discover/grub2: Use getopt for search argument parsing

The search command will be extended to add the full set of grub2-style
arguments, so switch to using getopt, rather than manual parsing.

This means we now support `--set=foo` and `--set foo` style arguments,
both of which appear in the docs and common grub configs.

Also, add a small test for the search argument handling.

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

discover/grub2/builtins.c

@@ -1,4 +1,7 @@
 
+#define _GNU_SOURCE
+
+#include <getopt.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -106,26 +109,46 @@ static int builtin_initrd(struct grub2_script *script,
 	return 0;
 }
 
+static const struct option search_options[] = {
+	{
+		.name = "set",
+		.has_arg = required_argument,
+		.val = 's',
+	},
+	{ 0 },
+};
+
 static int builtin_search(struct grub2_script *script,
 		void *data __attribute__((unused)),
 		int argc, char *argv[])
 {
 	const char *env_var, *spec;
-	int i;
 
 	env_var = "root";
+	optind = 0;
+
+	for (;;) {
+		int c = getopt_long(argc, argv, ":", search_options, NULL);
+		if (c == -1)
+			break;
 
-	for (i = 1; i < argc - 1; i++) {
-		if (!strncmp(argv[i], "--set=", strlen("--set="))) {
-			env_var = argv[i] + strlen("--set=");
+		switch (c) {
+		case 's':
+			env_var = optarg;
+			break;
+		case '?':
+		case ':':
 			break;
 		}
 	}
 
 	if (!strlen(env_var))
 		return 0;
 
-	spec = argv[argc - 1];
+	if (optind >= argc)
+		return -1;
+
+	spec = argv[optind];
 
 	script_env_set(script, env_var, spec);
 

test/parser/Makefile.am

@@ -29,6 +29,7 @@ parser_TESTS = \
 	test/parser/test-grub2-multiple-id \
 	test/parser/test-grub2-single-line-if \
 	test/parser/test-grub2-pos-param \
+	test/parser/test-grub2-search-args \
 	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-args.c

@@ -0,0 +1,33 @@
+
+/* check for multiple styles of option parsing for the 'search' command */
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+
+# no --set arugment will set the 'root' var
+search a
+search --set=v1 b
+search --set v2 c
+
+menuentry $root$v1$v2 {
+    linux /vmlinux
+}
+
+#endif
+
+void run_test(struct parser_test *test)
+{
+	struct discover_boot_option *opt;
+	struct discover_context *ctx;
+
+	ctx = test->ctx;
+
+	test_read_conf_embedded(test, "/grub/grub.cfg");
+
+	test_run_parser(test, "grub2");
+
+	check_boot_option_count(ctx, 1);
+	opt = get_boot_option(ctx, 0);
+	check_name(opt, "abc");
+}