libs/nixio/src/nixio.c

   1 /*
   2  * nixio - Linux I/O library for lua
   3  *
   4  *   Copyright (C) 2009 Steven Barth <steven@midlink.org>
   5  *
   6  *  Licensed under the Apache License, Version 2.0 (the "License");
   7  *  you may not use this file except in compliance with the License.
   8  *  You may obtain a copy of the License at
   9  *
  10  *      http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  *  Unless required by applicable law or agreed to in writing, software
  13  *  distributed under the License is distributed on an "AS IS" BASIS,
  14  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  *  See the License for the specific language governing permissions and
  16  *  limitations under the License.
  17  */
  18
  19 #include <lua.h>
  20 #include <lualib.h>
  21 #include <lauxlib.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include "nixio.h"
  26
  27 #define VERSION 0.1
  28
  29
  30 /* pushes nil, error number and errstring on the stack */
  31 int nixio__perror(lua_State *L) {
  32     lua_pushnil(L);
  33     lua_pushinteger(L, errno);
  34     lua_pushstring(L, strerror(errno));
  35     return 3;
  36 }
  37
  38 /* pushes true, if operation succeeded, otherwise call nixio__perror */
  39 int nixio__pstatus(lua_State *L, int condition) {
  40         if (condition) {
  41                 lua_pushboolean(L, 1);
  42                 return 1;
  43         } else {
  44                 return nixio__perror(L);
  45         }
  46 }
  47
  48 /* checks whether the first argument is a socket and returns it */
  49 nixio_sock* nixio__checksock(lua_State *L) {
  50     nixio_sock *sock = (nixio_sock*)luaL_checkudata(L, 1, NIXIO_META);
  51     luaL_argcheck(L, sock->fd != -1, 1, "invalid socket object");
  52     return sock;
  53 }
  54
  55 /* read fd from nixio_sock object */
  56 int nixio__checksockfd(lua_State *L) {
  57         return nixio__checksock(L)->fd;
  58 }
  59
  60 /* return any possible fd, otherwise error out */
  61 int nixio__checkfd(lua_State *L, int ud) {
  62         int fd = nixio__tofd(L, ud);
  63         return (fd != -1) ? fd : luaL_argerror(L, ud, "invalid file descriptor");
  64 }
  65
  66 /* return any possible fd */
  67 int nixio__tofd(lua_State *L, int ud) {
  68         void *udata = lua_touserdata(L, ud);
  69         int fd = -1;
  70         if (udata && lua_getmetatable(L, ud)) {
  71                 luaL_getmetatable(L, NIXIO_META);
  72                 luaL_getmetatable(L, LUA_FILEHANDLE);
  73                 if (lua_rawequal(L, -2, -3)) {
  74                         fd = ((nixio_sock*)udata)->fd;
  75                 } else if (lua_rawequal(L, -1, -3)) {
  76                         fd = fileno(*((FILE **)udata));
  77                 }
  78                 lua_pop(L, 3);
  79         }
  80         return fd;
  81 }
  82
  83 /* object table */
  84 static const luaL_reg R[] = {
  85         {NULL,                  NULL}
  86 };
  87
  88 /* entry point */
  89 LUALIB_API int luaopen_nixio(lua_State *L) {
  90         /* create metatable */
  91         luaL_newmetatable(L, NIXIO_META);
  92
  93         /* method table */
  94         lua_newtable(L);
  95         lua_pushvalue(L, -1);
  96
  97         /* metatable.__index = M */
  98         lua_setfield(L, -3, "__index");
  99         lua_remove(L, -2);
 100
 101         /* register module */
 102         luaL_register(L, "nixio", R);
 103
 104         /* register methods */
 105         nixio_open_socket(L);
 106         nixio_open_sockopt(L);
 107         nixio_open_bind(L);
 108         nixio_open_address(L);
 109         nixio_open_poll(L);
 110         nixio_open_io(L);
 111
 112         /* module version */
 113         lua_pushnumber(L, VERSION);
 114         lua_setfield(L, -2, "version");
 115
 116         /* remove meta table */
 117         lua_remove(L, -2);
 118
 119         return 1;
 120 }