The Tor Browser: mozglue/linker/Zip.cpp@6474c204b198 (annotated)

mozglue/linker/Zip.cpp@6474c204b198 (annotated)

mozglue/linker/Zip.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* 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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mozglue/linker/Zip.cpp@6474c204b198 (annotated)

mozglue/linker/Zip.cpp