Add Hurd-specific condition wait function

* Makefile (libpthread-routines): Add pt-hurd-cond-wait.
* Versions (libc): Add pthread_hurd_cond_wait_np.
(libpthread): Likewise.
* sysdeps/mach/hurd/bits/pthread-np.h: New file.
* sysdeps/mach/hurd/pt-hurd-cond-wait.c: Likewise.

2 files changed, 125 insertions, 0 deletions

diff --git a/sysdeps/mach/hurd/bits/pthread-np.h b/sysdeps/mach/hurd/bits/pthread-np.h
new file mode 100644
index 0000000..9817a06
--- /dev/null
+++ b/sysdeps/mach/hurd/bits/pthread-np.h
@@ -0,0 +1,32 @@
+/* Non-portable functions. Hurd on Mach version.
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/*
+ * Never include this file directly; use <pthread.h> or <cthreads.h> instead.
+ */
+
+#ifndef _BITS_PTHREAD_NP_H
+#define _BITS_PTHREAD_NP_H	1
+
+/* Same as pthread_cond_wait, but for Hurd-specific cancellation.
+   See hurd_thread_cancel.  */
+extern int pthread_hurd_cond_wait_np (pthread_cond_t *__restrict __cond,
+				      pthread_mutex_t *__restrict __mutex);
+
+#endif /* bits/pthread-np.h */
diff --git a/sysdeps/mach/hurd/pt-hurd-cond-wait.c b/sysdeps/mach/hurd/pt-hurd-cond-wait.c
new file mode 100644
index 0000000..d2b5847
--- /dev/null
+++ b/sysdeps/mach/hurd/pt-hurd-cond-wait.c
@@ -0,0 +1,93 @@
+/* pthread_hurd_cond_wait.  Hurd-specific wait on a condition.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <pthread.h>
+#include <assert.h>
+#include <hurd/signal.h>
+
+#include <pt-internal.h>
+
+int
+pthread_hurd_cond_wait_np (pthread_cond_t *cond, pthread_mutex_t *mutex)
+{
+  /* This function will be called by hurd_thread_cancel while we are blocked
+     We wake up all threads blocked on COND, so our thread will wake up and
+     notice the cancellation flag.  */
+  void cancel_me (void)
+    {
+      pthread_cond_broadcast (cond);
+    }
+  struct hurd_sigstate *ss = _hurd_self_sigstate ();
+  struct __pthread *self = _pthread_self ();
+  int cancel;
+
+  assert (ss->intr_port == MACH_PORT_NULL); /* Sanity check for signal bugs. */
+
+  /* Atomically enqueue our thread on the condition variable's queue of
+     waiters, and mark our sigstate to indicate that `cancel_me' must be
+     called to wake us up.  We must hold the sigstate lock while acquiring
+     the condition variable's lock and tweaking it, so that
+     hurd_thread_cancel can never suspend us and then deadlock in
+     pthread_cond_broadcast waiting for the condition variable's lock.  */
+
+  __spin_lock (&ss->lock);
+  __pthread_spin_lock (&cond->__lock);
+  cancel = ss->cancel;
+  if (cancel)
+    /* We were cancelled before doing anything.  Don't block at all.  */
+    ss->cancel = 0;
+  else
+    {
+      /* Put us on the queue so that pthread_cond_broadcast will know to wake
+         us up.  */
+      __pthread_enqueue (&cond->__queue, self);
+      /* Tell hurd_thread_cancel how to unblock us.  */
+      ss->cancel_hook = &cancel_me;
+    }
+  __pthread_spin_unlock (&cond->__lock);
+  __spin_unlock (&ss->lock);
+
+
+  if (cancel)
+    /* Cancelled on entry.  Just leave the mutex locked.  */
+    mutex = NULL;
+  else
+    {
+      /* Now unlock the mutex and block until woken.  */
+      __pthread_mutex_unlock (mutex);
+      __pthread_block (self);
+    }
+
+  __spin_lock (&ss->lock);
+  /* Clear the hook, now that we are done blocking.  */
+  ss->cancel_hook = NULL;
+  /* Check the cancellation flag; we might have unblocked due to
+     cancellation rather than a normal pthread_cond_signal or
+     pthread_cond_broadcast (or we might have just happened to get cancelled
+     right after waking up).  */
+  cancel |= ss->cancel;
+  ss->cancel = 0;
+  __spin_unlock (&ss->lock);
+
+  if (mutex)
+    /* Reacquire the mutex and return.  */
+    __pthread_mutex_lock (mutex);
+
+  return cancel;
+}