decompress_unlz4.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
*
* Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
*/
#ifdef STATIC
#define PREBOOT
#include "lz4/lz4_decompress.c"
#else
#include <linux/decompress/unlz4.h>
#endif
#include <linux/types.h>
#include <linux/lz4.h>
#include <linux/decompress/mm.h>
#include <linux/compiler.h>
#include <asm/unaligned.h>
/*
* 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
STATIC inline int INIT unlz4(u8 *input, long in_len,
long (*fill)(void *, unsigned long),
long (*flush)(void *, unsigned long),
u8 *output, long *posp,
void (*error) (char *x))
{
int ret = -1;
size_t chunksize = 0;
size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
u8 *inp;
u8 *inp_start;
u8 *outp;
long size = in_len;
#ifdef PREBOOT
size_t out_len = get_unaligned_le32(input + in_len);
#endif
size_t dest_len;
if (output) {
outp = output;
} else if (!flush) {
error("NULL output pointer and no flush function provided");
goto exit_0;
} else {
outp = large_malloc(uncomp_chunksize);
if (!outp) {
error("Could not allocate output buffer");
goto exit_0;
}
}
if (input && fill) {
error("Both input pointer and fill function provided,");
goto exit_1;
} else if (input) {
inp = input;
} else if (!fill) {
error("NULL input pointer and missing fill function");
goto exit_1;
} else {
inp = large_malloc(LZ4_compressBound(uncomp_chunksize));
if (!inp) {
error("Could not allocate input buffer");
goto exit_1;
}
}
inp_start = inp;
if (posp)
*posp = 0;
if (fill) {
size = fill(inp, 4);
if (size < 4) {
error("data corrupted");
goto exit_2;
}
}
chunksize = get_unaligned_le32(inp);
if (chunksize == ARCHIVE_MAGICNUMBER) {
if (!fill) {
inp += 4;
size -= 4;
}
} else {
error("invalid header");
goto exit_2;
}
if (posp)
*posp += 4;
for (;;) {
if (fill) {
size = fill(inp, 4);
if (size == 0)
break;
if (size < 4) {
error("data corrupted");
goto exit_2;
}
}
chunksize = get_unaligned_le32(inp);
if (chunksize == ARCHIVE_MAGICNUMBER) {
if (!fill) {
inp += 4;
size -= 4;
}
if (posp)
*posp += 4;
continue;
}
if (posp)
*posp += 4;
if (!fill) {
inp += 4;
size -= 4;
} else {
if (chunksize > LZ4_compressBound(uncomp_chunksize)) {
error("chunk length is longer than allocated");
goto exit_2;
}
size = fill(inp, chunksize);
if (size < chunksize) {
error("data corrupted");
goto exit_2;
}
}
#ifdef PREBOOT
if (out_len >= uncomp_chunksize) {
dest_len = uncomp_chunksize;
out_len -= dest_len;
} else
dest_len = out_len;
ret = LZ4_decompress_fast(inp, outp, dest_len);
chunksize = ret;
#else
dest_len = uncomp_chunksize;
ret = LZ4_decompress_safe(inp, outp, chunksize, dest_len);
dest_len = ret;
#endif
if (ret < 0) {
error("Decoding failed");
goto exit_2;
}
ret = -1;
if (flush && flush(outp, dest_len) != dest_len)
goto exit_2;
if (output)
outp += dest_len;
if (posp)
*posp += chunksize;
if (!fill) {
size -= chunksize;
if (size == 0)
break;
else if (size < 0) {
error("data corrupted");
goto exit_2;
}
inp += chunksize;
}
}
ret = 0;
exit_2:
if (!input)
large_free(inp_start);
exit_1:
if (!output)
large_free(outp);
exit_0:
return ret;
}
#ifdef PREBOOT
STATIC int INIT __decompress(unsigned char *buf, long in_len,
long (*fill)(void*, unsigned long),
long (*flush)(void*, unsigned long),
unsigned char *output, long out_len,
long *posp,
void (*error)(char *x)
)
{
return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
}
#endif