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authorRoland McGrath <roland@hack.frob.com>2014-07-07 09:28:38 -0700
committerRoland McGrath <roland@hack.frob.com>2014-07-07 09:28:38 -0700
commit08192659bbeae149e7cb1f4c43547257f7099bb0 (patch)
tree9f602a4e9f0aefdb06bc15a76be46e958e91a58f /nptl/lowlevellock.c
parent96baf6ffc57b811bbc424a1fc72ef77dd56d7a18 (diff)
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Get rid of nptl/sysdeps/ entirely!
Diffstat (limited to 'nptl/lowlevellock.c')
-rw-r--r--nptl/lowlevellock.c124
1 files changed, 124 insertions, 0 deletions
diff --git a/nptl/lowlevellock.c b/nptl/lowlevellock.c
new file mode 100644
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+++ b/nptl/lowlevellock.c
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+/* low level locking for pthread library.  Generic futex-using version.
+   Copyright (C) 2003-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Paul Mackerras <paulus@au.ibm.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; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <lowlevellock.h>
+#include <sys/time.h>
+#include <atomic.h>
+
+void
+__lll_lock_wait_private (int *futex)
+{
+  if (*futex == 2)
+    lll_futex_wait (futex, 2, LLL_PRIVATE);
+
+  while (atomic_exchange_acq (futex, 2) != 0)
+    lll_futex_wait (futex, 2, LLL_PRIVATE);
+}
+
+
+/* These functions don't get included in libc.so  */
+#ifdef IS_IN_libpthread
+void
+__lll_lock_wait (int *futex, int private)
+{
+  if (*futex == 2)
+    lll_futex_wait (futex, 2, private);
+
+  while (atomic_exchange_acq (futex, 2) != 0)
+    lll_futex_wait (futex, 2, private);
+}
+
+
+int
+__lll_timedlock_wait (int *futex, const struct timespec *abstime, int private)
+{
+  /* Reject invalid timeouts.  */
+  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+    return EINVAL;
+
+  /* Try locking.  */
+  while (atomic_exchange_acq (futex, 2) != 0)
+    {
+      struct timeval tv;
+
+      /* Get the current time.  */
+      (void) __gettimeofday (&tv, NULL);
+
+      /* Compute relative timeout.  */
+      struct timespec rt;
+      rt.tv_sec = abstime->tv_sec - tv.tv_sec;
+      rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
+      if (rt.tv_nsec < 0)
+	{
+	  rt.tv_nsec += 1000000000;
+	  --rt.tv_sec;
+	}
+
+      if (rt.tv_sec < 0)
+	return ETIMEDOUT;
+
+      /* Wait.  */
+      lll_futex_timed_wait (futex, 2, &rt, private);
+    }
+
+  return 0;
+}
+
+
+int
+__lll_timedwait_tid (int *tidp, const struct timespec *abstime)
+{
+  int tid;
+
+  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+    return EINVAL;
+
+  /* Repeat until thread terminated.  */
+  while ((tid = *tidp) != 0)
+    {
+      struct timeval tv;
+      struct timespec rt;
+
+      /* Get the current time.  */
+      (void) __gettimeofday (&tv, NULL);
+
+      /* Compute relative timeout.  */
+      rt.tv_sec = abstime->tv_sec - tv.tv_sec;
+      rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
+      if (rt.tv_nsec < 0)
+	{
+	  rt.tv_nsec += 1000000000;
+	  --rt.tv_sec;
+	}
+
+      /* Already timed out?  */
+      if (rt.tv_sec < 0)
+	return ETIMEDOUT;
+
+      /* Wait until thread terminates.  The kernel so far does not use
+	 the private futex operations for this.  */
+      if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT)
+	return ETIMEDOUT;
+    }
+
+  return 0;
+}
+#endif