Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 *  inode.c - part of debugfs, a tiny little debug file system
 *
 *  Copyright (C) 2004,2019 Greg Kroah-Hartman <greg@kroah.com>
 *  Copyright (C) 2004 IBM Inc.
 *  Copyright (C) 2019 Linux Foundation <gregkh@linuxfoundation.org>
 *
 *  debugfs is for people to use instead of /proc or /sys.
 *  See ./Documentation/core-api/kernel-api.rst for more details.
 */
 
#define pr_fmt(fmt)	"debugfs: " fmt
 
#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/seq_file.h>
#include <linux/parser.h>
#include <linux/magic.h>
#include <linux/slab.h>
#include <linux/security.h>
 
#include "internal.h"
 
#define DEBUGFS_DEFAULT_MODE	0700
 
static struct vfsmount *debugfs_mount;
static int debugfs_mount_count;
static bool debugfs_registered;
static unsigned int debugfs_allow __ro_after_init = DEFAULT_DEBUGFS_ALLOW_BITS;
 
/*
 * Don't allow access attributes to be changed whilst the kernel is locked down
 * so that we can use the file mode as part of a heuristic to determine whether
 * to lock down individual files.
 */
static int debugfs_setattr(struct dentry *dentry, struct iattr *ia)
{
<------>int ret = security_locked_down(LOCKDOWN_DEBUGFS);
 
<------>if (ret && (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)))
<------><------>return ret;
<------>return simple_setattr(dentry, ia);
}
 
static const struct inode_operations debugfs_file_inode_operations = {
<------>.setattr	= debugfs_setattr,
};
static const struct inode_operations debugfs_dir_inode_operations = {
<------>.lookup		= simple_lookup,
<------>.setattr	= debugfs_setattr,
};
static const struct inode_operations debugfs_symlink_inode_operations = {
<------>.get_link	= simple_get_link,
<------>.setattr	= debugfs_setattr,
};
 
static struct inode *debugfs_get_inode(struct super_block *sb)
{
<------>struct inode *inode = new_inode(sb);
<------>if (inode) {
<------><------>inode->i_ino = get_next_ino();
<------><------>inode->i_atime = inode->i_mtime =
<------><------><------>inode->i_ctime = current_time(inode);
<------>}
<------>return inode;
}
 
struct debugfs_mount_opts {
<------>kuid_t uid;
<------>kgid_t gid;
<------>umode_t mode;
};
 
enum {
<------>Opt_uid,
<------>Opt_gid,
<------>Opt_mode,
<------>Opt_err
};
 
static const match_table_t tokens = {
<------>{Opt_uid, "uid=%u"},
<------>{Opt_gid, "gid=%u"},
<------>{Opt_mode, "mode=%o"},
<------>{Opt_err, NULL}
};
 
struct debugfs_fs_info {
<------>struct debugfs_mount_opts mount_opts;
};
 
static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
{
<------>substring_t args[MAX_OPT_ARGS];
<------>int option;
<------>int token;
<------>kuid_t uid;
<------>kgid_t gid;
<------>char *p;
 
<------>opts->mode = DEBUGFS_DEFAULT_MODE;
 
<------>while ((p = strsep(&data, ",")) != NULL) {
<------><------>if (!*p)
<------><------><------>continue;
 
<------><------>token = match_token(p, tokens, args);
<------><------>switch (token) {
<------><------>case Opt_uid:
<------><------><------>if (match_int(&args[0], &option))
<------><------><------><------>return -EINVAL;
<------><------><------>uid = make_kuid(current_user_ns(), option);
<------><------><------>if (!uid_valid(uid))
<------><------><------><------>return -EINVAL;
<------><------><------>opts->uid = uid;
<------><------><------>break;
<------><------>case Opt_gid:
<------><------><------>if (match_int(&args[0], &option))
<------><------><------><------>return -EINVAL;
<------><------><------>gid = make_kgid(current_user_ns(), option);
<------><------><------>if (!gid_valid(gid))
<------><------><------><------>return -EINVAL;
<------><------><------>opts->gid = gid;
<------><------><------>break;
<------><------>case Opt_mode:
<------><------><------>if (match_octal(&args[0], &option))
<------><------><------><------>return -EINVAL;
<------><------><------>opts->mode = option & S_IALLUGO;
<------><------><------>break;
<------><------>/*
<------><------> * We might like to report bad mount options here;
<------><------> * but traditionally debugfs has ignored all mount options
<------><------> */
<------><------>}
<------>}
 
<------>return 0;
}
 
static int debugfs_apply_options(struct super_block *sb)
{
<------>struct debugfs_fs_info *fsi = sb->s_fs_info;
<------>struct inode *inode = d_inode(sb->s_root);
<------>struct debugfs_mount_opts *opts = &fsi->mount_opts;
 
<------>inode->i_mode &= ~S_IALLUGO;
<------>inode->i_mode |= opts->mode;
 
<------>inode->i_uid = opts->uid;
<------>inode->i_gid = opts->gid;
 
<------>return 0;
}
 
static int debugfs_remount(struct super_block *sb, int *flags, char *data)
{
<------>int err;
<------>struct debugfs_fs_info *fsi = sb->s_fs_info;
 
<------>sync_filesystem(sb);
<------>err = debugfs_parse_options(data, &fsi->mount_opts);
<------>if (err)
<------><------>goto fail;
 
<------>debugfs_apply_options(sb);
 
fail:
<------>return err;
}
 
static int debugfs_show_options(struct seq_file *m, struct dentry *root)
{
<------>struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
<------>struct debugfs_mount_opts *opts = &fsi->mount_opts;
 
<------>if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
<------><------>seq_printf(m, ",uid=%u",
<------><------><------>   from_kuid_munged(&init_user_ns, opts->uid));
<------>if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
<------><------>seq_printf(m, ",gid=%u",
<------><------><------>   from_kgid_munged(&init_user_ns, opts->gid));
<------>if (opts->mode != DEBUGFS_DEFAULT_MODE)
<------><------>seq_printf(m, ",mode=%o", opts->mode);
 
<------>return 0;
}
 
static void debugfs_free_inode(struct inode *inode)
{
<------>if (S_ISLNK(inode->i_mode))
<------><------>kfree(inode->i_link);
<------>free_inode_nonrcu(inode);
}
 
static const struct super_operations debugfs_super_operations = {
<------>.statfs		= simple_statfs,
<------>.remount_fs	= debugfs_remount,
<------>.show_options	= debugfs_show_options,
<------>.free_inode	= debugfs_free_inode,
};
 
static void debugfs_release_dentry(struct dentry *dentry)
{
<------>void *fsd = dentry->d_fsdata;
 
<------>if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))
<------><------>kfree(dentry->d_fsdata);
}
 
static struct vfsmount *debugfs_automount(struct path *path)
{
<------>debugfs_automount_t f;
<------>f = (debugfs_automount_t)path->dentry->d_fsdata;
<------>return f(path->dentry, d_inode(path->dentry)->i_private);
}
 
static const struct dentry_operations debugfs_dops = {
<------>.d_delete = always_delete_dentry,
<------>.d_release = debugfs_release_dentry,
<------>.d_automount = debugfs_automount,
};
 
static int debug_fill_super(struct super_block *sb, void *data, int silent)
{
<------>static const struct tree_descr debug_files[] = {{""}};
<------>struct debugfs_fs_info *fsi;
<------>int err;
 
<------>fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
<------>sb->s_fs_info = fsi;
<------>if (!fsi) {
<------><------>err = -ENOMEM;
<------><------>goto fail;
<------>}
 
<------>err = debugfs_parse_options(data, &fsi->mount_opts);
<------>if (err)
<------><------>goto fail;
 
<------>err  =  simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
<------>if (err)
<------><------>goto fail;
 
<------>sb->s_op = &debugfs_super_operations;
<------>sb->s_d_op = &debugfs_dops;
 
<------>debugfs_apply_options(sb);
 
<------>return 0;
 
fail:
<------>kfree(fsi);
<------>sb->s_fs_info = NULL;
<------>return err;
}
 
static struct dentry *debug_mount(struct file_system_type *fs_type,
<------><------><------>int flags, const char *dev_name,
<------><------><------>void *data)
{
<------>if (!(debugfs_allow & DEBUGFS_ALLOW_API))
<------><------>return ERR_PTR(-EPERM);
 
<------>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,
};
MODULE_ALIAS_FS("debugfs");
 
/**
 * debugfs_lookup() - look up an existing debugfs file
 * @name: a pointer to a string containing the name of the file to look up.
 * @parent: a pointer to the parent dentry of the file.
 *
 * This function will return a pointer to a dentry if it succeeds.  If the file
 * doesn't exist or an error occurs, %NULL will be returned.  The returned
 * dentry must be passed to dput() when it is no longer needed.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.
 */
struct dentry *debugfs_lookup(const char *name, struct dentry *parent)
{
<------>struct dentry *dentry;
 
<------>if (!debugfs_initialized() || IS_ERR_OR_NULL(name) || IS_ERR(parent))
<------><------>return NULL;
 
<------>if (!parent)
<------><------>parent = debugfs_mount->mnt_root;
 
<------>dentry = lookup_positive_unlocked(name, parent, strlen(name));
<------>if (IS_ERR(dentry))
<------><------>return NULL;
<------>return dentry;
}
EXPORT_SYMBOL_GPL(debugfs_lookup);
 
static struct dentry *start_creating(const char *name, struct dentry *parent)
{
<------>struct dentry *dentry;
<------>int error;
 
<------>if (!(debugfs_allow & DEBUGFS_ALLOW_API))
<------><------>return ERR_PTR(-EPERM);
 
<------>if (!debugfs_initialized())
<------><------>return ERR_PTR(-ENOENT);
 
<------>pr_debug("creating file '%s'\n", name);
 
<------>if (IS_ERR(parent))
<------><------>return parent;
 
<------>error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
<------><------><------>      &debugfs_mount_count);
<------>if (error) {
<------><------>pr_err("Unable to pin filesystem for file '%s'\n", name);
<------><------>return ERR_PTR(error);
<------>}
 
<------>/* 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;
 
<------>inode_lock(d_inode(parent));
<------>if (unlikely(IS_DEADDIR(d_inode(parent))))
<------><------>dentry = ERR_PTR(-ENOENT);
<------>else
<------><------>dentry = lookup_one_len(name, parent, strlen(name));
<------>if (!IS_ERR(dentry) && d_really_is_positive(dentry)) {
<------><------>if (d_is_dir(dentry))
<------><------><------>pr_err("Directory '%s' with parent '%s' already present!\n",
<------><------><------>       name, parent->d_name.name);
<------><------>else
<------><------><------>pr_err("File '%s' in directory '%s' already present!\n",
<------><------><------>       name, parent->d_name.name);
<------><------>dput(dentry);
<------><------>dentry = ERR_PTR(-EEXIST);
<------>}
 
<------>if (IS_ERR(dentry)) {
<------><------>inode_unlock(d_inode(parent));
<------><------>simple_release_fs(&debugfs_mount, &debugfs_mount_count);
<------>}
 
<------>return dentry;
}
 
static struct dentry *failed_creating(struct dentry *dentry)
{
<------>inode_unlock(d_inode(dentry->d_parent));
<------>dput(dentry);
<------>simple_release_fs(&debugfs_mount, &debugfs_mount_count);
<------>return ERR_PTR(-ENOMEM);
}
 
static struct dentry *end_creating(struct dentry *dentry)
{
<------>inode_unlock(d_inode(dentry->d_parent));
<------>return dentry;
}
 
static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
<------><------><------><------>struct dentry *parent, void *data,
<------><------><------><------>const struct file_operations *proxy_fops,
<------><------><------><------>const struct file_operations *real_fops)
{
<------>struct dentry *dentry;
<------>struct inode *inode;
 
<------>if (!(mode & S_IFMT))
<------><------>mode |= S_IFREG;
<------>BUG_ON(!S_ISREG(mode));
<------>dentry = start_creating(name, parent);
 
<------>if (IS_ERR(dentry))
<------><------>return dentry;
 
<------>if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
<------><------>failed_creating(dentry);
<------><------>return ERR_PTR(-EPERM);
<------>}
 
<------>inode = debugfs_get_inode(dentry->d_sb);
<------>if (unlikely(!inode)) {
<------><------>pr_err("out of free dentries, can not create file '%s'\n",
<------><------>       name);
<------><------>return failed_creating(dentry);
<------>}
 
<------>inode->i_mode = mode;
<------>inode->i_private = data;
 
<------>inode->i_op = &debugfs_file_inode_operations;
<------>inode->i_fop = proxy_fops;
<------>dentry->d_fsdata = (void *)((unsigned long)real_fops |
<------><------><------><------>DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
 
<------>d_instantiate(dentry, inode);
<------>fsnotify_create(d_inode(dentry->d_parent), dentry);
<------>return end_creating(dentry);
}
 
/**
 * 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 parameter 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, ERR_PTR(-ERROR) 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)
{
 
<------>return __debugfs_create_file(name, mode, parent, data,
<------><------><------><------>fops ? &debugfs_full_proxy_file_operations :
<------><------><------><------><------>&debugfs_noop_file_operations,
<------><------><------><------>fops);
}
EXPORT_SYMBOL_GPL(debugfs_create_file);
 
/**
 * debugfs_create_file_unsafe - 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 parameter 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.
 *
 * debugfs_create_file_unsafe() is completely analogous to
 * debugfs_create_file(), the only difference being that the fops
 * handed it will not get protected against file removals by the
 * debugfs core.
 *
 * It is your responsibility to protect your struct file_operation
 * methods against file removals by means of debugfs_file_get()
 * and debugfs_file_put(). ->open() is still protected by
 * debugfs though.
 *
 * Any struct file_operations defined by means of
 * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and
 * thus, may be used here.
 */
struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
<------><------><------><------>   struct dentry *parent, void *data,
<------><------><------><------>   const struct file_operations *fops)
{
 
<------>return __debugfs_create_file(name, mode, parent, data,
<------><------><------><------>fops ? &debugfs_open_proxy_file_operations :
<------><------><------><------><------>&debugfs_noop_file_operations,
<------><------><------><------>fops);
}
EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe);
 
/**
 * debugfs_create_file_size - 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 parameter 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.
 * @file_size: initial file size
 *
 * 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.)
 */
void debugfs_create_file_size(const char *name, umode_t mode,
<------><------><------>      struct dentry *parent, void *data,
<------><------><------>      const struct file_operations *fops,
<------><------><------>      loff_t file_size)
{
<------>struct dentry *de = debugfs_create_file(name, mode, parent, data, fops);
 
<------>if (!IS_ERR(de))
<------><------>d_inode(de)->i_size = file_size;
}
EXPORT_SYMBOL_GPL(debugfs_create_file_size);
 
/**
 * 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 parameter 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, ERR_PTR(-ERROR) 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)
{
<------>struct dentry *dentry = start_creating(name, parent);
<------>struct inode *inode;
 
<------>if (IS_ERR(dentry))
<------><------>return dentry;
 
<------>if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
<------><------>failed_creating(dentry);
<------><------>return ERR_PTR(-EPERM);
<------>}
 
<------>inode = debugfs_get_inode(dentry->d_sb);
<------>if (unlikely(!inode)) {
<------><------>pr_err("out of free dentries, can not create directory '%s'\n",
<------><------>       name);
<------><------>return failed_creating(dentry);
<------>}
 
<------>inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
<------>inode->i_op = &debugfs_dir_inode_operations;
<------>inode->i_fop = &simple_dir_operations;
 
<------>/* directory inodes start off with i_nlink == 2 (for "." entry) */
<------>inc_nlink(inode);
<------>d_instantiate(dentry, inode);
<------>inc_nlink(d_inode(dentry->d_parent));
<------>fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
<------>return end_creating(dentry);
}
EXPORT_SYMBOL_GPL(debugfs_create_dir);
 
/**
 * debugfs_create_automount - create automount point in the debugfs filesystem
 * @name: a pointer to a string containing the name of the file to create.
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @f: function to be called when pathname resolution steps on that one.
 * @data: opaque argument to pass to f().
 *
 * @f should return what ->d_automount() would.
 */
struct dentry *debugfs_create_automount(const char *name,
<------><------><------><------><------>struct dentry *parent,
<------><------><------><------><------>debugfs_automount_t f,
<------><------><------><------><------>void *data)
{
<------>struct dentry *dentry = start_creating(name, parent);
<------>struct inode *inode;
 
<------>if (IS_ERR(dentry))
<------><------>return dentry;
 
<------>if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
<------><------>failed_creating(dentry);
<------><------>return ERR_PTR(-EPERM);
<------>}
 
<------>inode = debugfs_get_inode(dentry->d_sb);
<------>if (unlikely(!inode)) {
<------><------>pr_err("out of free dentries, can not create automount '%s'\n",
<------><------>       name);
<------><------>return failed_creating(dentry);
<------>}
 
<------>make_empty_dir_inode(inode);
<------>inode->i_flags |= S_AUTOMOUNT;
<------>inode->i_private = data;
<------>dentry->d_fsdata = (void *)f;
<------>/* directory inodes start off with i_nlink == 2 (for "." entry) */
<------>inc_nlink(inode);
<------>d_instantiate(dentry, inode);
<------>inc_nlink(d_inode(dentry->d_parent));
<------>fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
<------>return end_creating(dentry);
}
EXPORT_SYMBOL(debugfs_create_automount);
 
/**
 * 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 parameter 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, ERR_PTR(-ERROR)
 * 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 *dentry;
<------>struct inode *inode;
<------>char *link = kstrdup(target, GFP_KERNEL);
<------>if (!link)
<------><------>return ERR_PTR(-ENOMEM);
 
<------>dentry = start_creating(name, parent);
<------>if (IS_ERR(dentry)) {
<------><------>kfree(link);
<------><------>return dentry;
<------>}
 
<------>inode = debugfs_get_inode(dentry->d_sb);
<------>if (unlikely(!inode)) {
<------><------>pr_err("out of free dentries, can not create symlink '%s'\n",
<------><------>       name);
<------><------>kfree(link);
<------><------>return failed_creating(dentry);
<------>}
<------>inode->i_mode = S_IFLNK | S_IRWXUGO;
<------>inode->i_op = &debugfs_symlink_inode_operations;
<------>inode->i_link = link;
<------>d_instantiate(dentry, inode);
<------>return end_creating(dentry);
}
EXPORT_SYMBOL_GPL(debugfs_create_symlink);
 
static void __debugfs_file_removed(struct dentry *dentry)
{
<------>struct debugfs_fsdata *fsd;
 
<------>/*
<------> * Paired with the closing smp_mb() implied by a successful
<------> * cmpxchg() in debugfs_file_get(): either
<------> * debugfs_file_get() must see a dead dentry or we must see a
<------> * debugfs_fsdata instance at ->d_fsdata here (or both).
<------> */
<------>smp_mb();
<------>fsd = READ_ONCE(dentry->d_fsdata);
<------>if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)
<------><------>return;
<------>if (!refcount_dec_and_test(&fsd->active_users))
<------><------>wait_for_completion(&fsd->active_users_drained);
}
 
static void remove_one(struct dentry *victim)
{
        if (d_is_reg(victim))
<------><------>__debugfs_file_removed(victim);
<------>simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}
 
/**
 * debugfs_remove - recursively removes a directory
 * @dentry: a pointer to a the dentry of the directory to be removed.  If this
 *          parameter is NULL or an error value, nothing will be done.
 *
 * 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(struct dentry *dentry)
{
<------>if (IS_ERR_OR_NULL(dentry))
<------><------>return;
 
<------>simple_pin_fs(&debug_fs_type, &debugfs_mount, &debugfs_mount_count);
<------>simple_recursive_removal(dentry, remove_one);
<------>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;
<------>struct name_snapshot old_name;
 
<------>if (IS_ERR(old_dir))
<------><------>return old_dir;
<------>if (IS_ERR(new_dir))
<------><------>return new_dir;
<------>if (IS_ERR_OR_NULL(old_dentry))
<------><------>return old_dentry;
 
<------>trap = lock_rename(new_dir, old_dir);
<------>/* Source or destination directories don't exist? */
<------>if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir))
<------><------>goto exit;
<------>/* Source does not exist, cyclic rename, or mountpoint? */
<------>if (d_really_is_negative(old_dentry) || 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 || d_really_is_positive(dentry))
<------><------>goto exit;
 
<------>take_dentry_name_snapshot(&old_name, old_dentry);
 
<------>error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir),
<------><------><------>      dentry, 0);
<------>if (error) {
<------><------>release_dentry_name_snapshot(&old_name);
<------><------>goto exit;
<------>}
<------>d_move(old_dentry, dentry);
<------>fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name,
<------><------>d_is_dir(old_dentry),
<------><------>NULL, old_dentry);
<------>release_dentry_name_snapshot(&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);
<------>if (IS_ERR(dentry))
<------><------>return dentry;
<------>return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL_GPL(debugfs_rename);
 
/**
 * debugfs_initialized - Tells whether debugfs has been registered
 */
bool debugfs_initialized(void)
{
<------>return debugfs_registered;
}
EXPORT_SYMBOL_GPL(debugfs_initialized);
 
static int __init debugfs_kernel(char *str)
{
<------>if (str) {
<------><------>if (!strcmp(str, "on"))
<------><------><------>debugfs_allow = DEBUGFS_ALLOW_API | DEBUGFS_ALLOW_MOUNT;
<------><------>else if (!strcmp(str, "no-mount"))
<------><------><------>debugfs_allow = DEBUGFS_ALLOW_API;
<------><------>else if (!strcmp(str, "off"))
<------><------><------>debugfs_allow = 0;
<------>}
 
<------>return 0;
}
early_param("debugfs", debugfs_kernel);
static int __init debugfs_init(void)
{
<------>int retval;
 
<------>if (!(debugfs_allow & DEBUGFS_ALLOW_MOUNT))
<------><------>return -EPERM;
 
<------>retval = sysfs_create_mount_point(kernel_kobj, "debug");
<------>if (retval)
<------><------>return retval;
 
<------>retval = register_filesystem(&debug_fs_type);
<------>if (retval)
<------><------>sysfs_remove_mount_point(kernel_kobj, "debug");
<------>else
<------><------>debugfs_registered = true;
 
<------>return retval;
}
core_initcall(debugfs_init);