1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mozglue/linker/SeekableZStream.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,262 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.6 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#include <algorithm>
1.9 +#include "SeekableZStream.h"
1.10 +#include "Logging.h"
1.11 +
1.12 +bool
1.13 +SeekableZStream::Init(const void *buf, size_t length)
1.14 +{
1.15 + const SeekableZStreamHeader *header = SeekableZStreamHeader::validate(buf);
1.16 + if (!header) {
1.17 + LOG("Not a seekable zstream");
1.18 + return false;
1.19 + }
1.20 +
1.21 + buffer = reinterpret_cast<const unsigned char *>(buf);
1.22 + totalSize = header->totalSize;
1.23 + chunkSize = header->chunkSize;
1.24 + lastChunkSize = header->lastChunkSize;
1.25 + windowBits = header->windowBits;
1.26 + dictionary.Init(buffer + sizeof(SeekableZStreamHeader), header->dictSize);
1.27 + offsetTable.Init(buffer + sizeof(SeekableZStreamHeader) + header->dictSize,
1.28 + header->nChunks);
1.29 + filter = GetFilter(header->filter);
1.30 +
1.31 + /* Sanity check */
1.32 + if ((chunkSize == 0) ||
1.33 + (!IsPageAlignedSize(chunkSize)) ||
1.34 + (chunkSize > 8 * PageSize()) ||
1.35 + (offsetTable.numElements() < 1) ||
1.36 + (lastChunkSize == 0) ||
1.37 + (lastChunkSize > chunkSize) ||
1.38 + (length < totalSize)) {
1.39 + LOG("Malformed or broken seekable zstream");
1.40 + return false;
1.41 + }
1.42 +
1.43 + return true;
1.44 +}
1.45 +
1.46 +bool
1.47 +SeekableZStream::Decompress(void *where, size_t chunk, size_t length)
1.48 +{
1.49 + while (length) {
1.50 + size_t len = std::min(length, static_cast<size_t>(chunkSize));
1.51 + if (!DecompressChunk(where, chunk, len))
1.52 + return false;
1.53 + where = reinterpret_cast<unsigned char *>(where) + len;
1.54 + length -= len;
1.55 + chunk++;
1.56 + }
1.57 + return true;
1.58 +}
1.59 +
1.60 +bool
1.61 +SeekableZStream::DecompressChunk(void *where, size_t chunk, size_t length)
1.62 +{
1.63 + if (chunk >= offsetTable.numElements()) {
1.64 + LOG("DecompressChunk: chunk #%" PRIdSize " out of range [0-%" PRIdSize ")",
1.65 + chunk, offsetTable.numElements());
1.66 + return false;
1.67 + }
1.68 +
1.69 + bool isLastChunk = (chunk == offsetTable.numElements() - 1);
1.70 +
1.71 + size_t chunkLen = isLastChunk ? lastChunkSize : chunkSize;
1.72 +
1.73 + if (length == 0 || length > chunkLen)
1.74 + length = chunkLen;
1.75 +
1.76 + DEBUG_LOG("DecompressChunk #%" PRIdSize " @%p (%" PRIdSize "/% " PRIdSize ")",
1.77 + chunk, where, length, chunkLen);
1.78 + z_stream zStream;
1.79 + memset(&zStream, 0, sizeof(zStream));
1.80 + zStream.avail_in = (isLastChunk ? totalSize : uint32_t(offsetTable[chunk + 1]))
1.81 + - uint32_t(offsetTable[chunk]);
1.82 + zStream.next_in = const_cast<Bytef *>(buffer + uint32_t(offsetTable[chunk]));
1.83 + zStream.avail_out = length;
1.84 + zStream.next_out = reinterpret_cast<Bytef *>(where);
1.85 +
1.86 + /* Decompress chunk */
1.87 + if (inflateInit2(&zStream, windowBits) != Z_OK) {
1.88 + LOG("inflateInit failed: %s", zStream.msg);
1.89 + return false;
1.90 + }
1.91 + if (dictionary && inflateSetDictionary(&zStream, dictionary,
1.92 + dictionary.numElements()) != Z_OK) {
1.93 + LOG("inflateSetDictionary failed: %s", zStream.msg);
1.94 + return false;
1.95 + }
1.96 + if (inflate(&zStream, (length == chunkLen) ? Z_FINISH : Z_SYNC_FLUSH)
1.97 + != (length == chunkLen) ? Z_STREAM_END : Z_OK) {
1.98 + LOG("inflate failed: %s", zStream.msg);
1.99 + return false;
1.100 + }
1.101 + if (inflateEnd(&zStream) != Z_OK) {
1.102 + LOG("inflateEnd failed: %s", zStream.msg);
1.103 + return false;
1.104 + }
1.105 + if (filter)
1.106 + filter(chunk * chunkSize, UNFILTER, (unsigned char *)where, chunkLen);
1.107 +
1.108 + return true;
1.109 +}
1.110 +
1.111 +/* Branch/Call/Jump conversion filter for Thumb, derived from xz-utils
1.112 + * by Igor Pavlov and Lasse Collin, published in the public domain */
1.113 +static void
1.114 +BCJ_Thumb_filter(off_t offset, SeekableZStream::FilterDirection dir,
1.115 + unsigned char *buf, size_t size)
1.116 +{
1.117 + size_t i;
1.118 + for (i = 0; i + 4 <= size; i += 2) {
1.119 + if ((buf[i + 1] & 0xf8) == 0xf0 && (buf[i + 3] & 0xf8) == 0xf8) {
1.120 + uint32_t src = (buf[i] << 11)
1.121 + | ((buf[i + 1] & 0x07) << 19)
1.122 + | buf[i + 2]
1.123 + | ((buf[i + 3] & 0x07) << 8);
1.124 + src <<= 1;
1.125 + uint32_t dest;
1.126 + if (dir == SeekableZStream::FILTER)
1.127 + dest = offset + (uint32_t)(i) + 4 + src;
1.128 + else
1.129 + dest = src - (offset + (uint32_t)(i) + 4);
1.130 +
1.131 + dest >>= 1;
1.132 + buf[i] = dest >> 11;
1.133 + buf[i + 1] = 0xf0 | ((dest >> 19) & 0x07);
1.134 + buf[i + 2] = dest;
1.135 + buf[i + 3] = 0xf8 | ((dest >> 8) & 0x07);
1.136 + i += 2;
1.137 + }
1.138 + }
1.139 +}
1.140 +
1.141 +/* Branch/Call/Jump conversion filter for ARM, derived from xz-utils
1.142 + * by Igor Pavlov and Lasse Collin, published in the public domain */
1.143 +static void
1.144 +BCJ_ARM_filter(off_t offset, SeekableZStream::FilterDirection dir,
1.145 + unsigned char *buf, size_t size)
1.146 +{
1.147 + size_t i;
1.148 + for (i = 0; i + 4 <= size; i += 4) {
1.149 + if (buf[i + 3] == 0xeb) {
1.150 + uint32_t src = buf[i]
1.151 + | (buf[i + 1] << 8)
1.152 + | (buf[i + 2] << 16);
1.153 + src <<= 2;
1.154 + uint32_t dest;
1.155 + if (dir == SeekableZStream::FILTER)
1.156 + dest = offset + (uint32_t)(i) + 8 + src;
1.157 + else
1.158 + dest = src - (offset + (uint32_t)(i) + 8);
1.159 +
1.160 + dest >>= 2;
1.161 + buf[i] = dest;
1.162 + buf[i + 1] = dest >> 8;
1.163 + buf[i + 2] = dest >> 16;
1.164 + }
1.165 + }
1.166 +}
1.167 +
1.168 +/* Branch/Call/Jump conversion filter for x86, derived from xz-utils
1.169 + * by Igor Pavlov and Lasse Collin, published in the public domain */
1.170 +
1.171 +#define Test86MSByte(b) ((b) == 0 || (b) == 0xff)
1.172 +
1.173 +static void
1.174 +BCJ_X86_filter(off_t offset, SeekableZStream::FilterDirection dir,
1.175 + unsigned char *buf, size_t size)
1.176 +{
1.177 + static const bool MASK_TO_ALLOWED_STATUS[8] =
1.178 + { true, true, true, false, true, false, false, false };
1.179 +
1.180 + static const uint32_t MASK_TO_BIT_NUMBER[8] =
1.181 + { 0, 1, 2, 2, 3, 3, 3, 3 };
1.182 +
1.183 + uint32_t prev_mask = 0;
1.184 + uint32_t prev_pos = 0;
1.185 +
1.186 + for (size_t i = 0; i + 5 <= size;) {
1.187 + uint8_t b = buf[i];
1.188 + if (b != 0xe8 && b != 0xe9) {
1.189 + ++i;
1.190 + continue;
1.191 + }
1.192 +
1.193 + const uint32_t off = offset + (uint32_t)(i) - prev_pos;
1.194 + prev_pos = offset + (uint32_t)(i);
1.195 +
1.196 + if (off > 5) {
1.197 + prev_mask = 0;
1.198 + } else {
1.199 + for (uint32_t i = 0; i < off; ++i) {
1.200 + prev_mask &= 0x77;
1.201 + prev_mask <<= 1;
1.202 + }
1.203 + }
1.204 +
1.205 + b = buf[i + 4];
1.206 +
1.207 + if (Test86MSByte(b) && MASK_TO_ALLOWED_STATUS[(prev_mask >> 1) & 0x7]
1.208 + && (prev_mask >> 1) < 0x10) {
1.209 +
1.210 + uint32_t src = ((uint32_t)(b) << 24)
1.211 + | ((uint32_t)(buf[i + 3]) << 16)
1.212 + | ((uint32_t)(buf[i + 2]) << 8)
1.213 + | (buf[i + 1]);
1.214 +
1.215 + uint32_t dest;
1.216 + while (true) {
1.217 + if (dir == SeekableZStream::FILTER)
1.218 + dest = src + (offset + (uint32_t)(i) + 5);
1.219 + else
1.220 + dest = src - (offset + (uint32_t)(i) + 5);
1.221 +
1.222 + if (prev_mask == 0)
1.223 + break;
1.224 +
1.225 + const uint32_t i = MASK_TO_BIT_NUMBER[prev_mask >> 1];
1.226 +
1.227 + b = (uint8_t)(dest >> (24 - i * 8));
1.228 +
1.229 + if (!Test86MSByte(b))
1.230 + break;
1.231 +
1.232 + src = dest ^ ((1 << (32 - i * 8)) - 1);
1.233 + }
1.234 +
1.235 + buf[i + 4] = (uint8_t)(~(((dest >> 24) & 1) - 1));
1.236 + buf[i + 3] = (uint8_t)(dest >> 16);
1.237 + buf[i + 2] = (uint8_t)(dest >> 8);
1.238 + buf[i + 1] = (uint8_t)(dest);
1.239 + i += 5;
1.240 + prev_mask = 0;
1.241 +
1.242 + } else {
1.243 + ++i;
1.244 + prev_mask |= 1;
1.245 + if (Test86MSByte(b))
1.246 + prev_mask |= 0x10;
1.247 + }
1.248 + }
1.249 +}
1.250 +
1.251 +SeekableZStream::ZStreamFilter
1.252 +SeekableZStream::GetFilter(SeekableZStream::FilterId id)
1.253 +{
1.254 + switch (id) {
1.255 + case BCJ_THUMB:
1.256 + return BCJ_Thumb_filter;
1.257 + case BCJ_ARM:
1.258 + return BCJ_ARM_filter;
1.259 + case BCJ_X86:
1.260 + return BCJ_X86_filter;
1.261 + default:
1.262 + return nullptr;
1.263 + }
1.264 + return nullptr;
1.265 +}
