From 02e76e727b95dc21dc07d1fe8424b68e37e91a83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Sch=C3=A4pers?= <bjoern@hazardy.de>
Date: Sat, 6 Jan 2024 22:53:54 +0100
Subject: [PATCH 3/3] libbacktrace: Add loaded dlls after initialize

libbacktrace/Changelog:

	* pecoff.c [HAVE_WINDOWS_H]:
	  (dll_notification_data): Added
	  (dll_notification_context): Added
	  (dll_notification): Added
	  (backtrace_initialize): Use LdrRegisterDllNotification to load
	                          debug information of later loaded
	                          dlls.
---
 libbacktrace/pecoff.c | 102 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 101 insertions(+), 1 deletion(-)

diff --git a/libbacktrace/pecoff.c b/libbacktrace/pecoff.c
index 647baa39640..bfe12cc2a0a 100644
--- a/libbacktrace/pecoff.c
+++ b/libbacktrace/pecoff.c
@@ -62,6 +62,32 @@ POSSIBILITY OF SUCH DAMAGE.  */
 #undef Module32Next
 #endif
 #endif
+
+#if defined(_ARM_)
+#define NTAPI
+#else
+#define NTAPI __stdcall
+#endif
+
+/* This is a simplified (but binary compatible) version of what Microsoft
+   defines in their documentation. */
+struct dll_notifcation_data
+{
+  ULONG reserved;
+  /* The name as UNICODE_STRING struct. */
+  PVOID full_dll_name;
+  PVOID base_dll_name;
+  PVOID dll_base;
+  ULONG size_of_image;
+};
+
+typedef LONG NTSTATUS;
+typedef VOID CALLBACK (*LDR_DLL_NOTIFICATION)(ULONG,
+					      struct dll_notifcation_data*,
+					      PVOID);
+typedef NTSTATUS NTAPI (*LDR_REGISTER_FUNCTION)(ULONG,
+						LDR_DLL_NOTIFICATION, PVOID,
+						PVOID*);
 #endif
 
 /* Coff file header.  */
@@ -912,7 +938,8 @@ coff_add (struct backtrace_state *state, int descriptor,
   return 0;
 }
 
-#if defined(HAVE_WINDOWS_H) && !defined(HAVE_TLHELP32_H)
+#ifdef HAVE_WINDOWS_H
+#ifndef HAVE_TLHELP32_H
 static void
 free_modules (struct backtrace_state *state,
 	      backtrace_error_callback error_callback, void *data,
@@ -958,6 +985,51 @@ get_all_modules (struct backtrace_state *state,
     }
 }
 #endif
+struct dll_notification_context
+{
+  struct backtrace_state *state;
+  backtrace_error_callback error_callback;
+  void *data;
+};
+
+VOID CALLBACK
+dll_notification (ULONG reason,
+struct dll_notifcation_data *notification_data,
+PVOID context)
+{
+  char module_name[MAX_PATH];
+  int descriptor;
+  struct dll_notification_context* dll_context =
+    (struct dll_notification_context*) context;
+  struct backtrace_state *state = dll_context->state;
+  void *data = dll_context->data;
+  backtrace_error_callback error_callback = dll_context->data;
+  fileline fileline;
+  int found_sym;
+  int found_dwarf;
+  HMODULE module_handle;
+
+  if (reason != /*LDR_DLL_NOTIFICATION_REASON_LOADED*/1)
+    return;
+
+  if (!GetModuleHandleEx (GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS
+			  | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
+			  (TCHAR*) notification_data->dll_base,
+			  &module_handle))
+    return;
+
+  if (!GetModuleFileNameA ((HMODULE) module_handle, module_name, MAX_PATH - 1))
+    return;
+
+  descriptor = backtrace_open (module_name, error_callback, data, NULL);
+
+  if (descriptor < 0)
+    return;
+
+  coff_add (state, descriptor, error_callback, data, &fileline, &found_sym,
+	    &found_dwarf, (uintptr_t) module_handle);
+}
+#endif
 
 /* Initialize the backtrace data we need from an ELF executable.  At
    the ELF level, all we need to do is find the debug info
@@ -978,6 +1050,7 @@ backtrace_initialize (struct backtrace_state *state,
 #ifdef HAVE_WINDOWS_H
   fileline module_fileline_fn;
   int module_found_sym;
+  HMODULE nt_dll_handle;
 
 #ifdef HAVE_TLHELP32_H
   HANDLE snapshot;
@@ -1065,6 +1138,33 @@ backtrace_initialize (struct backtrace_state *state,
   if (modules)
     free_modules (state, error_callback, data, &modules, bytes_allocated_for_modules);
 #endif
+
+  nt_dll_handle = GetModuleHandle (TEXT ("ntdll.dll"));
+  if (nt_dll_handle)
+    {
+      LDR_REGISTER_FUNCTION register_func;
+      const char register_name[] = "LdrRegisterDllNotification";
+      register_func = (LDR_REGISTER_FUNCTION) GetProcAddress (nt_dll_handle,
+							      register_name);
+
+      if (register_func)
+	{
+	  PVOID cookie;
+	  struct dll_notification_context *context
+	    = backtrace_alloc (state,
+			       sizeof(struct dll_notification_context),
+			       error_callback, data);
+
+	  if (context)
+	    {
+	      context->state = state;
+	      context->data = data;
+	      context->error_callback = error_callback;
+
+	      register_func (0, &dll_notification, context, &cookie);
+	    }
+	}
+    }
 #endif
 
   if (!state->threaded)
-- 
2.42.1