Added support for net:getaddrinfo/1,2

Signed-off-by: Fred Dushin <[email protected]>

doc/src/programmers-guide.md

@@ -1860,3 +1860,39 @@ For example:
     end
 
 Close a UDP socket just as you would a TCP socket, as described above.
+
+### Miscellaneous Networking APIs
+
+You can retrieve information about hostnames and services using the `net:getaddrinfo/1` and  `net:getaddrinfo/2` functions.  The return value is a list of maps each of which contains address information about the host, including its family (`inet`), protocol (`tcp` or `udp`), type (`stream` or `dgram`), and the address, currently an IPv4 tuple.
+
+For example:
+
+    %% erlang
+    {ok, AddrInfos} = net:getaddrinfo("www.atomvm.net"),
+
+    lists:foreach(
+        fun(AddrInfo) ->
+            #{
+                family := Family,
+                protocol := Protocol,
+                type := Type,
+                address := Address
+            } = AddrInfo,
+
+            io:format("family: ~p prototcol: ~p type: ~p address: ~p", [Family, Protocol, Type, Address])
+
+        end,
+        AddrInfos
+    ),
+
+The `host` parameter can be a domain name (typically) or a dotted pair IPv4 address.
+
+If you want to narrow the information you get back to a specific service type, you can specify a service name or port number (as a string value) as the second parameter:
+
+    %% erlang
+    {ok, AddrInfos} = net:getaddrinfo("www.atomvm.net", "https"),
+    ...
+
+Service names are well-known identifiers on the internet, but they may vary from operating system to operating system.  See the `services(3)` man pages for more information.
+
+> Note.  Currently, the `net:getaddrinfo/1` function only supports reporting of IPv4 addresses.

libs/estdlib/src/CMakeLists.txt

@@ -41,6 +41,7 @@ set(ERLANG_MODULES
     lists
     maps
     math
+    net
     logger
     logger_std_h
     proplists

libs/estdlib/src/net.erl

@@ -0,0 +1,80 @@
+%
+% This file is part of AtomVM.
+%
+% Copyright 2023 Fred Dushin <[email protected]>
+%
+% Licensed under the Apache License, Version 2.0 (the "License");
+% you may not use this file except in compliance with the License.
+% You may obtain a copy of the License at
+%
+%    http://www.apache.org/licenses/LICENSE-2.0
+%
+% Unless required by applicable law or agreed to in writing, software
+% distributed under the License is distributed on an "AS IS" BASIS,
+% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+% See the License for the specific language governing permissions and
+% limitations under the License.
+%
+% SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
+%
+
+-module(net).
+
+-export([getaddrinfo/1, getaddrinfo/2]).
+
+%% nif call (so we can use guards at the API)
+-export([getaddrinfo_nif/2]).
+
+-type addrinfo() :: #{
+    family := socket:domain(),
+    socktype := socket:type(),
+    protocol := socket:protocol(),
+    %% NB. The erlang docs appear to be wrong about this
+    address := socket:sockaddr(),
+    addr := socket:sockaddr()
+}.
+
+-type service() :: string().
+
+-export_type([addrinfo/0, service/0]).
+
+%%-----------------------------------------------------------------------------
+%% @param   Host the host string for which to find address information
+%% @returns Address info for the specified host
+%% @equiv   getaddrinfo(Host, undefined)
+%% @doc     Retrieve address information for a given hostname.
+%% @end
+%%-----------------------------------------------------------------------------
+-spec getaddrinfo(Host :: string()) -> {ok, AddrInfo :: addrinfo()} | {error, Reason :: term()}.
+getaddrinfo(Host) when is_list(Host) ->
+    ?MODULE:getaddrinfo(Host, undefined).
+
+%%-----------------------------------------------------------------------------
+%% @param   Host the host string for which to find address information
+%% @param   Service the service string for which to find address information
+%% @returns Address info for the specified host and service
+%% @doc     Retrieve address information for a given hostname and service.
+%%
+%%          The `Host' parameter may be a fully qualified host name or a string
+%%          containing a valid dotted pair IP address.  (Currently, only IPv4 is
+%%          supported).
+%%
+%%          The `Service' parameter may be the name of a service (as defined via
+%%          `services(3)` or a string containing a decimal value of the same.
+%%
+%%          Note that the `Host' or `String' parameter may be `undefined', but
+%%          not both.
+%% @end
+%%-----------------------------------------------------------------------------
+-spec getaddrinfo(Host :: string() | undefined, Service :: service() | undefined) ->
+    {ok, AddrInfo :: addrinfo()} | {error, Reason :: term()}.
+getaddrinfo(Host, Service) when
+    (is_list(Host) orelse Host =:= undefined) andalso
+        (is_list(Service) orelse Service =:= undefined) andalso
+        not (Host =:= undefined andalso Service =:= undefined)
+->
+    ?MODULE:getaddrinfo_nif(Host, Service).
+
+%% @hidden
+getaddrinfo_nif(_Host, _Service) ->
+    erlang:nif_error(undefined).

src/libAtomVM/CMakeLists.txt

@@ -158,6 +158,7 @@ define_if_function_exists(libAtomVM open "fcntl.h" PUBLIC HAVE_OPEN)
 define_if_function_exists(libAtomVM close "unistd.h" PUBLIC HAVE_CLOSE)
 define_if_function_exists(libAtomVM mkfifo "sys/stat.h" PRIVATE HAVE_MKFIFO)
 define_if_function_exists(libAtomVM unlink "unistd.h" PRIVATE HAVE_UNLINK)
+define_if_function_exists(libAtomVM getservbyname "netdb.h" PRIVATE HAVE_SERVBYNAME)
 define_if_symbol_exists(libAtomVM O_CLOEXEC "fcntl.h" PRIVATE HAVE_O_CLOEXEC)
 define_if_symbol_exists(libAtomVM O_DIRECTORY "fcntl.h" PRIVATE HAVE_O_DIRECTORY)
 define_if_symbol_exists(libAtomVM O_DSYNC "fcntl.h" PRIVATE HAVE_O_DSYNC)

src/libAtomVM/interop.c

@@ -611,3 +611,25 @@ term interop_kv_get_value_default(term kv, AtomString key, term default_value, G
         return default_value;
     }
 }
+
+term interop_atom_term_select_atom(GlobalContext *global, const AtomStringIntPair *table, int value)
+{
+    int i;
+    for (i = 0; table[i].as_val != NULL; i++) {
+        if (value == table[i].i_val) {
+            int global_atom_index = globalcontext_insert_atom(global, table[i].as_val);
+            return term_from_atom_index(global_atom_index);
+        }
+    }
+    return term_invalid_term();
+}
+
+term interop_chars_to_list(const char *chars, size_t len, Heap *heap)
+{
+    term ret = term_nil();
+    for (int i = (int) len - 1; i >= 0; --i) {
+        term c_term = term_from_int(chars[i]);
+        ret = term_list_prepend(c_term, ret, heap);
+    }
+    return ret;
+}

src/libAtomVM/interop.h

@@ -74,6 +74,7 @@ term interop_proplist_get_value(term list, term key);
 term interop_proplist_get_value_default(term list, term key, term default_value);
 term interop_map_get_value(GlobalContext *glb, term map, term key);
 term interop_map_get_value_default(GlobalContext *glb, term map, term key, term default_value);
+term interop_chars_to_list(const char *chars, size_t len, Heap *heap);
 
 NO_DISCARD InteropFunctionResult interop_iolist_size(term t, size_t *size);
 NO_DISCARD InteropFunctionResult interop_write_iolist(term t, char *p);
@@ -147,4 +148,6 @@ static inline term interop_bytes_to_list(const void *bytes, int len, Heap *heap)
 }
 #endif
 
+term interop_atom_term_select_atom(GlobalContext *global, const AtomStringIntPair *table, int value);
+
 #endif