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> | |
97412950 | 10 | #include <linux/pid_namespace.h> |
1da177e4 LT |
11 | #include <linux/mm.h> |
12 | #include <linux/string.h> | |
13 | #include <linux/stat.h> | |
786d7e16 | 14 | #include <linux/completion.h> |
dd23aae4 | 15 | #include <linux/poll.h> |
87ebdc00 | 16 | #include <linux/printk.h> |
1da177e4 LT |
17 | #include <linux/file.h> |
18 | #include <linux/limits.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/module.h> | |
9043476f | 21 | #include <linux/sysctl.h> |
97412950 | 22 | #include <linux/seq_file.h> |
5a0e3ad6 | 23 | #include <linux/slab.h> |
97412950 | 24 | #include <linux/mount.h> |
1da177e4 | 25 | |
1da177e4 LT |
26 | #include <asm/uaccess.h> |
27 | ||
fee781e6 | 28 | #include "internal.h" |
1da177e4 | 29 | |
8267952b | 30 | static void proc_evict_inode(struct inode *inode) |
1da177e4 LT |
31 | { |
32 | struct proc_dir_entry *de; | |
dfef6dcd | 33 | struct ctl_table_header *head; |
6b4e306a | 34 | const struct proc_ns_operations *ns_ops; |
bf056bfa | 35 | void *ns; |
1da177e4 | 36 | |
fef26658 | 37 | truncate_inode_pages(&inode->i_data, 0); |
dbd5768f | 38 | clear_inode(inode); |
fef26658 | 39 | |
99f89551 | 40 | /* Stop tracking associated processes */ |
13b41b09 | 41 | put_pid(PROC_I(inode)->pid); |
1da177e4 LT |
42 | |
43 | /* Let go of any associated proc directory entry */ | |
44 | de = PROC_I(inode)->pde; | |
99b76233 | 45 | if (de) |
135d5655 | 46 | pde_put(de); |
dfef6dcd AV |
47 | head = PROC_I(inode)->sysctl; |
48 | if (head) { | |
49 | rcu_assign_pointer(PROC_I(inode)->sysctl, NULL); | |
50 | sysctl_head_put(head); | |
51 | } | |
6b4e306a EB |
52 | /* Release any associated namespace */ |
53 | ns_ops = PROC_I(inode)->ns_ops; | |
bf056bfa EB |
54 | ns = PROC_I(inode)->ns; |
55 | if (ns_ops && ns) | |
56 | ns_ops->put(ns); | |
1da177e4 LT |
57 | } |
58 | ||
e18b890b | 59 | static struct kmem_cache * proc_inode_cachep; |
1da177e4 LT |
60 | |
61 | static struct inode *proc_alloc_inode(struct super_block *sb) | |
62 | { | |
63 | struct proc_inode *ei; | |
64 | struct inode *inode; | |
65 | ||
e94b1766 | 66 | ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
67 | if (!ei) |
68 | return NULL; | |
13b41b09 | 69 | ei->pid = NULL; |
aed7a6c4 | 70 | ei->fd = 0; |
1da177e4 LT |
71 | ei->op.proc_get_link = NULL; |
72 | ei->pde = NULL; | |
9043476f AV |
73 | ei->sysctl = NULL; |
74 | ei->sysctl_entry = NULL; | |
6b4e306a EB |
75 | ei->ns = NULL; |
76 | ei->ns_ops = NULL; | |
1da177e4 LT |
77 | inode = &ei->vfs_inode; |
78 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
79 | return inode; | |
80 | } | |
81 | ||
fa0d7e3d | 82 | static void proc_i_callback(struct rcu_head *head) |
1da177e4 | 83 | { |
fa0d7e3d | 84 | struct inode *inode = container_of(head, struct inode, i_rcu); |
1da177e4 LT |
85 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); |
86 | } | |
87 | ||
fa0d7e3d NP |
88 | static void proc_destroy_inode(struct inode *inode) |
89 | { | |
90 | call_rcu(&inode->i_rcu, proc_i_callback); | |
91 | } | |
92 | ||
51cc5068 | 93 | static void init_once(void *foo) |
1da177e4 LT |
94 | { |
95 | struct proc_inode *ei = (struct proc_inode *) foo; | |
96 | ||
a35afb83 | 97 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 98 | } |
20c2df83 | 99 | |
5bcd7ff9 | 100 | void __init proc_init_inodecache(void) |
1da177e4 LT |
101 | { |
102 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
103 | sizeof(struct proc_inode), | |
fffb60f9 | 104 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 105 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 106 | init_once); |
1da177e4 LT |
107 | } |
108 | ||
97412950 VK |
109 | static int proc_show_options(struct seq_file *seq, struct dentry *root) |
110 | { | |
0499680a VK |
111 | struct super_block *sb = root->d_sb; |
112 | struct pid_namespace *pid = sb->s_fs_info; | |
113 | ||
dcb0f222 EB |
114 | if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID)) |
115 | seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid)); | |
0499680a VK |
116 | if (pid->hide_pid != 0) |
117 | seq_printf(seq, ",hidepid=%u", pid->hide_pid); | |
118 | ||
97412950 VK |
119 | return 0; |
120 | } | |
121 | ||
ee9b6d61 | 122 | static const struct super_operations proc_sops = { |
1da177e4 LT |
123 | .alloc_inode = proc_alloc_inode, |
124 | .destroy_inode = proc_destroy_inode, | |
1da177e4 | 125 | .drop_inode = generic_delete_inode, |
8267952b | 126 | .evict_inode = proc_evict_inode, |
1da177e4 | 127 | .statfs = simple_statfs, |
97412950 VK |
128 | .remount_fs = proc_remount, |
129 | .show_options = proc_show_options, | |
1da177e4 LT |
130 | }; |
131 | ||
881adb85 | 132 | static void __pde_users_dec(struct proc_dir_entry *pde) |
786d7e16 | 133 | { |
786d7e16 AD |
134 | pde->pde_users--; |
135 | if (pde->pde_unload_completion && pde->pde_users == 0) | |
136 | complete(pde->pde_unload_completion); | |
881adb85 AD |
137 | } |
138 | ||
3dec7f59 | 139 | void pde_users_dec(struct proc_dir_entry *pde) |
881adb85 AD |
140 | { |
141 | spin_lock(&pde->pde_unload_lock); | |
142 | __pde_users_dec(pde); | |
786d7e16 AD |
143 | spin_unlock(&pde->pde_unload_lock); |
144 | } | |
145 | ||
146 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) | |
147 | { | |
496ad9aa | 148 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 AD |
149 | loff_t rv = -EINVAL; |
150 | loff_t (*llseek)(struct file *, loff_t, int); | |
151 | ||
152 | spin_lock(&pde->pde_unload_lock); | |
153 | /* | |
154 | * remove_proc_entry() is going to delete PDE (as part of module | |
155 | * cleanup sequence). No new callers into module allowed. | |
156 | */ | |
157 | if (!pde->proc_fops) { | |
158 | spin_unlock(&pde->pde_unload_lock); | |
159 | return rv; | |
160 | } | |
161 | /* | |
162 | * Bump refcount so that remove_proc_entry will wail for ->llseek to | |
163 | * complete. | |
164 | */ | |
165 | pde->pde_users++; | |
166 | /* | |
167 | * Save function pointer under lock, to protect against ->proc_fops | |
168 | * NULL'ifying right after ->pde_unload_lock is dropped. | |
169 | */ | |
170 | llseek = pde->proc_fops->llseek; | |
171 | spin_unlock(&pde->pde_unload_lock); | |
172 | ||
173 | if (!llseek) | |
174 | llseek = default_llseek; | |
175 | rv = llseek(file, offset, whence); | |
176 | ||
177 | pde_users_dec(pde); | |
178 | return rv; | |
179 | } | |
180 | ||
181 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
182 | { | |
496ad9aa | 183 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 AD |
184 | ssize_t rv = -EIO; |
185 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); | |
186 | ||
187 | spin_lock(&pde->pde_unload_lock); | |
188 | if (!pde->proc_fops) { | |
189 | spin_unlock(&pde->pde_unload_lock); | |
190 | return rv; | |
191 | } | |
192 | pde->pde_users++; | |
193 | read = pde->proc_fops->read; | |
194 | spin_unlock(&pde->pde_unload_lock); | |
195 | ||
196 | if (read) | |
197 | rv = read(file, buf, count, ppos); | |
198 | ||
199 | pde_users_dec(pde); | |
200 | return rv; | |
201 | } | |
202 | ||
203 | static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
204 | { | |
496ad9aa | 205 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 AD |
206 | ssize_t rv = -EIO; |
207 | ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); | |
208 | ||
209 | spin_lock(&pde->pde_unload_lock); | |
210 | if (!pde->proc_fops) { | |
211 | spin_unlock(&pde->pde_unload_lock); | |
212 | return rv; | |
213 | } | |
214 | pde->pde_users++; | |
215 | write = pde->proc_fops->write; | |
216 | spin_unlock(&pde->pde_unload_lock); | |
217 | ||
218 | if (write) | |
219 | rv = write(file, buf, count, ppos); | |
220 | ||
221 | pde_users_dec(pde); | |
222 | return rv; | |
223 | } | |
224 | ||
225 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
226 | { | |
496ad9aa | 227 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
dd23aae4 | 228 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 AD |
229 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
230 | ||
231 | spin_lock(&pde->pde_unload_lock); | |
232 | if (!pde->proc_fops) { | |
233 | spin_unlock(&pde->pde_unload_lock); | |
234 | return rv; | |
235 | } | |
236 | pde->pde_users++; | |
237 | poll = pde->proc_fops->poll; | |
238 | spin_unlock(&pde->pde_unload_lock); | |
239 | ||
240 | if (poll) | |
241 | rv = poll(file, pts); | |
242 | ||
243 | pde_users_dec(pde); | |
244 | return rv; | |
245 | } | |
246 | ||
247 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
248 | { | |
496ad9aa | 249 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 | 250 | long rv = -ENOTTY; |
b19dd42f | 251 | long (*ioctl)(struct file *, unsigned int, unsigned long); |
786d7e16 AD |
252 | |
253 | spin_lock(&pde->pde_unload_lock); | |
254 | if (!pde->proc_fops) { | |
255 | spin_unlock(&pde->pde_unload_lock); | |
256 | return rv; | |
257 | } | |
258 | pde->pde_users++; | |
b19dd42f | 259 | ioctl = pde->proc_fops->unlocked_ioctl; |
786d7e16 AD |
260 | spin_unlock(&pde->pde_unload_lock); |
261 | ||
b19dd42f AB |
262 | if (ioctl) |
263 | rv = ioctl(file, cmd, arg); | |
786d7e16 AD |
264 | |
265 | pde_users_dec(pde); | |
266 | return rv; | |
267 | } | |
268 | ||
269 | #ifdef CONFIG_COMPAT | |
270 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
271 | { | |
496ad9aa | 272 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 AD |
273 | long rv = -ENOTTY; |
274 | long (*compat_ioctl)(struct file *, unsigned int, unsigned long); | |
275 | ||
276 | spin_lock(&pde->pde_unload_lock); | |
277 | if (!pde->proc_fops) { | |
278 | spin_unlock(&pde->pde_unload_lock); | |
279 | return rv; | |
280 | } | |
281 | pde->pde_users++; | |
282 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
283 | spin_unlock(&pde->pde_unload_lock); | |
284 | ||
285 | if (compat_ioctl) | |
286 | rv = compat_ioctl(file, cmd, arg); | |
287 | ||
288 | pde_users_dec(pde); | |
289 | return rv; | |
290 | } | |
291 | #endif | |
292 | ||
293 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
294 | { | |
496ad9aa | 295 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 AD |
296 | int rv = -EIO; |
297 | int (*mmap)(struct file *, struct vm_area_struct *); | |
298 | ||
299 | spin_lock(&pde->pde_unload_lock); | |
300 | if (!pde->proc_fops) { | |
301 | spin_unlock(&pde->pde_unload_lock); | |
302 | return rv; | |
303 | } | |
304 | pde->pde_users++; | |
305 | mmap = pde->proc_fops->mmap; | |
306 | spin_unlock(&pde->pde_unload_lock); | |
307 | ||
308 | if (mmap) | |
309 | rv = mmap(file, vma); | |
310 | ||
311 | pde_users_dec(pde); | |
312 | return rv; | |
313 | } | |
314 | ||
315 | static int proc_reg_open(struct inode *inode, struct file *file) | |
316 | { | |
317 | struct proc_dir_entry *pde = PDE(inode); | |
318 | int rv = 0; | |
319 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
320 | int (*release)(struct inode *, struct file *); |
321 | struct pde_opener *pdeo; | |
322 | ||
323 | /* | |
324 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
325 | * sequence. ->release won't be called because ->proc_fops will be | |
326 | * cleared. Depending on complexity of ->release, consequences vary. | |
327 | * | |
328 | * We can't wait for mercy when close will be done for real, it's | |
329 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
330 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
331 | * for later. | |
332 | */ | |
333 | pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL); | |
334 | if (!pdeo) | |
335 | return -ENOMEM; | |
786d7e16 AD |
336 | |
337 | spin_lock(&pde->pde_unload_lock); | |
338 | if (!pde->proc_fops) { | |
339 | spin_unlock(&pde->pde_unload_lock); | |
881adb85 | 340 | kfree(pdeo); |
d2857e79 | 341 | return -ENOENT; |
786d7e16 AD |
342 | } |
343 | pde->pde_users++; | |
344 | open = pde->proc_fops->open; | |
881adb85 | 345 | release = pde->proc_fops->release; |
786d7e16 AD |
346 | spin_unlock(&pde->pde_unload_lock); |
347 | ||
348 | if (open) | |
349 | rv = open(inode, file); | |
350 | ||
881adb85 AD |
351 | spin_lock(&pde->pde_unload_lock); |
352 | if (rv == 0 && release) { | |
353 | /* To know what to release. */ | |
354 | pdeo->inode = inode; | |
355 | pdeo->file = file; | |
356 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
357 | pdeo->release = release; | |
358 | list_add(&pdeo->lh, &pde->pde_openers); | |
359 | } else | |
360 | kfree(pdeo); | |
361 | __pde_users_dec(pde); | |
362 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
363 | return rv; |
364 | } | |
365 | ||
881adb85 AD |
366 | static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde, |
367 | struct inode *inode, struct file *file) | |
368 | { | |
369 | struct pde_opener *pdeo; | |
370 | ||
371 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { | |
372 | if (pdeo->inode == inode && pdeo->file == file) | |
373 | return pdeo; | |
374 | } | |
375 | return NULL; | |
376 | } | |
377 | ||
786d7e16 AD |
378 | static int proc_reg_release(struct inode *inode, struct file *file) |
379 | { | |
380 | struct proc_dir_entry *pde = PDE(inode); | |
381 | int rv = 0; | |
382 | int (*release)(struct inode *, struct file *); | |
881adb85 | 383 | struct pde_opener *pdeo; |
786d7e16 AD |
384 | |
385 | spin_lock(&pde->pde_unload_lock); | |
881adb85 | 386 | pdeo = find_pde_opener(pde, inode, file); |
786d7e16 | 387 | if (!pde->proc_fops) { |
881adb85 AD |
388 | /* |
389 | * Can't simply exit, __fput() will think that everything is OK, | |
390 | * and move on to freeing struct file. remove_proc_entry() will | |
391 | * find slacker in opener's list and will try to do non-trivial | |
392 | * things with struct file. Therefore, remove opener from list. | |
393 | * | |
394 | * But if opener is removed from list, who will ->release it? | |
395 | */ | |
396 | if (pdeo) { | |
397 | list_del(&pdeo->lh); | |
398 | spin_unlock(&pde->pde_unload_lock); | |
399 | rv = pdeo->release(inode, file); | |
400 | kfree(pdeo); | |
401 | } else | |
402 | spin_unlock(&pde->pde_unload_lock); | |
786d7e16 AD |
403 | return rv; |
404 | } | |
405 | pde->pde_users++; | |
406 | release = pde->proc_fops->release; | |
881adb85 AD |
407 | if (pdeo) { |
408 | list_del(&pdeo->lh); | |
409 | kfree(pdeo); | |
410 | } | |
786d7e16 AD |
411 | spin_unlock(&pde->pde_unload_lock); |
412 | ||
413 | if (release) | |
414 | rv = release(inode, file); | |
415 | ||
416 | pde_users_dec(pde); | |
417 | return rv; | |
418 | } | |
419 | ||
420 | static const struct file_operations proc_reg_file_ops = { | |
421 | .llseek = proc_reg_llseek, | |
422 | .read = proc_reg_read, | |
423 | .write = proc_reg_write, | |
424 | .poll = proc_reg_poll, | |
425 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
426 | #ifdef CONFIG_COMPAT | |
427 | .compat_ioctl = proc_reg_compat_ioctl, | |
428 | #endif | |
429 | .mmap = proc_reg_mmap, | |
430 | .open = proc_reg_open, | |
431 | .release = proc_reg_release, | |
432 | }; | |
433 | ||
778f3dd5 DM |
434 | #ifdef CONFIG_COMPAT |
435 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
436 | .llseek = proc_reg_llseek, | |
437 | .read = proc_reg_read, | |
438 | .write = proc_reg_write, | |
439 | .poll = proc_reg_poll, | |
440 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
441 | .mmap = proc_reg_mmap, | |
442 | .open = proc_reg_open, | |
443 | .release = proc_reg_release, | |
444 | }; | |
445 | #endif | |
446 | ||
6d1b6e4e | 447 | struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) |
1da177e4 | 448 | { |
d3d009cb | 449 | struct inode *inode = iget_locked(sb, de->low_ino); |
1da177e4 | 450 | |
d3d009cb | 451 | if (inode && (inode->i_state & I_NEW)) { |
a1d4aebb | 452 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
a1d4aebb | 453 | PROC_I(inode)->pde = de; |
5e971dce AD |
454 | |
455 | if (de->mode) { | |
456 | inode->i_mode = de->mode; | |
457 | inode->i_uid = de->uid; | |
458 | inode->i_gid = de->gid; | |
459 | } | |
460 | if (de->size) | |
461 | inode->i_size = de->size; | |
462 | if (de->nlink) | |
bfe86848 | 463 | set_nlink(inode, de->nlink); |
5e971dce AD |
464 | if (de->proc_iops) |
465 | inode->i_op = de->proc_iops; | |
466 | if (de->proc_fops) { | |
467 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 468 | #ifdef CONFIG_COMPAT |
5e971dce AD |
469 | if (!de->proc_fops->compat_ioctl) |
470 | inode->i_fop = | |
471 | &proc_reg_file_ops_no_compat; | |
472 | else | |
778f3dd5 | 473 | #endif |
5e971dce AD |
474 | inode->i_fop = &proc_reg_file_ops; |
475 | } else { | |
476 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 477 | } |
786d7e16 | 478 | } |
a1d4aebb | 479 | unlock_new_inode(inode); |
99b76233 | 480 | } else |
135d5655 | 481 | pde_put(de); |
1da177e4 | 482 | return inode; |
d3d009cb | 483 | } |
1da177e4 | 484 | |
07543f5c | 485 | int proc_fill_super(struct super_block *s) |
1da177e4 | 486 | { |
87e0aab3 MP |
487 | struct inode *root_inode; |
488 | ||
92d03285 | 489 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
490 | s->s_blocksize = 1024; |
491 | s->s_blocksize_bits = 10; | |
492 | s->s_magic = PROC_SUPER_MAGIC; | |
493 | s->s_op = &proc_sops; | |
494 | s->s_time_gran = 1; | |
495 | ||
135d5655 | 496 | pde_get(&proc_root); |
87e0aab3 MP |
497 | root_inode = proc_get_inode(s, &proc_root); |
498 | if (!root_inode) { | |
87ebdc00 | 499 | pr_err("proc_fill_super: get root inode failed\n"); |
87e0aab3 MP |
500 | return -ENOMEM; |
501 | } | |
1da177e4 | 502 | |
87e0aab3 MP |
503 | s->s_root = d_make_root(root_inode); |
504 | if (!s->s_root) { | |
87ebdc00 | 505 | pr_err("proc_fill_super: allocate dentry failed\n"); |
87e0aab3 MP |
506 | return -ENOMEM; |
507 | } | |
508 | ||
509 | return 0; | |
1da177e4 | 510 | } |