689 lines
18 KiB
C
689 lines
18 KiB
C
/*
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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 Greg Kroah-Hartman <greg@kroah.com>
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* Copyright (C) 2004 IBM Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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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/DocBook/kernel-api for more details.
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*
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*/
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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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#define DEBUGFS_DEFAULT_MODE 0755
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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 struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev_t dev,
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void *data, const struct file_operations *fops)
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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_mode = mode;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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switch (mode & S_IFMT) {
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default:
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init_special_inode(inode, mode, dev);
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break;
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case S_IFREG:
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inode->i_fop = fops ? fops : &debugfs_file_operations;
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inode->i_private = data;
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break;
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case S_IFLNK:
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inode->i_op = &debugfs_link_operations;
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inode->i_private = data;
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break;
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case S_IFDIR:
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inode->i_op = &simple_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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inode->i_private = NULL;
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/* directory inodes start off with i_nlink == 2
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* (for "." entry) */
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inc_nlink(inode);
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break;
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}
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}
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return inode;
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}
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/* SMP-safe */
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static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
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umode_t mode, dev_t dev, void *data,
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const struct file_operations *fops)
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{
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struct inode *inode;
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int error = -EPERM;
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if (dentry->d_inode)
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return -EEXIST;
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inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
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if (inode) {
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d_instantiate(dentry, inode);
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dget(dentry);
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error = 0;
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}
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return error;
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}
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static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
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{
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int res;
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mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
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res = debugfs_mknod(dir, dentry, mode, 0, NULL, NULL);
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if (!res) {
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inc_nlink(dir);
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fsnotify_mkdir(dir, dentry);
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}
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return res;
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}
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static int debugfs_link(struct inode *dir, struct dentry *dentry, umode_t mode,
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void *data)
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{
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mode = (mode & S_IALLUGO) | S_IFLNK;
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return debugfs_mknod(dir, dentry, mode, 0, data, NULL);
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}
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static int debugfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
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void *data, const struct file_operations *fops)
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{
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int res;
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mode = (mode & S_IALLUGO) | S_IFREG;
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res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
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if (!res)
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fsnotify_create(dir, dentry);
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return res;
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}
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static inline int debugfs_positive(struct dentry *dentry)
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{
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return dentry->d_inode && !d_unhashed(dentry);
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}
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struct debugfs_mount_opts {
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uid_t uid;
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gid_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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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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opts->uid = option;
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break;
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case Opt_gid:
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if (match_octal(&args[0], &option))
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return -EINVAL;
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opts->gid = option;
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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 = sb->s_root->d_inode;
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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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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 (opts->uid != 0)
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seq_printf(m, ",uid=%u", opts->uid);
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if (opts->gid != 0)
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seq_printf(m, ",gid=%u", 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 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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};
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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 struct tree_descr debug_files[] = {{""}};
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struct debugfs_fs_info *fsi;
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int err;
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save_mount_options(sb, data);
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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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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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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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struct dentry *__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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struct dentry *dentry = NULL;
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int error;
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pr_debug("debugfs: creating file '%s'\n",name);
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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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goto exit;
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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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dentry = NULL;
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mutex_lock(&parent->d_inode->i_mutex);
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dentry = lookup_one_len(name, parent, strlen(name));
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if (!IS_ERR(dentry)) {
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switch (mode & S_IFMT) {
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case S_IFDIR:
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error = debugfs_mkdir(parent->d_inode, dentry, mode);
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break;
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case S_IFLNK:
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error = debugfs_link(parent->d_inode, dentry, mode,
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data);
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break;
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default:
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error = debugfs_create(parent->d_inode, dentry, mode,
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data, fops);
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break;
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}
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dput(dentry);
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} else
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error = PTR_ERR(dentry);
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mutex_unlock(&parent->d_inode->i_mutex);
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if (error) {
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dentry = NULL;
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simple_release_fs(&debugfs_mount, &debugfs_mount_count);
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}
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exit:
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return 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 paramater 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, %NULL will be 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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switch (mode & S_IFMT) {
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case S_IFREG:
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case 0:
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break;
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default:
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BUG();
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}
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return __create_file(name, mode, parent, data, 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_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 paramater 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, %NULL will be 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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return __create_file(name, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
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parent, NULL, NULL);
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}
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EXPORT_SYMBOL_GPL(debugfs_create_dir);
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/**
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* debugfs_create_symlink- create a symbolic link in the debugfs filesystem
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* @name: a pointer to a string containing the name of the symbolic link to
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* create.
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* @parent: a pointer to the parent dentry for this symbolic link. This
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* should be a directory dentry if set. If this paramater is NULL,
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* then the symbolic link will be created in the root of the debugfs
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* filesystem.
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* @target: a pointer to a string containing the path to the target of the
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* symbolic link.
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*
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* This function creates a symbolic link with the given name in debugfs that
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* links to the given target path.
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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 symbolic
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* link is to be removed (no automatic cleanup happens if your module is
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* unloaded, you are responsible here.) If an error occurs, %NULL 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_symlink(const char *name, struct dentry *parent,
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const char *target)
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{
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struct dentry *result;
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char *link;
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link = kstrdup(target, GFP_KERNEL);
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if (!link)
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return NULL;
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result = __create_file(name, S_IFLNK | S_IRWXUGO, parent, link, NULL);
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if (!result)
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kfree(link);
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return result;
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}
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EXPORT_SYMBOL_GPL(debugfs_create_symlink);
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static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
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{
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int ret = 0;
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if (debugfs_positive(dentry)) {
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if (dentry->d_inode) {
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dget(dentry);
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switch (dentry->d_inode->i_mode & S_IFMT) {
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case S_IFDIR:
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ret = simple_rmdir(parent->d_inode, dentry);
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break;
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case S_IFLNK:
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kfree(dentry->d_inode->i_private);
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/* fall through */
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default:
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simple_unlink(parent->d_inode, dentry);
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break;
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}
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if (!ret)
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d_delete(dentry);
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dput(dentry);
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}
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}
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return ret;
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}
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/**
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* debugfs_remove - removes a file or directory from the debugfs filesystem
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* @dentry: a pointer to a the dentry of the file or directory to be
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* removed.
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*
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* This function removes a file or directory in debugfs that was previously
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* created with a call to another debugfs function (like
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* debugfs_create_file() or variants thereof.)
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*
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* This function is required to be called in order for the file to be
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* removed, no automatic cleanup of files will happen when a module is
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* removed, you are responsible here.
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*/
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void debugfs_remove(struct dentry *dentry)
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{
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struct dentry *parent;
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int ret;
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if (IS_ERR_OR_NULL(dentry))
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return;
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parent = dentry->d_parent;
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if (!parent || !parent->d_inode)
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return;
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mutex_lock(&parent->d_inode->i_mutex);
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ret = __debugfs_remove(dentry, parent);
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mutex_unlock(&parent->d_inode->i_mutex);
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if (!ret)
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simple_release_fs(&debugfs_mount, &debugfs_mount_count);
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}
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EXPORT_SYMBOL_GPL(debugfs_remove);
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/**
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* debugfs_remove_recursive - recursively removes a directory
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* @dentry: a pointer to a the dentry of the directory to be removed.
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*
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* This function recursively removes a directory tree in debugfs that
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* was previously created with a call to another debugfs function
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* (like debugfs_create_file() or variants thereof.)
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*
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* This function is required to be called in order for the file to be
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* removed, no automatic cleanup of files will happen when a module is
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* removed, you are responsible here.
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*/
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void debugfs_remove_recursive(struct dentry *dentry)
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{
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struct dentry *child;
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struct dentry *parent;
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if (IS_ERR_OR_NULL(dentry))
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return;
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parent = dentry->d_parent;
|
|
if (!parent || !parent->d_inode)
|
|
return;
|
|
|
|
parent = dentry;
|
|
mutex_lock(&parent->d_inode->i_mutex);
|
|
|
|
while (1) {
|
|
/*
|
|
* When all dentries under "parent" has been removed,
|
|
* walk up the tree until we reach our starting point.
|
|
*/
|
|
if (list_empty(&parent->d_subdirs)) {
|
|
mutex_unlock(&parent->d_inode->i_mutex);
|
|
if (parent == dentry)
|
|
break;
|
|
parent = parent->d_parent;
|
|
mutex_lock(&parent->d_inode->i_mutex);
|
|
}
|
|
child = list_entry(parent->d_subdirs.next, struct dentry,
|
|
d_u.d_child);
|
|
next_sibling:
|
|
|
|
/*
|
|
* If "child" isn't empty, walk down the tree and
|
|
* remove all its descendants first.
|
|
*/
|
|
if (!list_empty(&child->d_subdirs)) {
|
|
mutex_unlock(&parent->d_inode->i_mutex);
|
|
parent = child;
|
|
mutex_lock(&parent->d_inode->i_mutex);
|
|
continue;
|
|
}
|
|
__debugfs_remove(child, parent);
|
|
if (parent->d_subdirs.next == &child->d_u.d_child) {
|
|
/*
|
|
* Try the next sibling.
|
|
*/
|
|
if (child->d_u.d_child.next != &parent->d_subdirs) {
|
|
child = list_entry(child->d_u.d_child.next,
|
|
struct dentry,
|
|
d_u.d_child);
|
|
goto next_sibling;
|
|
}
|
|
|
|
/*
|
|
* Avoid infinite loop if we fail to remove
|
|
* one dentry.
|
|
*/
|
|
mutex_unlock(&parent->d_inode->i_mutex);
|
|
break;
|
|
}
|
|
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
|
|
}
|
|
|
|
parent = dentry->d_parent;
|
|
mutex_lock(&parent->d_inode->i_mutex);
|
|
__debugfs_remove(dentry, parent);
|
|
mutex_unlock(&parent->d_inode->i_mutex);
|
|
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
|
|
}
|
|
EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
|
|
|
|
/**
|
|
* debugfs_rename - rename a file/directory in the debugfs filesystem
|
|
* @old_dir: a pointer to the parent dentry for the renamed object. This
|
|
* should be a directory dentry.
|
|
* @old_dentry: dentry of an object to be renamed.
|
|
* @new_dir: a pointer to the parent dentry where the object should be
|
|
* moved. This should be a directory dentry.
|
|
* @new_name: a pointer to a string containing the target name.
|
|
*
|
|
* This function renames a file/directory in debugfs. The target must not
|
|
* exist for rename to succeed.
|
|
*
|
|
* This function will return a pointer to old_dentry (which is updated to
|
|
* reflect renaming) if it succeeds. If an error occurs, %NULL will be
|
|
* returned.
|
|
*
|
|
* If debugfs is not enabled in the kernel, the value -%ENODEV will be
|
|
* returned.
|
|
*/
|
|
struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
|
|
struct dentry *new_dir, const char *new_name)
|
|
{
|
|
int error;
|
|
struct dentry *dentry = NULL, *trap;
|
|
const char *old_name;
|
|
|
|
trap = lock_rename(new_dir, old_dir);
|
|
/* Source or destination directories don't exist? */
|
|
if (!old_dir->d_inode || !new_dir->d_inode)
|
|
goto exit;
|
|
/* Source does not exist, cyclic rename, or mountpoint? */
|
|
if (!old_dentry->d_inode || old_dentry == trap ||
|
|
d_mountpoint(old_dentry))
|
|
goto exit;
|
|
dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
|
|
/* Lookup failed, cyclic rename or target exists? */
|
|
if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
|
|
goto exit;
|
|
|
|
old_name = fsnotify_oldname_init(old_dentry->d_name.name);
|
|
|
|
error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
|
|
dentry);
|
|
if (error) {
|
|
fsnotify_oldname_free(old_name);
|
|
goto exit;
|
|
}
|
|
d_move(old_dentry, dentry);
|
|
fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
|
|
S_ISDIR(old_dentry->d_inode->i_mode),
|
|
NULL, old_dentry);
|
|
fsnotify_oldname_free(old_name);
|
|
unlock_rename(new_dir, old_dir);
|
|
dput(dentry);
|
|
return old_dentry;
|
|
exit:
|
|
if (dentry && !IS_ERR(dentry))
|
|
dput(dentry);
|
|
unlock_rename(new_dir, old_dir);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(debugfs_rename);
|
|
|
|
/**
|
|
* debugfs_initialized - Tells whether debugfs has been registered
|
|
*/
|
|
bool debugfs_initialized(void)
|
|
{
|
|
return debugfs_registered;
|
|
}
|
|
EXPORT_SYMBOL_GPL(debugfs_initialized);
|
|
|
|
|
|
static struct kobject *debug_kobj;
|
|
|
|
static int __init debugfs_init(void)
|
|
{
|
|
int retval;
|
|
|
|
debug_kobj = kobject_create_and_add("debug", kernel_kobj);
|
|
if (!debug_kobj)
|
|
return -EINVAL;
|
|
|
|
retval = register_filesystem(&debug_fs_type);
|
|
if (retval)
|
|
kobject_put(debug_kobj);
|
|
else
|
|
debugfs_registered = true;
|
|
|
|
return retval;
|
|
}
|
|
core_initcall(debugfs_init);
|
|
|