[PATCH] winedbg: Report library load/unload events to GDB.

[Anton Baskanov]

This allows GDB to load symbols and resolve pending breakpoints for
dynamically loaded DLLs.

Signed-off-by: Anton Baskanov 
---
 programs/winedbg/gdbproxy.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/programs/winedbg/gdbproxy.c b/programs/winedbg/gdbproxy.c
index b8a8a1da2f8..4fbb3cdff59 100644
--- a/programs/winedbg/gdbproxy.c
+++ b/programs/winedbg/gdbproxy.c
@@ -395,7 +395,7 @@ static BOOL handle_exception(struct gdb_context* gdbctx, EXCEPTION_DEBUG_INFO* e
     }
 }

-static BOOL handle_debug_event(struct gdb_context* gdbctx)
+static BOOL handle_debug_event(struct gdb_context* gdbctx, BOOL stop_on_dll_load)
 {
     DEBUG_EVENT *de = &gdbctx->de;
     struct dbg_thread *thread;
@@ -456,6 +456,8 @@ static BOOL handle_debug_event(struct gdb_context* gdbctx)
                 de->u.LoadDll.nDebugInfoSize);
         dbg_load_module(gdbctx->process->handle, de->u.LoadDll.hFile, u.buffer,
                         (DWORD_PTR)de->u.LoadDll.lpBaseOfDll, 0);
+        if (stop_on_dll_load)
+            break;
         return TRUE;

case UNLOAD_DLL_DEBUG_EVENT:
@@ -463,6 +465,8 @@ static BOOL handle_debug_event(struct gdb_context* gdbctx)
                 de->dwProcessId, de->dwThreadId, de->u.UnloadDll.lpBaseOfDll);
         SymUnloadModule(gdbctx->process->handle,
                         (DWORD_PTR)de->u.UnloadDll.lpBaseOfDll);
+        if (stop_on_dll_load)
+            break;
         return TRUE;

case EXCEPTION_DEBUG_EVENT:
@@ -596,7 +600,7 @@ static void    wait_for_debuggee(struct gdb_context* gdbctx)
    			break;
    		} 
    	}
-        if (!handle_debug_event(gdbctx))
+        if (!handle_debug_event(gdbctx, TRUE))
             break;
         ContinueDebugEvent(gdbctx->de.dwProcessId, gdbctx->de.dwThreadId, DBG_CONTINUE);
     }
@@ -916,6 +920,15 @@ static enum packet_return packet_reply_status(struct gdb_context* gdbctx)
         packet_reply_val(gdbctx, gdbctx->de.u.ExitProcess.dwExitCode, 4);
         packet_reply_close(gdbctx);
         return packet_done | packet_last_f;
+
+    case LOAD_DLL_DEBUG_EVENT:
+    case UNLOAD_DLL_DEBUG_EVENT:
+        packet_reply_open(gdbctx);
+        packet_reply_add(gdbctx, "T");
+        packet_reply_val(gdbctx, SIGTRAP, 1);
+        packet_reply_add(gdbctx, "library:;");
+        packet_reply_close(gdbctx);
+        return packet_done;
     }
 }

@@ -2161,7 +2174,7 @@ static BOOL gdb_startup(struct gdb_context* gdbctx, unsigned flags, unsigned por
         goto cleanup;

/* step 2: do the process internal creation */
-    handle_debug_event(gdbctx);
+    handle_debug_event(gdbctx, FALSE);

/* step 3: fire up gdb (if requested) */
     if (flags & FLAG_NO_START)
@@ -2250,7 +2263,7 @@ static BOOL gdb_init_context(struct gdb_context* gdbctx, unsigned flags, unsigne
             /* gdbctx->dwProcessId = pid; */
             if (!gdb_startup(gdbctx, flags, port)) return FALSE;
         }
-        else if (!handle_debug_event(gdbctx))
+        else if (!handle_debug_event(gdbctx, FALSE))
             break;
         ContinueDebugEvent(gdbctx->de.dwProcessId, gdbctx->de.dwThreadId, DBG_CONTINUE);
     }

[Eric Pouech]

Le 11/07/2021 à 14:54, Anton Baskanov a écrit :
> This allows GDB to load symbols and resolve pending breakpoints for
> dynamically loaded DLLs.

Hi

nothing critical, but is stop_on_dll_load usefull for DLL unload event ? 
it won't happen at startup, so my guess is that stop_on_dll_load is 
always TRUE for unload events!

and it would be consistent with the naming of the parameter <g>

my 2 cents

[Anton Baskanov]

On понедельник, 12 июля 2021 г. 18:27:11 +07 you wrote:
> Le 11/07/2021 à 14:54, Anton Baskanov a écrit :
> > This allows GDB to load symbols and resolve pending breakpoints for
> > dynamically loaded DLLs.
>
> Hi
>
> nothing critical, but is stop_on_dll_load usefull for DLL unload event ?
> it won't happen at startup, so my guess is that stop_on_dll_load is
> always TRUE for unload events!
>
> and it would be consistent with the naming of the parameter <g>
>
> my 2 cents

Hi Eric,

Thanks for the review. Actually, there is a DLL that is unloaded at startup: 
during kernelbase.dll initialization init_locale() calls 
GetDynamicTimeZoneInformation(), which calls RegLoadMUIStringW(), which loads 
and then unloads tzres.dll. I've renamed stop_on_dll_load to 
stop_on_dll_load_unload in v2.