discover/grub2: Add support for UUID and label for 'search' command

This change adds support for searching by UUID and filesystem label.
We still fall back to passthrough if the UUID is not found, but we now
resolve to device ID strings.

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

discover/grub2/builtins.c

@@ -115,27 +115,57 @@ static const struct option search_options[] = {
 		.has_arg = required_argument,
 		.val = 's',
 	},
+	{
+		.name = "file",
+		.has_arg = no_argument,
+		.val = 'f',
+	},
+	{
+		.name = "label",
+		.has_arg = no_argument,
+		.val = 'l',
+	},
+	{
+		.name = "fs-uuid",
+		.has_arg = no_argument,
+		.val = 'u',
+	},
 	{ 0 },
 };
 
 static int builtin_search(struct grub2_script *script,
 		void *data __attribute__((unused)),
 		int argc, char *argv[])
 {
-	const char *env_var, *spec;
+	const char *env_var, *spec, *res;
+	struct discover_device *dev;
+	enum {
+		LOOKUP_UUID = 'u',
+		LOOKUP_LABEL = 'l',
+		LOOKUP_FILE = 'f',
+	} lookup_type;
 
 	env_var = "root";
 	optind = 0;
 
+	/* Default to UUID, for backwards compat with earlier petitboot
+	 * versions. This argument is non-optional in GRUB. */
+	lookup_type = LOOKUP_UUID;
+
 	for (;;) {
-		int c = getopt_long(argc, argv, ":", search_options, NULL);
+		int c = getopt_long(argc, argv, ":flu", search_options, NULL);
 		if (c == -1)
 			break;
 
 		switch (c) {
 		case 's':
 			env_var = optarg;
 			break;
+		case LOOKUP_UUID:
+		case LOOKUP_LABEL:
+		case LOOKUP_FILE:
+			lookup_type = c;
+			break;
 		case '?':
 		case ':':
 			break;
@@ -149,8 +179,27 @@ static int builtin_search(struct grub2_script *script,
 		return -1;
 
 	spec = argv[optind];
+	res = NULL;
+
+	switch (lookup_type) {
+	case LOOKUP_UUID:
+		dev = device_lookup_by_uuid(script->ctx->handler,
+				spec);
+		res = dev ? dev->device->id : spec;
+		break;
+	case LOOKUP_LABEL:
+		dev = device_lookup_by_label(script->ctx->handler,
+				spec);
+		if (dev)
+			res = dev->device->id;
+		break;
+	case LOOKUP_FILE:
+		/* not yet implemented */
+		break;
+	}
 
-	script_env_set(script, env_var, spec);
+	if (res)
+		script_env_set(script, env_var, res);
 
 	return 0;
 }

test/parser/Makefile.am

@@ -30,6 +30,8 @@ parser_TESTS = \
 	test/parser/test-grub2-single-line-if \
 	test/parser/test-grub2-pos-param \
 	test/parser/test-grub2-search-args \
+	test/parser/test-grub2-search-uuid \
+	test/parser/test-grub2-search-label \
 	test/parser/test-grub2-load-env \
 	test/parser/test-grub2-save-env \
 	test/parser/test-grub2-save-env-dash-f \

test/parser/test-grub2-search-label.c

@@ -0,0 +1,47 @@
+/* check for grub2 search command, searching by partition label */
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+
+# valid label
+search --set=v1 --label testlabel
+
+v2=prev
+# invalid label: does not alter v2
+search --set=v2 --label invalidlabel
+
+menuentry $v1 {
+    linux /vmlinux
+}
+
+menuentry $v2 {
+    linux /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 = test_create_device(test, "testdev");
+	dev->label = "testlabel";
+	device_handler_add_device(test->handler, dev);
+
+	test_read_conf_embedded(test, "/grub/grub.cfg");
+
+	test_run_parser(test, "grub2");
+
+	check_boot_option_count(ctx, 2);
+
+	opt = get_boot_option(ctx, 0);
+	check_name(opt, "testdev");
+
+	opt = get_boot_option(ctx, 1);
+	check_name(opt, "prev");
+}

test/parser/test-grub2-search-uuid.c

@@ -0,0 +1,55 @@
+/* check for grub2 search command, searching by FS UUID */
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+
+# valid UUID
+search --set=v1 --fs-uuid ee0cc6fa-1dba-48f2-8f5b-19e4b8de8c37
+
+# invalid UUID: will fall back to passing the UUID through
+search --set=v2 --fs-uuid 92b0da57-6e04-4e54-960b-85e6bb060433
+
+# no 'type' argument defaults to UUID search
+search --set=v3 ee0cc6fa-1dba-48f2-8f5b-19e4b8de8c37
+
+menuentry $v1 {
+    linux /vmlinux
+}
+
+menuentry $v2 {
+    linux /vmlinux
+}
+
+menuentry $v3 {
+    linux /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 = test_create_device(test, "testdev");
+	dev->uuid = "ee0cc6fa-1dba-48f2-8f5b-19e4b8de8c37";
+	device_handler_add_device(test->handler, dev);
+
+	test_read_conf_embedded(test, "/grub/grub.cfg");
+
+	test_run_parser(test, "grub2");
+
+	check_boot_option_count(ctx, 3);
+
+	opt = get_boot_option(ctx, 0);
+	check_name(opt, dev->device->id);
+
+	opt = get_boot_option(ctx, 1);
+	check_name(opt, "92b0da57-6e04-4e54-960b-85e6bb060433");
+
+	opt = get_boot_option(ctx, 2);
+	check_name(opt, dev->device->id);
+}