X forwarding changes:

- new function platform_get_x_display() to find a sensible local display.
   On Unix, the Gtk apps weren't taking account of --display when
   determining where to send forwarded X traffic.
 - explicitly document that leaving X display location blank in config tries
   to do something sensible (and that it's now blank by default)
 - don't override X11Display setting in plink, since that's more properly
   done later

[originally from svn r4604]

doc/config.but

@@ -1,4 +1,4 @@
-\versionid $Id: config.but,v 1.91 2004/10/02 00:33:27 jacob Exp $
+\versionid $Id: config.but,v 1.92 2004/10/06 22:31:07 jacob Exp $
 
 \C{config} Configuring PuTTY
 
@@ -2106,10 +2106,10 @@ forwarding allows you to securely give those applications access to
 a local X display on your PC.
 
 To enable X11 forwarding, check the \q{Enable X11 forwarding} box.
-If your X display is not the primary display on your local machine
-(which it almost certainly will be unless you have deliberately
-arranged otherwise), you need to enter its location in the \q{X
-display location} box.
+If your X display is somewhere unusual, you will need to enter its
+location in the \q{X display location} box; if this is left blank,
+PuTTY try to find a sensible default in the environment, or use the
+primary local display (\c{:0}) if that fails.
 
 See \k{using-x-forwarding} for more information about X11
 forwarding.

doc/using.but

@@ -1,4 +1,4 @@
-\versionid $Id: using.but,v 1.32 2004/09/22 22:15:25 jacob Exp $
+\versionid $Id: using.but,v 1.33 2004/10/06 22:31:07 jacob Exp $
 
 \C{using} Using PuTTY
 
@@ -304,9 +304,10 @@ does do.
 
 You should then tick the \q{Enable X11 forwarding} box in the
 Tunnels panel (see \k{config-ssh-x11}) before starting your SSH
-session. The \q{X display location} box reads \c{localhost:0} by
-default, which is the usual display location where your X server
-will be installed. If that needs changing, then change it.
+session. The \q{X display location} box is blank by default, which
+means that PuTTY will try to use a sensible default such as \c{:0},
+which is the usual display location where your X server will be
+installed. If that needs changing, then change it.
 
 Now you should be able to log in to the SSH server as normal. To
 check that X forwarding has been successfully negotiated during

ssh.h

@@ -298,6 +298,8 @@ extern const char platform_x11_best_transport[];
 /* best X11 hostname for this platform if none specified */
 SockAddr platform_get_x11_unix_address(int displaynum, char **canonicalname);
 /* make up a SockAddr naming the address for displaynum */
+char *platform_get_x_display(void);
+/* allocated local X display string, if any */
 
 Bignum copybn(Bignum b);
 Bignum bn_power_2(int n);

unix/ux_x11.c

@@ -119,5 +119,3 @@ void platform_get_x11_auth(char *display, int *protocol,
     pclose(fp);
     sfree(localbuf);
 }
-
-const char platform_x11_best_transport[] = "unix";

unix/uxcons.c

@@ -318,3 +318,13 @@ int is_interactive(void)
 {
     return isatty(0);
 }
+
+/*
+ * X11-forwarding-related things suitable for console.
+ */
+
+const char platform_x11_best_transport[] = "unix";
+
+char *platform_get_x_display(void) {
+    return dupstr(getenv("DISPLAY"));
+}

unix/uxplink.c

@@ -73,8 +73,6 @@ static Config cfg;
  */
 char *platform_default_s(const char *name)
 {
-    if (!strcmp(name, "X11Display"))
-	return dupstr(getenv("DISPLAY"));
     if (!strcmp(name, "TermType"))
 	return dupstr(getenv("TERM"));
     if (!strcmp(name, "UserName"))

unix/uxputty.c

@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <assert.h>
 #include <unistd.h>
+#include <gdk/gdk.h>
 
 #include "putty.h"
 #include "storage.h"
@@ -105,6 +106,21 @@ char *make_default_wintitle(char *hostname)
     return dupcat(hostname, " - PuTTY", NULL);
 }
 
+/*
+ * X11-forwarding-related things suitable for Gtk app.
+ */
+
+const char platform_x11_best_transport[] = "unix";
+
+char *platform_get_x_display(void) {
+    const char *display;
+    /* Try to take account of --display and what have you. */
+    if (!(display = gdk_get_display()))
+	/* fall back to traditional method */
+	display = getenv("DISPLAY");
+    return dupstr(display);
+}
+
 int main(int argc, char **argv)
 {
     extern int pt_main(int argc, char **argv);

unix/uxsftp.c

@@ -34,8 +34,6 @@ void platform_get_x11_auth(char *display, int *protocol,
     /* Do nothing, therefore no auth. */
 }
 
-const char platform_x11_best_transport[] = "unix";
-
 /*
  * Default settings that are specific to PSFTP.
  */

winmisc.c

@@ -16,6 +16,11 @@ void platform_get_x11_auth(char *display, int *proto,
 
 const char platform_x11_best_transport[] = "localhost";
 
+char *platform_get_x_display(void) {
+    /* We may as well check for DISPLAY in case it's useful. */
+    return dupstr(getenv("DISPLAY"));
+}
+
 Filename filename_from_str(const char *str)
 {
     Filename ret;

x11fwd.c

@@ -1,3 +1,7 @@
+/*
+ * Platform-independent bits of X11 forwarding.
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
@@ -228,14 +232,21 @@ int x11_get_screen_number(char *display)
 
 /* Find the right display, returns an allocated string */
 char *x11_display(const char *display) {
-    if(!display || !*display)
-	if(!(display = getenv("DISPLAY")))
-	    display = ":0";
-    if(display[0] == ':') {
-	/* no transport specified, use whatever we think is best */
-	return dupcat(platform_x11_best_transport, display, (char *)0);
+    char *ret;
+    if(!display || !*display) {
+	/* try to find platform-specific local display */
+	if(!(ret = platform_get_x_display()))
+	    /* plausible default for all platforms */
+	    ret = dupstr(":0");
     } else
-	return dupstr(display);
+	ret = dupstr(display);
+    if(ret[0] == ':') {
+	/* no transport specified, use whatever we think is best */
+	char *s = dupcat(platform_x11_best_transport, display, (char *)0);
+	sfree(ret);
+	return s;
+    } else
+	return ret;
 }
 
 /*