Hooking MHTML generation to the browser.

base/platform_file_posix.cc

 // 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.
 
 #include "base/platform_file.h"
 
 #include <fcntl.h>
 #include <errno.h>
 #include <sys/stat.h>
 
@@ skipping 173 matching lines @@
 
   info->is_directory = S_ISDIR(file_info.st_mode);
   info->is_symbolic_link = S_ISLNK(file_info.st_mode);
   info->size = file_info.st_size;
   info->last_modified = base::Time::FromTimeT(file_info.st_mtime);
   info->last_accessed = base::Time::FromTimeT(file_info.st_atime);
   info->creation_time = base::Time::FromTimeT(file_info.st_ctime);
   return true;
 }
 
+PlatformFile GetFileHandleForProcess(PlatformFile file,
+                                     ProcessHandle process,
+                                     bool close_source_handle) {
+  return file;

[piman, 2011/06/13 23:19:42]

from the peanut-gallery: this has a race condition.
Imagine something like:
int fd=open("myfile", O_RDONLY);
int remote_fd = GetFileHandleForProcess(fd, remote_process, false);
channel->Send(new MyMessage(FileDescriptor(remote_fd, false)));
close(fd);

Then, since remote_fd==fd, the close(fd) may close remote_fd before the IPC
message gets sent, in which case the receiving process won't receive a valid fd
(or at least not the one it should)

A good way to ensure no race is to always returns a fd that the caller owns:
close_source_handle ? file : dup(file)

And then the caller is responsible for sending a FileDescriptor(remote_fd,
true), avoiding the race in all cases.

[Jay Civelli, 2011/06/14 00:19:27]

Good point!
I moved that code to ipc_platform_file.cc, and this is what it now does.

[piman, 2011/06/14 00:31:23]

Great, LGTM on that.

+}
+
 }  // namespace base