xref: /freebsd/share/doc/psd/20.ipctut/strchkread.c (revision 97759ccc715c4b365432c16d763c50eecfcb1100)

.\" Copyright (c) 1986, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#define TRUE 1

/*
 * This program uses select() to check that someone is trying to connect
 * before calling accept().
 */

main()
{
	int sock, length;
	struct sockaddr_in server;
	int msgsock;
	char buf[1024];
	int rval;
	fd_set ready;
	struct timeval to;

	/* Create socket */
	sock = socket(AF_INET, SOCK_STREAM, 0);
	if (sock < 0) {
		perror("opening stream socket");
		exit(1);
	}
	/* Name socket using wildcards */
	server.sin_family = AF_INET;
	server.sin_addr.s_addr = INADDR_ANY;
	server.sin_port = 0;
	if (bind(sock, &server, sizeof(server))) {
		perror("binding stream socket");
		exit(1);
	}
	/* Find out assigned port number and print it out */
	length = sizeof(server);
	if (getsockname(sock, &server, &length)) {
		perror("getting socket name");
		exit(1);
	}
	printf("Socket has port #%d\en", ntohs(server.sin_port));

	/* Start accepting connections */
	listen(sock, 5);
	do {
		FD_ZERO(&ready);
		FD_SET(sock, &ready);
		to.tv_sec = 5;
		if (select(sock + 1, &ready, 0, 0, &to) < 0) {
			perror("select");
			continue;
		}
		if (FD_ISSET(sock, &ready)) {
			msgsock = accept(sock, (struct sockaddr *)0, (int *)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);
		} else
			printf("Do something else\en");
	} while (TRUE);
}