зеркало из https://github.com/mozilla/gecko-dev.git
455 строки
14 KiB
C++
455 строки
14 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <cstring>
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#include <cstdlib>
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#include <cstdio>
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#include <string>
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#include "Mappable.h"
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#include "mozilla/IntegerPrintfMacros.h"
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#include "mozilla/UniquePtr.h"
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#ifdef ANDROID
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#include <linux/ashmem.h>
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#endif
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#include <sys/stat.h>
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#include <errno.h>
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#include "ElfLoader.h"
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#include "XZStream.h"
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#include "Logging.h"
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using mozilla::MakeUnique;
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using mozilla::UniquePtr;
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class CacheValidator
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{
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public:
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CacheValidator(const char* aCachedLibPath, Zip* aZip, Zip::Stream* aStream)
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: mCachedLibPath(aCachedLibPath)
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{
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static const char kChecksumSuffix[] = ".crc";
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mCachedChecksumPath =
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MakeUnique<char[]>(strlen(aCachedLibPath) + sizeof(kChecksumSuffix));
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sprintf(mCachedChecksumPath.get(), "%s%s", aCachedLibPath, kChecksumSuffix);
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DEBUG_LOG("mCachedChecksumPath: %s", mCachedChecksumPath.get());
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mChecksum = aStream->GetCRC32();
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DEBUG_LOG("mChecksum: %x", mChecksum);
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}
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// Returns whether the cache is valid and up-to-date.
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bool IsValid() const
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{
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// Validate based on checksum.
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RefPtr<Mappable> checksumMap = MappableFile::Create(mCachedChecksumPath.get());
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if (!checksumMap) {
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// Force caching if checksum is missing in cache.
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return false;
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}
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DEBUG_LOG("Comparing %x with %s", mChecksum, mCachedChecksumPath.get());
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MappedPtr checksumBuf = checksumMap->mmap(nullptr, checksumMap->GetLength(),
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PROT_READ, MAP_PRIVATE, 0);
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if (checksumBuf == MAP_FAILED) {
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WARN("Couldn't map %s to validate checksum", mCachedChecksumPath.get());
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return false;
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}
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if (memcmp(checksumBuf, &mChecksum, sizeof(mChecksum))) {
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return false;
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}
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return !access(mCachedLibPath.c_str(), R_OK);
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}
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// Caches the APK-provided checksum used in future cache validations.
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void CacheChecksum() const
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{
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AutoCloseFD fd(open(mCachedChecksumPath.get(),
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O_TRUNC | O_RDWR | O_CREAT | O_NOATIME,
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S_IRUSR | S_IWUSR));
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if (fd == -1) {
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WARN("Couldn't open %s to update checksum", mCachedChecksumPath.get());
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return;
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}
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DEBUG_LOG("Updating checksum %s", mCachedChecksumPath.get());
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const size_t size = sizeof(mChecksum);
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size_t written = 0;
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while (written < size) {
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ssize_t ret = write(fd,
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reinterpret_cast<const uint8_t*>(&mChecksum) + written,
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size - written);
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if (ret >= 0) {
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written += ret;
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} else if (errno != EINTR) {
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WARN("Writing checksum %s failed with errno %d",
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mCachedChecksumPath.get(), errno);
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break;
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}
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}
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}
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private:
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const std::string mCachedLibPath;
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UniquePtr<char[]> mCachedChecksumPath;
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uint32_t mChecksum;
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};
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Mappable *
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MappableFile::Create(const char *path)
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{
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int fd = open(path, O_RDONLY);
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if (fd != -1)
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return new MappableFile(fd);
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return nullptr;
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}
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MemoryRange
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MappableFile::mmap(const void *addr, size_t length, int prot, int flags,
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off_t offset)
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{
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MOZ_ASSERT(fd != -1);
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MOZ_ASSERT(!(flags & MAP_SHARED));
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flags |= MAP_PRIVATE;
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return MemoryRange::mmap(const_cast<void *>(addr), length, prot, flags,
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fd, offset);
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}
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void
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MappableFile::finalize()
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{
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/* Close file ; equivalent to close(fd.forget()) */
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fd = -1;
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}
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size_t
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MappableFile::GetLength() const
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{
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struct stat st;
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return fstat(fd, &st) ? 0 : st.st_size;
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}
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Mappable *
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MappableExtractFile::Create(const char *name, Zip *zip, Zip::Stream *stream)
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{
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MOZ_ASSERT(zip && stream);
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const char *cachePath = getenv("MOZ_LINKER_CACHE");
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if (!cachePath || !*cachePath) {
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WARN("MOZ_LINKER_EXTRACT is set, but not MOZ_LINKER_CACHE; "
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"not extracting");
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return nullptr;
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}
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// Ensure that the cache dir is private.
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chmod(cachePath, 0770);
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UniquePtr<char[]> path =
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MakeUnique<char[]>(strlen(cachePath) + strlen(name) + 2);
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sprintf(path.get(), "%s/%s", cachePath, name);
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CacheValidator validator(path.get(), zip, stream);
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if (validator.IsValid()) {
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DEBUG_LOG("Reusing %s", static_cast<char *>(path.get()));
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return MappableFile::Create(path.get());
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}
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DEBUG_LOG("Extracting to %s", static_cast<char *>(path.get()));
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AutoCloseFD fd;
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fd = open(path.get(), O_TRUNC | O_RDWR | O_CREAT | O_NOATIME,
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S_IRUSR | S_IWUSR);
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if (fd == -1) {
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ERROR("Couldn't open %s to decompress library", path.get());
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return nullptr;
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}
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AutoUnlinkFile file(path.release());
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if (stream->GetType() == Zip::Stream::DEFLATE) {
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if (ftruncate(fd, stream->GetUncompressedSize()) == -1) {
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ERROR("Couldn't ftruncate %s to decompress library", file.get());
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return nullptr;
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}
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/* Map the temporary file for use as inflate buffer */
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MappedPtr buffer(MemoryRange::mmap(nullptr, stream->GetUncompressedSize(),
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PROT_WRITE, MAP_SHARED, fd, 0));
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if (buffer == MAP_FAILED) {
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ERROR("Couldn't map %s to decompress library", file.get());
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return nullptr;
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}
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z_stream zStream = stream->GetZStream(buffer);
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/* Decompress */
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if (inflateInit2(&zStream, -MAX_WBITS) != Z_OK) {
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ERROR("inflateInit failed: %s", zStream.msg);
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return nullptr;
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}
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if (inflate(&zStream, Z_FINISH) != Z_STREAM_END) {
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ERROR("inflate failed: %s", zStream.msg);
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return nullptr;
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}
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if (inflateEnd(&zStream) != Z_OK) {
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ERROR("inflateEnd failed: %s", zStream.msg);
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return nullptr;
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}
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if (zStream.total_out != stream->GetUncompressedSize()) {
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ERROR("File not fully uncompressed! %ld / %d", zStream.total_out,
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static_cast<unsigned int>(stream->GetUncompressedSize()));
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return nullptr;
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}
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} else if (XZStream::IsXZ(stream->GetBuffer(), stream->GetSize())) {
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XZStream xzStream(stream->GetBuffer(), stream->GetSize());
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if (!xzStream.Init()) {
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ERROR("Couldn't initialize XZ decoder");
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return nullptr;
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}
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DEBUG_LOG("XZStream created, compressed=%" PRIuPTR
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", uncompressed=%" PRIuPTR,
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xzStream.Size(), xzStream.UncompressedSize());
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if (ftruncate(fd, xzStream.UncompressedSize()) == -1) {
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ERROR("Couldn't ftruncate %s to decompress library", file.get());
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return nullptr;
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}
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MappedPtr buffer(MemoryRange::mmap(nullptr, xzStream.UncompressedSize(),
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PROT_WRITE, MAP_SHARED, fd, 0));
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if (buffer == MAP_FAILED) {
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ERROR("Couldn't map %s to decompress library", file.get());
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return nullptr;
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}
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const size_t written = xzStream.Decode(buffer, buffer.GetLength());
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DEBUG_LOG("XZStream decoded %" PRIuPTR, written);
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if (written != buffer.GetLength()) {
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ERROR("Error decoding XZ file %s", file.get());
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return nullptr;
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}
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} else {
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return nullptr;
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}
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validator.CacheChecksum();
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return new MappableExtractFile(fd.forget(), file.release());
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}
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/**
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* _MappableBuffer is a buffer which content can be mapped at different
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* locations in the virtual address space.
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* On Linux, uses a (deleted) temporary file on a tmpfs for sharable content.
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* On Android, uses ashmem.
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*/
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class _MappableBuffer: public MappedPtr
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{
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public:
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/**
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* Returns a _MappableBuffer instance with the given name and the given
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* length.
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*/
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static _MappableBuffer *Create(const char *name, size_t length)
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{
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AutoCloseFD fd;
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#ifdef ANDROID
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/* On Android, initialize an ashmem region with the given length */
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fd = open("/" ASHMEM_NAME_DEF, O_RDWR, 0600);
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if (fd == -1)
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return nullptr;
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char str[ASHMEM_NAME_LEN];
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strlcpy(str, name, sizeof(str));
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ioctl(fd, ASHMEM_SET_NAME, str);
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if (ioctl(fd, ASHMEM_SET_SIZE, length))
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return nullptr;
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/* The Gecko crash reporter is confused by adjacent memory mappings of
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* the same file and chances are we're going to map from the same file
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* descriptor right away. To avoid problems with the crash reporter,
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* create an empty anonymous page before or after the ashmem mapping,
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* depending on how mappings grow in the address space.
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*/
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#if defined(__arm__)
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// Address increases on ARM.
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void *buf = ::mmap(nullptr, length + PAGE_SIZE, PROT_READ | PROT_WRITE,
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MAP_SHARED, fd, 0);
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if (buf != MAP_FAILED) {
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::mmap(AlignedEndPtr(reinterpret_cast<char *>(buf) + length, PAGE_SIZE),
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PAGE_SIZE, PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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DEBUG_LOG("Decompression buffer of size 0x%" PRIxPTR
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" in ashmem \"%s\", mapped @%p",
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length, str, buf);
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return new _MappableBuffer(fd.forget(), buf, length);
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}
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#elif defined(__i386__) || defined(__aarch64__)
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// Address decreases on x86 and AArch64.
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size_t anon_mapping_length = length + PAGE_SIZE;
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void *buf = ::mmap(nullptr, anon_mapping_length, PROT_NONE,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if (buf != MAP_FAILED) {
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char *first_page = reinterpret_cast<char *>(buf);
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char *map_page = first_page + PAGE_SIZE;
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void *actual_buf = ::mmap(map_page, length, PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_SHARED, fd, 0);
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if (actual_buf == MAP_FAILED) {
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::munmap(buf, anon_mapping_length);
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DEBUG_LOG("Fixed allocation of decompression buffer at %p failed", map_page);
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return nullptr;
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}
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DEBUG_LOG("Decompression buffer of size 0x%" PRIxPTR
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" in ashmem \"%s\", mapped @%p", length, str, actual_buf);
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return new _MappableBuffer(fd.forget(), actual_buf, length);
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}
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#else
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#error need to add a case for your CPU
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#endif
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#else
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/* On Linux, use /dev/shm as base directory for temporary files, assuming
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* it's on tmpfs */
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/* TODO: check that /dev/shm is tmpfs */
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char path[256];
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sprintf(path, "/dev/shm/%s.XXXXXX", name);
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fd = mkstemp(path);
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if (fd == -1)
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return nullptr;
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unlink(path);
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ftruncate(fd, length);
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void *buf = ::mmap(nullptr, length, PROT_READ | PROT_WRITE,
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MAP_SHARED, fd, 0);
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if (buf != MAP_FAILED) {
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DEBUG_LOG("Decompression buffer of size %ld in \"%s\", mapped @%p",
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length, path, buf);
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return new _MappableBuffer(fd.forget(), buf, length);
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}
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#endif
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return nullptr;
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}
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void *mmap(const void *addr, size_t length, int prot, int flags, off_t offset)
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{
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MOZ_ASSERT(fd != -1);
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#ifdef ANDROID
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/* Mapping ashmem MAP_PRIVATE is like mapping anonymous memory, even when
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* there is content in the ashmem */
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if (flags & MAP_PRIVATE) {
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flags &= ~MAP_PRIVATE;
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flags |= MAP_SHARED;
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}
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#endif
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return ::mmap(const_cast<void *>(addr), length, prot, flags, fd, offset);
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}
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#ifdef ANDROID
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~_MappableBuffer() {
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/* Free the additional page we allocated. See _MappableBuffer::Create */
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#if defined(__arm__)
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::munmap(AlignedEndPtr(*this + GetLength(), PAGE_SIZE), PAGE_SIZE);
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#elif defined(__i386__) || defined(__aarch64__)
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::munmap(*this - PAGE_SIZE, GetLength() + PAGE_SIZE);
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#else
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#error need to add a case for your CPU
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#endif
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}
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#endif
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private:
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_MappableBuffer(int fd, void *buf, size_t length)
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: MappedPtr(buf, length), fd(fd) { }
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/* File descriptor for the temporary file or ashmem */
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AutoCloseFD fd;
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};
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Mappable *
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MappableDeflate::Create(const char *name, Zip *zip, Zip::Stream *stream)
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{
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MOZ_ASSERT(stream->GetType() == Zip::Stream::DEFLATE);
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_MappableBuffer *buf = _MappableBuffer::Create(name, stream->GetUncompressedSize());
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if (buf)
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return new MappableDeflate(buf, zip, stream);
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return nullptr;
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}
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MappableDeflate::MappableDeflate(_MappableBuffer *buf, Zip *zip,
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Zip::Stream *stream)
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: zip(zip), buffer(buf), zStream(stream->GetZStream(*buf)) { }
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MappableDeflate::~MappableDeflate() { }
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MemoryRange
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MappableDeflate::mmap(const void *addr, size_t length, int prot, int flags, off_t offset)
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{
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MOZ_ASSERT(buffer);
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MOZ_ASSERT(!(flags & MAP_SHARED));
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flags |= MAP_PRIVATE;
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/* The deflate stream is uncompressed up to the required offset + length, if
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* it hasn't previously been uncompressed */
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ssize_t missing = offset + length + zStream.avail_out - buffer->GetLength();
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if (missing > 0) {
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uInt avail_out = zStream.avail_out;
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zStream.avail_out = missing;
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if ((*buffer == zStream.next_out) &&
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(inflateInit2(&zStream, -MAX_WBITS) != Z_OK)) {
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ERROR("inflateInit failed: %s", zStream.msg);
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return MemoryRange(MAP_FAILED, 0);
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}
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int ret = inflate(&zStream, Z_SYNC_FLUSH);
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if (ret < 0) {
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ERROR("inflate failed: %s", zStream.msg);
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return MemoryRange(MAP_FAILED, 0);
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}
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if (ret == Z_NEED_DICT) {
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ERROR("zstream requires a dictionary. %s", zStream.msg);
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return MemoryRange(MAP_FAILED, 0);
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}
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zStream.avail_out = avail_out - missing + zStream.avail_out;
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if (ret == Z_STREAM_END) {
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if (inflateEnd(&zStream) != Z_OK) {
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ERROR("inflateEnd failed: %s", zStream.msg);
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return MemoryRange(MAP_FAILED, 0);
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}
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if (zStream.total_out != buffer->GetLength()) {
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ERROR("File not fully uncompressed! %ld / %d", zStream.total_out,
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static_cast<unsigned int>(buffer->GetLength()));
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return MemoryRange(MAP_FAILED, 0);
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}
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}
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}
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#if defined(ANDROID) && defined(__arm__)
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if (prot & PROT_EXEC) {
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/* We just extracted data that may be executed in the future.
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* We thus need to ensure Instruction and Data cache coherency. */
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DEBUG_LOG("cacheflush(%p, %p)", *buffer + offset, *buffer + (offset + length));
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cacheflush(reinterpret_cast<uintptr_t>(*buffer + offset),
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reinterpret_cast<uintptr_t>(*buffer + (offset + length)), 0);
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}
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#endif
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return MemoryRange(buffer->mmap(addr, length, prot, flags, offset), length);
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}
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void
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MappableDeflate::finalize()
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{
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/* Free zlib internal buffers */
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inflateEnd(&zStream);
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/* Free decompression buffer */
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buffer = nullptr;
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/* Remove reference to Zip archive */
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zip = nullptr;
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}
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size_t
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MappableDeflate::GetLength() const
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{
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return buffer->GetLength();
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}
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