discover/grub2: Improve error handling

Only run the script if the parse succeeded, and and improve the
error reporting by enabling verbose errors and line numbers.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

2 files changed, 6 insertions, 2 deletions

diff --git a/discover/grub2/lexer.l b/discover/grub2/lexer.l
index 3e1f9fa..6c0a456 100644
--- a/discover/grub2/lexer.l
+++ b/discover/grub2/lexer.l
@@ -12,6 +12,7 @@
 %option stack noyy_top_state
 %option reentrant
 %option bison-bridge
+%option yylineno
 %option noyyalloc noyyfree noyyrealloc
 %option extra-type="struct grub2_parser *"
 %option header-file="lexer.h"
diff --git a/discover/grub2/parser.y b/discover/grub2/parser.y
index e13cd72..550c374 100644
--- a/discover/grub2/parser.y
+++ b/discover/grub2/parser.y
@@ -2,6 +2,7 @@
 %pure-parser
 %lex-param { yyscan_t scanner }
 %parse-param { struct grub2_parser *parser }
+%error-verbose
 
 %{
 #include <talloc/talloc.h>
@@ -244,13 +245,15 @@ struct grub2_parser *grub2_parser_create(struct discover_context *ctx)
 void grub2_parser_parse(struct grub2_parser *parser, char *buf, int len)
 {
 	YY_BUFFER_STATE bufstate;
+	int rc;
 
 	bufstate = yy_scan_bytes(buf, len - 1, parser->scanner);
 
-	yyparse(parser);
+	rc = yyparse(parser);
 
 	yy_delete_buffer(bufstate, parser->scanner);
 
-	script_execute(parser->script);
+	if (!rc)
+		script_execute(parser->script);
 }