Mojo: Prevent SIGPIPE (on sockets generated by PlatformChannelPair) on Mac.

R=darin@chromium.org
BUG=356195

Review URL: https://codereview.chromium.org/207453005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@259274 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 99 insertions, 0 deletions

diff --git a/mojo/embedder/platform_channel_pair_posix.cc b/mojo/embedder/platform_channel_pair_posix.cc
index d9e65ed..2d5e2ca 100644
--- a/mojo/embedder/platform_channel_pair_posix.cc
+++ b/mojo/embedder/platform_channel_pair_posix.cc
@@ -13,6 +13,7 @@
 #include "base/logging.h"
 #include "base/posix/global_descriptors.h"
 #include "base/strings/string_number_conversions.h"
+#include "build/build_config.h"
 #include "mojo/embedder/platform_handle.h"
 
 namespace mojo {
@@ -40,6 +41,17 @@ PlatformChannelPair::PlatformChannelPair() {
   PCHECK(fcntl(fds[0], F_SETFL, O_NONBLOCK) == 0);
   PCHECK(fcntl(fds[1], F_SETFL, O_NONBLOCK) == 0);
 
+#if defined(OS_MACOSX)
+  // This turns off |SIGPIPE| when writing to a closed socket (causing it to
+  // fail with |EPIPE| instead). On Linux, we have to use |send...()| with
+  // |MSG_NOSIGNAL| -- which is not supported on Mac -- instead.
+  int no_sigpipe = 1;
+  PCHECK(setsockopt(fds[0], SOL_SOCKET, SO_NOSIGPIPE, &no_sigpipe,
+                    sizeof(no_sigpipe)) == 0);
+  PCHECK(setsockopt(fds[1], SOL_SOCKET, SO_NOSIGPIPE, &no_sigpipe,
+                    sizeof(no_sigpipe)) == 0);
+#endif  // defined(OS_MACOSX)
+
   server_handle_.reset(PlatformHandle(fds[0]));
   DCHECK(server_handle_.is_valid());
   client_handle_.reset(PlatformHandle(fds[1]));
diff --git a/mojo/embedder/platform_channel_pair_posix_unittest.cc b/mojo/embedder/platform_channel_pair_posix_unittest.cc
new file mode 100644
index 0000000..23271da
--- /dev/null
+++ b/mojo/embedder/platform_channel_pair_posix_unittest.cc
@@ -0,0 +1,86 @@
+// Copyright 2014 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 "mojo/embedder/platform_channel_pair.h"
+
+#include <errno.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include "base/logging.h"
+#include "base/macros.h"
+#include "build/build_config.h"  // TODO(vtl): Remove this.
+#include "mojo/embedder/scoped_platform_handle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace embedder {
+namespace {
+
+class PlatformChannelPairPosixTest : public testing::Test {
+ public:
+  PlatformChannelPairPosixTest() {}
+  virtual ~PlatformChannelPairPosixTest() {}
+
+  virtual void SetUp() OVERRIDE {
+    // Make sure |SIGPIPE| isn't being ignored.
+    struct sigaction action = {};
+    action.sa_handler = SIG_DFL;
+    ASSERT_EQ(0, sigaction(SIGPIPE, &action, &old_action_));
+  }
+
+  virtual void TearDown() OVERRIDE {
+    // Restore the |SIGPIPE| handler.
+    ASSERT_EQ(0, sigaction(SIGPIPE, &old_action_, NULL));
+  }
+
+ private:
+  struct sigaction old_action_;
+
+  DISALLOW_COPY_AND_ASSIGN(PlatformChannelPairPosixTest);
+};
+
+// TODO(vtl): crbug.com/356195
+#if defined(OS_MACOSX)
+#define MAYBE_NoSigPipe NoSigPipe
+#else
+#define MAYBE_NoSigPipe DISABLED_NoSigPipe
+#endif
+TEST_F(PlatformChannelPairPosixTest, MAYBE_NoSigPipe) {
+  PlatformChannelPair channel_pair;
+
+  ScopedPlatformHandle server_handle = channel_pair.PassServerHandle().Pass();
+  ScopedPlatformHandle client_handle = channel_pair.PassClientHandle().Pass();
+
+  // Write to the client.
+  static const char kHello[] = "hello";
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(kHello)),
+            write(client_handle.get().fd, kHello, sizeof(kHello)));
+
+  // Close the client.
+  client_handle.reset();
+
+  // Read from the server; this should be okay.
+  char buffer[100] = {};
+  EXPECT_EQ(static_cast<ssize_t>(sizeof(kHello)),
+            read(server_handle.get().fd, buffer, sizeof(buffer)));
+  EXPECT_STREQ(kHello, buffer);
+
+  // Try reading again.
+  ssize_t result = read(server_handle.get().fd, buffer, sizeof(buffer));
+  // We should probably get zero (for "end of file"), but -1 would also be okay.
+  EXPECT_TRUE(result == 0 || result == -1);
+  if (result == -1)
+    PLOG(WARNING) << "read (expected 0 for EOF)";
+
+  // However, |write()| should fail outright.
+  result = write(server_handle.get().fd, kHello, sizeof(kHello));
+  EXPECT_EQ(-1, result);
+  if (errno != EPIPE)
+    PLOG(WARNING) << "write (expected EPIPE)";
+}
+
+}  // namespace
+}  // namespace embedder
+}  // namespace mojo
diff --git a/mojo/mojo.gyp b/mojo/mojo.gyp
index 37834b2..2d15e5a 100644
--- a/mojo/mojo.gyp
+++ b/mojo/mojo.gyp
@@ -180,6 +180,7 @@
       ],
       'sources': [
         'embedder/embedder_unittest.cc',
+        'embedder/platform_channel_pair_posix_unittest.cc',
         'system/core_impl_unittest.cc',
         'system/core_test_base.cc',
         'system/core_test_base.h',