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 "nixio.h"
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <errno.h>
  23
  24 #define VERSION 0.1
  25
  26
  27 /* pushes nil, error number and errstring on the stack */
  28 int nixio__perror(lua_State *L) {
  29     lua_pushnil(L);
  30     lua_pushinteger(L, errno);
  31     lua_pushstring(L, strerror(errno));
  32     return 3;
  33 }
  34
  35 /* pushes true, if operation succeeded, otherwise call nixio__perror */
  36 int nixio__pstatus(lua_State *L, int condition) {
  37         if (condition) {
  38                 lua_pushboolean(L, 1);
  39                 return 1;
  40         } else {
  41                 return nixio__perror(L);
  42         }
  43 }
  44
  45 /* checks whether the first argument is a socket and returns it */
  46 nixio_sock* nixio__checksock(lua_State *L) {
  47     nixio_sock *sock = (nixio_sock*)luaL_checkudata(L, 1, NIXIO_META);
  48     luaL_argcheck(L, sock->fd != -1, 1, "invalid socket object");
  49     return sock;
  50 }
  51
  52 FILE* nixio__checkfile(lua_State *L) {
  53         FILE **fpp = (FILE**)luaL_checkudata(L, 1, NIXIO_FILE_META);
  54         luaL_argcheck(L, *fpp, 1, "invalid file object");
  55         return *fpp;
  56 }
  57
  58 /* read fd from nixio_sock object */
  59 int nixio__checksockfd(lua_State *L) {
  60         return nixio__checksock(L)->fd;
  61 }
  62
  63 /* return any possible fd, otherwise error out */
  64 int nixio__checkfd(lua_State *L, int ud) {
  65         int fd = nixio__tofd(L, ud);
  66         return (fd != -1) ? fd : luaL_argerror(L, ud, "invalid file descriptor");
  67 }
  68
  69 /* return any possible fd */
  70 int nixio__tofd(lua_State *L, int ud) {
  71         void *udata = lua_touserdata(L, ud);
  72         int fd = -1;
  73         if (lua_getmetatable(L, ud)) {
  74                 luaL_getmetatable(L, NIXIO_META);
  75                 luaL_getmetatable(L, NIXIO_FILE_META);
  76                 luaL_getmetatable(L, LUA_FILEHANDLE);
  77                 if (lua_rawequal(L, -3, -4)) {
  78                         fd = ((nixio_sock*)udata)->fd;
  79                 } else if (lua_rawequal(L, -2, -4) || lua_rawequal(L, -1, -4)) {
  80                         fd = (*((FILE **)udata)) ? fileno(*((FILE **)udata)) : -1;
  81                 }
  82                 lua_pop(L, 4);
  83         }
  84         return fd;
  85 }
  86
  87 /* object table */
  88 static const luaL_reg R[] = {
  89         {NULL,                  NULL}
  90 };
  91
  92 /* entry point */
  93 LUALIB_API int luaopen_nixio(lua_State *L) {
  94         /* create metatable */
  95         luaL_newmetatable(L, NIXIO_META);
  96
  97         /* metatable.__index = metatable */
  98         lua_pushvalue(L, -1);
  99         lua_setfield(L, -2, "__index");
 100
 101         /* register module */
 102         luaL_register(L, "nixio", R);
 103
 104         /* register metatable as socket_meta */
 105         lua_pushvalue(L, -2);
 106         lua_setfield(L, -2, "socket_meta");
 107
 108         /* register methods */
 109         nixio_open_file(L);
 110         nixio_open_socket(L);
 111         nixio_open_sockopt(L);
 112         nixio_open_bind(L);
 113         nixio_open_address(L);
 114         nixio_open_poll(L);
 115         nixio_open_io(L);
 116         nixio_open_splice(L);
 117
 118         /* module version */
 119         lua_pushnumber(L, VERSION);
 120         lua_setfield(L, -2, "version");
 121
 122         /* remove meta table */
 123         lua_remove(L, -2);
 124
 125         return 1;
 126 }