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/hardirq.h>
12 #include <linux/errno.h>
13 #include <linux/time.h>
14 #include <linux/proc_fs.h>
15 #include <linux/stat.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/printk.h>
20 #include <linux/mount.h>
21 #include <linux/init.h>
22 #include <linux/idr.h>
23 #include <linux/bitops.h>
24 #include <linux/spinlock.h>
25 #include <linux/completion.h>
26 #include <asm/uaccess.h>
30 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 de->uid = inode->i_uid;
53 de->gid = inode->i_gid;
54 de->mode = inode->i_mode;
58 static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
61 struct inode *inode = dentry->d_inode;
62 struct proc_dir_entry *de = PROC_I(inode)->pde;
64 set_nlink(inode, de->nlink);
66 generic_fillattr(inode, stat);
70 static const struct inode_operations proc_file_inode_operations = {
71 .setattr = proc_notify_change,
75 * This function parses a name such as "tty/driver/serial", and
76 * returns the struct proc_dir_entry for "/proc/tty/driver", and
77 * returns "serial" in residual.
79 static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
80 const char **residual)
82 const char *cp = name, *next;
83 struct proc_dir_entry *de;
91 next = strchr(cp, '/');
96 for (de = de->subdir; de ; de = de->next) {
97 if (proc_match(len, cp, de))
101 WARN(1, "name '%s'\n", name);
111 static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
112 const char **residual)
116 spin_lock(&proc_subdir_lock);
117 rv = __xlate_proc_name(name, ret, residual);
118 spin_unlock(&proc_subdir_lock);
122 static DEFINE_IDA(proc_inum_ida);
123 static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
125 #define PROC_DYNAMIC_FIRST 0xF0000000U
128 * Return an inode number between PROC_DYNAMIC_FIRST and
129 * 0xffffffff, or zero on failure.
131 int proc_alloc_inum(unsigned int *inum)
137 if (!ida_pre_get(&proc_inum_ida, (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL))
140 spin_lock_irq(&proc_inum_lock);
141 error = ida_get_new(&proc_inum_ida, &i);
142 spin_unlock_irq(&proc_inum_lock);
143 if (error == -EAGAIN)
148 if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
149 spin_lock_irq(&proc_inum_lock);
150 ida_remove(&proc_inum_ida, i);
151 spin_unlock_irq(&proc_inum_lock);
154 *inum = PROC_DYNAMIC_FIRST + i;
158 void proc_free_inum(unsigned int inum)
161 spin_lock_irqsave(&proc_inum_lock, flags);
162 ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
163 spin_unlock_irqrestore(&proc_inum_lock, flags);
167 * As some entries in /proc are volatile, we want to
168 * get rid of unused dentries. This could be made
169 * smarter: we could keep a "volatile" flag in the
170 * inode to indicate which ones to keep.
172 static int proc_delete_dentry(const struct dentry * dentry)
177 static const struct dentry_operations proc_dentry_operations =
179 .d_delete = proc_delete_dentry,
183 * Don't create negative dentries here, return -ENOENT by hand
186 struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
187 struct dentry *dentry)
191 spin_lock(&proc_subdir_lock);
192 for (de = de->subdir; de ; de = de->next) {
193 if (de->namelen != dentry->d_name.len)
195 if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
197 spin_unlock(&proc_subdir_lock);
198 inode = proc_get_inode(dir->i_sb, de);
200 return ERR_PTR(-ENOMEM);
201 d_set_d_op(dentry, &proc_dentry_operations);
202 d_add(dentry, inode);
206 spin_unlock(&proc_subdir_lock);
207 return ERR_PTR(-ENOENT);
210 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
213 return proc_lookup_de(PDE(dir), dir, dentry);
217 * This returns non-zero if at EOF, so that the /proc
218 * root directory can use this and check if it should
219 * continue with the <pid> entries..
221 * Note that the VFS-layer doesn't care about the return
222 * value of the readdir() call, as long as it's non-negative
225 int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent,
230 struct inode *inode = file_inode(filp);
237 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
243 if (filldir(dirent, "..", 2, i,
244 parent_ino(filp->f_path.dentry),
251 spin_lock(&proc_subdir_lock);
257 spin_unlock(&proc_subdir_lock);
267 struct proc_dir_entry *next;
269 /* filldir passes info to user space */
271 spin_unlock(&proc_subdir_lock);
272 if (filldir(dirent, de->name, de->namelen, filp->f_pos,
273 de->low_ino, de->mode >> 12) < 0) {
277 spin_lock(&proc_subdir_lock);
283 spin_unlock(&proc_subdir_lock);
290 int proc_readdir(struct file *filp, void *dirent, filldir_t filldir)
292 struct inode *inode = file_inode(filp);
294 return proc_readdir_de(PDE(inode), filp, dirent, filldir);
298 * These are the generic /proc directory operations. They
299 * use the in-memory "struct proc_dir_entry" tree to parse
300 * the /proc directory.
302 static const struct file_operations proc_dir_operations = {
303 .llseek = generic_file_llseek,
304 .read = generic_read_dir,
305 .readdir = proc_readdir,
309 * proc directories can do almost nothing..
311 static const struct inode_operations proc_dir_inode_operations = {
312 .lookup = proc_lookup,
313 .getattr = proc_getattr,
314 .setattr = proc_notify_change,
317 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
319 struct proc_dir_entry *tmp;
322 ret = proc_alloc_inum(&dp->low_ino);
326 if (S_ISDIR(dp->mode)) {
327 dp->proc_fops = &proc_dir_operations;
328 dp->proc_iops = &proc_dir_inode_operations;
330 } else if (S_ISLNK(dp->mode)) {
331 dp->proc_iops = &proc_link_inode_operations;
332 } else if (S_ISREG(dp->mode)) {
333 BUG_ON(dp->proc_fops == NULL);
334 dp->proc_iops = &proc_file_inode_operations;
340 spin_lock(&proc_subdir_lock);
342 for (tmp = dir->subdir; tmp; tmp = tmp->next)
343 if (strcmp(tmp->name, dp->name) == 0) {
344 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
345 dir->name, dp->name);
349 dp->next = dir->subdir;
352 spin_unlock(&proc_subdir_lock);
357 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
362 struct proc_dir_entry *ent = NULL;
363 const char *fn = name;
366 /* make sure name is valid */
367 if (!name || !strlen(name))
370 if (xlate_proc_name(name, parent, &fn) != 0)
373 /* At this point there must not be any '/' characters beyond *fn */
379 ent = kzalloc(sizeof(struct proc_dir_entry) + len + 1, (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL);
383 memcpy(ent->name, fn, len + 1);
387 atomic_set(&ent->count, 1);
388 spin_lock_init(&ent->pde_unload_lock);
389 INIT_LIST_HEAD(&ent->pde_openers);
394 struct proc_dir_entry *proc_symlink(const char *name,
395 struct proc_dir_entry *parent, const char *dest)
397 struct proc_dir_entry *ent;
399 ent = __proc_create(&parent, name,
400 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
403 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
405 strcpy((char*)ent->data,dest);
406 if (proc_register(parent, ent) < 0) {
418 EXPORT_SYMBOL(proc_symlink);
420 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
421 struct proc_dir_entry *parent, void *data)
423 struct proc_dir_entry *ent;
426 mode = S_IRUGO | S_IXUGO;
428 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
431 if (proc_register(parent, ent) < 0) {
438 EXPORT_SYMBOL_GPL(proc_mkdir_data);
440 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
441 struct proc_dir_entry *parent)
443 return proc_mkdir_data(name, mode, parent, NULL);
445 EXPORT_SYMBOL(proc_mkdir_mode);
447 struct proc_dir_entry *proc_mkdir(const char *name,
448 struct proc_dir_entry *parent)
450 return proc_mkdir_data(name, 0, parent, NULL);
452 EXPORT_SYMBOL(proc_mkdir);
454 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
455 struct proc_dir_entry *parent,
456 const struct file_operations *proc_fops,
459 struct proc_dir_entry *pde;
460 if ((mode & S_IFMT) == 0)
463 if (!S_ISREG(mode)) {
464 WARN_ON(1); /* use proc_mkdir() */
468 if ((mode & S_IALLUGO) == 0)
470 pde = __proc_create(&parent, name, mode, 1);
473 pde->proc_fops = proc_fops;
475 if (proc_register(parent, pde) < 0)
483 EXPORT_SYMBOL(proc_create_data);
485 void proc_set_size(struct proc_dir_entry *de, loff_t size)
489 EXPORT_SYMBOL(proc_set_size);
491 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
496 EXPORT_SYMBOL(proc_set_user);
498 static void free_proc_entry(struct proc_dir_entry *de)
500 proc_free_inum(de->low_ino);
502 if (S_ISLNK(de->mode))
507 void pde_put(struct proc_dir_entry *pde)
509 if (atomic_dec_and_test(&pde->count))
510 free_proc_entry(pde);
514 * Remove a /proc entry and free it if it's not currently in use.
516 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
518 struct proc_dir_entry **p;
519 struct proc_dir_entry *de = NULL;
520 const char *fn = name;
523 spin_lock(&proc_subdir_lock);
524 if (__xlate_proc_name(name, &parent, &fn) != 0) {
525 spin_unlock(&proc_subdir_lock);
530 for (p = &parent->subdir; *p; p=&(*p)->next ) {
531 if (proc_match(len, fn, *p)) {
538 spin_unlock(&proc_subdir_lock);
540 WARN(1, "name '%s'\n", name);
544 proc_entry_rundown(de);
546 if (S_ISDIR(de->mode))
549 WARN(de->subdir, "%s: removing non-empty directory "
550 "'%s/%s', leaking at least '%s'\n", __func__,
551 de->parent->name, de->name, de->subdir->name);
554 EXPORT_SYMBOL(remove_proc_entry);
556 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
558 struct proc_dir_entry **p;
559 struct proc_dir_entry *root = NULL, *de, *next;
560 const char *fn = name;
563 spin_lock(&proc_subdir_lock);
564 if (__xlate_proc_name(name, &parent, &fn) != 0) {
565 spin_unlock(&proc_subdir_lock);
570 for (p = &parent->subdir; *p; p=&(*p)->next ) {
571 if (proc_match(len, fn, *p)) {
579 spin_unlock(&proc_subdir_lock);
586 de->subdir = next->next;
591 spin_unlock(&proc_subdir_lock);
593 proc_entry_rundown(de);
595 if (S_ISDIR(de->mode))
602 spin_lock(&proc_subdir_lock);
608 EXPORT_SYMBOL(remove_proc_subtree);
610 void *proc_get_parent_data(const struct inode *inode)
612 struct proc_dir_entry *de = PDE(inode);
613 return de->parent->data;
615 EXPORT_SYMBOL_GPL(proc_get_parent_data);
617 void proc_remove(struct proc_dir_entry *de)
620 remove_proc_subtree(de->name, de->parent);
622 EXPORT_SYMBOL(proc_remove);
624 void *PDE_DATA(const struct inode *inode)
626 return __PDE_DATA(inode);
628 EXPORT_SYMBOL(PDE_DATA);