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/bitops.h>
23 #include <linux/spinlock.h>
24 #include <linux/completion.h>
25 #include <asm/uaccess.h>
29 DEFINE_SPINLOCK(proc_subdir_lock);
31 static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
33 if (de->namelen != len)
35 return !memcmp(name, de->name, len);
38 static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
40 struct inode *inode = dentry->d_inode;
41 struct proc_dir_entry *de = PDE(inode);
44 error = inode_change_ok(inode, iattr);
48 setattr_copy(inode, iattr);
49 mark_inode_dirty(inode);
51 de->uid = inode->i_uid;
52 de->gid = 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);
166 * As some entries in /proc are volatile, we want to
167 * get rid of unused dentries. This could be made
168 * smarter: we could keep a "volatile" flag in the
169 * inode to indicate which ones to keep.
171 static int proc_delete_dentry(const struct dentry * dentry)
176 static const struct dentry_operations proc_dentry_operations =
178 .d_delete = proc_delete_dentry,
182 * Don't create negative dentries here, return -ENOENT by hand
185 struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
186 struct dentry *dentry)
190 spin_lock(&proc_subdir_lock);
191 for (de = de->subdir; de ; de = de->next) {
192 if (de->namelen != dentry->d_name.len)
194 if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
196 spin_unlock(&proc_subdir_lock);
197 inode = proc_get_inode(dir->i_sb, de);
199 return ERR_PTR(-ENOMEM);
200 d_set_d_op(dentry, &proc_dentry_operations);
201 d_add(dentry, inode);
205 spin_unlock(&proc_subdir_lock);
206 return ERR_PTR(-ENOENT);
209 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
212 return proc_lookup_de(PDE(dir), dir, dentry);
216 * This returns non-zero if at EOF, so that the /proc
217 * root directory can use this and check if it should
218 * continue with the <pid> entries..
220 * Note that the VFS-layer doesn't care about the return
221 * value of the readdir() call, as long as it's non-negative
224 int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent,
229 struct inode *inode = file_inode(filp);
236 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
242 if (filldir(dirent, "..", 2, i,
243 parent_ino(filp->f_path.dentry),
250 spin_lock(&proc_subdir_lock);
256 spin_unlock(&proc_subdir_lock);
266 struct proc_dir_entry *next;
268 /* filldir passes info to user space */
270 spin_unlock(&proc_subdir_lock);
271 if (filldir(dirent, de->name, de->namelen, filp->f_pos,
272 de->low_ino, de->mode >> 12) < 0) {
276 spin_lock(&proc_subdir_lock);
282 spin_unlock(&proc_subdir_lock);
289 int proc_readdir(struct file *filp, void *dirent, filldir_t filldir)
291 struct inode *inode = file_inode(filp);
293 return proc_readdir_de(PDE(inode), filp, dirent, filldir);
297 * These are the generic /proc directory operations. They
298 * use the in-memory "struct proc_dir_entry" tree to parse
299 * the /proc directory.
301 static const struct file_operations proc_dir_operations = {
302 .llseek = generic_file_llseek,
303 .read = generic_read_dir,
304 .readdir = proc_readdir,
308 * proc directories can do almost nothing..
310 static const struct inode_operations proc_dir_inode_operations = {
311 .lookup = proc_lookup,
312 .getattr = proc_getattr,
313 .setattr = proc_notify_change,
316 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
318 struct proc_dir_entry *tmp;
321 ret = proc_alloc_inum(&dp->low_ino);
325 if (S_ISDIR(dp->mode)) {
326 dp->proc_fops = &proc_dir_operations;
327 dp->proc_iops = &proc_dir_inode_operations;
329 } else if (S_ISLNK(dp->mode)) {
330 dp->proc_iops = &proc_link_inode_operations;
331 } else if (S_ISREG(dp->mode)) {
332 BUG_ON(dp->proc_fops == NULL);
333 dp->proc_iops = &proc_file_inode_operations;
339 spin_lock(&proc_subdir_lock);
341 for (tmp = dir->subdir; tmp; tmp = tmp->next)
342 if (strcmp(tmp->name, dp->name) == 0) {
343 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
344 dir->name, dp->name);
348 dp->next = dir->subdir;
351 spin_unlock(&proc_subdir_lock);
356 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
361 struct proc_dir_entry *ent = NULL;
362 const char *fn = name;
365 /* make sure name is valid */
366 if (!name || !strlen(name))
369 if (xlate_proc_name(name, parent, &fn) != 0)
372 /* At this point there must not be any '/' characters beyond *fn */
378 ent = kzalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
382 memcpy(ent->name, fn, len + 1);
386 atomic_set(&ent->count, 1);
387 spin_lock_init(&ent->pde_unload_lock);
388 INIT_LIST_HEAD(&ent->pde_openers);
393 struct proc_dir_entry *proc_symlink(const char *name,
394 struct proc_dir_entry *parent, const char *dest)
396 struct proc_dir_entry *ent;
398 ent = __proc_create(&parent, name,
399 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
402 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
404 strcpy((char*)ent->data,dest);
405 if (proc_register(parent, ent) < 0) {
417 EXPORT_SYMBOL(proc_symlink);
419 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
420 struct proc_dir_entry *parent, void *data)
422 struct proc_dir_entry *ent;
425 mode = S_IRUGO | S_IXUGO;
427 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
430 if (proc_register(parent, ent) < 0) {
437 EXPORT_SYMBOL_GPL(proc_mkdir_data);
439 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
440 struct proc_dir_entry *parent)
442 return proc_mkdir_data(name, mode, parent, NULL);
444 EXPORT_SYMBOL(proc_mkdir_mode);
446 struct proc_dir_entry *proc_mkdir(const char *name,
447 struct proc_dir_entry *parent)
449 return proc_mkdir_data(name, 0, parent, NULL);
451 EXPORT_SYMBOL(proc_mkdir);
453 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
454 struct proc_dir_entry *parent,
455 const struct file_operations *proc_fops,
458 struct proc_dir_entry *pde;
459 if ((mode & S_IFMT) == 0)
462 if (!S_ISREG(mode)) {
463 WARN_ON(1); /* use proc_mkdir() */
467 if ((mode & S_IALLUGO) == 0)
469 pde = __proc_create(&parent, name, mode, 1);
472 pde->proc_fops = proc_fops;
474 if (proc_register(parent, pde) < 0)
482 EXPORT_SYMBOL(proc_create_data);
484 void proc_set_size(struct proc_dir_entry *de, loff_t size)
488 EXPORT_SYMBOL(proc_set_size);
490 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
495 EXPORT_SYMBOL(proc_set_user);
497 static void free_proc_entry(struct proc_dir_entry *de)
499 proc_free_inum(de->low_ino);
501 if (S_ISLNK(de->mode))
506 void pde_put(struct proc_dir_entry *pde)
508 if (atomic_dec_and_test(&pde->count))
509 free_proc_entry(pde);
513 * Remove a /proc entry and free it if it's not currently in use.
515 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
517 struct proc_dir_entry **p;
518 struct proc_dir_entry *de = NULL;
519 const char *fn = name;
522 spin_lock(&proc_subdir_lock);
523 if (__xlate_proc_name(name, &parent, &fn) != 0) {
524 spin_unlock(&proc_subdir_lock);
529 for (p = &parent->subdir; *p; p=&(*p)->next ) {
530 if (proc_match(len, fn, *p)) {
537 spin_unlock(&proc_subdir_lock);
539 WARN(1, "name '%s'\n", name);
543 proc_entry_rundown(de);
545 if (S_ISDIR(de->mode))
548 WARN(de->subdir, "%s: removing non-empty directory "
549 "'%s/%s', leaking at least '%s'\n", __func__,
550 de->parent->name, de->name, de->subdir->name);
553 EXPORT_SYMBOL(remove_proc_entry);
555 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
557 struct proc_dir_entry **p;
558 struct proc_dir_entry *root = NULL, *de, *next;
559 const char *fn = name;
562 spin_lock(&proc_subdir_lock);
563 if (__xlate_proc_name(name, &parent, &fn) != 0) {
564 spin_unlock(&proc_subdir_lock);
569 for (p = &parent->subdir; *p; p=&(*p)->next ) {
570 if (proc_match(len, fn, *p)) {
578 spin_unlock(&proc_subdir_lock);
585 de->subdir = next->next;
590 spin_unlock(&proc_subdir_lock);
592 proc_entry_rundown(de);
594 if (S_ISDIR(de->mode))
601 spin_lock(&proc_subdir_lock);
607 EXPORT_SYMBOL(remove_proc_subtree);
609 void *proc_get_parent_data(const struct inode *inode)
611 struct proc_dir_entry *de = PDE(inode);
612 return de->parent->data;
614 EXPORT_SYMBOL_GPL(proc_get_parent_data);
616 void proc_remove(struct proc_dir_entry *de)
619 remove_proc_subtree(de->name, de->parent);
621 EXPORT_SYMBOL(proc_remove);
623 void *PDE_DATA(const struct inode *inode)
625 return __PDE_DATA(inode);
627 EXPORT_SYMBOL(PDE_DATA);