tests,base: Added GTest for base/socket.cc

It should be noted that some features of this class have not been fully
tested due to interaction with system-calls.

Change-Id: I8315188327e022ac4c98aa9ce4bd38243266ab17
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23984
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/base/SConscript

@@ -70,6 +70,7 @@ Source('random.cc')
 if env['TARGET_ISA'] != 'null':
     Source('remote_gdb.cc')
 Source('socket.cc')
+GTest('socket.test', 'socket.test.cc', 'socket.cc')
 Source('statistics.cc')
 Source('str.cc')
 GTest('str.test', 'str.test.cc', 'str.cc')

src/base/socket.cc

@@ -1,4 +1,7 @@
 /*
+ * Copyright (c) 2020 The Regents of the University of California
+ * All rights reserved
+ *
  * Copyright (c) 2002-2005 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -26,6 +29,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Authors: Nathan Binkert
+ *          Bobby R. Bruce
  */
 
 #include "base/socket.hh"
@@ -49,6 +53,14 @@ bool ListenSocket::anyListening = false;
 
 bool ListenSocket::bindToLoopback = false;
 
+void
+ListenSocket::cleanup()
+{
+    listeningDisabled = false;
+    anyListening = false;
+    bindToLoopback = false;
+}
+
 void
 ListenSocket::disableAll()
 {

src/base/socket.hh

@@ -49,6 +49,12 @@ class ListenSocket
     bool listening;
     int fd;
 
+    /*
+     * cleanup resets the static variables back to their default values.
+     */
+    static void cleanup();
+
+
   public:
     ListenSocket();
     virtual ~ListenSocket();

src/base/socket.test.cc

@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2020 The Regents of the University of California
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Bobby R. Bruce
+ */
+
+#include <gtest/gtest.h>
+
+#include "base/socket.hh"
+
+#define TEST_PORT_1 7893
+#define TEST_PORT_2 7894
+
+/*
+ * Socket.test tests socket.cc. It should be noted that some features of
+ * socket.cc have not been fully tested due to interaction with system-calls.
+ */
+
+class MockListenSocket : public ListenSocket
+{
+  public:
+    /*
+     * This mock Listen Socket is used to ensure the static variables are reset
+     * back to their default values after deconstruction (i.e., after a test
+     * has completed).
+     */
+    ~MockListenSocket()
+    {
+        cleanup();
+    }
+};
+
+TEST(SocketTest, DefaultBehavior)
+{
+    /*
+     * Tests the default behavior where listenSocket is constructed, and is
+     * not listening to a port.
+     */
+    MockListenSocket listen_socket;
+    EXPECT_EQ(-1, listen_socket.getfd());
+    EXPECT_FALSE(listen_socket.islistening());
+    EXPECT_FALSE(listen_socket.allDisabled());
+}
+
+TEST(SocketTest, DisableAll)
+{
+    MockListenSocket listen_socket;
+    listen_socket.disableAll();
+    EXPECT_EQ(-1, listen_socket.getfd());
+    EXPECT_FALSE(listen_socket.islistening());
+    EXPECT_TRUE(listen_socket.allDisabled());
+}
+
+TEST(SocketTest, ListenToPort)
+{
+    MockListenSocket listen_socket;
+    EXPECT_TRUE(listen_socket.listen(TEST_PORT_1));
+    EXPECT_NE(-1, listen_socket.getfd());
+    EXPECT_TRUE(listen_socket.islistening());
+    EXPECT_FALSE(listen_socket.allDisabled());
+}
+
+TEST(SocketTest, ListenToPortReuseFalse)
+{
+    MockListenSocket listen_socket;
+    /*
+     * The ListenSocket object should have the same state regardless as to
+     * whether reuse is true or false (it is true by default).
+     */
+    EXPECT_TRUE(listen_socket.listen(TEST_PORT_1, false));
+    EXPECT_NE(-1, listen_socket.getfd());
+    EXPECT_TRUE(listen_socket.islistening());
+    EXPECT_FALSE(listen_socket.allDisabled());
+}
+
+TEST(SocketTest, RelistenWithSameInstanceSamePort)
+{
+    MockListenSocket listen_socket;
+    EXPECT_TRUE(listen_socket.listen(TEST_PORT_1));
+
+    /*
+     * You cannot listen to another port if you are already listening to one.
+     */
+    testing::internal::CaptureStderr();
+    EXPECT_ANY_THROW(listen_socket.listen(TEST_PORT_1));
+    std::string expected = "panic: Socket already listening!\n";
+    std::string actual = testing::internal::GetCapturedStderr().substr();
+
+    /*
+     * The GoogleExitLogger will output using the following:
+     * `std::cerr << loc.file << ":" << loc.line << ": " << s;`
+     * As we do not care about the file and line where the error originated
+     * (this may change, and it shouldn't break the test when this happens),
+     * we strip out the leading `<file>:<line>: ` (we simply remove everything
+     * prior to two characters after the second colon in the string).
+     */
+    actual = actual.substr(actual.find(":", actual.find(":") + 1) + 2);
+    EXPECT_EQ(expected, actual);
+}
+
+TEST(SocketTest, RelistenWithSameInstanceDifferentPort)
+{
+    MockListenSocket listen_socket;
+    EXPECT_TRUE(listen_socket.listen(TEST_PORT_1));
+
+    /*
+     * You cannot listen to another port if you are already listening to one.
+     */
+    testing::internal::CaptureStderr();
+    EXPECT_ANY_THROW(listen_socket.listen(TEST_PORT_2));
+
+    std::string expected = "panic: Socket already listening!\n";
+    std::string actual = testing::internal::GetCapturedStderr().substr();
+    actual = actual.substr(actual.find(":", actual.find(":") + 1) + 2);
+    EXPECT_EQ(expected, actual);
+}
+
+TEST(SocketTest, RelistenWithDifferentInstanceOnDifferentPort)
+{
+    MockListenSocket listen_socket;
+    EXPECT_TRUE(listen_socket.listen(TEST_PORT_1));
+
+    /*
+     * You can listen to another port with a different instance.
+     */
+    MockListenSocket listen_socket_2;
+    EXPECT_TRUE(listen_socket_2.listen(TEST_PORT_2));
+}
+
+TEST(SocketTest, RelistenWithDifferentInstanceOnSamePort)
+{
+    MockListenSocket listen_socket;
+    EXPECT_TRUE(listen_socket.listen(TEST_PORT_1));
+
+    /*
+     * You cannot listen to a port that's already being listened to.
+     */
+    MockListenSocket listen_socket_2;
+    EXPECT_FALSE(listen_socket_2.listen(TEST_PORT_1));
+}
+
+TEST(SocketTest, AcceptError)
+{
+    MockListenSocket listen_socket;
+    EXPECT_EQ(-1, listen_socket.accept());
+}