blob: 480cb1065eec8a65d9224075ffc66858dd4d738f [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * proc/fs/generic.c --- generic routines for the proc-fs
3 *
4 * This file contains generic proc-fs routines for handling
5 * directories and files.
6 *
7 * Copyright (C) 1991, 1992 Linus Torvalds.
8 * Copyright (C) 1997 Theodore Ts'o
9 */
10
11#include <linux/errno.h>
12#include <linux/time.h>
13#include <linux/proc_fs.h>
14#include <linux/stat.h>
15#include <linux/module.h>
16#include <linux/mount.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/init.h>
18#include <linux/idr.h>
19#include <linux/namei.h>
20#include <linux/bitops.h>
Steven Rostedt64a07bd2006-03-26 01:36:55 -080021#include <linux/spinlock.h>
Alexey Dobriyan786d7e12007-07-15 23:39:00 -070022#include <linux/completion.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <asm/uaccess.h>
24
Adrian Bunkfee781e2006-01-08 01:04:16 -080025#include "internal.h"
26
Steven Rostedt64a07bd2006-03-26 01:36:55 -080027DEFINE_SPINLOCK(proc_subdir_lock);
28
Eric W. Biederman77b14db2007-02-14 00:34:12 -080029static int proc_match(int len, const char *name, struct proc_dir_entry *de)
Linus Torvalds1da177e2005-04-16 15:20:36 -070030{
31 if (de->namelen != len)
32 return 0;
33 return !memcmp(name, de->name, len);
34}
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036/* buffer size is one page but our output routines use some slack for overruns */
37#define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
38
39static ssize_t
Alexey Dobriyan3dec7f52009-02-20 17:04:33 +030040__proc_file_read(struct file *file, char __user *buf, size_t nbytes,
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 loff_t *ppos)
42{
Josef "Jeff" Sipek2fddfee2006-12-08 02:36:36 -080043 struct inode * inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 char *page;
45 ssize_t retval=0;
46 int eof=0;
47 ssize_t n, count;
48 char *start;
49 struct proc_dir_entry * dp;
Linus Torvalds8b90db02005-12-30 08:39:10 -080050 unsigned long long pos;
51
52 /*
53 * Gaah, please just use "seq_file" instead. The legacy /proc
54 * interfaces cut loff_t down to off_t for reads, and ignore
55 * the offset entirely for writes..
56 */
57 pos = *ppos;
58 if (pos > MAX_NON_LFS)
59 return 0;
60 if (nbytes > MAX_NON_LFS - pos)
61 nbytes = MAX_NON_LFS - pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63 dp = PDE(inode);
Mel Gormane12ba742007-10-16 01:25:52 -070064 if (!(page = (char*) __get_free_page(GFP_TEMPORARY)))
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 return -ENOMEM;
66
67 while ((nbytes > 0) && !eof) {
68 count = min_t(size_t, PROC_BLOCK_SIZE, nbytes);
69
70 start = NULL;
Alexey Dobriyan8731f142008-04-29 01:01:58 -070071 if (dp->read_proc) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 /*
73 * How to be a proc read function
74 * ------------------------------
75 * Prototype:
76 * int f(char *buffer, char **start, off_t offset,
77 * int count, int *peof, void *dat)
78 *
79 * Assume that the buffer is "count" bytes in size.
80 *
81 * If you know you have supplied all the data you
82 * have, set *peof.
83 *
84 * You have three ways to return data:
85 * 0) Leave *start = NULL. (This is the default.)
86 * Put the data of the requested offset at that
87 * offset within the buffer. Return the number (n)
88 * of bytes there are from the beginning of the
89 * buffer up to the last byte of data. If the
90 * number of supplied bytes (= n - offset) is
91 * greater than zero and you didn't signal eof
92 * and the reader is prepared to take more data
93 * you will be called again with the requested
94 * offset advanced by the number of bytes
95 * absorbed. This interface is useful for files
96 * no larger than the buffer.
97 * 1) Set *start = an unsigned long value less than
98 * the buffer address but greater than zero.
99 * Put the data of the requested offset at the
100 * beginning of the buffer. Return the number of
101 * bytes of data placed there. If this number is
102 * greater than zero and you didn't signal eof
103 * and the reader is prepared to take more data
104 * you will be called again with the requested
105 * offset advanced by *start. This interface is
106 * useful when you have a large file consisting
107 * of a series of blocks which you want to count
108 * and return as wholes.
109 * (Hack by Paul.Russell@rustcorp.com.au)
110 * 2) Set *start = an address within the buffer.
111 * Put the data of the requested offset at *start.
112 * Return the number of bytes of data placed there.
113 * If this number is greater than zero and you
114 * didn't signal eof and the reader is prepared to
115 * take more data you will be called again with the
116 * requested offset advanced by the number of bytes
117 * absorbed.
118 */
119 n = dp->read_proc(page, &start, *ppos,
120 count, &eof, dp->data);
121 } else
122 break;
123
124 if (n == 0) /* end of file */
125 break;
126 if (n < 0) { /* error */
127 if (retval == 0)
128 retval = n;
129 break;
130 }
131
132 if (start == NULL) {
133 if (n > PAGE_SIZE) {
134 printk(KERN_ERR
135 "proc_file_read: Apparent buffer overflow!\n");
136 n = PAGE_SIZE;
137 }
138 n -= *ppos;
139 if (n <= 0)
140 break;
141 if (n > count)
142 n = count;
143 start = page + *ppos;
144 } else if (start < page) {
145 if (n > PAGE_SIZE) {
146 printk(KERN_ERR
147 "proc_file_read: Apparent buffer overflow!\n");
148 n = PAGE_SIZE;
149 }
150 if (n > count) {
151 /*
152 * Don't reduce n because doing so might
153 * cut off part of a data block.
154 */
155 printk(KERN_WARNING
156 "proc_file_read: Read count exceeded\n");
157 }
158 } else /* start >= page */ {
159 unsigned long startoff = (unsigned long)(start - page);
160 if (n > (PAGE_SIZE - startoff)) {
161 printk(KERN_ERR
162 "proc_file_read: Apparent buffer overflow!\n");
163 n = PAGE_SIZE - startoff;
164 }
165 if (n > count)
166 n = count;
167 }
168
169 n -= copy_to_user(buf, start < page ? page : start, n);
170 if (n == 0) {
171 if (retval == 0)
172 retval = -EFAULT;
173 break;
174 }
175
176 *ppos += start < page ? (unsigned long)start : n;
177 nbytes -= n;
178 buf += n;
179 retval += n;
180 }
181 free_page((unsigned long) page);
182 return retval;
183}
184
185static ssize_t
Alexey Dobriyan3dec7f52009-02-20 17:04:33 +0300186proc_file_read(struct file *file, char __user *buf, size_t nbytes,
187 loff_t *ppos)
188{
189 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
190 ssize_t rv = -EIO;
191
192 spin_lock(&pde->pde_unload_lock);
193 if (!pde->proc_fops) {
194 spin_unlock(&pde->pde_unload_lock);
195 return rv;
196 }
197 pde->pde_users++;
198 spin_unlock(&pde->pde_unload_lock);
199
200 rv = __proc_file_read(file, buf, nbytes, ppos);
201
202 pde_users_dec(pde);
203 return rv;
204}
205
206static ssize_t
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207proc_file_write(struct file *file, const char __user *buffer,
208 size_t count, loff_t *ppos)
209{
Alexey Dobriyan3dec7f52009-02-20 17:04:33 +0300210 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
211 ssize_t rv = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212
Alexey Dobriyan3dec7f52009-02-20 17:04:33 +0300213 if (pde->write_proc) {
214 spin_lock(&pde->pde_unload_lock);
215 if (!pde->proc_fops) {
216 spin_unlock(&pde->pde_unload_lock);
217 return rv;
218 }
219 pde->pde_users++;
220 spin_unlock(&pde->pde_unload_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
Alexey Dobriyan3dec7f52009-02-20 17:04:33 +0300222 /* FIXME: does this routine need ppos? probably... */
223 rv = pde->write_proc(file, buffer, count, pde->data);
224 pde_users_dec(pde);
225 }
226 return rv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227}
228
229
230static loff_t
231proc_file_lseek(struct file *file, loff_t offset, int orig)
232{
Linus Torvalds8b90db02005-12-30 08:39:10 -0800233 loff_t retval = -EINVAL;
234 switch (orig) {
235 case 1:
236 offset += file->f_pos;
237 /* fallthrough */
238 case 0:
239 if (offset < 0 || offset > MAX_NON_LFS)
240 break;
241 file->f_pos = retval = offset;
242 }
243 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244}
245
Alexey Dobriyan76df0c22008-02-08 04:18:27 -0800246static const struct file_operations proc_file_operations = {
247 .llseek = proc_file_lseek,
248 .read = proc_file_read,
249 .write = proc_file_write,
250};
251
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
253{
254 struct inode *inode = dentry->d_inode;
255 struct proc_dir_entry *de = PDE(inode);
256 int error;
257
258 error = inode_change_ok(inode, iattr);
259 if (error)
260 goto out;
261
262 error = inode_setattr(inode, iattr);
263 if (error)
264 goto out;
265
266 de->uid = inode->i_uid;
267 de->gid = inode->i_gid;
268 de->mode = inode->i_mode;
269out:
270 return error;
271}
272
Miklos Szeredi2b579be2005-09-06 15:17:18 -0700273static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
274 struct kstat *stat)
275{
276 struct inode *inode = dentry->d_inode;
277 struct proc_dir_entry *de = PROC_I(inode)->pde;
278 if (de && de->nlink)
279 inode->i_nlink = de->nlink;
280
281 generic_fillattr(inode, stat);
282 return 0;
283}
284
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800285static const struct inode_operations proc_file_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 .setattr = proc_notify_change,
287};
288
289/*
290 * This function parses a name such as "tty/driver/serial", and
291 * returns the struct proc_dir_entry for "/proc/tty/driver", and
292 * returns "serial" in residual.
293 */
294static int xlate_proc_name(const char *name,
295 struct proc_dir_entry **ret, const char **residual)
296{
297 const char *cp = name, *next;
298 struct proc_dir_entry *de;
299 int len;
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800300 int rtn = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301
Alexey Dobriyan7cee4e02008-04-29 01:01:40 -0700302 de = *ret;
303 if (!de)
304 de = &proc_root;
305
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800306 spin_lock(&proc_subdir_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 while (1) {
308 next = strchr(cp, '/');
309 if (!next)
310 break;
311
312 len = next - cp;
313 for (de = de->subdir; de ; de = de->next) {
314 if (proc_match(len, cp, de))
315 break;
316 }
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800317 if (!de) {
318 rtn = -ENOENT;
319 goto out;
320 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 cp += len + 1;
322 }
323 *residual = cp;
324 *ret = de;
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800325out:
326 spin_unlock(&proc_subdir_lock);
327 return rtn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328}
329
Alexey Dobriyan9a185402008-07-26 11:21:37 +0400330static DEFINE_IDA(proc_inum_ida);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
332
Alexey Dobriyan67935df2008-07-26 11:18:28 +0400333#define PROC_DYNAMIC_FIRST 0xF0000000U
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334
335/*
336 * Return an inode number between PROC_DYNAMIC_FIRST and
337 * 0xffffffff, or zero on failure.
Randy Dunlap1681bc32009-01-13 13:53:48 +0300338 *
339 * Current inode allocations in the proc-fs (hex-numbers):
340 *
341 * 00000000 reserved
342 * 00000001-00000fff static entries (goners)
343 * 001 root-ino
344 *
345 * 00001000-00001fff unused
346 * 0001xxxx-7fffxxxx pid-dir entries for pid 1-7fff
347 * 80000000-efffffff unused
348 * f0000000-ffffffff dynamic entries
349 *
350 * Goal:
351 * Once we split the thing into several virtual filesystems,
352 * we will get rid of magical ranges (and this comment, BTW).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 */
354static unsigned int get_inode_number(void)
355{
Alexey Dobriyan67935df2008-07-26 11:18:28 +0400356 unsigned int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 int error;
358
359retry:
Alexey Dobriyan9a185402008-07-26 11:21:37 +0400360 if (ida_pre_get(&proc_inum_ida, GFP_KERNEL) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 return 0;
362
363 spin_lock(&proc_inum_lock);
Alexey Dobriyan9a185402008-07-26 11:21:37 +0400364 error = ida_get_new(&proc_inum_ida, &i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 spin_unlock(&proc_inum_lock);
366 if (error == -EAGAIN)
367 goto retry;
368 else if (error)
369 return 0;
370
Alexey Dobriyan67935df2008-07-26 11:18:28 +0400371 if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
372 spin_lock(&proc_inum_lock);
Alexey Dobriyan9a185402008-07-26 11:21:37 +0400373 ida_remove(&proc_inum_ida, i);
Alexey Dobriyan67935df2008-07-26 11:18:28 +0400374 spin_unlock(&proc_inum_lock);
Alexey Dobriyancc996092008-08-02 07:30:48 +0400375 return 0;
Alexey Dobriyan67935df2008-07-26 11:18:28 +0400376 }
377 return PROC_DYNAMIC_FIRST + i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378}
379
380static void release_inode_number(unsigned int inum)
381{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 spin_lock(&proc_inum_lock);
Alexey Dobriyan9a185402008-07-26 11:21:37 +0400383 ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 spin_unlock(&proc_inum_lock);
385}
386
Al Viro008b1502005-08-20 00:17:39 +0100387static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388{
389 nd_set_link(nd, PDE(dentry->d_inode)->data);
Al Viro008b1502005-08-20 00:17:39 +0100390 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391}
392
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800393static const struct inode_operations proc_link_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 .readlink = generic_readlink,
395 .follow_link = proc_follow_link,
396};
397
398/*
399 * As some entries in /proc are volatile, we want to
400 * get rid of unused dentries. This could be made
401 * smarter: we could keep a "volatile" flag in the
402 * inode to indicate which ones to keep.
403 */
404static int proc_delete_dentry(struct dentry * dentry)
405{
406 return 1;
407}
408
Al Virod72f71e2009-02-20 05:58:47 +0000409static const struct dentry_operations proc_dentry_operations =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410{
411 .d_delete = proc_delete_dentry,
412};
413
414/*
415 * Don't create negative dentries here, return -ENOENT by hand
416 * instead.
417 */
Pavel Emelyanove9720ac2008-03-07 11:08:40 -0800418struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
419 struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420{
421 struct inode *inode = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 int error = -ENOENT;
423
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800424 spin_lock(&proc_subdir_lock);
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700425 for (de = de->subdir; de ; de = de->next) {
426 if (de->namelen != dentry->d_name.len)
427 continue;
428 if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
429 unsigned int ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700431 ino = de->low_ino;
Alexey Dobriyan135d5652009-12-15 16:45:39 -0800432 pde_get(de);
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700433 spin_unlock(&proc_subdir_lock);
434 error = -EINVAL;
435 inode = proc_get_inode(dir->i_sb, ino, de);
436 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 }
438 }
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800439 spin_unlock(&proc_subdir_lock);
Alexey Dobriyan4237e0d2008-02-08 04:18:27 -0800440out_unlock:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441
442 if (inode) {
443 dentry->d_op = &proc_dentry_operations;
444 d_add(dentry, inode);
445 return NULL;
446 }
Alexey Dobriyan5e971dc2008-04-29 01:01:41 -0700447 if (de)
Alexey Dobriyan135d5652009-12-15 16:45:39 -0800448 pde_put(de);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 return ERR_PTR(error);
450}
451
Pavel Emelyanove9720ac2008-03-07 11:08:40 -0800452struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
453 struct nameidata *nd)
454{
455 return proc_lookup_de(PDE(dir), dir, dentry);
456}
457
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458/*
459 * This returns non-zero if at EOF, so that the /proc
460 * root directory can use this and check if it should
461 * continue with the <pid> entries..
462 *
463 * Note that the VFS-layer doesn't care about the return
464 * value of the readdir() call, as long as it's non-negative
465 * for success..
466 */
Pavel Emelyanove9720ac2008-03-07 11:08:40 -0800467int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent,
468 filldir_t filldir)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 unsigned int ino;
471 int i;
Josef "Jeff" Sipek2fddfee2006-12-08 02:36:36 -0800472 struct inode *inode = filp->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 int ret = 0;
474
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 ino = inode->i_ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 i = filp->f_pos;
477 switch (i) {
478 case 0:
479 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
480 goto out;
481 i++;
482 filp->f_pos++;
483 /* fall through */
484 case 1:
485 if (filldir(dirent, "..", 2, i,
Josef "Jeff" Sipek2fddfee2006-12-08 02:36:36 -0800486 parent_ino(filp->f_path.dentry),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 DT_DIR) < 0)
488 goto out;
489 i++;
490 filp->f_pos++;
491 /* fall through */
492 default:
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800493 spin_lock(&proc_subdir_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 de = de->subdir;
495 i -= 2;
496 for (;;) {
497 if (!de) {
498 ret = 1;
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800499 spin_unlock(&proc_subdir_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 goto out;
501 }
502 if (!i)
503 break;
504 de = de->next;
505 i--;
506 }
507
508 do {
Darrick J. Wong59cd0cb2007-05-08 00:25:47 -0700509 struct proc_dir_entry *next;
510
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800511 /* filldir passes info to user space */
Alexey Dobriyan135d5652009-12-15 16:45:39 -0800512 pde_get(de);
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800513 spin_unlock(&proc_subdir_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 if (filldir(dirent, de->name, de->namelen, filp->f_pos,
Darrick J. Wong59cd0cb2007-05-08 00:25:47 -0700515 de->low_ino, de->mode >> 12) < 0) {
Alexey Dobriyan135d5652009-12-15 16:45:39 -0800516 pde_put(de);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 goto out;
Darrick J. Wong59cd0cb2007-05-08 00:25:47 -0700518 }
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800519 spin_lock(&proc_subdir_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 filp->f_pos++;
Darrick J. Wong59cd0cb2007-05-08 00:25:47 -0700521 next = de->next;
Alexey Dobriyan135d5652009-12-15 16:45:39 -0800522 pde_put(de);
Darrick J. Wong59cd0cb2007-05-08 00:25:47 -0700523 de = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 } while (de);
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800525 spin_unlock(&proc_subdir_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 }
527 ret = 1;
Alexey Dobriyanb4df2b92008-10-27 22:48:36 +0300528out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 return ret;
530}
531
Pavel Emelyanove9720ac2008-03-07 11:08:40 -0800532int proc_readdir(struct file *filp, void *dirent, filldir_t filldir)
533{
534 struct inode *inode = filp->f_path.dentry->d_inode;
535
536 return proc_readdir_de(PDE(inode), filp, dirent, filldir);
537}
538
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539/*
540 * These are the generic /proc directory operations. They
541 * use the in-memory "struct proc_dir_entry" tree to parse
542 * the /proc directory.
543 */
Arjan van de Ven00977a52007-02-12 00:55:34 -0800544static const struct file_operations proc_dir_operations = {
Alexey Dobriyanb4df2b92008-10-27 22:48:36 +0300545 .llseek = generic_file_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 .read = generic_read_dir,
547 .readdir = proc_readdir,
548};
549
550/*
551 * proc directories can do almost nothing..
552 */
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800553static const struct inode_operations proc_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 .lookup = proc_lookup,
Miklos Szeredi2b579be2005-09-06 15:17:18 -0700555 .getattr = proc_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 .setattr = proc_notify_change,
557};
558
559static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
560{
561 unsigned int i;
Zhang Rui94413d82008-02-08 04:18:29 -0800562 struct proc_dir_entry *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563
564 i = get_inode_number();
565 if (i == 0)
566 return -EAGAIN;
567 dp->low_ino = i;
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800568
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 if (S_ISDIR(dp->mode)) {
570 if (dp->proc_iops == NULL) {
571 dp->proc_fops = &proc_dir_operations;
572 dp->proc_iops = &proc_dir_inode_operations;
573 }
574 dir->nlink++;
575 } else if (S_ISLNK(dp->mode)) {
576 if (dp->proc_iops == NULL)
577 dp->proc_iops = &proc_link_inode_operations;
578 } else if (S_ISREG(dp->mode)) {
579 if (dp->proc_fops == NULL)
580 dp->proc_fops = &proc_file_operations;
581 if (dp->proc_iops == NULL)
582 dp->proc_iops = &proc_file_inode_operations;
583 }
Changli Gao99fc06d2007-07-15 23:40:09 -0700584
585 spin_lock(&proc_subdir_lock);
Zhang Rui94413d82008-02-08 04:18:29 -0800586
587 for (tmp = dir->subdir; tmp; tmp = tmp->next)
588 if (strcmp(tmp->name, dp->name) == 0) {
Arjan van de Ven6c2f91e2008-09-13 19:51:30 -0700589 WARN(1, KERN_WARNING "proc_dir_entry '%s/%s' already registered\n",
Alexey Dobriyan665020c2008-09-13 02:33:06 -0700590 dir->name, dp->name);
Zhang Rui94413d82008-02-08 04:18:29 -0800591 break;
592 }
593
Changli Gao99fc06d2007-07-15 23:40:09 -0700594 dp->next = dir->subdir;
595 dp->parent = dir;
596 dir->subdir = dp;
597 spin_unlock(&proc_subdir_lock);
598
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 return 0;
600}
601
Alexey Dobriyan2d3a4e32008-02-08 04:18:37 -0800602static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 const char *name,
604 mode_t mode,
605 nlink_t nlink)
606{
607 struct proc_dir_entry *ent = NULL;
608 const char *fn = name;
609 int len;
610
611 /* make sure name is valid */
612 if (!name || !strlen(name)) goto out;
613
Alexey Dobriyan7cee4e02008-04-29 01:01:40 -0700614 if (xlate_proc_name(name, parent, &fn) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 goto out;
616
617 /* At this point there must not be any '/' characters beyond *fn */
618 if (strchr(fn, '/'))
619 goto out;
620
621 len = strlen(fn);
622
623 ent = kmalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
624 if (!ent) goto out;
625
626 memset(ent, 0, sizeof(struct proc_dir_entry));
627 memcpy(((char *) ent) + sizeof(struct proc_dir_entry), fn, len + 1);
628 ent->name = ((char *) ent) + sizeof(*ent);
629 ent->namelen = len;
630 ent->mode = mode;
631 ent->nlink = nlink;
Alexey Dobriyan5a622f22007-12-04 23:45:28 -0800632 atomic_set(&ent->count, 1);
Alexey Dobriyan786d7e12007-07-15 23:39:00 -0700633 ent->pde_users = 0;
634 spin_lock_init(&ent->pde_unload_lock);
635 ent->pde_unload_completion = NULL;
Alexey Dobriyan881adb82008-07-25 01:48:29 -0700636 INIT_LIST_HEAD(&ent->pde_openers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 out:
638 return ent;
639}
640
641struct proc_dir_entry *proc_symlink(const char *name,
642 struct proc_dir_entry *parent, const char *dest)
643{
644 struct proc_dir_entry *ent;
645
Alexey Dobriyan2d3a4e32008-02-08 04:18:37 -0800646 ent = __proc_create(&parent, name,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
648
649 if (ent) {
650 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
651 if (ent->data) {
652 strcpy((char*)ent->data,dest);
653 if (proc_register(parent, ent) < 0) {
654 kfree(ent->data);
655 kfree(ent);
656 ent = NULL;
657 }
658 } else {
659 kfree(ent);
660 ent = NULL;
661 }
662 }
663 return ent;
664}
665
666struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
667 struct proc_dir_entry *parent)
668{
669 struct proc_dir_entry *ent;
670
Alexey Dobriyan2d3a4e32008-02-08 04:18:37 -0800671 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 if (ent) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 if (proc_register(parent, ent) < 0) {
674 kfree(ent);
675 ent = NULL;
676 }
677 }
678 return ent;
679}
680
Denis V. Lunev78e92b92008-05-02 04:12:41 -0700681struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name,
682 struct proc_dir_entry *parent)
683{
684 struct proc_dir_entry *ent;
685
686 ent = __proc_create(&parent, name, S_IFDIR | S_IRUGO | S_IXUGO, 2);
687 if (ent) {
688 ent->data = net;
689 if (proc_register(parent, ent) < 0) {
690 kfree(ent);
691 ent = NULL;
692 }
693 }
694 return ent;
695}
696EXPORT_SYMBOL_GPL(proc_net_mkdir);
697
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698struct proc_dir_entry *proc_mkdir(const char *name,
699 struct proc_dir_entry *parent)
700{
701 return proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
702}
703
704struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
705 struct proc_dir_entry *parent)
706{
707 struct proc_dir_entry *ent;
708 nlink_t nlink;
709
710 if (S_ISDIR(mode)) {
711 if ((mode & S_IALLUGO) == 0)
712 mode |= S_IRUGO | S_IXUGO;
713 nlink = 2;
714 } else {
715 if ((mode & S_IFMT) == 0)
716 mode |= S_IFREG;
717 if ((mode & S_IALLUGO) == 0)
718 mode |= S_IRUGO;
719 nlink = 1;
720 }
721
Alexey Dobriyan2d3a4e32008-02-08 04:18:37 -0800722 ent = __proc_create(&parent, name, mode, nlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 if (ent) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 if (proc_register(parent, ent) < 0) {
725 kfree(ent);
726 ent = NULL;
727 }
728 }
729 return ent;
730}
731
Denis V. Lunev59b74352008-04-29 01:02:00 -0700732struct proc_dir_entry *proc_create_data(const char *name, mode_t mode,
733 struct proc_dir_entry *parent,
734 const struct file_operations *proc_fops,
735 void *data)
Alexey Dobriyan2d3a4e32008-02-08 04:18:37 -0800736{
737 struct proc_dir_entry *pde;
738 nlink_t nlink;
739
740 if (S_ISDIR(mode)) {
741 if ((mode & S_IALLUGO) == 0)
742 mode |= S_IRUGO | S_IXUGO;
743 nlink = 2;
744 } else {
745 if ((mode & S_IFMT) == 0)
746 mode |= S_IFREG;
747 if ((mode & S_IALLUGO) == 0)
748 mode |= S_IRUGO;
749 nlink = 1;
750 }
751
752 pde = __proc_create(&parent, name, mode, nlink);
753 if (!pde)
754 goto out;
755 pde->proc_fops = proc_fops;
Denis V. Lunev59b74352008-04-29 01:02:00 -0700756 pde->data = data;
Alexey Dobriyan2d3a4e32008-02-08 04:18:37 -0800757 if (proc_register(parent, pde) < 0)
758 goto out_free;
759 return pde;
760out_free:
761 kfree(pde);
762out:
763 return NULL;
764}
765
Alexey Dobriyan135d5652009-12-15 16:45:39 -0800766static void free_proc_entry(struct proc_dir_entry *de)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767{
768 unsigned int ino = de->low_ino;
769
770 if (ino < PROC_DYNAMIC_FIRST)
771 return;
772
773 release_inode_number(ino);
774
Alexey Dobriyanfd2cbe42008-02-08 04:18:28 -0800775 if (S_ISLNK(de->mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 kfree(de->data);
777 kfree(de);
778}
779
Alexey Dobriyan135d5652009-12-15 16:45:39 -0800780void pde_put(struct proc_dir_entry *pde)
781{
782 if (atomic_dec_and_test(&pde->count))
783 free_proc_entry(pde);
784}
785
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786/*
787 * Remove a /proc entry and free it if it's not currently in use.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 */
789void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
790{
791 struct proc_dir_entry **p;
Alexey Dobriyanf649d6d2008-04-29 01:01:39 -0700792 struct proc_dir_entry *de = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 const char *fn = name;
794 int len;
795
Alexey Dobriyan7cee4e02008-04-29 01:01:40 -0700796 if (xlate_proc_name(name, &parent, &fn) != 0)
Alexey Dobriyanf649d6d2008-04-29 01:01:39 -0700797 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 len = strlen(fn);
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800799
800 spin_lock(&proc_subdir_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 for (p = &parent->subdir; *p; p=&(*p)->next ) {
Alexey Dobriyanf649d6d2008-04-29 01:01:39 -0700802 if (proc_match(len, fn, *p)) {
803 de = *p;
804 *p = de->next;
805 de->next = NULL;
806 break;
Alexey Dobriyan786d7e12007-07-15 23:39:00 -0700807 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 }
Steven Rostedt64a07bd2006-03-26 01:36:55 -0800809 spin_unlock(&proc_subdir_lock);
Alexey Dobriyanf649d6d2008-04-29 01:01:39 -0700810 if (!de)
811 return;
812
813 spin_lock(&de->pde_unload_lock);
814 /*
815 * Stop accepting new callers into module. If you're
816 * dynamically allocating ->proc_fops, save a pointer somewhere.
817 */
818 de->proc_fops = NULL;
819 /* Wait until all existing callers into module are done. */
820 if (de->pde_users > 0) {
821 DECLARE_COMPLETION_ONSTACK(c);
822
823 if (!de->pde_unload_completion)
824 de->pde_unload_completion = &c;
825
826 spin_unlock(&de->pde_unload_lock);
827
828 wait_for_completion(de->pde_unload_completion);
829
830 goto continue_removing;
831 }
832 spin_unlock(&de->pde_unload_lock);
833
834continue_removing:
Alexey Dobriyan881adb82008-07-25 01:48:29 -0700835 spin_lock(&de->pde_unload_lock);
836 while (!list_empty(&de->pde_openers)) {
837 struct pde_opener *pdeo;
838
839 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
840 list_del(&pdeo->lh);
841 spin_unlock(&de->pde_unload_lock);
842 pdeo->release(pdeo->inode, pdeo->file);
843 kfree(pdeo);
844 spin_lock(&de->pde_unload_lock);
845 }
846 spin_unlock(&de->pde_unload_lock);
847
Alexey Dobriyanf649d6d2008-04-29 01:01:39 -0700848 if (S_ISDIR(de->mode))
849 parent->nlink--;
850 de->nlink = 0;
Arjan van de Ven267e2a92008-07-25 19:45:41 -0700851 WARN(de->subdir, KERN_WARNING "%s: removing non-empty directory "
Alexey Dobriyanf649d6d2008-04-29 01:01:39 -0700852 "'%s/%s', leaking at least '%s'\n", __func__,
853 de->parent->name, de->name, de->subdir->name);
Alexey Dobriyan135d5652009-12-15 16:45:39 -0800854 pde_put(de);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855}