posix: Consolidate register-atfork

Both htl and nptl uses a different data structure to implement atfork
handlers.  The nptl one was refactored by 27761a1042d to use a dynarray
which simplifies the code.

This patch moves the nptl one to be the generic implementation and
replace Hurd linked one.  Different than previous NPTL, Hurd also uses
a global lock, so performance should be similar.

Checked on x86_64-linux-gnu, i686-linux-gnu, and with a build for
i686-gnu.

2 files changed, 0 insertions, 151 deletions

diff --git a/nptl/Makefile b/nptl/Makefile
index 33766eaf7a..e5d69e8858 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -74,7 +74,6 @@ routines = \
   pthread_self \
   pthread_setschedparam \
   pthread_sigmask \
-  register-atfork \
 
 shared-only-routines = forward
 static-only-routines = pthread_atfork
diff --git a/nptl/register-atfork.c b/nptl/register-atfork.c
deleted file mode 100644
index 30c16fba40..0000000000
--- a/nptl/register-atfork.c
+++ /dev/null
@@ -1,150 +0,0 @@
-/* Copyright (C) 2002-2021 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <errno.h>
-#include <stdlib.h>
-#include <string.h>
-#include <fork.h>
-#include <atomic.h>
-
-#define DYNARRAY_ELEMENT           struct fork_handler
-#define DYNARRAY_STRUCT            fork_handler_list
-#define DYNARRAY_PREFIX            fork_handler_list_
-#define DYNARRAY_INITIAL_SIZE      48
-#include <malloc/dynarray-skeleton.c>
-
-static struct fork_handler_list fork_handlers;
-static bool fork_handler_init = false;
-
-static int atfork_lock = LLL_LOCK_INITIALIZER;
-
-int
-__register_atfork (void (*prepare) (void), void (*parent) (void),
-		   void (*child) (void), void *dso_handle)
-{
-  lll_lock (atfork_lock, LLL_PRIVATE);
-
-  if (!fork_handler_init)
-    {
-      fork_handler_list_init (&fork_handlers);
-      fork_handler_init = true;
-    }
-
-  struct fork_handler *newp = fork_handler_list_emplace (&fork_handlers);
-  if (newp != NULL)
-    {
-      newp->prepare_handler = prepare;
-      newp->parent_handler = parent;
-      newp->child_handler = child;
-      newp->dso_handle = dso_handle;
-    }
-
-  /* Release the lock.  */
-  lll_unlock (atfork_lock, LLL_PRIVATE);
-
-  return newp == NULL ? ENOMEM : 0;
-}
-libc_hidden_def (__register_atfork)
-
-static struct fork_handler *
-fork_handler_list_find (struct fork_handler_list *fork_handlers,
-			void *dso_handle)
-{
-  for (size_t i = 0; i < fork_handler_list_size (fork_handlers); i++)
-    {
-      struct fork_handler *elem = fork_handler_list_at (fork_handlers, i);
-      if (elem->dso_handle == dso_handle)
-	return elem;
-    }
-  return NULL;
-}
-
-void
-__unregister_atfork (void *dso_handle)
-{
-  lll_lock (atfork_lock, LLL_PRIVATE);
-
-  struct fork_handler *first = fork_handler_list_find (&fork_handlers,
-						       dso_handle);
-  /* Removing is done by shifting the elements in the way the elements
-     that are not to be removed appear in the beginning in dynarray.
-     This avoid the quadradic run-time if a naive strategy to remove and
-     shift one element at time.  */
-  if (first != NULL)
-    {
-      struct fork_handler *new_end = first;
-      first++;
-      for (; first != fork_handler_list_end (&fork_handlers); ++first)
-	{
-	  if (first->dso_handle != dso_handle)
-	    {
-	      *new_end = *first;
-	      ++new_end;
-	    }
-	}
-
-      ptrdiff_t removed = first - new_end;
-      for (size_t i = 0; i < removed; i++)
-	fork_handler_list_remove_last (&fork_handlers);
-    }
-
-  lll_unlock (atfork_lock, LLL_PRIVATE);
-}
-
-void
-__run_fork_handlers (enum __run_fork_handler_type who, _Bool do_locking)
-{
-  struct fork_handler *runp;
-
-  if (who == atfork_run_prepare)
-    {
-      if (do_locking)
-	lll_lock (atfork_lock, LLL_PRIVATE);
-      size_t sl = fork_handler_list_size (&fork_handlers);
-      for (size_t i = sl; i > 0; i--)
-	{
-	  runp = fork_handler_list_at (&fork_handlers, i - 1);
-	  if (runp->prepare_handler != NULL)
-	    runp->prepare_handler ();
-	}
-    }
-  else
-    {
-      size_t sl = fork_handler_list_size (&fork_handlers);
-      for (size_t i = 0; i < sl; i++)
-	{
-	  runp = fork_handler_list_at (&fork_handlers, i);
-	  if (who == atfork_run_child && runp->child_handler)
-	    runp->child_handler ();
-	  else if (who == atfork_run_parent && runp->parent_handler)
-	    runp->parent_handler ();
-	}
-      if (do_locking)
-	lll_unlock (atfork_lock, LLL_PRIVATE);
-    }
-}
-
-
-libc_freeres_fn (free_mem)
-{
-  lll_lock (atfork_lock, LLL_PRIVATE);
-
-  fork_handler_list_free (&fork_handlers);
-
-  lll_unlock (atfork_lock, LLL_PRIVATE);
-}