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Commit | Line | Data |
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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> |
5a0e3ad6 | 21 | #include <linux/slab.h> |
1da177e4 LT |
22 | |
23 | #include <asm/system.h> | |
24 | #include <asm/uaccess.h> | |
25 | ||
fee781e6 | 26 | #include "internal.h" |
1da177e4 | 27 | |
8267952b | 28 | static void proc_evict_inode(struct inode *inode) |
1da177e4 LT |
29 | { |
30 | struct proc_dir_entry *de; | |
1da177e4 | 31 | |
fef26658 | 32 | truncate_inode_pages(&inode->i_data, 0); |
8267952b | 33 | end_writeback(inode); |
fef26658 | 34 | |
99f89551 | 35 | /* Stop tracking associated processes */ |
13b41b09 | 36 | put_pid(PROC_I(inode)->pid); |
1da177e4 LT |
37 | |
38 | /* Let go of any associated proc directory entry */ | |
39 | de = PROC_I(inode)->pde; | |
99b76233 | 40 | if (de) |
135d5655 | 41 | pde_put(de); |
9043476f AV |
42 | if (PROC_I(inode)->sysctl) |
43 | sysctl_head_put(PROC_I(inode)->sysctl); | |
1da177e4 LT |
44 | } |
45 | ||
46 | struct vfsmount *proc_mnt; | |
47 | ||
e18b890b | 48 | static struct kmem_cache * proc_inode_cachep; |
1da177e4 LT |
49 | |
50 | static struct inode *proc_alloc_inode(struct super_block *sb) | |
51 | { | |
52 | struct proc_inode *ei; | |
53 | struct inode *inode; | |
54 | ||
e94b1766 | 55 | ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
56 | if (!ei) |
57 | return NULL; | |
13b41b09 | 58 | ei->pid = NULL; |
aed7a6c4 | 59 | ei->fd = 0; |
1da177e4 LT |
60 | ei->op.proc_get_link = NULL; |
61 | ei->pde = NULL; | |
9043476f AV |
62 | ei->sysctl = NULL; |
63 | ei->sysctl_entry = NULL; | |
1da177e4 LT |
64 | inode = &ei->vfs_inode; |
65 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
66 | return inode; | |
67 | } | |
68 | ||
69 | static void proc_destroy_inode(struct inode *inode) | |
70 | { | |
71 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); | |
72 | } | |
73 | ||
51cc5068 | 74 | static void init_once(void *foo) |
1da177e4 LT |
75 | { |
76 | struct proc_inode *ei = (struct proc_inode *) foo; | |
77 | ||
a35afb83 | 78 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 79 | } |
20c2df83 | 80 | |
5bcd7ff9 | 81 | void __init proc_init_inodecache(void) |
1da177e4 LT |
82 | { |
83 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
84 | sizeof(struct proc_inode), | |
fffb60f9 | 85 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 86 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 87 | init_once); |
1da177e4 LT |
88 | } |
89 | ||
ee9b6d61 | 90 | static const struct super_operations proc_sops = { |
1da177e4 LT |
91 | .alloc_inode = proc_alloc_inode, |
92 | .destroy_inode = proc_destroy_inode, | |
1da177e4 | 93 | .drop_inode = generic_delete_inode, |
8267952b | 94 | .evict_inode = proc_evict_inode, |
1da177e4 | 95 | .statfs = simple_statfs, |
1da177e4 LT |
96 | }; |
97 | ||
881adb85 | 98 | static void __pde_users_dec(struct proc_dir_entry *pde) |
786d7e16 | 99 | { |
786d7e16 AD |
100 | pde->pde_users--; |
101 | if (pde->pde_unload_completion && pde->pde_users == 0) | |
102 | complete(pde->pde_unload_completion); | |
881adb85 AD |
103 | } |
104 | ||
3dec7f59 | 105 | void pde_users_dec(struct proc_dir_entry *pde) |
881adb85 AD |
106 | { |
107 | spin_lock(&pde->pde_unload_lock); | |
108 | __pde_users_dec(pde); | |
786d7e16 AD |
109 | spin_unlock(&pde->pde_unload_lock); |
110 | } | |
111 | ||
112 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) | |
113 | { | |
114 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
115 | loff_t rv = -EINVAL; | |
116 | loff_t (*llseek)(struct file *, loff_t, int); | |
117 | ||
118 | spin_lock(&pde->pde_unload_lock); | |
119 | /* | |
120 | * remove_proc_entry() is going to delete PDE (as part of module | |
121 | * cleanup sequence). No new callers into module allowed. | |
122 | */ | |
123 | if (!pde->proc_fops) { | |
124 | spin_unlock(&pde->pde_unload_lock); | |
125 | return rv; | |
126 | } | |
127 | /* | |
128 | * Bump refcount so that remove_proc_entry will wail for ->llseek to | |
129 | * complete. | |
130 | */ | |
131 | pde->pde_users++; | |
132 | /* | |
133 | * Save function pointer under lock, to protect against ->proc_fops | |
134 | * NULL'ifying right after ->pde_unload_lock is dropped. | |
135 | */ | |
136 | llseek = pde->proc_fops->llseek; | |
137 | spin_unlock(&pde->pde_unload_lock); | |
138 | ||
139 | if (!llseek) | |
140 | llseek = default_llseek; | |
141 | rv = llseek(file, offset, whence); | |
142 | ||
143 | pde_users_dec(pde); | |
144 | return rv; | |
145 | } | |
146 | ||
147 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
148 | { | |
149 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
150 | ssize_t rv = -EIO; | |
151 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); | |
152 | ||
153 | spin_lock(&pde->pde_unload_lock); | |
154 | if (!pde->proc_fops) { | |
155 | spin_unlock(&pde->pde_unload_lock); | |
156 | return rv; | |
157 | } | |
158 | pde->pde_users++; | |
159 | read = pde->proc_fops->read; | |
160 | spin_unlock(&pde->pde_unload_lock); | |
161 | ||
162 | if (read) | |
163 | rv = read(file, buf, count, ppos); | |
164 | ||
165 | pde_users_dec(pde); | |
166 | return rv; | |
167 | } | |
168 | ||
169 | static ssize_t proc_reg_write(struct file *file, const 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 (*write)(struct file *, const 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 | write = pde->proc_fops->write; | |
182 | spin_unlock(&pde->pde_unload_lock); | |
183 | ||
184 | if (write) | |
185 | rv = write(file, buf, count, ppos); | |
186 | ||
187 | pde_users_dec(pde); | |
188 | return rv; | |
189 | } | |
190 | ||
191 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
192 | { | |
193 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
dd23aae4 | 194 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 AD |
195 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
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 | poll = pde->proc_fops->poll; | |
204 | spin_unlock(&pde->pde_unload_lock); | |
205 | ||
206 | if (poll) | |
207 | rv = poll(file, pts); | |
208 | ||
209 | pde_users_dec(pde); | |
210 | return rv; | |
211 | } | |
212 | ||
213 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
214 | { | |
215 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
216 | long rv = -ENOTTY; | |
b19dd42f | 217 | long (*ioctl)(struct file *, unsigned int, unsigned long); |
786d7e16 AD |
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++; | |
b19dd42f | 225 | ioctl = pde->proc_fops->unlocked_ioctl; |
786d7e16 AD |
226 | spin_unlock(&pde->pde_unload_lock); |
227 | ||
b19dd42f AB |
228 | if (ioctl) |
229 | rv = ioctl(file, cmd, arg); | |
786d7e16 AD |
230 | |
231 | pde_users_dec(pde); | |
232 | return rv; | |
233 | } | |
234 | ||
235 | #ifdef CONFIG_COMPAT | |
236 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
237 | { | |
238 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
239 | long rv = -ENOTTY; | |
240 | long (*compat_ioctl)(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 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
249 | spin_unlock(&pde->pde_unload_lock); | |
250 | ||
251 | if (compat_ioctl) | |
252 | rv = compat_ioctl(file, cmd, arg); | |
253 | ||
254 | pde_users_dec(pde); | |
255 | return rv; | |
256 | } | |
257 | #endif | |
258 | ||
259 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
260 | { | |
261 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
262 | int rv = -EIO; | |
263 | int (*mmap)(struct file *, struct vm_area_struct *); | |
264 | ||
265 | spin_lock(&pde->pde_unload_lock); | |
266 | if (!pde->proc_fops) { | |
267 | spin_unlock(&pde->pde_unload_lock); | |
268 | return rv; | |
269 | } | |
270 | pde->pde_users++; | |
271 | mmap = pde->proc_fops->mmap; | |
272 | spin_unlock(&pde->pde_unload_lock); | |
273 | ||
274 | if (mmap) | |
275 | rv = mmap(file, vma); | |
276 | ||
277 | pde_users_dec(pde); | |
278 | return rv; | |
279 | } | |
280 | ||
281 | static int proc_reg_open(struct inode *inode, struct file *file) | |
282 | { | |
283 | struct proc_dir_entry *pde = PDE(inode); | |
284 | int rv = 0; | |
285 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
286 | int (*release)(struct inode *, struct file *); |
287 | struct pde_opener *pdeo; | |
288 | ||
289 | /* | |
290 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
291 | * sequence. ->release won't be called because ->proc_fops will be | |
292 | * cleared. Depending on complexity of ->release, consequences vary. | |
293 | * | |
294 | * We can't wait for mercy when close will be done for real, it's | |
295 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
296 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
297 | * for later. | |
298 | */ | |
299 | pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); | |
300 | if (!pdeo) | |
301 | return -ENOMEM; | |
786d7e16 AD |
302 | |
303 | spin_lock(&pde->pde_unload_lock); | |
304 | if (!pde->proc_fops) { | |
305 | spin_unlock(&pde->pde_unload_lock); | |
881adb85 | 306 | kfree(pdeo); |
300b994b | 307 | return -EINVAL; |
786d7e16 AD |
308 | } |
309 | pde->pde_users++; | |
310 | open = pde->proc_fops->open; | |
881adb85 | 311 | release = pde->proc_fops->release; |
786d7e16 AD |
312 | spin_unlock(&pde->pde_unload_lock); |
313 | ||
314 | if (open) | |
315 | rv = open(inode, file); | |
316 | ||
881adb85 AD |
317 | spin_lock(&pde->pde_unload_lock); |
318 | if (rv == 0 && release) { | |
319 | /* To know what to release. */ | |
320 | pdeo->inode = inode; | |
321 | pdeo->file = file; | |
322 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
323 | pdeo->release = release; | |
324 | list_add(&pdeo->lh, &pde->pde_openers); | |
325 | } else | |
326 | kfree(pdeo); | |
327 | __pde_users_dec(pde); | |
328 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
329 | return rv; |
330 | } | |
331 | ||
881adb85 AD |
332 | static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
333 | struct inode *inode, struct file *file) | |
334 | { | |
335 | struct pde_opener *pdeo; | |
336 | ||
337 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { | |
338 | if (pdeo->inode == inode && pdeo->file == file) | |
339 | return pdeo; | |
340 | } | |
341 | return NULL; | |
342 | } | |
343 | ||
786d7e16 AD |
344 | static int proc_reg_release(struct inode *inode, struct file *file) |
345 | { | |
346 | struct proc_dir_entry *pde = PDE(inode); | |
347 | int rv = 0; | |
348 | int (*release)(struct inode *, struct file *); | |
881adb85 | 349 | struct pde_opener *pdeo; |
786d7e16 AD |
350 | |
351 | spin_lock(&pde->pde_unload_lock); | |
881adb85 | 352 | pdeo = find_pde_opener(pde, inode, file); |
786d7e16 | 353 | if (!pde->proc_fops) { |
881adb85 AD |
354 | /* |
355 | * Can't simply exit, __fput() will think that everything is OK, | |
356 | * and move on to freeing struct file. remove_proc_entry() will | |
357 | * find slacker in opener's list and will try to do non-trivial | |
358 | * things with struct file. Therefore, remove opener from list. | |
359 | * | |
360 | * But if opener is removed from list, who will ->release it? | |
361 | */ | |
362 | if (pdeo) { | |
363 | list_del(&pdeo->lh); | |
364 | spin_unlock(&pde->pde_unload_lock); | |
365 | rv = pdeo->release(inode, file); | |
366 | kfree(pdeo); | |
367 | } else | |
368 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
369 | return rv; |
370 | } | |
371 | pde->pde_users++; | |
372 | release = pde->proc_fops->release; | |
881adb85 AD |
373 | if (pdeo) { |
374 | list_del(&pdeo->lh); | |
375 | kfree(pdeo); | |
376 | } | |
786d7e16 AD |
377 | spin_unlock(&pde->pde_unload_lock); |
378 | ||
379 | if (release) | |
380 | rv = release(inode, file); | |
381 | ||
382 | pde_users_dec(pde); | |
383 | return rv; | |
384 | } | |
385 | ||
386 | static const struct file_operations proc_reg_file_ops = { | |
387 | .llseek = proc_reg_llseek, | |
388 | .read = proc_reg_read, | |
389 | .write = proc_reg_write, | |
390 | .poll = proc_reg_poll, | |
391 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
392 | #ifdef CONFIG_COMPAT | |
393 | .compat_ioctl = proc_reg_compat_ioctl, | |
394 | #endif | |
395 | .mmap = proc_reg_mmap, | |
396 | .open = proc_reg_open, | |
397 | .release = proc_reg_release, | |
398 | }; | |
399 | ||
778f3dd5 DM |
400 | #ifdef CONFIG_COMPAT |
401 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
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 | .mmap = proc_reg_mmap, | |
408 | .open = proc_reg_open, | |
409 | .release = proc_reg_release, | |
410 | }; | |
411 | #endif | |
412 | ||
1da177e4 LT |
413 | struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, |
414 | struct proc_dir_entry *de) | |
415 | { | |
416 | struct inode * inode; | |
417 | ||
a1d4aebb | 418 | inode = iget_locked(sb, ino); |
1da177e4 | 419 | if (!inode) |
99b76233 | 420 | return NULL; |
a1d4aebb DH |
421 | if (inode->i_state & I_NEW) { |
422 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
423 | PROC_I(inode)->fd = 0; | |
424 | PROC_I(inode)->pde = de; | |
5e971dce AD |
425 | |
426 | if (de->mode) { | |
427 | inode->i_mode = de->mode; | |
428 | inode->i_uid = de->uid; | |
429 | inode->i_gid = de->gid; | |
430 | } | |
431 | if (de->size) | |
432 | inode->i_size = de->size; | |
433 | if (de->nlink) | |
434 | inode->i_nlink = de->nlink; | |
435 | if (de->proc_iops) | |
436 | inode->i_op = de->proc_iops; | |
437 | if (de->proc_fops) { | |
438 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 439 | #ifdef CONFIG_COMPAT |
5e971dce AD |
440 | if (!de->proc_fops->compat_ioctl) |
441 | inode->i_fop = | |
442 | &proc_reg_file_ops_no_compat; | |
443 | else | |
778f3dd5 | 444 | #endif |
5e971dce AD |
445 | inode->i_fop = &proc_reg_file_ops; |
446 | } else { | |
447 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 448 | } |
786d7e16 | 449 | } |
a1d4aebb | 450 | unlock_new_inode(inode); |
99b76233 | 451 | } else |
135d5655 | 452 | pde_put(de); |
1da177e4 | 453 | return inode; |
1da177e4 LT |
454 | } |
455 | ||
07543f5c | 456 | int proc_fill_super(struct super_block *s) |
1da177e4 LT |
457 | { |
458 | struct inode * root_inode; | |
459 | ||
92d03285 | 460 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
461 | s->s_blocksize = 1024; |
462 | s->s_blocksize_bits = 10; | |
463 | s->s_magic = PROC_SUPER_MAGIC; | |
464 | s->s_op = &proc_sops; | |
465 | s->s_time_gran = 1; | |
466 | ||
135d5655 | 467 | pde_get(&proc_root); |
1da177e4 LT |
468 | root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); |
469 | if (!root_inode) | |
470 | goto out_no_root; | |
1da177e4 LT |
471 | root_inode->i_uid = 0; |
472 | root_inode->i_gid = 0; | |
473 | s->s_root = d_alloc_root(root_inode); | |
474 | if (!s->s_root) | |
475 | goto out_no_root; | |
476 | return 0; | |
477 | ||
478 | out_no_root: | |
479 | printk("proc_read_super: get root inode failed\n"); | |
480 | iput(root_inode); | |
135d5655 | 481 | pde_put(&proc_root); |
1da177e4 LT |
482 | return -ENOMEM; |
483 | } |