The `socket' function in the backends is only ever checked to see if

it's NULL. Since we already have one back end (uxpty) which doesn't
in fact talk to a network socket, and may well have more soon, I'm
replacing this TCP/IP-centric function with a nice neutral
`connected' function returning a boolean. Nothing else about its
semantics has currently changed.

[originally from svn r6810]

pscp.c

@@ -292,7 +292,7 @@ static void bump(char *fmt, ...)
     sfree(str2);
     errs++;
 
-    if (back != NULL && back->socket(backhandle) != NULL) {
+    if (back != NULL && back->connected(backhandle)) {
 	char ch;
 	back->special(backhandle, TS_EOF);
 	ssh_scp_recv((unsigned char *) &ch, 1);
@@ -2285,7 +2285,7 @@ int psftp_main(int argc, char *argv[])
 	    tolocal(argc, argv);
     }
 
-    if (back != NULL && back->socket(backhandle) != NULL) {
+    if (back != NULL && back->connected(backhandle)) {
 	char ch;
 	back->special(backhandle, TS_EOF);
 	ssh_scp_recv((unsigned char *) &ch, 1);

psftp.c

@@ -952,7 +952,7 @@ int sftp_cmd_close(struct sftp_command *cmd)
 	return 0;
     }
 
-    if (back != NULL && back->socket(backhandle) != NULL) {
+    if (back != NULL && back->connected(backhandle)) {
 	char ch;
 	back->special(backhandle, TS_EOF);
 	sftp_recvdata(&ch, 1);
@@ -2909,7 +2909,7 @@ int psftp_main(int argc, char *argv[])
 
     do_sftp(mode, modeflags, batchfile);
 
-    if (back != NULL && back->socket(backhandle) != NULL) {
+    if (back != NULL && back->connected(backhandle)) {
 	char ch;
 	back->special(backhandle, TS_EOF);
 	sftp_recvdata(&ch, 1);

putty.h

@@ -357,7 +357,7 @@ struct backend_tag {
     void (*size) (void *handle, int width, int height);
     void (*special) (void *handle, Telnet_Special code);
     const struct telnet_special *(*get_specials) (void *handle);
-    Socket(*socket) (void *handle);
+    int (*connected) (void *handle);
     int (*exitcode) (void *handle);
     /* If back->sendok() returns FALSE, data sent to it from the frontend
      * may be lost. */

raw.c

@@ -209,10 +209,10 @@ static const struct telnet_special *raw_get_specials(void *handle)
     return NULL;
 }
 
-static Socket raw_socket(void *handle)
+static int raw_connected(void *handle)
 {
     Raw raw = (Raw) handle;
-    return raw->s;
+    return raw->s != NULL;
 }
 
 static int raw_sendok(void *handle)
@@ -270,7 +270,7 @@ Backend raw_backend = {
     raw_size,
     raw_special,
     raw_get_specials,
-    raw_socket,
+    raw_connected,
     raw_exitcode,
     raw_sendok,
     raw_ldisc,

rlogin.c

@@ -280,10 +280,10 @@ static const struct telnet_special *rlogin_get_specials(void *handle)
     return NULL;
 }
 
-static Socket rlogin_socket(void *handle)
+static int rlogin_connected(void *handle)
 {
     Rlogin rlogin = (Rlogin) handle;
-    return rlogin->s;
+    return rlogin->s != NULL;
 }
 
 static int rlogin_sendok(void *handle)
@@ -341,7 +341,7 @@ Backend rlogin_backend = {
     rlogin_size,
     rlogin_special,
     rlogin_get_specials,
-    rlogin_socket,
+    rlogin_connected,
     rlogin_exitcode,
     rlogin_sendok,
     rlogin_ldisc,

ssh.c

@@ -8725,10 +8725,10 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
     }
 }
 
-static Socket ssh_socket(void *handle)
+static int ssh_connected(void *handle)
 {
     Ssh ssh = (Ssh) handle;
-    return ssh->s;
+    return ssh->s != NULL;
 }
 
 static int ssh_sendok(void *handle)
@@ -8798,7 +8798,7 @@ Backend ssh_backend = {
     ssh_size,
     ssh_special,
     ssh_get_specials,
-    ssh_socket,
+    ssh_connected,
     ssh_return_exitcode,
     ssh_sendok,
     ssh_ldisc,

telnet.c

@@ -1019,10 +1019,10 @@ static const struct telnet_special *telnet_get_specials(void *handle)
     return specials;
 }
 
-static Socket telnet_socket(void *handle)
+static int telnet_connected(void *handle)
 {
     Telnet telnet = (Telnet) handle;
-    return telnet->s;
+    return telnet->s != NULL;
 }
 
 static int telnet_sendok(void *handle)
@@ -1085,7 +1085,7 @@ Backend telnet_backend = {
     telnet_size,
     telnet_special,
     telnet_get_specials,
-    telnet_socket,
+    telnet_connected,
     telnet_exitcode,
     telnet_sendok,
     telnet_ldisc,

unix/uxplink.c

@@ -899,7 +899,7 @@ int main(int argc, char **argv)
 	FD_SET_MAX(signalpipe[0], maxfd, rset);
 
 	if (connopen && !sending &&
-	    back->socket(backhandle) != NULL &&
+	    back->connected(backhandle) &&
 	    back->sendok(backhandle) &&
 	    back->sendbuffer(backhandle) < MAX_STDIN_BACKLOG) {
 	    /* If we're OK to send, then try to read from stdin. */
@@ -1014,7 +1014,7 @@ int main(int argc, char **argv)
 	    char buf[4096];
 	    int ret;
 
-	    if (connopen && back->socket(backhandle) != NULL) {
+	    if (connopen && back->connected(backhandle)) {
 		ret = read(0, buf, sizeof(buf));
 		if (ret < 0) {
 		    perror("stdin: read");
@@ -1039,7 +1039,7 @@ int main(int argc, char **argv)
 	    try_output(1);
 	}
 
-	if ((!connopen || back->socket(backhandle) == NULL) &&
+	if ((!connopen || !back->connected(backhandle)) &&
 	    bufchain_size(&stdout_data) == 0 &&
 	    bufchain_size(&stderr_data) == 0)
 	    break;		       /* we closed the connection */

unix/uxpty.c

@@ -1008,10 +1008,10 @@ static const struct telnet_special *pty_get_specials(void *handle)
     return NULL;
 }
 
-static Socket pty_socket(void *handle)
+static int pty_connected(void *handle)
 {
     /* Pty pty = (Pty)handle; */
-    return NULL;		       /* shouldn't ever be needed */
+    return TRUE;
 }
 
 static int pty_sendok(void *handle)
@@ -1068,7 +1068,7 @@ Backend pty_backend = {
     pty_size,
     pty_special,
     pty_get_specials,
-    pty_socket,
+    pty_connected,
     pty_exitcode,
     pty_sendok,
     pty_ldisc,

windows/winplink.c

@@ -218,7 +218,7 @@ int stdin_gotdata(struct handle *h, void *data, int len)
 	cleanup_exit(0);
     }
     noise_ultralight(len);
-    if (connopen && back->socket(backhandle) != NULL) {
+    if (connopen && back->connected(backhandle)) {
 	if (len > 0) {
 	    return back->send(backhandle, data, len);
 	} else {
@@ -239,7 +239,7 @@ void stdouterr_sent(struct handle *h, int new_backlog)
 		(h == stdout_handle ? "output" : "error"));
 	cleanup_exit(0);
     }
-    if (connopen && back->socket(backhandle) != NULL) {
+    if (connopen && back->connected(backhandle)) {
 	back->unthrottle(backhandle, (handle_backlog(stdout_handle) +
 				      handle_backlog(stderr_handle)));
     }
@@ -694,7 +694,7 @@ int main(int argc, char **argv)
 	if (sending)
 	    handle_unthrottle(stdin_handle, back->sendbuffer(backhandle));
 
-	if ((!connopen || back->socket(backhandle) == NULL) &&
+	if ((!connopen || !back->connected(backhandle)) &&
 	    handle_backlog(stdout_handle) + handle_backlog(stderr_handle) == 0)
 	    break;		       /* we closed the connection */
     }