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 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, 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);
166 static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
168 nd_set_link(nd, __PDE_DATA(dentry->d_inode));
172 static const struct inode_operations proc_link_inode_operations = {
173 .readlink = generic_readlink,
174 .follow_link = proc_follow_link,
178 * Don't create negative dentries here, return -ENOENT by hand
181 struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
182 struct dentry *dentry)
186 spin_lock(&proc_subdir_lock);
187 for (de = de->subdir; de ; de = de->next) {
188 if (de->namelen != dentry->d_name.len)
190 if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
192 spin_unlock(&proc_subdir_lock);
193 inode = proc_get_inode(dir->i_sb, de);
195 return ERR_PTR(-ENOMEM);
196 d_set_d_op(dentry, &simple_dentry_operations);
197 d_add(dentry, inode);
201 spin_unlock(&proc_subdir_lock);
202 return ERR_PTR(-ENOENT);
205 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
208 return proc_lookup_de(PDE(dir), dir, dentry);
212 * This returns non-zero if at EOF, so that the /proc
213 * root directory can use this and check if it should
214 * continue with the <pid> entries..
216 * Note that the VFS-layer doesn't care about the return
217 * value of the readdir() call, as long as it's non-negative
220 int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
221 struct dir_context *ctx)
225 if (!dir_emit_dots(file, ctx))
228 spin_lock(&proc_subdir_lock);
233 spin_unlock(&proc_subdir_lock);
243 struct proc_dir_entry *next;
245 spin_unlock(&proc_subdir_lock);
246 if (!dir_emit(ctx, de->name, de->namelen,
247 de->low_ino, de->mode >> 12)) {
251 spin_lock(&proc_subdir_lock);
257 spin_unlock(&proc_subdir_lock);
261 int proc_readdir(struct file *file, struct dir_context *ctx)
263 struct inode *inode = file_inode(file);
265 return proc_readdir_de(PDE(inode), file, ctx);
269 * These are the generic /proc directory operations. They
270 * use the in-memory "struct proc_dir_entry" tree to parse
271 * the /proc directory.
273 static const struct file_operations proc_dir_operations = {
274 .llseek = generic_file_llseek,
275 .read = generic_read_dir,
276 .iterate = proc_readdir,
280 * proc directories can do almost nothing..
282 static const struct inode_operations proc_dir_inode_operations = {
283 .lookup = proc_lookup,
284 .getattr = proc_getattr,
285 .setattr = proc_notify_change,
288 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
290 struct proc_dir_entry *tmp;
293 ret = proc_alloc_inum(&dp->low_ino);
297 if (S_ISDIR(dp->mode)) {
298 dp->proc_fops = &proc_dir_operations;
299 dp->proc_iops = &proc_dir_inode_operations;
301 } else if (S_ISLNK(dp->mode)) {
302 dp->proc_iops = &proc_link_inode_operations;
303 } else if (S_ISREG(dp->mode)) {
304 BUG_ON(dp->proc_fops == NULL);
305 dp->proc_iops = &proc_file_inode_operations;
311 spin_lock(&proc_subdir_lock);
313 for (tmp = dir->subdir; tmp; tmp = tmp->next)
314 if (strcmp(tmp->name, dp->name) == 0) {
315 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
316 dir->name, dp->name);
320 dp->next = dir->subdir;
323 spin_unlock(&proc_subdir_lock);
328 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
333 struct proc_dir_entry *ent = NULL;
334 const char *fn = name;
337 /* make sure name is valid */
338 if (!name || !strlen(name))
341 if (xlate_proc_name(name, parent, &fn) != 0)
344 /* At this point there must not be any '/' characters beyond *fn */
350 ent = kzalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
354 memcpy(ent->name, fn, len + 1);
358 atomic_set(&ent->count, 1);
359 spin_lock_init(&ent->pde_unload_lock);
360 INIT_LIST_HEAD(&ent->pde_openers);
365 struct proc_dir_entry *proc_symlink(const char *name,
366 struct proc_dir_entry *parent, const char *dest)
368 struct proc_dir_entry *ent;
370 ent = __proc_create(&parent, name,
371 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
374 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
376 strcpy((char*)ent->data,dest);
377 if (proc_register(parent, ent) < 0) {
389 EXPORT_SYMBOL(proc_symlink);
391 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
392 struct proc_dir_entry *parent, void *data)
394 struct proc_dir_entry *ent;
397 mode = S_IRUGO | S_IXUGO;
399 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
402 if (proc_register(parent, ent) < 0) {
409 EXPORT_SYMBOL_GPL(proc_mkdir_data);
411 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
412 struct proc_dir_entry *parent)
414 return proc_mkdir_data(name, mode, parent, NULL);
416 EXPORT_SYMBOL(proc_mkdir_mode);
418 struct proc_dir_entry *proc_mkdir(const char *name,
419 struct proc_dir_entry *parent)
421 return proc_mkdir_data(name, 0, parent, NULL);
423 EXPORT_SYMBOL(proc_mkdir);
425 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
426 struct proc_dir_entry *parent,
427 const struct file_operations *proc_fops,
430 struct proc_dir_entry *pde;
431 if ((mode & S_IFMT) == 0)
434 if (!S_ISREG(mode)) {
435 WARN_ON(1); /* use proc_mkdir() */
439 if ((mode & S_IALLUGO) == 0)
441 pde = __proc_create(&parent, name, mode, 1);
444 pde->proc_fops = proc_fops;
446 if (proc_register(parent, pde) < 0)
454 EXPORT_SYMBOL(proc_create_data);
456 void proc_set_size(struct proc_dir_entry *de, loff_t size)
460 EXPORT_SYMBOL(proc_set_size);
462 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
467 EXPORT_SYMBOL(proc_set_user);
469 static void free_proc_entry(struct proc_dir_entry *de)
471 proc_free_inum(de->low_ino);
473 if (S_ISLNK(de->mode))
478 void pde_put(struct proc_dir_entry *pde)
480 if (atomic_dec_and_test(&pde->count))
481 free_proc_entry(pde);
485 * Remove a /proc entry and free it if it's not currently in use.
487 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
489 struct proc_dir_entry **p;
490 struct proc_dir_entry *de = NULL;
491 const char *fn = name;
494 spin_lock(&proc_subdir_lock);
495 if (__xlate_proc_name(name, &parent, &fn) != 0) {
496 spin_unlock(&proc_subdir_lock);
501 for (p = &parent->subdir; *p; p=&(*p)->next ) {
502 if (proc_match(len, fn, *p)) {
509 spin_unlock(&proc_subdir_lock);
511 WARN(1, "name '%s'\n", name);
515 proc_entry_rundown(de);
517 if (S_ISDIR(de->mode))
520 WARN(de->subdir, "%s: removing non-empty directory "
521 "'%s/%s', leaking at least '%s'\n", __func__,
522 de->parent->name, de->name, de->subdir->name);
525 EXPORT_SYMBOL(remove_proc_entry);
527 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
529 struct proc_dir_entry **p;
530 struct proc_dir_entry *root = NULL, *de, *next;
531 const char *fn = name;
534 spin_lock(&proc_subdir_lock);
535 if (__xlate_proc_name(name, &parent, &fn) != 0) {
536 spin_unlock(&proc_subdir_lock);
541 for (p = &parent->subdir; *p; p=&(*p)->next ) {
542 if (proc_match(len, fn, *p)) {
550 spin_unlock(&proc_subdir_lock);
557 de->subdir = next->next;
562 spin_unlock(&proc_subdir_lock);
564 proc_entry_rundown(de);
566 if (S_ISDIR(de->mode))
573 spin_lock(&proc_subdir_lock);
579 EXPORT_SYMBOL(remove_proc_subtree);
581 void *proc_get_parent_data(const struct inode *inode)
583 struct proc_dir_entry *de = PDE(inode);
584 return de->parent->data;
586 EXPORT_SYMBOL_GPL(proc_get_parent_data);
588 void proc_remove(struct proc_dir_entry *de)
591 remove_proc_subtree(de->name, de->parent);
593 EXPORT_SYMBOL(proc_remove);
595 void *PDE_DATA(const struct inode *inode)
597 return __PDE_DATA(inode);
599 EXPORT_SYMBOL(PDE_DATA);