/* *  inode.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. * */ #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>#include <linux/magic.h>#include <linux/slab.h> static struct vfsmount *debugfs_mount;static int debugfs_mount_count;static bool debugfs_registered; static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev_t dev,				       void *data, const struct file_operations *fops) {	struct inode *inode = new_inode(sb); 	if (inode) {		inode->i_ino = get_next_ino();		inode->i_mode = mode;		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 = fops ? fops : &debugfs_file_operations;			inode->i_private = data;			break;		case S_IFLNK:			inode->i_op = &debugfs_link_operations;			inode->i_fop = fops;			inode->i_private = data;			break;		case S_IFDIR:			inode->i_op = &simple_dir_inode_operations;			inode->i_fop = fops ? fops : &simple_dir_operations;			inode->i_private = data; 			/* 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,			 umode_t mode, dev_t dev, void *data,			 const struct file_operations *fops){	struct inode *inode;	int error = -EPERM; 	if (dentry->d_inode)		return -EEXIST; 	inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);	if (inode) {		d_instantiate(dentry, inode);		dget(dentry);		error = 0;	}	return error;} static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode,			 void *data, const struct file_operations *fops){	int res; 	mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;	res = debugfs_mknod(dir, dentry, mode, 0, data, fops);	if (!res) {		inc_nlink(dir);		fsnotify_mkdir(dir, dentry);	}	return res;} static int debugfs_link(struct inode *dir, struct dentry *dentry, umode_t mode,			void *data, const struct file_operations *fops){	mode = (mode & S_IALLUGO) | S_IFLNK;	return debugfs_mknod(dir, dentry, mode, 0, data, fops);} static int debugfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,			  void *data, const struct file_operations *fops){	int res; 	mode = (mode & S_IALLUGO) | S_IFREG;	res = debugfs_mknod(dir, dentry, mode, 0, data, fops);	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 struct dentry *debug_mount(struct file_system_type *fs_type,			int flags, const char *dev_name,			void *data){	return mount_single(fs_type, flags, data, debug_fill_super);} static struct file_system_type debug_fs_type = {	.owner =	THIS_MODULE,	.name =		"debugfs",	.mount =	debug_mount,	.kill_sb =	kill_litter_super,}; static int debugfs_create_by_name(const char *name, umode_t mode,				  struct dentry *parent,				  struct dentry **dentry,				  void *data,				  const struct file_operations *fops){	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)		parent = debugfs_mount->mnt_root; 	*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,					      data, fops);			break;		case S_IFLNK:			error = debugfs_link(parent->d_inode, *dentry, mode,					     data, fops);			break;		default:			error = debugfs_create(parent->d_inode, *dentry, mode,					       data, fops);			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 creating 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, umode_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,				       data, fops);	if (error) {		dentry = NULL;		simple_release_fs(&debugfs_mount, &debugfs_mount_count);		goto exit;	}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); static int __debugfs_remove(struct dentry *dentry, struct dentry *parent){	int ret = 0; 	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);		}	}	return ret;} /** * 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; 	if (!dentry)		return; 	parent = dentry->d_parent;	if (!parent || !parent->d_inode)		return; 	mutex_lock(&parent->d_inode->i_mutex);	ret = __debugfs_remove(dentry, parent);	mutex_unlock(&parent->d_inode->i_mutex);	if (!ret)		simple_release_fs(&debugfs_mount, &debugfs_mount_count);}EXPORT_SYMBOL_GPL(debugfs_remove); /** * debugfs_remove_recursive - recursively removes a directory * @dentry: a pointer to a the dentry of the directory to be removed. * * This function recursively removes a directory tree 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_recursive(struct dentry *dentry){	struct dentry *child;	struct dentry *parent; 	if (!dentry)		return; 	parent = dentry->d_parent;	if (!parent || !parent->d_inode)		return; 	parent = dentry;	mutex_lock(&parent->d_inode->i_mutex); 	while (1) {		/*		 * When all dentries under "parent" has been removed,		 * walk up the tree until we reach our starting point.		 */		if (list_empty(&parent->d_subdirs)) {			mutex_unlock(&parent->d_inode->i_mutex);			if (parent == dentry)				break;			parent = parent->d_parent;			mutex_lock(&parent->d_inode->i_mutex);		}		child = list_entry(parent->d_subdirs.next, struct dentry,				d_u.d_child); next_sibling: 		/*		 * If "child" isn't empty, walk down the tree and		 * remove all its descendants first.		 */		if (!list_empty(&child->d_subdirs)) {			mutex_unlock(&parent->d_inode->i_mutex);			parent = child;			mutex_lock(&parent->d_inode->i_mutex);			continue;		}		__debugfs_remove(child, parent);		if (parent->d_subdirs.next == &child->d_u.d_child) {			/*			 * Try the next sibling.			 */			if (child->d_u.d_child.next != &parent->d_subdirs) {				child = list_entry(child->d_u.d_child.next,						   struct dentry,						   d_u.d_child);				goto next_sibling;			} 			/*			 * Avoid infinite loop if we fail to remove			 * one dentry.			 */			mutex_unlock(&parent->d_inode->i_mutex);			break;		}		simple_release_fs(&debugfs_mount, &debugfs_mount_count);	} 	parent = dentry->d_parent;	mutex_lock(&parent->d_inode->i_mutex);	__debugfs_remove(dentry, parent);	mutex_unlock(&parent->d_inode->i_mutex);	simple_release_fs(&debugfs_mount, &debugfs_mount_count);}EXPORT_SYMBOL_GPL(debugfs_remove_recursive); /** * 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,

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