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