From f8af64be8716333f179a1d240ef42fab5188b607 Mon Sep 17 00:00:00 2001
From: Christopher Faylor <me@cgf.cx>
Date: Sat, 13 Mar 2010 19:34:35 +0000
Subject: [PATCH] * spinlock.h: New file. (spinlock): New class. * shared.cc:
 Include spinlock.h. (memory_init): Use new spinlock methods rather than
 roll-your-own.  Time out after ten seconds if shared_mem_inited is not
 initialized. * sync.h: Update copyright.  Remove vanity attribution. *
 sigproc.cc (sigproc_terminate): Avoid attempts to kill the signal thread
 while we're still initializing or suffer a deadlock.

---
 winsup/cygwin/ChangeLog  | 13 ++++++++++
 winsup/cygwin/shared.cc  | 53 ++++++++++++++++------------------------
 winsup/cygwin/sigproc.cc |  4 ++-
 winsup/cygwin/spinlock.h | 40 ++++++++++++++++++++++++++++++
 winsup/cygwin/sync.h     |  4 +--
 5 files changed, 78 insertions(+), 36 deletions(-)
 create mode 100644 winsup/cygwin/spinlock.h

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index e476c7e4f..c5713914c 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,16 @@
+2010-03-13  Christopher Faylor  <me+cygwin@cgf.cx>
+
+	* spinlock.h: New file.
+	(spinlock): New class.
+	* shared.cc: Include spinlock.h.
+	(memory_init): Use new spinlock methods rather than roll-your-own.
+	Time out after ten seconds if shared_mem_inited is not initialized.
+
+	* sync.h: Update copyright.  Remove vanity attribution.
+
+	* sigproc.cc (sigproc_terminate): Avoid attempts to kill the signal
+	thread while we're still initializing or suffer a deadlock.
+
 2010-03-12  Christopher Faylor  <me+cygwin@cgf.cx>
 
 	Throughout change all calls of low_priority_sleep (0) to yield ().
diff --git a/winsup/cygwin/shared.cc b/winsup/cygwin/shared.cc
index fcca6f40f..6e166f3fa 100644
--- a/winsup/cygwin/shared.cc
+++ b/winsup/cygwin/shared.cc
@@ -23,6 +23,7 @@ details. */
 #include "registry.h"
 #include "cygwin_version.h"
 #include "pwdgrp.h"
+#include "spinlock.h"
 #include "ntdll.h"
 #include <alloca.h>
 #include <wchar.h>
@@ -418,40 +419,28 @@ memory_init (bool init_cygheap)
     }
 
   /* Initialize general shared memory under spinlock control */
-  for (;;)
-    {
-      LONG smi = InterlockedExchange (&shared_mem_inited, -1);
-      if (smi < 0)
-	{
-	  yield ();
-	  continue;
-	}
+  {
+    spinlock smi (shared_mem_inited, 10000);
+    if (!smi)
+      init_installation_root ();	/* Initialize installation root dir */
 
-      if (!smi)
-	/* Initialize installation root dir */
-	init_installation_root ();
+    cygwin_shared = (shared_info *) open_shared (L"shared",
+						 CYGWIN_VERSION_SHARED_DATA,
+						 cygwin_shared_h,
+						 sizeof (*cygwin_shared),
+						 SH_CYGWIN_SHARED);
+    heap_init ();
 
-      cygwin_shared = (shared_info *) open_shared (L"shared",
-						   CYGWIN_VERSION_SHARED_DATA,
-						   cygwin_shared_h,
-						   sizeof (*cygwin_shared),
-						   SH_CYGWIN_SHARED);
-      heap_init ();
-
-      if (!smi)
-	{
-	  cygwin_shared->initialize ();
-	  /* Defer debug output printing the installation root and installation key
-	     up to this point.  Debug output except for system_printf requires
-	     the global shared memory to exist. */
-	  debug_printf ("Installation root: <%W> key: <%S>",
-			installation_root, &installation_key);
-	  smi = 1;
-	}
-
-      InterlockedExchange (&shared_mem_inited, smi);
-      break;
-    }
+    if (!smi)
+      {
+	cygwin_shared->initialize ();
+	/* Defer debug output printing the installation root and installation key
+	   up to this point.  Debug output except for system_printf requires
+	   the global shared memory to exist. */
+	debug_printf ("Installation root: <%W> key: <%S>",
+		      installation_root, &installation_key);
+      }
+  }
   user_shared_create (false);
 }
 
diff --git a/winsup/cygwin/sigproc.cc b/winsup/cygwin/sigproc.cc
index 9408b0c6d..e84690320 100644
--- a/winsup/cygwin/sigproc.cc
+++ b/winsup/cygwin/sigproc.cc
@@ -494,7 +494,9 @@ sigproc_terminate (exit_states es)
 {
   exit_states prior_exit_state = exit_state;
   exit_state = es;
-  if (prior_exit_state >= ES_FINAL)
+  if (!cygwin_finished_initializing)
+    sigproc_printf ("don't worry about signal thread");
+  else if (prior_exit_state >= ES_FINAL)
     sigproc_printf ("already performed");
   else
     {
diff --git a/winsup/cygwin/spinlock.h b/winsup/cygwin/spinlock.h
new file mode 100644
index 000000000..abf723acc
--- /dev/null
+++ b/winsup/cygwin/spinlock.h
@@ -0,0 +1,40 @@
+/* spinlock.h: Header file for cygwin time-sensitive synchronization primitive.
+
+   Copyright 2010 Red Hat, Inc.
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#ifndef _SPINLOCK_H
+#define _SPINLOCK_H
+
+#include "hires.h"
+
+class spinlock
+{
+  LONG *locker;
+  LONG val;
+public:
+  spinlock (LONG& locktest, LONGLONG timeout):
+    locker (&locktest)
+  {
+    if ((val = locktest) == 1)
+      return;
+    LONGLONG then = gtod.msecs ();
+    for (;;)
+      {
+	if ((val = InterlockedExchange (locker, -1)) != -1
+	    || (gtod.msecs () - then) >= timeout)
+	  break;
+	yield ();
+      }
+  }
+  ~spinlock () {InterlockedExchange (locker, 1);}
+  operator LONG () const {return val;}
+};
+
+#endif /*_SPINLOCK_H*/
+
diff --git a/winsup/cygwin/sync.h b/winsup/cygwin/sync.h
index dfe2c3921..5d66b97af 100644
--- a/winsup/cygwin/sync.h
+++ b/winsup/cygwin/sync.h
@@ -1,8 +1,6 @@
 /* sync.h: Header file for cygwin synchronization primitives.
 
-   Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Red Hat, Inc.
-
-   Written by Christopher Faylor <cgf@cygnus.com>
+   Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Red Hat, Inc.
 
 This file is part of Cygwin.