From 378383ea3bf04ab6e083c597298db63ff665837e Mon Sep 17 00:00:00 2001
From: Daniel Silverstone <dsilvers@digital-scurf.org>
Date: Mon, 6 May 2019 15:09:39 +0100
Subject: [PATCH] Support context dump safely in duktape

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>
---
 content/handlers/javascript/duktape/dukky.c | 23 +++++++++++++++++++--
 content/handlers/javascript/duktape/dukky.h |  3 +++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/content/handlers/javascript/duktape/dukky.c b/content/handlers/javascript/duktape/dukky.c
index e9e579d4d..c3b956902 100644
--- a/content/handlers/javascript/duktape/dukky.c
+++ b/content/handlers/javascript/duktape/dukky.c
@@ -669,6 +669,8 @@ jsobject *js_newcompartment(jscontext *ctx, void *win_priv, void *doc_priv)
 	duk_pop(CTX);
 	/* ... */
 
+	dukky_log_stack_frame(CTX, "New compartment created");
+
 	return (jsobject *)ctx;
 }
 
@@ -698,8 +700,8 @@ static void dukky_dump_error(duk_context *ctx)
 {
 	/* stack is ..., errobj */
 	duk_idx_t stacktop = duk_get_top(ctx);
-	if (!duk_is_error(ctx, stacktop - 1)) {
-		NSLOG(dukky, INFO, "Uncaught non-Error derived error in JS: %s", duk_safe_to_string(ctx, stacktop - 1));
+	if (!duk_is_error(ctx, -1)) {
+		NSLOG(dukky, INFO, "Uncaught non-Error derived error in JS: %s", duk_safe_to_string(ctx, -1));
 	} else {
 #define GETTER(what)						\
 		if (duk_has_prop_string(ctx, stacktop - 1, what)) {	\
@@ -761,6 +763,23 @@ void dukky_push_generics(duk_context *ctx, const char *generic)
 	/* ..., generic */
 }
 
+static duk_int_t dukky_push_context_dump(duk_context *ctx, void *udata)
+{
+	duk_push_context_dump(ctx);
+	return 1;
+}
+
+void dukky_log_stack_frame(duk_context *ctx, const char * reason)
+{
+	if (duk_safe_call(ctx, dukky_push_context_dump, NULL, 0, 1) != 0) {
+		duk_pop(ctx);
+		duk_push_string(ctx, "[???]");
+	}
+	NSLOG(dukky, DEEPDEBUG, "%s, stack is: %s", reason, duk_safe_to_string(ctx, -1));
+	duk_pop(ctx);
+}
+
+
 /* exported interface documented in js.h */
 bool
 js_exec(jscontext *ctx, const uint8_t *txt, size_t txtlen, const char *name)
diff --git a/content/handlers/javascript/duktape/dukky.h b/content/handlers/javascript/duktape/dukky.h
index 93d416983..5a67951dc 100644
--- a/content/handlers/javascript/duktape/dukky.h
+++ b/content/handlers/javascript/duktape/dukky.h
@@ -54,4 +54,7 @@ duk_int_t dukky_pcall(duk_context *ctx, duk_size_t argc, bool reset_timeout);
 /* Push a generics function onto the stack */
 void dukky_push_generics(duk_context *ctx, const char *generic);
 
+/* Log the current stack frame if possible */
+void dukky_log_stack_frame(duk_context *ctx, const char * reason);
+
 #endif