Prepare for radical source tree reorganization. zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 191 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/unix/sysv/linux/timer_routines.c b/REORG.TODO/sysdeps/unix/sysv/linux/timer_routines.c
new file mode 100644
index 0000000000..1d81304678
--- /dev/null
+++ b/REORG.TODO/sysdeps/unix/sysv/linux/timer_routines.c
@@ -0,0 +1,191 @@
+/* Copyright (C) 2003-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+   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; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <sysdep-cancel.h>
+#include <nptl/pthreadP.h>
+#include "kernel-posix-timers.h"
+
+
+/* List of active SIGEV_THREAD timers.  */
+struct timer *__active_timer_sigev_thread;
+/* Lock for the __active_timer_sigev_thread.  */
+pthread_mutex_t __active_timer_sigev_thread_lock = PTHREAD_MUTEX_INITIALIZER;
+
+
+struct thread_start_data
+{
+  void (*thrfunc) (sigval_t);
+  sigval_t sival;
+};
+
+
+/* Helper thread to call the user-provided function.  */
+static void *
+timer_sigev_thread (void *arg)
+{
+  /* The parent thread has all signals blocked.  This is a bit
+     surprising for user code, although valid.  We unblock all
+     signals.  */
+  sigset_t ss;
+  sigemptyset (&ss);
+  INTERNAL_SYSCALL_DECL (err);
+  INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, NULL, _NSIG / 8);
+
+  struct thread_start_data *td = (struct thread_start_data *) arg;
+
+  void (*thrfunc) (sigval_t) = td->thrfunc;
+  sigval_t sival = td->sival;
+
+  /* The TD object was allocated in timer_helper_thread.  */
+  free (td);
+
+  /* Call the user-provided function.  */
+  thrfunc (sival);
+
+  return NULL;
+}
+
+
+/* Helper function to support starting threads for SIGEV_THREAD.  */
+static void *
+timer_helper_thread (void *arg)
+{
+  /* Wait for the SIGTIMER signal, allowing the setXid signal, and
+     none else.  */
+  sigset_t ss;
+  sigemptyset (&ss);
+  __sigaddset (&ss, SIGTIMER);
+
+  /* Endless loop of waiting for signals.  The loop is only ended when
+     the thread is canceled.  */
+  while (1)
+    {
+      siginfo_t si;
+
+      /* sigwaitinfo cannot be used here, since it deletes
+	 SIGCANCEL == SIGTIMER from the set.  */
+
+      /* XXX The size argument hopefully will have to be changed to the
+	 real size of the user-level sigset_t.  */
+      int result = SYSCALL_CANCEL (rt_sigtimedwait, &ss, &si, NULL, _NSIG / 8);
+
+      if (result > 0)
+	{
+	  if (si.si_code == SI_TIMER)
+	    {
+	      struct timer *tk = (struct timer *) si.si_ptr;
+
+	      /* Check the timer is still used and will not go away
+		 while we are reading the values here.  */
+	      pthread_mutex_lock (&__active_timer_sigev_thread_lock);
+
+	      struct timer *runp = __active_timer_sigev_thread;
+	      while (runp != NULL)
+		if (runp == tk)
+		  break;
+		else
+		  runp = runp->next;
+
+	      if (runp != NULL)
+		{
+		  struct thread_start_data *td = malloc (sizeof (*td));
+
+		  /* There is not much we can do if the allocation fails.  */
+		  if (td != NULL)
+		    {
+		      /* This is the signal we are waiting for.  */
+		      td->thrfunc = tk->thrfunc;
+		      td->sival = tk->sival;
+
+		      pthread_t th;
+		      (void) pthread_create (&th, &tk->attr,
+					     timer_sigev_thread, td);
+		    }
+		}
+
+	      pthread_mutex_unlock (&__active_timer_sigev_thread_lock);
+	    }
+	  else if (si.si_code == SI_TKILL)
+	    /* The thread is canceled.  */
+	    pthread_exit (NULL);
+	}
+    }
+}
+
+
+/* Control variable for helper thread creation.  */
+pthread_once_t __helper_once attribute_hidden;
+
+
+/* TID of the helper thread.  */
+pid_t __helper_tid attribute_hidden;
+
+
+/* Reset variables so that after a fork a new helper thread gets started.  */
+static void
+reset_helper_control (void)
+{
+  __helper_once = PTHREAD_ONCE_INIT;
+  __helper_tid = 0;
+}
+
+
+void
+attribute_hidden
+__start_helper_thread (void)
+{
+  /* The helper thread needs only very little resources
+     and should go away automatically when canceled.  */
+  pthread_attr_t attr;
+  (void) pthread_attr_init (&attr);
+  (void) pthread_attr_setstacksize (&attr, __pthread_get_minstack (&attr));
+
+  /* Block all signals in the helper thread but SIGSETXID.  To do this
+     thoroughly we temporarily have to block all signals here.  The
+     helper can lose wakeups if SIGCANCEL is not blocked throughout,
+     but sigfillset omits it SIGSETXID.  So, we add SIGCANCEL back
+     explicitly here.  */
+  sigset_t ss;
+  sigset_t oss;
+  sigfillset (&ss);
+  __sigaddset (&ss, SIGCANCEL);
+  INTERNAL_SYSCALL_DECL (err);
+  INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, &oss, _NSIG / 8);
+
+  /* Create the helper thread for this timer.  */
+  pthread_t th;
+  int res = pthread_create (&th, &attr, timer_helper_thread, NULL);
+  if (res == 0)
+    /* We managed to start the helper thread.  */
+    __helper_tid = ((struct pthread *) th)->tid;
+
+  /* Restore the signal mask.  */
+  INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &oss, NULL,
+		    _NSIG / 8);
+
+  /* No need for the attribute anymore.  */
+  (void) pthread_attr_destroy (&attr);
+
+  /* We have to make sure that after fork()ing a new helper thread can
+     be created.  */
+  pthread_atfork (NULL, NULL, reset_helper_control);
+}