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; | |
99b76233 | 61 | if (de) |
1da177e4 | 62 | de_put(de); |
9043476f AV |
63 | if (PROC_I(inode)->sysctl) |
64 | sysctl_head_put(PROC_I(inode)->sysctl); | |
1da177e4 LT |
65 | clear_inode(inode); |
66 | } | |
67 | ||
68 | struct vfsmount *proc_mnt; | |
69 | ||
e18b890b | 70 | static struct kmem_cache * proc_inode_cachep; |
1da177e4 LT |
71 | |
72 | static struct inode *proc_alloc_inode(struct super_block *sb) | |
73 | { | |
74 | struct proc_inode *ei; | |
75 | struct inode *inode; | |
76 | ||
e94b1766 | 77 | ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
78 | if (!ei) |
79 | return NULL; | |
13b41b09 | 80 | ei->pid = NULL; |
aed7a6c4 | 81 | ei->fd = 0; |
1da177e4 LT |
82 | ei->op.proc_get_link = NULL; |
83 | ei->pde = NULL; | |
9043476f AV |
84 | ei->sysctl = NULL; |
85 | ei->sysctl_entry = NULL; | |
1da177e4 LT |
86 | inode = &ei->vfs_inode; |
87 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
88 | return inode; | |
89 | } | |
90 | ||
91 | static void proc_destroy_inode(struct inode *inode) | |
92 | { | |
93 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); | |
94 | } | |
95 | ||
51cc5068 | 96 | static void init_once(void *foo) |
1da177e4 LT |
97 | { |
98 | struct proc_inode *ei = (struct proc_inode *) foo; | |
99 | ||
a35afb83 | 100 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 101 | } |
20c2df83 | 102 | |
5bcd7ff9 | 103 | void __init proc_init_inodecache(void) |
1da177e4 LT |
104 | { |
105 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
106 | sizeof(struct proc_inode), | |
fffb60f9 | 107 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 108 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 109 | init_once); |
1da177e4 LT |
110 | } |
111 | ||
ee9b6d61 | 112 | static const struct super_operations proc_sops = { |
1da177e4 LT |
113 | .alloc_inode = proc_alloc_inode, |
114 | .destroy_inode = proc_destroy_inode, | |
1da177e4 LT |
115 | .drop_inode = generic_delete_inode, |
116 | .delete_inode = proc_delete_inode, | |
117 | .statfs = simple_statfs, | |
1da177e4 LT |
118 | }; |
119 | ||
881adb85 | 120 | static void __pde_users_dec(struct proc_dir_entry *pde) |
786d7e16 | 121 | { |
786d7e16 AD |
122 | pde->pde_users--; |
123 | if (pde->pde_unload_completion && pde->pde_users == 0) | |
124 | complete(pde->pde_unload_completion); | |
881adb85 AD |
125 | } |
126 | ||
3dec7f59 | 127 | void pde_users_dec(struct proc_dir_entry *pde) |
881adb85 AD |
128 | { |
129 | spin_lock(&pde->pde_unload_lock); | |
130 | __pde_users_dec(pde); | |
786d7e16 AD |
131 | spin_unlock(&pde->pde_unload_lock); |
132 | } | |
133 | ||
134 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) | |
135 | { | |
136 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
137 | loff_t rv = -EINVAL; | |
138 | loff_t (*llseek)(struct file *, loff_t, int); | |
139 | ||
140 | spin_lock(&pde->pde_unload_lock); | |
141 | /* | |
142 | * remove_proc_entry() is going to delete PDE (as part of module | |
143 | * cleanup sequence). No new callers into module allowed. | |
144 | */ | |
145 | if (!pde->proc_fops) { | |
146 | spin_unlock(&pde->pde_unload_lock); | |
147 | return rv; | |
148 | } | |
149 | /* | |
150 | * Bump refcount so that remove_proc_entry will wail for ->llseek to | |
151 | * complete. | |
152 | */ | |
153 | pde->pde_users++; | |
154 | /* | |
155 | * Save function pointer under lock, to protect against ->proc_fops | |
156 | * NULL'ifying right after ->pde_unload_lock is dropped. | |
157 | */ | |
158 | llseek = pde->proc_fops->llseek; | |
159 | spin_unlock(&pde->pde_unload_lock); | |
160 | ||
161 | if (!llseek) | |
162 | llseek = default_llseek; | |
163 | rv = llseek(file, offset, whence); | |
164 | ||
165 | pde_users_dec(pde); | |
166 | return rv; | |
167 | } | |
168 | ||
169 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
170 | { | |
171 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
172 | ssize_t rv = -EIO; | |
173 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); | |
174 | ||
175 | spin_lock(&pde->pde_unload_lock); | |
176 | if (!pde->proc_fops) { | |
177 | spin_unlock(&pde->pde_unload_lock); | |
178 | return rv; | |
179 | } | |
180 | pde->pde_users++; | |
181 | read = pde->proc_fops->read; | |
182 | spin_unlock(&pde->pde_unload_lock); | |
183 | ||
184 | if (read) | |
185 | rv = read(file, buf, count, ppos); | |
186 | ||
187 | pde_users_dec(pde); | |
188 | return rv; | |
189 | } | |
190 | ||
191 | static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
192 | { | |
193 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
194 | ssize_t rv = -EIO; | |
195 | ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); | |
196 | ||
197 | spin_lock(&pde->pde_unload_lock); | |
198 | if (!pde->proc_fops) { | |
199 | spin_unlock(&pde->pde_unload_lock); | |
200 | return rv; | |
201 | } | |
202 | pde->pde_users++; | |
203 | write = pde->proc_fops->write; | |
204 | spin_unlock(&pde->pde_unload_lock); | |
205 | ||
206 | if (write) | |
207 | rv = write(file, buf, count, ppos); | |
208 | ||
209 | pde_users_dec(pde); | |
210 | return rv; | |
211 | } | |
212 | ||
213 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
214 | { | |
215 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
dd23aae4 | 216 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 AD |
217 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
218 | ||
219 | spin_lock(&pde->pde_unload_lock); | |
220 | if (!pde->proc_fops) { | |
221 | spin_unlock(&pde->pde_unload_lock); | |
222 | return rv; | |
223 | } | |
224 | pde->pde_users++; | |
225 | poll = pde->proc_fops->poll; | |
226 | spin_unlock(&pde->pde_unload_lock); | |
227 | ||
228 | if (poll) | |
229 | rv = poll(file, pts); | |
230 | ||
231 | pde_users_dec(pde); | |
232 | return rv; | |
233 | } | |
234 | ||
235 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
236 | { | |
237 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
238 | long rv = -ENOTTY; | |
239 | long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long); | |
240 | int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long); | |
241 | ||
242 | spin_lock(&pde->pde_unload_lock); | |
243 | if (!pde->proc_fops) { | |
244 | spin_unlock(&pde->pde_unload_lock); | |
245 | return rv; | |
246 | } | |
247 | pde->pde_users++; | |
248 | unlocked_ioctl = pde->proc_fops->unlocked_ioctl; | |
249 | ioctl = pde->proc_fops->ioctl; | |
250 | spin_unlock(&pde->pde_unload_lock); | |
251 | ||
252 | if (unlocked_ioctl) { | |
253 | rv = unlocked_ioctl(file, cmd, arg); | |
254 | if (rv == -ENOIOCTLCMD) | |
255 | rv = -EINVAL; | |
256 | } else if (ioctl) { | |
257 | lock_kernel(); | |
258 | rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg); | |
259 | unlock_kernel(); | |
260 | } | |
261 | ||
262 | pde_users_dec(pde); | |
263 | return rv; | |
264 | } | |
265 | ||
266 | #ifdef CONFIG_COMPAT | |
267 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
268 | { | |
269 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
270 | long rv = -ENOTTY; | |
271 | long (*compat_ioctl)(struct file *, unsigned int, unsigned long); | |
272 | ||
273 | spin_lock(&pde->pde_unload_lock); | |
274 | if (!pde->proc_fops) { | |
275 | spin_unlock(&pde->pde_unload_lock); | |
276 | return rv; | |
277 | } | |
278 | pde->pde_users++; | |
279 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
280 | spin_unlock(&pde->pde_unload_lock); | |
281 | ||
282 | if (compat_ioctl) | |
283 | rv = compat_ioctl(file, cmd, arg); | |
284 | ||
285 | pde_users_dec(pde); | |
286 | return rv; | |
287 | } | |
288 | #endif | |
289 | ||
290 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
291 | { | |
292 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
293 | int rv = -EIO; | |
294 | int (*mmap)(struct file *, struct vm_area_struct *); | |
295 | ||
296 | spin_lock(&pde->pde_unload_lock); | |
297 | if (!pde->proc_fops) { | |
298 | spin_unlock(&pde->pde_unload_lock); | |
299 | return rv; | |
300 | } | |
301 | pde->pde_users++; | |
302 | mmap = pde->proc_fops->mmap; | |
303 | spin_unlock(&pde->pde_unload_lock); | |
304 | ||
305 | if (mmap) | |
306 | rv = mmap(file, vma); | |
307 | ||
308 | pde_users_dec(pde); | |
309 | return rv; | |
310 | } | |
311 | ||
312 | static int proc_reg_open(struct inode *inode, struct file *file) | |
313 | { | |
314 | struct proc_dir_entry *pde = PDE(inode); | |
315 | int rv = 0; | |
316 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
317 | int (*release)(struct inode *, struct file *); |
318 | struct pde_opener *pdeo; | |
319 | ||
320 | /* | |
321 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
322 | * sequence. ->release won't be called because ->proc_fops will be | |
323 | * cleared. Depending on complexity of ->release, consequences vary. | |
324 | * | |
325 | * We can't wait for mercy when close will be done for real, it's | |
326 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
327 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
328 | * for later. | |
329 | */ | |
330 | pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); | |
331 | if (!pdeo) | |
332 | return -ENOMEM; | |
786d7e16 AD |
333 | |
334 | spin_lock(&pde->pde_unload_lock); | |
335 | if (!pde->proc_fops) { | |
336 | spin_unlock(&pde->pde_unload_lock); | |
881adb85 | 337 | kfree(pdeo); |
300b994b | 338 | return -EINVAL; |
786d7e16 AD |
339 | } |
340 | pde->pde_users++; | |
341 | open = pde->proc_fops->open; | |
881adb85 | 342 | release = pde->proc_fops->release; |
786d7e16 AD |
343 | spin_unlock(&pde->pde_unload_lock); |
344 | ||
345 | if (open) | |
346 | rv = open(inode, file); | |
347 | ||
881adb85 AD |
348 | spin_lock(&pde->pde_unload_lock); |
349 | if (rv == 0 && release) { | |
350 | /* To know what to release. */ | |
351 | pdeo->inode = inode; | |
352 | pdeo->file = file; | |
353 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
354 | pdeo->release = release; | |
355 | list_add(&pdeo->lh, &pde->pde_openers); | |
356 | } else | |
357 | kfree(pdeo); | |
358 | __pde_users_dec(pde); | |
359 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
360 | return rv; |
361 | } | |
362 | ||
881adb85 AD |
363 | static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
364 | struct inode *inode, struct file *file) | |
365 | { | |
366 | struct pde_opener *pdeo; | |
367 | ||
368 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { | |
369 | if (pdeo->inode == inode && pdeo->file == file) | |
370 | return pdeo; | |
371 | } | |
372 | return NULL; | |
373 | } | |
374 | ||
786d7e16 AD |
375 | static int proc_reg_release(struct inode *inode, struct file *file) |
376 | { | |
377 | struct proc_dir_entry *pde = PDE(inode); | |
378 | int rv = 0; | |
379 | int (*release)(struct inode *, struct file *); | |
881adb85 | 380 | struct pde_opener *pdeo; |
786d7e16 AD |
381 | |
382 | spin_lock(&pde->pde_unload_lock); | |
881adb85 | 383 | pdeo = find_pde_opener(pde, inode, file); |
786d7e16 | 384 | if (!pde->proc_fops) { |
881adb85 AD |
385 | /* |
386 | * Can't simply exit, __fput() will think that everything is OK, | |
387 | * and move on to freeing struct file. remove_proc_entry() will | |
388 | * find slacker in opener's list and will try to do non-trivial | |
389 | * things with struct file. Therefore, remove opener from list. | |
390 | * | |
391 | * But if opener is removed from list, who will ->release it? | |
392 | */ | |
393 | if (pdeo) { | |
394 | list_del(&pdeo->lh); | |
395 | spin_unlock(&pde->pde_unload_lock); | |
396 | rv = pdeo->release(inode, file); | |
397 | kfree(pdeo); | |
398 | } else | |
399 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
400 | return rv; |
401 | } | |
402 | pde->pde_users++; | |
403 | release = pde->proc_fops->release; | |
881adb85 AD |
404 | if (pdeo) { |
405 | list_del(&pdeo->lh); | |
406 | kfree(pdeo); | |
407 | } | |
786d7e16 AD |
408 | spin_unlock(&pde->pde_unload_lock); |
409 | ||
410 | if (release) | |
411 | rv = release(inode, file); | |
412 | ||
413 | pde_users_dec(pde); | |
414 | return rv; | |
415 | } | |
416 | ||
417 | static const struct file_operations proc_reg_file_ops = { | |
418 | .llseek = proc_reg_llseek, | |
419 | .read = proc_reg_read, | |
420 | .write = proc_reg_write, | |
421 | .poll = proc_reg_poll, | |
422 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
423 | #ifdef CONFIG_COMPAT | |
424 | .compat_ioctl = proc_reg_compat_ioctl, | |
425 | #endif | |
426 | .mmap = proc_reg_mmap, | |
427 | .open = proc_reg_open, | |
428 | .release = proc_reg_release, | |
429 | }; | |
430 | ||
778f3dd5 DM |
431 | #ifdef CONFIG_COMPAT |
432 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
433 | .llseek = proc_reg_llseek, | |
434 | .read = proc_reg_read, | |
435 | .write = proc_reg_write, | |
436 | .poll = proc_reg_poll, | |
437 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
438 | .mmap = proc_reg_mmap, | |
439 | .open = proc_reg_open, | |
440 | .release = proc_reg_release, | |
441 | }; | |
442 | #endif | |
443 | ||
1da177e4 LT |
444 | struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, |
445 | struct proc_dir_entry *de) | |
446 | { | |
447 | struct inode * inode; | |
448 | ||
a1d4aebb | 449 | inode = iget_locked(sb, ino); |
1da177e4 | 450 | if (!inode) |
99b76233 | 451 | return NULL; |
a1d4aebb DH |
452 | if (inode->i_state & I_NEW) { |
453 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
454 | PROC_I(inode)->fd = 0; | |
455 | PROC_I(inode)->pde = de; | |
5e971dce AD |
456 | |
457 | if (de->mode) { | |
458 | inode->i_mode = de->mode; | |
459 | inode->i_uid = de->uid; | |
460 | inode->i_gid = de->gid; | |
461 | } | |
462 | if (de->size) | |
463 | inode->i_size = de->size; | |
464 | if (de->nlink) | |
465 | inode->i_nlink = de->nlink; | |
466 | if (de->proc_iops) | |
467 | inode->i_op = de->proc_iops; | |
468 | if (de->proc_fops) { | |
469 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 470 | #ifdef CONFIG_COMPAT |
5e971dce AD |
471 | if (!de->proc_fops->compat_ioctl) |
472 | inode->i_fop = | |
473 | &proc_reg_file_ops_no_compat; | |
474 | else | |
778f3dd5 | 475 | #endif |
5e971dce AD |
476 | inode->i_fop = &proc_reg_file_ops; |
477 | } else { | |
478 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 479 | } |
786d7e16 | 480 | } |
a1d4aebb | 481 | unlock_new_inode(inode); |
99b76233 | 482 | } else |
cac71121 | 483 | de_put(de); |
1da177e4 | 484 | return inode; |
1da177e4 LT |
485 | } |
486 | ||
07543f5c | 487 | int proc_fill_super(struct super_block *s) |
1da177e4 LT |
488 | { |
489 | struct inode * root_inode; | |
490 | ||
92d03285 | 491 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
492 | s->s_blocksize = 1024; |
493 | s->s_blocksize_bits = 10; | |
494 | s->s_magic = PROC_SUPER_MAGIC; | |
495 | s->s_op = &proc_sops; | |
496 | s->s_time_gran = 1; | |
497 | ||
7695650a | 498 | de_get(&proc_root); |
1da177e4 LT |
499 | root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); |
500 | if (!root_inode) | |
501 | goto out_no_root; | |
1da177e4 LT |
502 | root_inode->i_uid = 0; |
503 | root_inode->i_gid = 0; | |
504 | s->s_root = d_alloc_root(root_inode); | |
505 | if (!s->s_root) | |
506 | goto out_no_root; | |
507 | return 0; | |
508 | ||
509 | out_no_root: | |
510 | printk("proc_read_super: get root inode failed\n"); | |
511 | iput(root_inode); | |
7695650a | 512 | de_put(&proc_root); |
1da177e4 LT |
513 | return -ENOMEM; |
514 | } |