[PATCH 20/23] linux: Use 64-bit time_t syscall on clock_getcputclockid

[Adhemerval Zanella]

The syscall __NR_clock_getres_time64 (for 32-bit) or __NR_clock_getres
(for 64-bit) is used as default.  The 32-bit fallback is used iff
__ASSUME_TIME64_SYSCALLS is not defined, which assumes the kernel ABI
provides either __NR_rt_sigtimedwait (32-bit time_t).

Since the symbol does not use any type which might be affected by the
time_t, there is no need to add a 64-bit variant.

Checked on x86_64-linux-gnu and i686-linux-gnu (on 5.4 and on 4.15
kernel).
---
 sysdeps/unix/sysv/linux/clock_getcpuclockid.c | 37 ++++++++++++-------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/clock_getcpuclockid.c b/sysdeps/unix/sysv/linux/clock_getcpuclockid.c
index be1f477187..3c3bdd42ed 100644
--- a/sysdeps/unix/sysv/linux/clock_getcpuclockid.c
+++ b/sysdeps/unix/sysv/linux/clock_getcpuclockid.c
@@ -22,6 +22,20 @@
 #include "kernel-posix-cpu-timers.h"
 #include <shlib-compat.h>
 
+static int
+clock_getcpuclockid_return (int r, clockid_t pidclock, clockid_t *clock_id)
+{
+  if (r == 0)
+    {
+      *clock_id = pidclock;
+      return 0;
+    }
+  if (r == -EINVAL)
+    /* The clock_getres system call checked the PID for us.  */
+    return ESRCH;
+  return -r;
+}
+
 int
 __clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
 {
@@ -30,20 +44,17 @@ __clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
 
   const clockid_t pidclock = MAKE_PROCESS_CPUCLOCK (pid, CPUCLOCK_SCHED);
 
-  int r = INTERNAL_SYSCALL_CALL (clock_getres, pidclock, NULL);
-  if (!INTERNAL_SYSCALL_ERROR_P (r))
-    {
-      *clock_id = pidclock;
-      return 0;
-    }
+#ifndef __NR_clock_getres_time64
+# define __NR_clock_getres_time64 __NR_clock_getres
+#endif
+  int r = INTERNAL_SYSCALL_CALL (clock_getres_time64, pidclock, NULL);
+#ifndef __ASSUME_TIME64_SYSCALLS
+  if (r == 0 && r != -ENOSYS)
+    return clock_getcpuclockid_return (r, pidclock, clock_id);
 
-  if (INTERNAL_SYSCALL_ERRNO (r) == EINVAL)
-    {
-      /* The clock_getres system call checked the PID for us.  */
-      return ESRCH;
-    }
-  else
-    return INTERNAL_SYSCALL_ERRNO (r);
+  r = INTERNAL_SYSCALL_CALL (clock_getres, pidclock, NULL);
+#endif
+  return clock_getcpuclockid_return (r, pidclock, clock_id);
 }
 
 versioned_symbol (libc, __clock_getcpuclockid, clock_getcpuclockid, GLIBC_2_17);
-- 
2.25.1