[RFC v3 01/23] 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()"

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 ChangeLog                                    |  6 +++
 nptl/thrd_sleep.c                            | 41 +++++++++++++++-
 sysdeps/unix/sysv/linux/clock_nanosleep.c    | 42 +++++++++++++++-
 sysdeps/unix/sysv/linux/nanosleep.c          | 50 ++++++++++++++++++++
 sysdeps/unix/sysv/linux/nanosleep_nocancel.c | 11 +++++
 5 files changed, 147 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index bd57a815b0..477b9b49b3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1023,6 +1023,12 @@
 
 	* support/xtime.h: Add xclock_now() helper function.
 
+2019-06-21  Alistair Francis  <alistair.francis@wdc.com>
+
+	* nptl/thrd_sleep.c: Use clock_nanosleep_time64 instead of nanosleep.
+	* sysdeps/unix/sysv/linux/nanosleep.c: Likewise.
+	* sysdeps/unix/sysv/linux/nanosleep_nocancel.c: Likewise.
+
 2019-06-20  Dmitry V. Levin  <ldv@altlinux.org>
 	    Florian Weimer  <fweimer@redhat.com>
 
diff --git a/nptl/thrd_sleep.c b/nptl/thrd_sleep.c
index 07a51808df..e7873a7170 100644
--- a/nptl/thrd_sleep.c
+++ b/nptl/thrd_sleep.c
@@ -21,11 +21,50 @@
 
 #include "thrd_priv.h"
 
+#if __TIMESIZE == 32
+struct timespec64
+{
+  long int tv_sec;   /* Seconds.  */
+  long int tv_nsec;  /* Nanoseconds.  */
+};
+#endif
+
 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);
+  int ret;
+
+#ifdef __ASSUME_TIME64_SYSCALLS
+  ret = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, CLOCK_REALTIME,
+                                 0, time_point, remaining);
+#else
+# ifdef __NR_clock_nanosleep_time64
+#  if __TIMESIZE == 64
+  long int ret_64;
+
+  ret_64 = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, CLOCK_REALTIME,
+                                    0, time_point, remaining);
+
+  if (ret_64 == 0 || errno != ENOSYS)
+    ret = ret_64;
+#  else
+  timespec64 ts;
+
+  ret = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err,
+                                 CLOCK_REALTIME, 0, time_point,
+                                 ts);
+
+  if (ret == 0 || errno != ENOSYS) {
+    remaining->tv_sec = ts.tv_sec;
+    remaining->tv_nsec = ts.tv_nsec;
+    return ret;
+  }
+#  endif
+# endif
+  ret =  INTERNAL_SYSCALL_CANCEL (nanosleep, err, time_point, remaining);
+#endif
+
   if (INTERNAL_SYSCALL_ERROR_P (ret, err))
     {
       /* C11 states thrd_sleep function returns -1 if it has been interrupted
diff --git a/sysdeps/unix/sysv/linux/clock_nanosleep.c b/sysdeps/unix/sysv/linux/clock_nanosleep.c
index 0cb6614dc9..84bd5f8afc 100644
--- a/sysdeps/unix/sysv/linux/clock_nanosleep.c
+++ b/sysdeps/unix/sysv/linux/clock_nanosleep.c
@@ -21,6 +21,13 @@
 #include <sysdep-cancel.h>
 #include "kernel-posix-cpu-timers.h"
 
+#if __TIMESIZE == 32
+struct timespec64
+{
+  long int tv_sec;   /* Seconds.  */
+  long int tv_nsec;  /* Nanoseconds.  */
+};
+#endif
 
 /* We can simply use the syscall.  The CPU clocks are not supported
    with this function.  */
@@ -28,6 +35,8 @@ int
 __clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
 		   struct timespec *rem)
 {
+  int r;
+
   if (clock_id == CLOCK_THREAD_CPUTIME_ID)
     return EINVAL;
   if (clock_id == CLOCK_PROCESS_CPUTIME_ID)
@@ -36,8 +45,37 @@ __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
+  r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, clock_id,
+                               flags, req, rem);
+#else
+# ifdef __NR_clock_nanosleep_time64
+#  if __TIMESIZE == 64
+  long int ret_64;
+
+  ret_64 = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, clock_id,
+                                    flags, req, rem);
+
+  if (ret_64 == 0 || errno != ENOSYS)
+    r = ret_64;
+#  else
+  timespec64 ts;
+
+  r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err,
+                               clock_id, flags, req,
+                               ts);
+
+  if (r == 0 || errno != ENOSYS) {
+    rem->tv_sec = ts.tv_sec;
+    rem->tv_nsec = ts.tv_nsec;
+    return r;
+  }
+#  endif
+# endif
+  r =  INTERNAL_SYSCALL_CANCEL (clock_nanosleep, err, req, rem);
+#endif
+
   return (INTERNAL_SYSCALL_ERROR_P (r, err)
 	  ? INTERNAL_SYSCALL_ERRNO (r, err) : 0);
 }
diff --git a/sysdeps/unix/sysv/linux/nanosleep.c b/sysdeps/unix/sysv/linux/nanosleep.c
index f14ae565af..0c54f21e07 100644
--- a/sysdeps/unix/sysv/linux/nanosleep.c
+++ b/sysdeps/unix/sysv/linux/nanosleep.c
@@ -20,12 +20,62 @@
 #include <sysdep-cancel.h>
 #include <not-cancel.h>
 
+#if defined(__ASSUME_TIME64_SYSCALLS) || defined(__NR_clock_nanosleep_time64)
+static int
+__nanosleep_time64_64 (const struct timespec *requested_time,
+                       struct timespec *remaining)
+{
+  return SYSCALL_CANCEL (clock_nanosleep_time64, CLOCK_REALTIME, 0,
+                         requested_time, remaining);
+}
+
+#if __TIMESIZE == 32
+struct timespec64
+{
+  long int tv_sec;   /* Seconds.  */
+  long int tv_nsec;  /* Nanoseconds.  */
+};
+
+static int
+__nanosleep_time64_32 (const struct timespec *requested_time,
+                       struct timespec *remaining)
+{
+  timespec64 ts;
+
+  long int ret = SYSCALL_CANCEL (clock_nanosleep_time64, CLOCK_REALTIME, 0,
+                                 requested_time, &ts);
+
+  remaining->tv_sec = ts.tv_sec;
+  remaining->tv_nsec = ts.tv_nsec;
+
+  return ret;
+}
+#endif
+#endif
+
 /* Pause execution for a number of nanoseconds.  */
 int
 __nanosleep (const struct timespec *requested_time,
 	     struct timespec *remaining)
 {
+#ifdef __ASSUME_TIME64_SYSCALLS
+  return __nanosleep_time64_64 (requested_time, remaining);
+#else
+# ifdef __NR_clock_nanosleep_time64
+#  if __TIMESIZE == 64
+  long int ret = __nanosleep_time64_64 (requested_time, remaining);
+
+  if (ret == 0 || errno != ENOSYS)
+    return ret;
+#  else
+  long int ret = __nanosleep_time64_32 (requested_time, remaining);
+
+  if (ret == 0 || errno != ENOSYS)
+    return ret;
+#  endif
+# endif
   return SYSCALL_CANCEL (nanosleep, requested_time, remaining);
+#endif
 }
 hidden_def (__nanosleep)
 weak_alias (__nanosleep, nanosleep)
diff --git a/sysdeps/unix/sysv/linux/nanosleep_nocancel.c b/sysdeps/unix/sysv/linux/nanosleep_nocancel.c
index 122ba627ff..f411a1c6c2 100644
--- a/sysdeps/unix/sysv/linux/nanosleep_nocancel.c
+++ b/sysdeps/unix/sysv/linux/nanosleep_nocancel.c
@@ -24,6 +24,17 @@ int
 __nanosleep_nocancel (const struct timespec *requested_time,
 		      struct timespec *remaining)
 {
+#ifdef __ASSUME_TIME64_SYSCALLS
+  return INLINE_SYSCALL_CALL (clock_nanosleep_time64, CLOCK_REALTIME, 0,
+                         requested_time, remaining);
+#else
+# ifdef __NR_clock_nanosleep_time64
+  long int ret = INLINE_SYSCALL_CALL (clock_nanosleep_time64, CLOCK_REALTIME, 0,
+                                 requested_time, remaining);
+  if (ret == 0 || errno != ENOSYS)
+    return ret;
+# endif
   return INLINE_SYSCALL_CALL (nanosleep, requested_time, remaining);
+#endif
 }
 hidden_def (__nanosleep_nocancel)
-- 
2.22.0