boot: pxe_utils: Add fallback support
When configured correctly, we can detect when boot fails after the boot
process has been handed over to the kernel through the use of U-Boot's
bootcount support. In some instances, such as when we are performing
atomic updates via a system such as OSTree, it is desirable to provide a
fallback option so that we can return to a previous (hopefully working)
state.
Add a "fallback" option to the supported extlinux configuration options
that points to a label like "default" so that we can utilise this in
later commits.
Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/pxe_utils.c b/boot/pxe_utils.c
index 4e27842..a80119c 100644
--- a/boot/pxe_utils.c
+++ b/boot/pxe_utils.c
@@ -781,6 +781,7 @@
T_IPAPPEND,
T_BACKGROUND,
T_KASLRSEED,
+ T_FALLBACK,
T_INVALID
};
@@ -814,6 +815,7 @@
{"ipappend", T_IPAPPEND,},
{"background", T_BACKGROUND,},
{"kaslrseed", T_KASLRSEED,},
+ {"fallback", T_FALLBACK,},
{NULL, T_INVALID}
};
@@ -1356,6 +1358,18 @@
break;
+ case T_FALLBACK:
+ err = parse_sliteral(&p, &label_name);
+
+ if (label_name) {
+ if (cfg->fallback_label)
+ free(cfg->fallback_label);
+
+ cfg->fallback_label = label_name;
+ }
+
+ break;
+
case T_INCLUDE:
err = handle_include(ctx, &p,
base + ALIGN(strlen(b), 4), cfg,
@@ -1395,6 +1409,7 @@
free(cfg->title);
free(cfg->default_label);
+ free(cfg->fallback_label);
list_for_each_safe(pos, n, &cfg->labels) {
label = list_entry(pos, struct pxe_label, list);