Always Ignore SIGPIPE for NaCl both in SFI mode and non SFI mode.

components/nacl/loader/nacl_helper_linux.cc

 // Copyright 2013 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.
 
 // A mini-zygote specifically for Native Client.
 
 #include "components/nacl/loader/nacl_helper_linux.h"
 
 #include <errno.h>
 #include <fcntl.h>
@@ skipping 73 matching lines @@
     // it with a dummy.
     const int sandbox_ipc_channel =
         base::GlobalDescriptors::kBaseDescriptor + kSandboxIPCChannel;
 
     ReplaceFDWithDummy(sandbox_ipc_channel);
 
     // Install crash signal handlers before disallowing system calls.
     nacl::nonsfi::InitializeSignalHandler();
   }
 
+  // Always ignore SIGPIPE.  We check the return value of write().

[Mark Seaborn, 2014/05/15 16:21:25]

The "we" here is rather vague (and different from the "we" in the next line :-)
).

How about: Always ignore SIGPIPE, for consistency with other Chrome processes,
and because some IPC code, such as sync_socket_posix.cc, requires this.

[hidehiko, 2014/05/16 08:21:02]

Done.

+  // We do this just before seccomp-bpf is initialized.

[Mark Seaborn, 2014/05/15 16:21:25]

Maybe omit "just", so that this doesn't become wrong if someone adds code after
this?

[hidehiko, 2014/05/16 08:21:02]

Done.

+  CHECK(signal(SIGPIPE, SIG_IGN) != SIG_ERR);

[Mark Seaborn, 2014/05/15 16:21:25]

You could use PCHECK to print errno if this fails.

[hidehiko, 2014/05/16 08:21:02]

Done.

+
   // Finish layer-1 sandbox initialization and initialize the layer-2 sandbox.
   CHECK(!nacl_sandbox->HasOpenDirectory());
   nacl_sandbox->InitializeLayerTwoSandbox(uses_nonsfi_mode);
   nacl_sandbox->SealLayerOneSandbox();
   nacl_sandbox->CheckSandboxingStateWithPolicy();
 
   base::GlobalDescriptors::GetInstance()->Set(kPrimaryIPCChannel,
                                               browser_fd.release());
 
   base::MessageLoopForIO main_message_loop;
@@ skipping 329 matching lines @@
   // Now handle requests from the Zygote.
   while (true) {
     bool request_handled = HandleZygoteRequest(
         kNaClZygoteDescriptor, system_info, nacl_sandbox.get());
     // Do not turn this into a CHECK() without thinking about robustness
     // against malicious IPC requests.
     DCHECK(request_handled);
   }
   NOTREACHED();
 }