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         if (errno == EAGAIN) {
  30                 lua_pushboolean(L, 0);
  31         } else {
  32                 lua_pushnil(L);
  33         }
  34     lua_pushinteger(L, errno);
  35     lua_pushstring(L, strerror(errno));
  36     return 3;
  37 }
  38
  39 /* pushes true, if operation succeeded, otherwise call nixio__perror */
  40 int nixio__pstatus(lua_State *L, int condition) {
  41         if (condition) {
  42                 lua_pushboolean(L, 1);
  43                 return 1;
  44         } else {
  45                 return nixio__perror(L);
  46         }
  47 }
  48
  49 /* checks whether the first argument is a socket and returns it */
  50 nixio_sock* nixio__checksock(lua_State *L) {
  51     nixio_sock *sock = (nixio_sock*)luaL_checkudata(L, 1, NIXIO_META);
  52     luaL_argcheck(L, sock->fd != -1, 1, "invalid socket object");
  53     return sock;
  54 }
  55
  56 FILE* nixio__checkfile(lua_State *L) {
  57         FILE **fpp = (FILE**)luaL_checkudata(L, 1, NIXIO_FILE_META);
  58         luaL_argcheck(L, *fpp, 1, "invalid file object");
  59         return *fpp;
  60 }
  61
  62 /* read fd from nixio_sock object */
  63 int nixio__checksockfd(lua_State *L) {
  64         return nixio__checksock(L)->fd;
  65 }
  66
  67 /* return any possible fd, otherwise error out */
  68 int nixio__checkfd(lua_State *L, int ud) {
  69         int fd = nixio__tofd(L, ud);
  70         return (fd != -1) ? fd : luaL_argerror(L, ud, "invalid file descriptor");
  71 }
  72
  73 /* return any possible fd */
  74 int nixio__tofd(lua_State *L, int ud) {
  75         void *udata = lua_touserdata(L, ud);
  76         int fd = -1;
  77         if (lua_getmetatable(L, ud)) {
  78                 luaL_getmetatable(L, NIXIO_META);
  79                 luaL_getmetatable(L, NIXIO_FILE_META);
  80                 luaL_getmetatable(L, LUA_FILEHANDLE);
  81                 if (lua_rawequal(L, -3, -4)) {
  82                         fd = ((nixio_sock*)udata)->fd;
  83                 } else if (lua_rawequal(L, -2, -4) || lua_rawequal(L, -1, -4)) {
  84                         fd = (*((FILE **)udata)) ? fileno(*((FILE **)udata)) : -1;
  85                 }
  86                 lua_pop(L, 4);
  87         }
  88         return fd;
  89 }
  90
  91 /* object table */
  92 static const luaL_reg R[] = {
  93         {NULL,                  NULL}
  94 };
  95
  96 /* entry point */
  97 LUALIB_API int luaopen_nixio(lua_State *L) {
  98         /* create metatable */
  99         luaL_newmetatable(L, NIXIO_META);
 100
 101         /* metatable.__index = metatable */
 102         lua_pushvalue(L, -1);
 103         lua_setfield(L, -2, "__index");
 104
 105         /* register module */
 106         luaL_register(L, "nixio", R);
 107
 108         /* register metatable as socket_meta */
 109         lua_pushvalue(L, -2);
 110         lua_setfield(L, -2, "socket_meta");
 111
 112         /* register methods */
 113         nixio_open_file(L);
 114         nixio_open_socket(L);
 115         nixio_open_sockopt(L);
 116         nixio_open_bind(L);
 117         nixio_open_address(L);
 118         nixio_open_poll(L);
 119         nixio_open_io(L);
 120         nixio_open_splice(L);
 121
 122         /* module version */
 123         lua_pushnumber(L, VERSION);
 124         lua_setfield(L, -2, "version");
 125
 126         /* some constants */
 127         lua_createtable(L, 0, 1);
 128
 129         NIXIO_PUSH_CONSTANT(EACCES);
 130         NIXIO_PUSH_CONSTANT(ENOSYS);
 131         NIXIO_PUSH_CONSTANT(EINVAL);
 132         NIXIO_PUSH_CONSTANT(EWOULDBLOCK);
 133         NIXIO_PUSH_CONSTANT(EAGAIN);
 134         NIXIO_PUSH_CONSTANT(ENOMEM);
 135
 136         lua_setfield(L, -2, "const");
 137
 138         /* remove meta table */
 139         lua_remove(L, -2);
 140
 141         return 1;
 142 }