2005-11-09 Carl Worth <cworth@cworth.org>

[ttt] / src / ttt-socket.c

diff --git a/src/ttt-socket.c b/src/ttt-socket.c
new file mode 100644 (file)
index 0000000..765cab1
--- /dev/null
+++ b/src/ttt-socket.c
@@ -0,0 +1,156 @@
+/* ttt-socket.c - Simple interface for creating sockets.
+ *
+ * Copyright © 2005 Carl Worth
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Author: Carl Worth <cworth@cworth.org>
+ */
+
+#include "ttt-socket.h"
+
+#include <netinet/ip.h>
+#include <netdb.h>
+
+/* Initialize a TCP/IP address structure with the given host and port.
+ *
+ * Lookup for host (e.g. /etc/hosts and DNA) and port (e.g /etc/services)
+ * will be performed if necessary.
+ *
+ * A special host value of "0.0.0.0" may be used to prepare a server
+ * socket to bind to all available addresses.
+ *
+ * Errors: If any lookup error occurs, this function will not return.
+ */
+static void
+_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));
+       exit (1);
+    }
+    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);
+           exit (1);
+       }
+       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));
+           exit (1);
+       }
+       addr->sin_port = servent->s_port;
+    }
+}
+
+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);
+    }
+}
+
+/* Exported: see ttt-socket.h for documentation. */
+int
+ttt_socket_create_server (const char *host, const char *port)
+{
+    int listen_socket;
+    struct sockaddr_in addr;
+
+    listen_socket = xsocket (PF_INET, SOCK_STREAM, 0);
+
+    _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);
+
+    return listen_socket;
+}
+
+/* Exported: see ttt-socket.h for documentation. */
+void
+ttt_socket_accept (int listen_socket, ttt_socket_dispatch_func_t dispatch)
+{
+    int connected_socket;
+
+    connected_socket = _wait_for_connection (listen_socket);
+
+    (dispatch) (connected_socket);
+}