socat/xio-unix.c

/* source: xio-unix.c */
/* Copyright Gerhard Rieger 2001-2008 */
/* Published under the GNU General Public License V.2, see file COPYING */

/* this file contains the source for opening addresses of UNIX socket type */

#include "xiosysincludes.h"
#include "xioopen.h"

#include "xio-socket.h"
#include "xio-listen.h"
#include "xio-unix.h"
#include "xio-named.h"


#if WITH_UNIX

static int xioopen_unix_connect(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *fd, unsigned groups, int dummy1, int dummy2, int dummy3);
static int xioopen_unix_listen(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *fd, unsigned groups, int dummy1, int dummy2, int dummy3);
static int xioopen_unix_sendto(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int dummy2, int dummy3);
static int xioopen_unix_recvfrom(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xfd, unsigned groups, int dummy1, int dummy2, int dummy3);
static
int xioopen_unix_recv(int argc, const char *argv[], struct opt *opts,
		      int xioflags, xiofile_t *xfd, unsigned groups,
		      int pf, int socktype, int ipproto);
static
int xioopen_unix_client(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xfd, unsigned groups, int dummy1, int dummy2, int dummy3);

#if WITH_ABSTRACT_UNIXSOCKET
static int xioopen_abstract_connect(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *fd, unsigned groups, int dummy1, int dummy2, int dummy3);
static int xioopen_abstract_listen(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *fd, unsigned groups, int dummy1, int dummy2, int dummy3);
static int xioopen_abstract_sendto(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int dummy2, int dummy3);
static int xioopen_abstract_recvfrom(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xfd, unsigned groups, int dummy1, int dummy2, int dummy3);
static
int xioopen_abstract_recv(int argc, const char *argv[], struct opt *opts,
		      int xioflags, xiofile_t *xfd, unsigned groups,
		      int pf, int socktype, int ipproto);
static
int xioopen_abstract_client(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xfd, unsigned groups, int dummy1, int dummy2, int dummy3);
#endif /* WITH_ABSTRACT_UNIXSOCKET */

const struct addrdesc addr_unix_connect = { "unix-connect",   3, xioopen_unix_connect, GROUP_FD|GROUP_NAMED|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY, 0, SOCK_STREAM, 0 HELP(":<filename>") };
#if WITH_LISTEN
const struct addrdesc addr_unix_listen  = { "unix-listen", 3, xioopen_unix_listen, GROUP_FD|GROUP_NAMED|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_LISTEN|GROUP_CHILD|GROUP_RETRY, 0, SOCK_STREAM, 0 HELP(":<filename>") };
#endif /* WITH_LISTEN */
const struct addrdesc addr_unix_sendto  = { "unix-sendto",  3, xioopen_unix_sendto, GROUP_FD|GROUP_NAMED|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY, 0, SOCK_DGRAM, 0 HELP(":<filename>") };
const struct addrdesc addr_unix_recvfrom= { "unix-recvfrom", 3, xioopen_unix_recvfrom, GROUP_FD|GROUP_NAMED|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY|GROUP_CHILD, PF_UNIX, SOCK_DGRAM, 0 HELP(":<filename>") };
const struct addrdesc addr_unix_recv    = { "unix-recv",     1, xioopen_unix_recv,     GROUP_FD|GROUP_NAMED|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY,             PF_UNIX, SOCK_DGRAM, 0 HELP(":<filename>") };
const struct addrdesc addr_unix_client  = { "unix-client",   3, xioopen_unix_client,   GROUP_FD|GROUP_NAMED|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY,             PF_UNIX, 0,          0 HELP(":<filename>") };
#if WITH_ABSTRACT_UNIXSOCKET
const struct addrdesc xioaddr_abstract_connect = { "abstract-connect",  3, xioopen_abstract_connect,  GROUP_FD|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY, 0, SOCK_STREAM, 0 HELP(":<filename>") };
#if WITH_LISTEN
const struct addrdesc xioaddr_abstract_listen  = { "abstract-listen",   3, xioopen_abstract_listen,   GROUP_FD|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_LISTEN|GROUP_CHILD|GROUP_RETRY, 0, SOCK_STREAM, 0 HELP(":<filename>") };
#endif /* WITH_LISTEN */
const struct addrdesc xioaddr_abstract_sendto  = { "abstract-sendto",   3, xioopen_abstract_sendto,   GROUP_FD|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY, 0, SOCK_DGRAM, 0 HELP(":<filename>") };
const struct addrdesc xioaddr_abstract_recvfrom= { "abstract-recvfrom", 3, xioopen_abstract_recvfrom, GROUP_FD|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY|GROUP_CHILD, PF_UNIX, SOCK_DGRAM, 0 HELP(":<filename>") };
const struct addrdesc xioaddr_abstract_recv    = { "abstract-recv",     1, xioopen_abstract_recv,     GROUP_FD|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY,             PF_UNIX, SOCK_DGRAM, 0 HELP(":<filename>") };
const struct addrdesc xioaddr_abstract_client  = { "abstract-client",   3, xioopen_abstract_client,   GROUP_FD|GROUP_SOCKET|GROUP_SOCK_UNIX|GROUP_RETRY,             PF_UNIX, 0,          0 HELP(":<filename>") };
#endif /* WITH_ABSTRACT_UNIXSOCKET */

const struct optdesc opt_unix_tightsocklen = { "unix-tightsocklen",    "tightsocklen",  OPT_UNIX_TIGHTSOCKLEN,  GROUP_SOCK_UNIX, PH_INIT, TYPE_BOOL, OFUNC_SPEC, 0, 0 };


socklen_t
xiosetunix(struct sockaddr_un *saun,
	   const char *path,
	   bool abstract,
	   bool tight) {
   size_t pathlen;
   socklen_t len;

   if (!abstract) {
      if ((pathlen = strlen(path)) > sizeof(saun->sun_path)) {
	 Warn2("unix socket address "F_Zu" characters long, truncating to "F_Zu"",
	       pathlen, sizeof(saun->sun_path));
      }
      strncpy(saun->sun_path, path, sizeof(saun->sun_path));
      if (tight) {
	 len = sizeof(struct sockaddr_un)-sizeof(saun->sun_path)+
	    MIN(pathlen, sizeof(saun->sun_path));
#if HAVE_STRUCT_SOCKADDR_SALEN
	 saun->sun_len = len;
#endif
      } else {
	 len = sizeof(struct sockaddr_un);
      }
   } else {
      if ((pathlen = strlen(path)) >= sizeof(saun->sun_path)) {
	 Warn2("socket address "F_Zu" characters long, truncating to "F_Zu"",
	       pathlen+1, sizeof(saun->sun_path));
      }
      saun->sun_path[0] = '\0';	/* so it's abstract */
      strncpy(saun->sun_path+1, path, sizeof(saun->sun_path)-1);
      if (tight) {
	 len = sizeof(struct sockaddr_un)-sizeof(saun->sun_path)+
	    MIN(pathlen+1, sizeof(saun->sun_path));
#if HAVE_STRUCT_SOCKADDR_SALEN
	 saun->sun_len = len;
#endif
      } else {
	 len = sizeof(struct sockaddr_un);
      }
   }
   return len;
}

#if WITH_LISTEN
static int xioopen_unix_listen(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int socktype, int dummy3) {
   /* we expect the form: filename */
   const char *name;
   xiosingle_t *xfd = &xxfd->stream;
   struct sockaddr_un us;
   socklen_t uslen;
   bool tight = true;
   struct opt *opts0 = NULL;
   bool opt_unlink_early = false;
   bool opt_unlink_close = true;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   socket_un_init(&us);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   uslen = xiosetunix(&us, name, false, tight);

   retropt_bool(opts, OPT_UNLINK_EARLY, &opt_unlink_early);
   retropt_bool(opts, OPT_UNLINK_CLOSE, &opt_unlink_close);

   if (opt_unlink_close) {
      if ((xfd->unlink_close = strdup(name)) == NULL) {
	 Error1("strdup(\"%s\"): out of memory", name);
      }
      xfd->opt_unlink_close = true;
   }

   xfd->howtoend = END_SHUTDOWN;

   applyopts(-1, opts, PH_INIT);
   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
   applyopts(-1, opts, PH_EARLY);

   if (opt_unlink_early) {
      if (Unlink(name) < 0) {
	 if (errno == ENOENT) {
	    Warn2("unlink(\"%s\"): %s", name, strerror(errno));
	 } else {
	    Error2("unlink(\"%s\"): %s", name, strerror(errno));
	 }
      }
   }

   /* trying to set user-early, perm-early etc. here is useless because
      file system entry is available only past bind() call. */
   applyopts_named(name, opts, PH_EARLY);	/* umask! */

   retropt_int(opts, OPT_SO_TYPE, &socktype);

   opts0 = copyopts(opts, GROUP_ALL);

   if ((result =
	xioopen_listen(xfd, xioflags,
		       (struct sockaddr *)&us, uslen,
		     opts, opts0, PF_UNIX, socktype, 0))
       != 0)
      return result;
   return 0;
}
#endif /* WITH_LISTEN */


static int xioopen_unix_connect(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int socktype, int dummy3) {
   /* we expect the form: filename */
   const char *name;
   struct single *xfd = &xxfd->stream;
   struct sockaddr_un them, us;
   socklen_t themlen, uslen;
   bool tight = true;
   bool needbind = false;
   bool opt_unlink_close = false;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   socket_un_init(&us);
   socket_un_init(&them);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   themlen = xiosetunix(&them, name, false, tight);
   retropt_bool(opts, OPT_UNLINK_CLOSE, &opt_unlink_close);

   if (retropt_bind(opts, AF_UNIX, socktype, 0, (struct sockaddr *)&us, &uslen, 0, 0, 0)
       != STAT_NOACTION) {
      needbind = true;
   }

   if (opt_unlink_close) {
      if ((xfd->unlink_close = strdup(name)) == NULL) {
	 Error1("strdup(\"%s\"): out of memory", name);
      }
      xfd->opt_unlink_close = true;
   }

   applyopts(-1, opts, PH_INIT);
   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
   applyopts(-1, opts, PH_EARLY);

   if ((result =
	xioopen_connect(xfd,
			needbind?(struct sockaddr *)&us:NULL, uslen,
			(struct sockaddr *)&them, themlen,
			opts, PF_UNIX, socktype, 0, false)) != 0) {
      return result;
   }
   if ((result = _xio_openlate(xfd, opts)) < 0) {
      return result;
   }
   return 0;
}


static int xioopen_unix_sendto(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int socktype, int dummy3) {
   const char *name;
   xiosingle_t *xfd = &xxfd->stream;
   union sockaddr_union us;
   socklen_t uslen;
   bool tight = true;
   int pf = PF_UNIX;
   bool needbind = false;
   bool opt_unlink_close = false;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   uslen = socket_init(pf, &us);
   xfd->salen = socket_init(pf, &xfd->peersa);

   xfd->howtoend = END_SHUTDOWN;

   retropt_int(opts, OPT_SO_TYPE, &socktype);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   xfd->salen = xiosetunix(&xfd->peersa.un, name, false, tight);

   retropt_bool(opts, OPT_UNLINK_CLOSE, &opt_unlink_close);

   xfd->dtype = XIODATA_RECVFROM;

   if (retropt_bind(opts, pf, socktype, 0, &us.soa, &uslen, 0, 0, 0)
       != STAT_NOACTION) {
      needbind = true;
   }

   if (opt_unlink_close) {
      if ((xfd->unlink_close = strdup(name)) == NULL) {
	 Error1("strdup(\"%s\"): out of memory", name);
      }
      xfd->opt_unlink_close = true;
   }

   applyopts(-1, opts, PH_INIT);
   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;

   return
      _xioopen_dgram_sendto(needbind?&us:NULL, uslen,
			  opts, xioflags, xfd, groups, pf, socktype, 0);
}


static
int xioopen_unix_recvfrom(int argc, const char *argv[], struct opt *opts,
		     int xioflags, xiofile_t *xfd, unsigned groups,
		     int pf, int socktype, int dummy3) {
   const char *name;
   struct sockaddr_un us;
   socklen_t uslen;
   bool tight = true;
   bool needbind = true;
   bool opt_unlink_early = false;
   bool opt_unlink_close = true;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   socket_un_init(&us);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   uslen = xiosetunix(&us, name, false, tight);

   xfd->stream.howtoend = END_NONE;
   retropt_int(opts, OPT_SO_TYPE, &socktype);
   retropt_bind(opts, pf, socktype, 0, (struct sockaddr *)&us, &uslen, 1, 0, 0);
   retropt_bool(opts, OPT_UNLINK_EARLY, &opt_unlink_early);
   retropt_bool(opts, OPT_UNLINK_CLOSE, &opt_unlink_close);

   if (opt_unlink_close) {
      if ((xfd->stream.unlink_close = strdup(name)) == NULL) {
	 Error1("strdup(\"%s\"): out of memory", name);
      }
      xfd->stream.opt_unlink_close = true;
   }

   if (opt_unlink_early) {
      if (Unlink(name) < 0) {
	 if (errno == ENOENT) {
	    Warn2("unlink(\"%s\"): %s", name, strerror(errno));
	 } else {
	    Error2("unlink(\"%s\"): %s", name, strerror(errno));
	 }
      }
   }

   xfd->stream.para.socket.la.soa.sa_family = pf;

   xfd->stream.dtype = XIODATA_RECVFROM_ONE;
   return _xioopen_dgram_recvfrom(&xfd->stream, xioflags,
				needbind?(struct sockaddr *)&us:NULL, uslen,
				opts, pf, socktype, 0, E_ERROR);
}


static
int xioopen_unix_recv(int argc, const char *argv[], struct opt *opts,
		      int xioflags, xiofile_t *xfd, unsigned groups,
		      int pf, int socktype, int ipproto) {
   const char *name;
   union sockaddr_union us;
   socklen_t uslen;
   bool tight = true;
   bool opt_unlink_early = false;
   bool opt_unlink_close = true;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   retropt_int(opts, OPT_SO_TYPE, &socktype);

   socket_un_init(&us.un);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   uslen = xiosetunix(&us.un, name, false, tight);

#if 1	/*!!! why bind option? */
   retropt_bind(opts, pf, socktype, ipproto, &us.soa, &uslen, 1, 0, 0);
#endif

   retropt_bool(opts, OPT_UNLINK_EARLY, &opt_unlink_early);
   if (opt_unlink_early) {
      if (Unlink(name) < 0) {
	 if (errno == ENOENT) {
	    Warn2("unlink(\"%s\"): %s", name, strerror(errno));
	 } else {
	    Error2("unlink(\"%s\"): %s", name, strerror(errno));
	 }
      }
   }

   retropt_bool(opts, OPT_UNLINK_CLOSE, &opt_unlink_close);

   if (opt_unlink_close) {
      if ((xfd->stream.unlink_close = strdup(name)) == NULL) {
	 Error1("strdup(\"%s\"): out of memory", name);
      }
      xfd->stream.opt_unlink_close = true;
   }

   xfd->stream.para.socket.la.soa.sa_family = pf;

   xfd->stream.dtype = XIODATA_RECV;
   result = _xioopen_dgram_recv(&xfd->stream, xioflags, &us.soa, uslen,
				opts, pf, socktype, ipproto, E_ERROR);
   return result;
}


static int xioopen_unix_client(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int socktype, int dummy3) {
   const char *name;
   xiosingle_t *xfd = &xxfd->stream;
   bool tight = true;
   int pf = PF_UNIX;
   union sockaddr_union them, us;
   socklen_t themlen;
   socklen_t uslen;
   bool needbind = false;
   bool opt_unlink_close = false;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)", argv[0], argc-1);
   }

   xfd->howtoend = END_SHUTDOWN;
   retropt_int(opts, OPT_SO_TYPE, &socktype);

   uslen = socket_init(pf, &us);
   themlen = socket_init(pf, &them);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   themlen = xiosetunix(&them.un, name, false, tight);

   retropt_bool(opts, OPT_UNLINK_CLOSE, &opt_unlink_close);

   if (retropt_bind(opts, pf, socktype, 0, &us.soa, &uslen, 0, 0, 0)
       != STAT_NOACTION) {
      needbind = true;
   }

   if (opt_unlink_close) {
      if ((xfd->unlink_close = strdup(name)) == NULL) {
	 Error1("strdup(\"%s\"): out of memory", name);
      }
      xfd->opt_unlink_close = true;
   }

   /* xfd->dtype = DATA_STREAM; // is default */
   if ((result =
	xioopen_connect(xfd,
		      needbind?(struct sockaddr *)&us:NULL, uslen,
			(struct sockaddr *)&them, themlen,
		      opts, PF_UNIX, socktype?socktype:SOCK_STREAM, 0, false)) != 0) {
      if (errno == EPROTOTYPE) {
	 if (needbind) {
	    Unlink(us.un.sun_path);
	 }

	 applyopts(-1, opts, PH_INIT);
	 if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;

	 xfd->peersa = them;
	 xfd->salen = sizeof(struct sockaddr_un);
	 if ((result =
	      _xioopen_dgram_sendto(needbind?&us:NULL, uslen,
				    opts, xioflags, xfd, groups, pf,
				    socktype?socktype:SOCK_DGRAM, 0))
	     != 0) {
	    return result;
	 }
	 xfd->dtype = XIODATA_RECVFROM;
      }
   }
   if ((result = _xio_openlate(xfd, opts)) < 0) {
      return result;
   }
   return 0;
}


#if WITH_ABSTRACT_UNIXSOCKET
#if WITH_LISTEN
static int xioopen_abstract_listen(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int socktype, int dummy3) {
   /* we expect the form: filename */
   const char *name;
   xiosingle_t *xfd = &xxfd->stream;
   bool tight = true;
   struct sockaddr_un us;
   socklen_t uslen;
   struct opt *opts0 = NULL;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   socket_un_init(&us);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   uslen = xiosetunix(&us, name, true, tight);

   xfd->howtoend = END_SHUTDOWN;

   applyopts(-1, opts, PH_INIT);
   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
   applyopts(-1, opts, PH_EARLY);

   /* trying to set user-early, perm-early etc. here is useless because
      file system entry is available only past bind() call. */

   retropt_int(opts, OPT_SO_TYPE, &socktype);

   opts0 = copyopts(opts, GROUP_ALL);

   if ((result =
	xioopen_listen(xfd, xioflags,
		       (struct sockaddr *)&us, uslen,
		     opts, opts0, PF_UNIX, socktype, 0))
       != 0)
      return result;
   return 0;
}
#endif /* WITH_LISTEN */

static int xioopen_abstract_connect(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int socktype, int dummy3) {
   /* we expect the form: filename */
   const char *name;
   struct single *xfd = &xxfd->stream;
   bool tight = true;
   struct sockaddr_un them, us;
   socklen_t themlen, uslen;
   bool needbind = false;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   socket_un_init(&us);
   socket_un_init(&them);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   themlen = xiosetunix(&them, name, true, tight);

   if (retropt_bind(opts, AF_UNIX, socktype, 0, (struct sockaddr *)&us, &uslen, 0, 0, 0)
       != STAT_NOACTION) {
      needbind = true;
   }

   applyopts(-1, opts, PH_INIT);
   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
   applyopts(-1, opts, PH_EARLY);

   if ((result =
	xioopen_connect(xfd,
			needbind?(struct sockaddr *)&us:NULL, uslen,
			(struct sockaddr *)&them, themlen,
			opts, PF_UNIX, socktype, 0, false)) != 0) {
      return result;
   }
   if ((result = _xio_openlate(xfd, opts)) < 0) {
      return result;
   }
   return 0;
}


static int xioopen_abstract_sendto(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int socktype, int dummy3) {
   const char *name;
   xiosingle_t *xfd = &xxfd->stream;
   union sockaddr_union us;
   socklen_t uslen;
   bool tight = true;
   int pf = PF_UNIX;
   bool needbind = false;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   uslen = socket_init(pf, &us);
   xfd->salen = socket_init(pf, &xfd->peersa);

   xfd->howtoend = END_SHUTDOWN;

   retropt_int(opts, OPT_SO_TYPE, &socktype);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   xfd->salen = xiosetunix(&xfd->peersa.un, name, true, tight);

   xfd->dtype = XIODATA_RECVFROM;

   if (retropt_bind(opts, pf, socktype, 0, &us.soa, &uslen, 0, 0, 0)
       != STAT_NOACTION) {
      needbind = true;
   }

   applyopts(-1, opts, PH_INIT);
   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;

   return
      _xioopen_dgram_sendto(needbind?&us:NULL, uslen,
			  opts, xioflags, xfd, groups, pf, socktype, 0);
}


static
int xioopen_abstract_recvfrom(int argc, const char *argv[], struct opt *opts,
		     int xioflags, xiofile_t *xfd, unsigned groups,
		     int pf, int socktype, int dummy3) {
   const char *name;
   struct sockaddr_un us;
   socklen_t uslen;
   bool tight = true;
   bool needbind = true;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   socket_un_init(&us);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   uslen = xiosetunix(&us, name, true, tight);

   xfd->stream.howtoend = END_NONE;
   retropt_int(opts, OPT_SO_TYPE, &socktype);
   retropt_bind(opts, pf, socktype, 0, (struct sockaddr *)&us, &uslen, 1, 0, 0);

   xfd->stream.para.socket.la.soa.sa_family = pf;

   xfd->stream.dtype = XIODATA_RECVFROM_ONE;
   return _xioopen_dgram_recvfrom(&xfd->stream, xioflags,
				needbind?(struct sockaddr *)&us:NULL, uslen,
				opts, pf, socktype, 0, E_ERROR);
}


static
int xioopen_abstract_recv(int argc, const char *argv[], struct opt *opts,
		      int xioflags, xiofile_t *xfd, unsigned groups,
		      int pf, int socktype, int ipproto) {
   const char *name;
   union sockaddr_union us;
   socklen_t uslen;
   bool tight = true;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   retropt_int(opts, OPT_SO_TYPE, &socktype);

   socket_un_init(&us.un);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   uslen = xiosetunix(&us.un, name, true, tight);

#if 1	/*!!! why bind option? */
   retropt_bind(opts, pf, socktype, ipproto, &us.soa, &uslen, 1, 0, 0);
#endif

   xfd->stream.para.socket.la.soa.sa_family = pf;

   xfd->stream.dtype = XIODATA_RECV;
   result = _xioopen_dgram_recv(&xfd->stream, xioflags, &us.soa, uslen,
				opts, pf, socktype, ipproto, E_ERROR);
   return result;
}


static int xioopen_abstract_client(int argc, const char *argv[], struct opt *opts, int xioflags, xiofile_t *xxfd, unsigned groups, int dummy1, int socktype, int dummy3) {
   const char *name;
   xiosingle_t *xfd = &xxfd->stream;
   bool tight = true;
   int pf = PF_UNIX;
   union sockaddr_union them, us;
   socklen_t themlen;
   socklen_t uslen;
   bool needbind = false;
   int result;

   if (argc != 2) {
      Error2("%s: wrong number of parameters (%d instead of 1)", argv[0], argc-1);
   }

   xfd->howtoend = END_SHUTDOWN;
   retropt_int(opts, OPT_SO_TYPE, &socktype);

   uslen = socket_init(pf, &us);
   themlen = socket_init(pf, &them);

   retropt_bool(opts, OPT_UNIX_TIGHTSOCKLEN, &tight);
   name = argv[1];
   themlen = xiosetunix(&them.un, name, true, tight);

   if (retropt_bind(opts, pf, socktype, 0, &us.soa, &uslen, 0, 0, 0)
       != STAT_NOACTION) {
      needbind = true;
   }

   /* xfd->dtype = DATA_STREAM; // is default */
   if ((result =
	xioopen_connect(xfd,
		      needbind?(struct sockaddr *)&us:NULL, uslen,
			(struct sockaddr *)&them, themlen,
		      opts, PF_UNIX, socktype?socktype:SOCK_STREAM, 0, false)) != 0) {
      if (errno == EPROTOTYPE) {
	 if (needbind) {
	    Unlink(us.un.sun_path);
	 }

	 /* ...res_opts[] */
	 applyopts(-1, opts, PH_INIT);
	 if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;

	 xfd->peersa = them;
	 xfd->salen = themlen;
	 if ((result =
	      _xioopen_dgram_sendto(needbind?&us:NULL, uslen,
				    opts, xioflags, xfd, groups, pf,
				    socktype?socktype:SOCK_DGRAM, 0))
	     != 0) {
	    return result;
	 }
	 xfd->dtype = XIODATA_RECVFROM;
      }
   }
   if ((result = _xio_openlate(xfd, opts)) < 0) {
      return result;
   }
   return 0;
}

#endif /* WITH_ABSTRACT_UNIXSOCKET */

/* returns information that can be used for constructing an environment
   variable describing the socket address.
   if idx is 0, this function writes "ADDR" into namebuff and the path into
   valuebuff, and returns 0 (which means that no more info is there).
   if idx is != 0, it returns -1
   namelen and valuelen contain the max. allowed length of output chars in the
   respective buffer.
   on error this function returns -1.
*/
int
xiosetsockaddrenv_unix(int idx, char *namebuff, size_t namelen,
		       char *valuebuff, size_t valuelen,
		       struct sockaddr_un *sa, socklen_t salen, int ipproto) {
   if (idx != 0) {
      return -1;
   }
   strcpy(namebuff, "ADDR");
   sockaddr_unix_info(sa, salen, valuebuff, valuelen);
   return 0;
}

#endif /* WITH_UNIX */