doc/07.ipctut/ustreamread.c

.\" Copyright (c) 1986 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"     @(#)ustreamread.c       6.3 (Berkeley) 5/8/86
.\"
#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);
}