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 <linux/uaccess.h>
29 static DEFINE_RWLOCK(proc_subdir_lock);
31 static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
33 if (len < de->namelen)
35 if (len > de->namelen)
38 return memcmp(name, de->name, len);
41 static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
43 return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
47 static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
49 return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
53 static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
57 struct rb_node *node = dir->subdir.rb_node;
60 struct proc_dir_entry *de = rb_entry(node,
61 struct proc_dir_entry,
63 int result = proc_match(len, name, de);
68 node = node->rb_right;
75 static bool pde_subdir_insert(struct proc_dir_entry *dir,
76 struct proc_dir_entry *de)
78 struct rb_root *root = &dir->subdir;
79 struct rb_node **new = &root->rb_node, *parent = NULL;
81 /* Figure out where to put new node */
83 struct proc_dir_entry *this = rb_entry(*new,
84 struct proc_dir_entry,
86 int result = proc_match(de->namelen, de->name, this);
90 new = &(*new)->rb_left;
92 new = &(*new)->rb_right;
97 /* Add new node and rebalance tree. */
98 rb_link_node(&de->subdir_node, parent, new);
99 rb_insert_color(&de->subdir_node, root);
103 static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
105 struct inode *inode = d_inode(dentry);
106 struct proc_dir_entry *de = PDE(inode);
109 error = setattr_prepare(dentry, iattr);
113 setattr_copy(inode, iattr);
114 mark_inode_dirty(inode);
116 proc_set_user(de, inode->i_uid, inode->i_gid);
117 de->mode = inode->i_mode;
121 static int proc_getattr(const struct path *path, struct kstat *stat,
122 u32 request_mask, unsigned int query_flags)
124 struct inode *inode = d_inode(path->dentry);
125 struct proc_dir_entry *de = PDE(inode);
127 set_nlink(inode, de->nlink);
129 generic_fillattr(inode, stat);
133 static const struct inode_operations proc_file_inode_operations = {
134 .setattr = proc_notify_change,
138 * This function parses a name such as "tty/driver/serial", and
139 * returns the struct proc_dir_entry for "/proc/tty/driver", and
140 * returns "serial" in residual.
142 static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
143 const char **residual)
145 const char *cp = name, *next;
146 struct proc_dir_entry *de;
154 next = strchr(cp, '/');
159 de = pde_subdir_find(de, cp, len);
161 WARN(1, "name '%s'\n", name);
171 static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
172 const char **residual)
176 read_lock(&proc_subdir_lock);
177 rv = __xlate_proc_name(name, ret, residual);
178 read_unlock(&proc_subdir_lock);
182 static DEFINE_IDA(proc_inum_ida);
184 #define PROC_DYNAMIC_FIRST 0xF0000000U
187 * Return an inode number between PROC_DYNAMIC_FIRST and
188 * 0xffffffff, or zero on failure.
190 int proc_alloc_inum(unsigned int *inum)
194 i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
199 *inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
203 void proc_free_inum(unsigned int inum)
205 ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
209 * Don't create negative dentries here, return -ENOENT by hand
212 struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
213 struct dentry *dentry)
217 read_lock(&proc_subdir_lock);
218 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
221 read_unlock(&proc_subdir_lock);
222 inode = proc_get_inode(dir->i_sb, de);
224 return ERR_PTR(-ENOMEM);
225 d_set_d_op(dentry, &simple_dentry_operations);
226 d_add(dentry, inode);
229 read_unlock(&proc_subdir_lock);
230 return ERR_PTR(-ENOENT);
233 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
236 return proc_lookup_de(PDE(dir), dir, dentry);
240 * This returns non-zero if at EOF, so that the /proc
241 * root directory can use this and check if it should
242 * continue with the <pid> entries..
244 * Note that the VFS-layer doesn't care about the return
245 * value of the readdir() call, as long as it's non-negative
248 int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
249 struct dir_context *ctx)
253 if (!dir_emit_dots(file, ctx))
256 read_lock(&proc_subdir_lock);
257 de = pde_subdir_first(de);
261 read_unlock(&proc_subdir_lock);
266 de = pde_subdir_next(de);
271 struct proc_dir_entry *next;
273 read_unlock(&proc_subdir_lock);
274 if (!dir_emit(ctx, de->name, de->namelen,
275 de->low_ino, de->mode >> 12)) {
279 read_lock(&proc_subdir_lock);
281 next = pde_subdir_next(de);
285 read_unlock(&proc_subdir_lock);
289 int proc_readdir(struct file *file, struct dir_context *ctx)
291 struct inode *inode = file_inode(file);
293 return proc_readdir_de(PDE(inode), file, ctx);
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 .iterate_shared = 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)
320 ret = proc_alloc_inum(&dp->low_ino);
324 write_lock(&proc_subdir_lock);
326 if (pde_subdir_insert(dir, dp) == false) {
327 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
328 dir->name, dp->name);
329 write_unlock(&proc_subdir_lock);
330 proc_free_inum(dp->low_ino);
333 write_unlock(&proc_subdir_lock);
338 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
343 struct proc_dir_entry *ent = NULL;
347 if (xlate_proc_name(name, parent, &fn) != 0)
350 qstr.len = strlen(fn);
351 if (qstr.len == 0 || qstr.len >= 256) {
352 WARN(1, "name len %u\n", qstr.len);
355 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
356 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
359 if (is_empty_pde(*parent)) {
360 WARN(1, "attempt to add to permanently empty directory");
364 ent = kzalloc(sizeof(struct proc_dir_entry) + qstr.len + 1, GFP_KERNEL);
368 memcpy(ent->name, fn, qstr.len + 1);
369 ent->namelen = qstr.len;
372 ent->subdir = RB_ROOT;
373 atomic_set(&ent->count, 1);
374 spin_lock_init(&ent->pde_unload_lock);
375 INIT_LIST_HEAD(&ent->pde_openers);
376 proc_set_user(ent, (*parent)->uid, (*parent)->gid);
382 struct proc_dir_entry *proc_symlink(const char *name,
383 struct proc_dir_entry *parent, const char *dest)
385 struct proc_dir_entry *ent;
387 ent = __proc_create(&parent, name,
388 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
391 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
393 strcpy((char*)ent->data,dest);
394 ent->proc_iops = &proc_link_inode_operations;
395 if (proc_register(parent, ent) < 0) {
407 EXPORT_SYMBOL(proc_symlink);
409 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
410 struct proc_dir_entry *parent, void *data)
412 struct proc_dir_entry *ent;
415 mode = S_IRUGO | S_IXUGO;
417 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
420 ent->proc_fops = &proc_dir_operations;
421 ent->proc_iops = &proc_dir_inode_operations;
423 if (proc_register(parent, ent) < 0) {
431 EXPORT_SYMBOL_GPL(proc_mkdir_data);
433 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
434 struct proc_dir_entry *parent)
436 return proc_mkdir_data(name, mode, parent, NULL);
438 EXPORT_SYMBOL(proc_mkdir_mode);
440 struct proc_dir_entry *proc_mkdir(const char *name,
441 struct proc_dir_entry *parent)
443 return proc_mkdir_data(name, 0, parent, NULL);
445 EXPORT_SYMBOL(proc_mkdir);
447 struct proc_dir_entry *proc_create_mount_point(const char *name)
449 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
450 struct proc_dir_entry *ent, *parent = NULL;
452 ent = __proc_create(&parent, name, mode, 2);
455 ent->proc_fops = NULL;
456 ent->proc_iops = NULL;
458 if (proc_register(parent, ent) < 0) {
466 EXPORT_SYMBOL(proc_create_mount_point);
468 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
469 struct proc_dir_entry *parent,
470 const struct file_operations *proc_fops,
473 struct proc_dir_entry *pde;
474 if ((mode & S_IFMT) == 0)
477 if (!S_ISREG(mode)) {
478 WARN_ON(1); /* use proc_mkdir() */
482 BUG_ON(proc_fops == NULL);
484 if ((mode & S_IALLUGO) == 0)
486 pde = __proc_create(&parent, name, mode, 1);
489 pde->proc_fops = proc_fops;
491 pde->proc_iops = &proc_file_inode_operations;
492 if (proc_register(parent, pde) < 0)
500 EXPORT_SYMBOL(proc_create_data);
502 void proc_set_size(struct proc_dir_entry *de, loff_t size)
506 EXPORT_SYMBOL(proc_set_size);
508 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
513 EXPORT_SYMBOL(proc_set_user);
515 static void free_proc_entry(struct proc_dir_entry *de)
517 proc_free_inum(de->low_ino);
519 if (S_ISLNK(de->mode))
524 void pde_put(struct proc_dir_entry *pde)
526 if (atomic_dec_and_test(&pde->count))
527 free_proc_entry(pde);
531 * Remove a /proc entry and free it if it's not currently in use.
533 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
535 struct proc_dir_entry *de = NULL;
536 const char *fn = name;
539 write_lock(&proc_subdir_lock);
540 if (__xlate_proc_name(name, &parent, &fn) != 0) {
541 write_unlock(&proc_subdir_lock);
546 de = pde_subdir_find(parent, fn, len);
548 rb_erase(&de->subdir_node, &parent->subdir);
549 write_unlock(&proc_subdir_lock);
551 WARN(1, "name '%s'\n", name);
555 proc_entry_rundown(de);
557 if (S_ISDIR(de->mode))
560 WARN(pde_subdir_first(de),
561 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
562 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
565 EXPORT_SYMBOL(remove_proc_entry);
567 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
569 struct proc_dir_entry *root = NULL, *de, *next;
570 const char *fn = name;
573 write_lock(&proc_subdir_lock);
574 if (__xlate_proc_name(name, &parent, &fn) != 0) {
575 write_unlock(&proc_subdir_lock);
580 root = pde_subdir_find(parent, fn, len);
582 write_unlock(&proc_subdir_lock);
585 rb_erase(&root->subdir_node, &parent->subdir);
589 next = pde_subdir_first(de);
591 rb_erase(&next->subdir_node, &de->subdir);
595 write_unlock(&proc_subdir_lock);
597 proc_entry_rundown(de);
599 if (S_ISDIR(de->mode))
606 write_lock(&proc_subdir_lock);
612 EXPORT_SYMBOL(remove_proc_subtree);
614 void *proc_get_parent_data(const struct inode *inode)
616 struct proc_dir_entry *de = PDE(inode);
617 return de->parent->data;
619 EXPORT_SYMBOL_GPL(proc_get_parent_data);
621 void proc_remove(struct proc_dir_entry *de)
624 remove_proc_subtree(de->name, de->parent);
626 EXPORT_SYMBOL(proc_remove);
628 void *PDE_DATA(const struct inode *inode)
630 return __PDE_DATA(inode);
632 EXPORT_SYMBOL(PDE_DATA);