source: fact/tools/SocketClient/ExampleServer.cc@ 18233

Last change on this file since 18233 was 205, checked in by ogrimm, 15 years ago
Added example socket server code (taken from drsdaq)
File size: 3.0 KB
Line 
1/********************************************************************\
2
3 Example socket server
4
5 Code from original drsdaq socket thread
6
7 This code will block execution in the accept() and read() socket function
8 while waiting for a connection or data. To terminate, these blocking functions
9 must be interrupted by raising a signal (e.g. SIGUSR1). Testing on errno=EINTR
10 then indicates this.
11
12 Oliver Grimm, May 2010
13
14\********************************************************************/
15
16#define PORT 2000 // TCP/IP port
17
18void CCCommand() {
19
20 int ServerSocket,ConnectionSocket,ReadResult;
21 struct sockaddr_in SocketAddress, ClientAddress;
22 struct hostent *ClientName;
23 socklen_t SizeClientAddress=sizeof(ClientAddress);
24 char Command[MAX_COM_SIZE];
25
26 // Set up server socket
27 if ((ServerSocket = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
28 printf("Could not open server socket (%s)\n", strerror(errno));
29 return;
30 }
31 // Allows immediate reuse of socket after closing (circumvents TIME_WAIT)
32 int Value=1;
33 if (setsockopt(ServerSocket, SOL_SOCKET, SO_REUSEADDR, (char *) &Value, sizeof (Value)) == -1) {
34 printf("Warning: Could not set server socket option SO_REUSEADDR (%s)\n", strerror(errno));
35 }
36
37 SocketAddress.sin_family = PF_INET;
38 SocketAddress.sin_port = htons((unsigned short) PORT);
39 SocketAddress.sin_addr.s_addr = INADDR_ANY;
40
41 if (bind(ServerSocket, (struct sockaddr *) &SocketAddress, sizeof(SocketAddress)) == -1)
42 {
43 printf("Could not bind port to socket (%s)\n", strerror(errno));
44 close(ServerSocket);
45 return;
46 }
47 if (listen(ServerSocket, 0) == -1) {
48 printf("Could not set socket to listening (%s)\n", strerror(errno));
49 close(ServerSocket);
50 return;
51 }
52
53 // Looping to wait for incoming connection
54 while (true) {
55 if ((ConnectionSocket = accept(ServerSocket, (struct sockaddr *) &ClientAddress, &SizeClientAddress)) == -1) {
56 if (errno!=EINTR) printf("Failed to accept incoming connection (%s)\n", strerror(errno));
57 close(ServerSocket);
58 return;
59 }
60
61 ClientName = gethostbyaddr((char *) &ClientAddress.sin_addr ,sizeof(struct sockaddr_in),AF_INET);
62 printf("Connected to client at %s (%s).\n", inet_ntoa(ClientAddress.sin_addr), ClientName!=NULL ? ClientName->h_name:"name unknown");
63
64 // Looping as long as client exists and program not terminated
65 while (true) {
66
67 // Try to read command from socket
68 memset(Command, 0, sizeof(Command));
69 ReadResult = read(ConnectionSocket, Command, MAX_COM_SIZE);
70 if (ReadResult == 0) break; // Client not exisiting anymore
71 if (ReadResult == -1) {
72 if (errno!=EINTR) printf("Error read from socket (%s)\n", strerror(errno));
73 break;
74 }
75 if (Command[strlen(Command)-1]=='\n') Command[strlen(Command)-1]='\0'; // Remove trailing newline
76
77 printf("Received command '%s'\n", Command);
78 }
79
80 printf("Disconnected from client.\n");
81 close(ConnectionSocket);
82 }
83 close(ServerSocket);
84 printf("Server socket closed.\n");
85}
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