/* * 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: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. //config: #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; }