text: /*=========================================================================*\
  * Unix domain socket stream sub module
  * LuaSocket toolkit
  \*=========================================================================*/
  #ifndef _WIN32
  #include "luasocket.h"
  
  #include "auxiliar.h"
  #include "socket.h"
  #include "options.h"
  #include "unixstream.h"
  
  #include <string.h>
  #include <sys/un.h>
  
  /*=========================================================================*\
  * Internal function prototypes
  \*=========================================================================*/
  static int global_create(lua_State *L);
  static int meth_connect(lua_State *L);
  static int meth_listen(lua_State *L);
  static int meth_bind(lua_State *L);
  static int meth_send(lua_State *L);
  static int meth_shutdown(lua_State *L);
  static int meth_receive(lua_State *L);
  static int meth_accept(lua_State *L);
  static int meth_close(lua_State *L);
  static int meth_setoption(lua_State *L);
  static int meth_settimeout(lua_State *L);
  static int meth_getfd(lua_State *L);
  static int meth_setfd(lua_State *L);
  static int meth_dirty(lua_State *L);
  static int meth_getstats(lua_State *L);
  static int meth_setstats(lua_State *L);
  static int meth_getsockname(lua_State *L);
  
  static const char *unixstream_tryconnect(p_unix un, const char *path);
  static const char *unixstream_trybind(p_unix un, const char *path);
  
  /* unixstream object methods */
  static luaL_Reg unixstream_methods[] = {
      {"__gc",        meth_close},
      {"__tostring",  auxiliar_tostring},
      {"accept",      meth_accept},
      {"bind",        meth_bind},
      {"close",       meth_close},
      {"connect",     meth_connect},
      {"dirty",       meth_dirty},
      {"getfd",       meth_getfd},
      {"getstats",    meth_getstats},
      {"setstats",    meth_setstats},
      {"listen",      meth_listen},
      {"receive",     meth_receive},
      {"send",        meth_send},
      {"setfd",       meth_setfd},
      {"setoption",   meth_setoption},
      {"setpeername", meth_connect},
      {"setsockname", meth_bind},
      {"getsockname", meth_getsockname},
      {"settimeout",  meth_settimeout},
      {"shutdown",    meth_shutdown},
      {NULL,          NULL}
  };
  
  /* socket option handlers */
  static t_opt optset[] = {
      {"keepalive",   opt_set_keepalive},
      {"reuseaddr",   opt_set_reuseaddr},
      {"linger",      opt_set_linger},
      {NULL,          NULL}
  };
  
  /* functions in library namespace */
  static luaL_Reg func[] = {
      {"stream", global_create},
      {NULL, NULL}
  };
  
  /*-------------------------------------------------------------------------*\
  * Initializes module
  \*-------------------------------------------------------------------------*/
  int unixstream_open(lua_State *L)
  {
      /* create classes */
      auxiliar_newclass(L, "unixstream{master}", unixstream_methods);
      auxiliar_newclass(L, "unixstream{client}", unixstream_methods);
      auxiliar_newclass(L, "unixstream{server}", unixstream_methods);
  
      /* create class groups */
      auxiliar_add2group(L, "unixstream{master}", "unixstream{any}");
      auxiliar_add2group(L, "unixstream{client}", "unixstream{any}");
      auxiliar_add2group(L, "unixstream{server}", "unixstream{any}");
  
      luaL_setfuncs(L, func, 0);
      return 0;
  }
  
  /*=========================================================================*\
  * Lua methods
  \*=========================================================================*/
  /*-------------------------------------------------------------------------*\
  * Just call buffered IO methods
  \*-------------------------------------------------------------------------*/
  static int meth_send(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkclass(L, "unixstream{client}", 1);
      return buffer_meth_send(L, &un->buf);
  }
  
  static int meth_receive(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkclass(L, "unixstream{client}", 1);
      return buffer_meth_receive(L, &un->buf);
  }
  
  static int meth_getstats(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkclass(L, "unixstream{client}", 1);
      return buffer_meth_getstats(L, &un->buf);
  }
  
  static int meth_setstats(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkclass(L, "unixstream{client}", 1);
      return buffer_meth_setstats(L, &un->buf);
  }
  
  /*-------------------------------------------------------------------------*\
  * Just call option handler
  \*-------------------------------------------------------------------------*/
  static int meth_setoption(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkgroup(L, "unixstream{any}", 1);
      return opt_meth_setoption(L, optset, &un->sock);
  }
  
  /*-------------------------------------------------------------------------*\
  * Select support methods
  \*-------------------------------------------------------------------------*/
  static int meth_getfd(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkgroup(L, "unixstream{any}", 1);
      lua_pushnumber(L, (int) un->sock);
      return 1;
  }
  
  /* this is very dangerous, but can be handy for those that are brave enough */
  static int meth_setfd(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkgroup(L, "unixstream{any}", 1);
      un->sock = (t_socket) luaL_checknumber(L, 2);
      return 0;
  }
  
  static int meth_dirty(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkgroup(L, "unixstream{any}", 1);
      lua_pushboolean(L, !buffer_isempty(&un->buf));
      return 1;
  }
  
  /*-------------------------------------------------------------------------*\
  * Waits for and returns a client object attempting connection to the
  * server object
  \*-------------------------------------------------------------------------*/
  static int meth_accept(lua_State *L) {
      p_unix server = (p_unix) auxiliar_checkclass(L, "unixstream{server}", 1);
      p_timeout tm = timeout_markstart(&server->tm);
      t_socket sock;
      int err = socket_accept(&server->sock, &sock, NULL, NULL, tm);
      /* if successful, push client socket */
      if (err == IO_DONE) {
          p_unix clnt = (p_unix) lua_newuserdata(L, sizeof(t_unix));
          auxiliar_setclass(L, "unixstream{client}", -1);
          /* initialize structure fields */
          socket_setnonblocking(&sock);
          clnt->sock = sock;
          io_init(&clnt->io, (p_send)socket_send, (p_recv)socket_recv,
                  (p_error) socket_ioerror, &clnt->sock);
          timeout_init(&clnt->tm, -1, -1);
          buffer_init(&clnt->buf, &clnt->io, &clnt->tm);
          return 1;
      } else {
          lua_pushnil(L);
          lua_pushstring(L, socket_strerror(err));
          return 2;
      }
  }
  
  /*-------------------------------------------------------------------------*\
  * Binds an object to an address
  \*-------------------------------------------------------------------------*/
  static const char *unixstream_trybind(p_unix un, const char *path) {
      struct sockaddr_un local;
      size_t len = strlen(path);
      int err;
      if (len >= sizeof(local.sun_path)) return "path too long";
      memset(&local, 0, sizeof(local));
      strcpy(local.sun_path, path);
      local.sun_family = AF_UNIX;
  #ifdef UNIX_HAS_SUN_LEN
      local.sun_len = sizeof(local.sun_family) + sizeof(local.sun_len)
          + len + 1;
      err = socket_bind(&un->sock, (SA *) &local, local.sun_len);
  
  #else
      err = socket_bind(&un->sock, (SA *) &local,
              sizeof(local.sun_family) + len);
  #endif
      if (err != IO_DONE) socket_destroy(&un->sock);
      return socket_strerror(err);
  }
  
  static int meth_bind(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkclass(L, "unixstream{master}", 1);
      const char *path =  luaL_checkstring(L, 2);
      const char *err = unixstream_trybind(un, path);
      if (err) {
          lua_pushnil(L);
          lua_pushstring(L, err);
          return 2;
      }
      lua_pushnumber(L, 1);
      return 1;
  }
  
  static int meth_getsockname(lua_State *L)
  {
      p_unix un = (p_unix) auxiliar_checkgroup(L, "unixstream{any}", 1);
      struct sockaddr_un peer = {0};
      socklen_t peer_len = sizeof(peer);
  
      if (getsockname(un->sock, (SA *) &peer, &peer_len) < 0) {
          lua_pushnil(L);
          lua_pushstring(L, socket_strerror(errno));
          return 2;
      }
  
      lua_pushstring(L, peer.sun_path);
      return 1;
  }
  
  /*-------------------------------------------------------------------------*\
  * Turns a master unixstream object into a client object.
  \*-------------------------------------------------------------------------*/
  static const char *unixstream_tryconnect(p_unix un, const char *path)
  {
      struct sockaddr_un remote;
      int err;
      size_t len = strlen(path);
      if (len >= sizeof(remote.sun_path)) return "path too long";
      memset(&remote, 0, sizeof(remote));
      strcpy(remote.sun_path, path);
      remote.sun_family = AF_UNIX;
      timeout_markstart(&un->tm);
  #ifdef UNIX_HAS_SUN_LEN
      remote.sun_len = sizeof(remote.sun_family) + sizeof(remote.sun_len)
          + len + 1;
      err = socket_connect(&un->sock, (SA *) &remote, remote.sun_len, &un->tm);
  #else
      err = socket_connect(&un->sock, (SA *) &remote,
              sizeof(remote.sun_family) + len, &un->tm);
  #endif
      if (err != IO_DONE) socket_destroy(&un->sock);
      return socket_strerror(err);
  }
  
  static int meth_connect(lua_State *L)
  {
      p_unix un = (p_unix) auxiliar_checkclass(L, "unixstream{master}", 1);
      const char *path =  luaL_checkstring(L, 2);
      const char *err = unixstream_tryconnect(un, path);
      if (err) {
          lua_pushnil(L);
          lua_pushstring(L, err);
          return 2;
      }
      /* turn master object into a client object */
      auxiliar_setclass(L, "unixstream{client}", 1);
      lua_pushnumber(L, 1);
      return 1;
  }
  
  /*-------------------------------------------------------------------------*\
  * Closes socket used by object
  \*-------------------------------------------------------------------------*/
  static int meth_close(lua_State *L)
  {
      p_unix un = (p_unix) auxiliar_checkgroup(L, "unixstream{any}", 1);
      socket_destroy(&un->sock);
      lua_pushnumber(L, 1);
      return 1;
  }
  
  /*-------------------------------------------------------------------------*\
  * Puts the sockt in listen mode
  \*-------------------------------------------------------------------------*/
  static int meth_listen(lua_State *L)
  {
      p_unix un = (p_unix) auxiliar_checkclass(L, "unixstream{master}", 1);
      int backlog = (int) luaL_optnumber(L, 2, 32);
      int err = socket_listen(&un->sock, backlog);
      if (err != IO_DONE) {
          lua_pushnil(L);
          lua_pushstring(L, socket_strerror(err));
          return 2;
      }
      /* turn master object into a server object */
      auxiliar_setclass(L, "unixstream{server}", 1);
      lua_pushnumber(L, 1);
      return 1;
  }
  
  /*-------------------------------------------------------------------------*\
  * Shuts the connection down partially
  \*-------------------------------------------------------------------------*/
  static int meth_shutdown(lua_State *L)
  {
      /* SHUT_RD,  SHUT_WR,  SHUT_RDWR  have  the value 0, 1, 2, so we can use method index directly */
      static const char* methods[] = { "receive", "send", "both", NULL };
      p_unix stream = (p_unix) auxiliar_checkclass(L, "unixstream{client}", 1);
      int how = luaL_checkoption(L, 2, "both", methods);
      socket_shutdown(&stream->sock, how);
      lua_pushnumber(L, 1);
      return 1;
  }
  
  /*-------------------------------------------------------------------------*\
  * Just call tm methods
  \*-------------------------------------------------------------------------*/
  static int meth_settimeout(lua_State *L) {
      p_unix un = (p_unix) auxiliar_checkgroup(L, "unixstream{any}", 1);
      return timeout_meth_settimeout(L, &un->tm);
  }
  
  /*=========================================================================*\
  * Library functions
  \*=========================================================================*/
  /*-------------------------------------------------------------------------*\
  * Creates a master unixstream object
  \*-------------------------------------------------------------------------*/
  static int global_create(lua_State *L) {
      t_socket sock;
      int err = socket_create(&sock, AF_UNIX, SOCK_STREAM, 0);
      /* try to allocate a system socket */
      if (err == IO_DONE) {
          /* allocate unixstream object */
          p_unix un = (p_unix) lua_newuserdata(L, sizeof(t_unix));
          /* set its type as master object */
          auxiliar_setclass(L, "unixstream{master}", -1);
          /* initialize remaining structure fields */
          socket_setnonblocking(&sock);
          un->sock = sock;
          io_init(&un->io, (p_send) socket_send, (p_recv) socket_recv,
                  (p_error) socket_ioerror, &un->sock);
          timeout_init(&un->tm, -1, -1);
          buffer_init(&un->buf, &un->io, &un->tm);
          return 1;
      } else {
          lua_pushnil(L);
          lua_pushstring(L, socket_strerror(err));
          return 2;
      }
  }
  
  #endif
  