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* [glibc] support: Add support_mutex_pi_monotonic
@ 2021-10-01 13:21 Adhemerval Zanella
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From: Adhemerval Zanella @ 2021-10-01 13:21 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9cba3fa34b15017b269f2674ce7656bbc9d4d06d
commit 9cba3fa34b15017b269f2674ce7656bbc9d4d06d
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Wed Aug 11 18:16:51 2021 +0000
support: Add support_mutex_pi_monotonic
Returns true if Priority Inheritance support CLOCK_MONOTONIC.
Diff:
---
support/Makefile | 1 +
support/support_mutex_pi_monotonic.c | 36 ++++++++++++++++++++++++++++++++++++
support/xthread.h | 4 ++++
3 files changed, 41 insertions(+)
diff --git a/support/Makefile b/support/Makefile
index 2a0731796f..fd27c8451e 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -63,6 +63,7 @@ libsupport-routines = \
support_format_hostent \
support_format_netent \
support_isolate_in_subprocess \
+ support_mutex_pi_monotonic \
support_path_support_time64 \
support_process_state \
support_ptrace \
diff --git a/support/support_mutex_pi_monotonic.c b/support/support_mutex_pi_monotonic.c
new file mode 100644
index 0000000000..539b965243
--- /dev/null
+++ b/support/support_mutex_pi_monotonic.c
@@ -0,0 +1,36 @@
+/* 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
+support_mutex_pi_monotonic (void)
+{
+#ifdef __linux__
+# ifndef __NR_futex
+# define __NR_futex __NR_futex_time64
+# endif
+ 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..30501f5772 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 support_mutex_pi_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
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