freebsd-dev/usr.sbin/fstyp/exfat.c

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/*
* Copyright (c) 2017 Conrad Meyer <cem@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "fstyp.h"
struct exfat_vbr {
char ev_jmp[3];
char ev_fsname[8];
char ev_zeros[53];
uint64_t ev_part_offset;
uint64_t ev_vol_length;
uint32_t ev_fat_offset;
uint32_t ev_fat_length;
uint32_t ev_cluster_offset;
uint32_t ev_cluster_count;
uint32_t ev_rootdir_cluster;
uint32_t ev_vol_serial;
uint16_t ev_fs_revision;
uint16_t ev_vol_flags;
uint8_t ev_log_bytes_per_sect;
uint8_t ev_log_sect_per_clust;
uint8_t ev_num_fats;
uint8_t ev_drive_sel;
uint8_t ev_percent_used;
} __packed;
int
fstyp_exfat(FILE *fp, char *label, size_t size)
{
struct exfat_vbr *ev;
ev = (struct exfat_vbr *)read_buf(fp, 0, 512);
if (ev == NULL || strncmp(ev->ev_fsname, "EXFAT ", 8) != 0)
goto fail;
/*
* Reading the volume label requires walking the root directory to look
* for a special label file. Left as an exercise for the reader.
*/
free(ev);
return (0);
fail:
free(ev);
return (1);
}