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 | |
1da177e4 LT |
27 | static void proc_delete_inode(struct inode *inode) |
28 | { | |
29 | struct proc_dir_entry *de; | |
1da177e4 | 30 | |
fef26658 MF |
31 | truncate_inode_pages(&inode->i_data, 0); |
32 | ||
99f89551 | 33 | /* Stop tracking associated processes */ |
13b41b09 | 34 | put_pid(PROC_I(inode)->pid); |
1da177e4 LT |
35 | |
36 | /* Let go of any associated proc directory entry */ | |
37 | de = PROC_I(inode)->pde; | |
99b76233 | 38 | if (de) |
135d5655 | 39 | pde_put(de); |
9043476f AV |
40 | if (PROC_I(inode)->sysctl) |
41 | sysctl_head_put(PROC_I(inode)->sysctl); | |
1da177e4 LT |
42 | clear_inode(inode); |
43 | } | |
44 | ||
45 | struct vfsmount *proc_mnt; | |
46 | ||
e18b890b | 47 | static struct kmem_cache * proc_inode_cachep; |
1da177e4 LT |
48 | |
49 | static struct inode *proc_alloc_inode(struct super_block *sb) | |
50 | { | |
51 | struct proc_inode *ei; | |
52 | struct inode *inode; | |
53 | ||
e94b1766 | 54 | ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
55 | if (!ei) |
56 | return NULL; | |
13b41b09 | 57 | ei->pid = NULL; |
aed7a6c4 | 58 | ei->fd = 0; |
1da177e4 LT |
59 | ei->op.proc_get_link = NULL; |
60 | ei->pde = NULL; | |
9043476f AV |
61 | ei->sysctl = NULL; |
62 | ei->sysctl_entry = NULL; | |
1da177e4 LT |
63 | inode = &ei->vfs_inode; |
64 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
65 | return inode; | |
66 | } | |
67 | ||
68 | static void proc_destroy_inode(struct inode *inode) | |
69 | { | |
70 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); | |
71 | } | |
72 | ||
51cc5068 | 73 | static void init_once(void *foo) |
1da177e4 LT |
74 | { |
75 | struct proc_inode *ei = (struct proc_inode *) foo; | |
76 | ||
a35afb83 | 77 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 78 | } |
20c2df83 | 79 | |
5bcd7ff9 | 80 | void __init proc_init_inodecache(void) |
1da177e4 LT |
81 | { |
82 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
83 | sizeof(struct proc_inode), | |
fffb60f9 | 84 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 85 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 86 | init_once); |
1da177e4 LT |
87 | } |
88 | ||
ee9b6d61 | 89 | static const struct super_operations proc_sops = { |
1da177e4 LT |
90 | .alloc_inode = proc_alloc_inode, |
91 | .destroy_inode = proc_destroy_inode, | |
1da177e4 LT |
92 | .drop_inode = generic_delete_inode, |
93 | .delete_inode = proc_delete_inode, | |
94 | .statfs = simple_statfs, | |
1da177e4 LT |
95 | }; |
96 | ||
881adb85 | 97 | static void __pde_users_dec(struct proc_dir_entry *pde) |
786d7e16 | 98 | { |
786d7e16 AD |
99 | pde->pde_users--; |
100 | if (pde->pde_unload_completion && pde->pde_users == 0) | |
101 | complete(pde->pde_unload_completion); | |
881adb85 AD |
102 | } |
103 | ||
3dec7f59 | 104 | void pde_users_dec(struct proc_dir_entry *pde) |
881adb85 AD |
105 | { |
106 | spin_lock(&pde->pde_unload_lock); | |
107 | __pde_users_dec(pde); | |
786d7e16 AD |
108 | spin_unlock(&pde->pde_unload_lock); |
109 | } | |
110 | ||
111 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) | |
112 | { | |
113 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
114 | loff_t rv = -EINVAL; | |
115 | loff_t (*llseek)(struct file *, loff_t, int); | |
116 | ||
117 | spin_lock(&pde->pde_unload_lock); | |
118 | /* | |
119 | * remove_proc_entry() is going to delete PDE (as part of module | |
120 | * cleanup sequence). No new callers into module allowed. | |
121 | */ | |
122 | if (!pde->proc_fops) { | |
123 | spin_unlock(&pde->pde_unload_lock); | |
124 | return rv; | |
125 | } | |
126 | /* | |
127 | * Bump refcount so that remove_proc_entry will wail for ->llseek to | |
128 | * complete. | |
129 | */ | |
130 | pde->pde_users++; | |
131 | /* | |
132 | * Save function pointer under lock, to protect against ->proc_fops | |
133 | * NULL'ifying right after ->pde_unload_lock is dropped. | |
134 | */ | |
135 | llseek = pde->proc_fops->llseek; | |
136 | spin_unlock(&pde->pde_unload_lock); | |
137 | ||
138 | if (!llseek) | |
139 | llseek = default_llseek; | |
140 | rv = llseek(file, offset, whence); | |
141 | ||
142 | pde_users_dec(pde); | |
143 | return rv; | |
144 | } | |
145 | ||
146 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
147 | { | |
148 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
149 | ssize_t rv = -EIO; | |
150 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); | |
151 | ||
152 | spin_lock(&pde->pde_unload_lock); | |
153 | if (!pde->proc_fops) { | |
154 | spin_unlock(&pde->pde_unload_lock); | |
155 | return rv; | |
156 | } | |
157 | pde->pde_users++; | |
158 | read = pde->proc_fops->read; | |
159 | spin_unlock(&pde->pde_unload_lock); | |
160 | ||
161 | if (read) | |
162 | rv = read(file, buf, count, ppos); | |
163 | ||
164 | pde_users_dec(pde); | |
165 | return rv; | |
166 | } | |
167 | ||
168 | static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
169 | { | |
170 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
171 | ssize_t rv = -EIO; | |
172 | ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); | |
173 | ||
174 | spin_lock(&pde->pde_unload_lock); | |
175 | if (!pde->proc_fops) { | |
176 | spin_unlock(&pde->pde_unload_lock); | |
177 | return rv; | |
178 | } | |
179 | pde->pde_users++; | |
180 | write = pde->proc_fops->write; | |
181 | spin_unlock(&pde->pde_unload_lock); | |
182 | ||
183 | if (write) | |
184 | rv = write(file, buf, count, ppos); | |
185 | ||
186 | pde_users_dec(pde); | |
187 | return rv; | |
188 | } | |
189 | ||
190 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
191 | { | |
192 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
dd23aae4 | 193 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 AD |
194 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
195 | ||
196 | spin_lock(&pde->pde_unload_lock); | |
197 | if (!pde->proc_fops) { | |
198 | spin_unlock(&pde->pde_unload_lock); | |
199 | return rv; | |
200 | } | |
201 | pde->pde_users++; | |
202 | poll = pde->proc_fops->poll; | |
203 | spin_unlock(&pde->pde_unload_lock); | |
204 | ||
205 | if (poll) | |
206 | rv = poll(file, pts); | |
207 | ||
208 | pde_users_dec(pde); | |
209 | return rv; | |
210 | } | |
211 | ||
212 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
213 | { | |
214 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
215 | long rv = -ENOTTY; | |
216 | long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long); | |
217 | int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long); | |
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 | unlocked_ioctl = pde->proc_fops->unlocked_ioctl; | |
226 | ioctl = pde->proc_fops->ioctl; | |
227 | spin_unlock(&pde->pde_unload_lock); | |
228 | ||
229 | if (unlocked_ioctl) { | |
230 | rv = unlocked_ioctl(file, cmd, arg); | |
231 | if (rv == -ENOIOCTLCMD) | |
232 | rv = -EINVAL; | |
233 | } else if (ioctl) { | |
234 | lock_kernel(); | |
235 | rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg); | |
236 | unlock_kernel(); | |
237 | } | |
238 | ||
239 | pde_users_dec(pde); | |
240 | return rv; | |
241 | } | |
242 | ||
243 | #ifdef CONFIG_COMPAT | |
244 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
245 | { | |
246 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
247 | long rv = -ENOTTY; | |
248 | long (*compat_ioctl)(struct file *, unsigned int, unsigned long); | |
249 | ||
250 | spin_lock(&pde->pde_unload_lock); | |
251 | if (!pde->proc_fops) { | |
252 | spin_unlock(&pde->pde_unload_lock); | |
253 | return rv; | |
254 | } | |
255 | pde->pde_users++; | |
256 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
257 | spin_unlock(&pde->pde_unload_lock); | |
258 | ||
259 | if (compat_ioctl) | |
260 | rv = compat_ioctl(file, cmd, arg); | |
261 | ||
262 | pde_users_dec(pde); | |
263 | return rv; | |
264 | } | |
265 | #endif | |
266 | ||
267 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
268 | { | |
269 | struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); | |
270 | int rv = -EIO; | |
271 | int (*mmap)(struct file *, struct vm_area_struct *); | |
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 | mmap = pde->proc_fops->mmap; | |
280 | spin_unlock(&pde->pde_unload_lock); | |
281 | ||
282 | if (mmap) | |
283 | rv = mmap(file, vma); | |
284 | ||
285 | pde_users_dec(pde); | |
286 | return rv; | |
287 | } | |
288 | ||
289 | static int proc_reg_open(struct inode *inode, struct file *file) | |
290 | { | |
291 | struct proc_dir_entry *pde = PDE(inode); | |
292 | int rv = 0; | |
293 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
294 | int (*release)(struct inode *, struct file *); |
295 | struct pde_opener *pdeo; | |
296 | ||
297 | /* | |
298 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
299 | * sequence. ->release won't be called because ->proc_fops will be | |
300 | * cleared. Depending on complexity of ->release, consequences vary. | |
301 | * | |
302 | * We can't wait for mercy when close will be done for real, it's | |
303 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
304 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
305 | * for later. | |
306 | */ | |
307 | pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); | |
308 | if (!pdeo) | |
309 | return -ENOMEM; | |
786d7e16 AD |
310 | |
311 | spin_lock(&pde->pde_unload_lock); | |
312 | if (!pde->proc_fops) { | |
313 | spin_unlock(&pde->pde_unload_lock); | |
881adb85 | 314 | kfree(pdeo); |
300b994b | 315 | return -EINVAL; |
786d7e16 AD |
316 | } |
317 | pde->pde_users++; | |
318 | open = pde->proc_fops->open; | |
881adb85 | 319 | release = pde->proc_fops->release; |
786d7e16 AD |
320 | spin_unlock(&pde->pde_unload_lock); |
321 | ||
322 | if (open) | |
323 | rv = open(inode, file); | |
324 | ||
881adb85 AD |
325 | spin_lock(&pde->pde_unload_lock); |
326 | if (rv == 0 && release) { | |
327 | /* To know what to release. */ | |
328 | pdeo->inode = inode; | |
329 | pdeo->file = file; | |
330 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
331 | pdeo->release = release; | |
332 | list_add(&pdeo->lh, &pde->pde_openers); | |
333 | } else | |
334 | kfree(pdeo); | |
335 | __pde_users_dec(pde); | |
336 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
337 | return rv; |
338 | } | |
339 | ||
881adb85 AD |
340 | static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
341 | struct inode *inode, struct file *file) | |
342 | { | |
343 | struct pde_opener *pdeo; | |
344 | ||
345 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { | |
346 | if (pdeo->inode == inode && pdeo->file == file) | |
347 | return pdeo; | |
348 | } | |
349 | return NULL; | |
350 | } | |
351 | ||
786d7e16 AD |
352 | static int proc_reg_release(struct inode *inode, struct file *file) |
353 | { | |
354 | struct proc_dir_entry *pde = PDE(inode); | |
355 | int rv = 0; | |
356 | int (*release)(struct inode *, struct file *); | |
881adb85 | 357 | struct pde_opener *pdeo; |
786d7e16 AD |
358 | |
359 | spin_lock(&pde->pde_unload_lock); | |
881adb85 | 360 | pdeo = find_pde_opener(pde, inode, file); |
786d7e16 | 361 | if (!pde->proc_fops) { |
881adb85 AD |
362 | /* |
363 | * Can't simply exit, __fput() will think that everything is OK, | |
364 | * and move on to freeing struct file. remove_proc_entry() will | |
365 | * find slacker in opener's list and will try to do non-trivial | |
366 | * things with struct file. Therefore, remove opener from list. | |
367 | * | |
368 | * But if opener is removed from list, who will ->release it? | |
369 | */ | |
370 | if (pdeo) { | |
371 | list_del(&pdeo->lh); | |
372 | spin_unlock(&pde->pde_unload_lock); | |
373 | rv = pdeo->release(inode, file); | |
374 | kfree(pdeo); | |
375 | } else | |
376 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
377 | return rv; |
378 | } | |
379 | pde->pde_users++; | |
380 | release = pde->proc_fops->release; | |
881adb85 AD |
381 | if (pdeo) { |
382 | list_del(&pdeo->lh); | |
383 | kfree(pdeo); | |
384 | } | |
786d7e16 AD |
385 | spin_unlock(&pde->pde_unload_lock); |
386 | ||
387 | if (release) | |
388 | rv = release(inode, file); | |
389 | ||
390 | pde_users_dec(pde); | |
391 | return rv; | |
392 | } | |
393 | ||
394 | static const struct file_operations proc_reg_file_ops = { | |
395 | .llseek = proc_reg_llseek, | |
396 | .read = proc_reg_read, | |
397 | .write = proc_reg_write, | |
398 | .poll = proc_reg_poll, | |
399 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
400 | #ifdef CONFIG_COMPAT | |
401 | .compat_ioctl = proc_reg_compat_ioctl, | |
402 | #endif | |
403 | .mmap = proc_reg_mmap, | |
404 | .open = proc_reg_open, | |
405 | .release = proc_reg_release, | |
406 | }; | |
407 | ||
778f3dd5 DM |
408 | #ifdef CONFIG_COMPAT |
409 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
410 | .llseek = proc_reg_llseek, | |
411 | .read = proc_reg_read, | |
412 | .write = proc_reg_write, | |
413 | .poll = proc_reg_poll, | |
414 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
415 | .mmap = proc_reg_mmap, | |
416 | .open = proc_reg_open, | |
417 | .release = proc_reg_release, | |
418 | }; | |
419 | #endif | |
420 | ||
1da177e4 LT |
421 | struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, |
422 | struct proc_dir_entry *de) | |
423 | { | |
424 | struct inode * inode; | |
425 | ||
a1d4aebb | 426 | inode = iget_locked(sb, ino); |
1da177e4 | 427 | if (!inode) |
99b76233 | 428 | return NULL; |
a1d4aebb DH |
429 | if (inode->i_state & I_NEW) { |
430 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
431 | PROC_I(inode)->fd = 0; | |
432 | PROC_I(inode)->pde = de; | |
5e971dce AD |
433 | |
434 | if (de->mode) { | |
435 | inode->i_mode = de->mode; | |
436 | inode->i_uid = de->uid; | |
437 | inode->i_gid = de->gid; | |
438 | } | |
439 | if (de->size) | |
440 | inode->i_size = de->size; | |
441 | if (de->nlink) | |
442 | inode->i_nlink = de->nlink; | |
443 | if (de->proc_iops) | |
444 | inode->i_op = de->proc_iops; | |
445 | if (de->proc_fops) { | |
446 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 447 | #ifdef CONFIG_COMPAT |
5e971dce AD |
448 | if (!de->proc_fops->compat_ioctl) |
449 | inode->i_fop = | |
450 | &proc_reg_file_ops_no_compat; | |
451 | else | |
778f3dd5 | 452 | #endif |
5e971dce AD |
453 | inode->i_fop = &proc_reg_file_ops; |
454 | } else { | |
455 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 456 | } |
786d7e16 | 457 | } |
a1d4aebb | 458 | unlock_new_inode(inode); |
99b76233 | 459 | } else |
135d5655 | 460 | pde_put(de); |
1da177e4 | 461 | return inode; |
1da177e4 LT |
462 | } |
463 | ||
07543f5c | 464 | int proc_fill_super(struct super_block *s) |
1da177e4 LT |
465 | { |
466 | struct inode * root_inode; | |
467 | ||
92d03285 | 468 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
469 | s->s_blocksize = 1024; |
470 | s->s_blocksize_bits = 10; | |
471 | s->s_magic = PROC_SUPER_MAGIC; | |
472 | s->s_op = &proc_sops; | |
473 | s->s_time_gran = 1; | |
474 | ||
135d5655 | 475 | pde_get(&proc_root); |
1da177e4 LT |
476 | root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); |
477 | if (!root_inode) | |
478 | goto out_no_root; | |
1da177e4 LT |
479 | root_inode->i_uid = 0; |
480 | root_inode->i_gid = 0; | |
481 | s->s_root = d_alloc_root(root_inode); | |
482 | if (!s->s_root) | |
483 | goto out_no_root; | |
484 | return 0; | |
485 | ||
486 | out_no_root: | |
487 | printk("proc_read_super: get root inode failed\n"); | |
488 | iput(root_inode); | |
135d5655 | 489 | pde_put(&proc_root); |
1da177e4 LT |
490 | return -ENOMEM; |
491 | } |