+2005-11-09 Carl Worth <cworth@cworth.org>
+
+ * src/Makefile.am:
+ * src/ttt.h:
+ * src/ttt-server.c: (ttt_dispatch), (main):
+ * src/ttt-socket.h:
+ * src/ttt-socket.c: (_sockaddr_init), (_wait_for_connection),
+ (ttt_socket_create_server), (ttt_socket_accept): Push a lot of
+ code out of ttt-server.c down into a new ttt_socket abstraction
+ layer. The code is much easier to read now. The server also no
+ longer exits when the first client exits, but continues to listen
+ for more connections.
+
2005-11-09 Carl Worth <cworth@cworth.org>
* src/ttt-args.h:
ttt-args.h \
ttt-board.c \
ttt-board.h \
+ ttt-socket.c \
+ ttt-socket.h \
x.c \
x.h
*/
#include "ttt.h"
+#include "ttt-socket.h"
-static ttt_status_t
-_sockaddr_init (struct sockaddr_in *addr,
- const char *host,
- const char *port)
+static void
+ttt_dispatch (int connected_socket)
{
- 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);
+#define BUF_SIZE 1024
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);
+ 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);
}
}
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"
+"of a TCP/IP server that handles one client at a time. The server is\n"
+"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"
"<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";
+"\nPS. The server handles only one client at a time, but multiple clients\n"
+"may be able to connect simultaneously. Subsequent clients will see no\n"
+"output from the server until all previous clients exit.\n"
+"\nExtending the server to fork a new process for each client would be a fun\n"
+"project for a motivated student (as would writing a custom client program).\n\n";
int
main (int argc, char **argv)
{
ttt_args_t args;
- int listen_socket, connected_socket;
- struct sockaddr_in addr;
+ int socket;
ttt_args_parse (&args, argc, argv);
if (args.log_file)
stderr = xfreopen (args.log_file, "a", stderr);
- listen_socket = xsocket (PF_INET, SOCK_STREAM, 0);
-
- _sockaddr_init (&addr, args.host, args.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);
+ socket = ttt_socket_create_server (args.host, args.port);
printf (WELCOME_MESSAGE, args.host, args.port, args.host, args.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);
- }
+ while (1)
+ ttt_socket_accept (socket, ttt_dispatch);
- return 0;
+ /* We only reach here if something bad happened. */
+ return 1;
}
--- /dev/null
+/* 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);
+}
--- /dev/null
+/* 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>
+ */
+
+#ifndef _TTT_SOCKET_H_
+#define _TTT_SOCKET_H_
+
+#include "ttt.h"
+
+typedef void (*ttt_socket_dispatch_func_t) (int connected_socket);
+
+/* Create a socket, bind it to the given host and port, and listen in
+ * preparation for incoming connections. See ttt_socket_accept for a
+ * way to actually accept those incoming connections.
+ *
+ * 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.
+ *
+ * Return value: The created socket as a file descriptor.
+ *
+ * Errors: If any error occurs, this function will not return.
+ */
+int
+ttt_socket_create_server (const char *host, const char *port);
+
+/* Wait for an incoming connection on listen_socket, (which should be
+ * a valid socket on which bind and listen have already been
+ * called---see ttt_socket_create_server), then call the dispatch
+ * function with the new socket from the connection.
+ */
+void
+ttt_socket_accept (int listen_socket, ttt_socket_dispatch_func_t dispatch);
+
+#endif
#include <ctype.h>
#include <sys/types.h>
#include <sys/socket.h>
-#include <netinet/ip.h>
-#include <netdb.h>
#define ASSERT_NOT_REACHED \
do { \
projects / ttt / commitdiff