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);
183 static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
185 #define PROC_DYNAMIC_FIRST 0xF0000000U
188 * Return an inode number between PROC_DYNAMIC_FIRST and
189 * 0xffffffff, or zero on failure.
191 int proc_alloc_inum(unsigned int *inum)
197 if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
200 spin_lock_irq(&proc_inum_lock);
201 error = ida_get_new(&proc_inum_ida, &i);
202 spin_unlock_irq(&proc_inum_lock);
203 if (error == -EAGAIN)
208 if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
209 spin_lock_irq(&proc_inum_lock);
210 ida_remove(&proc_inum_ida, i);
211 spin_unlock_irq(&proc_inum_lock);
214 *inum = PROC_DYNAMIC_FIRST + i;
218 void proc_free_inum(unsigned int inum)
221 spin_lock_irqsave(&proc_inum_lock, flags);
222 ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
223 spin_unlock_irqrestore(&proc_inum_lock, flags);
227 * Don't create negative dentries here, return -ENOENT by hand
230 struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
231 struct dentry *dentry)
235 read_lock(&proc_subdir_lock);
236 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
239 read_unlock(&proc_subdir_lock);
240 inode = proc_get_inode(dir->i_sb, de);
242 return ERR_PTR(-ENOMEM);
243 d_set_d_op(dentry, &simple_dentry_operations);
244 d_add(dentry, inode);
247 read_unlock(&proc_subdir_lock);
248 return ERR_PTR(-ENOENT);
251 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
254 return proc_lookup_de(PDE(dir), dir, dentry);
258 * This returns non-zero if at EOF, so that the /proc
259 * root directory can use this and check if it should
260 * continue with the <pid> entries..
262 * Note that the VFS-layer doesn't care about the return
263 * value of the readdir() call, as long as it's non-negative
266 int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
267 struct dir_context *ctx)
271 if (!dir_emit_dots(file, ctx))
274 read_lock(&proc_subdir_lock);
275 de = pde_subdir_first(de);
279 read_unlock(&proc_subdir_lock);
284 de = pde_subdir_next(de);
289 struct proc_dir_entry *next;
291 read_unlock(&proc_subdir_lock);
292 if (!dir_emit(ctx, de->name, de->namelen,
293 de->low_ino, de->mode >> 12)) {
297 read_lock(&proc_subdir_lock);
299 next = pde_subdir_next(de);
303 read_unlock(&proc_subdir_lock);
307 int proc_readdir(struct file *file, struct dir_context *ctx)
309 struct inode *inode = file_inode(file);
311 return proc_readdir_de(PDE(inode), file, ctx);
315 * These are the generic /proc directory operations. They
316 * use the in-memory "struct proc_dir_entry" tree to parse
317 * the /proc directory.
319 static const struct file_operations proc_dir_operations = {
320 .llseek = generic_file_llseek,
321 .read = generic_read_dir,
322 .iterate_shared = proc_readdir,
326 * proc directories can do almost nothing..
328 static const struct inode_operations proc_dir_inode_operations = {
329 .lookup = proc_lookup,
330 .getattr = proc_getattr,
331 .setattr = proc_notify_change,
334 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
338 ret = proc_alloc_inum(&dp->low_ino);
342 write_lock(&proc_subdir_lock);
344 if (pde_subdir_insert(dir, dp) == false) {
345 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
346 dir->name, dp->name);
347 write_unlock(&proc_subdir_lock);
348 proc_free_inum(dp->low_ino);
351 write_unlock(&proc_subdir_lock);
356 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
361 struct proc_dir_entry *ent = NULL;
365 if (xlate_proc_name(name, parent, &fn) != 0)
368 qstr.len = strlen(fn);
369 if (qstr.len == 0 || qstr.len >= 256) {
370 WARN(1, "name len %u\n", qstr.len);
373 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
374 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
377 if (is_empty_pde(*parent)) {
378 WARN(1, "attempt to add to permanently empty directory");
382 ent = kzalloc(sizeof(struct proc_dir_entry) + qstr.len + 1, GFP_KERNEL);
386 memcpy(ent->name, fn, qstr.len + 1);
387 ent->namelen = qstr.len;
390 ent->subdir = RB_ROOT;
391 atomic_set(&ent->count, 1);
392 spin_lock_init(&ent->pde_unload_lock);
393 INIT_LIST_HEAD(&ent->pde_openers);
394 proc_set_user(ent, (*parent)->uid, (*parent)->gid);
400 struct proc_dir_entry *proc_symlink(const char *name,
401 struct proc_dir_entry *parent, const char *dest)
403 struct proc_dir_entry *ent;
405 ent = __proc_create(&parent, name,
406 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
409 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
411 strcpy((char*)ent->data,dest);
412 ent->proc_iops = &proc_link_inode_operations;
413 if (proc_register(parent, ent) < 0) {
425 EXPORT_SYMBOL(proc_symlink);
427 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
428 struct proc_dir_entry *parent, void *data)
430 struct proc_dir_entry *ent;
433 mode = S_IRUGO | S_IXUGO;
435 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
438 ent->proc_fops = &proc_dir_operations;
439 ent->proc_iops = &proc_dir_inode_operations;
441 if (proc_register(parent, ent) < 0) {
449 EXPORT_SYMBOL_GPL(proc_mkdir_data);
451 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
452 struct proc_dir_entry *parent)
454 return proc_mkdir_data(name, mode, parent, NULL);
456 EXPORT_SYMBOL(proc_mkdir_mode);
458 struct proc_dir_entry *proc_mkdir(const char *name,
459 struct proc_dir_entry *parent)
461 return proc_mkdir_data(name, 0, parent, NULL);
463 EXPORT_SYMBOL(proc_mkdir);
465 struct proc_dir_entry *proc_create_mount_point(const char *name)
467 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
468 struct proc_dir_entry *ent, *parent = NULL;
470 ent = __proc_create(&parent, name, mode, 2);
473 ent->proc_fops = NULL;
474 ent->proc_iops = NULL;
476 if (proc_register(parent, ent) < 0) {
484 EXPORT_SYMBOL(proc_create_mount_point);
486 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
487 struct proc_dir_entry *parent,
488 const struct file_operations *proc_fops,
491 struct proc_dir_entry *pde;
492 if ((mode & S_IFMT) == 0)
495 if (!S_ISREG(mode)) {
496 WARN_ON(1); /* use proc_mkdir() */
500 BUG_ON(proc_fops == NULL);
502 if ((mode & S_IALLUGO) == 0)
504 pde = __proc_create(&parent, name, mode, 1);
507 pde->proc_fops = proc_fops;
509 pde->proc_iops = &proc_file_inode_operations;
510 if (proc_register(parent, pde) < 0)
518 EXPORT_SYMBOL(proc_create_data);
520 void proc_set_size(struct proc_dir_entry *de, loff_t size)
524 EXPORT_SYMBOL(proc_set_size);
526 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
531 EXPORT_SYMBOL(proc_set_user);
533 static void free_proc_entry(struct proc_dir_entry *de)
535 proc_free_inum(de->low_ino);
537 if (S_ISLNK(de->mode))
542 void pde_put(struct proc_dir_entry *pde)
544 if (atomic_dec_and_test(&pde->count))
545 free_proc_entry(pde);
549 * Remove a /proc entry and free it if it's not currently in use.
551 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
553 struct proc_dir_entry *de = NULL;
554 const char *fn = name;
557 write_lock(&proc_subdir_lock);
558 if (__xlate_proc_name(name, &parent, &fn) != 0) {
559 write_unlock(&proc_subdir_lock);
564 de = pde_subdir_find(parent, fn, len);
566 rb_erase(&de->subdir_node, &parent->subdir);
567 write_unlock(&proc_subdir_lock);
569 WARN(1, "name '%s'\n", name);
573 proc_entry_rundown(de);
575 if (S_ISDIR(de->mode))
578 WARN(pde_subdir_first(de),
579 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
580 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
583 EXPORT_SYMBOL(remove_proc_entry);
585 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
587 struct proc_dir_entry *root = NULL, *de, *next;
588 const char *fn = name;
591 write_lock(&proc_subdir_lock);
592 if (__xlate_proc_name(name, &parent, &fn) != 0) {
593 write_unlock(&proc_subdir_lock);
598 root = pde_subdir_find(parent, fn, len);
600 write_unlock(&proc_subdir_lock);
603 rb_erase(&root->subdir_node, &parent->subdir);
607 next = pde_subdir_first(de);
609 rb_erase(&next->subdir_node, &de->subdir);
613 write_unlock(&proc_subdir_lock);
615 proc_entry_rundown(de);
617 if (S_ISDIR(de->mode))
624 write_lock(&proc_subdir_lock);
630 EXPORT_SYMBOL(remove_proc_subtree);
632 void *proc_get_parent_data(const struct inode *inode)
634 struct proc_dir_entry *de = PDE(inode);
635 return de->parent->data;
637 EXPORT_SYMBOL_GPL(proc_get_parent_data);
639 void proc_remove(struct proc_dir_entry *de)
642 remove_proc_subtree(de->name, de->parent);
644 EXPORT_SYMBOL(proc_remove);
646 void *PDE_DATA(const struct inode *inode)
648 return __PDE_DATA(inode);
650 EXPORT_SYMBOL(PDE_DATA);