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> | |
9043476f | 19 | #include <linux/sysctl.h> |
5a0e3ad6 | 20 | #include <linux/slab.h> |
1da177e4 LT |
21 | |
22 | #include <asm/system.h> | |
23 | #include <asm/uaccess.h> | |
24 | ||
fee781e6 | 25 | #include "internal.h" |
1da177e4 | 26 | |
8267952b | 27 | static void proc_evict_inode(struct inode *inode) |
1da177e4 LT |
28 | { |
29 | struct proc_dir_entry *de; | |
dfef6dcd | 30 | struct ctl_table_header *head; |
6b4e306a | 31 | const struct proc_ns_operations *ns_ops; |
1da177e4 | 32 | |
fef26658 | 33 | truncate_inode_pages(&inode->i_data, 0); |
8267952b | 34 | end_writeback(inode); |
fef26658 | 35 | |
99f89551 | 36 | /* Stop tracking associated processes */ |
13b41b09 | 37 | put_pid(PROC_I(inode)->pid); |
1da177e4 LT |
38 | |
39 | /* Let go of any associated proc directory entry */ | |
40 | de = PROC_I(inode)->pde; | |
99b76233 | 41 | if (de) |
135d5655 | 42 | pde_put(de); |
dfef6dcd AV |
43 | head = PROC_I(inode)->sysctl; |
44 | if (head) { | |
45 | rcu_assign_pointer(PROC_I(inode)->sysctl, NULL); | |
46 | sysctl_head_put(head); | |
47 | } | |
6b4e306a EB |
48 | /* Release any associated namespace */ |
49 | ns_ops = PROC_I(inode)->ns_ops; | |
50 | if (ns_ops && ns_ops->put) | |
51 | ns_ops->put(PROC_I(inode)->ns); | |
1da177e4 LT |
52 | } |
53 | ||
e18b890b | 54 | static struct kmem_cache * proc_inode_cachep; |
1da177e4 LT |
55 | |
56 | static struct inode *proc_alloc_inode(struct super_block *sb) | |
57 | { | |
58 | struct proc_inode *ei; | |
59 | struct inode *inode; | |
60 | ||
e94b1766 | 61 | ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
62 | if (!ei) |
63 | return NULL; | |
13b41b09 | 64 | ei->pid = NULL; |
aed7a6c4 | 65 | ei->fd = 0; |
1da177e4 LT |
66 | ei->op.proc_get_link = NULL; |
67 | ei->pde = NULL; | |
9043476f AV |
68 | ei->sysctl = NULL; |
69 | ei->sysctl_entry = NULL; | |
6b4e306a EB |
70 | ei->ns = NULL; |
71 | ei->ns_ops = NULL; | |
1da177e4 LT |
72 | inode = &ei->vfs_inode; |
73 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
74 | return inode; | |
75 | } | |
76 | ||
fa0d7e3d | 77 | static void proc_i_callback(struct rcu_head *head) |
1da177e4 | 78 | { |
fa0d7e3d NP |
79 | struct inode *inode = container_of(head, struct inode, i_rcu); |
80 | INIT_LIST_HEAD(&inode->i_dentry); | |
1da177e4 LT |
81 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); |
82 | } | |
83 | ||
fa0d7e3d NP |
84 | static void proc_destroy_inode(struct inode *inode) |
85 | { | |
86 | call_rcu(&inode->i_rcu, proc_i_callback); | |
87 | } | |
88 | ||
51cc5068 | 89 | static void init_once(void *foo) |
1da177e4 LT |
90 | { |
91 | struct proc_inode *ei = (struct proc_inode *) foo; | |
92 | ||
a35afb83 | 93 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 94 | } |
20c2df83 | 95 | |
5bcd7ff9 | 96 | void __init proc_init_inodecache(void) |
1da177e4 LT |
97 | { |
98 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
99 | sizeof(struct proc_inode), | |
fffb60f9 | 100 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 101 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 102 | init_once); |
1da177e4 LT |
103 | } |
104 | ||
ee9b6d61 | 105 | static const struct super_operations proc_sops = { |
1da177e4 LT |
106 | .alloc_inode = proc_alloc_inode, |
107 | .destroy_inode = proc_destroy_inode, | |
1da177e4 | 108 | .drop_inode = generic_delete_inode, |
8267952b | 109 | .evict_inode = proc_evict_inode, |
1da177e4 | 110 | .statfs = simple_statfs, |
1da177e4 LT |
111 | }; |
112 | ||
881adb85 | 113 | static void __pde_users_dec(struct proc_dir_entry *pde) |
786d7e16 | 114 | { |
786d7e16 AD |
115 | pde->pde_users--; |
116 | if (pde->pde_unload_completion && pde->pde_users == 0) | |
117 | complete(pde->pde_unload_completion); | |
881adb85 AD |
118 | } |
119 | ||
3dec7f59 | 120 | void pde_users_dec(struct proc_dir_entry *pde) |
881adb85 AD |
121 | { |
122 | spin_lock(&pde->pde_unload_lock); | |
123 | __pde_users_dec(pde); | |
786d7e16 AD |
124 | spin_unlock(&pde->pde_unload_lock); |
125 | } | |
126 | ||
127 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) | |
128 | { | |
129 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
130 | loff_t rv = -EINVAL; | |
131 | loff_t (*llseek)(struct file *, loff_t, int); | |
132 | ||
133 | spin_lock(&pde->pde_unload_lock); | |
134 | /* | |
135 | * remove_proc_entry() is going to delete PDE (as part of module | |
136 | * cleanup sequence). No new callers into module allowed. | |
137 | */ | |
138 | if (!pde->proc_fops) { | |
139 | spin_unlock(&pde->pde_unload_lock); | |
140 | return rv; | |
141 | } | |
142 | /* | |
143 | * Bump refcount so that remove_proc_entry will wail for ->llseek to | |
144 | * complete. | |
145 | */ | |
146 | pde->pde_users++; | |
147 | /* | |
148 | * Save function pointer under lock, to protect against ->proc_fops | |
149 | * NULL'ifying right after ->pde_unload_lock is dropped. | |
150 | */ | |
151 | llseek = pde->proc_fops->llseek; | |
152 | spin_unlock(&pde->pde_unload_lock); | |
153 | ||
154 | if (!llseek) | |
155 | llseek = default_llseek; | |
156 | rv = llseek(file, offset, whence); | |
157 | ||
158 | pde_users_dec(pde); | |
159 | return rv; | |
160 | } | |
161 | ||
162 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
163 | { | |
164 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
165 | ssize_t rv = -EIO; | |
166 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); | |
167 | ||
168 | spin_lock(&pde->pde_unload_lock); | |
169 | if (!pde->proc_fops) { | |
170 | spin_unlock(&pde->pde_unload_lock); | |
171 | return rv; | |
172 | } | |
173 | pde->pde_users++; | |
174 | read = pde->proc_fops->read; | |
175 | spin_unlock(&pde->pde_unload_lock); | |
176 | ||
177 | if (read) | |
178 | rv = read(file, buf, count, ppos); | |
179 | ||
180 | pde_users_dec(pde); | |
181 | return rv; | |
182 | } | |
183 | ||
184 | static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
185 | { | |
186 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
187 | ssize_t rv = -EIO; | |
188 | ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); | |
189 | ||
190 | spin_lock(&pde->pde_unload_lock); | |
191 | if (!pde->proc_fops) { | |
192 | spin_unlock(&pde->pde_unload_lock); | |
193 | return rv; | |
194 | } | |
195 | pde->pde_users++; | |
196 | write = pde->proc_fops->write; | |
197 | spin_unlock(&pde->pde_unload_lock); | |
198 | ||
199 | if (write) | |
200 | rv = write(file, buf, count, ppos); | |
201 | ||
202 | pde_users_dec(pde); | |
203 | return rv; | |
204 | } | |
205 | ||
206 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
207 | { | |
208 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
dd23aae4 | 209 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 AD |
210 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
211 | ||
212 | spin_lock(&pde->pde_unload_lock); | |
213 | if (!pde->proc_fops) { | |
214 | spin_unlock(&pde->pde_unload_lock); | |
215 | return rv; | |
216 | } | |
217 | pde->pde_users++; | |
218 | poll = pde->proc_fops->poll; | |
219 | spin_unlock(&pde->pde_unload_lock); | |
220 | ||
221 | if (poll) | |
222 | rv = poll(file, pts); | |
223 | ||
224 | pde_users_dec(pde); | |
225 | return rv; | |
226 | } | |
227 | ||
228 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
229 | { | |
230 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
231 | long rv = -ENOTTY; | |
b19dd42f | 232 | long (*ioctl)(struct file *, unsigned int, unsigned long); |
786d7e16 AD |
233 | |
234 | spin_lock(&pde->pde_unload_lock); | |
235 | if (!pde->proc_fops) { | |
236 | spin_unlock(&pde->pde_unload_lock); | |
237 | return rv; | |
238 | } | |
239 | pde->pde_users++; | |
b19dd42f | 240 | ioctl = pde->proc_fops->unlocked_ioctl; |
786d7e16 AD |
241 | spin_unlock(&pde->pde_unload_lock); |
242 | ||
b19dd42f AB |
243 | if (ioctl) |
244 | rv = ioctl(file, cmd, arg); | |
786d7e16 AD |
245 | |
246 | pde_users_dec(pde); | |
247 | return rv; | |
248 | } | |
249 | ||
250 | #ifdef CONFIG_COMPAT | |
251 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
252 | { | |
253 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
254 | long rv = -ENOTTY; | |
255 | long (*compat_ioctl)(struct file *, unsigned int, unsigned long); | |
256 | ||
257 | spin_lock(&pde->pde_unload_lock); | |
258 | if (!pde->proc_fops) { | |
259 | spin_unlock(&pde->pde_unload_lock); | |
260 | return rv; | |
261 | } | |
262 | pde->pde_users++; | |
263 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
264 | spin_unlock(&pde->pde_unload_lock); | |
265 | ||
266 | if (compat_ioctl) | |
267 | rv = compat_ioctl(file, cmd, arg); | |
268 | ||
269 | pde_users_dec(pde); | |
270 | return rv; | |
271 | } | |
272 | #endif | |
273 | ||
274 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
275 | { | |
276 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
277 | int rv = -EIO; | |
278 | int (*mmap)(struct file *, struct vm_area_struct *); | |
279 | ||
280 | spin_lock(&pde->pde_unload_lock); | |
281 | if (!pde->proc_fops) { | |
282 | spin_unlock(&pde->pde_unload_lock); | |
283 | return rv; | |
284 | } | |
285 | pde->pde_users++; | |
286 | mmap = pde->proc_fops->mmap; | |
287 | spin_unlock(&pde->pde_unload_lock); | |
288 | ||
289 | if (mmap) | |
290 | rv = mmap(file, vma); | |
291 | ||
292 | pde_users_dec(pde); | |
293 | return rv; | |
294 | } | |
295 | ||
296 | static int proc_reg_open(struct inode *inode, struct file *file) | |
297 | { | |
298 | struct proc_dir_entry *pde = PDE(inode); | |
299 | int rv = 0; | |
300 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
301 | int (*release)(struct inode *, struct file *); |
302 | struct pde_opener *pdeo; | |
303 | ||
304 | /* | |
305 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
306 | * sequence. ->release won't be called because ->proc_fops will be | |
307 | * cleared. Depending on complexity of ->release, consequences vary. | |
308 | * | |
309 | * We can't wait for mercy when close will be done for real, it's | |
310 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
311 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
312 | * for later. | |
313 | */ | |
314 | pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); | |
315 | if (!pdeo) | |
316 | return -ENOMEM; | |
786d7e16 AD |
317 | |
318 | spin_lock(&pde->pde_unload_lock); | |
319 | if (!pde->proc_fops) { | |
320 | spin_unlock(&pde->pde_unload_lock); | |
881adb85 | 321 | kfree(pdeo); |
d2857e79 | 322 | return -ENOENT; |
786d7e16 AD |
323 | } |
324 | pde->pde_users++; | |
325 | open = pde->proc_fops->open; | |
881adb85 | 326 | release = pde->proc_fops->release; |
786d7e16 AD |
327 | spin_unlock(&pde->pde_unload_lock); |
328 | ||
329 | if (open) | |
330 | rv = open(inode, file); | |
331 | ||
881adb85 AD |
332 | spin_lock(&pde->pde_unload_lock); |
333 | if (rv == 0 && release) { | |
334 | /* To know what to release. */ | |
335 | pdeo->inode = inode; | |
336 | pdeo->file = file; | |
337 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
338 | pdeo->release = release; | |
339 | list_add(&pdeo->lh, &pde->pde_openers); | |
340 | } else | |
341 | kfree(pdeo); | |
342 | __pde_users_dec(pde); | |
343 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
344 | return rv; |
345 | } | |
346 | ||
881adb85 AD |
347 | static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
348 | struct inode *inode, struct file *file) | |
349 | { | |
350 | struct pde_opener *pdeo; | |
351 | ||
352 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { | |
353 | if (pdeo->inode == inode && pdeo->file == file) | |
354 | return pdeo; | |
355 | } | |
356 | return NULL; | |
357 | } | |
358 | ||
786d7e16 AD |
359 | static int proc_reg_release(struct inode *inode, struct file *file) |
360 | { | |
361 | struct proc_dir_entry *pde = PDE(inode); | |
362 | int rv = 0; | |
363 | int (*release)(struct inode *, struct file *); | |
881adb85 | 364 | struct pde_opener *pdeo; |
786d7e16 AD |
365 | |
366 | spin_lock(&pde->pde_unload_lock); | |
881adb85 | 367 | pdeo = find_pde_opener(pde, inode, file); |
786d7e16 | 368 | if (!pde->proc_fops) { |
881adb85 AD |
369 | /* |
370 | * Can't simply exit, __fput() will think that everything is OK, | |
371 | * and move on to freeing struct file. remove_proc_entry() will | |
372 | * find slacker in opener's list and will try to do non-trivial | |
373 | * things with struct file. Therefore, remove opener from list. | |
374 | * | |
375 | * But if opener is removed from list, who will ->release it? | |
376 | */ | |
377 | if (pdeo) { | |
378 | list_del(&pdeo->lh); | |
379 | spin_unlock(&pde->pde_unload_lock); | |
380 | rv = pdeo->release(inode, file); | |
381 | kfree(pdeo); | |
382 | } else | |
383 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
384 | return rv; |
385 | } | |
386 | pde->pde_users++; | |
387 | release = pde->proc_fops->release; | |
881adb85 AD |
388 | if (pdeo) { |
389 | list_del(&pdeo->lh); | |
390 | kfree(pdeo); | |
391 | } | |
786d7e16 AD |
392 | spin_unlock(&pde->pde_unload_lock); |
393 | ||
394 | if (release) | |
395 | rv = release(inode, file); | |
396 | ||
397 | pde_users_dec(pde); | |
398 | return rv; | |
399 | } | |
400 | ||
401 | static const struct file_operations proc_reg_file_ops = { | |
402 | .llseek = proc_reg_llseek, | |
403 | .read = proc_reg_read, | |
404 | .write = proc_reg_write, | |
405 | .poll = proc_reg_poll, | |
406 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
407 | #ifdef CONFIG_COMPAT | |
408 | .compat_ioctl = proc_reg_compat_ioctl, | |
409 | #endif | |
410 | .mmap = proc_reg_mmap, | |
411 | .open = proc_reg_open, | |
412 | .release = proc_reg_release, | |
413 | }; | |
414 | ||
778f3dd5 DM |
415 | #ifdef CONFIG_COMPAT |
416 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
417 | .llseek = proc_reg_llseek, | |
418 | .read = proc_reg_read, | |
419 | .write = proc_reg_write, | |
420 | .poll = proc_reg_poll, | |
421 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
422 | .mmap = proc_reg_mmap, | |
423 | .open = proc_reg_open, | |
424 | .release = proc_reg_release, | |
425 | }; | |
426 | #endif | |
427 | ||
6d1b6e4e | 428 | struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) |
1da177e4 LT |
429 | { |
430 | struct inode * inode; | |
431 | ||
6d1b6e4e | 432 | inode = iget_locked(sb, de->low_ino); |
1da177e4 | 433 | if (!inode) |
99b76233 | 434 | return NULL; |
a1d4aebb DH |
435 | if (inode->i_state & I_NEW) { |
436 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
437 | PROC_I(inode)->fd = 0; | |
438 | PROC_I(inode)->pde = de; | |
5e971dce AD |
439 | |
440 | if (de->mode) { | |
441 | inode->i_mode = de->mode; | |
442 | inode->i_uid = de->uid; | |
443 | inode->i_gid = de->gid; | |
444 | } | |
445 | if (de->size) | |
446 | inode->i_size = de->size; | |
447 | if (de->nlink) | |
448 | inode->i_nlink = de->nlink; | |
449 | if (de->proc_iops) | |
450 | inode->i_op = de->proc_iops; | |
451 | if (de->proc_fops) { | |
452 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 453 | #ifdef CONFIG_COMPAT |
5e971dce AD |
454 | if (!de->proc_fops->compat_ioctl) |
455 | inode->i_fop = | |
456 | &proc_reg_file_ops_no_compat; | |
457 | else | |
778f3dd5 | 458 | #endif |
5e971dce AD |
459 | inode->i_fop = &proc_reg_file_ops; |
460 | } else { | |
461 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 462 | } |
786d7e16 | 463 | } |
a1d4aebb | 464 | unlock_new_inode(inode); |
99b76233 | 465 | } else |
135d5655 | 466 | pde_put(de); |
1da177e4 | 467 | return inode; |
1da177e4 LT |
468 | } |
469 | ||
07543f5c | 470 | int proc_fill_super(struct super_block *s) |
1da177e4 LT |
471 | { |
472 | struct inode * root_inode; | |
473 | ||
92d03285 | 474 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
475 | s->s_blocksize = 1024; |
476 | s->s_blocksize_bits = 10; | |
477 | s->s_magic = PROC_SUPER_MAGIC; | |
478 | s->s_op = &proc_sops; | |
479 | s->s_time_gran = 1; | |
480 | ||
135d5655 | 481 | pde_get(&proc_root); |
6d1b6e4e | 482 | root_inode = proc_get_inode(s, &proc_root); |
1da177e4 LT |
483 | if (!root_inode) |
484 | goto out_no_root; | |
1da177e4 LT |
485 | root_inode->i_uid = 0; |
486 | root_inode->i_gid = 0; | |
487 | s->s_root = d_alloc_root(root_inode); | |
488 | if (!s->s_root) | |
489 | goto out_no_root; | |
490 | return 0; | |
491 | ||
492 | out_no_root: | |
493 | printk("proc_read_super: get root inode failed\n"); | |
494 | iput(root_inode); | |
135d5655 | 495 | pde_put(&proc_root); |
1da177e4 LT |
496 | return -ENOMEM; |
497 | } |