Re: scotty/tkined on SCO Unix

Erik Schoenfelder (schoenfr@sol)
Fri, 8 Apr 94 19:54:26 +0200

Hi!

> "S. Kent Hamilton" <kenth@scssa.ops.scscom.com>:

SKH> This is a problem on SCO (and many other Intel Unix's) they don't have
SKH> socketpair. They don't have unix sockets. Most of the stuff is done
SKH> via named pipes, or SysV ipc.

*Smile* Time to take a look at Linux. A intel box with socketpairs ;-)

> Maybe a workaroud would be a socketpair() replacement which creates
> two inet domain sockets, bound to diffrent ports, connects them via
> accept/connect and uses this connection after a fork. But i am not
> sure, if this would be usable.

SKH> This is what I had in mind trying. I've never tried it before
SKH> but I can't see why it wouldn't work. If you have suggestions
SKH> for implimenting it please send 'em along, I'm a sysadmin not
SKH> a coder.... :-)

Well, maybe the sysadmins are the better coders ? The users are ever
playing and never hacking... ;-)

Anyway, please try the ``inet_socketpair()'' function below as a
replacement with AF_INET domain parameter. Maybe its the shot that
hits the spot.

It seems to work with SunOS 4.1.x and Linux 1.0.

Thanks, Erik

---
/*
 * socketpair-example3.c:				April 1994
 * (schoenfr)
 *
 * simple socketpair replacement for AF_INET domain.
 */


#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>




/* #define TEST_STANDALONE		/* define for a test version */




/*
 * use	
 *	inet_socketpair (AF_INET, SOCK_STREAM, 0, xv)
 * as	
 *	socketpair (AF_UNIX, SOCK_STREAM, 0, xv)
 * replacement.
 */


static int
inet_socketpair (d, type, protocol, sv)
 int d, type, protocol;
 int sv[2];
{
    struct sockaddr_in addr1, addr2, addr3;
    int addr3_len = sizeof (addr3);
    int fd, rc;
    static int port_no = 2345;			/* XXX: ok ? */


    if (d != AF_INET || type != SOCK_STREAM || protocol)
    {
	fprintf (stderr, "** bad param in inet_socketpair.\n");
	return -1;
    }


    if ((sv [0] = socket (AF_INET, SOCK_STREAM, 0)) < 0
	|| (sv [1] = socket (AF_INET, SOCK_STREAM, 0)) < 0)
    {
	perror ("** cannot create sockets; reason");
	return -1;
    }


    addr1.sin_port = htons (port_no);
    addr1.sin_family = AF_INET;
    addr1.sin_addr.s_addr = 0;


    while ((rc = bind (sv[0], (struct sockaddr *) &addr1, sizeof (addr1))) < 0
	   && errno == EADDRINUSE)
	addr1.sin_port = htons (++port_no);


    if (rc < 0)
    {
	perror ("** cannot bind; reason");
	return -1;
    }
    
    if (listen (sv[0], 1) < 0)
    {
        perror ("** cannot listen; reason");
        return -1;
    }


    addr2.sin_port = htons (port_no);
    addr2.sin_family = AF_INET;
    addr2.sin_addr.s_addr = htonl (INADDR_LOOPBACK);


    if (connect (sv[1], (struct sockaddr *) &addr2, sizeof (addr2)) < 0)
    {
        perror ("** cannot connect; reason");
        return -1;
    }
    
    if ((fd = accept (sv[0], (struct sockaddr *) &addr3, &addr3_len)) < 0)
    {
	perror ("** cannot accept; reason");
        return -1;
    }


    if (close (sv[0]) < 0)
    {
	perror ("** cannot close; reason");
        return -1;
    }


    sv[0] = fd;


/**    printf ("* returning sv[0]=%d  sv[1]=%d\n", sv[0], sv[1]); **/


    /* okey dokey mom */
    return 0;
}




#ifdef TEST_STANDALONE


/*
 * simple test;    compile with  	cc socketpair-example3.c
 * 		   run as 		./a.out
 * and expect a 
 *		   ** got reply `hi nase\n''...
 * as reply (with the newline done).
 */




/* resolver tasks socketpair: */
static int xv [2];




static void
run_child (cmd)
char *cmd;
{
    int child;


#if 1
    if (inet_socketpair (AF_INET, SOCK_STREAM, 0, xv) < 0)
#else
    if (socketpair (AF_UNIX, SOCK_STREAM, 0, xv) < 0)
#endif
    {
	fprintf (stderr, "cannot create fake socketpair\n");
	exit (1);
    }
    
    child = fork ();
    if (child < 0)
    {
	perror ("cannot for a child; reason");
	exit (0);
    }
    if (child)
    {
	close (xv [0]);
	dup2 (xv [1], 0);
	dup2 (xv [1], 1);
	execl ("/bin/sh", "sh", "-c", cmd, (char *) 0);
	perror ("cannot execute child; reason");
	exit (1);
    }
    else {
	close (xv [1]);
    }
}




static void
run_cmd (str)
char *str;
{
    char tmp [128];
    int i, n;
    
    if (strlen (str) != write (xv [0], str, strlen (str)))
    {
	perror ("cannot write message to child; reason");
	exit (1);
    }
    
    n = read (xv [0], tmp, 128);
    if (n < 0)
    {
	perror ("cannot read message from child; reason");
	exit (1);
    }
    
    printf ("** got reply `");
    for (i = 0; i < n; i++)
	putchar (tmp [i]);
    printf ("'...\n");
}




main ()
{
    /* hopefully the command does unbuffered io ;-) */
    run_child ("/bin/cat");
    run_cmd ("hi nase\n");
}


#endif /* TEST_STANDALONE */


/* end if socketpair-example3.c */