xref: /kernel/linux/linux-5.10/fs/hfsplus/ioctl.c (revision 8c2ecf20) 
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
60static inline unsigned int hfsplus_getflags(struct inode *inode)
61{
62	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
63	unsigned int flags = 0;
64
65	if (inode->i_flags & S_IMMUTABLE)
66		flags |= FS_IMMUTABLE_FL;
67	if (inode->i_flags & S_APPEND)
68		flags |= FS_APPEND_FL;
69	if (hip->userflags & HFSPLUS_FLG_NODUMP)
70		flags |= FS_NODUMP_FL;
71	return flags;
72}
73
74static int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)
75{
76	struct inode *inode = file_inode(file);
77	unsigned int flags = hfsplus_getflags(inode);
78
79	return put_user(flags, user_flags);
80}
81
82static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
83{
84	struct inode *inode = file_inode(file);
85	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
86	unsigned int flags, new_fl = 0;
87	unsigned int oldflags = hfsplus_getflags(inode);
88	int err = 0;
89
90	err = mnt_want_write_file(file);
91	if (err)
92		goto out;
93
94	if (!inode_owner_or_capable(inode)) {
95		err = -EACCES;
96		goto out_drop_write;
97	}
98
99	if (get_user(flags, user_flags)) {
100		err = -EFAULT;
101		goto out_drop_write;
102	}
103
104	inode_lock(inode);
105
106	err = vfs_ioc_setflags_prepare(inode, oldflags, flags);
107	if (err)
108		goto out_unlock_inode;
109
110	/* don't silently ignore unsupported ext2 flags */
111	if (flags & ~(FS_IMMUTABLE_FL|FS_APPEND_FL|FS_NODUMP_FL)) {
112		err = -EOPNOTSUPP;
113		goto out_unlock_inode;
114	}
115
116	if (flags & FS_IMMUTABLE_FL)
117		new_fl |= S_IMMUTABLE;
118
119	if (flags & FS_APPEND_FL)
120		new_fl |= S_APPEND;
121
122	inode_set_flags(inode, new_fl, S_IMMUTABLE | S_APPEND);
123
124	if (flags & FS_NODUMP_FL)
125		hip->userflags |= HFSPLUS_FLG_NODUMP;
126	else
127		hip->userflags &= ~HFSPLUS_FLG_NODUMP;
128
129	inode->i_ctime = current_time(inode);
130	mark_inode_dirty(inode);
131
132out_unlock_inode:
133	inode_unlock(inode);
134out_drop_write:
135	mnt_drop_write_file(file);
136out:
137	return err;
138}
139
140long hfsplus_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
141{
142	void __user *argp = (void __user *)arg;
143
144	switch (cmd) {
145	case HFSPLUS_IOC_EXT2_GETFLAGS:
146		return hfsplus_ioctl_getflags(file, argp);
147	case HFSPLUS_IOC_EXT2_SETFLAGS:
148		return hfsplus_ioctl_setflags(file, argp);
149	case HFSPLUS_IOC_BLESS:
150		return hfsplus_ioctl_bless(file, argp);
151	default:
152		return -ENOTTY;
153	}
154}
155