[PATCH v6 1/3] sysdeps/clock_nanosleep: Use clock_nanosleep_time64 if avaliable

[Alistair Francis <alistair dot francis at wdc dot com>]

The clock_nanosleep syscall is not supported on newer 32-bit platforms (such
as RV32). To fix this issue let's use clock_nanosleep_time64 if it is
avaliable.
---
This patch was runtime tested with RV32 and RV64
It was build tested using the ./scripts/build-many-glibcs.py script.

I also ran:
$ make ; make install ; make check
tests on native ARM (32-bit) with the following three confiugrations:
 - 4.19 Kernel and 4.19 Headers
 - 5.2 Kernel and 4.19 Headers
 - 5.2 Kernel and 5.2 Headers
and didn't see any regressions

v6:
 - Split header changes into seperate patches
 - Don't check for ENOSYS in the incorrect places
 - Don't change indendtation of file
v5:
 - Fix clock_nanosleep syscall
 - Rebase on master

v4:
 - Rebase on master
 - Use __clock_nanosleep to avoid duplicate implementations
 - Fix the error handling when a syscall fails
v2:
 - Explicitly include `#include <kernel-features.h>`

 include/time.h                            |  8 +++
 sysdeps/unix/sysv/linux/clock_nanosleep.c | 61 +++++++++++++++++++++--
 2 files changed, 65 insertions(+), 4 deletions(-)

diff --git a/include/time.h b/include/time.h
index b3e635395db..d7800eb30f8 100644
--- a/include/time.h
+++ b/include/time.h
@@ -209,6 +209,14 @@ libc_hidden_proto (__difftime64)
 
 extern double __difftime (time_t time1, time_t time0);
 
+#if __TIMESIZE == 64
+# define __clock_nanosleep_time64 __clock_nanosleep
+#else
+extern int __clock_nanosleep_time64 (clockid_t clock_id,
+                                     int flags, const struct __timespec64 *req,
+                                     struct __timespec64 *rem);
+libc_hidden_proto (__clock_nanosleep_time64)
+#endif
 
 /* Use in the clock_* functions.  Size of the field representing the
    actual clock ID.  */
diff --git a/sysdeps/unix/sysv/linux/clock_nanosleep.c b/sysdeps/unix/sysv/linux/clock_nanosleep.c
index f3c6fd2d5f7..903ed58e218 100644
--- a/sysdeps/unix/sysv/linux/clock_nanosleep.c
+++ b/sysdeps/unix/sysv/linux/clock_nanosleep.c
@@ -16,6 +16,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <time.h>
+#include <kernel-features.h>
 #include <errno.h>
 
 #include <sysdep-cancel.h>
@@ -26,9 +27,11 @@
 /* We can simply use the syscall.  The CPU clocks are not supported
    with this function.  */
 int
-__clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
-		   struct timespec *rem)
+__clock_nanosleep_time64 (clockid_t clock_id, int flags, const struct __timespec64 *req,
+                          struct __timespec64 *rem)
 {
+  int r;
+
   if (clock_id == CLOCK_THREAD_CPUTIME_ID)
     return EINVAL;
   if (clock_id == CLOCK_PROCESS_CPUTIME_ID)
@@ -37,11 +40,61 @@ __clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
   /* If the call is interrupted by a signal handler or encounters an error,
      it returns a positive value similar to errno.  */
   INTERNAL_SYSCALL_DECL (err);
-  int r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep, err, clock_id, flags,
-				   req, rem);
+
+#ifdef __ASSUME_TIME64_SYSCALLS
+# ifndef __NR_clock_nanosleep_time64
+#  define __NR_clock_nanosleep_time64 __NR_clock_nanosleep
+# endif
+  r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, clock_id,
+                               flags, req, rem);
+#else
+# ifdef __NR_clock_nanosleep_time64
+  r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, clock_id,
+                               flags, req, rem);
+
+  if (r == 0 || errno != ENOSYS)
+    {
+      return (INTERNAL_SYSCALL_ERROR_P (r, err)
+              ? INTERNAL_SYSCALL_ERRNO (r, err) : 0);
+    }
+# endif /* __NR_clock_nanosleep_time64 */
+  struct timespec ts32, tr32;
+
+  if (! in_time_t_range (req->tv_sec))
+    {
+      __set_errno (EOVERFLOW);
+      return -1;
+    }
+
+  ts32 = valid_timespec64_to_timespec (*req);
+  r =  INTERNAL_SYSCALL_CANCEL (clock_nanosleep, err, clock_id, flags,
+                                &ts32, &tr32);
+
+  if (r == 0 && rem)
+    *rem = valid_timespec_to_timespec64 (tr32);
+#endif /* __ASSUME_TIME64_SYSCALLS */
+
   return (INTERNAL_SYSCALL_ERROR_P (r, err)
 	  ? INTERNAL_SYSCALL_ERRNO (r, err) : 0);
 }
+
+#if __TIMESIZE != 64
+int
+__clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
+                   struct timespec *rem)
+{
+  int r;
+  struct __timespec64 treq64, trem64;
+
+  treq64 = valid_timespec_to_timespec64 (*req);
+  r = __clock_nanosleep_time64 (clock_id, flags, &treq64, &trem64);
+
+  if (r == 0 && rem)
+    *rem = valid_timespec64_to_timespec (trem64);
+
+  return r;
+}
+#endif
 libc_hidden_def (__clock_nanosleep)
 versioned_symbol (libc, __clock_nanosleep, clock_nanosleep, GLIBC_2_17);
 /* clock_nanosleep moved to libc in version 2.17;
-- 
2.23.0