1 files changed, 277 insertions, 0 deletions
diff --git a/mozglue/linker/Zip.cpp b/mozglue/linker/Zip.cpp
new file mode 100644
index 0000000000..7ecc6b9a74
--- /dev/null
+++ b/mozglue/linker/Zip.cpp
@@ -0,0 +1,277 @@
+/* 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());
+  }
+}