ktest: Add OVERRIDE keyword to DEFAULTS section

The OVERRIDE keyword will allow options defined in the given
DEFAULTS section to override options defined in previous DEFAULT
sections.

Normally, options will error if they were previous defined.
The OVERRIDE keyword allows options that have been previously
defined to be changed in the given section.

Note, the same option can not be defined in the same DEFAULT section
even if that section is marked as OVERRIDE.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

tools/testing/ktest/ktest.pl

@@ -337,10 +337,17 @@ sub process_variables {
 }
 
 sub set_value {
-    my ($lvalue, $rvalue) = @_;
+    my ($lvalue, $rvalue, $override, $overrides, $name) = @_;
 
     if (defined($opt{$lvalue})) {
-	die "Error: Option $lvalue defined more than once!\n";
+	if (!$override || defined(${$overrides}{$lvalue})) {
+	    my $extra = "";
+	    if ($override) {
+		$extra = "In the same override section!\n";
+	    }
+	    die "$name: $.: Option $lvalue defined more than once!\n$extra";
+	}
+	${$overrides}{$lvalue} = $rvalue;
     }
     if ($rvalue =~ /^\s*$/) {
 	delete $opt{$lvalue};
@@ -430,6 +437,9 @@ sub __read_config {
     my $test_case = 0;
     my $if = 0;
     my $if_set = 0;
+    my $override = 0;
+
+    my %overrides;
 
     while (<$in>) {
 
@@ -443,6 +453,7 @@ sub __read_config {
 
 	    my $old_test_num;
 	    my $old_repeat;
+	    $override = 0;
 
 	    if ($type eq "TEST_START") {
 
@@ -468,10 +479,20 @@ sub __read_config {
 		$skip = 0;
 	    }
 
-	    if ($rest =~ /\s+ITERATE\s+(\d+)(.*)$/) {
-		$repeat = $1;
-		$rest = $2;
-		$repeat_tests{"$test_num"} = $repeat;
+	    if (!$skip) {
+		if ($type eq "TEST_START") {
+		    if ($rest =~ /\s+ITERATE\s+(\d+)(.*)$/) {
+			$repeat = $1;
+			$rest = $2;
+			$repeat_tests{"$test_num"} = $repeat;
+		    }
+		} elsif ($rest =~ /\sOVERRIDE\b(.*)/) {
+		    # DEFAULT only
+		    $rest = $1;
+		    $override = 1;
+		    # Clear previous overrides
+		    %overrides = ();
+		}
 	    }
 
 	    if ($rest =~ /\sIF\s+(.*)/) {
@@ -573,10 +594,10 @@ sub __read_config {
 	    }
 
 	    if ($default || $lvalue =~ /\[\d+\]$/) {
-		set_value($lvalue, $rvalue);
+		set_value($lvalue, $rvalue, $override, \%overrides, $name);
 	    } else {
 		my $val = "$lvalue\[$test_num\]";
-		set_value($val, $rvalue);
+		set_value($val, $rvalue, $override, \%overrides, $name);
 
 		if ($repeat > 1) {
 		    $repeats{$val} = $repeat;

tools/testing/ktest/sample.conf

@@ -72,6 +72,21 @@
 # the same option name under the same test or as default
 # ktest will fail to execute, and no tests will run.
 #
+# DEFAULTS OVERRIDE
+#
+# Options defined in the DEFAULTS section can not be duplicated
+# even if they are defined in two different DEFAULT sections.
+# This is done to catch mistakes where an option is added but
+# the previous option was forgotten about and not commented.
+#
+# The OVERRIDE keyword can be added to a section to allow this
+# section to override other DEFAULT sections values that have
+# been defined previously. It will only override options that
+# have been defined before its use. Options defined later
+# in a non override section will still error. The same option
+# can not be defined in the same section even if that section
+# is marked OVERRIDE.
+#
 #
 #
 # Both TEST_START and DEFAULTS sections can also have the IF keyword