manual/examples/filecli.c

   1 /* Example of Reading Datagrams
   2    Copyright (C) 1991-2019 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU General Public License
   6    as published by the Free Software Foundation; either version 2
   7    of the License, or (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, see <https://www.gnu.org/licenses/>.
  16 */
  17
  18 #include <stdio.h>
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <stdlib.h>
  22 #include <sys/socket.h>
  23 #include <sys/un.h>
  24
  25 #define SERVER  "/tmp/serversocket"
  26 #define CLIENT  "/tmp/mysocket"
  27 #define MAXMSG  512
  28 #define MESSAGE "Yow!!! Are we having fun yet?!?"
  29
  30 int
  31 main (void)
  32 {
  33   extern int make_named_socket (const char *name);
  34   int sock;
  35   char message[MAXMSG];
  36   struct sockaddr_un name;
  37   size_t size;
  38   int nbytes;
  39
  40   /* Make the socket. */
  41   sock = make_named_socket (CLIENT);
  42
  43   /* Initialize the server socket address. */
  44   name.sun_family = AF_LOCAL;
  45   strcpy (name.sun_path, SERVER);
  46   size = strlen (name.sun_path) + sizeof (name.sun_family);
  47
  48   /* Send the datagram. */
  49   nbytes = sendto (sock, MESSAGE, strlen (MESSAGE) + 1, 0,
  50                    (struct sockaddr *) & name, size);
  51   if (nbytes < 0)
  52     {
  53       perror ("sendto (client)");
  54       exit (EXIT_FAILURE);
  55     }
  56
  57   /* Wait for a reply. */
  58   nbytes = recvfrom (sock, message, MAXMSG, 0, NULL, 0);
  59   if (nbytes < 0)
  60     {
  61       perror ("recfrom (client)");
  62       exit (EXIT_FAILURE);
  63     }
  64
  65   /* Print a diagnostic message. */
  66   fprintf (stderr, "Client: got message: %s\n", message);
  67
  68   /* Clean up. */
  69   remove (CLIENT);
  70   close (sock);
  71 }