send(to), recv(from) in Luxio, and simple bindings to send and recv.

1 files changed, 115 insertions, 0 deletions

diff --git a/luxio.c b/luxio.c
index a796292..4490121 100644
--- a/luxio.c
+++ b/luxio.c
@@ -2595,6 +2595,116 @@ luxio_getaddrinfo(lua_State *L)
 	return 2;
 }
 
+/* Socket-related send and receive functions *********************************/
+
+static int
+luxio_send(lua_State *L)
+{
+    int fd = luaL_checkint(L, 1);
+    size_t count;
+    const char *buf = luaL_checklstring(L, 2, &count);
+    int flags = luaL_optint(L, 3, 0);
+    
+    lua_pushinteger(L, send(fd, buf, count, flags));
+    lua_pushinteger(L, errno);
+    
+    return 2;
+}
+
+static int
+luxio_sendto(lua_State *L)
+{
+    int fd = luaL_checkint(L, 1);
+    size_t count;
+    const char *buf = luaL_checklstring(L, 2, &count);
+    int flags = luaL_optint(L, 3, 0);
+    struct sockaddr *addr = luaL_checkudata(L, 4, LUXIO_SOCKADDR_METATABLE_NAME);
+    socklen_t l = luxio___sockaddr_len(L, addr);
+
+    lua_pushinteger(L, sendto(fd, buf, count, flags, addr, l));
+    lua_pushinteger(L, errno);
+    
+    return 2;
+}
+
+static int
+luxio_recv(lua_State *L)
+{
+    int fd = luaL_checkint(L, 1);
+    int count = luaL_checkint(L, 2);
+    int flags = luaL_optint(L, 3, 0);
+    ssize_t result;
+    char *buf = malloc(count);
+    
+    if (buf == NULL) {
+        lua_pushstring(L, "unable to allocate read buffer: memory exhausted");
+        lua_error(L);
+    }
+    
+    result = recv(fd, buf, count, flags);
+    
+    if (result == -1) {
+        lua_pushinteger(L, result);
+        lua_pushinteger(L, errno);
+    } else {
+        /* sadly there appears to be no way to avoid this copy.
+         * luaL_Buffer actually builds things on the C stack bytes at a time,
+         * and there is no way to pre-allocate a Lua type other than a
+         * userdatum.  Additionally, should Lua call its panic function because
+         * it can't allocate memory to copy this into, our buf will be leaked.
+         * We could perhaps fix this with a lot of faff, involving creating
+         * a userdatum for our buffer, and setting a __gc metamethod.
+         */
+        lua_pushlstring(L, buf, result);
+        lua_pushinteger(L, errno);
+    }
+
+    free(buf);
+
+    return 2;
+}
+
+static int
+luxio_recvfrom(lua_State *L)
+{
+    int fd = luaL_checkint(L, 1);
+    int count = luaL_checkint(L, 2);
+    int flags = luaL_optint(L, 3, 0);
+    struct sockaddr_storage addr;
+    socklen_t l = sizeof(addr);
+    ssize_t result;
+    char *buf = malloc(count);
+    
+    if (buf == NULL) {
+        lua_pushstring(L, "unable to allocate read buffer: memory exhausted");
+        lua_error(L);
+    }
+    
+    result = recvfrom(fd, buf, count, flags, (struct sockaddr *)&addr, &l);
+    
+    if (result == -1) {
+        free(buf);
+        lua_pushinteger(L, result);
+        lua_pushinteger(L, errno);
+        return 2;
+    }
+    
+    /* sadly there appears to be no way to avoid this copy.
+     * luaL_Buffer actually builds things on the C stack bytes at a time,
+     * and there is no way to pre-allocate a Lua type other than a
+     * userdatum.  Additionally, should Lua call its panic function because
+     * it can't allocate memory to copy this into, our buf will be leaked.
+     * We could perhaps fix this with a lot of faff, involving creating
+     * a userdatum for our buffer, and setting a __gc metamethod.
+     */
+    lua_pushlstring(L, buf, result);
+    free(buf);
+    lua_pushinteger(L, errno);
+    luxio__makesockaddr(L, (const struct sockaddr *)&addr, l);
+    
+    return 3;
+}
+
 /* Poll-binding functions ****************************************************/
 
 #define LUXIO_POLLFD_METATABLE "luxio.pollfdarray"
@@ -3224,6 +3334,11 @@ luxio_functions[] = {
 
 	{ "make_sockaddr", luxio_makesockaddr },
 
+    { "send", luxio_send },
+    { "sendto", luxio_sendto },
+    { "recv", luxio_recv },
+    { "recvfrom", luxio_recvfrom },
+    
 	{ "pollfds_new", luxio_pollfds_new },
 	{ "pollfds_resize", luxio_pollfds_resize },
 	{ "pollfds_setslot", luxio_pollfds_set_slot },