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 | 79 | struct inode *inode = container_of(head, struct inode, i_rcu); |
1da177e4 LT |
80 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); |
81 | } | |
82 | ||
fa0d7e3d NP |
83 | static void proc_destroy_inode(struct inode *inode) |
84 | { | |
85 | call_rcu(&inode->i_rcu, proc_i_callback); | |
86 | } | |
87 | ||
51cc5068 | 88 | static void init_once(void *foo) |
1da177e4 LT |
89 | { |
90 | struct proc_inode *ei = (struct proc_inode *) foo; | |
91 | ||
a35afb83 | 92 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 93 | } |
20c2df83 | 94 | |
5bcd7ff9 | 95 | void __init proc_init_inodecache(void) |
1da177e4 LT |
96 | { |
97 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
98 | sizeof(struct proc_inode), | |
fffb60f9 | 99 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 100 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 101 | init_once); |
1da177e4 LT |
102 | } |
103 | ||
ee9b6d61 | 104 | static const struct super_operations proc_sops = { |
1da177e4 LT |
105 | .alloc_inode = proc_alloc_inode, |
106 | .destroy_inode = proc_destroy_inode, | |
1da177e4 | 107 | .drop_inode = generic_delete_inode, |
8267952b | 108 | .evict_inode = proc_evict_inode, |
1da177e4 | 109 | .statfs = simple_statfs, |
1da177e4 LT |
110 | }; |
111 | ||
881adb85 | 112 | static void __pde_users_dec(struct proc_dir_entry *pde) |
786d7e16 | 113 | { |
786d7e16 AD |
114 | pde->pde_users--; |
115 | if (pde->pde_unload_completion && pde->pde_users == 0) | |
116 | complete(pde->pde_unload_completion); | |
881adb85 AD |
117 | } |
118 | ||
3dec7f59 | 119 | void pde_users_dec(struct proc_dir_entry *pde) |
881adb85 AD |
120 | { |
121 | spin_lock(&pde->pde_unload_lock); | |
122 | __pde_users_dec(pde); | |
786d7e16 AD |
123 | spin_unlock(&pde->pde_unload_lock); |
124 | } | |
125 | ||
126 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) | |
127 | { | |
128 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
129 | loff_t rv = -EINVAL; | |
130 | loff_t (*llseek)(struct file *, loff_t, int); | |
131 | ||
132 | spin_lock(&pde->pde_unload_lock); | |
133 | /* | |
134 | * remove_proc_entry() is going to delete PDE (as part of module | |
135 | * cleanup sequence). No new callers into module allowed. | |
136 | */ | |
137 | if (!pde->proc_fops) { | |
138 | spin_unlock(&pde->pde_unload_lock); | |
139 | return rv; | |
140 | } | |
141 | /* | |
142 | * Bump refcount so that remove_proc_entry will wail for ->llseek to | |
143 | * complete. | |
144 | */ | |
145 | pde->pde_users++; | |
146 | /* | |
147 | * Save function pointer under lock, to protect against ->proc_fops | |
148 | * NULL'ifying right after ->pde_unload_lock is dropped. | |
149 | */ | |
150 | llseek = pde->proc_fops->llseek; | |
151 | spin_unlock(&pde->pde_unload_lock); | |
152 | ||
153 | if (!llseek) | |
154 | llseek = default_llseek; | |
155 | rv = llseek(file, offset, whence); | |
156 | ||
157 | pde_users_dec(pde); | |
158 | return rv; | |
159 | } | |
160 | ||
161 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
162 | { | |
163 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
164 | ssize_t rv = -EIO; | |
165 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); | |
166 | ||
167 | spin_lock(&pde->pde_unload_lock); | |
168 | if (!pde->proc_fops) { | |
169 | spin_unlock(&pde->pde_unload_lock); | |
170 | return rv; | |
171 | } | |
172 | pde->pde_users++; | |
173 | read = pde->proc_fops->read; | |
174 | spin_unlock(&pde->pde_unload_lock); | |
175 | ||
176 | if (read) | |
177 | rv = read(file, buf, count, ppos); | |
178 | ||
179 | pde_users_dec(pde); | |
180 | return rv; | |
181 | } | |
182 | ||
183 | static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
184 | { | |
185 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
186 | ssize_t rv = -EIO; | |
187 | ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); | |
188 | ||
189 | spin_lock(&pde->pde_unload_lock); | |
190 | if (!pde->proc_fops) { | |
191 | spin_unlock(&pde->pde_unload_lock); | |
192 | return rv; | |
193 | } | |
194 | pde->pde_users++; | |
195 | write = pde->proc_fops->write; | |
196 | spin_unlock(&pde->pde_unload_lock); | |
197 | ||
198 | if (write) | |
199 | rv = write(file, buf, count, ppos); | |
200 | ||
201 | pde_users_dec(pde); | |
202 | return rv; | |
203 | } | |
204 | ||
205 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
206 | { | |
207 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
dd23aae4 | 208 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 AD |
209 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
210 | ||
211 | spin_lock(&pde->pde_unload_lock); | |
212 | if (!pde->proc_fops) { | |
213 | spin_unlock(&pde->pde_unload_lock); | |
214 | return rv; | |
215 | } | |
216 | pde->pde_users++; | |
217 | poll = pde->proc_fops->poll; | |
218 | spin_unlock(&pde->pde_unload_lock); | |
219 | ||
220 | if (poll) | |
221 | rv = poll(file, pts); | |
222 | ||
223 | pde_users_dec(pde); | |
224 | return rv; | |
225 | } | |
226 | ||
227 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
228 | { | |
229 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
230 | long rv = -ENOTTY; | |
b19dd42f | 231 | long (*ioctl)(struct file *, unsigned int, unsigned long); |
786d7e16 AD |
232 | |
233 | spin_lock(&pde->pde_unload_lock); | |
234 | if (!pde->proc_fops) { | |
235 | spin_unlock(&pde->pde_unload_lock); | |
236 | return rv; | |
237 | } | |
238 | pde->pde_users++; | |
b19dd42f | 239 | ioctl = pde->proc_fops->unlocked_ioctl; |
786d7e16 AD |
240 | spin_unlock(&pde->pde_unload_lock); |
241 | ||
b19dd42f AB |
242 | if (ioctl) |
243 | rv = ioctl(file, cmd, arg); | |
786d7e16 AD |
244 | |
245 | pde_users_dec(pde); | |
246 | return rv; | |
247 | } | |
248 | ||
249 | #ifdef CONFIG_COMPAT | |
250 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
251 | { | |
252 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
253 | long rv = -ENOTTY; | |
254 | long (*compat_ioctl)(struct file *, unsigned int, unsigned long); | |
255 | ||
256 | spin_lock(&pde->pde_unload_lock); | |
257 | if (!pde->proc_fops) { | |
258 | spin_unlock(&pde->pde_unload_lock); | |
259 | return rv; | |
260 | } | |
261 | pde->pde_users++; | |
262 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
263 | spin_unlock(&pde->pde_unload_lock); | |
264 | ||
265 | if (compat_ioctl) | |
266 | rv = compat_ioctl(file, cmd, arg); | |
267 | ||
268 | pde_users_dec(pde); | |
269 | return rv; | |
270 | } | |
271 | #endif | |
272 | ||
273 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
274 | { | |
275 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
276 | int rv = -EIO; | |
277 | int (*mmap)(struct file *, struct vm_area_struct *); | |
278 | ||
279 | spin_lock(&pde->pde_unload_lock); | |
280 | if (!pde->proc_fops) { | |
281 | spin_unlock(&pde->pde_unload_lock); | |
282 | return rv; | |
283 | } | |
284 | pde->pde_users++; | |
285 | mmap = pde->proc_fops->mmap; | |
286 | spin_unlock(&pde->pde_unload_lock); | |
287 | ||
288 | if (mmap) | |
289 | rv = mmap(file, vma); | |
290 | ||
291 | pde_users_dec(pde); | |
292 | return rv; | |
293 | } | |
294 | ||
295 | static int proc_reg_open(struct inode *inode, struct file *file) | |
296 | { | |
297 | struct proc_dir_entry *pde = PDE(inode); | |
298 | int rv = 0; | |
299 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
300 | int (*release)(struct inode *, struct file *); |
301 | struct pde_opener *pdeo; | |
302 | ||
303 | /* | |
304 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
305 | * sequence. ->release won't be called because ->proc_fops will be | |
306 | * cleared. Depending on complexity of ->release, consequences vary. | |
307 | * | |
308 | * We can't wait for mercy when close will be done for real, it's | |
309 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
310 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
311 | * for later. | |
312 | */ | |
313 | pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); | |
314 | if (!pdeo) | |
315 | return -ENOMEM; | |
786d7e16 AD |
316 | |
317 | spin_lock(&pde->pde_unload_lock); | |
318 | if (!pde->proc_fops) { | |
319 | spin_unlock(&pde->pde_unload_lock); | |
881adb85 | 320 | kfree(pdeo); |
d2857e79 | 321 | return -ENOENT; |
786d7e16 AD |
322 | } |
323 | pde->pde_users++; | |
324 | open = pde->proc_fops->open; | |
881adb85 | 325 | release = pde->proc_fops->release; |
786d7e16 AD |
326 | spin_unlock(&pde->pde_unload_lock); |
327 | ||
328 | if (open) | |
329 | rv = open(inode, file); | |
330 | ||
881adb85 AD |
331 | spin_lock(&pde->pde_unload_lock); |
332 | if (rv == 0 && release) { | |
333 | /* To know what to release. */ | |
334 | pdeo->inode = inode; | |
335 | pdeo->file = file; | |
336 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
337 | pdeo->release = release; | |
338 | list_add(&pdeo->lh, &pde->pde_openers); | |
339 | } else | |
340 | kfree(pdeo); | |
341 | __pde_users_dec(pde); | |
342 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
343 | return rv; |
344 | } | |
345 | ||
881adb85 AD |
346 | static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
347 | struct inode *inode, struct file *file) | |
348 | { | |
349 | struct pde_opener *pdeo; | |
350 | ||
351 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { | |
352 | if (pdeo->inode == inode && pdeo->file == file) | |
353 | return pdeo; | |
354 | } | |
355 | return NULL; | |
356 | } | |
357 | ||
786d7e16 AD |
358 | static int proc_reg_release(struct inode *inode, struct file *file) |
359 | { | |
360 | struct proc_dir_entry *pde = PDE(inode); | |
361 | int rv = 0; | |
362 | int (*release)(struct inode *, struct file *); | |
881adb85 | 363 | struct pde_opener *pdeo; |
786d7e16 AD |
364 | |
365 | spin_lock(&pde->pde_unload_lock); | |
881adb85 | 366 | pdeo = find_pde_opener(pde, inode, file); |
786d7e16 | 367 | if (!pde->proc_fops) { |
881adb85 AD |
368 | /* |
369 | * Can't simply exit, __fput() will think that everything is OK, | |
370 | * and move on to freeing struct file. remove_proc_entry() will | |
371 | * find slacker in opener's list and will try to do non-trivial | |
372 | * things with struct file. Therefore, remove opener from list. | |
373 | * | |
374 | * But if opener is removed from list, who will ->release it? | |
375 | */ | |
376 | if (pdeo) { | |
377 | list_del(&pdeo->lh); | |
378 | spin_unlock(&pde->pde_unload_lock); | |
379 | rv = pdeo->release(inode, file); | |
380 | kfree(pdeo); | |
381 | } else | |
382 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
383 | return rv; |
384 | } | |
385 | pde->pde_users++; | |
386 | release = pde->proc_fops->release; | |
881adb85 AD |
387 | if (pdeo) { |
388 | list_del(&pdeo->lh); | |
389 | kfree(pdeo); | |
390 | } | |
786d7e16 AD |
391 | spin_unlock(&pde->pde_unload_lock); |
392 | ||
393 | if (release) | |
394 | rv = release(inode, file); | |
395 | ||
396 | pde_users_dec(pde); | |
397 | return rv; | |
398 | } | |
399 | ||
400 | static const struct file_operations proc_reg_file_ops = { | |
401 | .llseek = proc_reg_llseek, | |
402 | .read = proc_reg_read, | |
403 | .write = proc_reg_write, | |
404 | .poll = proc_reg_poll, | |
405 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
406 | #ifdef CONFIG_COMPAT | |
407 | .compat_ioctl = proc_reg_compat_ioctl, | |
408 | #endif | |
409 | .mmap = proc_reg_mmap, | |
410 | .open = proc_reg_open, | |
411 | .release = proc_reg_release, | |
412 | }; | |
413 | ||
778f3dd5 DM |
414 | #ifdef CONFIG_COMPAT |
415 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
416 | .llseek = proc_reg_llseek, | |
417 | .read = proc_reg_read, | |
418 | .write = proc_reg_write, | |
419 | .poll = proc_reg_poll, | |
420 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
421 | .mmap = proc_reg_mmap, | |
422 | .open = proc_reg_open, | |
423 | .release = proc_reg_release, | |
424 | }; | |
425 | #endif | |
426 | ||
6d1b6e4e | 427 | struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) |
1da177e4 LT |
428 | { |
429 | struct inode * inode; | |
430 | ||
6d1b6e4e | 431 | inode = iget_locked(sb, de->low_ino); |
1da177e4 | 432 | if (!inode) |
99b76233 | 433 | return NULL; |
a1d4aebb DH |
434 | if (inode->i_state & I_NEW) { |
435 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
436 | PROC_I(inode)->fd = 0; | |
437 | PROC_I(inode)->pde = de; | |
5e971dce AD |
438 | |
439 | if (de->mode) { | |
440 | inode->i_mode = de->mode; | |
441 | inode->i_uid = de->uid; | |
442 | inode->i_gid = de->gid; | |
443 | } | |
444 | if (de->size) | |
445 | inode->i_size = de->size; | |
446 | if (de->nlink) | |
bfe86848 | 447 | set_nlink(inode, de->nlink); |
5e971dce AD |
448 | if (de->proc_iops) |
449 | inode->i_op = de->proc_iops; | |
450 | if (de->proc_fops) { | |
451 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 452 | #ifdef CONFIG_COMPAT |
5e971dce AD |
453 | if (!de->proc_fops->compat_ioctl) |
454 | inode->i_fop = | |
455 | &proc_reg_file_ops_no_compat; | |
456 | else | |
778f3dd5 | 457 | #endif |
5e971dce AD |
458 | inode->i_fop = &proc_reg_file_ops; |
459 | } else { | |
460 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 461 | } |
786d7e16 | 462 | } |
a1d4aebb | 463 | unlock_new_inode(inode); |
99b76233 | 464 | } else |
135d5655 | 465 | pde_put(de); |
1da177e4 | 466 | return inode; |
1da177e4 LT |
467 | } |
468 | ||
07543f5c | 469 | int proc_fill_super(struct super_block *s) |
1da177e4 LT |
470 | { |
471 | struct inode * root_inode; | |
472 | ||
92d03285 | 473 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
474 | s->s_blocksize = 1024; |
475 | s->s_blocksize_bits = 10; | |
476 | s->s_magic = PROC_SUPER_MAGIC; | |
477 | s->s_op = &proc_sops; | |
478 | s->s_time_gran = 1; | |
479 | ||
135d5655 | 480 | pde_get(&proc_root); |
6d1b6e4e | 481 | root_inode = proc_get_inode(s, &proc_root); |
1da177e4 LT |
482 | if (!root_inode) |
483 | goto out_no_root; | |
1da177e4 LT |
484 | root_inode->i_uid = 0; |
485 | root_inode->i_gid = 0; | |
486 | s->s_root = d_alloc_root(root_inode); | |
487 | if (!s->s_root) | |
488 | goto out_no_root; | |
489 | return 0; | |
490 | ||
491 | out_no_root: | |
492 | printk("proc_read_super: get root inode failed\n"); | |
493 | iput(root_inode); | |
135d5655 | 494 | pde_put(&proc_root); |
1da177e4 LT |
495 | return -ENOMEM; |
496 | } |