diff mbox series

[3/4] support: Add xpthread_mutex_pi_support_monotonic

Message ID 20210811200133.3869287-4-adhemerval.zanella@linaro.org
State Superseded
Headers
Series Add CLOCK_MONOTONIC support for PI mutexes |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Adhemerval Zanella Netto Aug. 11, 2021, 8:01 p.m. UTC 
  Returns true if Priority Inheritance support CLOCK_MONOTONIC.
---
 support/Makefile                              |  1 +
 support/xpthread_mutex_pi_support_monotonic.c | 33 +++++++++++++++++++
 support/xthread.h                             |  4 +++
 3 files changed, 38 insertions(+)
 create mode 100644 support/xpthread_mutex_pi_support_monotonic.c

Comments

Florian Weimer Aug. 16, 2021, 8:01 a.m. UTC | #1 
* Adhemerval Zanella via Libc-alpha:

> Returns true if Priority Inheritance support CLOCK_MONOTONIC.

In the past, we used support_* interfaces for general checking of system
properties.  The x* interfaces are thin wrappers around glibc functions
that terminate the process upon error.

Thanks,
Florian
Adhemerval Zanella Netto Aug. 19, 2021, 12:49 p.m. UTC | #2 
On 16/08/2021 05:01, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
> 
>> Returns true if Priority Inheritance support CLOCK_MONOTONIC.
> 
> In the past, we used support_* interfaces for general checking of system
> properties.  The x* interfaces are thin wrappers around glibc functions
> that terminate the process upon error.
> 
> Thanks,
> Florian
> 

Fair enough, I will change it.
diff mbox series

Patch

diff --git a/support/Makefile b/support/Makefile
index a462781718..6360e86646 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -179,6 +179,7 @@  libsupport-routines = \
   xpthread_sigmask \
   xpthread_spin_lock \
   xpthread_spin_unlock \
+  xpthread_mutex_pi_support_monotonic \
   xraise \
   xreadlink \
   xrealloc \
diff --git a/support/xpthread_mutex_pi_support_monotonic.c b/support/xpthread_mutex_pi_support_monotonic.c
new file mode 100644
index 0000000000..eb42622913
--- /dev/null
+++ b/support/xpthread_mutex_pi_support_monotonic.c
@@ -0,0 +1,33 @@ 
+/* Returns whether Priority Inheritance support CLOCK_MONOTONIC.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/xthread.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+bool
+xpthread_mutex_pi_support_monotonic (void)
+{
+#ifdef __linux__
+  int r = syscall (__NR_futex, &(unsigned int){0}, 13 /* FUTEX_LOCK_PI2  */,
+		   0, NULL);
+  return r == 0;
+#else
+  return false;
+#endif
+}
diff --git a/support/xthread.h b/support/xthread.h
index a4a4ec5b1e..7074720bd9 100644
--- a/support/xthread.h
+++ b/support/xthread.h
@@ -21,6 +21,7 @@ 
 
 #include <pthread.h>
 #include <sys/cdefs.h>
+#include <stdbool.h>
 
 __BEGIN_DECLS
 
@@ -29,6 +30,9 @@  __BEGIN_DECLS
    exit function, so atexit handlers are executed.  */
 void delayed_exit (int seconds);
 
+/* Returns true if Priority Inheritance support CLOCK_MONOTONIC.  */
+bool xpthread_mutex_pi_support_monotonic (void);
+
 /* Terminate the process (with exit status 1) if VALUE is not zero.
    In that case, print a failure message to standard output mentioning
    FUNCTION.  The process is terminated with the exit function, so