[PATCH v4] sysdeps/nanosleep: Use clock_nanosleep_time64 if avaliable

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

The 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.

Let's use CLOCK_REALTIME when calling clock_nanosleep_time64 as the
Linux specification says:
  "POSIX.1 specifies that nanosleep() should measure time against the
   CLOCK_REALTIME clock. However, Linux measures the time using the
   CLOCK_MONOTONIC clock. This probably does not matter, since the POSIX.1
   specification for clock_settime(2) says that discontinuous changes in
   CLOCK_REALTIME should not affect nanosleep()"

Let's also expose __clock_nanosleep internally to avoid code
duplication.
---
This was patch was runtime tested with RV32 and RV64
It was build tested using the ./scripts/build-many-glibcs.py script.

I am currently running:
$ 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
I should have the results tomorrow.

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                            | 23 ++++++++
 nptl/thrd_sleep.c                         | 25 ++++-----
 sysdeps/unix/sysv/linux/Versions          |  1 +
 sysdeps/unix/sysv/linux/clock_nanosleep.c | 68 +++++++++++++++++++++--
 sysdeps/unix/sysv/linux/nanosleep.c       | 13 +++--
 5 files changed, 106 insertions(+), 24 deletions(-)

diff --git a/include/time.h b/include/time.h
index 8ac58e891b5..e0974309726 100644
--- a/include/time.h
+++ b/include/time.h
@@ -184,6 +184,9 @@ extern struct tm *__tz_convert (__time64_t timer, int use_localtime,
 extern int __nanosleep (const struct timespec *__requested_time,
 			struct timespec *__remaining);
 hidden_proto (__nanosleep)
+extern int __clock_nanosleep (clockid_t clock_id, int flags,
+                              const struct timespec *req, struct timespec *rem);
+libc_hidden_proto (__clock_nanosleep)
 extern int __getdate_r (const char *__string, struct tm *__resbufp)
   attribute_hidden;
 
@@ -206,6 +209,26 @@ libc_hidden_proto (__difftime64)
 
 extern double __difftime (time_t time1, time_t time0);
 
+#if __TIMESIZE == 64
+# define __thrd_sleep_time64 thrd_sleep
+# define __clock_nanosleep_time64 __clock_nanosleep
+# define __nanosleep_time64 __nanosleep
+# define __nanosleep_nocancel_time64 __nanosleep_nocancel
+#else
+extern int __thrd_sleep_time64 (const struct __timespec64* time_point,
+                                struct __timespec64* remaining);
+libc_hidden_proto (__thrd_sleep_time64)
+extern int __clock_nanosleep_time64 (clockid_t clock_id,
+                                     int flags, const struct __timespec64 *req,
+                                     struct __timespec64 *rem);
+libc_hidden_proto (__clock_nanosleep_time64)
+extern int __nanosleep_time64 (const struct __timespec64 *requested_time,
+                                struct __timespec64 *remaining);
+libc_hidden_proto (__nanosleep_time64)
+extern int __nanosleep_nocancel_time64 (const struct __timespec64 *requested_time,
+                                        struct __timespec64 *remaining);
+libc_hidden_proto (__nanosleep_nocancel_time64)
+#endif
 
 /* Use in the clock_* functions.  Size of the field representing the
    actual clock ID.  */
diff --git a/nptl/thrd_sleep.c b/nptl/thrd_sleep.c
index 2e185dd748e..c865f815eea 100644
--- a/nptl/thrd_sleep.c
+++ b/nptl/thrd_sleep.c
@@ -17,23 +17,18 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <time.h>
-#include <sysdep-cancel.h>
-
-#include "thrd_priv.h"
+#include <errno.h>
 
 int
 thrd_sleep (const struct timespec* time_point, struct timespec* remaining)
 {
-  INTERNAL_SYSCALL_DECL (err);
-  int ret = INTERNAL_SYSCALL_CANCEL (nanosleep, err, time_point, remaining);
-  if (INTERNAL_SYSCALL_ERROR_P (ret, err))
-    {
-      /* C11 states thrd_sleep function returns -1 if it has been interrupted
-	 by a signal, or a negative value if it fails.  */
-      ret = INTERNAL_SYSCALL_ERRNO (ret, err);
-      if (ret == EINTR)
-	return -1;
-      return -2;
-    }
-  return 0;
+  int ret = __clock_nanosleep (CLOCK_REALTIME, 0, time_point, remaining);
+  /* C11 states thrd_sleep function returns -1 if it has been interrupted
+     by a signal, or a negative value if it fails.  */
+  switch (ret)
+  {
+     case 0:      return 0;
+     case EINTR:  return -1;
+     default:     return -2;
+  }
 }
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index d385085c611..475abb50040 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -187,5 +187,6 @@ libc {
     __sigtimedwait;
     # functions used by nscd
     __netlink_assert_response;
+    __clock_nanosleep;
   }
 }
diff --git a/sysdeps/unix/sysv/linux/clock_nanosleep.c b/sysdeps/unix/sysv/linux/clock_nanosleep.c
index 1f240b8720a..13ea9c6f802 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 = -1;
+
   if (clock_id == CLOCK_THREAD_CPUTIME_ID)
     return EINVAL;
   if (clock_id == CLOCK_PROCESS_CPUTIME_ID)
@@ -37,12 +40,67 @@ __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
+  long int ret_64;
+
+  ret_64 = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, clock_id,
+                                    flags, req, rem);
+
+  if (ret_64 == 0 || errno != ENOSYS)
+    {
+      return (INTERNAL_SYSCALL_ERROR_P (ret_64, err)
+              ? INTERNAL_SYSCALL_ERRNO (ret_64, 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, &ts32, &tr32);
+
+  if ((r == 0 || errno != ENOSYS) && rem)
+    *rem = valid_timespec_to_timespec64 (tr32);
+#endif /* __ASSUME_TIME64_SYSCALLS */
+
   return (INTERNAL_SYSCALL_ERROR_P (r, err)
-	  ? INTERNAL_SYSCALL_ERRNO (r, err) : 0);
+          ? 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 || errno != ENOSYS)
+    {
+      if (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;
    old binaries may expect the symbol version it had in librt.  */
diff --git a/sysdeps/unix/sysv/linux/nanosleep.c b/sysdeps/unix/sysv/linux/nanosleep.c
index 6787909248f..30cc26909a7 100644
--- a/sysdeps/unix/sysv/linux/nanosleep.c
+++ b/sysdeps/unix/sysv/linux/nanosleep.c
@@ -17,15 +17,20 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <time.h>
-#include <sysdep-cancel.h>
-#include <not-cancel.h>
+#include <errno.h>
 
 /* Pause execution for a number of nanoseconds.  */
 int
 __nanosleep (const struct timespec *requested_time,
-	     struct timespec *remaining)
+             struct timespec *remaining)
 {
-  return SYSCALL_CANCEL (nanosleep, requested_time, remaining);
+  int ret = __clock_nanosleep (CLOCK_REALTIME, 0, requested_time, remaining);
+  if (ret != 0)
+    {
+      __set_errno (ret);
+      return -1;
+    }
+  return ret;
 }
 hidden_def (__nanosleep)
 weak_alias (__nanosleep, nanosleep)
-- 
2.23.0