blob: b08d10017911f43927646943307e26238e4fe7dc [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Alexey Dobriyan786d7e12007-07-15 23:39:00 -070013#include <linux/completion.h>
Alexey Dobriyandd23aae2007-09-11 15:23:55 -070014#include <linux/poll.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#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>
20
21#include <asm/system.h>
22#include <asm/uaccess.h>
23
Adrian Bunkfee781e2006-01-08 01:04:16 -080024#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
Alexey Dobriyan76956502007-05-08 00:25:45 -070026struct proc_dir_entry *de_get(struct proc_dir_entry *de)
Linus Torvalds1da177e2005-04-16 15:20:36 -070027{
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -070028 atomic_inc(&de->count);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 return de;
30}
31
32/*
33 * Decrements the use count and checks for deferred deletion.
34 */
Alexey Dobriyan76956502007-05-08 00:25:45 -070035void de_put(struct proc_dir_entry *de)
Linus Torvalds1da177e2005-04-16 15:20:36 -070036{
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -070037 lock_kernel();
38 if (!atomic_read(&de->count)) {
39 printk("de_put: entry %s already free!\n", de->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 unlock_kernel();
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -070041 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 }
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -070043
44 if (atomic_dec_and_test(&de->count))
45 free_proc_entry(de);
46 unlock_kernel();
Linus Torvalds1da177e2005-04-16 15:20:36 -070047}
48
49/*
50 * Decrement the use count of the proc_dir_entry.
51 */
52static void proc_delete_inode(struct inode *inode)
53{
54 struct proc_dir_entry *de;
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
Mark Fashehfef26652005-09-09 13:01:31 -070056 truncate_inode_pages(&inode->i_data, 0);
57
Eric W. Biederman99f89552006-06-26 00:25:55 -070058 /* Stop tracking associated processes */
Eric W. Biederman13b41b02006-06-26 00:25:56 -070059 put_pid(PROC_I(inode)->pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61 /* Let go of any associated proc directory entry */
62 de = PROC_I(inode)->pde;
63 if (de) {
64 if (de->owner)
65 module_put(de->owner);
66 de_put(de);
67 }
68 clear_inode(inode);
69}
70
71struct vfsmount *proc_mnt;
72
Christoph Lametere18b8902006-12-06 20:33:20 -080073static struct kmem_cache * proc_inode_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
75static struct inode *proc_alloc_inode(struct super_block *sb)
76{
77 struct proc_inode *ei;
78 struct inode *inode;
79
Christoph Lametere94b1762006-12-06 20:33:17 -080080 ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 if (!ei)
82 return NULL;
Eric W. Biederman13b41b02006-06-26 00:25:56 -070083 ei->pid = NULL;
Eric W. Biedermanaed7a6c2006-06-26 00:25:44 -070084 ei->fd = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 ei->op.proc_get_link = NULL;
86 ei->pde = NULL;
87 inode = &ei->vfs_inode;
88 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
89 return inode;
90}
91
92static void proc_destroy_inode(struct inode *inode)
93{
94 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
95}
96
Christoph Lameter4ba9b9d2007-10-16 23:25:51 -070097static void init_once(struct kmem_cache * cachep, void *foo)
Linus Torvalds1da177e2005-04-16 15:20:36 -070098{
99 struct proc_inode *ei = (struct proc_inode *) foo;
100
Christoph Lametera35afb82007-05-16 22:10:57 -0700101 inode_init_once(&ei->vfs_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102}
Paul Mundt20c2df82007-07-20 10:11:58 +0900103
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104int __init proc_init_inodecache(void)
105{
106 proc_inode_cachep = kmem_cache_create("proc_inode_cache",
107 sizeof(struct proc_inode),
Paul Jacksonfffb60f2006-03-24 03:16:06 -0800108 0, (SLAB_RECLAIM_ACCOUNT|
Alexey Dobriyan040b5c62007-10-16 23:26:10 -0700109 SLAB_MEM_SPREAD|SLAB_PANIC),
Paul Mundt20c2df82007-07-20 10:11:58 +0900110 init_once);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 return 0;
112}
113
114static int proc_remount(struct super_block *sb, int *flags, char *data)
115{
116 *flags |= MS_NODIRATIME;
117 return 0;
118}
119
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800120static const struct super_operations proc_sops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 .alloc_inode = proc_alloc_inode,
122 .destroy_inode = proc_destroy_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 .drop_inode = generic_delete_inode,
124 .delete_inode = proc_delete_inode,
125 .statfs = simple_statfs,
126 .remount_fs = proc_remount,
127};
128
Alexey Dobriyan786d7e12007-07-15 23:39:00 -0700129static void pde_users_dec(struct proc_dir_entry *pde)
130{
131 spin_lock(&pde->pde_unload_lock);
132 pde->pde_users--;
133 if (pde->pde_unload_completion && pde->pde_users == 0)
134 complete(pde->pde_unload_completion);
135 spin_unlock(&pde->pde_unload_lock);
136}
137
138static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
139{
140 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
141 loff_t rv = -EINVAL;
142 loff_t (*llseek)(struct file *, loff_t, int);
143
144 spin_lock(&pde->pde_unload_lock);
145 /*
146 * remove_proc_entry() is going to delete PDE (as part of module
147 * cleanup sequence). No new callers into module allowed.
148 */
149 if (!pde->proc_fops) {
150 spin_unlock(&pde->pde_unload_lock);
151 return rv;
152 }
153 /*
154 * Bump refcount so that remove_proc_entry will wail for ->llseek to
155 * complete.
156 */
157 pde->pde_users++;
158 /*
159 * Save function pointer under lock, to protect against ->proc_fops
160 * NULL'ifying right after ->pde_unload_lock is dropped.
161 */
162 llseek = pde->proc_fops->llseek;
163 spin_unlock(&pde->pde_unload_lock);
164
165 if (!llseek)
166 llseek = default_llseek;
167 rv = llseek(file, offset, whence);
168
169 pde_users_dec(pde);
170 return rv;
171}
172
173static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
174{
175 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
176 ssize_t rv = -EIO;
177 ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
178
179 spin_lock(&pde->pde_unload_lock);
180 if (!pde->proc_fops) {
181 spin_unlock(&pde->pde_unload_lock);
182 return rv;
183 }
184 pde->pde_users++;
185 read = pde->proc_fops->read;
186 spin_unlock(&pde->pde_unload_lock);
187
188 if (read)
189 rv = read(file, buf, count, ppos);
190
191 pde_users_dec(pde);
192 return rv;
193}
194
195static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
196{
197 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
198 ssize_t rv = -EIO;
199 ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
200
201 spin_lock(&pde->pde_unload_lock);
202 if (!pde->proc_fops) {
203 spin_unlock(&pde->pde_unload_lock);
204 return rv;
205 }
206 pde->pde_users++;
207 write = pde->proc_fops->write;
208 spin_unlock(&pde->pde_unload_lock);
209
210 if (write)
211 rv = write(file, buf, count, ppos);
212
213 pde_users_dec(pde);
214 return rv;
215}
216
217static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
218{
219 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
Alexey Dobriyandd23aae2007-09-11 15:23:55 -0700220 unsigned int rv = DEFAULT_POLLMASK;
Alexey Dobriyan786d7e12007-07-15 23:39:00 -0700221 unsigned int (*poll)(struct file *, struct poll_table_struct *);
222
223 spin_lock(&pde->pde_unload_lock);
224 if (!pde->proc_fops) {
225 spin_unlock(&pde->pde_unload_lock);
226 return rv;
227 }
228 pde->pde_users++;
229 poll = pde->proc_fops->poll;
230 spin_unlock(&pde->pde_unload_lock);
231
232 if (poll)
233 rv = poll(file, pts);
234
235 pde_users_dec(pde);
236 return rv;
237}
238
239static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
240{
241 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
242 long rv = -ENOTTY;
243 long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long);
244 int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long);
245
246 spin_lock(&pde->pde_unload_lock);
247 if (!pde->proc_fops) {
248 spin_unlock(&pde->pde_unload_lock);
249 return rv;
250 }
251 pde->pde_users++;
252 unlocked_ioctl = pde->proc_fops->unlocked_ioctl;
253 ioctl = pde->proc_fops->ioctl;
254 spin_unlock(&pde->pde_unload_lock);
255
256 if (unlocked_ioctl) {
257 rv = unlocked_ioctl(file, cmd, arg);
258 if (rv == -ENOIOCTLCMD)
259 rv = -EINVAL;
260 } else if (ioctl) {
261 lock_kernel();
262 rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
263 unlock_kernel();
264 }
265
266 pde_users_dec(pde);
267 return rv;
268}
269
270#ifdef CONFIG_COMPAT
271static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
272{
273 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
274 long rv = -ENOTTY;
275 long (*compat_ioctl)(struct file *, unsigned int, unsigned long);
276
277 spin_lock(&pde->pde_unload_lock);
278 if (!pde->proc_fops) {
279 spin_unlock(&pde->pde_unload_lock);
280 return rv;
281 }
282 pde->pde_users++;
283 compat_ioctl = pde->proc_fops->compat_ioctl;
284 spin_unlock(&pde->pde_unload_lock);
285
286 if (compat_ioctl)
287 rv = compat_ioctl(file, cmd, arg);
288
289 pde_users_dec(pde);
290 return rv;
291}
292#endif
293
294static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
295{
296 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
297 int rv = -EIO;
298 int (*mmap)(struct file *, struct vm_area_struct *);
299
300 spin_lock(&pde->pde_unload_lock);
301 if (!pde->proc_fops) {
302 spin_unlock(&pde->pde_unload_lock);
303 return rv;
304 }
305 pde->pde_users++;
306 mmap = pde->proc_fops->mmap;
307 spin_unlock(&pde->pde_unload_lock);
308
309 if (mmap)
310 rv = mmap(file, vma);
311
312 pde_users_dec(pde);
313 return rv;
314}
315
316static int proc_reg_open(struct inode *inode, struct file *file)
317{
318 struct proc_dir_entry *pde = PDE(inode);
319 int rv = 0;
320 int (*open)(struct inode *, struct file *);
321
322 spin_lock(&pde->pde_unload_lock);
323 if (!pde->proc_fops) {
324 spin_unlock(&pde->pde_unload_lock);
325 return rv;
326 }
327 pde->pde_users++;
328 open = pde->proc_fops->open;
329 spin_unlock(&pde->pde_unload_lock);
330
331 if (open)
332 rv = open(inode, file);
333
334 pde_users_dec(pde);
335 return rv;
336}
337
338static int proc_reg_release(struct inode *inode, struct file *file)
339{
340 struct proc_dir_entry *pde = PDE(inode);
341 int rv = 0;
342 int (*release)(struct inode *, struct file *);
343
344 spin_lock(&pde->pde_unload_lock);
345 if (!pde->proc_fops) {
346 spin_unlock(&pde->pde_unload_lock);
347 return rv;
348 }
349 pde->pde_users++;
350 release = pde->proc_fops->release;
351 spin_unlock(&pde->pde_unload_lock);
352
353 if (release)
354 rv = release(inode, file);
355
356 pde_users_dec(pde);
357 return rv;
358}
359
360static const struct file_operations proc_reg_file_ops = {
361 .llseek = proc_reg_llseek,
362 .read = proc_reg_read,
363 .write = proc_reg_write,
364 .poll = proc_reg_poll,
365 .unlocked_ioctl = proc_reg_unlocked_ioctl,
366#ifdef CONFIG_COMPAT
367 .compat_ioctl = proc_reg_compat_ioctl,
368#endif
369 .mmap = proc_reg_mmap,
370 .open = proc_reg_open,
371 .release = proc_reg_release,
372};
373
David Miller778f3dd2007-07-27 22:58:37 -0700374#ifdef CONFIG_COMPAT
375static const struct file_operations proc_reg_file_ops_no_compat = {
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 .mmap = proc_reg_mmap,
382 .open = proc_reg_open,
383 .release = proc_reg_release,
384};
385#endif
386
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
388 struct proc_dir_entry *de)
389{
390 struct inode * inode;
391
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700392 if (!try_module_get(de->owner))
Kirill Korotaeve9543652005-10-30 15:02:26 -0800393 goto out_mod;
394
David Howellsa1d4aeb2008-02-07 00:15:45 -0800395 inode = iget_locked(sb, ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 if (!inode)
Kirill Korotaeve9543652005-10-30 15:02:26 -0800397 goto out_ino;
David Howellsa1d4aeb2008-02-07 00:15:45 -0800398 if (inode->i_state & I_NEW) {
399 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
400 PROC_I(inode)->fd = 0;
401 PROC_I(inode)->pde = de;
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700402
403 if (de->mode) {
404 inode->i_mode = de->mode;
405 inode->i_uid = de->uid;
406 inode->i_gid = de->gid;
407 }
408 if (de->size)
409 inode->i_size = de->size;
410 if (de->nlink)
411 inode->i_nlink = de->nlink;
412 if (de->proc_iops)
413 inode->i_op = de->proc_iops;
414 if (de->proc_fops) {
415 if (S_ISREG(inode->i_mode)) {
David Howellsa1d4aeb2008-02-07 00:15:45 -0800416#ifdef CONFIG_COMPAT
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700417 if (!de->proc_fops->compat_ioctl)
418 inode->i_fop =
419 &proc_reg_file_ops_no_compat;
420 else
David Howellsa1d4aeb2008-02-07 00:15:45 -0800421#endif
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700422 inode->i_fop = &proc_reg_file_ops;
423 } else {
424 inode->i_fop = de->proc_fops;
David Howellsa1d4aeb2008-02-07 00:15:45 -0800425 }
Alexey Dobriyan786d7e12007-07-15 23:39:00 -0700426 }
David Howellsa1d4aeb2008-02-07 00:15:45 -0800427 unlock_new_inode(inode);
Denis V. Lunevc4185a02008-05-23 13:04:47 -0700428 } else
429 module_put(de->owner);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 return inode;
431
Kirill Korotaeve9543652005-10-30 15:02:26 -0800432out_ino:
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700433 module_put(de->owner);
Kirill Korotaeve9543652005-10-30 15:02:26 -0800434out_mod:
Kirill Korotaeve9543652005-10-30 15:02:26 -0800435 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436}
437
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700438int proc_fill_super(struct super_block *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439{
440 struct inode * root_inode;
441
Linus Torvalds92d03282006-07-15 12:20:05 -0700442 s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 s->s_blocksize = 1024;
444 s->s_blocksize_bits = 10;
445 s->s_magic = PROC_SUPER_MAGIC;
446 s->s_op = &proc_sops;
447 s->s_time_gran = 1;
448
Alexey Dobriyan76956502007-05-08 00:25:45 -0700449 de_get(&proc_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
451 if (!root_inode)
452 goto out_no_root;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 root_inode->i_uid = 0;
454 root_inode->i_gid = 0;
455 s->s_root = d_alloc_root(root_inode);
456 if (!s->s_root)
457 goto out_no_root;
458 return 0;
459
460out_no_root:
461 printk("proc_read_super: get root inode failed\n");
462 iput(root_inode);
Alexey Dobriyan76956502007-05-08 00:25:45 -0700463 de_put(&proc_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 return -ENOMEM;
465}