeo->lh); | |
398 | spin_unlock(&pde->pde_unload_lock); | |
399 | rv = pdeo->release(inode, file); | |
400 | kfree(pdeo); | |
401 | } else | |
402 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
403 | return rv; |
404 | } | |
405 | pde->pde_users++; | |
406 | release = pde->proc_fops->release; | |
881adb85 AD |
407 | if (pdeo) { |
408 | list_del(&pdeo->lh); | |
409 | kfree(pdeo); | |
410 | } | |
786d7e16 AD |
411 | spin_unlock(&pde->pde_unload_lock); |
412 | ||
413 | if (release) | |
414 | rv = release(inode, file); | |
415 | ||
416 | pde_users_dec(pde); | |
417 | return rv; | |
418 | } | |
419 | ||
420 | static const struct file_operations proc_reg_file_ops = { | |
421 | .llseek = proc_reg_llseek, | |
422 | .read = proc_reg_read, | |
423 | .write = proc_reg_write, | |
424 | .poll = proc_reg_poll, | |
425 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
426 | #ifdef CONFIG_COMPAT | |
427 | .compat_ioctl = proc_reg_compat_ioctl, | |
428 | #endif | |
429 | .mmap = proc_reg_mmap, | |
430 | .open = proc_reg_open, | |
431 | .release = proc_reg_release, | |
432 | }; | |
433 | ||
778f3dd5 DM |
434 | #ifdef CONFIG_COMPAT |
435 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
436 | .llseek = proc_reg_llseek, | |
437 | .read = proc_reg_read, | |
438 | .write = proc_reg_write, | |
439 | .poll = proc_reg_poll, | |
440 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
441 | .mmap = proc_reg_mmap, | |
442 | .open = proc_reg_open, | |
443 | .release = proc_reg_release, | |
444 | }; | |
445 | #endif | |
446 | ||
1da177e4 LT |
447 | struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, |
448 | struct proc_dir_entry *de) | |
449 | { | |
450 | struct inode * inode; | |
451 | ||
5e971dce | 452 | if (!try_module_get(de->owner)) |
e9543659 KK |
453 | goto out_mod; |
454 | ||
a1d4aebb | 455 | inode = iget_locked(sb, ino); |
1da177e4 | 456 | if (!inode) |
e9543659 | 457 | goto out_ino; |
a1d4aebb DH |
458 | if (inode->i_state & I_NEW) { |
459 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
460 | PROC_I(inode)->fd = 0; | |
461 | PROC_I(inode)->pde = de; | |
5e971dce AD |
462 | |
463 | if (de->mode) { | |
464 | inode->i_mode = de->mode; | |
465 | inode->i_uid = de->uid; | |
466 | inode->i_gid = de->gid; | |
467 | } | |
468 | if (de->size) | |
469 | inode->i_size = de->size; | |
470 | if (de->nlink) | |
471 | inode->i_nlink = de->nlink; | |
472 | if (de->proc_iops) | |
473 | inode->i_op = de->proc_iops; | |
474 | if (de->proc_fops) { | |
475 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 476 | #ifdef CONFIG_COMPAT |
5e971dce AD |
477 | if (!de->proc_fops->compat_ioctl) |
478 | inode->i_fop = | |
479 | &proc_reg_file_ops_no_compat; | |
480 | else | |
778f3dd5 | 481 | #endif |
5e971dce AD |
482 | inode->i_fop = &proc_reg_file_ops; |
483 | } else { | |
484 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 485 | } |
786d7e16 | 486 | } |
a1d4aebb | 487 | unlock_new_inode(inode); |
cac71121 | 488 | } else { |
c4185a0e | 489 | module_put(de->owner); |
cac71121 KS |
490 | de_put(de); |
491 | } | |
1da177e4 LT |
492 | return inode; |
493 | ||
e9543659 | 494 | out_ino: |
5e971dce | 495 | module_put(de->owner); |
e9543659 | 496 | out_mod: |
e9543659 | 497 | return NULL; |
1da177e4 LT |
498 | } |
499 | ||
07543f5c | 500 | int proc_fill_super(struct super_block *s) |
1da177e4 LT |
501 | { |
502 | struct inode * root_inode; | |
503 | ||
92d03285 | 504 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
505 | s->s_blocksize = 1024; |
506 | s->s_blocksize_bits = 10; | |
507 | s->s_magic = PROC_SUPER_MAGIC; | |
508 | s->s_op = &proc_sops; | |
509 | s->s_time_gran = 1; | |
510 | ||
7695650a | 511 | de_get(&proc_root); |
1da177e4 LT |
512 | root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); |
513 | if (!root_inode) | |
514 | goto out_no_root; | |
1da177e4 LT |
515 | root_inode->i_uid = 0; |
516 | root_inode->i_gid = 0; | |
517 | s->s_root = d_alloc_root(root_inode); | |
518 | if (!s->s_root) | |
519 | goto out_no_root; | |
520 | return 0; | |
521 | ||
522 | out_no_root: | |
523 | printk("proc_read_super: get root inode failed\n"); | |
524 | iput(root_inode); | |
7695650a | 525 | de_put(&proc_root); |
1da177e4 LT |
526 | return -ENOMEM; |
527 | } |