Add a function pointer to get active boot slot

bootcontrol 1.2 adds a new function to get the active boot slot
on the next boot. Since the getter is closely related to the gpt
implementation of bootcontrol, we add the header here and expose
to clients of libhardware. Devices with an old HAL should never
call this new getter function.

Bug: 173808057
Test: Vts tests for bootcontrol

Change-Id: I19135ed16bf0ba546e0a8d9cb2d521ec0a9c5bbc

1 files changed, 8 insertions, 1 deletions

diff --git a/include/hardware/boot_control.h b/include/hardware/boot_control.h
index 36a867da..abbf3f19 100644
--- a/include/hardware/boot_control.h
+++ b/include/hardware/boot_control.h
@@ -125,7 +125,14 @@ typedef struct boot_control_module {
      */
     int (*isSlotMarkedSuccessful)(struct boot_control_module *module, unsigned slot);
 
-    void* reserved[31];
+    /**
+     * Returns the active slot to boot into on the next boot. If
+     * setActiveBootSlot() has been called, the getter function should return
+     * the same slot as the one provided in the last setActiveBootSlot() call.
+     */
+    unsigned (*getActiveBootSlot)(struct boot_control_module *module);
+
+    void* reserved[30];
 } boot_control_module_t;