base,cpu,dev: Simplify ListenSocket::listen().

Remove the "reuse" parameter which default to true and was always
also explicitly set to true. Tidy up the code itself slightly, mostly
by using "panic_if" to remove some nesting.

Change-Id: Ie23971aabf2fe4252d27f1887468360722a72379
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/69159
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/base/remote_gdb.cc

@@ -417,7 +417,7 @@ BaseRemoteGDB::listen()
         return;
     }
 
-    while (!listener.listen(_port, true)) {
+    while (!listener.listen(_port)) {
         DPRINTF(GDBMisc, "Can't bind port %d\n", _port);
         _port++;
     }

src/base/socket.cc

@@ -185,24 +185,20 @@ ListenSocket::~ListenSocket()
 
 // Create a socket and configure it for listening
 bool
-ListenSocket::listen(int port, bool reuse)
+ListenSocket::listen(int port)
 {
-    if (listening)
-        panic("Socket already listening!");
+    panic_if(listening, "Socket already listening!");
 
     // only create socket if not already created by a previous call
     if (fd == -1) {
         fd = socketCloexec(PF_INET, SOCK_STREAM, 0);
-        if (fd < 0)
-            panic("Can't create socket:%s !", strerror(errno));
+        panic_if(fd < 0, "Can't create socket:%s !", strerror(errno));
     }
 
-    if (reuse) {
-        int i = 1;
-        if (::setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&i,
-                         sizeof(i)) < 0)
-            panic("ListenSocket(listen): setsockopt() SO_REUSEADDR failed!");
-    }
+    int i = 1;
+    int ret = ::setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
+    panic_if(ret < 0,
+            "ListenSocket(listen): setsockopt() SO_REUSEADDR failed!");
 
     struct sockaddr_in sockaddr;
     sockaddr.sin_family = PF_INET;
@@ -211,16 +207,16 @@ ListenSocket::listen(int port, bool reuse)
     sockaddr.sin_port = htons(port);
     // finally clear sin_zero
     std::memset(&sockaddr.sin_zero, 0, sizeof(sockaddr.sin_zero));
-    int ret = ::bind(fd, (struct sockaddr *)&sockaddr, sizeof (sockaddr));
+    ret = ::bind(fd, (struct sockaddr *)&sockaddr, sizeof (sockaddr));
     if (ret != 0) {
-        if (ret == -1 && errno != EADDRINUSE)
-            panic("ListenSocket(listen): bind() failed!");
+        panic_if(ret == -1 && errno != EADDRINUSE,
+                "ListenSocket(listen): bind() failed!");
         return false;
     }
 
     if (::listen(fd, 1) == -1) {
-        if (errno != EADDRINUSE)
-            panic("ListenSocket(listen): listen() failed!");
+        panic_if(errno != EADDRINUSE,
+                "ListenSocket(listen): listen() failed!");
         // User may decide to retry with a different port later; however, the
         // socket is already bound to a port and the next bind will surely
         // fail. We'll close the socket and reset fd to -1 so our user can

src/base/socket.hh

@@ -106,7 +106,7 @@ class ListenSocket
 
     virtual int accept();
 
-    virtual bool listen(int port, bool reuse = true);
+    virtual bool listen(int port);
 
     int getfd() const { return fd; }
     bool islistening() const { return listening; }

src/base/socket.test.cc

@@ -162,19 +162,6 @@ TEST(SocketTest, ListenToPort)
     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(TestPort1, false));
-    EXPECT_NE(-1, listen_socket.getfd());
-    EXPECT_TRUE(listen_socket.islistening());
-    EXPECT_FALSE(listen_socket.allDisabled());
-}
-
 TEST(SocketTest, RelistenWithSameInstanceSamePort)
 {
     MockListenSocket listen_socket;
@@ -185,7 +172,9 @@ TEST(SocketTest, RelistenWithSameInstanceSamePort)
      */
     gtestLogOutput.str("");
     EXPECT_ANY_THROW(listen_socket.listen(TestPort1));
-    std::string expected = "panic: Socket already listening!\n";
+    std::string expected =
+        "panic: panic condition listening occurred: "
+        "Socket already listening!\n";
     std::string actual = gtestLogOutput.str();
     EXPECT_EQ(expected, actual);
 }
@@ -201,7 +190,9 @@ TEST(SocketTest, RelistenWithSameInstanceDifferentPort)
     gtestLogOutput.str("");
     EXPECT_ANY_THROW(listen_socket.listen(TestPort2));
 
-    std::string expected = "panic: Socket already listening!\n";
+    std::string expected =
+        "panic: panic condition listening occurred: "
+        "Socket already listening!\n";
     std::string actual = gtestLogOutput.str();
     EXPECT_EQ(expected, actual);
 }

src/base/vnc/vncserver.cc

@@ -164,7 +164,7 @@ VncServer::listen(int port)
         return;
     }
 
-    while (!listener.listen(port, true)) {
+    while (!listener.listen(port)) {
         DPRINTF(VNC,
                 "can't bind address vnc server port %d in use PID %d\n",
                 port, getpid());

src/cpu/nativetrace.cc

@@ -45,8 +45,7 @@ NativeTrace::NativeTrace(const Params &p)
         fatal("All listeners are disabled!");
 
     int port = 8000;
-    while (!native_listener.listen(port, true))
-    {
+    while (!native_listener.listen(port)) {
         DPRINTF(GDBMisc, "Can't bind port %d\n", port);
         port++;
     }

src/dev/net/ethertap.cc

@@ -259,7 +259,7 @@ class TapListener
 void
 TapListener::listen()
 {
-    while (!listener.listen(port, true)) {
+    while (!listener.listen(port)) {
         DPRINTF(Ethernet, "TapListener(listen): Can't bind port %d\n", port);
         port++;
     }

src/dev/serial/terminal.cc

@@ -175,7 +175,7 @@ Terminal::listen(int port)
         return;
     }
 
-    while (!listener.listen(port, true)) {
+    while (!listener.listen(port)) {
         DPRINTF(Terminal,
                 ": can't bind address terminal port %d inuse PID %d\n",
                 port, getpid());