[RFA 3/3] gdbserver/Windows: Rely purely on event info when handling DLL load event

[Joel Brobecker]

This is the GDBserver counterpart of a change we recently made in
GDB to only rely on get_image_name to determine its name.

This simplification, in turn, allows us to remove a fair amount of
functions and globals which now become unused.

gdb/gdbserver/ChangeLog:

	* win32-low.c (psapi_get_dll_name,
	* win32_CreateToolhelp32Snapshot): Delete.
	(win32_CreateToolhelp32Snapshot, win32_Module32First)
	(win32_Module32Next, load_toolhelp, toolhelp_get_dll_name):
	Delete.
	(handle_load_dll): Add function description.
	Remove code using psapi_get_dll_name and toolhelp_get_dll_name.
---
 gdb/gdbserver/win32-low.c | 171 +++-------------------------------------------
 1 file changed, 8 insertions(+), 163 deletions(-)

diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index 009f9fe..9c7284f 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -1101,73 +1101,6 @@ load_psapi (void)
 	  && win32_GetModuleFileNameExA != NULL);
 }
 
-static int
-psapi_get_dll_name (LPVOID BaseAddress, char *dll_name_ret)
-{
-  DWORD len;
-  MODULEINFO mi;
-  size_t i;
-  HMODULE dh_buf[1];
-  HMODULE *DllHandle = dh_buf;
-  DWORD cbNeeded;
-  BOOL ok;
-
-  if (!load_psapi ())
-    goto failed;
-
-  cbNeeded = 0;
-  ok = (*win32_EnumProcessModules) (current_process_handle,
-				    DllHandle,
-				    sizeof (HMODULE),
-				    &cbNeeded);
-
-  if (!ok || !cbNeeded)
-    goto failed;
-
-  DllHandle = (HMODULE *) alloca (cbNeeded);
-  if (!DllHandle)
-    goto failed;
-
-  ok = (*win32_EnumProcessModules) (current_process_handle,
-				    DllHandle,
-				    cbNeeded,
-				    &cbNeeded);
-  if (!ok)
-    goto failed;
-
-  for (i = 0; i < ((size_t) cbNeeded / sizeof (HMODULE)); i++)
-    {
-      if (!(*win32_GetModuleInformation) (current_process_handle,
-					  DllHandle[i],
-					  &mi,
-					  sizeof (mi)))
-	{
-	  DWORD err = GetLastError ();
-	  error ("Can't get module info: (error %d): %s\n",
-		 (int) err, strwinerror (err));
-	}
-
-      if (mi.lpBaseOfDll == BaseAddress)
-	{
-	  len = (*win32_GetModuleFileNameExA) (current_process_handle,
-					       DllHandle[i],
-					       dll_name_ret,
-					       MAX_PATH);
-	  if (len == 0)
-	    {
-	      DWORD err = GetLastError ();
-	      error ("Error getting dll name: (error %d): %s\n",
-		     (int) err, strwinerror (err));
-	    }
-	  return 1;
-	}
-    }
-
-failed:
-  dll_name_ret[0] = '\0';
-  return 0;
-}
-
 #ifndef _WIN32_WCE
 
 /* Iterate over all DLLs currently mapped by our inferior, and
@@ -1229,114 +1162,26 @@ typedef HANDLE (WINAPI *winapi_CreateToolhelp32Snapshot) (DWORD, DWORD);
 typedef BOOL (WINAPI *winapi_Module32First) (HANDLE, LPMODULEENTRY32);
 typedef BOOL (WINAPI *winapi_Module32Next) (HANDLE, LPMODULEENTRY32);
 
-static winapi_CreateToolhelp32Snapshot win32_CreateToolhelp32Snapshot;
-static winapi_Module32First win32_Module32First;
-static winapi_Module32Next win32_Module32Next;
 #ifdef _WIN32_WCE
 typedef BOOL (WINAPI *winapi_CloseToolhelp32Snapshot) (HANDLE);
 static winapi_CloseToolhelp32Snapshot win32_CloseToolhelp32Snapshot;
 #endif
 
-static BOOL
-load_toolhelp (void)
-{
-  static int toolhelp_loaded = 0;
-  static HMODULE dll = NULL;
-
-  if (!toolhelp_loaded)
-    {
-      toolhelp_loaded = 1;
-#ifndef _WIN32_WCE
-      dll = GetModuleHandle (_T("KERNEL32.DLL"));
-#else
-      dll = LoadLibrary (L"TOOLHELP.DLL");
-#endif
-      if (!dll)
-	return FALSE;
+/* Handle a DLL load event.
 
-      win32_CreateToolhelp32Snapshot =
-	GETPROCADDRESS (dll, CreateToolhelp32Snapshot);
-      win32_Module32First = GETPROCADDRESS (dll, Module32First);
-      win32_Module32Next = GETPROCADDRESS (dll, Module32Next);
-#ifdef _WIN32_WCE
-      win32_CloseToolhelp32Snapshot =
-	GETPROCADDRESS (dll, CloseToolhelp32Snapshot);
-#endif
-    }
-
-  return (win32_CreateToolhelp32Snapshot != NULL
-	  && win32_Module32First != NULL
-	  && win32_Module32Next != NULL
-#ifdef _WIN32_WCE
-	  && win32_CloseToolhelp32Snapshot != NULL
-#endif
-	  );
-}
-
-static int
-toolhelp_get_dll_name (LPVOID BaseAddress, char *dll_name_ret)
-{
-  HANDLE snapshot_module;
-  MODULEENTRY32 modEntry = { sizeof (MODULEENTRY32) };
-  int found = 0;
-
-  if (!load_toolhelp ())
-    return 0;
-
-  snapshot_module = win32_CreateToolhelp32Snapshot (TH32CS_SNAPMODULE,
-						    current_event.dwProcessId);
-  if (snapshot_module == INVALID_HANDLE_VALUE)
-    return 0;
-
-  /* Ignore the first module, which is the exe.  */
-  if (win32_Module32First (snapshot_module, &modEntry))
-    while (win32_Module32Next (snapshot_module, &modEntry))
-      if (modEntry.modBaseAddr == BaseAddress)
-	{
-#ifdef UNICODE
-	  wcstombs (dll_name_ret, modEntry.szExePath, MAX_PATH + 1);
-#else
-	  strcpy (dll_name_ret, modEntry.szExePath);
-#endif
-	  found = 1;
-	  break;
-	}
-
-#ifdef _WIN32_WCE
-  win32_CloseToolhelp32Snapshot (snapshot_module);
-#else
-  CloseHandle (snapshot_module);
-#endif
-  return found;
-}
+   This function assumes that this event did not occur during inferior
+   initialization, where their event info may be incomplete (see
+   do_initial_child_stuff and win32_add_all_dlls for more info on
+   how we handle DLL loading during that phase).  */
 
 static void
 handle_load_dll (void)
 {
   LOAD_DLL_DEBUG_INFO *event = &current_event.u.LoadDll;
-  char dll_buf[MAX_PATH + 1];
-  char *dll_name = NULL;
-
-  dll_buf[0] = dll_buf[sizeof (dll_buf) - 1] = '\0';
-
-  /* Windows does not report the image name of the dlls in the debug
-     event on attaches.  We resort to iterating over the list of
-     loaded dlls looking for a match by image base.  */
-  if (!psapi_get_dll_name (event->lpBaseOfDll, dll_buf))
-    {
-      if (!server_waiting)
-	/* On some versions of Windows and Windows CE, we can't create
-	   toolhelp snapshots while the inferior is stopped in a
-	   LOAD_DLL_DEBUG_EVENT due to a dll load, but we can while
-	   Windows is reporting the already loaded dlls.  */
-	toolhelp_get_dll_name (event->lpBaseOfDll, dll_buf);
-    }
-
-  dll_name = dll_buf;
+  char *dll_name;
 
-  if (*dll_name == '\0')
-    dll_name = get_image_name (current_process_handle,
-			       event->lpImageName, event->fUnicode);
+  dll_name = get_image_name (current_process_handle,
+			     event->lpImageName, event->fUnicode);
   if (!dll_name)
     return;
 
-- 
1.8.3.2