From 11887cf93aa8f046610136e2ce3afd3100efc9a5 Mon Sep 17 00:00:00 2001
From: Joel Brobecker <brobecker@adacore.com>
Date: Thu, 12 Dec 2013 12:53:45 -0500
Subject: [PATCH] [gdbserver] nameless LOAD_DLL_DEBUG_EVENT causes ntdll.dll
 to be missing

This is the gdbserver-equivalent of the change made in GDB to handle
the case, in x64 windows version 2012, where the kernel produces
a LOAD_DLL_DEBUG_EVENT where the name of the associated DLL cannot
be determined at that time, and thus has to be processed later.

The visible symptom is that ntdll.dll is missing from the list of
shared libraries known to be mapped by the inferior, with other
side-effects such as failure to unwind through code provided by
that DLL (such as exception handling routines).

gdb/gdbserver/ChangeLog:

	* Makefile.in (OBS): Add safe-ctype.o and lbasename.o.
	(safe-ctype.o, lbasename.o): New rules.
	* win32-low.c (win32_ensure_ntdll_loaded): New function.
	(do_initial_child_stuff): Add call to win32_ensure_ntdll_loaded.
---
 gdb/gdbserver/Makefile.in |    8 ++++-
 gdb/gdbserver/win32-low.c |   68 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 1 deletions(-)

diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index 641ea17..67d3a09 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -176,7 +176,7 @@ OBS = agent.o ax.o inferiors.o regcache.o remote-utils.o server.o signals.o \
       target.o waitstatus.o utils.o version.o vec.o gdb_vecs.o \
       mem-break.o hostio.o event-loop.o tracepoint.o xml-utils.o \
       common-utils.o ptid.o buffer.o format.o filestuff.o dll.o notif.o \
-      tdesc.o $(XML_BUILTIN) $(DEPFILES) $(LIBOBJS)
+      tdesc.o safe-ctype.o lbasename.o $(XML_BUILTIN) $(DEPFILES) $(LIBOBJS)
 GDBREPLAY_OBS = gdbreplay.o version.o
 GDBSERVER_LIBS = @GDBSERVER_LIBS@
 XM_CLIBS = @LIBS@
@@ -543,6 +543,12 @@ vasprintf.o: $(srcdir)/../../libiberty/vasprintf.c
 vsnprintf.o: $(srcdir)/../../libiberty/vsnprintf.c
 	$(COMPILE) $<
 	$(POSTCOMPILE)
+safe-ctype.o: $(srcdir)/../../libiberty/safe-ctype.c
+	$(COMPILE) $<
+	$(POSTCOMPILE)
+lbasename.o: $(srcdir)/../../libiberty/lbasename.c
+	$(COMPILE) $<
+	$(POSTCOMPILE)
 
 aarch64.c : $(srcdir)/../regformats/aarch64.dat $(regdat_sh)
 	$(SHELL) $(regdat_sh) $(srcdir)/../regformats/aarch64.dat aarch64.c
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index a4c9e77..a5f9b9d 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -105,6 +105,7 @@ typedef BOOL (WINAPI *winapi_GenerateConsoleCtrlEvent) (DWORD, DWORD);
 static ptid_t win32_wait (ptid_t ptid, struct target_waitstatus *ourstatus,
 			  int options);
 static void win32_resume (struct thread_resume *resume_info, size_t n);
+static void win32_ensure_ntdll_loaded (void);
 
 /* Get the thread ID from the current selected inferior (the current
    thread).  */
@@ -371,6 +372,8 @@ do_initial_child_stuff (HANDLE proch, DWORD pid, int attached)
 	win32_resume (&resume, 1);
       }
     }
+
+  win32_ensure_ntdll_loaded ();
 }
 
 /* Resume all artificially suspended threads if we are continuing
@@ -1134,6 +1137,71 @@ failed:
   return 0;
 }
 
+static void
+win32_ensure_ntdll_loaded (void)
+{
+  struct inferior_list_entry *dll_e;
+  size_t i;
+  HMODULE dh_buf[1];
+  HMODULE *DllHandle = dh_buf;
+  DWORD cbNeeded;
+  BOOL ok;
+
+  for (dll_e = all_dlls.head; dll_e != NULL; dll_e = dll_e->next)
+    {
+      struct dll_info *dll = (struct dll_info *) dll_e;
+
+      if (strcasecmp (lbasename (dll->name), "ntdll.dll") == 0)
+	return;
+    }
+
+  if (!load_psapi ())
+    return;
+
+  cbNeeded = 0;
+  ok = (*win32_EnumProcessModules) (current_process_handle,
+				    DllHandle,
+				    sizeof (HMODULE),
+				    &cbNeeded);
+
+  if (!ok || !cbNeeded)
+    return;
+
+  DllHandle = (HMODULE *) alloca (cbNeeded);
+  if (!DllHandle)
+    return;
+
+  ok = (*win32_EnumProcessModules) (current_process_handle,
+				    DllHandle,
+				    cbNeeded,
+				    &cbNeeded);
+  if (!ok)
+    return;
+
+  for (i = 0; i < ((size_t) cbNeeded / sizeof (HMODULE)); i++)
+    {
+      MODULEINFO mi;
+      char dll_name[MAX_PATH];
+
+      if (!(*win32_GetModuleInformation) (current_process_handle,
+					  DllHandle[i],
+					  &mi,
+					  sizeof (mi)))
+	continue;
+      if ((*win32_GetModuleFileNameExA) (current_process_handle,
+					 DllHandle[i],
+					 dll_name,
+					 MAX_PATH) == 0)
+	continue;
+      if (strcasecmp (lbasename (dll_name), "ntdll.dll") == 0)
+	{
+	  win32_add_one_solib (dll_name,
+			       (CORE_ADDR) (uintptr_t) mi.lpBaseOfDll);
+	  return;
+	}
+    }
+}
+
 typedef HANDLE (WINAPI *winapi_CreateToolhelp32Snapshot) (DWORD, DWORD);
 typedef BOOL (WINAPI *winapi_Module32First) (HANDLE, LPMODULEENTRY32);
 typedef BOOL (WINAPI *winapi_Module32Next) (HANDLE, LPMODULEENTRY32);
-- 
1.7.9