2005-11-08 Carl Worth <cworth@cworth.org>

[ttt] / src / ttt-server.c

diff --git a/src/ttt-server.c b/src/ttt-server.c
index b42db7a95064811b95fff78b4f0070236b4fe69c..a248fa1a789b0a22f20db04551f0f531aaf472d5 100644 (file)
--- a/src/ttt-server.c
+++ b/src/ttt-server.c
@@ -21,15 +21,156 @@
 
 #include "ttt.h"
 
+static ttt_status_t
+_sockaddr_init (struct sockaddr_in     *addr,
+               const char              *host,
+               const char              *port)
+{
+    struct hostent *hostent;
+    struct servent *servent;
+    char *endptr;
+    long port_long;
+    uint16_t port_short;
+
+    addr->sin_family = AF_INET;
+
+    hostent = gethostbyname (host);
+    if (hostent == NULL)
+    {
+       fprintf (stderr, "Error: Lookup failed for host %s: %s\n",
+                host, hstrerror (h_errno));
+       return TTT_STATUS_FAILURE;
+    }
+    memcpy (&addr->sin_addr.s_addr, hostent->h_addr_list[0], 
+           sizeof (addr->sin_addr.s_addr));
+
+    assert (*port != '\0');
+    port_long = strtol (port, &endptr, 10);
+    if (*endptr == '\0')
+    {
+       /* Numeric port*/
+       if (port_long <= 0 || port_long >= (1 << 16)) {
+           fprintf (stderr, "Error: Port %ld out of range.\n", port_long);
+           return TTT_STATUS_FAILURE;
+       }
+       port_short = port_long;
+       addr->sin_port = htons (port_short);
+    } else {
+       /* Named port */
+       servent = getservbyname (port, "tcp");
+       if (port == NULL) {
+           fprintf (stderr, "Error: Lookup failed for port %s: %s\n",
+                    port, hstrerror (h_errno));
+           return TTT_STATUS_FAILURE;
+       }
+       addr->sin_port = servent->s_port;
+    }
+
+    return TTT_STATUS_SUCCESS;
+}
+
+static int
+_wait_for_connection (int listen_socket)
+{
+    fd_set read_set;
+    int num_selected;
+    int flags, err;
+    int connected_socket;
+
+    FD_ZERO (&read_set);
+    FD_SET (listen_socket, &read_set);
+
+    while (1) {
+       num_selected = select (listen_socket + 1,
+                              &read_set, NULL, NULL,
+                              NULL);
+
+       flags = fcntl (listen_socket, F_GETFL);
+       flags |= O_NONBLOCK;
+       xfcntl (listen_socket, F_SETFL, flags);
+
+       connected_socket = accept (listen_socket, 0, 0);
+       err = errno;
+
+       flags &= ~O_NONBLOCK;
+       xfcntl (listen_socket, F_SETFL, flags);
+
+       if (connected_socket != -1)
+           return connected_socket;
+
+       if (err == EWOULDBLOCK || err == EAGAIN)
+           continue;
+
+       fprintf (stderr, "Error: accept failed: %s. Aborting.\n",
+                strerror (err));
+       exit (1);
+    }
+}
+
+static const char *WELCOME_MESSAGE = 
+"Welcome to ttt-server. So far, this program is simply a demonstration\n"
+"of a one-shot TCP/IP server. The server is currently listening on:\n"
+"\n    %s:%s\n"
+"\nTo test this program, simply connect a client to that host and port.\n"
+"For example:\n"
+"\n    telnet %s %s\n"
+"\nOnce you have connected a client, the server will echo any characters\n"
+"it receives back to the client as well as to stdout.\n"
+"\nNote that to terminate the telnet client you type Control-], then\n"
+"<Enter>, then \"close\" (and <Enter>) at the \"telnet> \" prompt.\n"
+"\nHave fun!\n"
+"-Carl\n"
+"\nPS. By one-shot, I mean that the server will only accept a connection\n"
+"from a single client, and the server will exit when that client disconnects\n"
+"To test the server again, you will need to manually restart it again.\n"
+"Extending the server to start listening again, or to handle multiple\n"
+"clients simultaneously would both be fun projects for a motivated\n"
+"student (as would writing a custom client program).\n\n";
+
 int 
 main (int argc, char **argv)
 {
     ttt_args_t args;
     int args_first;
+    int listen_socket, connected_socket;
+    struct sockaddr_in addr;
 
     ttt_args_parse (&args, argc, argv, &args_first);
 
-    /* XXX: insert code here */
+    listen_socket = xsocket (PF_INET, SOCK_STREAM, 0);
+
+#define HOST "localhost"
+#define PORT "5534"
+
+    _sockaddr_init (&addr, HOST, PORT);
+
+#ifdef SO_REUSEADDR
+    {
+       int one = 1;
+       setsockopt (listen_socket, SOL_SOCKET,
+                   SO_REUSEADDR, (char *) &one, sizeof (int));
+    }
+#endif
+
+    xbind (listen_socket, (struct sockaddr *) &addr, sizeof (addr));
+
+    xlisten (listen_socket, SOMAXCONN);
+
+    printf (WELCOME_MESSAGE, HOST, PORT, HOST, PORT);
+
+    connected_socket = _wait_for_connection (listen_socket);
+
+#define BUF_SIZE 1024
+
+    while (1) {
+       char buf[BUF_SIZE];
+       int cnt;
+       cnt = read (connected_socket, buf, BUF_SIZE);
+       if (cnt == 0)
+           break;
+       write (0, buf, cnt);
+       write (connected_socket, buf, cnt);
+    }
 
     return 0;
 }