address review feedback

Author: bigbrett

docs/hooks.md

@@ -51,7 +51,7 @@ wolfBoot_panic()  (called on any fatal error)
 
 ## Build Configuration
 
-First, Enable hooks in your `.config`
+First, enable hooks in your `.config`:
 
 ```makefile
 # Path to a single .c file containing your hook implementations

include/hooks.h

@@ -28,6 +28,10 @@
 #ifndef WOLFBOOT_HOOKS_H
 #define WOLFBOOT_HOOKS_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct wolfBoot_image;
 
 #ifdef WOLFBOOT_HOOK_LOADER_PREINIT
@@ -46,4 +50,8 @@ void wolfBoot_hook_boot(struct wolfBoot_image *boot_img);
 void wolfBoot_hook_panic(void);
 #endif
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* WOLFBOOT_HOOKS_H */

options.mk

@@ -1154,20 +1154,28 @@ endif
 
 # wolfBoot hooks framework
 # WOLFBOOT_HOOKS_FILE: path to a single .c file containing hook definitions
-ifneq ($(WOLFBOOT_HOOKS_FILE),)
-  OBJS += $(patsubst %.c,%.o,$(WOLFBOOT_HOOKS_FILE))
-endif
+WOLFBOOT_HOOKS_ENABLED :=
 ifeq ($(WOLFBOOT_HOOK_LOADER_PREINIT),1)
   CFLAGS += -DWOLFBOOT_HOOK_LOADER_PREINIT
+  WOLFBOOT_HOOKS_ENABLED := 1
 endif
 ifeq ($(WOLFBOOT_HOOK_LOADER_POSTINIT),1)
   CFLAGS += -DWOLFBOOT_HOOK_LOADER_POSTINIT
+  WOLFBOOT_HOOKS_ENABLED := 1
 endif
 ifeq ($(WOLFBOOT_HOOK_BOOT),1)
   CFLAGS += -DWOLFBOOT_HOOK_BOOT
+  WOLFBOOT_HOOKS_ENABLED := 1
 endif
 ifeq ($(WOLFBOOT_HOOK_PANIC),1)
   CFLAGS += -DWOLFBOOT_HOOK_PANIC
+  WOLFBOOT_HOOKS_ENABLED := 1
+endif
+ifneq ($(WOLFBOOT_HOOKS_ENABLED),)
+  ifeq ($(WOLFBOOT_HOOKS_FILE),)
+    $(error WOLFBOOT_HOOKS_FILE must be set to a .c file when hooks are enabled)
+  endif
+  OBJS += $(patsubst %.c,%.o,$(WOLFBOOT_HOOKS_FILE))
 endif
 
 # Cert chain verification options