Stop using chrome-sandbox to determine real pids

content/browser/renderer_host/sandbox_ipc_linux.cc

Index: content/browser/renderer_host/sandbox_ipc_linux.cc
diff --git a/content/browser/renderer_host/sandbox_ipc_linux.cc b/content/browser/renderer_host/sandbox_ipc_linux.cc
index ad1747e01736ec41d009c825a9562f8b3b8708d0..aec32c0e9c6a290f606b00503ec43c331d0afa4f 100644
--- a/content/browser/renderer_host/sandbox_ipc_linux.cc
+++ b/content/browser/renderer_host/sandbox_ipc_linux.cc
@@ -158,6 +158,9 @@ void SandboxIPCProcess::Run() {
   pfds[1].fd = browser_socket_;
   pfds[1].events = POLLIN;
 
+  if (!UnixDomainSocket::EnableReceiveProcessId(browser_socket_))
+    LOG(FATAL) << "failed to enable receiving PIDs";
+
   int failed_polls = 0;
   for (;;) {
     const int r = HANDLE_EINTR(poll(pfds, 2, -1 /* no timeout */));
@@ -187,6 +190,7 @@ void SandboxIPCProcess::Run() {
 
 void SandboxIPCProcess::HandleRequestFromRenderer(int fd) {
   std::vector<int> fds;
+  base::ProcessId sender_pid;
 
   // A FontConfigIPC::METHOD_MATCH message could be kMaxFontFamilyLength
   // bytes long (this is the largest message type).
@@ -194,7 +198,8 @@ void SandboxIPCProcess::HandleRequestFromRenderer(int fd) {
   // error for a maximum length message.
   char buf[FontConfigIPC::kMaxFontFamilyLength + 128];
 
-  const ssize_t len = UnixDomainSocket::RecvMsg(fd, buf, sizeof(buf), &fds);
+  const ssize_t len =
+      UnixDomainSocket::RecvMsgWithPid(fd, buf, sizeof(buf), &fds, &sender_pid);
   if (len == -1) {
     // TODO: should send an error reply, or the sender might block forever.
     NOTREACHED() << "Sandbox host message is larger than kMaxFontFamilyLength";
@@ -226,6 +231,8 @@ void SandboxIPCProcess::HandleRequestFromRenderer(int fd) {
     HandleMakeSharedMemorySegment(fd, pickle, iter, fds);
   } else if (kind == LinuxSandbox::METHOD_MATCH_WITH_FALLBACK) {
     HandleMatchWithFallback(fd, pickle, iter, fds);
+  } else if (kind == LinuxSandbox::METHOD_GET_REAL_PID) {
+    HandleGetRealPid(fd, pickle, iter, fds, sender_pid);
   }
 
 error:
@@ -613,6 +620,29 @@ void SandboxIPCProcess::HandleMatchWithFallback(int fd,
   }
 }
 
+void SandboxIPCProcess::HandleGetRealPid(int fd,
+                                         const Pickle& pickle,
+                                         PickleIterator iter,
+                                         std::vector<int>& fds,
+                                         base::ProcessId sender_pid) {
+  if (fds.size() != 2)
+    return;
+
+  bool return_pid;
+  if (!iter.ReadBool(&return_pid))
+    return;
+
+  // Write it to the zygote process.
+  const ssize_t written =
+      HANDLE_EINTR(write(fds[1], &sender_pid, sizeof(sender_pid)));
+  if (written != sizeof(sender_pid))
+    LOG(ERROR) << "Failed to write real pid to zygote";
+
+  Pickle reply;
+  reply.WriteInt(return_pid ? sender_pid : 0);
+  SendRendererReply(fds, reply, -1);
+}
+
 void SandboxIPCProcess::SendRendererReply(const std::vector<int>& fds,
                                           const Pickle& reply,
                                           int reply_fd) {