cregit-Linux how code gets into the kernel

Release 4.13 lib/decompress_unlz4.c

Directory: lib
/*
 * Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
 *
 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#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; }

Contributors

PersonTokensPropCommitsCommitProp
Kyungsik Lee54981.58%120.00%
Yinghai Lu10515.60%240.00%
Sven Schmidt142.08%120.00%
Jan Beulich50.74%120.00%
Total673100.00%5100.00%

#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); }

Contributors

PersonTokensPropCommitsCommitProp
Kyungsik Lee7488.10%133.33%
Yinghai Lu1011.90%266.67%
Total84100.00%3100.00%

#endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Kyungsik Lee66983.31%116.67%
Yinghai Lu11514.32%350.00%
Sven Schmidt141.74%116.67%
Jan Beulich50.62%116.67%
Total803100.00%6100.00%
Directory: lib
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