xpcom/components/nsNativeModuleLoader.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/.
 * This Original Code has been modified by IBM Corporation.
 * Modifications made by IBM described herein are
 * Copyright (c) International Business Machines
 * Corporation, 2000
 *
 * Modifications to Mozilla code or documentation
 * identified per MPL Section 3.3
 *
 * Date             Modified by     Description of modification
 * 04/20/2000       IBM Corp.      Added PR_CALLBACK for Optlink use in OS2
 */

#include "nsNativeModuleLoader.h"

#include "mozilla/Logging.h"
#include "prinit.h"
#include "prerror.h"

#include "nsComponentManager.h"
#include "ManifestParser.h" // for LogMessage
#include "nsCRTGlue.h"
#include "nsThreadUtils.h"
#include "nsTraceRefcnt.h"

#include "nsIFile.h"
#include "mozilla/WindowsDllBlocklist.h"

#ifdef XP_WIN
#include <windows.h>
#endif

#ifdef XP_MACOSX
#include <signal.h>
#endif

#ifdef DEBUG
#define IMPLEMENT_BREAK_AFTER_LOAD
#endif

using namespace mozilla;

static LazyLogModule sNativeModuleLoaderLog("nsNativeModuleLoader");
#define LOG(level, args) MOZ_LOG(sNativeModuleLoaderLog, level, args)

nsresult
nsNativeModuleLoader::Init()
{
  MOZ_ASSERT(NS_IsMainThread(), "Startup not on main thread?");
  LOG(LogLevel::Debug, ("nsNativeModuleLoader::Init()"));
  return NS_OK;
}

class LoadModuleMainThreadRunnable : public Runnable
{
public:
  LoadModuleMainThreadRunnable(nsNativeModuleLoader* aLoader,
                               FileLocation& aFile)
    : mManager(nsComponentManagerImpl::gComponentManager)
    , mLoader(aLoader)
    , mFile(aFile)
    , mResult(nullptr)
  {
  }

  NS_IMETHOD Run() override
  {
    mResult = mLoader->LoadModule(mFile);
    return NS_OK;
  }

  RefPtr<nsComponentManagerImpl> mManager;
  nsNativeModuleLoader* mLoader;
  FileLocation mFile;
  const mozilla::Module* mResult;
};

const mozilla::Module*
nsNativeModuleLoader::LoadModule(FileLocation& aFile)
{
  if (aFile.IsZip()) {
    NS_ERROR("Binary components cannot be loaded from JARs");
    return nullptr;
  }
  nsCOMPtr<nsIFile> file = aFile.GetBaseFile();
  nsresult rv;

  if (!NS_IsMainThread()) {
    // If this call is off the main thread, synchronously proxy it
    // to the main thread.
    RefPtr<LoadModuleMainThreadRunnable> r =
      new LoadModuleMainThreadRunnable(this, aFile);
    NS_DispatchToMainThread(r, NS_DISPATCH_SYNC);
    return r->mResult;
  }

  nsCOMPtr<nsIHashable> hashedFile(do_QueryInterface(file));
  if (!hashedFile) {
    NS_ERROR("nsIFile is not nsIHashable");
    return nullptr;
  }

  nsAutoCString filePath;
  file->GetNativePath(filePath);

  NativeLoadData data;

  if (mLibraries.Get(hashedFile, &data)) {
    NS_ASSERTION(data.mModule, "Corrupt mLibraries hash");
    LOG(LogLevel::Debug,
        ("nsNativeModuleLoader::LoadModule(\"%s\") - found in cache",
         filePath.get()));
    return data.mModule;
  }

  // We haven't loaded this module before
  {
#ifdef HAS_DLL_BLOCKLIST
    AutoSetXPCOMLoadOnMainThread guard;
#endif
    rv = file->Load(&data.mLibrary);
  }

  if (NS_FAILED(rv)) {
    char errorMsg[1024] = "<unknown; can't get error from NSPR>";

    if (PR_GetErrorTextLength() < (int)sizeof(errorMsg)) {
      PR_GetErrorText(errorMsg);
    }

    LogMessage("Failed to load native module at path '%s': (%lx) %s",
               filePath.get(), rv, errorMsg);

    return nullptr;
  }

#ifdef IMPLEMENT_BREAK_AFTER_LOAD
  nsAutoCString leafName;
  file->GetNativeLeafName(leafName);

  char* env = getenv("XPCOM_BREAK_ON_LOAD");
  char* blist;
  if (env && *env && (blist = strdup(env))) {
    char* nextTok = blist;
    while (char* token = NS_strtok(":", &nextTok)) {
      if (leafName.Find(token, true) != kNotFound) {
        NS_BREAK();
      }
    }

    free(blist);
  }
#endif

  void* module = PR_FindSymbol(data.mLibrary, "NSModule");
  if (!module) {
    LogMessage("Native module at path '%s' doesn't export symbol `NSModule`.",
               filePath.get());
    PR_UnloadLibrary(data.mLibrary);
    return nullptr;
  }

  data.mModule = *(mozilla::Module const* const*)module;
  if (mozilla::Module::kVersion != data.mModule->mVersion) {
    LogMessage("Native module at path '%s' is incompatible with this version of Firefox, has version %i, expected %i.",
               filePath.get(), data.mModule->mVersion,
               mozilla::Module::kVersion);
    PR_UnloadLibrary(data.mLibrary);
    return nullptr;
  }

  mLibraries.Put(hashedFile, data); // infallible
  return data.mModule;
}

void
nsNativeModuleLoader::UnloadLibraries()
{
  MOZ_ASSERT(NS_IsMainThread(), "Shutdown not on main thread?");

  for (auto iter = mLibraries.Iter(); !iter.Done(); iter.Next()) {
    NativeLoadData& loadData = iter.Data();
    loadData.mModule = nullptr;
  }

  for (auto iter = mLibraries.Iter(); !iter.Done(); iter.Next()) {
    if (MOZ_LOG_TEST(sNativeModuleLoaderLog, LogLevel::Debug)) {
      nsIHashable* hashedFile = iter.Key();
      nsCOMPtr<nsIFile> file(do_QueryInterface(hashedFile));

      nsAutoCString filePath;
      file->GetNativePath(filePath);

      LOG(LogLevel::Debug,
          ("nsNativeModuleLoader::UnloaderFunc(\"%s\")", filePath.get()));
    }

#ifdef NS_BUILD_REFCNT_LOGGING
    nsTraceRefcnt::SetActivityIsLegal(false);
#endif

#if 0
    // XXXbsmedberg: do this as soon as the static-destructor crash(es)
    // are fixed
    NativeLoadData& loadData = iter.Data();
    PRStatus ret = PR_UnloadLibrary(loadData.mLibrary);
    NS_ASSERTION(ret == PR_SUCCESS, "Failed to unload library");
#endif

#ifdef NS_BUILD_REFCNT_LOGGING
    nsTraceRefcnt::SetActivityIsLegal(true);
#endif

    iter.Remove();
  }
}