sysdeps/clock_gettime: Use clock_gettime64 if avaliable

With the clock_gettime64 call we prefer to use vDSO. There is no call
to clock_gettime64 on glibc with older headers and kernel 5.1+ if it
doesn't support vDSO.

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

1 files changed, 43 insertions, 1 deletions

diff --git a/sysdeps/unix/sysv/linux/clock_gettime.c b/sysdeps/unix/sysv/linux/clock_gettime.c
index ca40983f6c..875c4fe905 100644
--- a/sysdeps/unix/sysv/linux/clock_gettime.c
+++ b/sysdeps/unix/sysv/linux/clock_gettime.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <sysdep.h>
+#include <kernel-features.h>
 #include <errno.h>
 #include <time.h>
 #include "kernel-posix-cpu-timers.h"
@@ -30,10 +31,51 @@
 
 /* Get current value of CLOCK and store it in TP.  */
 int
+__clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp)
+{
+#ifdef __ASSUME_TIME64_SYSCALLS
+# ifndef __NR_clock_gettime64
+#  define __NR_clock_gettime64   __NR_clock_gettime
+#  define __vdso_clock_gettime64 __vdso_clock_gettime
+# endif
+   return INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
+#else
+# if defined HAVE_CLOCK_GETTIME64_VSYSCALL
+  int ret64 = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
+  if (ret64 == 0 || errno != ENOSYS)
+    return ret64;
+# endif
+  struct timespec tp32;
+  int ret = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &tp32);
+  if (ret == 0)
+    *tp = valid_timespec_to_timespec64 (tp32);
+  return ret;
+#endif
+}
+
+#if __TIMESIZE != 64
+int
 __clock_gettime (clockid_t clock_id, struct timespec *tp)
 {
-  return INLINE_VSYSCALL (clock_gettime, 2, clock_id, tp);
+  int ret;
+  struct __timespec64 tp64;
+
+  ret = __clock_gettime64 (clock_id, &tp64);
+
+  if (ret == 0)
+    {
+      if (! in_time_t_range (tp64.tv_sec))
+        {
+          __set_errno (EOVERFLOW);
+          return -1;
+        }
+
+      *tp = valid_timespec64_to_timespec (tp64);
+    }
+
+  return ret;
 }
+#endif
 libc_hidden_def (__clock_gettime)
 
 versioned_symbol (libc, __clock_gettime, clock_gettime, GLIBC_2_17);