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/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2012 S-G Bergh <sgb@systemasis.org>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_SQUASHFS) += squashfs.o
//config:config FEATURE_VOLUMEID_SQUASHFS
//config: bool "SquashFS filesystem"
//config: default y
//config: depends on VOLUMEID && FEATURE_BLKID_TYPE
//config: help
//config: Squashfs is a compressed read-only filesystem for Linux. Squashfs is
//config: intended for general read-only filesystem use and in constrained block
//config: device/memory systems (e.g. embedded systems) where low overhead is
//config: needed.
#include "volume_id_internal.h"
struct squashfs_superblock {
uint32_t magic;
/*
uint32_t dummy[6];
uint16_t major;
uint16_t minor;
*/
} PACKED;
int FAST_FUNC volume_id_probe_squashfs(struct volume_id *id /*,uint64_t off*/)
{
#define off ((uint64_t)0)
struct squashfs_superblock *sb;
dbg("SquashFS: probing at offset 0x%llx", (unsigned long long) off);
sb = volume_id_get_buffer(id, off, 0x200);
if (!sb)
return -1;
// Old SquashFS (pre 4.0) can be both big and little endian, so test for both.
// Likewise, it is commonly used in firwmare with some non-standard signatures.
#define pack(a,b,c,d) ( (uint32_t)((a * 256 + b) * 256 + c) * 256 + d )
#define SIG1 pack('s','q','s','h')
#define SIG2 pack('h','s','q','s')
#define SIG3 pack('s','h','s','q')
#define SIG4 pack('q','s','h','s')
if (sb->magic == SIG1
|| sb->magic == SIG2
|| sb->magic == SIG3
|| sb->magic == SIG4
) {
IF_FEATURE_BLKID_TYPE(id->type = "squashfs";)
return 0;
}
return -1;
}
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