linux/fs/hfsplus/ioctl.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/hfsplus/ioctl.c
   4 *
   5 * Copyright (C) 2003
   6 * Ethan Benson <erbenson@alaska.net>
   7 * partially derived from linux/fs/ext2/ioctl.c
   8 * Copyright (C) 1993, 1994, 1995
   9 * Remy Card (card@masi.ibp.fr)
  10 * Laboratoire MASI - Institut Blaise Pascal
  11 * Universite Pierre et Marie Curie (Paris VI)
  12 *
  13 * hfsplus ioctls
  14 */
  15
  16#include <linux/capability.h>
  17#include <linux/fs.h>
  18#include <linux/mount.h>
  19#include <linux/sched.h>
  20#include <linux/uaccess.h>
  21#include "hfsplus_fs.h"
  22
  23/*
  24 * "Blessing" an HFS+ filesystem writes metadata to the superblock informing
  25 * the platform firmware which file to boot from
  26 */
  27static int hfsplus_ioctl_bless(struct file *file, int __user *user_flags)
  28{
  29        struct dentry *dentry = file->f_path.dentry;
  30        struct inode *inode = d_inode(dentry);
  31        struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);
  32        struct hfsplus_vh *vh = sbi->s_vhdr;
  33        struct hfsplus_vh *bvh = sbi->s_backup_vhdr;
  34        u32 cnid = (unsigned long)dentry->d_fsdata;
  35
  36        if (!capable(CAP_SYS_ADMIN))
  37                return -EPERM;
  38
  39        mutex_lock(&sbi->vh_mutex);
  40
  41        /* Directory containing the bootable system */
  42        vh->finder_info[0] = bvh->finder_info[0] =
  43                cpu_to_be32(parent_ino(dentry));
  44
  45        /*
  46         * Bootloader. Just using the inode here breaks in the case of
  47         * hard links - the firmware wants the ID of the hard link file,
  48         * but the inode points at the indirect inode
  49         */
  50        vh->finder_info[1] = bvh->finder_info[1] = cpu_to_be32(cnid);
  51
  52        /* Per spec, the OS X system folder - same as finder_info[0] here */
  53        vh->finder_info[5] = bvh->finder_info[5] =
  54                cpu_to_be32(parent_ino(dentry));
  55
  56        mutex_unlock(&sbi->vh_mutex);
  57        return 0;
  58}
  59
  60long hfsplus_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  61{
  62        void __user *argp = (void __user *)arg;
  63
  64        switch (cmd) {
  65        case HFSPLUS_IOC_BLESS:
  66                return hfsplus_ioctl_bless(file, argp);
  67        default:
  68                return -ENOTTY;
  69        }
  70}
  71