1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mozglue/linker/Zip.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,213 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.6 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#include <sys/mman.h>
1.9 +#include <sys/stat.h>
1.10 +#include <fcntl.h>
1.11 +#include <errno.h>
1.12 +#include <unistd.h>
1.13 +#include <cstdlib>
1.14 +#include <algorithm>
1.15 +#include "Logging.h"
1.16 +#include "Zip.h"
1.17 +
1.18 +mozilla::TemporaryRef<Zip>
1.19 +Zip::Create(const char *filename)
1.20 +{
1.21 + /* Open and map the file in memory */
1.22 + AutoCloseFD fd(open(filename, O_RDONLY));
1.23 + if (fd == -1) {
1.24 + LOG("Error opening %s: %s", filename, strerror(errno));
1.25 + return nullptr;
1.26 + }
1.27 + struct stat st;
1.28 + if (fstat(fd, &st) == -1) {
1.29 + LOG("Error stating %s: %s", filename, strerror(errno));
1.30 + return nullptr;
1.31 + }
1.32 + size_t size = st.st_size;
1.33 + if (size <= sizeof(CentralDirectoryEnd)) {
1.34 + LOG("Error reading %s: too short", filename);
1.35 + return nullptr;
1.36 + }
1.37 + void *mapped = mmap(nullptr, size, PROT_READ, MAP_SHARED, fd, 0);
1.38 + if (mapped == MAP_FAILED) {
1.39 + LOG("Error mmapping %s: %s", filename, strerror(errno));
1.40 + return nullptr;
1.41 + }
1.42 + DEBUG_LOG("Mapped %s @%p", filename, mapped);
1.43 +
1.44 + return Create(filename, mapped, size);
1.45 +}
1.46 +
1.47 +mozilla::TemporaryRef<Zip>
1.48 +Zip::Create(const char *filename, void *mapped, size_t size)
1.49 +{
1.50 + mozilla::RefPtr<Zip> zip = new Zip(filename, mapped, size);
1.51 +
1.52 + // If neither the first Local File entry nor central directory entries
1.53 + // have been found, the zip was invalid.
1.54 + if (!zip->nextFile && !zip->entries) {
1.55 + LOG("%s - Invalid zip", filename);
1.56 + return nullptr;
1.57 + }
1.58 +
1.59 + ZipCollection::Singleton.Register(zip);
1.60 + return zip;
1.61 +}
1.62 +
1.63 +Zip::Zip(const char *filename, void *mapped, size_t size)
1.64 +: name(filename ? strdup(filename) : nullptr)
1.65 +, mapped(mapped)
1.66 +, size(size)
1.67 +, nextFile(LocalFile::validate(mapped)) // first Local File entry
1.68 +, nextDir(nullptr)
1.69 +, entries(nullptr)
1.70 +{
1.71 + // If the first local file entry couldn't be found (which can happen
1.72 + // with optimized jars), check the first central directory entry.
1.73 + if (!nextFile)
1.74 + GetFirstEntry();
1.75 +}
1.76 +
1.77 +Zip::~Zip()
1.78 +{
1.79 + ZipCollection::Forget(this);
1.80 + if (name) {
1.81 + munmap(mapped, size);
1.82 + DEBUG_LOG("Unmapped %s @%p", name, mapped);
1.83 + free(name);
1.84 + }
1.85 +}
1.86 +
1.87 +bool
1.88 +Zip::GetStream(const char *path, Zip::Stream *out) const
1.89 +{
1.90 + DEBUG_LOG("%s - GetFile %s", name, path);
1.91 + /* Fast path: if the Local File header on store matches, we can return the
1.92 + * corresponding stream right away.
1.93 + * However, the Local File header may not contain enough information, in
1.94 + * which case the 3rd bit on the generalFlag is set. Unfortunately, this
1.95 + * bit is also set in some archives even when we do have the data (most
1.96 + * notably the android packages as built by the Mozilla build system).
1.97 + * So instead of testing the generalFlag bit, only use the fast path when
1.98 + * we haven't read the central directory entries yet, and when the
1.99 + * compressed size as defined in the header is not filled (which is a
1.100 + * normal condition for the bit to be set). */
1.101 + if (nextFile && nextFile->GetName().Equals(path) &&
1.102 + !entries && (nextFile->compressedSize != 0)) {
1.103 + DEBUG_LOG("%s - %s was next file: fast path", name, path);
1.104 + /* Fill Stream info from Local File header content */
1.105 + const char *data = reinterpret_cast<const char *>(nextFile->GetData());
1.106 + out->compressedBuf = data;
1.107 + out->compressedSize = nextFile->compressedSize;
1.108 + out->uncompressedSize = nextFile->uncompressedSize;
1.109 + out->type = static_cast<Stream::Type>(uint16_t(nextFile->compression));
1.110 +
1.111 + /* Find the next Local File header. It is usually simply following the
1.112 + * compressed stream, but in cases where the 3rd bit of the generalFlag
1.113 + * is set, there is a Data Descriptor header before. */
1.114 + data += nextFile->compressedSize;
1.115 + if ((nextFile->generalFlag & 0x8) && DataDescriptor::validate(data)) {
1.116 + data += sizeof(DataDescriptor);
1.117 + }
1.118 + nextFile = LocalFile::validate(data);
1.119 + return true;
1.120 + }
1.121 +
1.122 + /* If the directory entry we have in store doesn't match, scan the Central
1.123 + * Directory for the entry corresponding to the given path */
1.124 + if (!nextDir || !nextDir->GetName().Equals(path)) {
1.125 + const DirectoryEntry *entry = GetFirstEntry();
1.126 + DEBUG_LOG("%s - Scan directory entries in search for %s", name, path);
1.127 + while (entry && !entry->GetName().Equals(path)) {
1.128 + entry = entry->GetNext();
1.129 + }
1.130 + nextDir = entry;
1.131 + }
1.132 + if (!nextDir) {
1.133 + DEBUG_LOG("%s - Couldn't find %s", name, path);
1.134 + return false;
1.135 + }
1.136 +
1.137 + /* Find the Local File header corresponding to the Directory entry that
1.138 + * was found. */
1.139 + nextFile = LocalFile::validate(static_cast<const char *>(mapped)
1.140 + + nextDir->offset);
1.141 + if (!nextFile) {
1.142 + LOG("%s - Couldn't find the Local File header for %s", name, path);
1.143 + return false;
1.144 + }
1.145 +
1.146 + /* Fill Stream info from Directory entry content */
1.147 + const char *data = reinterpret_cast<const char *>(nextFile->GetData());
1.148 + out->compressedBuf = data;
1.149 + out->compressedSize = nextDir->compressedSize;
1.150 + out->uncompressedSize = nextDir->uncompressedSize;
1.151 + out->type = static_cast<Stream::Type>(uint16_t(nextDir->compression));
1.152 +
1.153 + /* Store the next directory entry */
1.154 + nextDir = nextDir->GetNext();
1.155 + nextFile = nullptr;
1.156 + return true;
1.157 +}
1.158 +
1.159 +const Zip::DirectoryEntry *
1.160 +Zip::GetFirstEntry() const
1.161 +{
1.162 + if (entries)
1.163 + return entries;
1.164 +
1.165 + const CentralDirectoryEnd *end = nullptr;
1.166 + const char *_end = static_cast<const char *>(mapped) + size
1.167 + - sizeof(CentralDirectoryEnd);
1.168 +
1.169 + /* Scan for the Central Directory End */
1.170 + for (; _end > mapped && !end; _end--)
1.171 + end = CentralDirectoryEnd::validate(_end);
1.172 + if (!end) {
1.173 + LOG("%s - Couldn't find end of central directory record", name);
1.174 + return nullptr;
1.175 + }
1.176 +
1.177 + entries = DirectoryEntry::validate(static_cast<const char *>(mapped)
1.178 + + end->offset);
1.179 + if (!entries) {
1.180 + LOG("%s - Couldn't find central directory record", name);
1.181 + }
1.182 + return entries;
1.183 +}
1.184 +
1.185 +ZipCollection ZipCollection::Singleton;
1.186 +
1.187 +mozilla::TemporaryRef<Zip>
1.188 +ZipCollection::GetZip(const char *path)
1.189 +{
1.190 + /* Search the list of Zips we already have for a match */
1.191 + for (std::vector<Zip *>::iterator it = Singleton.zips.begin();
1.192 + it < Singleton.zips.end(); ++it) {
1.193 + if ((*it)->GetName() && (strcmp((*it)->GetName(), path) == 0))
1.194 + return *it;
1.195 + }
1.196 + return Zip::Create(path);
1.197 +}
1.198 +
1.199 +void
1.200 +ZipCollection::Register(Zip *zip)
1.201 +{
1.202 + Singleton.zips.push_back(zip);
1.203 +}
1.204 +
1.205 +void
1.206 +ZipCollection::Forget(Zip *zip)
1.207 +{
1.208 + DEBUG_LOG("ZipCollection::Forget(\"%s\")", zip->GetName());
1.209 + std::vector<Zip *>::iterator it = std::find(Singleton.zips.begin(),
1.210 + Singleton.zips.end(), zip);
1.211 + if (*it == zip) {
1.212 + Singleton.zips.erase(it);
1.213 + } else {
1.214 + DEBUG_LOG("ZipCollection::Forget: didn't find \"%s\" in bookkeeping", zip->GetName());
1.215 + }
1.216 +}
