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851 lines
24 KiB
851 lines
24 KiB
// 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 <[email protected]> |
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* Copyright (C) 2004 IBM Inc. |
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* Copyright (C) 2019 Linux Foundation <[email protected]> |
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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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|
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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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/* |
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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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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. |
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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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* @file_size: initial file size |
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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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void debugfs_create_file_size(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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loff_t file_size) |
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{ |
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struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); |
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if (de) |
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d_inode(de)->i_size = file_size; |
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} |
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EXPORT_SYMBOL_GPL(debugfs_create_file_size); |
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|
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/** |
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* debugfs_create_dir - create a directory in the debugfs filesystem |
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* @name: a pointer to a string containing the name of the directory to |
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* create. |
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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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* directory will be created in the root of the debugfs filesystem. |
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* |
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* This function creates a directory in debugfs with the given name. |
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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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struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) |
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{ |
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struct dentry *dentry = start_creating(name, parent); |
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struct inode *inode; |
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|
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if (IS_ERR(dentry)) |
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return dentry; |
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|
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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); |
|
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(&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);
|
|
|