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

   1 .\"     $NetBSD: ustreamread.c,v 1.2 1998/01/09 06:55:08 perry Exp $
   2 .\"
   3 .\" Copyright (c) 1986, 1993
   4 .\"     The Regents of the University of California.  All rights reserved.
   5 .\"
   6 .\" Redistribution and use in source and binary forms, with or without
   7 .\" modification, are permitted provided that the following conditions
   8 .\" are met:
   9 .\" 1. Redistributions of source code must retain the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer.
  11 .\" 2. Redistributions in binary form must reproduce the above copyright
  12 .\"    notice, this list of conditions and the following disclaimer in the
  13 .\"    documentation and/or other materials provided with the distribution.
  14 .\" 3. Neither the name of the University nor the names of its contributors
  15 .\"    may be used to endorse or promote products derived from this software
  16 .\"    without specific prior written permission.
  17 .\"
  18 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  19 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28 .\" SUCH DAMAGE.
  29 .\"
  30 .\"     @(#)ustreamread.c       8.1 (Berkeley) 6/8/93
  31 .\"
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <sys/un.h>
  35 #include <stdio.h>
  36
  37 #define NAME "socket"
  38
  39 /*
  40  * This program creates a socket in the UNIX domain and binds a name to it.
  41  * After printing the socket's name it begins a loop. Each time through the
  42  * loop it accepts a connection and prints out messages from it.  When the
  43  * connection breaks, or a termination message comes through, the program
  44  * accepts a new connection.
  45  */
  46 main()
  47 {
  48         int sock, msgsock, rval;
  49         struct sockaddr_un server;
  50         char buf[1024];
  51
  52         /* Create socket */
  53         sock = socket(AF_UNIX, SOCK_STREAM, 0);
  54         if (sock < 0) {
  55                 perror("opening stream socket");
  56                 exit(1);
  57         }
  58         /* Name socket using file system name */
  59         server.sun_family = AF_UNIX;
  60         strcpy(server.sun_path, NAME);
  61         if (bind(sock, &server, sizeof(struct sockaddr_un))) {
  62                 perror("binding stream socket");
  63                 exit(1);
  64         }
  65         printf("Socket has name %s\en", server.sun_path);
  66         /* Start accepting connections */
  67         listen(sock, 5);
  68         for (;;) {
  69                 msgsock = accept(sock, 0, 0);
  70                 if (msgsock == -1)
  71                         perror("accept");
  72                 else do {
  73                         bzero(buf, sizeof(buf));
  74                         if ((rval = read(msgsock, buf, 1024)) < 0)
  75                                 perror("reading stream message");
  76                         else if (rval == 0)
  77                                 printf("Ending connection\en");
  78                         else
  79                                 printf("-->%s\en", buf);
  80                 } while (rval > 0);
  81                 close(msgsock);
  82         }
  83         /*
  84          * The following statements are not executed, because they follow an
  85          * infinite loop.  However, most ordinary programs will not run
  86          * forever.  In the UNIX domain it is necessary to tell the file
  87          * system that one is through using NAME.  In most programs one uses
  88          * the call unlink() as below. Since the user will have to kill this
  89          * program, it will be necessary to remove the name by a command from
  90          * the shell.
  91          */
  92         close(sock);
  93         unlink(NAME);
  94 }