884 lines
26 KiB
C
884 lines
26 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* inode.c - part of debugfs, a tiny little debug file system
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*
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* Copyright (C) 2004,2019 Greg Kroah-Hartman <greg@kroah.com>
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* Copyright (C) 2004 IBM Inc.
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* Copyright (C) 2019 Linux Foundation <gregkh@linuxfoundation.org>
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*
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* debugfs is for people to use instead of /proc or /sys.
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* See ./Documentation/core-api/kernel-api.rst for more details.
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*/
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#define pr_fmt(fmt) "debugfs: " fmt
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/pagemap.h>
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#include <linux/init.h>
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#include <linux/kobject.h>
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#include <linux/namei.h>
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#include <linux/debugfs.h>
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#include <linux/fsnotify.h>
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#include <linux/string.h>
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#include <linux/seq_file.h>
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#include <linux/parser.h>
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#include <linux/magic.h>
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#include <linux/slab.h>
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#include <linux/security.h>
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#include "internal.h"
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#define DEBUGFS_DEFAULT_MODE 0700
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static struct vfsmount *debugfs_mount;
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static int debugfs_mount_count;
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static bool debugfs_registered;
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static unsigned int debugfs_allow __ro_after_init = DEFAULT_DEBUGFS_ALLOW_BITS;
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/*
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* Don't allow access attributes to be changed whilst the kernel is locked down
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* so that we can use the file mode as part of a heuristic to determine whether
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* to lock down individual files.
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*/
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static int debugfs_setattr(struct user_namespace *mnt_userns,
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struct dentry *dentry, struct iattr *ia)
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{
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int ret;
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if (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) {
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ret = security_locked_down(LOCKDOWN_DEBUGFS);
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if (ret)
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return ret;
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}
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return simple_setattr(&init_user_ns, dentry, ia);
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}
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static const struct inode_operations debugfs_file_inode_operations = {
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.setattr = debugfs_setattr,
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};
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static const struct inode_operations debugfs_dir_inode_operations = {
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.lookup = simple_lookup,
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.setattr = debugfs_setattr,
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};
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static const struct inode_operations debugfs_symlink_inode_operations = {
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.get_link = simple_get_link,
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.setattr = debugfs_setattr,
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};
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static struct inode *debugfs_get_inode(struct super_block *sb)
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{
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struct inode *inode = new_inode(sb);
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if (inode) {
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inode->i_ino = get_next_ino();
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inode->i_atime = inode->i_mtime =
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inode->i_ctime = current_time(inode);
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}
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return inode;
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}
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struct debugfs_mount_opts {
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kuid_t uid;
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kgid_t gid;
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umode_t mode;
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};
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enum {
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Opt_uid,
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Opt_gid,
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Opt_mode,
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Opt_err
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};
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static const match_table_t tokens = {
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{Opt_uid, "uid=%u"},
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{Opt_gid, "gid=%u"},
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{Opt_mode, "mode=%o"},
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{Opt_err, NULL}
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};
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struct debugfs_fs_info {
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struct debugfs_mount_opts mount_opts;
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};
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static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
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{
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substring_t args[MAX_OPT_ARGS];
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int option;
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int token;
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kuid_t uid;
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kgid_t gid;
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char *p;
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opts->mode = DEBUGFS_DEFAULT_MODE;
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while ((p = strsep(&data, ",")) != NULL) {
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if (!*p)
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continue;
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token = match_token(p, tokens, args);
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switch (token) {
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case Opt_uid:
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if (match_int(&args[0], &option))
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return -EINVAL;
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uid = make_kuid(current_user_ns(), option);
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if (!uid_valid(uid))
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return -EINVAL;
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opts->uid = uid;
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break;
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case Opt_gid:
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if (match_int(&args[0], &option))
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return -EINVAL;
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gid = make_kgid(current_user_ns(), option);
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if (!gid_valid(gid))
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return -EINVAL;
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opts->gid = gid;
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break;
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case Opt_mode:
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if (match_octal(&args[0], &option))
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return -EINVAL;
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opts->mode = option & S_IALLUGO;
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break;
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/*
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* We might like to report bad mount options here;
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* but traditionally debugfs has ignored all mount options
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*/
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}
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}
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return 0;
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}
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static int debugfs_apply_options(struct super_block *sb)
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{
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struct debugfs_fs_info *fsi = sb->s_fs_info;
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struct inode *inode = d_inode(sb->s_root);
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struct debugfs_mount_opts *opts = &fsi->mount_opts;
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inode->i_mode &= ~S_IALLUGO;
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inode->i_mode |= opts->mode;
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inode->i_uid = opts->uid;
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inode->i_gid = opts->gid;
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return 0;
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}
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static int debugfs_remount(struct super_block *sb, int *flags, char *data)
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{
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int err;
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struct debugfs_fs_info *fsi = sb->s_fs_info;
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sync_filesystem(sb);
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err = debugfs_parse_options(data, &fsi->mount_opts);
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if (err)
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goto fail;
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debugfs_apply_options(sb);
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fail:
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return err;
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}
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static int debugfs_show_options(struct seq_file *m, struct dentry *root)
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{
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struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
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struct debugfs_mount_opts *opts = &fsi->mount_opts;
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if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
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seq_printf(m, ",uid=%u",
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from_kuid_munged(&init_user_ns, opts->uid));
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if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
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seq_printf(m, ",gid=%u",
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from_kgid_munged(&init_user_ns, opts->gid));
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if (opts->mode != DEBUGFS_DEFAULT_MODE)
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seq_printf(m, ",mode=%o", opts->mode);
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return 0;
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}
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static void debugfs_free_inode(struct inode *inode)
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{
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if (S_ISLNK(inode->i_mode))
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kfree(inode->i_link);
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free_inode_nonrcu(inode);
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}
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static const struct super_operations debugfs_super_operations = {
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.statfs = simple_statfs,
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.remount_fs = debugfs_remount,
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.show_options = debugfs_show_options,
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.free_inode = debugfs_free_inode,
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};
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static void debugfs_release_dentry(struct dentry *dentry)
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{
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void *fsd = dentry->d_fsdata;
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if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))
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kfree(dentry->d_fsdata);
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}
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static struct vfsmount *debugfs_automount(struct path *path)
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{
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debugfs_automount_t f;
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f = (debugfs_automount_t)path->dentry->d_fsdata;
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return f(path->dentry, d_inode(path->dentry)->i_private);
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}
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static const struct dentry_operations debugfs_dops = {
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.d_delete = always_delete_dentry,
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.d_release = debugfs_release_dentry,
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.d_automount = debugfs_automount,
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};
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static int debug_fill_super(struct super_block *sb, void *data, int silent)
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{
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static const struct tree_descr debug_files[] = {{""}};
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struct debugfs_fs_info *fsi;
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int err;
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fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
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sb->s_fs_info = fsi;
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if (!fsi) {
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err = -ENOMEM;
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goto fail;
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}
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err = debugfs_parse_options(data, &fsi->mount_opts);
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if (err)
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goto fail;
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err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
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if (err)
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goto fail;
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sb->s_op = &debugfs_super_operations;
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sb->s_d_op = &debugfs_dops;
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debugfs_apply_options(sb);
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return 0;
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fail:
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kfree(fsi);
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sb->s_fs_info = NULL;
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return err;
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}
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static struct dentry *debug_mount(struct file_system_type *fs_type,
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int flags, const char *dev_name,
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void *data)
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{
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if (!(debugfs_allow & DEBUGFS_ALLOW_API))
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return ERR_PTR(-EPERM);
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return mount_single(fs_type, flags, data, debug_fill_super);
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}
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static struct file_system_type debug_fs_type = {
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.owner = THIS_MODULE,
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.name = "debugfs",
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.mount = debug_mount,
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.kill_sb = kill_litter_super,
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};
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MODULE_ALIAS_FS("debugfs");
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/**
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* debugfs_lookup() - look up an existing debugfs file
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* @name: a pointer to a string containing the name of the file to look up.
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* @parent: a pointer to the parent dentry of the file.
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*
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* This function will return a pointer to a dentry if it succeeds. If the file
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* doesn't exist or an error occurs, %NULL will be returned. The returned
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* dentry must be passed to dput() when it is no longer needed.
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*
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* If debugfs is not enabled in the kernel, the value -%ENODEV will be
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* returned.
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*/
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struct dentry *debugfs_lookup(const char *name, struct dentry *parent)
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{
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struct dentry *dentry;
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if (!debugfs_initialized() || IS_ERR_OR_NULL(name) || IS_ERR(parent))
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return NULL;
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if (!parent)
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parent = debugfs_mount->mnt_root;
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dentry = lookup_positive_unlocked(name, parent, strlen(name));
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if (IS_ERR(dentry))
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return NULL;
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return dentry;
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}
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EXPORT_SYMBOL_GPL(debugfs_lookup);
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static struct dentry *start_creating(const char *name, struct dentry *parent)
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{
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struct dentry *dentry;
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int error;
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if (!(debugfs_allow & DEBUGFS_ALLOW_API))
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return ERR_PTR(-EPERM);
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if (!debugfs_initialized())
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return ERR_PTR(-ENOENT);
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pr_debug("creating file '%s'\n", name);
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if (IS_ERR(parent))
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return parent;
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error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
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&debugfs_mount_count);
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if (error) {
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pr_err("Unable to pin filesystem for file '%s'\n", name);
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return ERR_PTR(error);
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}
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/* If the parent is not specified, we create it in the root.
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* We need the root dentry to do this, which is in the super
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* block. A pointer to that is in the struct vfsmount that we
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* have around.
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*/
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if (!parent)
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parent = debugfs_mount->mnt_root;
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inode_lock(d_inode(parent));
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if (unlikely(IS_DEADDIR(d_inode(parent))))
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dentry = ERR_PTR(-ENOENT);
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else
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dentry = lookup_one_len(name, parent, strlen(name));
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if (!IS_ERR(dentry) && d_really_is_positive(dentry)) {
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if (d_is_dir(dentry))
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pr_err("Directory '%s' with parent '%s' already present!\n",
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name, parent->d_name.name);
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else
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pr_err("File '%s' in directory '%s' already present!\n",
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name, parent->d_name.name);
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dput(dentry);
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dentry = ERR_PTR(-EEXIST);
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}
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if (IS_ERR(dentry)) {
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inode_unlock(d_inode(parent));
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simple_release_fs(&debugfs_mount, &debugfs_mount_count);
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}
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return dentry;
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}
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static struct dentry *failed_creating(struct dentry *dentry)
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{
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inode_unlock(d_inode(dentry->d_parent));
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dput(dentry);
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simple_release_fs(&debugfs_mount, &debugfs_mount_count);
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return ERR_PTR(-ENOMEM);
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}
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static struct dentry *end_creating(struct dentry *dentry)
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{
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inode_unlock(d_inode(dentry->d_parent));
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return dentry;
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}
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static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
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struct dentry *parent, void *data,
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const struct file_operations *proxy_fops,
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const struct file_operations *real_fops)
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{
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struct dentry *dentry;
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struct inode *inode;
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if (!(mode & S_IFMT))
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mode |= S_IFREG;
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BUG_ON(!S_ISREG(mode));
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dentry = start_creating(name, parent);
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if (IS_ERR(dentry))
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return dentry;
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if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
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failed_creating(dentry);
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return ERR_PTR(-EPERM);
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}
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inode = debugfs_get_inode(dentry->d_sb);
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if (unlikely(!inode)) {
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pr_err("out of free dentries, can not create file '%s'\n",
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name);
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return failed_creating(dentry);
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}
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inode->i_mode = mode;
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inode->i_private = data;
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inode->i_op = &debugfs_file_inode_operations;
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inode->i_fop = proxy_fops;
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dentry->d_fsdata = (void *)((unsigned long)real_fops |
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DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
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d_instantiate(dentry, inode);
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fsnotify_create(d_inode(dentry->d_parent), dentry);
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return end_creating(dentry);
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}
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/**
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* debugfs_create_file - create a file in the debugfs filesystem
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* @name: a pointer to a string containing the name of the file to create.
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* @mode: the permission that the file should have.
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* @parent: a pointer to the parent dentry for this file. This should be a
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* directory dentry if set. If this parameter is NULL, then the
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* file will be created in the root of the debugfs filesystem.
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* @data: a pointer to something that the caller will want to get to later
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* on. The inode.i_private pointer will point to this value on
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* the open() call.
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* @fops: a pointer to a struct file_operations that should be used for
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* this file.
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*
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* This is the basic "create a file" function for debugfs. It allows for a
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* wide range of flexibility in creating a file, or a directory (if you want
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* to create a directory, the debugfs_create_dir() function is
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* recommended to be used instead.)
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*
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* This function will return a pointer to a dentry if it succeeds. This
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* pointer must be passed to the debugfs_remove() function when the file is
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* to be removed (no automatic cleanup happens if your module is unloaded,
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* you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
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* returned.
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*
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* If debugfs is not enabled in the kernel, the value -%ENODEV will be
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* returned.
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*
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* NOTE: it's expected that most callers should _ignore_ the errors returned
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* by this function. Other debugfs functions handle the fact that the "dentry"
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* passed to them could be an error and they don't crash in that case.
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* Drivers should generally work fine even if debugfs fails to init anyway.
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*/
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struct dentry *debugfs_create_file(const char *name, umode_t mode,
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struct dentry *parent, void *data,
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const struct file_operations *fops)
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{
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return __debugfs_create_file(name, mode, parent, data,
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fops ? &debugfs_full_proxy_file_operations :
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&debugfs_noop_file_operations,
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fops);
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}
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EXPORT_SYMBOL_GPL(debugfs_create_file);
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/**
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* debugfs_create_file_unsafe - create a file in the debugfs filesystem
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* @name: a pointer to a string containing the name of the file to create.
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* @mode: the permission that the file should have.
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* @parent: a pointer to the parent dentry for this file. This should be a
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* directory dentry if set. If this parameter is NULL, then the
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* file will be created in the root of the debugfs filesystem.
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* @data: a pointer to something that the caller will want to get to later
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* on. The inode.i_private pointer will point to this value on
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* the open() call.
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* @fops: a pointer to a struct file_operations that should be used for
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* this file.
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*
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* debugfs_create_file_unsafe() is completely analogous to
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* debugfs_create_file(), the only difference being that the fops
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* handed it will not get protected against file removals by the
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* debugfs core.
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*
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* It is your responsibility to protect your struct file_operation
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* methods against file removals by means of debugfs_file_get()
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* and debugfs_file_put(). ->open() is still protected by
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* debugfs though.
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*
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* Any struct file_operations defined by means of
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* DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and
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* thus, may be used here.
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*/
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struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
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struct dentry *parent, void *data,
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const struct file_operations *fops)
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{
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return __debugfs_create_file(name, mode, parent, data,
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fops ? &debugfs_open_proxy_file_operations :
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&debugfs_noop_file_operations,
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fops);
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}
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EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe);
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/**
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* debugfs_create_file_size - create a file in the debugfs filesystem
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* @name: a pointer to a string containing the name of the file to create.
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* @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.
|
|
*
|
|
* NOTE: it's expected that most callers should _ignore_ the errors returned
|
|
* by this function. Other debugfs functions handle the fact that the "dentry"
|
|
* passed to them could be an error and they don't crash in that case.
|
|
* Drivers should generally work fine even if debugfs fails to init anyway.
|
|
*/
|
|
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_lookup_and_remove - lookup a directory or file and recursively remove it
|
|
* @name: a pointer to a string containing the name of the item to look up.
|
|
* @parent: a pointer to the parent dentry of the item.
|
|
*
|
|
* This is the equlivant of doing something like
|
|
* debugfs_remove(debugfs_lookup(..)) but with the proper reference counting
|
|
* handled for the directory being looked up.
|
|
*/
|
|
void debugfs_lookup_and_remove(const char *name, struct dentry *parent)
|
|
{
|
|
struct dentry *dentry;
|
|
|
|
dentry = debugfs_lookup(name, parent);
|
|
if (!dentry)
|
|
return;
|
|
|
|
debugfs_remove(dentry);
|
|
dput(dentry);
|
|
}
|
|
EXPORT_SYMBOL_GPL(debugfs_lookup_and_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(&init_user_ns, 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);
|