// SPDX-License-Identifier: GPL-2.0/* *  linux/fs/hfsplus/wrapper.c * * Copyright (C) 2001 * Brad Boyer (flar@allandria.com) * (C) 2003 Ardis Technologies <roman@ardistech.com> * * Handling of HFS wrappers around HFS+ volumes */ #include <linux/fs.h>#include <linux/blkdev.h>#include <linux/cdrom.h>#include <linux/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 * @opf: I/O operation type and 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. * * Returns: %0 on success else -errno code */int hfsplus_submit_bio(struct super_block *sb, sector_t sector,		       void *buf, void **data, blk_opf_t opf){	u64 io_size = hfsplus_min_io_size(sb);	loff_t start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;	int offset = start & (io_size - 1); 	if ((opf & REQ_OP_MASK) != REQ_OP_WRITE && data)		*data = (u8 *)buf + offset; 	/*	 * Align sector to hardware sector size and find offset. We assume that	 * io_size is a power of two, which _should_ be true.	 */	sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);	return bdev_rw_virt(sb->s_bdev, sector, buf, io_size, opf);} 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 = bdev_nr_sectors(sb->s_bdev); 	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; 	sbi->min_io_size = blocksize; 	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);	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);	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;}