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