* cygtls.cc (_cygtls::init_exception_handler): Revert patch

        from 2005-12-02.
        * exceptions.cc (stack_info::walk): Add workaround for NT 5.2
        64 bit OSes.
        * wincap.h (wincaps::has_restricted_stack_args): New element.
        * wincap.cc: Implement above element throughout.
        (wincapc::init): Reset has_restricted_stack_args if not running
        under WOW64.

1 files changed, 14 insertions, 3 deletions

diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index fc361b59b..05cc91696 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -245,9 +245,20 @@ stack_info::walk ()
   sf.AddrReturn.Offset = (DWORD) *++ebp;
 
   if (needargs)
-    /* The arguments follow the return address */
-    for (unsigned i = 0; i < NPARAMS; i++)
-      sf.Params[i] = (DWORD) *++ebp;
+    {
+      unsigned nparams = NPARAMS;
+
+      /* The arguments follow the return address */
+      sf.Params[0] = (DWORD) *++ebp;
+      /* Hack for XP/2K3 WOW64.  If the first stack param points to the
+	 application entry point, we can only fetch one additional
+	 parameter.  Accessing anything beyond this address results in
+	 a SEGV.  This is fixed in Vista/2K8 WOW64. */
+      if (wincap.has_restricted_stack_args () && sf.Params[0] == 0x401000)
+	nparams = 2;
+      for (unsigned i = 0; i < nparams; i++)
+	sf.Params[i] = (DWORD) *++ebp;
+    }
 
   return 1;
 }