| /* |
| * file.c - part of debugfs, a tiny little debug file system |
| * |
| * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> |
| * Copyright (C) 2004 IBM Inc. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License version |
| * 2 as published by the Free Software Foundation. |
| * |
| * debugfs is for people to use instead of /proc or /sys. |
| * See Documentation/DocBook/kernel-api for more details. |
| * |
| */ |
| |
| /* uncomment to get debug messages from the debug filesystem, ah the irony. */ |
| /* #define DEBUG */ |
| |
| #include <linux/module.h> |
| #include <linux/fs.h> |
| #include <linux/mount.h> |
| #include <linux/pagemap.h> |
| #include <linux/init.h> |
| #include <linux/kobject.h> |
| #include <linux/namei.h> |
| #include <linux/debugfs.h> |
| #include <linux/fsnotify.h> |
| #include <linux/string.h> |
| |
| #define DEBUGFS_MAGIC 0x64626720 |
| |
| /* declared over in file.c */ |
| extern struct file_operations debugfs_file_operations; |
| extern struct inode_operations debugfs_link_operations; |
| |
| static struct vfsmount *debugfs_mount; |
| static int debugfs_mount_count; |
| |
| static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev) |
| { |
| struct inode *inode = new_inode(sb); |
| |
| if (inode) { |
| inode->i_mode = mode; |
| inode->i_uid = 0; |
| inode->i_gid = 0; |
| inode->i_blocks = 0; |
| inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| switch (mode & S_IFMT) { |
| default: |
| init_special_inode(inode, mode, dev); |
| break; |
| case S_IFREG: |
| inode->i_fop = &debugfs_file_operations; |
| break; |
| case S_IFLNK: |
| inode->i_op = &debugfs_link_operations; |
| break; |
| case S_IFDIR: |
| inode->i_op = &simple_dir_inode_operations; |
| inode->i_fop = &simple_dir_operations; |
| |
| /* directory inodes start off with i_nlink == 2 |
| * (for "." entry) */ |
| inc_nlink(inode); |
| break; |
| } |
| } |
| return inode; |
| } |
| |
| /* SMP-safe */ |
| static int debugfs_mknod(struct inode *dir, struct dentry *dentry, |
| int mode, dev_t dev) |
| { |
| struct inode *inode; |
| int error = -EPERM; |
| |
| if (dentry->d_inode) |
| return -EEXIST; |
| |
| inode = debugfs_get_inode(dir->i_sb, mode, dev); |
| if (inode) { |
| d_instantiate(dentry, inode); |
| dget(dentry); |
| error = 0; |
| } |
| return error; |
| } |
| |
| static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
| { |
| int res; |
| |
| mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR; |
| res = debugfs_mknod(dir, dentry, mode, 0); |
| if (!res) { |
| inc_nlink(dir); |
| fsnotify_mkdir(dir, dentry); |
| } |
| return res; |
| } |
| |
| static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode) |
| { |
| mode = (mode & S_IALLUGO) | S_IFLNK; |
| return debugfs_mknod(dir, dentry, mode, 0); |
| } |
| |
| static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode) |
| { |
| int res; |
| |
| mode = (mode & S_IALLUGO) | S_IFREG; |
| res = debugfs_mknod(dir, dentry, mode, 0); |
| if (!res) |
| fsnotify_create(dir, dentry); |
| return res; |
| } |
| |
| static inline int debugfs_positive(struct dentry *dentry) |
| { |
| return dentry->d_inode && !d_unhashed(dentry); |
| } |
| |
| static int debug_fill_super(struct super_block *sb, void *data, int silent) |
| { |
| static struct tree_descr debug_files[] = {{""}}; |
| |
| return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); |
| } |
| |
| static int debug_get_sb(struct file_system_type *fs_type, |
| int flags, const char *dev_name, |
| void *data, struct vfsmount *mnt) |
| { |
| return get_sb_single(fs_type, flags, data, debug_fill_super, mnt); |
| } |
| |
| static struct file_system_type debug_fs_type = { |
| .owner = THIS_MODULE, |
| .name = "debugfs", |
| .get_sb = debug_get_sb, |
| .kill_sb = kill_litter_super, |
| }; |
| |
| static int debugfs_create_by_name(const char *name, mode_t mode, |
| struct dentry *parent, |
| struct dentry **dentry) |
| { |
| int error = 0; |
| |
| /* If the parent is not specified, we create it in the root. |
| * We need the root dentry to do this, which is in the super |
| * block. A pointer to that is in the struct vfsmount that we |
| * have around. |
| */ |
| if (!parent) { |
| if (debugfs_mount && debugfs_mount->mnt_sb) { |
| parent = debugfs_mount->mnt_sb->s_root; |
| } |
| } |
| if (!parent) { |
| pr_debug("debugfs: Ah! can not find a parent!\n"); |
| return -EFAULT; |
| } |
| |
| *dentry = NULL; |
| mutex_lock(&parent->d_inode->i_mutex); |
| *dentry = lookup_one_len(name, parent, strlen(name)); |
| if (!IS_ERR(*dentry)) { |
| switch (mode & S_IFMT) { |
| case S_IFDIR: |
| error = debugfs_mkdir(parent->d_inode, *dentry, mode); |
| break; |
| case S_IFLNK: |
| error = debugfs_link(parent->d_inode, *dentry, mode); |
| break; |
| default: |
| error = debugfs_create(parent->d_inode, *dentry, mode); |
| break; |
| } |
| dput(*dentry); |
| } else |
| error = PTR_ERR(*dentry); |
| mutex_unlock(&parent->d_inode->i_mutex); |
| |
| return error; |
| } |
| |
| /** |
| * debugfs_create_file - create a file in the debugfs filesystem |
| * @name: a pointer to a string containing the name of the file to create. |
| * @mode: the permission that the file should have |
| * @parent: a pointer to the parent dentry for this file. This should be a |
| * directory dentry if set. If this paramater is NULL, then the |
| * file will be created in the root of the debugfs filesystem. |
| * @data: a pointer to something that the caller will want to get to later |
| * on. The inode.i_private pointer will point to this value on |
| * the open() call. |
| * @fops: a pointer to a struct file_operations that should be used for |
| * this file. |
| * |
| * This is the basic "create a file" function for debugfs. It allows for a |
| * wide range of flexibility in createing a file, or a directory (if you |
| * want to create a directory, the debugfs_create_dir() function is |
| * recommended to be used instead.) |
| * |
| * This function will return a pointer to a dentry if it succeeds. This |
| * pointer must be passed to the debugfs_remove() function when the file is |
| * to be removed (no automatic cleanup happens if your module is unloaded, |
| * you are responsible here.) If an error occurs, %NULL will be returned. |
| * |
| * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| * returned. |
| */ |
| struct dentry *debugfs_create_file(const char *name, mode_t mode, |
| struct dentry *parent, void *data, |
| const struct file_operations *fops) |
| { |
| struct dentry *dentry = NULL; |
| int error; |
| |
| pr_debug("debugfs: creating file '%s'\n",name); |
| |
| error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
| &debugfs_mount_count); |
| if (error) |
| goto exit; |
| |
| error = debugfs_create_by_name(name, mode, parent, &dentry); |
| if (error) { |
| dentry = NULL; |
| simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
| goto exit; |
| } |
| |
| if (dentry->d_inode) { |
| if (data) |
| dentry->d_inode->i_private = data; |
| if (fops) |
| dentry->d_inode->i_fop = fops; |
| } |
| exit: |
| return dentry; |
| } |
| EXPORT_SYMBOL_GPL(debugfs_create_file); |
| |
| /** |
| * debugfs_create_dir - create a directory in the debugfs filesystem |
| * @name: a pointer to a string containing the name of the directory to |
| * create. |
| * @parent: a pointer to the parent dentry for this file. This should be a |
| * directory dentry if set. If this paramater is NULL, then the |
| * directory will be created in the root of the debugfs filesystem. |
| * |
| * This function creates a directory in debugfs with the given name. |
| * |
| * This function will return a pointer to a dentry if it succeeds. This |
| * pointer must be passed to the debugfs_remove() function when the file is |
| * to be removed (no automatic cleanup happens if your module is unloaded, |
| * you are responsible here.) If an error occurs, %NULL will be returned. |
| * |
| * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| * returned. |
| */ |
| struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) |
| { |
| return debugfs_create_file(name, |
| S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, |
| parent, NULL, NULL); |
| } |
| EXPORT_SYMBOL_GPL(debugfs_create_dir); |
| |
| /** |
| * debugfs_create_symlink- create a symbolic link in the debugfs filesystem |
| * @name: a pointer to a string containing the name of the symbolic link to |
| * create. |
| * @parent: a pointer to the parent dentry for this symbolic link. This |
| * should be a directory dentry if set. If this paramater is NULL, |
| * then the symbolic link will be created in the root of the debugfs |
| * filesystem. |
| * @target: a pointer to a string containing the path to the target of the |
| * symbolic link. |
| * |
| * This function creates a symbolic link with the given name in debugfs that |
| * links to the given target path. |
| * |
| * This function will return a pointer to a dentry if it succeeds. This |
| * pointer must be passed to the debugfs_remove() function when the symbolic |
| * link is to be removed (no automatic cleanup happens if your module is |
| * unloaded, you are responsible here.) If an error occurs, %NULL will be |
| * returned. |
| * |
| * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| * returned. |
| */ |
| struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, |
| const char *target) |
| { |
| struct dentry *result; |
| char *link; |
| |
| link = kstrdup(target, GFP_KERNEL); |
| if (!link) |
| return NULL; |
| |
| result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link, |
| NULL); |
| if (!result) |
| kfree(link); |
| return result; |
| } |
| EXPORT_SYMBOL_GPL(debugfs_create_symlink); |
| |
| /** |
| * debugfs_remove - removes a file or directory from the debugfs filesystem |
| * @dentry: a pointer to a the dentry of the file or directory to be |
| * removed. |
| * |
| * This function removes a file or directory in debugfs that was previously |
| * created with a call to another debugfs function (like |
| * debugfs_create_file() or variants thereof.) |
| * |
| * This function is required to be called in order for the file to be |
| * removed, no automatic cleanup of files will happen when a module is |
| * removed, you are responsible here. |
| */ |
| void debugfs_remove(struct dentry *dentry) |
| { |
| struct dentry *parent; |
| int ret = 0; |
| |
| if (!dentry) |
| return; |
| |
| parent = dentry->d_parent; |
| if (!parent || !parent->d_inode) |
| return; |
| |
| mutex_lock(&parent->d_inode->i_mutex); |
| if (debugfs_positive(dentry)) { |
| if (dentry->d_inode) { |
| dget(dentry); |
| switch (dentry->d_inode->i_mode & S_IFMT) { |
| case S_IFDIR: |
| ret = simple_rmdir(parent->d_inode, dentry); |
| break; |
| case S_IFLNK: |
| kfree(dentry->d_inode->i_private); |
| /* fall through */ |
| default: |
| simple_unlink(parent->d_inode, dentry); |
| break; |
| } |
| if (!ret) |
| d_delete(dentry); |
| dput(dentry); |
| } |
| } |
| mutex_unlock(&parent->d_inode->i_mutex); |
| simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
| } |
| EXPORT_SYMBOL_GPL(debugfs_remove); |
| |
| /** |
| * debugfs_rename - rename a file/directory in the debugfs filesystem |
| * @old_dir: a pointer to the parent dentry for the renamed object. This |
| * should be a directory dentry. |
| * @old_dentry: dentry of an object to be renamed. |
| * @new_dir: a pointer to the parent dentry where the object should be |
| * moved. This should be a directory dentry. |
| * @new_name: a pointer to a string containing the target name. |
| * |
| * This function renames a file/directory in debugfs. The target must not |
| * exist for rename to succeed. |
| * |
| * This function will return a pointer to old_dentry (which is updated to |
| * reflect renaming) if it succeeds. If an error occurs, %NULL will be |
| * returned. |
| * |
| * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
| * returned. |
| */ |
| struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, |
| struct dentry *new_dir, const char *new_name) |
| { |
| int error; |
| struct dentry *dentry = NULL, *trap; |
| const char *old_name; |
| |
| trap = lock_rename(new_dir, old_dir); |
| /* Source or destination directories don't exist? */ |
| if (!old_dir->d_inode || !new_dir->d_inode) |
| goto exit; |
| /* Source does not exist, cyclic rename, or mountpoint? */ |
| if (!old_dentry->d_inode || old_dentry == trap || |
| d_mountpoint(old_dentry)) |
| goto exit; |
| dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); |
| /* Lookup failed, cyclic rename or target exists? */ |
| if (IS_ERR(dentry) || dentry == trap || dentry->d_inode) |
| goto exit; |
| |
| old_name = fsnotify_oldname_init(old_dentry->d_name.name); |
| |
| error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, |
| dentry); |
| if (error) { |
| fsnotify_oldname_free(old_name); |
| goto exit; |
| } |
| d_move(old_dentry, dentry); |
| fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name, |
| old_dentry->d_name.name, S_ISDIR(old_dentry->d_inode->i_mode), |
| NULL, old_dentry); |
| fsnotify_oldname_free(old_name); |
| unlock_rename(new_dir, old_dir); |
| dput(dentry); |
| return old_dentry; |
| exit: |
| if (dentry && !IS_ERR(dentry)) |
| dput(dentry); |
| unlock_rename(new_dir, old_dir); |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(debugfs_rename); |
| |
| static struct kobject *debug_kobj; |
| |
| static int __init debugfs_init(void) |
| { |
| int retval; |
| |
| debug_kobj = kobject_create_and_add("debug", kernel_kobj); |
| if (!debug_kobj) |
| return -EINVAL; |
| |
| retval = register_filesystem(&debug_fs_type); |
| if (retval) |
| kobject_unregister(debug_kobj); |
| return retval; |
| } |
| |
| static void __exit debugfs_exit(void) |
| { |
| simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
| unregister_filesystem(&debug_fs_type); |
| kobject_unregister(debug_kobj); |
| } |
| |
| core_initcall(debugfs_init); |
| module_exit(debugfs_exit); |
| MODULE_LICENSE("GPL"); |
| |