Add socket:getopt/2

Also fix error tuple of `socket:setopt/3` to be `{error, closed}` following
OTP.

Signed-off-by: Paul Guyot <pguyot@kallisys.net>

Author: pguyot

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Partial support for `erlang:fun_info/2`
 - Added support for `registered_name` in `erlang:process_info/2` and `Process.info/2`
 - Added `net:gethostname/0` on platforms with gethostname(3).
+- Added `socket:getopt/2`
 
 ### Fixed
 - ESP32: improved sntp sync speed from a cold boot.

libs/estdlib/src/socket.erl

@@ -38,6 +38,7 @@
     send/2,
     sendto/3,
     setopt/3,
+    getopt/2,
     connect/2,
     shutdown/2
 ]).
@@ -66,7 +67,9 @@
 -type in_addr() :: {0..255, 0..255, 0..255, 0..255}.
 -type port_number() :: 0..65535.
 
--type socket_option() :: {socket, reuseaddr} | {socket, linger}.
+-type socket_option() ::
+    {socket, reuseaddr | linger | type}
+    | {otp, recvbuf}.
 
 -export_type([
     socket/0,
@@ -443,11 +446,32 @@ sendto(Socket, Data, Dest) when is_binary(Data) ->
 sendto(Socket, Data, Dest) ->
     ?MODULE:nif_sendto(Socket, erlang:iolist_to_binary(Data), Dest).
 
+%%-----------------------------------------------------------------------------
+%% @param   Socket the socket
+%% @param   SocketOption the option
+%% @returns `{ok, Value}' if successful; `{error, Reason}', otherwise.
+%% @doc     Get a socket option.
+%%
+%%          Currently, the following options are supported:
+%%          <table>
+%%              <tr><td>`{socket, type}'</td><td>`type()'</td></tr>
+%%          </table>
+%%
+%% Example:
+%%
+%%      `{ok, stream} = socket:getopt(ListeningSocket, {socket, type})'
+%% @end
+%%-----------------------------------------------------------------------------
+-spec getopt(Socket :: socket(), SocketOption :: socket_option()) ->
+    {ok, Value :: term()} | {error, Reason :: term()}.
+getopt(_Socket, _SocketOption) ->
+    erlang:nif_error(undefined).
+
 %%-----------------------------------------------------------------------------
 %% @param   Socket the socket
 %% @param   SocketOption the option
 %% @param   Value the option value
-%% @returns `{ok, Address}' if successful; `{error, Reason}', otherwise.
+%% @returns `ok' if successful; `{error, Reason}', otherwise.
 %% @doc     Set a socket option.
 %%
 %%          Set an option on a socket.
@@ -456,6 +480,7 @@ sendto(Socket, Data, Dest) ->
 %%          <table>
 %%              <tr><td>`{socket, reuseaddr}'</td><td>`boolean()'</td></tr>
 %%              <tr><td>`{socket, linger}'</td><td>`#{onoff => boolean(), linger => non_neg_integer()}'</td></tr>
+%%              <tr><td>`{otp, recvbuf}'</td><td>`non_neg_integer()'</td></tr>
 %%          </table>
 %%
 %% Example:
@@ -465,7 +490,7 @@ sendto(Socket, Data, Dest) ->
 %% @end
 %%-----------------------------------------------------------------------------
 -spec setopt(Socket :: socket(), SocketOption :: socket_option(), Value :: term()) ->
-    ok | {error, Reason :: term()}.
+    ok | {error, any()}.
 setopt(_Socket, _SocketOption, _Value) ->
     erlang:nif_error(undefined).
 

src/libAtomVM/inet.c

@@ -44,6 +44,11 @@ enum inet_type inet_atom_to_type(term type, GlobalContext *global)
     return interop_atom_term_select_int(inet_type_table, type, global);
 }
 
+term inet_type_to_atom(enum inet_type type, GlobalContext *global)
+{
+    return interop_atom_term_select_atom(inet_type_table, (int) type, global);
+}
+
 static const AtomStringIntPair inet_protocol_table[] = {
     { ATOM_STR("\x2", "ip"), InetIpProtocol },
     { ATOM_STR("\x3", "tcp"), InetTcpProtocol },

src/libAtomVM/inet.h

@@ -59,6 +59,14 @@ enum inet_type
  */
 enum inet_type inet_atom_to_type(term type, GlobalContext *global);
 
+/**
+ * @brief Convert an inet type to an atom
+ * @param type the inet type
+ * @param global the global context
+ * @returns an atom representing the inet type
+ */
+term inet_type_to_atom(enum inet_type type, GlobalContext *global);
+
 enum inet_protocol
 {
     InetInvalidProtocol = 0,

src/libAtomVM/otp_socket.c

@@ -190,6 +190,7 @@ static const char *const onoff_atom = ATOM_STR("\x5", "onoff");
 static const char *const port_atom = ATOM_STR("\x4", "port");
 static const char *const rcvbuf_atom = ATOM_STR("\x6", "rcvbuf");
 static const char *const reuseaddr_atom = ATOM_STR("\x9", "reuseaddr");
+static const char *const type_atom = ATOM_STR("\x4", "type");
 
 #define CLOSED_FD 0
 
@@ -1064,6 +1065,95 @@ static term nif_socket_select_stop(Context *ctx, int argc, term argv[])
     return OK_ATOM;
 }
 
+//
+// getopt
+//
+
+static term nif_socket_getopt(Context *ctx, int argc, term argv[])
+{
+    TRACE("nif_socket_getopt\n");
+    UNUSED(argc);
+
+    VALIDATE_VALUE(argv[0], term_is_otp_socket);
+
+    GlobalContext *global = ctx->global;
+
+    struct SocketResource *rsrc_obj;
+    if (UNLIKELY(!term_to_otp_socket(argv[0], &rsrc_obj, ctx))) {
+        RAISE_ERROR(BADARG_ATOM);
+    }
+
+    SMP_RWLOCK_RDLOCK(rsrc_obj->socket_lock);
+
+#if OTP_SOCKET_BSD
+    if (rsrc_obj->fd == 0) {
+#elif OTP_SOCKET_LWIP
+    if (rsrc_obj->socket_state == SocketStateClosed) {
+#endif
+        SMP_RWLOCK_UNLOCK(rsrc_obj->socket_lock);
+        return make_error_tuple(CLOSED_ATOM, ctx);
+    }
+    term level_tuple = argv[1];
+
+    term level = term_get_tuple_element(level_tuple, 0);
+    int level_val = interop_atom_term_select_int(otp_socket_setopt_level_table, level, global);
+    switch (level_val) {
+        case OtpSocketSetoptLevelSocket: {
+            term opt = term_get_tuple_element(level_tuple, 1);
+            if (globalcontext_is_term_equal_to_atom_string(global, opt, type_atom)) {
+                enum inet_type type;
+#if OTP_SOCKET_BSD
+                int option_value;
+                socklen_t option_len = sizeof(option_value);
+                int res = getsockopt(rsrc_obj->fd, SOL_SOCKET, SO_TYPE, &option_value, &option_len);
+                if (UNLIKELY(res != 0)) {
+                    SMP_RWLOCK_UNLOCK(rsrc_obj->socket_lock);
+                    return make_errno_tuple(ctx);
+                } else {
+                    switch (option_value) {
+                        case SOCK_STREAM:
+                            type = InetStreamType;
+                            break;
+                        case SOCK_DGRAM:
+                            type = InetDgramType;
+                            break;
+                        default:
+                            SMP_RWLOCK_UNLOCK(rsrc_obj->socket_lock);
+                            RAISE_ERROR(BADARG_ATOM);
+                    }
+                }
+#elif OTP_SOCKET_LWIP
+                LWIP_BEGIN();
+                if (rsrc_obj->socket_state & SocketStateTCP) {
+                    type = InetStreamType;
+                } else {
+                    type = InetDgramType;
+                }
+                LWIP_END();
+#endif
+                if (UNLIKELY(memory_ensure_free_with_roots(ctx, TUPLE_SIZE(2), 1, argv, MEMORY_CAN_SHRINK) != MEMORY_GC_OK)) {
+                    AVM_LOGW(TAG, "Failed to allocate memory: %s:%i.", __FILE__, __LINE__);
+                    SMP_RWLOCK_UNLOCK(rsrc_obj->socket_lock);
+                    RAISE_ERROR(OUT_OF_MEMORY_ATOM);
+                }
+                term result = term_alloc_tuple(2, &ctx->heap);
+                term_put_tuple_element(result, 0, OK_ATOM);
+                term_put_tuple_element(result, 1, inet_type_to_atom(type, global));
+                SMP_RWLOCK_UNLOCK(rsrc_obj->socket_lock);
+                return result;
+            } else {
+                SMP_RWLOCK_UNLOCK(rsrc_obj->socket_lock);
+                RAISE_ERROR(BADARG_ATOM);
+            }
+        }
+        default: {
+            AVM_LOGE(TAG, "socket:getopt: Unsupported level");
+            SMP_RWLOCK_UNLOCK(rsrc_obj->socket_lock);
+            RAISE_ERROR(BADARG_ATOM);
+        }
+    }
+}
+
 //
 // setopt
 //
@@ -1090,7 +1180,7 @@ static term nif_socket_setopt(Context *ctx, int argc, term argv[])
     if (rsrc_obj->socket_state == SocketStateClosed) {
 #endif
         SMP_RWLOCK_UNLOCK(rsrc_obj->socket_lock);
-        return make_error_tuple(posix_errno_to_term(EBADF, global), ctx);
+        return make_error_tuple(CLOSED_ATOM, ctx);
     }
     term level_tuple = argv[1];
     term value = argv[2];
@@ -2573,6 +2663,10 @@ static const struct Nif socket_select_stop_nif = {
     .base.type = NIFFunctionType,
     .nif_ptr = nif_socket_select_stop
 };
+static const struct Nif socket_getopt_nif = {
+    .base.type = NIFFunctionType,
+    .nif_ptr = nif_socket_getopt
+};
 static const struct Nif socket_setopt_nif = {
     .base.type = NIFFunctionType,
     .nif_ptr = nif_socket_setopt
@@ -2643,6 +2737,10 @@ const struct Nif *otp_socket_nif_get_nif(const char *nifname)
             TRACE("Resolved platform nif %s ...\n", nifname);
             return &socket_select_stop_nif;
         }
+        if (strcmp("getopt/2", rest) == 0) {
+            TRACE("Resolved platform nif %s ...\n", nifname);
+            return &socket_getopt_nif;
+        }
         if (strcmp("setopt/3", rest) == 0) {
             TRACE("Resolved platform nif %s ...\n", nifname);
             return &socket_setopt_nif;

tests/libs/estdlib/test_tcp_socket.erl

@@ -28,6 +28,7 @@ test() ->
     ok = test_close_by_another_process(),
     ok = test_buf_size(),
     ok = test_override_buf_size(),
+    ok = test_setopt_getopt(),
     case get_otp_version() of
         atomvm ->
             ok = test_abandon_select();
@@ -345,6 +346,15 @@ send_receive_loop(Socket, I) ->
             Error
     end.
 
+test_setopt_getopt() ->
+    {ok, Socket} = socket:open(inet, stream, tcp),
+    {ok, stream} = socket:getopt(Socket, {socket, type}),
+    ok = socket:setopt(Socket, {socket, reuseaddr}, true),
+    ok = socket:close(Socket),
+    {error, closed} = socket:getopt(Socket, {socket, type}),
+    {error, closed} = socket:setopt(Socket, {socket, reuseaddr}, true),
+    ok.
+
 %%
 %% abandon_select test
 %%

tests/libs/estdlib/test_udp_socket.erl

@@ -24,6 +24,7 @@
 
 test() ->
     ok = test_echo_server(),
+    ok = test_setopt_getopt(),
     ok.
 
 test_echo_server() ->
@@ -100,3 +101,12 @@ loop(Socket, Port, I) ->
             io:format("Error on sendto: ~p~n", [Error]),
             Error
     end.
+
+test_setopt_getopt() ->
+    {ok, Socket} = socket:open(inet, dgram, udp),
+    {ok, dgram} = socket:getopt(Socket, {socket, type}),
+    ok = socket:setopt(Socket, {socket, reuseaddr}, true),
+    ok = socket:close(Socket),
+    {error, closed} = socket:getopt(Socket, {socket, type}),
+    {error, closed} = socket:setopt(Socket, {socket, reuseaddr}, true),
+    ok.