1 /* Datagram Socket Example
2 Copyright (C) 1991-2021 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 <stdlib.h>
21 #include <sys/socket.h>
22 #include <sys/un.h>
23
24 #define SERVER "/tmp/serversocket"
25 #define MAXMSG 512
26
27 int
main(void)28 main (void)
29 {
30 int sock;
31 char message[MAXMSG];
32 struct sockaddr_un name;
33 size_t size;
34 int nbytes;
35
36 /* Remove the filename first, it's ok if the call fails */
37 unlink (SERVER);
38
39 /* Make the socket, then loop endlessly. */
40 sock = make_named_socket (SERVER);
41 while (1)
42 {
43 /* Wait for a datagram. */
44 size = sizeof (name);
45 nbytes = recvfrom (sock, message, MAXMSG, 0,
46 (struct sockaddr *) & name, &size);
47 if (nbytes < 0)
48 {
49 perror ("recfrom (server)");
50 exit (EXIT_FAILURE);
51 }
52
53 /* Give a diagnostic message. */
54 fprintf (stderr, "Server: got message: %s\n", message);
55
56 /* Bounce the message back to the sender. */
57 nbytes = sendto (sock, message, nbytes, 0,
58 (struct sockaddr *) & name, size);
59 if (nbytes < 0)
60 {
61 perror ("sendto (server)");
62 exit (EXIT_FAILURE);
63 }
64 }
65 }
66