[hurd,commited] hurd: Rewrite __libc_cleanup_*

[Samuel Thibault <samuel dot thibault at ens-lyon dot org>]

From: Agustina Arzille <avarzille@riseup.net>

This makes it notably safe against 'return' and such, and used for
__libc_cleanup_push/pop.

	* sysdeps/mach/libc-lock.h (__libc_cleanup_frame): Define structure.
	(__libc_cleanup_fct): Define function.
	(__libc_cleanup_region_start, __libc_cleanup_region_end,
	__libc_cleanup_end): Rewrite implementation using
	__attribute__ ((__cleanup__)).
	(__libc_cleanup_push, __libc_cleanup_pop): New macros.
---
 ChangeLog                |  9 +++++++++
 sysdeps/mach/libc-lock.h | 47 ++++++++++++++++++++++++++++++-----------------
 2 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index c0074a6c3b..36430d6169 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2018-03-18  Agustina Arzille  <avarzille@riseup.net>
+
+	* sysdeps/mach/libc-lock.h (__libc_cleanup_frame): Define structure.
+	(__libc_cleanup_fct): Define function.
+	(__libc_cleanup_region_start, __libc_cleanup_region_end,
+	__libc_cleanup_end): Rewrite implementation using
+	__attribute__ ((__cleanup__)).
+	(__libc_cleanup_push, __libc_cleanup_pop): New macros.
+
 2018-03-18  Samuel Thibault  <samuel.thibault@ens-lyon.org>
 
 	* sysdeps/mach/hurd/cthreads.c: Include <cthreads.h>.
diff --git a/sysdeps/mach/libc-lock.h b/sysdeps/mach/libc-lock.h
index 89e5715341..1bb0235cf2 100644
--- a/sysdeps/mach/libc-lock.h
+++ b/sysdeps/mach/libc-lock.h
@@ -73,25 +73,38 @@ typedef cthread_key_t __libc_key_t;
 #define __libc_rwlock_trywrlock		__libc_lock_trylock
 #define __libc_rwlock_unlock		__libc_lock_unlock
 
-
-/* Start a critical region with a cleanup function */
-#define __libc_cleanup_region_start(DOIT, FCT, ARG)			    \
-{									    \
-  typeof (***(FCT)) *__save_FCT = (DOIT) ? (FCT) : 0;			    \
-  typeof (ARG) __save_ARG = ARG;					    \
-  /* close brace is in __libc_cleanup_region_end below. */
-
-/* End a critical region started with __libc_cleanup_region_start. */
-#define __libc_cleanup_region_end(DOIT)					    \
-  if ((DOIT) && __save_FCT != 0)					    \
-    (*__save_FCT)(__save_ARG);						    \
+struct __libc_cleanup_frame
+{
+  void (*__fct) (void *);
+  void *__argp;
+  int __doit;
+};
+
+__extern_inline void
+__libc_cleanup_fct (struct __libc_cleanup_frame *framep)
+{
+  if (framep->__doit)
+    framep->__fct (framep->__argp);
 }
 
-/* Sometimes we have to exit the block in the middle.  */
-#define __libc_cleanup_end(DOIT)					    \
-  if ((DOIT) && __save_FCT != 0)					    \
-    (*__save_FCT)(__save_ARG);						    \
-
+/* Start a critical region with a cleanup function */
+#define __libc_cleanup_region_start(DOIT, FCT, ARG)   \
+  do   \
+    {   \
+      struct __libc_cleanup_frame __cleanup   \
+        __attribute__ ((__cleanup__ (__libc_cleanup_fct))) =   \
+        { .__fct = (FCT), .__argp = (ARG), .__doit = (DOIT) };
+
+/* This one closes the brace above. */
+#define __libc_cleanup_region_end(DOIT)   \
+      __cleanup.__doit = (DOIT);   \
+    }   \
+  while (0)
+
+#define __libc_cleanup_end(DOIT)   __cleanup.__doit = (DOIT);
+
+#define __libc_cleanup_push(fct, arg) __libc_cleanup_region_start (1, fct, arg)
+#define __libc_cleanup_pop(execute) __libc_cleanup_region_end (execute)
 
 /* Use mutexes as once control variables. */
 
-- 
2.16.2