Port dumping better to WSL

Problem reported by Angelo Graziosi in:
http://lists.gnu.org/archive/html/emacs-devel/2016-12/msg00822.html
* src/sysdep.c (disable_address_randomization):
Detect buggy platforms where 'personality' always returns 0.

1 files changed, 9 insertions, 4 deletions

diff --git a/src/sysdep.c b/src/sysdep.c
index 96c9e538409..86d420f66c4 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -144,11 +144,16 @@ static const int baud_convert[] =
 bool
 disable_address_randomization (void)
 {
-  bool disabled = false;
   int pers = personality (0xffffffff);
-  disabled = (! (pers & ADDR_NO_RANDOMIZE)
-              && 0 <= personality (pers | ADDR_NO_RANDOMIZE));
-  return disabled;
+  if (pers < 0)
+    return false;
+  int desired_pers = pers | ADDR_NO_RANDOMIZE;
+
+  /* Call 'personality' twice, to detect buggy platforms like WSL
+     where 'personality' always returns 0.  */
+  return (pers != desired_pers
+          && personality (desired_pers) == pers
+          && personality (0xffffffff) == desired_pers);
 }
 #endif