1 files changed, 78 insertions, 0 deletions
diff --git a/winsup/cygwin/sigproc.h b/winsup/cygwin/sigproc.h
index 2900da4cc..ffe75a8d3 100644
--- a/winsup/cygwin/sigproc.h
+++ b/winsup/cygwin/sigproc.h
@@ -11,6 +11,7 @@ details. */
 
 #pragma once
 #include <signal.h>
+#include "sync.h"
 
 #ifdef NSIG
 enum
@@ -121,4 +122,81 @@ extern char myself_nowait_dummy[];
 
 extern struct sigaction *global_sigs;
 
+class lock_signals
+{
+  bool worked;
+public:
+  lock_signals ()
+  {
+    worked = sig_send (NULL, __SIGHOLD) == 0;
+  }
+  operator int () const
+  {
+    return worked;
+  }
+  void dont_bother ()
+  {
+    worked = false;
+  }
+  ~lock_signals ()
+  {
+    if (worked)
+      sig_send (NULL, __SIGNOHOLD);
+  }
+};
+
+class lock_pthread
+{
+  bool bother;
+public:
+  lock_pthread (): bother (1)
+  {
+    pthread::atforkprepare ();
+  }
+  void dont_bother ()
+  {
+    bother = false;
+  }
+  ~lock_pthread ()
+  {
+    if (bother)
+      pthread::atforkparent ();
+  }
+};
+
+class hold_everything
+{
+public: /* DELETEME*/
+  bool ischild;
+  /* Note the order of the locks below.  It is important,
+     to avoid races, that the lock order be preserved.
+
+     pthread is first because it serves as a master lock
+     against other forks being attempted while this one is active.
+
+     signals is next to stop signal processing for the duration
+     of the fork.
+
+     process is last.  If it is put before signals, then a deadlock
+     could be introduced if the process attempts to exit due to a signal. */
+  lock_pthread pthread;
+  lock_signals signals;
+  lock_process process;
+
+public:
+  hold_everything (bool x = false): ischild (x) {}
+  operator int () const {return signals;}
+
+  ~hold_everything()
+  {
+    if (ischild)
+      {
+	pthread.dont_bother ();
+	process.dont_bother ();
+	signals.dont_bother ();
+      }
+  }
+
+};
+
 #define myself_nowait ((_pinfo *) myself_nowait_dummy)