Refactor nanosleep in terms of clock_nanosleep

The generic version is straightforward.  For Hurd, its nanosleep
implementation is moved to clock_nanosleep with adjustments from
generic unix implementation.

The generic clock_nanosleep unix version is also removed since
it calls nanosleep.

Checked on x86_64-linux-gnu and powerpc64le-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

2 files changed, 111 insertions, 79 deletions

diff --git a/sysdeps/mach/clock_nanosleep.c b/sysdeps/mach/clock_nanosleep.c
new file mode 100644
index 0000000000..6dc67d649f
--- /dev/null
+++ b/sysdeps/mach/clock_nanosleep.c
@@ -0,0 +1,111 @@
+/* clock_nanosleep - high-resolution sleep with specifiable clock.
+   Copyright (C) 2002-2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <mach.h>
+#include <time.h>
+#include <unistd.h>
+#include <posix-timer.h>
+#include <shlib-compat.h>
+
+static int
+nanosleep_call (const struct timespec *req, struct timespec *rem)
+{
+  mach_port_t recv;
+  struct timespec before;
+  error_t err;
+
+  const mach_msg_timeout_t ms
+    = req->tv_sec * 1000
+    + (req->tv_nsec + 999999) / 1000000;
+
+  recv = __mach_reply_port ();
+
+  if (rem != NULL)
+    __clock_gettime (CLOCK_REALTIME, &before);
+
+  err = __mach_msg (NULL, MACH_RCV_MSG|MACH_RCV_TIMEOUT|MACH_RCV_INTERRUPT,
+                    0, 0, recv, ms, MACH_PORT_NULL);
+  __mach_port_destroy (mach_task_self (), recv);
+  if (err == EMACH_RCV_INTERRUPTED)
+    {
+      if (rem != NULL)
+	{
+	  struct timespec after, elapsed;
+	  __clock_gettime (CLOCK_REALTIME, &after);
+	  timespec_sub (&elapsed, &after, &before);
+	  timespec_sub (rem, req, &elapsed);
+	}
+
+      return EINTR;
+    }
+
+  return 0;
+}
+
+int
+__clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
+		   struct timespec *rem)
+{
+  if (clock_id != CLOCK_REALTIME
+      || !valid_nanoseconds (req->tv_nsec)
+      || (flags != 0 && flags != TIMER_ABSTIME))
+    return EINVAL;
+
+  struct timespec now;
+
+  /* If we got an absolute time, remap it.  */
+  if (flags == TIMER_ABSTIME)
+    {
+      long int nsec;
+      long int sec;
+
+      /* Make sure we use safe data types.  */
+      assert (sizeof (sec) >= sizeof (now.tv_sec));
+
+      /* Get the current time for this clock.  */
+      if (__clock_gettime (clock_id, &now) != 0)
+	return errno;
+
+      /* Compute the difference.  */
+      nsec = req->tv_nsec - now.tv_nsec;
+      sec = req->tv_sec - now.tv_sec - (nsec < 0);
+      if (sec < 0)
+	/* The time has already elapsed.  */
+	return 0;
+
+      now.tv_sec = sec;
+      now.tv_nsec = nsec + (nsec < 0 ? 1000000000 : 0);
+
+      /* From now on this is our time.  */
+      req = &now;
+
+      /* Make sure we are not modifying the struct pointed to by REM.  */
+      rem = NULL;
+    }
+
+  return nanosleep_call (req, rem);
+}
+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.  */
+#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
+strong_alias (__clock_nanosleep, __clock_nanosleep_2);
+compat_symbol (libc, __clock_nanosleep_2, clock_nanosleep, GLIBC_2_2);
+#endif
diff --git a/sysdeps/mach/nanosleep.c b/sysdeps/mach/nanosleep.c
deleted file mode 100644
index b60a2179f6..0000000000
--- a/sysdeps/mach/nanosleep.c
+++ /dev/null
@@ -1,79 +0,0 @@
-/* nanosleep -- sleep for a period specified with a struct timespec
-   Copyright (C) 2002-2019 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <errno.h>
-#include <mach.h>
-#include <time.h>
-#include <unistd.h>
-
-# define timespec_sub(a, b, result)					      \
-  do {									      \
-    (result)->tv_sec = (a)->tv_sec - (b)->tv_sec;			      \
-    (result)->tv_nsec = (a)->tv_nsec - (b)->tv_nsec;			      \
-    if ((result)->tv_nsec < 0) {					      \
-      --(result)->tv_sec;						      \
-      (result)->tv_nsec += 1000000000;					      \
-    }									      \
-  } while (0)
-
-int
-__libc_nanosleep (const struct timespec *requested_time,
-                  struct timespec *remaining)
-{
-  mach_port_t recv;
-  struct timespec before;
-  error_t err;
-
-  if (requested_time->tv_sec < 0
-      || ! valid_nanoseconds (requested_time->tv_nsec))
-    {
-      errno = EINVAL;
-      return -1;
-    }
-
-  const mach_msg_timeout_t ms
-    = requested_time->tv_sec * 1000
-    + (requested_time->tv_nsec + 999999) / 1000000;
-
-  recv = __mach_reply_port ();
-
-  if (remaining != 0)
-    __clock_gettime (CLOCK_REALTIME, &before);
-
-  err = __mach_msg (NULL, MACH_RCV_MSG|MACH_RCV_TIMEOUT|MACH_RCV_INTERRUPT,
-                    0, 0, recv, ms, MACH_PORT_NULL);
-  __mach_port_destroy (mach_task_self (), recv);
-  if (err == EMACH_RCV_INTERRUPTED)
-    {
-      if (remaining != 0)
-	{
-	  struct timespec after, elapsed;
-	  __clock_gettime (CLOCK_REALTIME, &after);
-	  timespec_sub (&after, &before, &elapsed);
-	  timespec_sub (requested_time, &elapsed, remaining);
-	}
-
-      errno = EINTR;
-      return -1;
-    }
-
-  return 0;
-}
-weak_alias(__libc_nanosleep, __nanosleep)
-libc_hidden_def (__nanosleep)
-weak_alias (__libc_nanosleep, nanosleep)