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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()
{
ZipCollection::Forget(this);
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;
}
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 (std::vector<Zip *>::iterator it = Singleton.zips.begin();
it < Singleton.zips.end(); ++it) {
if ((*it)->GetName() && (strcmp((*it)->GetName(), path) == 0)) {
RefPtr<Zip> zip = *it;
return 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(Zip *zip)
{
AutoLock lock(&sZipCollectionMutex);
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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