sub generate_traceevent_regex()

in trace/postprocess/trace-vmscan-postprocess.pl [137:182]

• 37 lines of code
• 7 McCabe index (conditional complexity)

sub generate_traceevent_regex {
	my $event = shift;
	my $default = shift;
	my $regex;

	# Read the event format or use the default
	if (!open (FORMAT, "/sys/kernel/debug/tracing/events/$event/format")) {
		print("WARNING: Event $event format string not found\n");
		return $default;
	} else {
		my $line;
		while (!eof(FORMAT)) {
			$line = <FORMAT>;
			$line =~ s/, REC->.*//;
			if ($line =~ /^print fmt:\s"(.*)".*/) {
				$regex = $1;
				$regex =~ s/%s/\([0-9a-zA-Z|_]*\)/g;
				$regex =~ s/%p/\([0-9a-f]*\)/g;
				$regex =~ s/%d/\([-0-9]*\)/g;
				$regex =~ s/%ld/\([-0-9]*\)/g;
				$regex =~ s/%lu/\([0-9]*\)/g;
			}
		}
	}

	# Can't handle the print_flags stuff but in the context of this
	# script, it really doesn't matter
	$regex =~ s/\(REC.*\) \? __print_flags.*//;

	# Verify fields are in the right order
	my $tuple;
	foreach $tuple (split /\s/, $regex) {
		my ($key, $value) = split(/=/, $tuple);
		my $expected = shift;
		if ($key ne $expected) {
			print("WARNING: Format not as expected for event $event '$key' != '$expected'\n");
			$regex =~ s/$key=\((.*)\)/$key=$1/;
		}
	}

	if (defined shift) {
		die("Fewer fields than expected in format");
	}

	return $regex;
}