commands: boot: refactor boot entry creation to use iterators

We currently create all boot entries before attempting boot. This is
less than optimal, because this may involve probing devices that won't
be used for actual boot.

In preparation for changing this, refactor the code, so we only have one
loop we need to touch.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 28 insertions, 16 deletions

diff --git a/commands/boot.c b/commands/boot.c
index 0257b3dd4f..ce4eeac653 100644
--- a/commands/boot.c
+++ b/commands/boot.c
@@ -21,13 +21,29 @@
 
 #include <linux/stat.h>
 
+static char *next_argv(void *context)
+{
+	char ***argv = context;
+	char *next = **argv;
+	(*argv)++;
+	return next;
+}
+
+static char *next_word(void *context)
+{
+	return strsep(context, " ");
+}
+
 static int do_boot(int argc, char *argv[])
 {
 	char *freep = NULL;
 	int opt, ret = 0, do_list = 0, do_menu = 0;
-	int i, dryrun = 0, verbose = 0, timeout = -1;
+	int dryrun = 0, verbose = 0, timeout = -1;
 	struct bootentries *entries;
 	struct bootentry *entry;
+	void *handle;
+	const char *name;
+	char *(*next)(void *);
 
 	while ((opt = getopt(argc, argv, "vldmt:w:")) > 0) {
 		switch (opt) {
@@ -54,31 +70,26 @@ static int do_boot(int argc, char *argv[])
 		}
 	}
 
-	entries = bootentries_alloc();
-
 	if (optind < argc) {
-		for (i = optind; i < argc; i++) {
-			ret = bootentry_create_from_name(entries, argv[i]);
-			if (ret <= 0)
-				printf("Nothing bootable found on '%s'\n", argv[i]);
-	       }
+		handle = &argv[optind];
+		next = next_argv;
 	} else {
 		const char *def;
-		char *sep, *name;
 
 		def = getenv("global.boot.default");
 		if (!def)
 			return 0;
 
-		sep = freep = xstrdup(def);
+		handle = freep = xstrdup(def);
+		next = next_word;
+	}
 
-		while ((name = strsep(&sep, " ")) != NULL) {
-			ret = bootentry_create_from_name(entries, name);
-			if (ret <= 0)
-				printf("Nothing bootable found on '%s'\n", name);
-		}
+	entries = bootentries_alloc();
 
-		free(freep);
+	while ((name = next(&handle)) != NULL) {
+		ret = bootentry_create_from_name(entries, name);
+		if (ret <= 0)
+			printf("Nothing bootable found on '%s'\n", name);
 	}
 
 	if (list_empty(&entries->entries)) {
@@ -104,6 +115,7 @@ static int do_boot(int argc, char *argv[])
 
 out:
 	bootentries_free(entries);
+	free(freep);
 
 	return ret;
 }