/*
 *  gcsd
 *
 *  gcsd the generic command sequencer daemon can be used to serialize
 *  commands sent over various paralell communication channels to a
 *  single command output. It can be seen as a multiplexer for any
 *  kind of communication between a single resource and various clients
 *  which want to submit commands to it or query information from it.
 *  gcsd is written in C and Lua. The goal is to provide an easy to
 *  understand high level API based on Lua which can be used to
 *  implement the business logic of the so formed multiplexer daemon.
 *
 *
 *  Copyright (C) 2009-2010 Markus Grueneis <gimpf@spreadspace.org>
 *                          Christian Pointner <equinox@spreadspace.org>
 *
 *  This file is part of gcsd.
 *
 *  gcsd is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  gcsd is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with gcsd. If not, see <http://www.gnu.org/licenses/>.
 */

#include <lua.h>
#include <lauxlib.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>

#include "l_rawio.h"


static int l_rawio_open(lua_State *L)
{
  const char* filename = luaL_checkstring(L,1);
  const char* mode_str = luaL_checkstring(L,2);
  int mode = 0;

  if(strstr(mode_str, "O_RDONLY")) mode |= O_RDONLY;
  if(strstr(mode_str, "O_WRONLY")) mode |= O_WRONLY;
  if(strstr(mode_str, "O_RDWR")) mode |= O_RDWR;
  int fd = open(filename, mode);

  lua_pushinteger(L, fd);
  return 1;
}

static int l_rawio_setnonblock(lua_State *L)
{
  int fd = luaL_checkint(L,1);
  int ret = fcntl(fd, F_SETFL, O_NONBLOCK);

  if(ret == -1) {
    lua_pushnil(L);
// FIXXXXXME: strerror is not threadsafe!!!
    lua_pushstring(L, strerror(errno));
    return 2;
  }
  lua_pushboolean(L, 1);
  return 1;
}

static int l_rawio_write(lua_State *L)
{
  int fd = luaL_checkint(L,1);
  size_t len = 0;
  const char* data = luaL_checklstring(L, 2, &len);

  int ret = write(fd, data, len);

  if(ret == -1) {
    lua_pushnil(L);
// FIXXXXXME: strerror is not threadsafe!!!
    lua_pushstring(L, strerror(errno));
    return 2;
  }
  lua_pushinteger(L, ret);
  return 1;
}

static int l_rawio_read(lua_State *L)
{
  int fd = luaL_checkint(L,1);
  size_t len = luaL_checkint(L,2);
  char* data = malloc(len);
  if(!data) {
    lua_pushnil(L);
    lua_pushstring(L, "bad alloc");
    return 2;
  }

  int ret = read(fd, data, len);

  if(ret == -1) {
    lua_pushnil(L);
// FIXXXXXME: strerror is not threadsafe!!!
    lua_pushstring(L, strerror(errno));
    free(data);
    return 2;
  }
  lua_pushlstring(L, data, ret);
  free(data);
  return 1;
}

static int l_rawio_close(lua_State *L)
{
  close(luaL_checkint(L,1));
  return 0;
}

static const struct luaL_Reg rawio_funcs [] = {
  { "open", l_rawio_open },
  { "setnonblock", l_rawio_setnonblock },
  { "write", l_rawio_write },
  { "read", l_rawio_read },
  { "close", l_rawio_close },
  { NULL, NULL }
};


LUALIB_API int luaopen_rawio(lua_State *L)
{
#if LUA_VERSION_NUM > 501
  lua_newtable(L);
  luaL_setfuncs(L, rawio_funcs, 0);
  lua_pushvalue(L, -1);
  lua_setglobal(L, LUA_RAWIOLIBNAME);
#else
  luaL_register(L, LUA_RAWIOLIBNAME, rawio_funcs);
#endif
  return 1;
}