peb trampling mule

src/dbgi2/dbgi2.c

@@ -378,9 +378,10 @@ di_rdi_from_path_min_timestamp(DI_Scope *scope, String8 path, U64 min_timestamp,
       }
       
       //- rjf: parse not done, not working, asked a while ago -> ask for parse
+      B32 sent = 0;
       if(node != 0 && !node->parse_done && !node->is_working && ins_atomic_u64_eval(&node->last_time_requested_us)+1000000<os_now_microseconds())
       {
-        B32 sent = di_u2p_enqueue_key(path_normalized, min_timestamp, endt_us);
+        sent = di_u2p_enqueue_key(path_normalized, min_timestamp, endt_us);
         if(sent)
         {
           ins_atomic_u64_eval_assign(&node->last_time_requested_us, os_now_microseconds());
@@ -394,7 +395,9 @@ di_rdi_from_path_min_timestamp(DI_Scope *scope, String8 path, U64 min_timestamp,
       }
       
       //- rjf: wait on this stripe
-      os_condition_variable_wait_rw_r(stripe->cv, stripe->rw_mutex, endt_us);
+      {
+        os_condition_variable_wait_rw_r(stripe->cv, stripe->rw_mutex, endt_us);
+      }
     }
     scratch_end(scratch);
   }

src/mule/mule_peb_trample.c

@@ -0,0 +1,66 @@
+#include <windows.h>
+#include <winternl.h>
+
+static void
+HideModuleFromWindowsReload(HMODULE ModuleToFlush)
+{
+  /* NOTE(casey): Normally you cannot "reload" an executable module with the same name,
+     because Windows checks a linked list of loaded modules and assumes that if
+     it's already loaded, it doesn't need to reload it, even though it may have to because
+     it has changed on disk.
+     
+     This solution to that problem comes from some excellent spelunking by Martins Mozeiko,
+     who figured out that you could overwrite the filenames Windows stores in your process's
+     loaded module table, thus thwarting the Windows filename check against loaded modules,
+     allowing you to reload an existing module that has changed without requiring it to
+     have a different filename!
+  */
+  
+  PEB *Peb = (PEB *)__readgsqword(offsetof(TEB, ProcessEnvironmentBlock));
+  LIST_ENTRY *Head = &Peb->Ldr->InMemoryOrderModuleList;
+  for(LIST_ENTRY *Entry = Head->Flink;
+      Entry != Head;
+      Entry = Entry->Flink)
+  {
+    LDR_DATA_TABLE_ENTRY *Mod = CONTAINING_RECORD(Entry, LDR_DATA_TABLE_ENTRY, InMemoryOrderLinks);
+    if(Mod->DllBase == ModuleToFlush)
+    {
+      ZeroMemory(Mod->FullDllName.Buffer, Mod->FullDllName.Length);
+      Mod->DllBase = 0;
+      break;
+    }
+  }
+}
+
+__declspec(dllexport) void
+loop_iteration(int it)
+{
+  printf("foobar iteration #%i\n", it);
+}
+
+int main(int argument_count, char **arguments)
+{
+  char *exe_name = arguments[0];
+  HANDLE last_module = GetModuleHandle(0);
+  void (*loop_iteration_function)(int it) = (void (*)(int))GetProcAddress(last_module, "loop_iteration");
+  FILETIME last_filetime = {0};
+  int should_exit = 0;
+  for(int it = 0; !should_exit; it += 1)
+  {
+    loop_iteration_function(it);
+    Sleep(50);
+    FILETIME current_filetime = {0};
+    HANDLE current_exe_file = CreateFile(exe_name, 0, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
+    GetFileTime(current_exe_file, 0, 0, &current_filetime);
+    CloseHandle(current_exe_file);
+    if(it != 0 && CompareFileTime(&last_filetime, &current_filetime) < 0)
+    {
+      HideModuleFromWindowsReload(last_module);
+      //last_module = LoadLibrary(arguments[0]);
+      last_module = LoadLibrary("foobar.exe");
+      loop_iteration_function = (void (*)(int))GetProcAddress(last_module, "loop_iteration");
+    }
+    last_filetime = current_filetime;
+  }
+  return 0;
+}