xiosocketpair.c - socat - Git at Google

 /* $Id$ */
 /* Copyright Gerhard Rieger 2007-2009 */
 /* Published under the GNU General Public License V.2, see file COPYING */

 /* this is the source of the internal xiosocketpair function */

 #include "xiosysincludes.h"
 #include "sycls.h"
 #include "compat.h"
 #include "error.h"
 #include "xio.h"


 #if defined(HAVE_DEV_PTMX)
 #  define PTMX "/dev/ptmx"	/* Linux */
 #elif HAVE_DEV_PTC
 #  define PTMX "/dev/ptc"	/* AIX */
 #endif

 #define MAXPTYNAMELEN 64

 int xiopty(int useptmx, int *ttyfdp, int *ptyfdp) {
    int ttyfd, ptyfd = -1;
    char ptyname[MAXPTYNAMELEN];
    struct termios termarg;

    if (useptmx) {
       if ((ptyfd = Open(PTMX, O_RDWR|O_NOCTTY, 0620)) < 0) {
 	 Warn1("open(\""PTMX"\", O_RDWR|O_NOCTTY, 0620): %s",
 	       strerror(errno));
 	 /*!*/
       } else {
 	 ;/*0 Info1("open(\""PTMX"\", O_RDWR|O_NOCTTY, 0620) -> %d", ptyfd);*/
       }
       if (ptyfd >= 0) {
 	 char *tn = NULL;

 	 /* we used PTMX before forking */
 	 /*0 extern char *ptsname(int);*/
 #if HAVE_GRANTPT	/* AIX, not Linux */
 	 if (Grantpt(ptyfd)/*!*/ < 0) {
 	    Warn2("grantpt(%d): %s", ptyfd, strerror(errno));
 	 }
 #endif /* HAVE_GRANTPT */
 #if HAVE_UNLOCKPT
 	 if (Unlockpt(ptyfd)/*!*/ < 0) {
 	    Warn2("unlockpt(%d): %s", ptyfd, strerror(errno));
 	 }
 #endif /* HAVE_UNLOCKPT */
 #if HAVE_PTSNAME	/* AIX, not Linux */
 	 if ((tn = Ptsname(ptyfd)) == NULL) {
 	    Warn2("ptsname(%d): %s", ptyfd, strerror(errno));
 	 } else {
 	    Notice1("PTY is %s", tn);
 	 }
 #endif /* HAVE_PTSNAME */
 #if 0
 	 if (tn == NULL) {
 	    /*! ttyname_r() */
 	    if ((tn = Ttyname(ptyfd)) == NULL) {
 	       Warn2("ttyname(%d): %s", ptyfd, strerror(errno));
 	    }
 	 }
 	 strncpy(ptyname, tn, MAXPTYNAMELEN);
 #endif
 	 if ((ttyfd = Open(tn, O_RDWR|O_NOCTTY, 0620)) < 0) {
 	    Warn2("open(\"%s\", O_RDWR|O_NOCTTY, 0620): %s", tn, strerror(errno));
 	 } else {
 	    /*0 Info2("open(\"%s\", O_RDWR|O_NOCTTY, 0620) -> %d", tn, ttyfd);*/
 	 }

 #ifdef I_PUSH
 	 /* Linux: I_PUSH def'd; pty: ioctl(, I_FIND, ...) -> -1 EINVAL */
 	 /* AIX:   I_PUSH def'd; pty: ioctl(, I_FIND, ...) -> 1 */
 	 /* SunOS: I_PUSH def'd; pty: ioctl(, I_FIND, ...) -> 0 */
 	 /* HP-UX: I_PUSH def'd; pty: ioctl(, I_FIND, ...) -> 0 */
 	 if (Ioctl(ttyfd, I_FIND, "ldterm") == 0) {
 	    Ioctl(ttyfd, I_PUSH, "ptem");		/* 0 */
 	    Ioctl(ttyfd, I_PUSH, "ldterm");		/* 0 */
 	    Ioctl(ttyfd, I_PUSH, "ttcompat");	/* HP-UX: -1 */
 	 }
 #endif
       }
    }
 #if HAVE_OPENPTY
    if (ptyfd < 0) {
       int result;
       if ((result = Openpty(&ptyfd, &ttyfd, ptyname, NULL, NULL)) < 0) {
 	 Error4("openpty(%p, %p, %p, NULL, NULL): %s",
 		&ptyfd, &ttyfd, ptyname, strerror(errno));
 	 return -1;
       }
       Notice1("PTY is %s", ptyname);
    }
 #endif /* HAVE_OPENPTY */

    if (Tcgetattr(ttyfd, &termarg) < 0) {
       Error3("tcgetattr(%d, %p): %s",
 	     ttyfd, &termarg, strerror(errno));
    }
 #if 0
    cfmakeraw(&termarg);
 #else
    /*!!! share code with xioopts.c raw,echo=0 */
    termarg.c_iflag &=
       ~(IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|INLCR|IGNCR|ICRNL|IXON|IXOFF
 #ifdef IUCLC
 	|IUCLC
 #endif
 	|IXANY|IMAXBEL);
    termarg.c_iflag |= (0);
    termarg.c_oflag &= ~(OPOST);
    termarg.c_oflag |= (0);
    termarg.c_cflag &= ~(0);
    termarg.c_cflag |= (0);
    termarg.c_lflag &= ~(ECHO|ECHONL|ISIG|ICANON
 #ifdef XCASE
 			|XCASE
 #endif
 			);
    termarg.c_lflag |= (0);
    termarg.c_cc[VMIN] = 1;
    termarg.c_cc[VTIME] = 0;
 #endif
    if (Tcsetattr(ttyfd, TCSADRAIN, &termarg) < 0) {
       Error3("tcsetattr(%d, TCSADRAIN, %p): %s",
 	     ttyfd, &termarg, strerror(errno));
    }

    *ttyfdp = ttyfd;
    *ptyfdp = ptyfd;
    return 0;
 }

 /* generates a socket pair; supports not only PF_UNIX but also PF_INET */
 int xiosocketpair2(int pf, int socktype, int protocol, int sv[2]) {
    int result;

    switch (pf) {
       struct sockaddr_in ssin, csin, xsin;	/* server, client, compare */
       socklen_t cslen, xslen;
       int sconn, slist, sserv;	/* socket FDs */

    case PF_UNIX:
       result = Socketpair(pf, socktype, protocol, sv);
       if (result < 0) {
 	 Error5("socketpair(%d, %d, %d, %p): %s",
 		pf, socktype, protocol, sv, strerror(errno));
 	 return -1;
       }
       break;
 #if LATER
    case PF_INET:
 #if 1 /*!!! Linux */
       ssin.sin_family = pf;
       ssin.sin_port = htons(1024+random()%(65536-1024));
       ssin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 #endif /*  */
       if ((s = Socket(pf, socktype, protocol)) < 0) {
 	 Error4("socket(%d, %d, %d): %s",
 		pf, socktype, protocol, strerror(errno));
       }
       if (Bind(s, (struct sockaddr *)&ssin, sizeof(ssin)) < 0) {
 	 Error6("bind(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
 		s, ssin.sin_family, ssin.sin_addr.s_addr, ssin.sin_port,
 		sizeof(ssin), strerror(errno));
       }
       if (Connect(s, (struct sockaddr *)&ssin, sizeof(ssin)) < 0) {
 	 Error6("connect(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
 		s, ssin.sin_family, ssin.sin_addr.s_addr, ssin.sin_port,
 		sizeof(ssin), strerror(errno));
 	 return -1;
       }
       break;
 #endif /* LATER */
    case PF_INET:
       ssin.sin_family = pf;
       ssin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
       if ((slist = Socket(pf, socktype, protocol)) < 0) {
 	 Error4("socket(%d, %d, %d): %s",
 		pf, socktype, protocol, strerror(errno));
       }
       while (true) {	/* find a port we can bind to */
 	 ssin.sin_port = htons(1024+random()%(65536-1024));
 	 if (Bind(slist, (struct sockaddr *)&ssin, sizeof(ssin)) == 0)  break;
 	 if (errno == EADDRINUSE) {
 	    Info6("bind(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
 		  slist, ssin.sin_family, ssin.sin_addr.s_addr,
 		  ntohs(ssin.sin_port), sizeof(ssin), strerror(errno));
 	    continue;
 	 }
 	 Error6("bind(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
 		slist, ssin.sin_family, ssin.sin_addr.s_addr, ssin.sin_port,
 		sizeof(ssin), strerror(errno));
 	 Close(slist);
 	 return -1;
       }
       Listen(slist, 0);
       if ((sconn = Socket(pf, socktype, protocol)) < 0) {
 	 Error4("socket(%d, %d, %d): %s",
 		pf, socktype, protocol, strerror(errno));
 	 Close(slist); return -1;
       }
       /* for testing race condition: Sleep(30); */
       if (Connect(sconn, (struct sockaddr *)&ssin, sizeof(ssin)) < 0) {
 	 Error6("connect(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
 		sconn, ssin.sin_family, ssin.sin_addr.s_addr,
 		ntohs(ssin.sin_port),
 		sizeof(ssin), strerror(errno));
 	 Close(slist); Close(sconn); return -1;
       }
       cslen = sizeof(csin);
       if (Getsockname(sconn, (struct sockaddr *)&csin, &cslen) < 0) {
 	 Error4("getsockname(%d, %p, %p): %s",
 		sconn, &csin, &cslen, strerror(errno));
 	 Close(slist); Close(sconn); return -1;
       }
       do {
 	 xslen = sizeof(xsin);
 	 if ((sserv = Accept(slist, (struct sockaddr *)&xsin, &xslen)) < 0) {
 	    Error4("accept(%d, %p, {"F_Zu"}): %s",
 		   slist, &csin, sizeof(xslen), strerror(errno));
 	    Close(slist); Close(sconn); return -1;
 	 }
 	 if (!memcmp(&csin, &xsin, cslen)) {
 	    break;	/* expected connection */
 	 }
 	 Warn4("unexpected connection to 0x%lx:%hu from 0x%lx:%hu",
 	       ntohl(ssin.sin_addr.s_addr), ntohs(ssin.sin_port),
 	       ntohl(xsin.sin_addr.s_addr), ntohs(xsin.sin_port));
       } while (true);
       Close(slist);
       sv[0] = sconn;
       sv[1] = sserv;
       break;
    default:
       Error1("xiosocketpair2(): pf=%u not implemented", pf);
       return -1;
    }
    return 0;
 }

 /*
    dual should only be != 0 when both directions are used
    returns 0 on success
  */
 int xiocommpair(int commtype, bool lefttoright, bool righttoleft,
 		int dual, xiofd_t *left, xiofd_t *right, ...) {
    va_list ap;
    int domain = -1, socktype = -1, protocol = -1;
    int useptmx = 0;
    /* arrays can be used with pipe(2) and socketpair(2): */
    int svlr[2] = {-1, -1};	/* left to right: rfd, wfd */
    int svrl[2] = {-1, -1};	/* right to left: rfd, wfd */

    /* get related parameters from parameter list */
    switch (commtype) {
    case XIOCOMM_SOCKETPAIR:
    case XIOCOMM_SOCKETPAIRS:
       va_start(ap, right);
       domain   = va_arg(ap, int);
       socktype = va_arg(ap, int);
       protocol = va_arg(ap, int);
       va_end(ap);
       break;
    case XIOCOMM_PTY:
    case XIOCOMM_PTYS:
       va_start(ap, right);
       useptmx = va_arg(ap, int);
       va_end(ap);
       break;
    default:
       break;
    }

    switch (commtype) {
    default: /* unspec */
       Warn1("internal: undefined communication type %d, defaulting to 0",
 	    commtype);
       commtype = 0;
       /*PASSTHROUGH*/
    case XIOCOMM_SOCKETPAIRS: /* two socketpairs - the default */
       if (lefttoright) {
 	 if (Socketpair(domain, socktype, protocol, svlr) < 0) {
 	    Error5("socketpair(%d, %d, %d, %p): %s",
 		   domain, socktype, protocol, svlr, strerror(errno));
 	 }
 	 Shutdown(svlr[0], SHUT_WR);
       }
       if (righttoleft) {
 	 if (Socketpair(domain, socktype, protocol, svrl) < 0) {
 	    Error5("socketpair(%d, %d, %d, %p): %s",
 		   domain, socktype, protocol, svrl, strerror(errno));
 	 }
 	 Shutdown(svrl[0], SHUT_WR);
       }
       left->single     = right->single     = false;
       left->dtype      = right->dtype      = XIODATA_STREAM;
       left->howtoshut  = right->howtoshut  = XIOSHUT_DOWN;
       left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
       break;

    case XIOCOMM_PTYS: /* two ptys in raw mode, EOF in canonical mode */
       if (lefttoright) {
 	 if (xiopty(useptmx, &svlr[0], &svlr[1]) < 0)  return -1;
 	 /* pty is write side, interpretes ^D in canonical mode */
       }
       if (righttoleft) {
 	 if (xiopty(useptmx, &svrl[0], &svrl[1]) < 0)  return -1;
       }
       left->single     = right->single     = false;
       left->dtype      = right->dtype      = XIODATA_PTY;
       left->howtoshut  = right->howtoshut  = XIOSHUT_PTYEOF;
       left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
       break;

    case XIOCOMM_SOCKETPAIR: /* one socketpair */
       if (Socketpair(domain, socktype, protocol, svlr) < 0) {
 	 Error5("socketpair(%d %d %d, %p): %s",
 		domain, socktype, protocol, svlr, strerror(errno));
 	 return -1;
       }
       left->single     = right->single     = true;
       left->dtype      = right->dtype      = XIODATA_STREAM;
       left->howtoshut  = right->howtoshut  = XIOSHUT_DOWN;
       left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
       break;

    case XIOCOMM_PTY: /* one pty in raw mode, EOF in canonical mode */
       if (xiopty(useptmx, &svlr[0], &svlr[1]) < 0)  return -1;
       left->single     = right->single     = true;
       left->dtype      = right->dtype      = XIODATA_PTY;
       left->howtoshut  = XIOSHUT_PTYEOF;
       right->howtoshut = XIOSHUT_CLOSE;
       left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
       break;

    case XIOCOMM_PIPES: /* two pipes */
       if (lefttoright) {
 	 if (Pipe(svlr) < 0) {
 	    Error2("pipe(%p): %s", svlr, strerror(errno));
 	    return -1;
 	 }
       }
       if (righttoleft) {
 	 if (Pipe(svrl) < 0) {
 	    Error2("pipe(%p): %s", svrl, strerror(errno));
 	    return -1;
 	 }
       }
       left->single     = right->single     = false;
       left->dtype      = right->dtype      = XIODATA_STREAM;
       left->howtoshut  = right->howtoshut  = XIOSHUT_CLOSE;
       left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
       break;

    case XIOCOMM_TCP:
    case XIOCOMM_TCP4: /* one TCP/IPv4 socket pair */
       if (xiosocketpair2(PF_INET, SOCK_STREAM, 0, svlr) < 0) {
 	 Error2("socketpair(PF_UNIX, PF_STREAM, 0, %p): %s",
 		svlr, strerror(errno));
 	 return -1;
       }
       left->single     = right->single     = true;
       left->dtype      = right->dtype      = XIODATA_STREAM;
       left->howtoshut  = right->howtoshut  = XIOSHUT_DOWN;
       left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
       break;
    }

    if (dual && left->single) {
       /* one pair */
       /* dual; we use different FDs for the channels to avoid conflicts
 	 (happened in dual exec) */
       if ((svrl[1] = Dup(svlr[0])) < 0) {
 	 Error2("dup(%d): %s", svrl[0], strerror(errno));
 	 return -1;
       }
       if ((svrl[0] = Dup(svlr[1])) < 0) {
 	 Error2("dup(%d): %s", svlr[1], strerror(errno));
 	 return -1;
       }
    } else if (left->single) {
       svrl[1] = svlr[0];
       svrl[0] = svlr[1];
    }

    /* usually they are not to be passed to exec'd child processes */
    if (lefttoright) {
       Fcntl_l(svlr[0], F_SETFD, 1);
       Fcntl_l(svlr[1], F_SETFD, 1);
    }
    if (righttoleft && (!left->single || dual)) {
       Fcntl_l(svrl[0], F_SETFD, 1);
       Fcntl_l(svrl[1], F_SETFD, 1);
    }

    left->rfd = svrl[0];
    left->wfd = svlr[1];
    right->rfd = svlr[0];
    right->wfd = svrl[1];
    Notice4("xiocommpair() -> [%d:%d], [%d:%d]",
 	   left->rfd, left->wfd, right->rfd, right->wfd);
    return 0;
 }
	/* $Id$ */
	/* Copyright Gerhard Rieger 2007-2009 */
	/* Published under the GNU General Public License V.2, see file COPYING */

	/* this is the source of the internal xiosocketpair function */

	#include "xiosysincludes.h"
	#include "sycls.h"
	#include "compat.h"
	#include "error.h"
	#include "xio.h"


	#if defined(HAVE_DEV_PTMX)
	# define PTMX "/dev/ptmx" /* Linux */
	#elif HAVE_DEV_PTC
	# define PTMX "/dev/ptc" /* AIX */
	#endif

	#define MAXPTYNAMELEN 64

	int xiopty(int useptmx, int ttyfdp, int ptyfdp) {
	int ttyfd, ptyfd = -1;
	char ptyname[MAXPTYNAMELEN];
	struct termios termarg;

	if (useptmx) {
	if ((ptyfd = Open(PTMX, O_RDWR\|O_NOCTTY, 0620)) < 0) {
	Warn1("open(\""PTMX"\", O_RDWR\|O_NOCTTY, 0620): %s",
	strerror(errno));
	/!/
	} else {
	;/0 Info1("open(\""PTMX"\", O_RDWR\|O_NOCTTY, 0620) -> %d", ptyfd);/
	}
	if (ptyfd >= 0) {
	char *tn = NULL;

	/* we used PTMX before forking */
	/0 extern char ptsname(int);*/
	#if HAVE_GRANTPT /* AIX, not Linux */
	if (Grantpt(ptyfd)/!/ < 0) {
	Warn2("grantpt(%d): %s", ptyfd, strerror(errno));
	}
	#endif /* HAVE_GRANTPT */
	#if HAVE_UNLOCKPT
	if (Unlockpt(ptyfd)/!/ < 0) {
	Warn2("unlockpt(%d): %s", ptyfd, strerror(errno));
	}
	#endif /* HAVE_UNLOCKPT */
	#if HAVE_PTSNAME /* AIX, not Linux */
	if ((tn = Ptsname(ptyfd)) == NULL) {
	Warn2("ptsname(%d): %s", ptyfd, strerror(errno));
	} else {
	Notice1("PTY is %s", tn);
	}
	#endif /* HAVE_PTSNAME */
	#if 0
	if (tn == NULL) {
	/! ttyname_r() /
	if ((tn = Ttyname(ptyfd)) == NULL) {
	Warn2("ttyname(%d): %s", ptyfd, strerror(errno));
	}
	}
	strncpy(ptyname, tn, MAXPTYNAMELEN);
	#endif
	if ((ttyfd = Open(tn, O_RDWR\|O_NOCTTY, 0620)) < 0) {
	Warn2("open(\"%s\", O_RDWR\|O_NOCTTY, 0620): %s", tn, strerror(errno));
	} else {
	/0 Info2("open(\"%s\", O_RDWR\|O_NOCTTY, 0620) -> %d", tn, ttyfd);/
	}

	#ifdef I_PUSH
	/* Linux: I_PUSH def'd; pty: ioctl(, I_FIND, ...) -> -1 EINVAL */
	/* AIX: I_PUSH def'd; pty: ioctl(, I_FIND, ...) -> 1 */
	/* SunOS: I_PUSH def'd; pty: ioctl(, I_FIND, ...) -> 0 */
	/* HP-UX: I_PUSH def'd; pty: ioctl(, I_FIND, ...) -> 0 */
	if (Ioctl(ttyfd, I_FIND, "ldterm") == 0) {
	Ioctl(ttyfd, I_PUSH, "ptem"); /* 0 */
	Ioctl(ttyfd, I_PUSH, "ldterm"); /* 0 */
	Ioctl(ttyfd, I_PUSH, "ttcompat"); /* HP-UX: -1 */
	}
	#endif
	}
	}
	#if HAVE_OPENPTY
	if (ptyfd < 0) {
	int result;
	if ((result = Openpty(&ptyfd, &ttyfd, ptyname, NULL, NULL)) < 0) {
	Error4("openpty(%p, %p, %p, NULL, NULL): %s",
	&ptyfd, &ttyfd, ptyname, strerror(errno));
	return -1;
	}
	Notice1("PTY is %s", ptyname);
	}
	#endif /* HAVE_OPENPTY */

	if (Tcgetattr(ttyfd, &termarg) < 0) {
	Error3("tcgetattr(%d, %p): %s",
	ttyfd, &termarg, strerror(errno));
	}
	#if 0
	cfmakeraw(&termarg);
	#else
	/!!! share code with xioopts.c raw,echo=0 /
	termarg.c_iflag &=
	~(IGNBRK\|BRKINT\|IGNPAR\|PARMRK\|INPCK\|ISTRIP\|INLCR\|IGNCR\|ICRNL\|IXON\|IXOFF
	#ifdef IUCLC
	\|IUCLC
	#endif
	\|IXANY\|IMAXBEL);
	termarg.c_iflag \|= (0);
	termarg.c_oflag &= ~(OPOST);
	termarg.c_oflag \|= (0);
	termarg.c_cflag &= ~(0);
	termarg.c_cflag \|= (0);
	termarg.c_lflag &= ~(ECHO\|ECHONL\|ISIG\|ICANON
	#ifdef XCASE
	\|XCASE
	#endif
	);
	termarg.c_lflag \|= (0);
	termarg.c_cc[VMIN] = 1;
	termarg.c_cc[VTIME] = 0;
	#endif
	if (Tcsetattr(ttyfd, TCSADRAIN, &termarg) < 0) {
	Error3("tcsetattr(%d, TCSADRAIN, %p): %s",
	ttyfd, &termarg, strerror(errno));
	}

	*ttyfdp = ttyfd;
	*ptyfdp = ptyfd;
	return 0;
	}

	/* generates a socket pair; supports not only PF_UNIX but also PF_INET */
	int xiosocketpair2(int pf, int socktype, int protocol, int sv[2]) {
	int result;

	switch (pf) {
	struct sockaddr_in ssin, csin, xsin; /* server, client, compare */
	socklen_t cslen, xslen;
	int sconn, slist, sserv; /* socket FDs */

	case PF_UNIX:
	result = Socketpair(pf, socktype, protocol, sv);
	if (result < 0) {
	Error5("socketpair(%d, %d, %d, %p): %s",
	pf, socktype, protocol, sv, strerror(errno));
	return -1;
	}
	break;
	#if LATER
	case PF_INET:
	#if 1 /!!! Linux /
	ssin.sin_family = pf;
	ssin.sin_port = htons(1024+random()%(65536-1024));
	ssin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
	#endif /* */
	if ((s = Socket(pf, socktype, protocol)) < 0) {
	Error4("socket(%d, %d, %d): %s",
	pf, socktype, protocol, strerror(errno));
	}
	if (Bind(s, (struct sockaddr *)&ssin, sizeof(ssin)) < 0) {
	Error6("bind(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
	s, ssin.sin_family, ssin.sin_addr.s_addr, ssin.sin_port,
	sizeof(ssin), strerror(errno));
	}
	if (Connect(s, (struct sockaddr *)&ssin, sizeof(ssin)) < 0) {
	Error6("connect(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
	s, ssin.sin_family, ssin.sin_addr.s_addr, ssin.sin_port,
	sizeof(ssin), strerror(errno));
	return -1;
	}
	break;
	#endif /* LATER */
	case PF_INET:
	ssin.sin_family = pf;
	ssin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
	if ((slist = Socket(pf, socktype, protocol)) < 0) {
	Error4("socket(%d, %d, %d): %s",
	pf, socktype, protocol, strerror(errno));
	}
	while (true) { /* find a port we can bind to */
	ssin.sin_port = htons(1024+random()%(65536-1024));
	if (Bind(slist, (struct sockaddr *)&ssin, sizeof(ssin)) == 0) break;
	if (errno == EADDRINUSE) {
	Info6("bind(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
	slist, ssin.sin_family, ssin.sin_addr.s_addr,
	ntohs(ssin.sin_port), sizeof(ssin), strerror(errno));
	continue;
	}
	Error6("bind(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
	slist, ssin.sin_family, ssin.sin_addr.s_addr, ssin.sin_port,
	sizeof(ssin), strerror(errno));
	Close(slist);
	return -1;
	}
	Listen(slist, 0);
	if ((sconn = Socket(pf, socktype, protocol)) < 0) {
	Error4("socket(%d, %d, %d): %s",
	pf, socktype, protocol, strerror(errno));
	Close(slist); return -1;
	}
	/* for testing race condition: Sleep(30); */
	if (Connect(sconn, (struct sockaddr *)&ssin, sizeof(ssin)) < 0) {
	Error6("connect(%d, {%u, 0x%x:%u}, "F_Zu"): %s",
	sconn, ssin.sin_family, ssin.sin_addr.s_addr,
	ntohs(ssin.sin_port),
	sizeof(ssin), strerror(errno));
	Close(slist); Close(sconn); return -1;
	}
	cslen = sizeof(csin);
	if (Getsockname(sconn, (struct sockaddr *)&csin, &cslen) < 0) {
	Error4("getsockname(%d, %p, %p): %s",
	sconn, &csin, &cslen, strerror(errno));
	Close(slist); Close(sconn); return -1;
	}
	do {
	xslen = sizeof(xsin);
	if ((sserv = Accept(slist, (struct sockaddr *)&xsin, &xslen)) < 0) {
	Error4("accept(%d, %p, {"F_Zu"}): %s",
	slist, &csin, sizeof(xslen), strerror(errno));
	Close(slist); Close(sconn); return -1;
	}
	if (!memcmp(&csin, &xsin, cslen)) {
	break; /* expected connection */
	}
	Warn4("unexpected connection to 0x%lx:%hu from 0x%lx:%hu",
	ntohl(ssin.sin_addr.s_addr), ntohs(ssin.sin_port),
	ntohl(xsin.sin_addr.s_addr), ntohs(xsin.sin_port));
	} while (true);
	Close(slist);
	sv[0] = sconn;
	sv[1] = sserv;
	break;
	default:
	Error1("xiosocketpair2(): pf=%u not implemented", pf);
	return -1;
	}
	return 0;
	}

	/*
	dual should only be != 0 when both directions are used
	returns 0 on success
	*/
	int xiocommpair(int commtype, bool lefttoright, bool righttoleft,
	int dual, xiofd_t left, xiofd_t right, ...) {
	va_list ap;
	int domain = -1, socktype = -1, protocol = -1;
	int useptmx = 0;
	/* arrays can be used with pipe(2) and socketpair(2): */
	int svlr[2] = {-1, -1}; /* left to right: rfd, wfd */
	int svrl[2] = {-1, -1}; /* right to left: rfd, wfd */

	/* get related parameters from parameter list */
	switch (commtype) {
	case XIOCOMM_SOCKETPAIR:
	case XIOCOMM_SOCKETPAIRS:
	va_start(ap, right);
	domain = va_arg(ap, int);
	socktype = va_arg(ap, int);
	protocol = va_arg(ap, int);
	va_end(ap);
	break;
	case XIOCOMM_PTY:
	case XIOCOMM_PTYS:
	va_start(ap, right);
	useptmx = va_arg(ap, int);
	va_end(ap);
	break;
	default:
	break;
	}

	switch (commtype) {
	default: /* unspec */
	Warn1("internal: undefined communication type %d, defaulting to 0",
	commtype);
	commtype = 0;
	/PASSTHROUGH/
	case XIOCOMM_SOCKETPAIRS: /* two socketpairs - the default */
	if (lefttoright) {
	if (Socketpair(domain, socktype, protocol, svlr) < 0) {
	Error5("socketpair(%d, %d, %d, %p): %s",
	domain, socktype, protocol, svlr, strerror(errno));
	}
	Shutdown(svlr[0], SHUT_WR);
	}
	if (righttoleft) {
	if (Socketpair(domain, socktype, protocol, svrl) < 0) {
	Error5("socketpair(%d, %d, %d, %p): %s",
	domain, socktype, protocol, svrl, strerror(errno));
	}
	Shutdown(svrl[0], SHUT_WR);
	}
	left->single = right->single = false;
	left->dtype = right->dtype = XIODATA_STREAM;
	left->howtoshut = right->howtoshut = XIOSHUT_DOWN;
	left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
	break;

	case XIOCOMM_PTYS: /* two ptys in raw mode, EOF in canonical mode */
	if (lefttoright) {
	if (xiopty(useptmx, &svlr[0], &svlr[1]) < 0) return -1;
	/* pty is write side, interpretes ^D in canonical mode */
	}
	if (righttoleft) {
	if (xiopty(useptmx, &svrl[0], &svrl[1]) < 0) return -1;
	}
	left->single = right->single = false;
	left->dtype = right->dtype = XIODATA_PTY;
	left->howtoshut = right->howtoshut = XIOSHUT_PTYEOF;
	left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
	break;

	case XIOCOMM_SOCKETPAIR: /* one socketpair */
	if (Socketpair(domain, socktype, protocol, svlr) < 0) {
	Error5("socketpair(%d %d %d, %p): %s",
	domain, socktype, protocol, svlr, strerror(errno));
	return -1;
	}
	left->single = right->single = true;
	left->dtype = right->dtype = XIODATA_STREAM;
	left->howtoshut = right->howtoshut = XIOSHUT_DOWN;
	left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
	break;

	case XIOCOMM_PTY: /* one pty in raw mode, EOF in canonical mode */
	if (xiopty(useptmx, &svlr[0], &svlr[1]) < 0) return -1;
	left->single = right->single = true;
	left->dtype = right->dtype = XIODATA_PTY;
	left->howtoshut = XIOSHUT_PTYEOF;
	right->howtoshut = XIOSHUT_CLOSE;
	left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
	break;

	case XIOCOMM_PIPES: /* two pipes */
	if (lefttoright) {
	if (Pipe(svlr) < 0) {
	Error2("pipe(%p): %s", svlr, strerror(errno));
	return -1;
	}
	}
	if (righttoleft) {
	if (Pipe(svrl) < 0) {
	Error2("pipe(%p): %s", svrl, strerror(errno));
	return -1;
	}
	}
	left->single = right->single = false;
	left->dtype = right->dtype = XIODATA_STREAM;
	left->howtoshut = right->howtoshut = XIOSHUT_CLOSE;
	left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
	break;

	case XIOCOMM_TCP:
	case XIOCOMM_TCP4: /* one TCP/IPv4 socket pair */
	if (xiosocketpair2(PF_INET, SOCK_STREAM, 0, svlr) < 0) {
	Error2("socketpair(PF_UNIX, PF_STREAM, 0, %p): %s",
	svlr, strerror(errno));
	return -1;
	}
	left->single = right->single = true;
	left->dtype = right->dtype = XIODATA_STREAM;
	left->howtoshut = right->howtoshut = XIOSHUT_DOWN;
	left->howtoclose = right->howtoclose = XIOCLOSE_CLOSE;
	break;
	}

	if (dual && left->single) {
	/* one pair */
	/* dual; we use different FDs for the channels to avoid conflicts
	(happened in dual exec) */
	if ((svrl[1] = Dup(svlr[0])) < 0) {
	Error2("dup(%d): %s", svrl[0], strerror(errno));
	return -1;
	}
	if ((svrl[0] = Dup(svlr[1])) < 0) {
	Error2("dup(%d): %s", svlr[1], strerror(errno));
	return -1;
	}
	} else if (left->single) {
	svrl[1] = svlr[0];
	svrl[0] = svlr[1];
	}

	/* usually they are not to be passed to exec'd child processes */
	if (lefttoright) {
	Fcntl_l(svlr[0], F_SETFD, 1);
	Fcntl_l(svlr[1], F_SETFD, 1);
	}
	if (righttoleft && (!left->single \|\| dual)) {
	Fcntl_l(svrl[0], F_SETFD, 1);
	Fcntl_l(svrl[1], F_SETFD, 1);
	}

	left->rfd = svrl[0];
	left->wfd = svlr[1];
	right->rfd = svlr[0];
	right->wfd = svrl[1];
	Notice4("xiocommpair() -> [%d:%d], [%d:%d]",
	left->rfd, left->wfd, right->rfd, right->wfd);
	return 0;
	}