NetBSD/share/doc/psd/20.ipctut/ustreamread.c

.\"	$NetBSD: ustreamread.c,v 1.2 1998/01/09 06:55:08 perry Exp $
.\"
.\" Copyright (c) 1986, 1993
.\"	The Regents of the University of California.  All rights reserved.
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.\"    notice, this list of conditions and the following disclaimer in the
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.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
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.\"	@(#)ustreamread.c	8.1 (Berkeley) 6/8/93
.\"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>

#define NAME "socket"

/*
 * This program creates a socket in the UNIX domain and binds a name to it. 
 * After printing the socket's name it begins a loop. Each time through the
 * loop it accepts a connection and prints out messages from it.  When the
 * connection breaks, or a termination message comes through, the program
 * accepts a new connection. 
 */
main()
{
	int sock, msgsock, rval;
	struct sockaddr_un server;
	char buf[1024];

	/* Create socket */
	sock = socket(AF_UNIX, SOCK_STREAM, 0);
	if (sock < 0) {
		perror("opening stream socket");
		exit(1);
	}
	/* Name socket using file system name */
	server.sun_family = AF_UNIX;
	strcpy(server.sun_path, NAME);
	if (bind(sock, &server, sizeof(struct sockaddr_un))) {
		perror("binding stream socket");
		exit(1);
	}
	printf("Socket has name %s\en", server.sun_path);
	/* Start accepting connections */
	listen(sock, 5);
	for (;;) {
		msgsock = accept(sock, 0, 0);
		if (msgsock == -1)
			perror("accept");
		else do {
			bzero(buf, sizeof(buf));
			if ((rval = read(msgsock, buf, 1024)) < 0)
				perror("reading stream message");
			else if (rval == 0)
				printf("Ending connection\en");
			else
				printf("-->%s\en", buf);
		} while (rval > 0);
		close(msgsock);
	}
	/*
	 * The following statements are not executed, because they follow an
	 * infinite loop.  However, most ordinary programs will not run
	 * forever.  In the UNIX domain it is necessary to tell the file
	 * system that one is through using NAME.  In most programs one uses
	 * the call unlink() as below. Since the user will have to kill this
	 * program, it will be necessary to remove the name by a command from
	 * the shell. 
	 */
	close(sock);
	unlink(NAME);
}