media: Verify CDM Host files

content/common/media/cdm_host_files.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_COMMON_MEDIA_CDM_HOST_FILES_H_
+#define CONTENT_COMMON_MEDIA_CDM_HOST_FILES_H_
+
+#include <map>
+#include <memory>
+#include <vector>
+
+#include "base/files/file.h"
+#include "base/files/file_path.h"
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "base/native_library.h"
+#include "base/path_service.h"
+#include "build/build_config.h"
+#include "content/common/media/cdm_host_file.h"
+#include "content/common/pepper_plugin_list.h"
+#include "content/public/common/pepper_plugin_info.h"
+#include "media/cdm/api/content_decryption_module_ext.h"
+#include "media/cdm/cdm_paths.h"
+
+// On systems that use the zygote process to spawn child processes, we must
+// open files in the zygote process.
+#if defined(OS_POSIX) && !defined(OS_NACL) && !defined(OS_MACOSX) && \
+    !defined(OS_ANDROID)
+#define POSIX_WITH_ZYGOTE 1
+#endif
+
+namespace base {
+class FilePath;
+}
+
+namespace content {
+
+// Manages all CDM host files.
+class CdmHostFiles {
+ public:
+  CdmHostFiles();
+  ~CdmHostFiles();
+
+#if defined(POSIX_WITH_ZYGOTE)
+  // Opens CDM host files for all registered CDMs and set the global
+  // CdmHostFiles instance.  On any failure, the global instance will not be
+  // set and no file will be left open.
+  static void CreateGlobalInstance();
+
+  // Takes and returns the global CdmHostFiles instance. The return value could
+  // be nullptr if CreateGlobalInstance() failed.
+  static std::unique_ptr<CdmHostFiles> TakeGlobalInstance();
+#endif
+
+  // Opens CDM host files for the CDM adapter at |cdm_adapter_path| and returns
+  // the created CdmHostFiles instance. Returns nullptr if any of the files
+  // cannot be opened, in which case no file will be left open.
+  static std::unique_ptr<CdmHostFiles> Create(
+      const base::FilePath& cdm_adapter_path);
+
+  // Verifies |cdm_adapter_path| CDM files by calling the function exported
+  // by the CDM. If unexpected error happens, all files will be closed.
+  // Otherwise, the PlatformFiles are passed to the CDM which will close the
+  // files later.
+  // Only returns false if the CDM returns false (when there's an immediate
+  // failure). Otherwise always returns true for backward compatibility, e.g.
+  // when using an old CDM which doesn't implement the verification API.
+  bool VerifyFiles(base::NativeLibrary cdm_adapter_library,
+                   const base::FilePath& cdm_adapter_path);
+
+ private:
+#if defined(POSIX_WITH_ZYGOTE)
+  // Opens all common files and CDM specific files for all registered CDMs.
+  bool OpenFilesForAllRegisteredCdms();
+#endif
+
+  // Opens all common files and CDM specific files for the CDM adapter
+  // registered at |cdm_adapter_path|.
+  bool OpenFiles(const base::FilePath& cdm_adapter_path);
+
+  // Opens common CDM host files shared by all CDMs. Upon failure, close all
+  // files opened.
+  bool OpenCommonFiles();
+
+  // Opens CDM specific files for the CDM adapter registered at
+  // |cdm_adapter_path|. Returns whether all CDM specific files are opened.
+  // Upon failure, close all files opened.
+  bool OpenCdmFiles(const base::FilePath& cdm_adapter_path);
+
+  // Fills |cdm_host_files| with common and CDM specific files for
+  // |cdm_adapter_path|. The ownership of those files are also transferred.
+  // Returns true upon success where the remaining files will be closed.
+  // Returns false upon any failure and all files will be closed.
+  bool TakePlatformFiles(const base::FilePath& cdm_adapter_path,
+                         std::vector<cdm::HostFile>* cdm_host_files);
+
+  void CloseAllFiles();
+
+  using ScopedFileVector = std::vector<std::unique_ptr<CdmHostFile>>;
+  ScopedFileVector common_files_;
+  std::map<base::FilePath, ScopedFileVector> cdm_specific_files_map_;
+};
+
+// Returns whether the |cdm_adapter_path| corresponds to a known CDM.
+bool IsCdm(const base::FilePath& cdm_adapter_path);
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_MEDIA_CDM_HOST_FILES_H_