Adaptively use temp dir instead of /dev/shm for executable shmem file on Linux

base/file_util.h

 // Copyright (c) 2011 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.
 
 // This file contains utility functions for dealing with the local
 // filesystem.
 
 #ifndef BASE_FILE_UTIL_H_
 #define BASE_FILE_UTIL_H_
 #pragma once
@@ skipping 241 matching lines @@
 
 // Return true if the given directory is empty
 BASE_EXPORT bool IsDirectoryEmpty(const FilePath& dir_path);
 
 // Get the temporary directory provided by the system.
 // WARNING: DON'T USE THIS. If you want to create a temporary file, use one of
 // the functions below.
 BASE_EXPORT bool GetTempDir(FilePath* path);
 // Get a temporary directory for shared memory files.
 // Only useful on POSIX; redirects to GetTempDir() on Windows.
-BASE_EXPORT bool GetShmemTempDir(FilePath* path);
+BASE_EXPORT bool GetShmemTempDir(FilePath* path, bool executable);
 
 // Get the home directory.  This is more complicated than just getenv("HOME")
 // as it knows to fall back on getpwent() etc.
 BASE_EXPORT FilePath GetHomeDir();
 
 // Creates a temporary file. The full path is placed in |path|, and the
 // function returns true if was successful in creating the file. The file will
 // be empty and all handles closed after this function returns.
 BASE_EXPORT bool CreateTemporaryFile(FilePath* path);
 
 // Same as CreateTemporaryFile but the file is created in |dir|.
 BASE_EXPORT bool CreateTemporaryFileInDir(const FilePath& dir,
                                           FilePath* temp_file);
 
 // Create and open a temporary file.  File is opened for read/write.
 // The full path is placed in |path|.
 // Returns a handle to the opened file or NULL if an error occured.
 BASE_EXPORT FILE* CreateAndOpenTemporaryFile(FilePath* path);
 // Like above but for shmem files.  Only useful for POSIX.
-BASE_EXPORT FILE* CreateAndOpenTemporaryShmemFile(FilePath* path);
+// The executable flag says the file needs to support using
+// mprotect with PROT_EXEC after mapping.
+BASE_EXPORT FILE* CreateAndOpenTemporaryShmemFile(FilePath* path,
+                                                  bool executable);
 // Similar to CreateAndOpenTemporaryFile, but the file is created in |dir|.
 BASE_EXPORT FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir,
                                                   FilePath* path);
 
 // Create a new directory. If prefix is provided, the new directory name is in
 // the format of prefixyyyy.
 // NOTE: prefix is ignored in the POSIX implementation.
 // If success, return true and output the full path of the directory created.
 BASE_EXPORT bool CreateNewTempDirectory(const FilePath::StringType& prefix,
                                         FilePath* new_temp_path);
@@ skipping 335 matching lines @@
 BASE_EXPORT bool GetFileSystemType(const FilePath& path, FileSystemType* type);
 #endif
 
 }  // namespace file_util
 
 // Deprecated functions have been moved to this separate header file,
 // which must be included last after all the above definitions.
 #include "base/file_util_deprecated.h"
 
 #endif  // BASE_FILE_UTIL_H_