nptl: Use <unwind-link.h> for accessing the libgcc_s unwinder

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 15 insertions, 100 deletions

diff --git a/sysdeps/nptl/unwind-forcedunwind.c b/sysdeps/nptl/unwind-forcedunwind.c
index b70aae06ae..c0234670cf 100644
--- a/sysdeps/nptl/unwind-forcedunwind.c
+++ b/sysdeps/nptl/unwind-forcedunwind.c
@@ -16,134 +16,49 @@
    License along with the GNU C Library; see the file COPYING.LIB.  If
    not, see <https://www.gnu.org/licenses/>.  */
 
-#include <dlfcn.h>
 #include <stdio.h>
-#include <unwind.h>
+#include <unwind-link.h>
 #include <pthreadP.h>
 #include <sysdep.h>
 #include <gnu/lib-names.h>
 #include <unwind-resume.h>
 
-static void *libgcc_s_handle;
-void (*__libgcc_s_resume) (struct _Unwind_Exception *exc)
-  attribute_hidden __attribute__ ((noreturn));
-static _Unwind_Reason_Code (*libgcc_s_personality) PERSONALITY_PROTO;
-static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
-  (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
-static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
-
-void
-__attribute_noinline__
-pthread_cancel_init (void)
+struct unwind_link *
+__pthread_unwind_link_get (void)
 {
-  void *resume;
-  void *personality;
-  void *forcedunwind;
-  void *getcfa;
-  void *handle;
-
-  if (__glibc_likely (libgcc_s_handle != NULL))
-    {
-      /* Force gcc to reload all values.  */
-      asm volatile ("" ::: "memory");
-      return;
-    }
-
-  /* See include/dlfcn.h. Use of __libc_dlopen requires RTLD_NOW.  */
-  handle = __libc_dlopen (LIBGCC_S_SO);
-
-  if (handle == NULL
-      || (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
-      || (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL
-      || (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind"))
-	 == NULL
-      || (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL
-#ifdef ARCH_CANCEL_INIT
-      || ARCH_CANCEL_INIT (handle)
-#endif
-      )
-    __libc_fatal (LIBGCC_S_SO " must be installed for pthread_cancel to work\n");
-
-  PTR_MANGLE (resume);
-  __libgcc_s_resume = resume;
-  PTR_MANGLE (personality);
-  libgcc_s_personality = personality;
-  PTR_MANGLE (forcedunwind);
-  libgcc_s_forcedunwind = forcedunwind;
-  PTR_MANGLE (getcfa);
-  libgcc_s_getcfa = getcfa;
-  /* Make sure libgcc_s_handle is written last.  Otherwise,
-     pthread_cancel_init might return early even when the pointer the
-     caller is interested in is not initialized yet.  */
-  atomic_write_barrier ();
-  libgcc_s_handle = handle;
-}
-
-/* Register for cleanup in libpthread.so.  */
-void
-__nptl_unwind_freeres (void)
-{
-  void *handle = libgcc_s_handle;
-  if (handle != NULL)
-    {
-      libgcc_s_handle = NULL;
-      __libc_dlclose (handle);
-    }
+  struct unwind_link *unwind_link = __libc_unwind_link_get ();
+  if (unwind_link == NULL)
+    __libc_fatal (LIBGCC_S_SO
+		  " must be installed for pthread_cancel to work\n");
+  return unwind_link;
 }
 
 #if !HAVE_ARCH_UNWIND_RESUME
 void
 _Unwind_Resume (struct _Unwind_Exception *exc)
 {
-  if (__glibc_unlikely (libgcc_s_handle == NULL))
-    pthread_cancel_init ();
-  else
-    atomic_read_barrier ();
-
-  void (*resume) (struct _Unwind_Exception *exc) = __libgcc_s_resume;
-  PTR_DEMANGLE (resume);
-  resume (exc);
+  UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_Resume) (exc);
 }
 #endif
 
 _Unwind_Reason_Code
 __gcc_personality_v0 PERSONALITY_PROTO
 {
-  if (__glibc_unlikely (libgcc_s_handle == NULL))
-    pthread_cancel_init ();
-  else
-    atomic_read_barrier ();
-
-  __typeof (libgcc_s_personality) personality = libgcc_s_personality;
-  PTR_DEMANGLE (personality);
-  return (*personality) PERSONALITY_ARGS;
+  return UNWIND_LINK_PTR (__pthread_unwind_link_get (), personality)
+    PERSONALITY_ARGS;
 }
 
 _Unwind_Reason_Code
 _Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
 		      void *stop_argument)
 {
-  if (__glibc_unlikely (libgcc_s_handle == NULL))
-    pthread_cancel_init ();
-  else
-    atomic_read_barrier ();
-
-  _Unwind_Reason_Code (*forcedunwind)
-    (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *)
-    = libgcc_s_forcedunwind;
-  PTR_DEMANGLE (forcedunwind);
-  return forcedunwind (exc, stop, stop_argument);
+  return UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_ForcedUnwind)
+    (exc, stop, stop_argument);
 }
 
 _Unwind_Word
 _Unwind_GetCFA (struct _Unwind_Context *context)
 {
-  if (__glibc_unlikely (libgcc_s_handle == NULL))
-    pthread_cancel_init ();
-  else
-    atomic_read_barrier ();
-
-  _Unwind_Word (*getcfa) (struct _Unwind_Context *) = libgcc_s_getcfa;
-  PTR_DEMANGLE (getcfa);
-  return getcfa (context);
+  return UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_GetCFA)
+    (context);
 }