From: Huang Jianan <huangjia...@oppo.com>
In order to use the newest LZ4_decompress_safe_partial() which can
now decode exactly the nb of bytes requested.
Signed-off-by: Huang Jianan <jnhuan...@gmail.com>
---
fs/erofs/Makefile | 3 +-
fs/erofs/lz4.c | 534 ++++++++++++++++++++++++++++++++++++++++++++++
fs/erofs/lz4.h | 4 +
3 files changed, 540 insertions(+), 1 deletion(-)
create mode 100644 fs/erofs/lz4.c
create mode 100644 fs/erofs/lz4.h
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 7398ab7a36..c4fc5b794e 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -4,4 +4,5 @@
obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
super.o \
namei.o \
- data.o
+ data.o \
+ lz4.o
diff --git a/fs/erofs/lz4.c b/fs/erofs/lz4.c
new file mode 100644
index 0000000000..35f67c15eb
--- /dev/null
+++ b/fs/erofs/lz4.c
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL 2.0+ OR BSD-2-Clause
+/*
+ * LZ4 - Fast LZ compression algorithm
+ * Copyright (C) 2011 - 2016, Yann Collet.
+ * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd -
license.php)
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * You can contact the author at :
+ * - LZ4 homepage : http://www.lz4.org
+ * - LZ4 source repository : https://github.com/lz4/lz4
+ */
+#include <common.h>
+#include <compiler.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/bug.h>
+#include <asm/unaligned.h>
+
+#define FORCE_INLINE inline __attribute__((always_inline))
+
+static FORCE_INLINE u16 LZ4_readLE16(const void *src)
+{
+ return get_unaligned_le16(src);
+}
+
+static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
+{
+ put_unaligned(get_unaligned((const u64 *)src), (u64 *)dst);
+}
+
+typedef uint8_t BYTE;
+typedef uint16_t U16;
+typedef uint32_t U32;
+typedef int32_t S32;
+typedef uint64_t U64;
+typedef uintptr_t uptrval;
+
+static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value)
+{
+ put_unaligned(value, (U32 *)memPtr);
+}
+
+/**************************************
+* Reading and writing into memory
+**************************************/
+
+/* customized version of memcpy, which may overwrite up to 7 bytes beyond
dstEnd */
+static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd)
+{
+ BYTE* d = (BYTE*)dstPtr;
+ const BYTE* s = (const BYTE*)srcPtr;
+ BYTE* e = (BYTE*)dstEnd;
+ do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e);
+}
+
+
+/**************************************
+* Common Constants
+**************************************/
+#define MINMATCH 4
+
+#define WILDCOPYLENGTH 8
+#define LASTLITERALS 5
+#define MFLIMIT (WILDCOPYLENGTH + MINMATCH)
+
+/*
+ * ensure it's possible to write 2 x wildcopyLength
+ * without overflowing output buffer
+ */
+#define MATCH_SAFEGUARD_DISTANCE ((2 * WILDCOPYLENGTH) - MINMATCH)
+
+#define KB (1 <<10)
+
+#define MAXD_LOG 16
+#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
+
+#define ML_BITS 4
+#define ML_MASK ((1U<<ML_BITS)-1)
+#define RUN_BITS (8-ML_BITS)
+#define RUN_MASK ((1U<<RUN_BITS)-1)
+
+#define LZ4_STATIC_ASSERT(c) BUILD_BUG_ON(!(c))
+
+/**************************************
+* Local Structures and types
+**************************************/
+typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
+typedef enum { endOnOutputSize = 0, endOnInputSize = 1 }
endCondition_directive;
+typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive;
+
+#define DEBUGLOG(l, ...) {} /* disabled */
+
+#ifndef assert
+#define assert(condition) ((void)0)
+#endif
+
+/*
+ * LZ4_decompress_generic() :
+ * This generic decompression function covers all use cases.
+ * It shall be instantiated several times, using different sets of directives.
+ * Note that it is important for performance that this function really get
inlined,
+ * in order to remove useless branches during compilation optimization.
+ */
+static FORCE_INLINE int LZ4_decompress_generic(
+ const char * const src,
+ char * const dst,
+ int srcSize,
+ /*
+ * If endOnInput == endOnInputSize,
+ * this value is `dstCapacity`
+ */
+ int outputSize,
+ /* endOnOutputSize, endOnInputSize */
+ endCondition_directive endOnInput,
+ /* full, partial */
+ earlyEnd_directive partialDecoding,
+ /* noDict, withPrefix64k, usingExtDict */
+ dict_directive dict,
+ /* always <= dst, == dst when no prefix */
+ const BYTE * const lowPrefix,
+ /* only if dict == usingExtDict */
+ const BYTE * const dictStart,
+ /* note : = 0 if noDict */
+ const size_t dictSize
+ )
+{
+ const BYTE *ip = (const BYTE *) src;
+ const BYTE * const iend = ip + srcSize;
+
+ BYTE *op = (BYTE *) dst;
+ BYTE * const oend = op + outputSize;
+ BYTE *cpy;
+
+ const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
+ static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4};
+ static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3};
+
+ const int safeDecode = (endOnInput == endOnInputSize);
+ const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
+
+ /* Set up the "end" pointers for the shortcut. */
+ const BYTE *const shortiend = iend -
+ (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
+ const BYTE *const shortoend = oend -
+ (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
+
+ DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__,
+ srcSize, outputSize);
+
+ /* Special cases */
+ assert(lowPrefix <= op);
+ assert(src != NULL);
+
+ /* Empty output buffer */
+ if ((endOnInput) && (unlikely(outputSize == 0)))
+ return ((srcSize == 1) && (*ip == 0)) ? 0 : -1;
+
+ if ((!endOnInput) && (unlikely(outputSize == 0)))
+ return (*ip == 0 ? 1 : -1);
+
+ if ((endOnInput) && unlikely(srcSize == 0))
+ return -1;
+
+ /* Main Loop : decode sequences */
+ while (1) {
+ size_t length;
+ const BYTE *match;
+ size_t offset;
+
+ /* get literal length */
+ unsigned int const token = *ip++;
+ length = token>>ML_BITS;
+
+ /* ip < iend before the increment */
+ assert(!endOnInput || ip <= iend);
+
+ /*
+ * A two-stage shortcut for the most common case:
+ * 1) If the literal length is 0..14, and there is enough
+ * space, enter the shortcut and copy 16 bytes on behalf
+ * of the literals (in the fast mode, only 8 bytes can be
+ * safely copied this way).
+ * 2) Further if the match length is 4..18, copy 18 bytes
+ * in a similar manner; but we ensure that there's enough
+ * space in the output for those 18 bytes earlier, upon
+ * entering the shortcut (in other words, there is a
+ * combined check for both stages).
+ *
+ * The & in the likely() below is intentionally not && so that
+ * some compilers can produce better parallelized runtime code
+ */
+ if ((endOnInput ? length != RUN_MASK : length <= 8)
+ /*
+ * strictly "less than" on input, to re-enter
+ * the loop with at least one byte
+ */
+ && likely((endOnInput ? ip < shortiend : 1) &
+ (op <= shortoend))) {
+ /* Copy the literals */
+ memcpy(op, ip, endOnInput ? 16 : 8);
+ op += length; ip += length;
+
+ /*
+ * The second stage:
+ * prepare for match copying, decode full info.
+ * If it doesn't work out, the info won't be wasted.
+ */
+ length = token & ML_MASK; /* match length */
+ offset = LZ4_readLE16(ip);
+ ip += 2;
+ match = op - offset;
+ assert(match <= op); /* check overflow */
+
+ /* Do not deal with overlapping matches. */
+ if ((length != ML_MASK) &&
+ (offset >= 8) &&
+ (dict == withPrefix64k || match >= lowPrefix)) {
+ /* Copy the match. */
+ memcpy(op + 0, match + 0, 8);
+ memcpy(op + 8, match + 8, 8);
+ memcpy(op + 16, match + 16, 2);
+ op += length + MINMATCH;
+ /* Both stages worked, load the next token. */
+ continue;
+ }
+
+ /*
+ * The second stage didn't work out, but the info
+ * is ready. Propel it right to the point of match
+ * copying.
+ */
+ goto _copy_match;
+ }
+
+ /* decode literal length */
+ if (length == RUN_MASK) {
+ unsigned int s;
+
+ if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
+ /* overflow detection */
+ goto _output_error;
+ }
+ do {
+ s = *ip++;
+ length += s;
+ } while (likely(endOnInput
+ ? ip < iend - RUN_MASK
+ : 1) & (s == 255));
+
+ if ((safeDecode)
+ && unlikely((uptrval)(op) +
+ length < (uptrval)(op))) {
+ /* overflow detection */
+ goto _output_error;
+ }
+ if ((safeDecode)
+ && unlikely((uptrval)(ip) +
+ length < (uptrval)(ip))) {
+ /* overflow detection */
+ goto _output_error;
+ }
+ }
+
+ /* copy literals */
+ cpy = op + length;
+ LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
+
+ if (((endOnInput) && ((cpy > oend - MFLIMIT)
+ || (ip + length > iend - (2 + 1 + LASTLITERALS))))
+ || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
+ if (partialDecoding) {
+ if (cpy > oend) {
+ /*
+ * Partial decoding :
+ * stop in the middle of literal segment
+ */
+ cpy = oend;
+ length = oend - op;
+ }
+ if ((endOnInput)
+ && (ip + length > iend)) {
+ /*
+ * Error :
+ * read attempt beyond
+ * end of input buffer
+ */
+ goto _output_error;
+ }
+ } else {
+ if ((!endOnInput)
+ && (cpy != oend)) {
+ /*
+ * Error :
+ * block decoding must
+ * stop exactly there
+ */
+ goto _output_error;
+ }
+ if ((endOnInput)
+ && ((ip + length != iend)
+ || (cpy > oend))) {
+ /*
+ * Error :
+ * input must be consumed
+ */
+ goto _output_error;
+ }
+ }
+
+ /*
+ * supports overlapping memory regions; only matters
+ * for in-place decompression scenarios
+ */
+ memmove(op, ip, length);
+ ip += length;
+ op += length;
+
+ /* Necessarily EOF, due to parsing restrictions */
+ if (!partialDecoding || (cpy == oend))
+ break;
+ } else {
+ /* may overwrite up to WILDCOPYLENGTH beyond cpy */
+ LZ4_wildCopy(op, ip, cpy);
+ ip += length;
+ op = cpy;
+ }
+
+ /* get offset */
+ offset = LZ4_readLE16(ip);
+ ip += 2;
+ match = op - offset;
+
+ /* get matchlength */
+ length = token & ML_MASK;
+
+_copy_match:
+ if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
+ /* Error : offset outside buffers */
+ goto _output_error;
+ }
+
+ /* costs ~1%; silence an msan warning when offset == 0 */
+ /*
+ * note : when partialDecoding, there is no guarantee that
+ * at least 4 bytes remain available in output buffer
+ */
+ if (!partialDecoding) {
+ assert(oend > op);
+ assert(oend - op >= 4);
+
+ LZ4_write32(op, (U32)offset);
+ }
+
+ if (length == ML_MASK) {
+ unsigned int s;
+
+ do {
+ s = *ip++;
+
+ if ((endOnInput) && (ip > iend - LASTLITERALS))
+ goto _output_error;
+
+ length += s;
+ } while (s == 255);
+
+ if ((safeDecode)
+ && unlikely(
+ (uptrval)(op) + length < (uptrval)op)) {
+ /* overflow detection */
+ goto _output_error;
+ }
+ }
+
+ length += MINMATCH;
+
+ /* match starting within external dictionary */
+ if ((dict == usingExtDict) && (match < lowPrefix)) {
+ if (unlikely(op + length > oend - LASTLITERALS)) {
+ /* doesn't respect parsing restriction */
+ if (!partialDecoding)
+ goto _output_error;
+ length = min(length, (size_t)(oend - op));
+ }
+
+ if (length <= (size_t)(lowPrefix - match)) {
+ /*
+ * match fits entirely within external
+ * dictionary : just copy
+ */
+ memmove(op, dictEnd - (lowPrefix - match),
+ length);
+ op += length;
+ } else {
+ /*
+ * match stretches into both external
+ * dictionary and current block
+ */
+ size_t const copySize = (size_t)(lowPrefix -
match);
+ size_t const restSize = length - copySize;
+
+ memcpy(op, dictEnd - copySize, copySize);
+ op += copySize;
+ if (restSize > (size_t)(op - lowPrefix)) {
+ /* overlap copy */
+ BYTE * const endOfMatch = op + restSize;
+ const BYTE *copyFrom = lowPrefix;
+
+ while (op < endOfMatch)
+ *op++ = *copyFrom++;
+ } else {
+ memcpy(op, lowPrefix, restSize);
+ op += restSize;
+ }
+ }
+ continue;
+ }
+
+ /* copy match within block */
+ cpy = op + length;
+
+ /*
+ * partialDecoding :
+ * may not respect endBlock parsing restrictions
+ */
+ assert(op <= oend);
+ if (partialDecoding &&
+ (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
+ size_t const mlen = min(length, (size_t)(oend - op));
+ const BYTE * const matchEnd = match + mlen;
+ BYTE * const copyEnd = op + mlen;
+
+ if (matchEnd > op) {
+ /* overlap copy */
+ while (op < copyEnd)
+ *op++ = *match++;
+ } else {
+ memcpy(op, match, mlen);
+ }
+ op = copyEnd;
+ if (op == oend)
+ break;
+ continue;
+ }
+
+ if (unlikely(offset < 8)) {
+ op[0] = match[0];
+ op[1] = match[1];
+ op[2] = match[2];
+ op[3] = match[3];
+ match += inc32table[offset];
+ memcpy(op + 4, match, 4);
+ match -= dec64table[offset];
+ } else {
+ LZ4_copy8(op, match);
+ match += 8;
+ }
+
+ op += 8;
+
+ if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
+ BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
+
+ if (cpy > oend - LASTLITERALS) {
+ /*
+ * Error : last LASTLITERALS bytes
+ * must be literals (uncompressed)
+ */
+ goto _output_error;
+ }
+
+ if (op < oCopyLimit) {
+ LZ4_wildCopy(op, match, oCopyLimit);
+ match += oCopyLimit - op;
+ op = oCopyLimit;
+ }
+ while (op < cpy)
+ *op++ = *match++;
+ } else {
+ LZ4_copy8(op, match);
+ if (length > 16)
+ LZ4_wildCopy(op + 8, match + 8, cpy);
+ }
+ op = cpy; /* wildcopy correction */
+ }
+
+ /* end of decoding */
+ if (endOnInput) {
+ /* Nb of output bytes decoded */
+ return (int) (((char *)op) - dst);
+ } else {
+ /* Nb of input bytes read */
+ return (int) (((const char *)ip) - src);
+ }
+
+ /* Overflow error detected */
+_output_error:
+ return (int) (-(((const char *)ip) - src)) - 1;
+}
+
+int LZ4_decompress_safe(const char *source, char *dest,
+ int compressedSize, int maxDecompressedSize)
+{
+ return LZ4_decompress_generic(source, dest,
+ compressedSize, maxDecompressedSize,
+ endOnInputSize, decode_full_block,
+ noDict, (BYTE *)dest, NULL, 0);
+}
+
+int LZ4_decompress_safe_partial(const char *src, char *dst,
+ int compressedSize, int targetOutputSize, int dstCapacity)
+{
+ dstCapacity = min(targetOutputSize, dstCapacity);
+ return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
+ endOnInputSize, partial_decode,
+ noDict, (BYTE *)dst, NULL, 0);
+}
diff --git a/fs/erofs/lz4.h b/fs/erofs/lz4.h
new file mode 100644
index 0000000000..0b4bdf4fbe
--- /dev/null
+++ b/fs/erofs/lz4.h
@@ -0,0 +1,4 @@
+int LZ4_decompress_safe(const char *source, char *dest,
+ int compressedSize, int maxDecompressedSize);
+int LZ4_decompress_safe_partial(const char *src, char *dst,
+ int compressedSize, int targetOutputSize, int dstCapacity);
--
2.25.1
