2 * proc/fs/generic.c --- generic routines for the proc-fs
4 * This file contains generic proc-fs routines for handling
5 * directories and files.
7 * Copyright (C) 1991, 1992 Linus Torvalds.
8 * Copyright (C) 1997 Theodore Ts'o
11 #include <linux/errno.h>
12 #include <linux/time.h>
13 #include <linux/proc_fs.h>
14 #include <linux/stat.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/printk.h>
19 #include <linux/mount.h>
20 #include <linux/init.h>
21 #include <linux/idr.h>
22 #include <linux/namei.h>
23 #include <linux/bitops.h>
24 #include <linux/spinlock.h>
25 #include <linux/completion.h>
26 #include <asm/uaccess.h>
30 static DEFINE_SPINLOCK(proc_subdir_lock);
32 static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
34 if (de->namelen != len)
36 return !memcmp(name, de->name, len);
39 static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
41 struct inode *inode = dentry->d_inode;
42 struct proc_dir_entry *de = PDE(inode);
45 error = inode_change_ok(inode, iattr);
49 setattr_copy(inode, iattr);
50 mark_inode_dirty(inode);
52 proc_set_user(de, inode->i_uid, inode->i_gid);
53 de->mode = inode->i_mode;
57 static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
60 struct inode *inode = dentry->d_inode;
61 struct proc_dir_entry *de = PROC_I(inode)->pde;
63 set_nlink(inode, de->nlink);
65 generic_fillattr(inode, stat);
69 static const struct inode_operations proc_file_inode_operations = {
70 .setattr = proc_notify_change,
74 * This function parses a name such as "tty/driver/serial", and
75 * returns the struct proc_dir_entry for "/proc/tty/driver", and
76 * returns "serial" in residual.
78 static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
79 const char **residual)
81 const char *cp = name, *next;
82 struct proc_dir_entry *de;
90 next = strchr(cp, '/');
95 for (de = de->subdir; de ; de = de->next) {
96 if (proc_match(len, cp, de))
100 WARN(1, "name '%s'\n", name);
110 static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
111 const char **residual)
115 spin_lock(&proc_subdir_lock);
116 rv = __xlate_proc_name(name, ret, residual);
117 spin_unlock(&proc_subdir_lock);
121 static DEFINE_IDA(proc_inum_ida);
122 static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
124 #define PROC_DYNAMIC_FIRST 0xF0000000U
127 * Return an inode number between PROC_DYNAMIC_FIRST and
128 * 0xffffffff, or zero on failure.
130 int proc_alloc_inum(unsigned int *inum)
136 if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
139 spin_lock_irq(&proc_inum_lock);
140 error = ida_get_new(&proc_inum_ida, &i);
141 spin_unlock_irq(&proc_inum_lock);
142 if (error == -EAGAIN)
147 if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
148 spin_lock_irq(&proc_inum_lock);
149 ida_remove(&proc_inum_ida, i);
150 spin_unlock_irq(&proc_inum_lock);
153 *inum = PROC_DYNAMIC_FIRST + i;
157 void proc_free_inum(unsigned int inum)
160 spin_lock_irqsave(&proc_inum_lock, flags);
161 ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
162 spin_unlock_irqrestore(&proc_inum_lock, flags);
165 static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
167 nd_set_link(nd, __PDE_DATA(dentry->d_inode));
171 static const struct inode_operations proc_link_inode_operations = {
172 .readlink = generic_readlink,
173 .follow_link = proc_follow_link,
177 * Don't create negative dentries here, return -ENOENT by hand
180 struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
181 struct dentry *dentry)
185 spin_lock(&proc_subdir_lock);
186 for (de = de->subdir; de ; de = de->next) {
187 if (de->namelen != dentry->d_name.len)
189 if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
191 spin_unlock(&proc_subdir_lock);
192 inode = proc_get_inode(dir->i_sb, de);
194 return ERR_PTR(-ENOMEM);
195 d_set_d_op(dentry, &simple_dentry_operations);
196 d_add(dentry, inode);
200 spin_unlock(&proc_subdir_lock);
201 return ERR_PTR(-ENOENT);
204 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
207 return proc_lookup_de(PDE(dir), dir, dentry);
211 * This returns non-zero if at EOF, so that the /proc
212 * root directory can use this and check if it should
213 * continue with the <pid> entries..
215 * Note that the VFS-layer doesn't care about the return
216 * value of the readdir() call, as long as it's non-negative
219 int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
220 struct dir_context *ctx)
224 if (!dir_emit_dots(file, ctx))
227 spin_lock(&proc_subdir_lock);
232 spin_unlock(&proc_subdir_lock);
242 struct proc_dir_entry *next;
244 spin_unlock(&proc_subdir_lock);
245 if (!dir_emit(ctx, de->name, de->namelen,
246 de->low_ino, de->mode >> 12)) {
250 spin_lock(&proc_subdir_lock);
256 spin_unlock(&proc_subdir_lock);
260 int proc_readdir(struct file *file, struct dir_context *ctx)
262 struct inode *inode = file_inode(file);
264 return proc_readdir_de(PDE(inode), file, ctx);
268 * These are the generic /proc directory operations. They
269 * use the in-memory "struct proc_dir_entry" tree to parse
270 * the /proc directory.
272 static const struct file_operations proc_dir_operations = {
273 .llseek = generic_file_llseek,
274 .read = generic_read_dir,
275 .iterate = proc_readdir,
279 * proc directories can do almost nothing..
281 static const struct inode_operations proc_dir_inode_operations = {
282 .lookup = proc_lookup,
283 .getattr = proc_getattr,
284 .setattr = proc_notify_change,
287 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
289 struct proc_dir_entry *tmp;
292 ret = proc_alloc_inum(&dp->low_ino);
296 if (S_ISDIR(dp->mode)) {
297 dp->proc_fops = &proc_dir_operations;
298 dp->proc_iops = &proc_dir_inode_operations;
300 } else if (S_ISLNK(dp->mode)) {
301 dp->proc_iops = &proc_link_inode_operations;
302 } else if (S_ISREG(dp->mode)) {
303 BUG_ON(dp->proc_fops == NULL);
304 dp->proc_iops = &proc_file_inode_operations;
310 spin_lock(&proc_subdir_lock);
312 for (tmp = dir->subdir; tmp; tmp = tmp->next)
313 if (strcmp(tmp->name, dp->name) == 0) {
314 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
315 dir->name, dp->name);
319 dp->next = dir->subdir;
322 spin_unlock(&proc_subdir_lock);
327 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
332 struct proc_dir_entry *ent = NULL;
336 if (xlate_proc_name(name, parent, &fn) != 0)
339 qstr.len = strlen(fn);
340 if (qstr.len == 0 || qstr.len >= 256) {
341 WARN(1, "name len %u\n", qstr.len);
344 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
345 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
349 ent = kzalloc(sizeof(struct proc_dir_entry) + qstr.len + 1, GFP_KERNEL);
353 memcpy(ent->name, fn, qstr.len + 1);
354 ent->namelen = qstr.len;
357 atomic_set(&ent->count, 1);
358 spin_lock_init(&ent->pde_unload_lock);
359 INIT_LIST_HEAD(&ent->pde_openers);
364 struct proc_dir_entry *proc_symlink(const char *name,
365 struct proc_dir_entry *parent, const char *dest)
367 struct proc_dir_entry *ent;
369 ent = __proc_create(&parent, name,
370 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
373 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
375 strcpy((char*)ent->data,dest);
376 if (proc_register(parent, ent) < 0) {
388 EXPORT_SYMBOL(proc_symlink);
390 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
391 struct proc_dir_entry *parent, void *data)
393 struct proc_dir_entry *ent;
396 mode = S_IRUGO | S_IXUGO;
398 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
401 if (proc_register(parent, ent) < 0) {
408 EXPORT_SYMBOL_GPL(proc_mkdir_data);
410 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
411 struct proc_dir_entry *parent)
413 return proc_mkdir_data(name, mode, parent, NULL);
415 EXPORT_SYMBOL(proc_mkdir_mode);
417 struct proc_dir_entry *proc_mkdir(const char *name,
418 struct proc_dir_entry *parent)
420 return proc_mkdir_data(name, 0, parent, NULL);
422 EXPORT_SYMBOL(proc_mkdir);
424 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
425 struct proc_dir_entry *parent,
426 const struct file_operations *proc_fops,
429 struct proc_dir_entry *pde;
430 if ((mode & S_IFMT) == 0)
433 if (!S_ISREG(mode)) {
434 WARN_ON(1); /* use proc_mkdir() */
438 if ((mode & S_IALLUGO) == 0)
440 pde = __proc_create(&parent, name, mode, 1);
443 pde->proc_fops = proc_fops;
445 if (proc_register(parent, pde) < 0)
453 EXPORT_SYMBOL(proc_create_data);
455 void proc_set_size(struct proc_dir_entry *de, loff_t size)
459 EXPORT_SYMBOL(proc_set_size);
461 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
466 EXPORT_SYMBOL(proc_set_user);
468 static void free_proc_entry(struct proc_dir_entry *de)
470 proc_free_inum(de->low_ino);
472 if (S_ISLNK(de->mode))
477 void pde_put(struct proc_dir_entry *pde)
479 if (atomic_dec_and_test(&pde->count))
480 free_proc_entry(pde);
484 * Remove a /proc entry and free it if it's not currently in use.
486 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
488 struct proc_dir_entry **p;
489 struct proc_dir_entry *de = NULL;
490 const char *fn = name;
493 spin_lock(&proc_subdir_lock);
494 if (__xlate_proc_name(name, &parent, &fn) != 0) {
495 spin_unlock(&proc_subdir_lock);
500 for (p = &parent->subdir; *p; p=&(*p)->next ) {
501 if (proc_match(len, fn, *p)) {
508 spin_unlock(&proc_subdir_lock);
510 WARN(1, "name '%s'\n", name);
514 proc_entry_rundown(de);
516 if (S_ISDIR(de->mode))
519 WARN(de->subdir, "%s: removing non-empty directory "
520 "'%s/%s', leaking at least '%s'\n", __func__,
521 de->parent->name, de->name, de->subdir->name);
524 EXPORT_SYMBOL(remove_proc_entry);
526 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
528 struct proc_dir_entry **p;
529 struct proc_dir_entry *root = NULL, *de, *next;
530 const char *fn = name;
533 spin_lock(&proc_subdir_lock);
534 if (__xlate_proc_name(name, &parent, &fn) != 0) {
535 spin_unlock(&proc_subdir_lock);
540 for (p = &parent->subdir; *p; p=&(*p)->next ) {
541 if (proc_match(len, fn, *p)) {
549 spin_unlock(&proc_subdir_lock);
556 de->subdir = next->next;
561 spin_unlock(&proc_subdir_lock);
563 proc_entry_rundown(de);
565 if (S_ISDIR(de->mode))
572 spin_lock(&proc_subdir_lock);
578 EXPORT_SYMBOL(remove_proc_subtree);
580 void *proc_get_parent_data(const struct inode *inode)
582 struct proc_dir_entry *de = PDE(inode);
583 return de->parent->data;
585 EXPORT_SYMBOL_GPL(proc_get_parent_data);
587 void proc_remove(struct proc_dir_entry *de)
590 remove_proc_subtree(de->name, de->parent);
592 EXPORT_SYMBOL(proc_remove);
594 void *PDE_DATA(const struct inode *inode)
596 return __PDE_DATA(inode);
598 EXPORT_SYMBOL(PDE_DATA);