nptl: Add POSIX-proposed pthread_cond_clockwait

Add:

 int pthread_cond_clockwait (pthread_cond_t *cond,
                             pthread_mutex_t *mutex,
                             clockid_t clockid,
                             const struct timespec *abstime)

which behaves just like pthread_cond_timedwait except it always measures
abstime against the supplied clockid. Currently supports CLOCK_REALTIME
and
CLOCK_MONOTONIC and returns EINVAL if any other clock is specified.

Includes feedback from many others. This function was originally
proposed[1] as pthread_cond_timedwaitonclock_np, but The Austin Group
preferred the new name.

	* nptl/Makefile: Add tst-cond26 and tst-cond27
	* nptl/Versions (GLIBC_2.30): Add pthread_cond_clockwait
	* sysdeps/nptl/pthread.h: Likewise
	* nptl/forward.c: Add __pthread_cond_clockwait
	* nptl/forward.c: Likewise
	* nptl/pthreadP.h: Likewise
	* sysdeps/nptl/pthread-functions.h: Likewise
	* nptl/pthread_cond_wait.c (__pthread_cond_wait_common): Add
	clockid parameter and comment describing why we don't need to
	check
	its value. Use that value when calling
	futex_abstimed_wait_cancelable rather than reading the clock
	from
	the flags. (__pthread_cond_wait): Pass unused clockid parameter.
	(__pthread_cond_timedwait): Read clock from flags and pass it to
	__pthread_cond_wait_common. (__pthread_cond_clockwait): Add new
	function with weak alias from pthread_cond_clockwait.
	* sysdeps/mach/hurd/i386/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/aarch64/libpthread.abilist
	* (GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/alpha/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/arm/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/csky/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/hppa/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/i386/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/ia64/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/nios2/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/riscv/rv64/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/sh/libpthread.abilist (GLIBC_2.30):
	* Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libpthread.abilist
	(GLIBC_2.30): Likewise.
	* nptl/tst-cond11.c (run_test): Support testing
	pthread_cond_clockwait too by using a special magic
	CLOCK_USE_ATTR_CLOCK value to determine whether to call
	pthread_cond_timedwait or pthread_cond_clockwait. (do_test):
	Pass
	CLOCK_USE_ATTR_CLOCK for existing tests, and add new tests using
	all combinations of CLOCK_MONOTONIC and CLOCK_REALTIME.
	* ntpl/tst-cond26.c: New test for passing unsupported and
	* invalid
	clocks to pthread_cond_clockwait.
	* nptl/tst-cond27.c: Add test similar to tst-cond5.c, but using
	struct timespec and pthread_cond_clockwait.
	* manual/threads.texi: Document pthread_cond_clockwait. The
	* comment
	was provided by Carlos O'Donell.

[1] https://sourceware.org/ml/libc-alpha/2015-07/msg00193.html

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

9 files changed, 221 insertions, 18 deletions

diff --git a/nptl/Makefile b/nptl/Makefile
index fefdeb3..76bfd89 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -251,6 +251,7 @@ tests = tst-attr1 tst-attr2 tst-attr3 tst-default-attr \
 	tst-cond8 tst-cond9 tst-cond10 tst-cond11 tst-cond12 tst-cond13 \
 	tst-cond14 tst-cond15 tst-cond16 tst-cond17 tst-cond18 tst-cond19 \
 	tst-cond20 tst-cond21 tst-cond22 tst-cond23 tst-cond24 tst-cond25 \
+	tst-cond26 tst-cond27 \
 	tst-cond-except \
 	tst-robust1 tst-robust2 tst-robust3 tst-robust4 tst-robust5 \
 	tst-robust6 tst-robust7 tst-robust8 tst-robust9 \
diff --git a/nptl/Versions b/nptl/Versions
index 4f0e837..3ab0ae5 100644
--- a/nptl/Versions
+++ b/nptl/Versions
@@ -277,7 +277,7 @@ libpthread {
   }
 
   GLIBC_2.30 {
-    sem_clockwait;
+    sem_clockwait; pthread_cond_clockwait;
   }
 
   GLIBC_PRIVATE {
diff --git a/nptl/forward.c b/nptl/forward.c
index ed1e7d0..50f358f 100644
--- a/nptl/forward.c
+++ b/nptl/forward.c
@@ -164,6 +164,11 @@ FORWARD (__pthread_cond_timedwait,
 	  const struct timespec *abstime), (cond, mutex, abstime), 0)
 versioned_symbol (libc, __pthread_cond_timedwait, pthread_cond_timedwait,
 		  GLIBC_2_3_2);
+FORWARD (__pthread_cond_clockwait,
+	 (pthread_cond_t *cond, pthread_mutex_t *mutex, clockid_t clockid,
+	  const struct timespec *abstime), (cond, mutex, clockid, abstime),
+	 0)
+weak_alias (__pthread_cond_clockwait, pthread_cond_clockwait);
 
 
 FORWARD (pthread_equal, (pthread_t thread1, pthread_t thread2),
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 73935f8..9c2a3d7 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -95,6 +95,7 @@ static const struct pthread_functions pthread_functions =
     .ptr___pthread_cond_signal = __pthread_cond_signal,
     .ptr___pthread_cond_wait = __pthread_cond_wait,
     .ptr___pthread_cond_timedwait = __pthread_cond_timedwait,
+    .ptr___pthread_cond_clockwait = __pthread_cond_clockwait,
 # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2)
     .ptr___pthread_cond_broadcast_2_0 = __pthread_cond_broadcast_2_0,
     .ptr___pthread_cond_destroy_2_0 = __pthread_cond_destroy_2_0,
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index 66527d8..d80662a 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -449,6 +449,11 @@ extern int __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex);
 extern int __pthread_cond_timedwait (pthread_cond_t *cond,
 				     pthread_mutex_t *mutex,
 				     const struct timespec *abstime);
+extern int __pthread_cond_clockwait (pthread_cond_t *cond,
+				     pthread_mutex_t *mutex,
+				     clockid_t clockid,
+				     const struct timespec *abstime)
+  __nonnull ((1, 2, 4));
 extern int __pthread_condattr_destroy (pthread_condattr_t *attr);
 extern int __pthread_condattr_init (pthread_condattr_t *attr);
 extern int __pthread_key_create (pthread_key_t *key, void (*destr) (void *));
diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
index 7385562..558f930 100644
--- a/nptl/pthread_cond_wait.c
+++ b/nptl/pthread_cond_wait.c
@@ -378,6 +378,7 @@ __condvar_cleanup_waiting (void *arg)
 */
 static __always_inline int
 __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
+    clockid_t clockid,
     const struct timespec *abstime)
 {
   const int maxspin = 0;
@@ -386,6 +387,11 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
 
   LIBC_PROBE (cond_wait, 2, cond, mutex);
 
+  /* clockid will already have been checked by
+     __pthread_cond_clockwait or pthread_condattr_setclock, or we
+     don't use it if abstime is NULL, so we don't need to check it
+     here. */
+
   /* Acquire a position (SEQ) in the waiter sequence (WSEQ).  We use an
      atomic operation because signals and broadcasts may update the group
      switch without acquiring the mutex.  We do not need release MO here
@@ -511,10 +517,6 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
 	        err = ETIMEDOUT;
 	      else
 		{
-		  const clockid_t clockid =
-		    ((flags & __PTHREAD_COND_CLOCK_MONOTONIC_MASK) != 0) ?
-		    CLOCK_MONOTONIC : CLOCK_REALTIME;
-
 		  err = futex_abstimed_wait_cancelable
                     (cond->__data.__g_signals + g, 0, clockid, abstime,
                      private);
@@ -632,7 +634,8 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
 int
 __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
 {
-  return __pthread_cond_wait_common (cond, mutex, NULL);
+  /* clockid is unused when abstime is NULL. */
+  return __pthread_cond_wait_common (cond, mutex, 0, NULL);
 }
 
 /* See __pthread_cond_wait_common.  */
@@ -644,10 +647,39 @@ __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
      it can assume that abstime is not NULL.  */
   if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
     return EINVAL;
-  return __pthread_cond_wait_common (cond, mutex, abstime);
+
+  /* Relaxed MO is suffice because clock ID bit is only modified
+     in condition creation.  */
+  unsigned int flags = atomic_load_relaxed (&cond->__data.__wrefs);
+  clockid_t clockid = (flags & __PTHREAD_COND_CLOCK_MONOTONIC_MASK)
+                    ? CLOCK_MONOTONIC : CLOCK_REALTIME;
+  return __pthread_cond_wait_common (cond, mutex, clockid, abstime);
+}
+
+/* See __pthread_cond_wait_common.  */
+int
+__pthread_cond_clockwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
+			  clockid_t clockid,
+			  const struct timespec *abstime)
+{
+  /* Check parameter validity.  This should also tell the compiler that
+     it can assume that abstime is not NULL.  */
+  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+    return EINVAL;
+
+  if (!futex_abstimed_supported_clockid (clockid))
+    return EINVAL;
+
+  /* If we do not support waiting using CLOCK_MONOTONIC, return an error.  */
+  if (clockid == CLOCK_MONOTONIC
+      && !futex_supports_exact_relative_timeouts ())
+    return EINVAL;
+
+  return __pthread_cond_wait_common (cond, mutex, clockid, abstime);
 }
 
 versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
 		  GLIBC_2_3_2);
 versioned_symbol (libpthread, __pthread_cond_timedwait, pthread_cond_timedwait,
 		  GLIBC_2_3_2);
+weak_alias (__pthread_cond_clockwait, pthread_cond_clockwait);
diff --git a/nptl/tst-cond11.c b/nptl/tst-cond11.c
index 3bc4ff4..6ce95aa 100644
--- a/nptl/tst-cond11.c
+++ b/nptl/tst-cond11.c
@@ -22,28 +22,32 @@
 #include <time.h>
 #include <unistd.h>
 #include <support/check.h>
+#include <support/test-driver.h>
 #include <support/timespec.h>
 #include <support/xthread.h>
 #include <support/xtime.h>
 
+/* A bogus clock value that tells run_test to use pthread_cond_timedwait
+   rather than pthread_condclockwait.  */
+#define CLOCK_USE_ATTR_CLOCK (-1)
 
 #if defined _POSIX_CLOCK_SELECTION && _POSIX_CLOCK_SELECTION >= 0
 static int
-run_test (clockid_t cl)
+run_test (clockid_t attr_clock, clockid_t wait_clock)
 {
   pthread_condattr_t condattr;
   pthread_cond_t cond;
   pthread_mutexattr_t mutattr;
   pthread_mutex_t mut;
 
-  printf ("clock = %d\n", (int) cl);
+  verbose_printf ("attr_clock = %d\n", (int) attr_clock);
 
   TEST_COMPARE (pthread_condattr_init (&condattr), 0);
-  TEST_COMPARE (pthread_condattr_setclock (&condattr, cl), 0);
+  TEST_COMPARE (pthread_condattr_setclock (&condattr, attr_clock), 0);
 
-  clockid_t cl2;
-  TEST_COMPARE (pthread_condattr_getclock (&condattr, &cl2), 0);
-  TEST_COMPARE (cl, cl2);
+  clockid_t attr_clock_read;
+  TEST_COMPARE (pthread_condattr_getclock (&condattr, &attr_clock_read), 0);
+  TEST_COMPARE (attr_clock, attr_clock_read);
 
   TEST_COMPARE (pthread_cond_init (&cond, &condattr), 0);
   TEST_COMPARE (pthread_condattr_destroy (&condattr), 0);
@@ -57,13 +61,20 @@ run_test (clockid_t cl)
   TEST_COMPARE (pthread_mutex_lock (&mut), EDEADLK);
 
   struct timespec ts_timeout;
-  xclock_gettime (cl, &ts_timeout);
+  xclock_gettime (wait_clock == CLOCK_USE_ATTR_CLOCK ? attr_clock : wait_clock,
+                  &ts_timeout);
 
   /* Wait one second.  */
   ++ts_timeout.tv_sec;
 
-  TEST_COMPARE (pthread_cond_timedwait (&cond, &mut, &ts_timeout), ETIMEDOUT);
-  TEST_TIMESPEC_BEFORE_NOW (ts_timeout, cl);
+  if (wait_clock == CLOCK_USE_ATTR_CLOCK) {
+    TEST_COMPARE (pthread_cond_timedwait (&cond, &mut, &ts_timeout), ETIMEDOUT);
+    TEST_TIMESPEC_BEFORE_NOW (ts_timeout, attr_clock);
+  } else {
+    TEST_COMPARE (pthread_cond_clockwait (&cond, &mut, wait_clock, &ts_timeout),
+                  ETIMEDOUT);
+    TEST_TIMESPEC_BEFORE_NOW (ts_timeout, wait_clock);
+  }
 
   xpthread_mutex_unlock (&mut);
   xpthread_mutex_destroy (&mut);
@@ -83,7 +94,7 @@ do_test (void)
 
 #else
 
-  run_test (CLOCK_REALTIME);
+  run_test (CLOCK_REALTIME, CLOCK_USE_ATTR_CLOCK);
 
 # if defined _POSIX_MONOTONIC_CLOCK && _POSIX_MONOTONIC_CLOCK >= 0
 #  if _POSIX_MONOTONIC_CLOCK == 0
@@ -93,8 +104,13 @@ do_test (void)
   else if (e == 0)
       FAIL_RET ("sysconf (_SC_MONOTONIC_CLOCK) must not return 0");
   else
+    {
 #  endif
-    run_test (CLOCK_MONOTONIC);
+      run_test (CLOCK_MONOTONIC, CLOCK_USE_ATTR_CLOCK);
+      run_test (CLOCK_REALTIME, CLOCK_MONOTONIC);
+      run_test (CLOCK_MONOTONIC, CLOCK_MONOTONIC);
+      run_test (CLOCK_MONOTONIC, CLOCK_REALTIME);
+    }
 # else
   puts ("_POSIX_MONOTONIC_CLOCK not defined");
 # endif
diff --git a/nptl/tst-cond26.c b/nptl/tst-cond26.c
new file mode 100644
index 0000000..bb4d6c9
--- /dev/null
+++ b/nptl/tst-cond26.c
@@ -0,0 +1,77 @@
+/* Test unsupported/bad clocks passed to pthread_cond_clockwait.
+
+   Copyright (C) 2019 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 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 <pthread.h>
+#include <stdio.h>
+#include <time.h>
+#include <unistd.h>
+#include <support/check.h>
+#include <support/timespec.h>
+#include <support/xthread.h>
+
+static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+static pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER;
+
+#define NOT_A_VALID_CLOCK 123456
+
+static int
+do_test (void)
+{
+  xpthread_mutex_lock (&mut);
+
+  const struct timespec ts = make_timespec (0, 0);
+
+  /* These clocks are meaningless to sem_clockwait.  */
+#if defined(CLOCK_PROCESS_CPUTIME_ID)
+  TEST_COMPARE (pthread_cond_clockwait (&cond, &mut,
+                                        CLOCK_PROCESS_CPUTIME_ID, &ts), EINVAL);
+#endif
+#if defined(CLOCK_THREAD_CPUTIME_ID)
+  TEST_COMPARE (pthread_cond_clockwait (&cond, &mut,
+                                        CLOCK_THREAD_CPUTIME_ID, &ts), EINVAL);
+#endif
+
+  /* These clocks might be meaningful, but are currently unsupported
+     by pthread_cond_clockwait.  */
+#if defined(CLOCK_REALTIME_COARSE)
+  TEST_COMPARE (pthread_cond_clockwait (&cond, &mut,
+                                        CLOCK_REALTIME_COARSE, &ts), EINVAL);
+#endif
+#if defined(CLOCK_MONOTONIC_RAW)
+  TEST_COMPARE (pthread_cond_clockwait (&cond, &mut,
+                                        CLOCK_MONOTONIC_RAW, &ts), EINVAL);
+#endif
+#if defined(CLOCK_MONOTONIC_COARSE)
+  TEST_COMPARE (pthread_cond_clockwait (&cond, &mut,
+                                        CLOCK_MONOTONIC_COARSE, &ts), EINVAL);
+#endif
+#if defined(CLOCK_BOOTTIME)
+  TEST_COMPARE (pthread_cond_clockwait (&cond, &mut,
+                                        CLOCK_BOOTTIME, &ts), EINVAL);
+#endif
+
+  /* This is a completely invalid clock.  */
+  TEST_COMPARE (pthread_cond_clockwait (&cond, &mut,
+                                        NOT_A_VALID_CLOCK, &ts), EINVAL);
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/nptl/tst-cond27.c b/nptl/tst-cond27.c
new file mode 100644
index 0000000..ad9658a
--- /dev/null
+++ b/nptl/tst-cond27.c
@@ -0,0 +1,66 @@
+/* Test pthread_cond_clockwait timeout.
+
+   Copyright (C) 2019 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 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 <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <sys/time.h>
+#include <support/check.h>
+#include <support/timespec.h>
+#include <support/xthread.h>
+
+
+static pthread_mutex_t mut = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP;
+static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+
+
+static int
+do_test_clock (clockid_t clockid)
+{
+  /* Get the mutex.  */
+  xpthread_mutex_lock (&mut);
+
+  /* Waiting for the condition will fail.  But we want the timeout here.  */
+  const struct timespec ts_now = xclock_now (clockid);
+  const struct timespec ts_timeout =
+    timespec_add (ts_now, make_timespec (0, 500000000));
+
+  /* In theory pthread_cond_clockwait could return zero here due to
+     spurious wakeup. However that can't happen without a signal or an
+     additional waiter.  */
+  TEST_COMPARE (pthread_cond_clockwait (&cond, &mut, clockid, &ts_timeout),
+                ETIMEDOUT);
+
+  xpthread_mutex_unlock (&mut);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  do_test_clock (CLOCK_MONOTONIC);
+  do_test_clock (CLOCK_REALTIME);
+  return 0;
+}
+
+#include <support/test-driver.c>