[linux.git] / fs / hfsplus / wrapper.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/hfsplus/wrapper.c
 *
 * Copyright (C) 2001
 * Brad Boyer ([email protected])
 * (C) 2003 Ardis Technologies <[email protected]>
 *
 * Handling of HFS wrappers around HFS+ volumes
 */

#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/cdrom.h>
#include <linux/genhd.h>
#include <asm/unaligned.h>

#include "hfsplus_fs.h"
#include "hfsplus_raw.h"

struct hfsplus_wd {
	u32 ablk_size;
	u16 ablk_start;
	u16 embed_start;
	u16 embed_count;
};

/**
 * hfsplus_submit_bio - Perform block I/O
 * @sb: super block of volume for I/O
 * @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes
 * @buf: buffer for I/O
 * @data: output pointer for location of requested data
 * @op: direction of I/O
 * @op_flags: request op flags
 *
 * The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than
 * HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads
 * @data will return a pointer to the start of the requested sector,
 * which may not be the same location as @buf.
 *
 * If @sector is not aligned to the bdev logical block size it will
 * be rounded down. For writes this means that @buf should contain data
 * that starts at the rounded-down address. As long as the data was
 * read using hfsplus_submit_bio() and the same buffer is used things
 * will work correctly.
 */
int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
		       void *buf, void **data, int op, int op_flags)
{
	struct bio *bio;
	int ret = 0;
	u64 io_size;
	loff_t start;
	int offset;

	/*
	 * Align sector to hardware sector size and find offset. We
	 * assume that io_size is a power of two, which _should_
	 * be true.
	 */
	io_size = hfsplus_min_io_size(sb);
	start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;
	offset = start & (io_size - 1);
	sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);

	bio = bio_alloc(GFP_NOIO, 1);
	bio->bi_iter.bi_sector = sector;
	bio_set_dev(bio, sb->s_bdev);
	bio_set_op_attrs(bio, op, op_flags);

	if (op != WRITE && data)
		*data = (u8 *)buf + offset;

	while (io_size > 0) {
		unsigned int page_offset = offset_in_page(buf);
		unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset,
					 io_size);

		ret = bio_add_page(bio, virt_to_page(buf), len, page_offset);
		if (ret != len) {
			ret = -EIO;
			goto out;
		}
		io_size -= len;
		buf = (u8 *)buf + len;
	}

	ret = submit_bio_wait(bio);
out:
	bio_put(bio);
	return ret < 0 ? ret : 0;
}

static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
{
	u32 extent;
	u16 attrib;
	__be16 sig;

	sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG);
	if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
	    sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
		return 0;

	attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB));
	if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) ||
	   !(attrib & HFSP_WRAP_ATTRIB_SPARED))
		return 0;

	wd->ablk_size =
		be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE));
	if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
		return 0;
	if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
		return 0;
	wd->ablk_start =
		be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART));

	extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
	wd->embed_start = (extent >> 16) & 0xFFFF;
	wd->embed_count = extent & 0xFFFF;

	return 1;
}

static int hfsplus_get_last_session(struct super_block *sb,
				    sector_t *start, sector_t *size)
{
	struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);

	/* default values */
	*start = 0;
	*size = i_size_read(sb->s_bdev->bd_inode) >> 9;

	if (HFSPLUS_SB(sb)->session >= 0) {
		struct cdrom_tocentry te;

		if (!cdi)
			return -EINVAL;

		te.cdte_track = HFSPLUS_SB(sb)->session;
		te.cdte_format = CDROM_LBA;
		if (cdrom_read_tocentry(cdi, &te) ||
		    (te.cdte_ctrl & CDROM_DATA_TRACK) != 4) {
			pr_err("invalid session number or type of track\n");
			return -EINVAL;
		}
		*start = (sector_t)te.cdte_addr.lba << 2;
	} else if (cdi) {
		struct cdrom_multisession ms_info;

		ms_info.addr_format = CDROM_LBA;
		if (cdrom_multisession(cdi, &ms_info) == 0 && ms_info.xa_flag)
			*start = (sector_t)ms_info.addr.lba << 2;
	}

	return 0;
}

/* Find the volume header and fill in some minimum bits in superblock */
/* Takes in super block, returns true if good data read */
int hfsplus_read_wrapper(struct super_block *sb)
{
	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
	struct hfsplus_wd wd;
	sector_t part_start, part_size;
	u32 blocksize;
	int error = 0;

	error = -EINVAL;
	blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
	if (!blocksize)
		goto out;

	if (hfsplus_get_last_session(sb, &part_start, &part_size))
		goto out;

	error = -ENOMEM;
	sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
	if (!sbi->s_vhdr_buf)
		goto out;
	sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
	if (!sbi->s_backup_vhdr_buf)
		goto out_free_vhdr;

reread:
	error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
				   sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
				   REQ_OP_READ, 0);
	if (error)
		goto out_free_backup_vhdr;

	error = -EINVAL;
	switch (sbi->s_vhdr->signature) {
	case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX):
		set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
		fallthrough;
	case cpu_to_be16(HFSPLUS_VOLHEAD_SIG):
		break;
	case cpu_to_be16(HFSP_WRAP_MAGIC):
		if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
			goto out_free_backup_vhdr;
		wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
		part_start += (sector_t)wd.ablk_start +
			       (sector_t)wd.embed_start * wd.ablk_size;
		part_size = (sector_t)wd.embed_count * wd.ablk_size;
		goto reread;
	default:
		/*
		 * Check for a partition block.
		 *
		 * (should do this only for cdrom/loop though)
		 */
		if (hfs_part_find(sb, &part_start, &part_size))
			goto out_free_backup_vhdr;
		goto reread;
	}

	error = hfsplus_submit_bio(sb, part_start + part_size - 2,
				   sbi->s_backup_vhdr_buf,
				   (void **)&sbi->s_backup_vhdr, REQ_OP_READ,
				   0);
	if (error)
		goto out_free_backup_vhdr;

	error = -EINVAL;
	if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) {
		pr_warn("invalid secondary volume header\n");
		goto out_free_backup_vhdr;
	}

	blocksize = be32_to_cpu(sbi->s_vhdr->blocksize);

	/*
	 * Block size must be at least as large as a sector and a multiple of 2.
	 */
	if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize))
		goto out_free_backup_vhdr;
	sbi->alloc_blksz = blocksize;
	sbi->alloc_blksz_shift = ilog2(blocksize);
	blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE);

	/*
	 * Align block size to block offset.
	 */
	while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
		blocksize >>= 1;

	if (sb_set_blocksize(sb, blocksize) != blocksize) {
		pr_err("unable to set blocksize to %u!\n", blocksize);
		goto out_free_backup_vhdr;
	}

	sbi->blockoffset =
		part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
	sbi->part_start = part_start;
	sbi->sect_count = part_size;
	sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
	return 0;

out_free_backup_vhdr:
	kfree(sbi->s_backup_vhdr_buf);
out_free_vhdr:
	kfree(sbi->s_vhdr_buf);
out:
	return error;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/hfsplus/wrapper.c
	4	*
	5	* Copyright (C) 2001
	6	* Brad Boyer ([email protected])
	7	* (C) 2003 Ardis Technologies <[email protected]>
	8	*
	9	* Handling of HFS wrappers around HFS+ volumes
	10	*/
	11
	12	#include <linux/fs.h>
	13	#include <linux/blkdev.h>
	14	#include <linux/cdrom.h>
	15	#include <linux/genhd.h>
1da177e4 LT	16	#include <asm/unaligned.h>
	17
	18	#include "hfsplus_fs.h"
	19	#include "hfsplus_raw.h"
	20
	21	struct hfsplus_wd {
	22	u32 ablk_size;
	23	u16 ablk_start;
	24	u16 embed_start;
	25	u16 embed_count;
	26	};
	27
915ab236 FF	28	/**
915ab236 FF	29	* hfsplus_submit_bio - Perform block I/O
6596528e SF	30	* @sb: super block of volume for I/O
	31	* @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes
	32	* @buf: buffer for I/O
	33	* @data: output pointer for location of requested data
67ed2596 MC	34	* @op: direction of I/O
67ed2596 MC	35	* @op_flags: request op flags
6596528e SF	36	*
	37	* The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than
	38	* HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads
	39	* @data will return a pointer to the start of the requested sector,
	40	* which may not be the same location as @buf.
	41	*
	42	* If @sector is not aligned to the bdev logical block size it will
	43	* be rounded down. For writes this means that @buf should contain data
	44	* that starts at the rounded-down address. As long as the data was
	45	* read using hfsplus_submit_bio() and the same buffer is used things
	46	* will work correctly.
	47	*/
	48	int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
67ed2596	49	void buf, void *data, int op, int op_flags)
52399b17	50	{
52399b17	51	struct bio *bio;
50176dde	52	int ret = 0;
a6dc8c04	53	u64 io_size;
6596528e SF	54	loff_t start;
	55	int offset;
	56
	57	/*
	58	* Align sector to hardware sector size and find offset. We
	59	* assume that io_size is a power of two, which _should_
	60	* be true.
	61	*/
	62	io_size = hfsplus_min_io_size(sb);
	63	start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;
	64	offset = start & (io_size - 1);
	65	sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);
52399b17 CH	66
52399b17 CH	67	bio = bio_alloc(GFP_NOIO, 1);
4f024f37	68	bio->bi_iter.bi_sector = sector;
74d46992	69	bio_set_dev(bio, sb->s_bdev);
67ed2596	70	bio_set_op_attrs(bio, op, op_flags);
52399b17	71
67ed2596	72	if (op != WRITE && data)
6596528e SF	73	data = (u8 )buf + offset;
	74
	75	while (io_size > 0) {
	76	unsigned int page_offset = offset_in_page(buf);
	77	unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset,
	78	io_size);
	79
	80	ret = bio_add_page(bio, virt_to_page(buf), len, page_offset);
	81	if (ret != len) {
	82	ret = -EIO;
	83	goto out;
	84	}
	85	io_size -= len;
	86	buf = (u8 *)buf + len;
	87	}
52399b17	88
4e49ea4a	89	ret = submit_bio_wait(bio);
6596528e	90	out:
50176dde	91	bio_put(bio);
6596528e	92	return ret < 0 ? ret : 0;
52399b17 CH	93	}
52399b17 CH	94
1da177e4 LT	95	static int hfsplus_read_mdb(void bufptr, struct hfsplus_wd wd)
	96	{
	97	u32 extent;
	98	u16 attrib;
2179d372	99	__be16 sig;
1da177e4	100
2179d372 DE	101	sig = (__be16 )(bufptr + HFSP_WRAPOFF_EMBEDSIG);
	102	if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
	103	sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
1da177e4 LT	104	return 0;
	105
	106	attrib = be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_ATTRIB));
	107	if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) \|\|
	108	!(attrib & HFSP_WRAP_ATTRIB_SPARED))
	109	return 0;
	110
2753cc28 AS	111	wd->ablk_size =
2753cc28 AS	112	be32_to_cpu((__be32 )(bufptr + HFSP_WRAPOFF_ABLKSIZE));
1da177e4 LT	113	if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
	114	return 0;
	115	if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
	116	return 0;
2753cc28 AS	117	wd->ablk_start =
2753cc28 AS	118	be16_to_cpu((__be16 )(bufptr + HFSP_WRAPOFF_ABLKSTART));
1da177e4	119
8b3789e5	120	extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
1da177e4 LT	121	wd->embed_start = (extent >> 16) & 0xFFFF;
	122	wd->embed_count = extent & 0xFFFF;
	123
	124	return 1;
	125	}
	126
	127	static int hfsplus_get_last_session(struct super_block *sb,
	128	sector_t start, sector_t size)
	129	{
f252fa33	130	struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);
1da177e4 LT	131
	132	/* default values */
	133	*start = 0;
a3f22350	134	*size = i_size_read(sb->s_bdev->bd_inode) >> 9;
1da177e4	135
dd73a01a	136	if (HFSPLUS_SB(sb)->session >= 0) {
f252fa33 CH	137	struct cdrom_tocentry te;
	138
	139	if (!cdi)
	140	return -EINVAL;
	141
dd73a01a	142	te.cdte_track = HFSPLUS_SB(sb)->session;
1da177e4	143	te.cdte_format = CDROM_LBA;
f252fa33 CH	144	if (cdrom_read_tocentry(cdi, &te) \|\|
	145	(te.cdte_ctrl & CDROM_DATA_TRACK) != 4) {
	146	pr_err("invalid session number or type of track\n");
	147	return -EINVAL;
1da177e4	148	}
f252fa33 CH	149	*start = (sector_t)te.cdte_addr.lba << 2;
	150	} else if (cdi) {
	151	struct cdrom_multisession ms_info;
	152
	153	ms_info.addr_format = CDROM_LBA;
	154	if (cdrom_multisession(cdi, &ms_info) == 0 && ms_info.xa_flag)
	155	*start = (sector_t)ms_info.addr.lba << 2;
1da177e4	156	}
f252fa33	157
1da177e4 LT	158	return 0;
	159	}
	160
	161	/* Find the volume header and fill in some minimum bits in superblock */
	162	/* Takes in super block, returns true if good data read */
	163	int hfsplus_read_wrapper(struct super_block *sb)
	164	{
dd73a01a	165	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
1da177e4 LT	166	struct hfsplus_wd wd;
	167	sector_t part_start, part_size;
	168	u32 blocksize;
52399b17	169	int error = 0;
1da177e4	170
52399b17	171	error = -EINVAL;
1da177e4 LT	172	blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
1da177e4 LT	173	if (!blocksize)
52399b17	174	goto out;
1da177e4 LT	175
1da177e4 LT	176	if (hfsplus_get_last_session(sb, &part_start, &part_size))
52399b17	177	goto out;
1da177e4	178
52399b17	179	error = -ENOMEM;
6596528e SF	180	sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
6596528e SF	181	if (!sbi->s_vhdr_buf)
52399b17	182	goto out;
6596528e SF	183	sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
6596528e SF	184	if (!sbi->s_backup_vhdr_buf)
52399b17 CH	185	goto out_free_vhdr;
	186
	187	reread:
6596528e SF	188	error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
6596528e SF	189	sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
67ed2596	190	REQ_OP_READ, 0);
52399b17 CH	191	if (error)
	192	goto out_free_backup_vhdr;
	193
	194	error = -EINVAL;
	195	switch (sbi->s_vhdr->signature) {
	196	case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX):
	197	set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
df561f66	198	fallthrough;
52399b17 CH	199	case cpu_to_be16(HFSPLUS_VOLHEAD_SIG):
	200	break;
	201	case cpu_to_be16(HFSP_WRAP_MAGIC):
	202	if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
a1dbcef0	203	goto out_free_backup_vhdr;
52399b17	204	wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
4ba2d5fd CH	205	part_start += (sector_t)wd.ablk_start +
	206	(sector_t)wd.embed_start * wd.ablk_size;
	207	part_size = (sector_t)wd.embed_count * wd.ablk_size;
52399b17 CH	208	goto reread;
	209	default:
	210	/*
	211	* Check for a partition block.
	212	*
1da177e4 LT	213	* (should do this only for cdrom/loop though)
	214	*/
	215	if (hfs_part_find(sb, &part_start, &part_size))
a1dbcef0	216	goto out_free_backup_vhdr;
52399b17 CH	217	goto reread;
	218	}
	219
6596528e SF	220	error = hfsplus_submit_bio(sb, part_start + part_size - 2,
6596528e SF	221	sbi->s_backup_vhdr_buf,
67ed2596 MC	222	(void **)&sbi->s_backup_vhdr, REQ_OP_READ,
67ed2596 MC	223	0);
52399b17 CH	224	if (error)
	225	goto out_free_backup_vhdr;
	226
	227	error = -EINVAL;
	228	if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) {
d6142673	229	pr_warn("invalid secondary volume header\n");
52399b17	230	goto out_free_backup_vhdr;
1da177e4 LT	231	}
1da177e4 LT	232
52399b17	233	blocksize = be32_to_cpu(sbi->s_vhdr->blocksize);
1da177e4	234
52399b17 CH	235	/*
52399b17 CH	236	* Block size must be at least as large as a sector and a multiple of 2.
1da177e4	237	*/
52399b17 CH	238	if (blocksize < HFSPLUS_SECTOR_SIZE \|\| ((blocksize - 1) & blocksize))
52399b17 CH	239	goto out_free_backup_vhdr;
dd73a01a	240	sbi->alloc_blksz = blocksize;
297cc272	241	sbi->alloc_blksz_shift = ilog2(blocksize);
915ab236	242	blocksize = min_t(u32, sbi->alloc_blksz, PAGE_SIZE);
1da177e4	243
52399b17 CH	244	/*
	245	* Align block size to block offset.
	246	*/
1da177e4 LT	247	while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
	248	blocksize >>= 1;
	249
	250	if (sb_set_blocksize(sb, blocksize) != blocksize) {
d6142673	251	pr_err("unable to set blocksize to %u!\n", blocksize);
52399b17	252	goto out_free_backup_vhdr;
1da177e4 LT	253	}
1da177e4 LT	254
dd73a01a CH	255	sbi->blockoffset =
dd73a01a CH	256	part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
52399b17	257	sbi->part_start = part_start;
dd73a01a CH	258	sbi->sect_count = part_size;
dd73a01a CH	259	sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
1da177e4	260	return 0;
52399b17 CH	261
52399b17 CH	262	out_free_backup_vhdr:
f588c960	263	kfree(sbi->s_backup_vhdr_buf);
52399b17	264	out_free_vhdr:
f588c960	265	kfree(sbi->s_vhdr_buf);
52399b17 CH	266	out:
52399b17 CH	267	return error;
1da177e4	268	}