discover/grub2: Add function support

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

3 files changed, 57 insertions, 0 deletions

diff --git a/discover/grub2/grub2.h b/discover/grub2/grub2.h
index 4949f3c..5b83fad 100644
--- a/discover/grub2/grub2.h
+++ b/discover/grub2/grub2.h
@@ -71,6 +71,11 @@ struct grub2_statement_block {
 	struct grub2_statements	*statements;
 };
 
+struct grub2_statement_function {
+	struct grub2_statement	st;
+	struct grub2_word	*name;
+	struct grub2_statements	*body;
+};
 
 struct grub2_script {
 	struct grub2_statements		*statements;
@@ -105,6 +110,9 @@ struct grub2_statement *create_statement_if(struct grub2_parser *parser,
 struct grub2_statement *create_statement_block(struct grub2_parser *parser,
 		struct grub2_statements *stmts);
 
+struct grub2_statement *create_statement_function(struct grub2_parser *parser,
+		struct grub2_word *name, struct grub2_statements *body);
+
 struct grub2_word *create_word_text(struct grub2_parser *parser,
 		const char *text);
 
@@ -129,6 +137,8 @@ int statement_if_execute(struct grub2_script *script,
 		struct grub2_statement *statement);
 int statement_menuentry_execute(struct grub2_script *script,
 		struct grub2_statement *statement);
+int statement_function_execute(struct grub2_script *script,
+		struct grub2_statement *statement);
 
 struct grub2_script *create_script(struct grub2_parser *parser,
 		struct discover_context *ctx);
diff --git a/discover/grub2/parser.y b/discover/grub2/parser.y
index 550c374..bcf5935 100644
--- a/discover/grub2/parser.y
+++ b/discover/grub2/parser.y
@@ -95,6 +95,9 @@ statement: TOKEN_EOL {
 		"fi" TOKEN_EOL {
 		$$ = create_statement_if(parser, $3, $6, $9);
 	}
+	| "function" TOKEN_DELIM word TOKEN_DELIM '{' statements '}' {
+		$$ = create_statement_function(parser, $3, $6);
+	}
 	| "menuentry" TOKEN_DELIM words TOKEN_DELIM
 		'{' statements '}'
 		TOKEN_EOL {
@@ -181,6 +184,17 @@ struct grub2_statement *create_statement_block(struct grub2_parser *parser,
 	return &stmt->st;
 }
 
+struct grub2_statement *create_statement_function(struct grub2_parser *parser,
+		struct grub2_word *name, struct grub2_statements *body)
+{
+	struct grub2_statement_function *stmt =
+		talloc(parser, struct grub2_statement_function);
+	stmt->st.exec = statement_function_execute;
+	stmt->name = name;
+	stmt->body = body;
+	return &stmt->st;
+}
+
 void statement_append(struct grub2_statements *stmts,
 		struct grub2_statement *stmt)
 {
diff --git a/discover/grub2/script.c b/discover/grub2/script.c
index ec37fbb..9c08737 100644
--- a/discover/grub2/script.c
+++ b/discover/grub2/script.c
@@ -13,6 +13,8 @@
 	container_of(stmt, struct grub2_statement_if, st)
 #define to_stmt_menuentry(stmt) \
 	container_of(stmt, struct grub2_statement_menuentry, st)
+#define to_stmt_function(stmt) \
+	container_of(stmt, struct grub2_statement_function, st)
 
 struct env_entry {
 	const char		*name;
@@ -297,6 +299,37 @@ int statement_menuentry_execute(struct grub2_script *script,
 	return 0;
 }
 
+static int function_invoke(struct grub2_script *script,
+		void *data, int argc, char **argv)
+{
+	struct grub2_statement_function *fn = data;
+	char *name;
+	int i;
+
+	/* set positional parameters */
+	for (i = 0; i < argc; i++) {
+		name = talloc_asprintf(script, "$%d", i);
+		script_env_set(script, name, argv[i]);
+	}
+
+	return statements_execute(script, fn->body);
+}
+
+int statement_function_execute(struct grub2_script *script,
+		struct grub2_statement *statement)
+{
+	struct grub2_statement_function *st = to_stmt_function(statement);
+	const char *name;
+
+	if (st->name->type == GRUB2_WORD_VAR)
+		expand_var(script, st->name);
+
+	name = st->name->text;
+	script_register_function(script, name, function_invoke, st);
+
+	return 0;
+}
+
 static void init_env(struct grub2_script *script)
 {
 	struct env_entry *env;