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-rw-r--r--mozglue/linker/Zip.cpp277
1 files changed, 277 insertions, 0 deletions
diff --git a/mozglue/linker/Zip.cpp b/mozglue/linker/Zip.cpp
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+++ b/mozglue/linker/Zip.cpp
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <cstdlib>
+#include <algorithm>
+#include "Logging.h"
+#include "Zip.h"
+
+already_AddRefed<Zip> Zip::Create(const char* filename) {
+ /* Open and map the file in memory */
+ AutoCloseFD fd(open(filename, O_RDONLY));
+ if (fd == -1) {
+ ERROR("Error opening %s: %s", filename, strerror(errno));
+ return nullptr;
+ }
+ struct stat st;
+ if (fstat(fd, &st) == -1) {
+ ERROR("Error stating %s: %s", filename, strerror(errno));
+ return nullptr;
+ }
+ size_t size = st.st_size;
+ if (size <= sizeof(CentralDirectoryEnd)) {
+ ERROR("Error reading %s: too short", filename);
+ return nullptr;
+ }
+ void* mapped = mmap(nullptr, size, PROT_READ, MAP_SHARED, fd, 0);
+ if (mapped == MAP_FAILED) {
+ ERROR("Error mmapping %s: %s", filename, strerror(errno));
+ return nullptr;
+ }
+ DEBUG_LOG("Mapped %s @%p", filename, mapped);
+
+ return Create(filename, mapped, size);
+}
+
+already_AddRefed<Zip> Zip::Create(const char* filename, void* mapped,
+ size_t size) {
+ RefPtr<Zip> zip = new Zip(filename, mapped, size);
+
+ // If neither the first Local File entry nor central directory entries
+ // have been found, the zip was invalid.
+ if (!zip->nextFile && !zip->entries) {
+ ERROR("%s - Invalid zip", filename);
+ return nullptr;
+ }
+
+ ZipCollection::Singleton.Register(zip);
+ return zip.forget();
+}
+
+Zip::Zip(const char* filename, void* mapped, size_t size)
+ : name(filename ? strdup(filename) : nullptr),
+ mapped(mapped),
+ size(size),
+ nextFile(LocalFile::validate(mapped)) // first Local File entry
+ ,
+ nextDir(nullptr),
+ entries(nullptr) {
+ pthread_mutex_init(&mutex, nullptr);
+ // If the first local file entry couldn't be found (which can happen
+ // with optimized jars), check the first central directory entry.
+ if (!nextFile) GetFirstEntry();
+}
+
+Zip::~Zip() {
+ if (name) {
+ munmap(mapped, size);
+ DEBUG_LOG("Unmapped %s @%p", name, mapped);
+ free(name);
+ }
+ pthread_mutex_destroy(&mutex);
+}
+
+bool Zip::GetStream(const char* path, Zip::Stream* out) const {
+ AutoLock lock(&mutex);
+
+ DEBUG_LOG("%s - GetFile %s", name, path);
+ /* Fast path: if the Local File header on store matches, we can return the
+ * corresponding stream right away.
+ * However, the Local File header may not contain enough information, in
+ * which case the 3rd bit on the generalFlag is set. Unfortunately, this
+ * bit is also set in some archives even when we do have the data (most
+ * notably the android packages as built by the Mozilla build system).
+ * So instead of testing the generalFlag bit, only use the fast path when
+ * we haven't read the central directory entries yet, and when the
+ * compressed size as defined in the header is not filled (which is a
+ * normal condition for the bit to be set). */
+ if (nextFile && nextFile->GetName().Equals(path) && !entries &&
+ (nextFile->compressedSize != 0)) {
+ DEBUG_LOG("%s - %s was next file: fast path", name, path);
+ /* Fill Stream info from Local File header content */
+ const char* data = reinterpret_cast<const char*>(nextFile->GetData());
+ out->compressedBuf = data;
+ out->compressedSize = nextFile->compressedSize;
+ out->uncompressedSize = nextFile->uncompressedSize;
+ out->CRC32 = nextFile->CRC32;
+ out->type = static_cast<Stream::Type>(uint16_t(nextFile->compression));
+
+ /* Find the next Local File header. It is usually simply following the
+ * compressed stream, but in cases where the 3rd bit of the generalFlag
+ * is set, there is a Data Descriptor header before. */
+ data += nextFile->compressedSize;
+ if ((nextFile->generalFlag & 0x8) && DataDescriptor::validate(data)) {
+ data += sizeof(DataDescriptor);
+ }
+ nextFile = LocalFile::validate(data);
+ return true;
+ }
+
+ /* If the directory entry we have in store doesn't match, scan the Central
+ * Directory for the entry corresponding to the given path */
+ if (!nextDir || !nextDir->GetName().Equals(path)) {
+ const DirectoryEntry* entry = GetFirstEntry();
+ DEBUG_LOG("%s - Scan directory entries in search for %s", name, path);
+ while (entry && !entry->GetName().Equals(path)) {
+ entry = entry->GetNext();
+ }
+ nextDir = entry;
+ }
+ if (!nextDir) {
+ DEBUG_LOG("%s - Couldn't find %s", name, path);
+ return false;
+ }
+
+ /* Find the Local File header corresponding to the Directory entry that
+ * was found. */
+ nextFile =
+ LocalFile::validate(static_cast<const char*>(mapped) + nextDir->offset);
+ if (!nextFile) {
+ ERROR("%s - Couldn't find the Local File header for %s", name, path);
+ return false;
+ }
+
+ /* Fill Stream info from Directory entry content */
+ const char* data = reinterpret_cast<const char*>(nextFile->GetData());
+ out->compressedBuf = data;
+ out->compressedSize = nextDir->compressedSize;
+ out->uncompressedSize = nextDir->uncompressedSize;
+ out->CRC32 = nextDir->CRC32;
+ out->type = static_cast<Stream::Type>(uint16_t(nextDir->compression));
+
+ /* Store the next directory entry */
+ nextDir = nextDir->GetNext();
+ nextFile = nullptr;
+ return true;
+}
+
+const Zip::DirectoryEntry* Zip::GetFirstEntry() const {
+ if (entries) return entries;
+
+ const CentralDirectoryEnd* end = nullptr;
+ const char* _end =
+ static_cast<const char*>(mapped) + size - sizeof(CentralDirectoryEnd);
+
+ /* Scan for the Central Directory End */
+ for (; _end > mapped && !end; _end--)
+ end = CentralDirectoryEnd::validate(_end);
+ if (!end) {
+ ERROR("%s - Couldn't find end of central directory record", name);
+ return nullptr;
+ }
+
+ entries =
+ DirectoryEntry::validate(static_cast<const char*>(mapped) + end->offset);
+ if (!entries) {
+ ERROR("%s - Couldn't find central directory record", name);
+ }
+ return entries;
+}
+
+bool Zip::VerifyCRCs() const {
+ AutoLock lock(&mutex);
+
+ for (const DirectoryEntry* entry = GetFirstEntry(); entry;
+ entry = entry->GetNext()) {
+ const LocalFile* file =
+ LocalFile::validate(static_cast<const char*>(mapped) + entry->offset);
+ uint32_t crc = crc32(0, nullptr, 0);
+
+ DEBUG_LOG("%.*s: crc=%08x", int(entry->filenameSize),
+ reinterpret_cast<const char*>(entry) + sizeof(*entry),
+ uint32_t(entry->CRC32));
+
+ if (entry->compression == Stream::Type::STORE) {
+ crc = crc32(crc, static_cast<const uint8_t*>(file->GetData()),
+ entry->compressedSize);
+ DEBUG_LOG(" STORE size=%d crc=%08x", int(entry->compressedSize), crc);
+
+ } else if (entry->compression == Stream::Type::DEFLATE) {
+ z_stream zstream;
+ Bytef buffer[1024];
+ zstream.avail_in = entry->compressedSize;
+ zstream.next_in =
+ reinterpret_cast<Bytef*>(const_cast<void*>(file->GetData()));
+ zstream.zalloc = nullptr;
+ zstream.zfree = nullptr;
+ zstream.opaque = nullptr;
+
+ if (inflateInit2(&zstream, -MAX_WBITS) != Z_OK) {
+ return false;
+ }
+
+ for (;;) {
+ zstream.avail_out = sizeof(buffer);
+ zstream.next_out = buffer;
+
+ int ret = inflate(&zstream, Z_SYNC_FLUSH);
+ crc = crc32(crc, buffer, sizeof(buffer) - zstream.avail_out);
+
+ if (ret == Z_STREAM_END) {
+ break;
+ } else if (ret != Z_OK) {
+ return false;
+ }
+ }
+
+ inflateEnd(&zstream);
+ DEBUG_LOG(" DEFLATE size=%d crc=%08x", int(zstream.total_out), crc);
+
+ } else {
+ MOZ_ASSERT_UNREACHABLE("Unexpected stream type");
+ continue;
+ }
+
+ if (entry->CRC32 != crc) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+ZipCollection ZipCollection::Singleton;
+
+static pthread_mutex_t sZipCollectionMutex = PTHREAD_MUTEX_INITIALIZER;
+
+already_AddRefed<Zip> ZipCollection::GetZip(const char* path) {
+ {
+ AutoLock lock(&sZipCollectionMutex);
+ /* Search the list of Zips we already have for a match */
+ for (const auto& zip : Singleton.zips) {
+ if (zip->GetName() && (strcmp(zip->GetName(), path) == 0)) {
+ return RefPtr<Zip>(zip).forget();
+ }
+ }
+ }
+ return Zip::Create(path);
+}
+
+void ZipCollection::Register(Zip* zip) {
+ AutoLock lock(&sZipCollectionMutex);
+ DEBUG_LOG("ZipCollection::Register(\"%s\")", zip->GetName());
+ Singleton.zips.push_back(zip);
+}
+
+void ZipCollection::Forget(const Zip* zip) {
+ AutoLock lock(&sZipCollectionMutex);
+ if (zip->refCount() > 1) {
+ // Someone has acquired a reference before we had acquired the lock,
+ // ignore this request.
+ return;
+ }
+ DEBUG_LOG("ZipCollection::Forget(\"%s\")", zip->GetName());
+ const auto it = std::find(Singleton.zips.begin(), Singleton.zips.end(), zip);
+ if (*it == zip) {
+ Singleton.zips.erase(it);
+ } else {
+ DEBUG_LOG("ZipCollection::Forget: didn't find \"%s\" in bookkeeping",
+ zip->GetName());
+ }
+}