base,python: Add a param type for host sockets.

These can either be set to an integer, in which case it's interpreted
as a TCP port, or a string, in which case it's treated as a unix domain
socket. If the unix domain socket is prefixed with a "@", it will be
treated as an abstract socket.

When stored in the ini file, there is always a prefix added to make
parsing the string more systematic and less ambiguous. A port number is
prefixed with "#", an abstract socket with "@", and a socket file with
the prefix "P" for "path".

Change-Id: I1fc7a579074e849b3becd936238c62fb0d9a2087
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/69165
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/base/socket.cc

@@ -208,6 +208,32 @@ ListenSocket::accept()
     return sfd;
 }
 
+bool
+ListenSocketConfig::parseIni(const std::string &value,
+        ListenSocketConfig &retval)
+{
+    if (value.size() == 0) {
+        retval = listenSocketEmptyConfig();
+        return true;
+    } else if (value[0] == '@') {
+        retval = listenSocketUnixAbstractConfig(value.substr(1));
+        return true;
+    } else if (value[0] == 'P') {
+        std::filesystem::path p(value.substr(1));
+        retval = listenSocketUnixFileConfig(p.parent_path(), p.filename());
+        return true;
+    } else if (value[0] == '#') {
+        uint64_t port;
+        bool ret = to_number(value.substr(1), port);
+        if (!ret)
+            return false;
+        retval = listenSocketInetConfig(port);
+        return true;
+    } else {
+        panic("Can't interpret %s as a host socket.", value);
+    }
+}
+
 ListenSocketInet::ListenSocketInet(const std::string &_name, int port)
     : ListenSocket(_name), _port(port)
 {}

src/base/socket.hh

@@ -159,6 +159,8 @@ class ListenSocketConfig
 
     operator bool() const { return (bool)builder; }
 
+    static bool parseIni(const std::string &value, ListenSocketConfig &retval);
+
   private:
     Builder builder;
 };

src/python/m5/params.py

@@ -1085,6 +1085,65 @@ class Bool(ParamValue):
         code(f"{ret} to_bool({src}, {dest});")
 
 
+class HostSocket(ParamValue):
+    cxx_type = "ListenSocketConfig"
+
+    @classmethod
+    def cxx_predecls(cls, code):
+        code('#include "base/socket.hh"')
+
+    def __init__(self, value):
+        if isinstance(value, HostSocket):
+            self.value = value.value
+        else:
+            self.value = value
+
+    def getValue(self):
+        from _m5.socket import listenSocketEmptyConfig
+        from _m5.socket import listenSocketInetConfig
+        from _m5.socket import listenSocketUnixFileConfig
+        from _m5.socket import listenSocketUnixAbstractConfig
+
+        if isinstance(self.value, str):
+            if self.value[0] == "@":
+                return listenSocketUnixAbstractConfig(self.value[1:])
+            else:
+                d, f = os.path.split(self.value)
+                return listenSocketUnixFileConfig(d, f)
+        else:
+            if self.value == 0:
+                return listenSocketEmptyConfig()
+            else:
+                return listenSocketInetConfig(self.value)
+
+    def __call__(self, value):
+        self.__init__(value)
+        return value
+
+    def __str__(self):
+        if isinstance(self.value, str):
+            return self.value
+        else:
+            return "#" + str(self.value)
+
+    def ini_str(self):
+        if isinstance(self.value, str):
+            if self.value[0] == "@":
+                return self.value
+            else:
+                return "P" + self.value
+        else:
+            return "#" + str(self.value)
+
+    @classmethod
+    def cxx_ini_predecls(cls, code):
+        code('#include "base/socket.hh"')
+
+    @classmethod
+    def cxx_ini_parse(cls, code, src, dest, ret):
+        code(f"{ret} ListenSocketConfig::parseIni({src}, {dest});")
+
+
 def IncEthernetAddr(addr, val=1):
     bytes = [int(x, 16) for x in addr.split(":")]
     bytes[5] += val

src/python/pybind11/core.cc

@@ -223,6 +223,20 @@ init_loader(py::module_ &m_native)
     m.def("setInterpDir", &loader::setInterpDir);
 }
 
+static void
+init_socket(py::module_ &m_native)
+{
+    py::module_ m_socket = m_native.def_submodule("socket");
+    m_socket
+        .def("listenSocketEmptyConfig", &listenSocketEmptyConfig)
+        .def("listenSocketInetConfig", &listenSocketInetConfig)
+        .def("listenSocketUnixFileConfig", &listenSocketUnixFileConfig)
+        .def("listenSocketUnixAbstractConfig",
+                &listenSocketUnixAbstractConfig);
+
+    py::class_<ListenSocketConfig>(m_socket, "ListenSocketConfig");
+}
+
 void
 pybind_init_core(py::module_ &m_native)
 {
@@ -334,6 +348,7 @@ pybind_init_core(py::module_ &m_native)
     init_net(m_native);
     init_loader(m_native);
     init_pc(m_native);
+    init_socket(m_native);
 }
 
 } // namespace gem5