From cc5bdf003f650ce5938640c4dd1ffd84259dcc42 Mon Sep 17 00:00:00 2001
From: Christopher Faylor <me@cgf.cx>
Date: Tue, 30 Apr 2013 23:47:01 +0000
Subject: [PATCH] * exceptions.cc (cygwin_exception::dumpstack): Guard against
 wild pointer dereference. (CYG_EXC_CONTINUE_EXECUTION): Define based on
 standard Windows definition. (CYG_EXC_CONTINUE_SEARCH): Ditto.
 (exception::handle): Move andreas detection earlier.  Make comment clearer.
 (signal_exit): Set core-dumped flag.

---
 winsup/cygwin/ChangeLog     | 11 ++++++++
 winsup/cygwin/exceptions.cc | 51 +++++++++++++++++++++----------------
 2 files changed, 40 insertions(+), 22 deletions(-)

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index a2d3628b9..60e0a301f 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,14 @@
+2013-04-30  Christopher Faylor  <me.cygwin2013@cgf.cx>
+
+	* exceptions.cc (cygwin_exception::dumpstack): Guard against wild
+	pointer dereference.
+	(CYG_EXC_CONTINUE_EXECUTION): Define based on standard Windows
+	definition.
+	(CYG_EXC_CONTINUE_SEARCH): Ditto.
+	(exception::handle): Move andreas detection earlier.  Make comment
+	clearer.
+	(signal_exit): Set core-dumped flag.
+
 2013-04-30  Christopher Faylor  <me.cygwin2013@cgf.cx>
 
 	* i686.din: New file.
diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index 083d87ff4..31d84bd24 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -344,6 +344,9 @@ void
 cygwin_exception::dumpstack ()
 {
   static bool already_dumped;
+  myfault efault;
+  if (efault.faulted ())
+    return;
 
   if (already_dumped || cygheap->rlim_core == 0Ul)
     return;
@@ -553,8 +556,8 @@ bool exception::handler_installed NO_COPY;
 int
 exception::handle (LPEXCEPTION_POINTERS ep)
 #else
-#define CYG_EXC_CONTINUE_EXECUTION	0
-#define CYG_EXC_CONTINUE_SEARCH		1
+#define CYG_EXC_CONTINUE_EXECUTION	ExceptionContinueExecution
+#define CYG_EXC_CONTINUE_SEARCH		ExceptionContinueSearch
 
 int
 exception::handle (EXCEPTION_RECORD *e, exception_list *frame, CONTEXT *in, void *)
@@ -563,6 +566,9 @@ exception::handle (EXCEPTION_RECORD *e, exception_list *frame, CONTEXT *in, void
   static bool NO_COPY debugging;
   _cygtls& me = _my_tls;
 
+  if (me.andreas)
+    me.andreas->leave ();	/* Return from a "san" caught fault */
+
 #ifdef __x86_64__
   EXCEPTION_RECORD *e = ep->ExceptionRecord;
   CONTEXT *in = ep->ContextRecord;
@@ -574,8 +580,8 @@ exception::handle (EXCEPTION_RECORD *e, exception_list *frame, CONTEXT *in, void
       return CYG_EXC_CONTINUE_EXECUTION;
     }
 
-  /* If we're exiting, don't do anything here.  Returning 1
-     tells Windows to keep looking for an exception handler.  */
+  /* If we're exiting, tell Windows to keep looking for an
+     exception handler.  */
   if (exit_state || e->ExceptionFlags)
     return CYG_EXC_CONTINUE_SEARCH;
 
@@ -689,9 +695,6 @@ exception::handle (EXCEPTION_RECORD *e, exception_list *frame, CONTEXT *in, void
       return CYG_EXC_CONTINUE_SEARCH;
     }
 
-  if (me.andreas)
-    me.andreas->leave ();	/* Return from a "san" caught fault */
-
   debug_printf ("In cygwin_except_handler exception %y at %p sp %p", e->ExceptionCode, in->_GR(ip), in->_GR(sp));
   debug_printf ("In cygwin_except_handler signal %d at %p", si.si_signo, in->_GR(ip));
 
@@ -1204,29 +1207,33 @@ signal_exit (int sig, siginfo_t *si)
       case SIGTRAP:
       case SIGXCPU:
       case SIGXFSZ:
-       if (try_to_debug ())
-	 break;
-       if (si->si_code != SI_USER && si->si_cyg)
-	 ((cygwin_exception *) si->si_cyg)->dumpstack ();
-       else
-	 {
-	   CONTEXT c;
-	   c.ContextFlags = CONTEXT_FULL;
-	   RtlCaptureContext (&c);
+	sig |= 0x80;		/* Flag that we've "dumped core" */
+	if (try_to_debug ())
+	  break;
+	if (si->si_code != SI_USER && si->si_cyg)
+	  ((cygwin_exception *) si->si_cyg)->dumpstack ();
+	else
+	  {
+	    CONTEXT c;
+	    c.ContextFlags = CONTEXT_FULL;
+	    RtlCaptureContext (&c);
 #ifdef __x86_64__
-	   cygwin_exception exc ((PUINT_PTR) _my_tls.thread_context.rbp, &c);
+	    cygwin_exception exc ((PUINT_PTR) _my_tls.thread_context.rbp, &c);
 #else
-	   cygwin_exception exc ((PUINT_PTR) _my_tls.thread_context.ebp, &c);
+	    cygwin_exception exc ((PUINT_PTR) _my_tls.thread_context.ebp, &c);
 #endif
-	   exc.dumpstack ();
-	 }
-       break;
+	    exc.dumpstack ();
+	  }
+	break;
       }
 
   lock_process until_exit (true);
 
   if (have_execed || exit_state > ES_PROCESS_LOCKED)
-    myself.exit (sig);
+    {
+      debug_printf ("recursive exit?");
+      myself.exit (sig);
+    }
 
   /* Starve other threads in a vain attempt to stop them from doing something
      stupid. */