The Tor Browser: comparison mozglue/linker/Zip.cpp

--1:000000000000
+:8fe4452f2f47
+/* 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"
+mozilla::TemporaryRef<Zip>
+Zip::Create(const char *filename)
+{
+/* Open and map the file in memory */
+AutoCloseFD fd(open(filename, O_RDONLY));
+if (fd == -1) {
+LOG("Error opening %s: %s", filename, strerror(errno));
+return nullptr;
+}
+struct stat st;
+if (fstat(fd, &st) == -1) {
+LOG("Error stating %s: %s", filename, strerror(errno));
+return nullptr;
+}
+size_t size = st.st_size;
+if (size <= sizeof(CentralDirectoryEnd)) {
+LOG("Error reading %s: too short", filename);
+return nullptr;
+}
+void *mapped = mmap(nullptr, size, PROT_READ, MAP_SHARED, fd, 0);
+if (mapped == MAP_FAILED) {
+LOG("Error mmapping %s: %s", filename, strerror(errno));
+return nullptr;
+}
+DEBUG_LOG("Mapped %s @%p", filename, mapped);
+return Create(filename, mapped, size);
+}
+mozilla::TemporaryRef<Zip>
+Zip::Create(const char *filename, void *mapped, size_t size)
+{
+mozilla::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) {
+LOG("%s - Invalid zip", filename);
+return nullptr;
+}
+ZipCollection::Singleton.Register(zip);
+return zip;
+}
+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)
+{
+// 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()
+{
+ZipCollection::Forget(this);
+if (name) {
+munmap(mapped, size);
+DEBUG_LOG("Unmapped %s @%p", name, mapped);
+free(name);
+}
+}
+bool
+Zip::GetStream(const char *path, Zip::Stream *out) const
+{
+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->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) {
+LOG("%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->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) {
+LOG("%s - Couldn't find end of central directory record", name);
+return nullptr;
+}
+entries = DirectoryEntry::validate(static_cast<const char *>(mapped)
++ end->offset);
+if (!entries) {
+LOG("%s - Couldn't find central directory record", name);
+}
+return entries;
+}
+ZipCollection ZipCollection::Singleton;
+mozilla::TemporaryRef<Zip>
+ZipCollection::GetZip(const char *path)
+{
+/* Search the list of Zips we already have for a match */
+for (std::vector<Zip *>::iterator it = Singleton.zips.begin();
+it < Singleton.zips.end(); ++it) {
+if ((*it)->GetName() && (strcmp((*it)->GetName(), path) == 0))
+return *it;
+}
+return Zip::Create(path);
+}
+void
+ZipCollection::Register(Zip *zip)
+{
+Singleton.zips.push_back(zip);
+}
+void
+ZipCollection::Forget(Zip *zip)
+{
+DEBUG_LOG("ZipCollection::Forget(\"%s\")", zip->GetName());
+std::vector<Zip *>::iterator 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());
+}
+}

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comparison: mozglue/linker/Zip.cpp

mozglue/linker/Zip.cpp