lib/lz4_android.c

// SPDX-License-Identifier: GPL 2.0+ OR BSD-3-Clause
/*
 * Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
 *
 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
 */

#include <amlogic/unlz4_android.h>
#include <common.h>
#include <compiler.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <amlogic/lz4.h>

static u16 LZ4_readLE16(const void *src) { return le16_to_cpu(*(u16 *)src); }
static void LZ4_copy4(void *dst, const void *src) { *(u32 *)dst = *(u32 *)src; }
static void LZ4_copy8(void *dst, const void *src) { *(u64 *)dst = *(u64 *)src; }

typedef  uint8_t BYTE;
typedef uint16_t U16;
typedef uint32_t U32;
typedef  int32_t S32;
typedef uint64_t U64;

#define FORCE_INLINE static inline __attribute__((always_inline))

/* Unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
#include "lz4.c"	/* #include for inlining, do not link! */

/*
 * Note: Uncompressed chunk size is used in the compressor side
 * (userspace side for compression).
 * It is hardcoded because there is not proper way to extract it
 * from the binary stream which is generated by the preliminary
 * version of LZ4 tool so far.
 */
#define LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE (8 << 20)
#define ARCHIVE_MAGICNUMBER 0x184C2102

int unlz4(const void *src, size_t srcn, void *dst, size_t *dstn)
{
	int ret = -1;
	size_t chunksize = 0;
	size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
	long size = srcn;
	size_t dest_len;
	const void *inp = src;
	void *outp = dst;
	*dstn = 0;

	chunksize = le32_to_cpu(*(u32 *)inp);
	printf("magic: 0x%lX, LZ4F_MAGIC: 0x%X\n", chunksize, ARCHIVE_MAGICNUMBER);
	if (chunksize == ARCHIVE_MAGICNUMBER) {
		inp += 4;
		size -= 4;
	} else {
		printf("invalid header\n");
		goto exit;
	}

	for (;;) {
		if (size < 4) {
			/* empty or end-of-file */
			printf("empty or end-of-file\n");
			goto exit1;
		}

		chunksize = le32_to_cpu(*(u32 *)inp);
		if (chunksize == ARCHIVE_MAGICNUMBER) {
			inp += 4;
			size -= 4;
			continue;
		}

		if (chunksize == 0) {
			/* empty or end-of-file */
			printf("empty or end-of-file\n");
			goto exit1;
		}

		inp += 4;
		size -= 4;
		dest_len = uncomp_chunksize;

		ret = LZ4_decompress_generic(inp, outp, chunksize,
					dest_len, endOnInputSize,
					full, 0, noDict, outp, NULL, 0);
		dest_len = ret;

		if (ret < 0) {
			printf("Decoding failed\n");
			goto exit;
		}

		ret = -1;
		outp += dest_len;
		size -= chunksize;

		if (size == 0) {
			break;
		} else if (size < 0) {
			printf("data corrupted\n");
			goto exit;
		}
		inp += chunksize;
	}

exit1:
	ret = 0;

exit:
	return ret;
}