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> |
303eb7e2 | 25 | #include <linux/magic.h> |
1da177e4 | 26 | |
1da177e4 LT |
27 | #include <asm/uaccess.h> |
28 | ||
fee781e6 | 29 | #include "internal.h" |
1da177e4 | 30 | |
8267952b | 31 | static void proc_evict_inode(struct inode *inode) |
1da177e4 LT |
32 | { |
33 | struct proc_dir_entry *de; | |
dfef6dcd | 34 | struct ctl_table_header *head; |
6b4e306a | 35 | const struct proc_ns_operations *ns_ops; |
bf056bfa | 36 | void *ns; |
1da177e4 | 37 | |
91b0abe3 | 38 | truncate_inode_pages_final(&inode->i_data); |
dbd5768f | 39 | clear_inode(inode); |
fef26658 | 40 | |
99f89551 | 41 | /* Stop tracking associated processes */ |
13b41b09 | 42 | put_pid(PROC_I(inode)->pid); |
1da177e4 LT |
43 | |
44 | /* Let go of any associated proc directory entry */ | |
45 | de = PROC_I(inode)->pde; | |
99b76233 | 46 | if (de) |
135d5655 | 47 | pde_put(de); |
dfef6dcd AV |
48 | head = PROC_I(inode)->sysctl; |
49 | if (head) { | |
1c44dbc8 | 50 | RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL); |
dfef6dcd AV |
51 | sysctl_head_put(head); |
52 | } | |
6b4e306a | 53 | /* Release any associated namespace */ |
0bb80f24 DH |
54 | ns_ops = PROC_I(inode)->ns.ns_ops; |
55 | ns = PROC_I(inode)->ns.ns; | |
bf056bfa EB |
56 | if (ns_ops && ns) |
57 | ns_ops->put(ns); | |
1da177e4 LT |
58 | } |
59 | ||
e18b890b | 60 | static struct kmem_cache * proc_inode_cachep; |
1da177e4 LT |
61 | |
62 | static struct inode *proc_alloc_inode(struct super_block *sb) | |
63 | { | |
64 | struct proc_inode *ei; | |
65 | struct inode *inode; | |
66 | ||
e94b1766 | 67 | ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
68 | if (!ei) |
69 | return NULL; | |
13b41b09 | 70 | ei->pid = NULL; |
aed7a6c4 | 71 | ei->fd = 0; |
1da177e4 LT |
72 | ei->op.proc_get_link = NULL; |
73 | ei->pde = NULL; | |
9043476f AV |
74 | ei->sysctl = NULL; |
75 | ei->sysctl_entry = NULL; | |
0bb80f24 DH |
76 | ei->ns.ns = NULL; |
77 | ei->ns.ns_ops = NULL; | |
1da177e4 LT |
78 | inode = &ei->vfs_inode; |
79 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
80 | return inode; | |
81 | } | |
82 | ||
fa0d7e3d | 83 | static void proc_i_callback(struct rcu_head *head) |
1da177e4 | 84 | { |
fa0d7e3d | 85 | struct inode *inode = container_of(head, struct inode, i_rcu); |
1da177e4 LT |
86 | kmem_cache_free(proc_inode_cachep, PROC_I(inode)); |
87 | } | |
88 | ||
fa0d7e3d NP |
89 | static void proc_destroy_inode(struct inode *inode) |
90 | { | |
91 | call_rcu(&inode->i_rcu, proc_i_callback); | |
92 | } | |
93 | ||
51cc5068 | 94 | static void init_once(void *foo) |
1da177e4 LT |
95 | { |
96 | struct proc_inode *ei = (struct proc_inode *) foo; | |
97 | ||
a35afb83 | 98 | inode_init_once(&ei->vfs_inode); |
1da177e4 | 99 | } |
20c2df83 | 100 | |
5bcd7ff9 | 101 | void __init proc_init_inodecache(void) |
1da177e4 LT |
102 | { |
103 | proc_inode_cachep = kmem_cache_create("proc_inode_cache", | |
104 | sizeof(struct proc_inode), | |
fffb60f9 | 105 | 0, (SLAB_RECLAIM_ACCOUNT| |
040b5c6f | 106 | SLAB_MEM_SPREAD|SLAB_PANIC), |
20c2df83 | 107 | init_once); |
1da177e4 LT |
108 | } |
109 | ||
97412950 VK |
110 | static int proc_show_options(struct seq_file *seq, struct dentry *root) |
111 | { | |
0499680a VK |
112 | struct super_block *sb = root->d_sb; |
113 | struct pid_namespace *pid = sb->s_fs_info; | |
114 | ||
dcb0f222 EB |
115 | if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID)) |
116 | seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid)); | |
0499680a VK |
117 | if (pid->hide_pid != 0) |
118 | seq_printf(seq, ",hidepid=%u", pid->hide_pid); | |
119 | ||
97412950 VK |
120 | return 0; |
121 | } | |
122 | ||
ee9b6d61 | 123 | static const struct super_operations proc_sops = { |
1da177e4 LT |
124 | .alloc_inode = proc_alloc_inode, |
125 | .destroy_inode = proc_destroy_inode, | |
1da177e4 | 126 | .drop_inode = generic_delete_inode, |
8267952b | 127 | .evict_inode = proc_evict_inode, |
1da177e4 | 128 | .statfs = simple_statfs, |
97412950 VK |
129 | .remount_fs = proc_remount, |
130 | .show_options = proc_show_options, | |
1da177e4 LT |
131 | }; |
132 | ||
866ad9a7 AV |
133 | enum {BIAS = -1U<<31}; |
134 | ||
135 | static inline int use_pde(struct proc_dir_entry *pde) | |
136 | { | |
05c0ae21 | 137 | return atomic_inc_unless_negative(&pde->in_use); |
881adb85 AD |
138 | } |
139 | ||
866ad9a7 | 140 | static void unuse_pde(struct proc_dir_entry *pde) |
881adb85 | 141 | { |
05c0ae21 AV |
142 | if (atomic_dec_return(&pde->in_use) == BIAS) |
143 | complete(pde->pde_unload_completion); | |
786d7e16 AD |
144 | } |
145 | ||
ca469f35 AV |
146 | /* pde is locked */ |
147 | static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo) | |
148 | { | |
05c0ae21 | 149 | if (pdeo->closing) { |
ca469f35 | 150 | /* somebody else is doing that, just wait */ |
05c0ae21 AV |
151 | DECLARE_COMPLETION_ONSTACK(c); |
152 | pdeo->c = &c; | |
ca469f35 | 153 | spin_unlock(&pde->pde_unload_lock); |
05c0ae21 | 154 | wait_for_completion(&c); |
ca469f35 | 155 | spin_lock(&pde->pde_unload_lock); |
ca469f35 AV |
156 | } else { |
157 | struct file *file; | |
05c0ae21 | 158 | pdeo->closing = 1; |
ca469f35 AV |
159 | spin_unlock(&pde->pde_unload_lock); |
160 | file = pdeo->file; | |
161 | pde->proc_fops->release(file_inode(file), file); | |
162 | spin_lock(&pde->pde_unload_lock); | |
163 | list_del_init(&pdeo->lh); | |
05c0ae21 AV |
164 | if (pdeo->c) |
165 | complete(pdeo->c); | |
ca469f35 | 166 | kfree(pdeo); |
05c0ae21 | 167 | } |
ca469f35 AV |
168 | } |
169 | ||
866ad9a7 | 170 | void proc_entry_rundown(struct proc_dir_entry *de) |
786d7e16 | 171 | { |
05c0ae21 | 172 | DECLARE_COMPLETION_ONSTACK(c); |
866ad9a7 | 173 | /* Wait until all existing callers into module are done. */ |
05c0ae21 AV |
174 | de->pde_unload_completion = &c; |
175 | if (atomic_add_return(BIAS, &de->in_use) != BIAS) | |
176 | wait_for_completion(&c); | |
786d7e16 | 177 | |
05c0ae21 | 178 | spin_lock(&de->pde_unload_lock); |
866ad9a7 AV |
179 | while (!list_empty(&de->pde_openers)) { |
180 | struct pde_opener *pdeo; | |
866ad9a7 | 181 | pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh); |
ca469f35 | 182 | close_pdeo(de, pdeo); |
866ad9a7 AV |
183 | } |
184 | spin_unlock(&de->pde_unload_lock); | |
786d7e16 AD |
185 | } |
186 | ||
866ad9a7 AV |
187 | static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) |
188 | { | |
189 | struct proc_dir_entry *pde = PDE(file_inode(file)); | |
190 | loff_t rv = -EINVAL; | |
191 | if (use_pde(pde)) { | |
192 | loff_t (*llseek)(struct file *, loff_t, int); | |
193 | llseek = pde->proc_fops->llseek; | |
194 | if (!llseek) | |
195 | llseek = default_llseek; | |
196 | rv = llseek(file, offset, whence); | |
197 | unuse_pde(pde); | |
198 | } | |
786d7e16 AD |
199 | return rv; |
200 | } | |
201 | ||
866ad9a7 | 202 | static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
786d7e16 | 203 | { |
866ad9a7 | 204 | ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); |
496ad9aa | 205 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 | 206 | ssize_t rv = -EIO; |
866ad9a7 AV |
207 | if (use_pde(pde)) { |
208 | read = pde->proc_fops->read; | |
209 | if (read) | |
210 | rv = read(file, buf, count, ppos); | |
211 | unuse_pde(pde); | |
786d7e16 | 212 | } |
866ad9a7 AV |
213 | return rv; |
214 | } | |
786d7e16 | 215 | |
866ad9a7 AV |
216 | static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) |
217 | { | |
218 | ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); | |
219 | struct proc_dir_entry *pde = PDE(file_inode(file)); | |
220 | ssize_t rv = -EIO; | |
221 | if (use_pde(pde)) { | |
222 | write = pde->proc_fops->write; | |
223 | if (write) | |
224 | rv = write(file, buf, count, ppos); | |
225 | unuse_pde(pde); | |
226 | } | |
786d7e16 AD |
227 | return rv; |
228 | } | |
229 | ||
230 | static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) | |
231 | { | |
496ad9aa | 232 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
dd23aae4 | 233 | unsigned int rv = DEFAULT_POLLMASK; |
786d7e16 | 234 | unsigned int (*poll)(struct file *, struct poll_table_struct *); |
866ad9a7 AV |
235 | if (use_pde(pde)) { |
236 | poll = pde->proc_fops->poll; | |
237 | if (poll) | |
238 | rv = poll(file, pts); | |
239 | unuse_pde(pde); | |
786d7e16 | 240 | } |
786d7e16 AD |
241 | return rv; |
242 | } | |
243 | ||
244 | static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
245 | { | |
496ad9aa | 246 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 | 247 | long rv = -ENOTTY; |
b19dd42f | 248 | long (*ioctl)(struct file *, unsigned int, unsigned long); |
866ad9a7 AV |
249 | if (use_pde(pde)) { |
250 | ioctl = pde->proc_fops->unlocked_ioctl; | |
251 | if (ioctl) | |
252 | rv = ioctl(file, cmd, arg); | |
253 | unuse_pde(pde); | |
786d7e16 | 254 | } |
786d7e16 AD |
255 | return rv; |
256 | } | |
257 | ||
258 | #ifdef CONFIG_COMPAT | |
259 | static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
260 | { | |
496ad9aa | 261 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 AD |
262 | long rv = -ENOTTY; |
263 | long (*compat_ioctl)(struct file *, unsigned int, unsigned long); | |
866ad9a7 AV |
264 | if (use_pde(pde)) { |
265 | compat_ioctl = pde->proc_fops->compat_ioctl; | |
266 | if (compat_ioctl) | |
267 | rv = compat_ioctl(file, cmd, arg); | |
268 | unuse_pde(pde); | |
786d7e16 | 269 | } |
786d7e16 AD |
270 | return rv; |
271 | } | |
272 | #endif | |
273 | ||
274 | static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) | |
275 | { | |
496ad9aa | 276 | struct proc_dir_entry *pde = PDE(file_inode(file)); |
786d7e16 AD |
277 | int rv = -EIO; |
278 | int (*mmap)(struct file *, struct vm_area_struct *); | |
866ad9a7 AV |
279 | if (use_pde(pde)) { |
280 | mmap = pde->proc_fops->mmap; | |
281 | if (mmap) | |
282 | rv = mmap(file, vma); | |
283 | unuse_pde(pde); | |
786d7e16 | 284 | } |
786d7e16 AD |
285 | return rv; |
286 | } | |
287 | ||
5721cf84 HD |
288 | static unsigned long |
289 | proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr, | |
290 | unsigned long len, unsigned long pgoff, | |
291 | unsigned long flags) | |
c4fe2448 AD |
292 | { |
293 | struct proc_dir_entry *pde = PDE(file_inode(file)); | |
2cbe3b0a | 294 | unsigned long rv = -EIO; |
ae5758a1 | 295 | |
c4fe2448 | 296 | if (use_pde(pde)) { |
ae5758a1 JB |
297 | typeof(proc_reg_get_unmapped_area) *get_area; |
298 | ||
299 | get_area = pde->proc_fops->get_unmapped_area; | |
fad1a86e | 300 | #ifdef CONFIG_MMU |
ae5758a1 JB |
301 | if (!get_area) |
302 | get_area = current->mm->get_unmapped_area; | |
fad1a86e | 303 | #endif |
ae5758a1 | 304 | |
5721cf84 HD |
305 | if (get_area) |
306 | rv = get_area(file, orig_addr, len, pgoff, flags); | |
ae5758a1 JB |
307 | else |
308 | rv = orig_addr; | |
c4fe2448 AD |
309 | unuse_pde(pde); |
310 | } | |
311 | return rv; | |
312 | } | |
313 | ||
786d7e16 AD |
314 | static int proc_reg_open(struct inode *inode, struct file *file) |
315 | { | |
316 | struct proc_dir_entry *pde = PDE(inode); | |
317 | int rv = 0; | |
318 | int (*open)(struct inode *, struct file *); | |
881adb85 AD |
319 | int (*release)(struct inode *, struct file *); |
320 | struct pde_opener *pdeo; | |
321 | ||
322 | /* | |
323 | * What for, you ask? Well, we can have open, rmmod, remove_proc_entry | |
324 | * sequence. ->release won't be called because ->proc_fops will be | |
325 | * cleared. Depending on complexity of ->release, consequences vary. | |
326 | * | |
327 | * We can't wait for mercy when close will be done for real, it's | |
328 | * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release | |
329 | * by hand in remove_proc_entry(). For this, save opener's credentials | |
330 | * for later. | |
331 | */ | |
05c0ae21 | 332 | pdeo = kzalloc(sizeof(struct pde_opener), GFP_KERNEL); |
881adb85 AD |
333 | if (!pdeo) |
334 | return -ENOMEM; | |
786d7e16 | 335 | |
866ad9a7 | 336 | if (!use_pde(pde)) { |
881adb85 | 337 | kfree(pdeo); |
d2857e79 | 338 | return -ENOENT; |
786d7e16 | 339 | } |
786d7e16 | 340 | open = pde->proc_fops->open; |
881adb85 | 341 | release = pde->proc_fops->release; |
786d7e16 AD |
342 | |
343 | if (open) | |
344 | rv = open(inode, file); | |
345 | ||
881adb85 AD |
346 | if (rv == 0 && release) { |
347 | /* To know what to release. */ | |
881adb85 AD |
348 | pdeo->file = file; |
349 | /* Strictly for "too late" ->release in proc_reg_release(). */ | |
05c0ae21 | 350 | spin_lock(&pde->pde_unload_lock); |
881adb85 | 351 | list_add(&pdeo->lh, &pde->pde_openers); |
05c0ae21 | 352 | spin_unlock(&pde->pde_unload_lock); |
881adb85 AD |
353 | } else |
354 | kfree(pdeo); | |
05c0ae21 AV |
355 | |
356 | unuse_pde(pde); | |
786d7e16 AD |
357 | return rv; |
358 | } | |
359 | ||
360 | static int proc_reg_release(struct inode *inode, struct file *file) | |
361 | { | |
362 | struct proc_dir_entry *pde = PDE(inode); | |
881adb85 | 363 | struct pde_opener *pdeo; |
786d7e16 | 364 | spin_lock(&pde->pde_unload_lock); |
ca469f35 AV |
365 | list_for_each_entry(pdeo, &pde->pde_openers, lh) { |
366 | if (pdeo->file == file) { | |
367 | close_pdeo(pde, pdeo); | |
368 | break; | |
369 | } | |
881adb85 | 370 | } |
786d7e16 | 371 | spin_unlock(&pde->pde_unload_lock); |
ca469f35 | 372 | return 0; |
786d7e16 AD |
373 | } |
374 | ||
375 | static const struct file_operations proc_reg_file_ops = { | |
376 | .llseek = proc_reg_llseek, | |
377 | .read = proc_reg_read, | |
378 | .write = proc_reg_write, | |
379 | .poll = proc_reg_poll, | |
380 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
381 | #ifdef CONFIG_COMPAT | |
382 | .compat_ioctl = proc_reg_compat_ioctl, | |
383 | #endif | |
384 | .mmap = proc_reg_mmap, | |
c4fe2448 | 385 | .get_unmapped_area = proc_reg_get_unmapped_area, |
786d7e16 AD |
386 | .open = proc_reg_open, |
387 | .release = proc_reg_release, | |
388 | }; | |
389 | ||
778f3dd5 DM |
390 | #ifdef CONFIG_COMPAT |
391 | static const struct file_operations proc_reg_file_ops_no_compat = { | |
392 | .llseek = proc_reg_llseek, | |
393 | .read = proc_reg_read, | |
394 | .write = proc_reg_write, | |
395 | .poll = proc_reg_poll, | |
396 | .unlocked_ioctl = proc_reg_unlocked_ioctl, | |
397 | .mmap = proc_reg_mmap, | |
c4fe2448 | 398 | .get_unmapped_area = proc_reg_get_unmapped_area, |
778f3dd5 DM |
399 | .open = proc_reg_open, |
400 | .release = proc_reg_release, | |
401 | }; | |
402 | #endif | |
403 | ||
6d1b6e4e | 404 | struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) |
1da177e4 | 405 | { |
51f0885e | 406 | struct inode *inode = new_inode_pseudo(sb); |
1da177e4 | 407 | |
51f0885e LT |
408 | if (inode) { |
409 | inode->i_ino = de->low_ino; | |
a1d4aebb | 410 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
a1d4aebb | 411 | PROC_I(inode)->pde = de; |
5e971dce AD |
412 | |
413 | if (de->mode) { | |
414 | inode->i_mode = de->mode; | |
415 | inode->i_uid = de->uid; | |
416 | inode->i_gid = de->gid; | |
417 | } | |
418 | if (de->size) | |
419 | inode->i_size = de->size; | |
420 | if (de->nlink) | |
bfe86848 | 421 | set_nlink(inode, de->nlink); |
b6cdc731 AV |
422 | WARN_ON(!de->proc_iops); |
423 | inode->i_op = de->proc_iops; | |
5e971dce AD |
424 | if (de->proc_fops) { |
425 | if (S_ISREG(inode->i_mode)) { | |
778f3dd5 | 426 | #ifdef CONFIG_COMPAT |
5e971dce AD |
427 | if (!de->proc_fops->compat_ioctl) |
428 | inode->i_fop = | |
429 | &proc_reg_file_ops_no_compat; | |
430 | else | |
778f3dd5 | 431 | #endif |
5e971dce AD |
432 | inode->i_fop = &proc_reg_file_ops; |
433 | } else { | |
434 | inode->i_fop = de->proc_fops; | |
778f3dd5 | 435 | } |
786d7e16 | 436 | } |
99b76233 | 437 | } else |
135d5655 | 438 | pde_put(de); |
1da177e4 | 439 | return inode; |
d3d009cb | 440 | } |
1da177e4 | 441 | |
07543f5c | 442 | int proc_fill_super(struct super_block *s) |
1da177e4 | 443 | { |
87e0aab3 MP |
444 | struct inode *root_inode; |
445 | ||
92d03285 | 446 | s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; |
1da177e4 LT |
447 | s->s_blocksize = 1024; |
448 | s->s_blocksize_bits = 10; | |
449 | s->s_magic = PROC_SUPER_MAGIC; | |
450 | s->s_op = &proc_sops; | |
451 | s->s_time_gran = 1; | |
452 | ||
135d5655 | 453 | pde_get(&proc_root); |
87e0aab3 MP |
454 | root_inode = proc_get_inode(s, &proc_root); |
455 | if (!root_inode) { | |
87ebdc00 | 456 | pr_err("proc_fill_super: get root inode failed\n"); |
87e0aab3 MP |
457 | return -ENOMEM; |
458 | } | |
1da177e4 | 459 | |
87e0aab3 MP |
460 | s->s_root = d_make_root(root_inode); |
461 | if (!s->s_root) { | |
87ebdc00 | 462 | pr_err("proc_fill_super: allocate dentry failed\n"); |
87e0aab3 MP |
463 | return -ENOMEM; |
464 | } | |
465 | ||
021ada7d | 466 | return proc_setup_self(s); |
1da177e4 | 467 | } |