Add support for holding an index instead of fieldname

src/expression.c

@@ -2,13 +2,20 @@
 
 #include "../lib/xalloc.h"
 
-node_t* alloc_node() 
+/* Static helper functions */
+
+static node_t* alloc_node();
+static int eval_single_node(node_t* node);
+
+static node_t* alloc_node() 
 {
 	node_t *node = xmalloc(sizeof(node_t));
 	memset(node, 0, sizeof(node_t));
 	return node;
 }
 
+/* Exposed functions */
+
 node_t* make_op_node(enum operation op) 
 {
 	node_t* node = alloc_node();
@@ -21,7 +28,7 @@ node_t* make_field_node(char *fieldname)
 {
 	node_t *node = alloc_node();
 	node->type = FIELD;
-	node->value.fieldname = fieldname;
+	node->value.field.fieldname = fieldname;
 	return node;
 }
 
@@ -56,7 +63,7 @@ void print_expression(node_t *root) {
 			printf(" %i ", root->value.op);
 			break;
 		case FIELD:
-			printf(" (%s", root->value.fieldname);
+			printf(" (%s", root->value.field.fieldname);
 			break;
 		case STRING:
 			printf("%s) ", root->value.string_literal);

src/expression.h

@@ -13,11 +13,16 @@ enum node_type {
 	OP, FIELD, STRING, INT
 };
 
-union node_value {
+struct field_id {
-	enum operation op;
+	int index;
 	char *fieldname;
+};
+
+union node_value {
+	struct field_id field; 
 	char *string_literal;
 	int int_literal;
+	enum operation op;
 };
 
 typedef struct node {
@@ -27,8 +32,6 @@ typedef struct node {
 	union node_value value;
 } node_t;
 
-node_t* alloc_node();
-
 node_t* make_op_node(enum operation op);
 
 node_t* make_field_node(char *fieldname);

src/filter.c

@@ -8,18 +8,19 @@ extern int yyparse();
 
 node_t *zfilter;
 
-void parse_filter_string(char *filter)
+int parse_filter_string(char *filter)
 {
 	YY_BUFFER_STATE buffer_state = yy_scan_string(filter);
 	int status = yyparse();
 	yy_delete_buffer(buffer_state);
 	if (status) {
 		// Error
-		log_fatal("zmap", "Unable to parse filter");
+		log_error("zmap", "Unable to parse filter string: '%s'", filter);
+		return 0;
 	}
 	zconf.filter.expression = zfilter;
 	print_expression(zfilter);
 	printf("%s\n", "");
 	fflush(stdout);
-	return;
+	return 1;
 }

src/filter.h

@@ -7,6 +7,6 @@ struct output_filter {
 	node_t *expression;
 };
 
-void parse_filter_string(char *filter);
+int parse_filter_string(char *filter);
 
 #endif /* ZMAP_FILTER_H */

src/zmap.c

@@ -501,7 +501,9 @@ int main(int argc, char *argv[])
 
 	// Parse and validate the output filter, if any
 	if (args.output_filter_arg) {
-		parse_filter_string(args.output_filter_arg);
+		if (!parse_filter_string(args.output_filter_arg)) {
+			log_fatal("zmap", "Unable to parse filter expression");
+		}
 	}
 
 	SET_BOOL(zconf.dryrun, dryrun);