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_cached(&dir->subdir),
44 struct proc_dir_entry, subdir_node);
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_root.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_cached *root = &dir->subdir;
79 struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
82 /* Figure out where to put new node */
84 struct proc_dir_entry *this = rb_entry(*new,
85 struct proc_dir_entry,
87 int result = proc_match(de->namelen, de->name, this);
91 new = &(*new)->rb_left;
92 else if (result > 0) {
93 new = &(*new)->rb_right;
99 /* Add new node and rebalance tree. */
100 rb_link_node(&de->subdir_node, parent, new);
101 rb_insert_color_cached(&de->subdir_node, root, leftmost);
105 static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
107 struct inode *inode = d_inode(dentry);
108 struct proc_dir_entry *de = PDE(inode);
111 error = setattr_prepare(dentry, iattr);
115 setattr_copy(inode, iattr);
116 mark_inode_dirty(inode);
118 proc_set_user(de, inode->i_uid, inode->i_gid);
119 de->mode = inode->i_mode;
123 static int proc_getattr(const struct path *path, struct kstat *stat,
124 u32 request_mask, unsigned int query_flags)
126 struct inode *inode = d_inode(path->dentry);
127 struct proc_dir_entry *de = PDE(inode);
129 set_nlink(inode, de->nlink);
131 generic_fillattr(inode, stat);
135 static const struct inode_operations proc_file_inode_operations = {
136 .setattr = proc_notify_change,
140 * This function parses a name such as "tty/driver/serial", and
141 * returns the struct proc_dir_entry for "/proc/tty/driver", and
142 * returns "serial" in residual.
144 static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
145 const char **residual)
147 const char *cp = name, *next;
148 struct proc_dir_entry *de;
156 next = strchr(cp, '/');
161 de = pde_subdir_find(de, cp, len);
163 WARN(1, "name '%s'\n", name);
173 static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
174 const char **residual)
178 read_lock(&proc_subdir_lock);
179 rv = __xlate_proc_name(name, ret, residual);
180 read_unlock(&proc_subdir_lock);
184 static DEFINE_IDA(proc_inum_ida);
186 #define PROC_DYNAMIC_FIRST 0xF0000000U
189 * Return an inode number between PROC_DYNAMIC_FIRST and
190 * 0xffffffff, or zero on failure.
192 int proc_alloc_inum(unsigned int *inum)
196 i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
201 *inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
205 void proc_free_inum(unsigned int inum)
207 ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
211 * Don't create negative dentries here, return -ENOENT by hand
214 struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
215 struct dentry *dentry)
219 read_lock(&proc_subdir_lock);
220 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
223 read_unlock(&proc_subdir_lock);
224 inode = proc_get_inode(dir->i_sb, de);
226 return ERR_PTR(-ENOMEM);
227 d_set_d_op(dentry, &simple_dentry_operations);
228 d_add(dentry, inode);
231 read_unlock(&proc_subdir_lock);
232 return ERR_PTR(-ENOENT);
235 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
238 return proc_lookup_de(PDE(dir), dir, dentry);
242 * This returns non-zero if at EOF, so that the /proc
243 * root directory can use this and check if it should
244 * continue with the <pid> entries..
246 * Note that the VFS-layer doesn't care about the return
247 * value of the readdir() call, as long as it's non-negative
250 int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
251 struct dir_context *ctx)
255 if (!dir_emit_dots(file, ctx))
258 read_lock(&proc_subdir_lock);
259 de = pde_subdir_first(de);
263 read_unlock(&proc_subdir_lock);
268 de = pde_subdir_next(de);
273 struct proc_dir_entry *next;
275 read_unlock(&proc_subdir_lock);
276 if (!dir_emit(ctx, de->name, de->namelen,
277 de->low_ino, de->mode >> 12)) {
281 read_lock(&proc_subdir_lock);
283 next = pde_subdir_next(de);
287 read_unlock(&proc_subdir_lock);
291 int proc_readdir(struct file *file, struct dir_context *ctx)
293 struct inode *inode = file_inode(file);
295 return proc_readdir_de(PDE(inode), file, ctx);
299 * These are the generic /proc directory operations. They
300 * use the in-memory "struct proc_dir_entry" tree to parse
301 * the /proc directory.
303 static const struct file_operations proc_dir_operations = {
304 .llseek = generic_file_llseek,
305 .read = generic_read_dir,
306 .iterate_shared = proc_readdir,
310 * proc directories can do almost nothing..
312 static const struct inode_operations proc_dir_inode_operations = {
313 .lookup = proc_lookup,
314 .getattr = proc_getattr,
315 .setattr = proc_notify_change,
318 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
322 ret = proc_alloc_inum(&dp->low_ino);
326 write_lock(&proc_subdir_lock);
328 if (pde_subdir_insert(dir, dp) == false) {
329 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
330 dir->name, dp->name);
331 write_unlock(&proc_subdir_lock);
332 proc_free_inum(dp->low_ino);
335 write_unlock(&proc_subdir_lock);
340 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
345 struct proc_dir_entry *ent = NULL;
349 if (xlate_proc_name(name, parent, &fn) != 0)
352 qstr.len = strlen(fn);
353 if (qstr.len == 0 || qstr.len >= 256) {
354 WARN(1, "name len %u\n", qstr.len);
357 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
358 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
361 if (is_empty_pde(*parent)) {
362 WARN(1, "attempt to add to permanently empty directory");
366 ent = kzalloc(sizeof(struct proc_dir_entry) + qstr.len + 1, GFP_KERNEL);
370 memcpy(ent->name, fn, qstr.len + 1);
371 ent->namelen = qstr.len;
374 ent->subdir = RB_ROOT_CACHED;
375 atomic_set(&ent->count, 1);
376 spin_lock_init(&ent->pde_unload_lock);
377 INIT_LIST_HEAD(&ent->pde_openers);
378 proc_set_user(ent, (*parent)->uid, (*parent)->gid);
384 struct proc_dir_entry *proc_symlink(const char *name,
385 struct proc_dir_entry *parent, const char *dest)
387 struct proc_dir_entry *ent;
389 ent = __proc_create(&parent, name,
390 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
393 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
395 strcpy((char*)ent->data,dest);
396 ent->proc_iops = &proc_link_inode_operations;
397 if (proc_register(parent, ent) < 0) {
409 EXPORT_SYMBOL(proc_symlink);
411 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
412 struct proc_dir_entry *parent, void *data)
414 struct proc_dir_entry *ent;
417 mode = S_IRUGO | S_IXUGO;
419 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
422 ent->proc_fops = &proc_dir_operations;
423 ent->proc_iops = &proc_dir_inode_operations;
425 if (proc_register(parent, ent) < 0) {
433 EXPORT_SYMBOL_GPL(proc_mkdir_data);
435 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
436 struct proc_dir_entry *parent)
438 return proc_mkdir_data(name, mode, parent, NULL);
440 EXPORT_SYMBOL(proc_mkdir_mode);
442 struct proc_dir_entry *proc_mkdir(const char *name,
443 struct proc_dir_entry *parent)
445 return proc_mkdir_data(name, 0, parent, NULL);
447 EXPORT_SYMBOL(proc_mkdir);
449 struct proc_dir_entry *proc_create_mount_point(const char *name)
451 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
452 struct proc_dir_entry *ent, *parent = NULL;
454 ent = __proc_create(&parent, name, mode, 2);
457 ent->proc_fops = NULL;
458 ent->proc_iops = NULL;
460 if (proc_register(parent, ent) < 0) {
468 EXPORT_SYMBOL(proc_create_mount_point);
470 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
471 struct proc_dir_entry *parent,
472 const struct file_operations *proc_fops,
475 struct proc_dir_entry *pde;
476 if ((mode & S_IFMT) == 0)
479 if (!S_ISREG(mode)) {
480 WARN_ON(1); /* use proc_mkdir() */
484 BUG_ON(proc_fops == NULL);
486 if ((mode & S_IALLUGO) == 0)
488 pde = __proc_create(&parent, name, mode, 1);
491 pde->proc_fops = proc_fops;
493 pde->proc_iops = &proc_file_inode_operations;
494 if (proc_register(parent, pde) < 0)
502 EXPORT_SYMBOL(proc_create_data);
504 struct proc_dir_entry *proc_create(const char *name, umode_t mode,
505 struct proc_dir_entry *parent,
506 const struct file_operations *proc_fops)
508 return proc_create_data(name, mode, parent, proc_fops, NULL);
510 EXPORT_SYMBOL(proc_create);
512 void proc_set_size(struct proc_dir_entry *de, loff_t size)
516 EXPORT_SYMBOL(proc_set_size);
518 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
523 EXPORT_SYMBOL(proc_set_user);
525 static void free_proc_entry(struct proc_dir_entry *de)
527 proc_free_inum(de->low_ino);
529 if (S_ISLNK(de->mode))
534 void pde_put(struct proc_dir_entry *pde)
536 if (atomic_dec_and_test(&pde->count))
537 free_proc_entry(pde);
541 * Remove a /proc entry and free it if it's not currently in use.
543 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
545 struct proc_dir_entry *de = NULL;
546 const char *fn = name;
549 write_lock(&proc_subdir_lock);
550 if (__xlate_proc_name(name, &parent, &fn) != 0) {
551 write_unlock(&proc_subdir_lock);
556 de = pde_subdir_find(parent, fn, len);
558 rb_erase_cached(&de->subdir_node, &parent->subdir);
559 write_unlock(&proc_subdir_lock);
561 WARN(1, "name '%s'\n", name);
565 proc_entry_rundown(de);
567 if (S_ISDIR(de->mode))
570 WARN(pde_subdir_first(de),
571 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
572 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
575 EXPORT_SYMBOL(remove_proc_entry);
577 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
579 struct proc_dir_entry *root = NULL, *de, *next;
580 const char *fn = name;
583 write_lock(&proc_subdir_lock);
584 if (__xlate_proc_name(name, &parent, &fn) != 0) {
585 write_unlock(&proc_subdir_lock);
590 root = pde_subdir_find(parent, fn, len);
592 write_unlock(&proc_subdir_lock);
595 rb_erase_cached(&root->subdir_node, &parent->subdir);
599 next = pde_subdir_first(de);
601 rb_erase_cached(&next->subdir_node, &de->subdir);
605 write_unlock(&proc_subdir_lock);
607 proc_entry_rundown(de);
609 if (S_ISDIR(de->mode))
616 write_lock(&proc_subdir_lock);
622 EXPORT_SYMBOL(remove_proc_subtree);
624 void *proc_get_parent_data(const struct inode *inode)
626 struct proc_dir_entry *de = PDE(inode);
627 return de->parent->data;
629 EXPORT_SYMBOL_GPL(proc_get_parent_data);
631 void proc_remove(struct proc_dir_entry *de)
634 remove_proc_subtree(de->name, de->parent);
636 EXPORT_SYMBOL(proc_remove);
638 void *PDE_DATA(const struct inode *inode)
640 return __PDE_DATA(inode);
642 EXPORT_SYMBOL(PDE_DATA);