discover/grub2: Add support for for-loops

GRUB2 syntax allows for for-loops; this change adds supoprt in the
parser grammar and script execution code to implement them. In the
execution code, we simply update the for-loop variable and re-execute
the body statements.

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

1 files changed, 23 insertions, 0 deletions

diff --git a/discover/grub2/script.c b/discover/grub2/script.c
index bfca607..0618297 100644
--- a/discover/grub2/script.c
+++ b/discover/grub2/script.c
@@ -19,6 +19,8 @@
 	container_of(stmt, struct grub2_statement_menuentry, st)
 #define to_stmt_function(stmt) \
 	container_of(stmt, struct grub2_statement_function, st)
+#define to_stmt_for(stmt) \
+	container_of(stmt, struct grub2_statement_for, st)
 #define to_stmt_conditional(stmt) \
 	container_of(stmt, struct grub2_statement_conditional, st)
 
@@ -401,6 +403,27 @@ int statement_function_execute(struct grub2_script *script,
 	return 0;
 }
 
+int statement_for_execute(struct grub2_script *script,
+		struct grub2_statement *statement)
+{
+	struct grub2_statement_for *st = to_stmt_for(statement);
+	const char *varname;
+	int i, rc = 0;
+
+	if (st->var->type == GRUB2_WORD_VAR)
+		expand_var(script, st->var);
+	varname = st->var->text;
+
+	process_expansions(script, st->list);
+
+	for (i = 0; i < st->list->argc; ++i) {
+		script_env_set(script, varname, st->list->argv[i]);
+		rc = statements_execute(script, st->body);
+	}
+
+	return rc;
+}
+
 static void init_env(struct grub2_script *script)
 {
 	struct env_entry *env;