add the functions for multi-stage packages to updater

In order to support multi-stage recovery packages, we add the
set_stage() and get_stage() functions, which store a short string
somewhere it can be accessed across invocations of recovery.  We also
add reboot_now() which updater can invoke to immediately reboot the
device, without doing normal recovery cleanup.  (It can also choose
whether to boot off the boot or recovery partition.)

If the stage string is of the form "#/#", recovery's UI will be
augmented with a simple indicator of what stage you're in, so it
doesn't look like a reboot loop.

Change-Id: I62f7ff0bc802b549c9bcf3cc154a6bad99f94603

1 files changed, 14 insertions, 1 deletions

diff --git a/bootloader.h b/bootloader.h
index 712aa1a..c2895dd 100644
--- a/bootloader.h
+++ b/bootloader.h
@@ -38,11 +38,24 @@ extern "C" {
  * The recovery field is only written by linux and used
  * for the system to send a message to recovery or the
  * other way around.
+ *
+ * The stage field is written by packages which restart themselves
+ * multiple times, so that the UI can reflect which invocation of the
+ * package it is.  If the value is of the format "#/#" (eg, "1/3"),
+ * the UI will add a simple indicator of that status.
  */
 struct bootloader_message {
     char command[32];
     char status[32];
-    char recovery[1024];
+    char recovery[768];
+
+    // The 'recovery' field used to be 1024 bytes.  It has only ever
+    // been used to store the recovery command line, so 768 bytes
+    // should be plenty.  We carve off the last 256 bytes to store the
+    // stage string (for multistage packages) and possible future
+    // expansion.
+    char stage[32];
+    char reserved[224];
 };
 
 /* Read and write the bootloader command from the "misc" partition.