GpuArcVideoService

components/arc/arc_bridge_bootstrap.cc

 // Copyright 2015 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 "components/arc/arc_bridge_bootstrap.h"
 
 #include <fcntl.h>
 #include <grp.h>
 #include <unistd.h>
 
@@ skipping 14 matching lines @@
 #include "ipc/unix_domain_socket_util.h"
 #include "mojo/edk/embedder/embedder.h"
 #include "mojo/edk/embedder/platform_channel_pair.h"
 #include "mojo/edk/embedder/platform_channel_utils_posix.h"
 #include "mojo/edk/embedder/platform_handle_vector.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
 namespace arc {
 
+// This assumes all video accelerator clients are from the same namespace and
+// the max pid of the said namespace is kPidMask.
+base::ProcessHandle RemapChildPid(uint32_t pid) {

[Luis Héctor Chávez, 2016/03/28 16:01:27]

nit: s/uint32_t/base::ProcessHandle/ in all this.

[kcwu, 2016/03/28 18:16:49]

Done.

+  uint32_t kPidBase = 0x3DE0EA7C;  // arbitrarily chosen.
+  uint32_t kPidMask = 0x7fff;      // the default, 32k.
+  return kPidBase + (pid & kPidMask);
+}
+
 namespace {
 
-// We do not know the PID of ARC, since Chrome does not create it directly.
-// Since Mojo in POSIX does not use the child PID except as an unique
-// identifier for the routing table, rather than doing a lot of plumbing in the
-// whole system to get the correct PID, just use an arbitrary number that will
-// never be used by a legitimate process. Chrome OS assigns unassigned PIDs
-// sequentially until it reaches a certain maximum value (Chrome OS uses the
-// default value of 32k), at which point it loops around to zero. An arbitrary
-// number larger than the maximum should be safe.
-const pid_t kArcPid = 0x3DE0EA7C;
-
 const base::FilePath::CharType kArcBridgeSocketPath[] =
     FILE_PATH_LITERAL("/var/run/chrome/arc_bridge.sock");
 
 const char kArcBridgeSocketGroup[] = "arc-bridge";
 
 class ArcBridgeBootstrapImpl : public ArcBridgeBootstrap {
  public:
   // The possible states of the bootstrap connection.  In the normal flow,
   // the state changes in the following sequence:
   //
@@ skipping 196 matching lines @@
 
 // static
 base::ScopedFD ArcBridgeBootstrapImpl::AcceptInstanceConnection(
     base::ScopedFD socket_fd) {
   int raw_fd = -1;
   if (!IPC::ServerAcceptConnection(socket_fd.get(), &raw_fd)) {
     return base::ScopedFD();
   }
   base::ScopedFD scoped_fd(raw_fd);
 
+  // We do not know the PID of ARC, since Chrome does not create it directly
+  // and it may in the difference namespace. Here we assume the pid is zero
+  // (should not happen in its namespace) and RemapChildPid to safe range (not
+  // conflict in our namespace).
+  const pid_t kArcPid = RemapChildPid(0);

[Luis Héctor Chávez, 2016/03/28 16:01:27]

nit: const base::ProcessHandle

[kcwu, 2016/03/28 18:16:49]

Done.

   mojo::edk::ScopedPlatformHandle child_handle =
       mojo::edk::ChildProcessLaunched(kArcPid);
 
   mojo::edk::ScopedPlatformHandleVectorPtr handles(
       new mojo::edk::PlatformHandleVector{child_handle.release()});
 
   struct iovec iov = {const_cast<char*>(""), 1};
   ssize_t result = mojo::edk::PlatformChannelSendmsgWithHandles(
       mojo::edk::PlatformHandle(scoped_fd.get()), &iov, 1, handles->data(),
       handles->size());
@@ skipping 69 matching lines @@
 
 ArcBridgeBootstrap::ArcBridgeBootstrap() {}
 ArcBridgeBootstrap::~ArcBridgeBootstrap() {}
 
 // static
 scoped_ptr<ArcBridgeBootstrap> ArcBridgeBootstrap::Create() {
   return make_scoped_ptr(new ArcBridgeBootstrapImpl());
 }
 
 }  // namespace arc