}
 
 sub trusterror {
-       die shift()."\n".
-               "(To trust this file, list it in ~/.mrtrust.)\n";
+       my ($err, $file, $line, $url)=@_;
+       
+       if (defined $url) {
+               die "$err in untrusted $url line $line\n".
+                       "(To trust this url, --trust-all can be used; but please use caution;\n".
+                       "this can allow arbitrary code execution!)\n";
+       }
+       else {
+               die "$err in untrusted $file line $line\n".
+                       "(To trust this file, list it in ~/.mrtrust.)\n";
+       }
 }
 
 my %loaded;
 sub loadconfig {
        my $f=shift;
        my $dir=shift;
+       my $bootstrap_url=shift;
 
        my @toload;
 
                $trusted=1;
        }
        else {
-               if (! -e $f) {
-                       return;
-               }
-
                my $absf=abs_path($f);
                if ($loaded{$absf}) {
                        return;
                        }
                }
                
+               if (! -e $f) {
+                       return;
+               }
+
                print "mr: loading config $f\n" if $verbose;
                open($in, "<", $f) || die "mr: open $f: $!\n";
        }
                                if (! is_trusted_repo($section) ||
                                    $section eq 'ALIAS' ||
                                    $section eq 'DEFAULT') {
-                                       trusterror "mr: illegal section \"[$section]\" in untrusted $f line $line";
+                                       trusterror("mr: illegal section \"[$section]\"", $f, $line, $bootstrap_url)
                                }
                        }
                        $section=expandenv($section) if $trusted;
                                # Untrusted files can only contain checkout
                                # parameters.
                                if ($parameter ne 'checkout') {
-                                       trusterror "mr: illegal setting \"$parameter=$value\" in untrusted $f line $line";
+                                       trusterror("mr: illegal setting \"$parameter=$value\"", $f, $line, $bootstrap_url);
                                }
                                if (! is_trusted_checkout($value)) {
-                                       trusterror "mr: illegal checkout command \"$value\" in untrusted $f line $line";
+                                       trusterror("mr: illegal checkout command \"$value\"", $f, $line, $bootstrap_url);
                                }
                        }
 
        # would normally be skipped.
        my $topdir=abs_path(".")."/";
        my @repo=($topdir, $topdir, ".");
-       loadconfig($tmpconfig, $topdir);
+       loadconfig($tmpconfig, $topdir, $url);
        record(\@repo, action("checkout", @repo, 1))
                if exists $config{$topdir}{"."}{"checkout"};