discover/grub2: implement 'source' command

This change add support for the grub2 'source' command, executing a
referenced script in the current parse context.

We impose a limit of 10 (concurrent) source commands, to prevent
infinite recursion.

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

discover/grub2/builtins.c

@@ -401,6 +401,51 @@ static int builtin_test(struct grub2_script *script,
 	return rc ? 0 : 1;
 }
 
+static int builtin_source(struct grub2_script *script,
+		void *data __attribute__((unused)),
+		int argc, char *argv[])
+{
+	struct grub2_statements *statements;
+	struct discover_device *dev;
+	const char *filename;
+	char *path, *buf;
+	int rc, len;
+
+	if (argc != 2)
+		return false;
+
+	/* limit script recursion */
+	if (script->include_depth >= 10)
+		return false;
+
+	rc = parse_to_device_path(script, argv[1], &dev, &path);
+	if (rc)
+		return false;
+
+	rc = parser_request_file(script->ctx, dev, path, &buf, &len);
+	if (rc)
+		return false;
+
+	/* save current script state */
+	statements = script->statements;
+	filename = script->filename;
+	script->include_depth++;
+
+	rc = grub2_parser_parse(script->parser, argv[1], buf, len);
+
+	if (!rc)
+		statements_execute(script, script->statements);
+
+	talloc_free(script->statements);
+
+	/* restore state */
+	script->statements = statements;
+	script->filename = filename;
+	script->include_depth--;
+
+	return !rc;
+}
+
 static int builtin_true(struct grub2_script *script __attribute__((unused)),
 		void *data __attribute__((unused)),
 		int argc __attribute__((unused)),
@@ -491,7 +536,11 @@ static struct {
 	{
 		.name = "blscfg",
 		.fn = builtin_blscfg,
-	}
+	},
+	{
+		.name = "source",
+		.fn = builtin_source,
+	},
 };
 
 static const char *nops[] = {

discover/grub2/grub2.h

@@ -100,6 +100,7 @@ struct grub2_script {
 	const char			*filename;
 	unsigned int			n_options;
 	struct list			options;
+	int				include_depth;
 };
 
 struct grub2_parser {

test/parser/Makefile.am

@@ -46,6 +46,10 @@ parser_TESTS = \
 	test/parser/test-grub2-lexer-error \
 	test/parser/test-grub2-parser-error \
 	test/parser/test-grub2-test-file-ops \
+	test/parser/test-grub2-source \
+	test/parser/test-grub2-source-functions \
+	test/parser/test-grub2-source-recursion \
+	test/parser/test-grub2-source-recursion-infinite \
 	test/parser/test-grub2-single-yocto \
 	test/parser/test-grub2-blscfg-default-filename \
 	test/parser/test-grub2-blscfg-default-index \

test/parser/test-grub2-source-functions.c

@@ -0,0 +1,46 @@
+
+/* check that we can source other scripts, and functions can be defined
+ * and called across sourced scripts */
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+
+function f1 {
+	menuentry "f1$1" { linux $2 }
+}
+
+source /grub/2.cfg
+
+f2 a /vmlinux
+
+#endif
+
+void run_test(struct parser_test *test)
+{
+	struct discover_boot_option *opt;
+	struct discover_context *ctx;
+	struct discover_device *dev;
+
+	ctx = test->ctx;
+	dev = ctx->device;
+
+	test_read_conf_embedded(test, "/grub/grub.cfg");
+
+	test_add_file_string(test, dev,
+			"/grub/2.cfg",
+			"function f2 { menuentry \"f2$1\" { linux $2 } }\n"
+			"f1 a /vmlinux\n");
+
+	test_run_parser(test, "grub2");
+
+	check_boot_option_count(ctx, 2);
+
+	opt = get_boot_option(ctx, 0);
+	check_name(opt, "f1a");
+	check_resolved_local_resource(opt->boot_image, dev, "/vmlinux");
+
+	opt = get_boot_option(ctx, 1);
+	check_name(opt, "f2a");
+	check_resolved_local_resource(opt->boot_image, dev, "/vmlinux");
+}

test/parser/test-grub2-source-recursion-infinite.c

@@ -0,0 +1,43 @@
+
+/* check that have a maximum source recursion limit */
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+
+name=a$name
+
+menuentry $name {
+	linux /a
+}
+
+source /grub/grub.cfg
+
+#endif
+
+void run_test(struct parser_test *test)
+{
+	struct discover_boot_option *opt;
+	struct discover_context *ctx;
+	struct discover_device *dev;
+
+	ctx = test->ctx;
+	dev = ctx->device;
+
+	test_read_conf_embedded(test, "/grub/grub.cfg");
+
+	test_run_parser(test, "grub2");
+
+	/* we error out after 10 levels, but we should still have
+	 * parse results up to that point
+	 */
+	check_boot_option_count(ctx, 11);
+
+	opt = get_boot_option(ctx, 0);
+	check_name(opt, "a");
+	check_resolved_local_resource(opt->boot_image, dev, "/a");
+
+	opt = get_boot_option(ctx,10);
+	check_name(opt, "aaaaaaaaaaa");
+	check_resolved_local_resource(opt->boot_image, dev, "/a");
+}

test/parser/test-grub2-source-recursion.c

@@ -0,0 +1,58 @@
+/* check that we can source other files recursively */
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+
+menuentry a {
+	linux /a
+}
+
+source /grub/2.cfg
+
+menuentry c {
+	linux /c
+}
+
+#endif
+
+void run_test(struct parser_test *test)
+{
+	struct discover_boot_option *opt;
+	struct discover_context *ctx;
+	struct discover_device *dev;
+
+	ctx = test->ctx;
+	dev = ctx->device;
+
+	test_read_conf_embedded(test, "/grub/grub.cfg");
+
+	/* four levels of config files, the last defining a boot option */
+	test_add_file_string(test, dev,
+			"/grub/2.cfg",
+			"source /grub/3.cfg\n");
+
+	test_add_file_string(test, dev,
+			"/grub/3.cfg",
+			"source /grub/4.cfg\n");
+
+	test_add_file_string(test, dev,
+			"/grub/4.cfg",
+			"menuentry b { linux /b }\n");
+
+	test_run_parser(test, "grub2");
+
+	check_boot_option_count(ctx, 3);
+
+	opt = get_boot_option(ctx, 0);
+	check_name(opt, "a");
+	check_resolved_local_resource(opt->boot_image, dev, "/a");
+
+	opt = get_boot_option(ctx, 1);
+	check_name(opt, "b");
+	check_resolved_local_resource(opt->boot_image, dev, "/b");
+
+	opt = get_boot_option(ctx, 2);
+	check_name(opt, "c");
+	check_resolved_local_resource(opt->boot_image, dev, "/c");
+}

test/parser/test-grub2-source.c

@@ -0,0 +1,54 @@
+
+/* check that we can source other scripts, and variables get passed
+ * in to and out of sourced scripts */
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+
+menuentry a {
+	linux /a
+}
+
+# var: outer -> inner -> outer
+v=b
+
+source /grub/2.cfg
+
+menuentry $v {
+	linux /c
+}
+
+#endif
+
+void run_test(struct parser_test *test)
+{
+	struct discover_boot_option *opt;
+	struct discover_context *ctx;
+	struct discover_device *dev;
+
+	ctx = test->ctx;
+	dev = ctx->device;
+
+	test_read_conf_embedded(test, "/grub/grub.cfg");
+
+	test_add_file_string(test, dev,
+			"/grub/2.cfg",
+			"menuentry $v { linux /b }\nv=c\n");
+
+	test_run_parser(test, "grub2");
+
+	check_boot_option_count(ctx, 3);
+
+	opt = get_boot_option(ctx, 0);
+	check_name(opt, "a");
+	check_resolved_local_resource(opt->boot_image, dev, "/a");
+
+	opt = get_boot_option(ctx, 1);
+	check_name(opt, "b");
+	check_resolved_local_resource(opt->boot_image, dev, "/b");
+
+	opt = get_boot_option(ctx, 2);
+	check_name(opt, "c");
+	check_resolved_local_resource(opt->boot_image, dev, "/c");
+}