Finish move of clock_* functions to libc. [BZ #24959]

In glibc 2.17, the functions clock_getcpuclockid, clock_getres,
clock_gettime, clock_nanosleep, and clock_settime were moved from
librt.so to libc.so, leaving compatibility stubs behind.  Now that the
dynamic linker no longer insists on finding versioned symbols in the
same library that originally defined them, we do not need the stubs
anymore, and this means we don't need GLIBC_PRIVATE __-prefix aliases
for most of the functions anymore either.  (clock_gettime still needs
one.)  For ports added before 2.17, libc.so needs to provide two
symbol versions for each, the default at GLIBC_2.17 plus a compat
version matching what librt had.

While I'm at it, move the clock_*.c files and their tests from rt/ to
time/.

1 files changed, 47 insertions, 0 deletions

diff --git a/time/clock_getcpuclockid.c b/time/clock_getcpuclockid.c
new file mode 100644
index 0000000000..8d205abfa9
--- /dev/null
+++ b/time/clock_getcpuclockid.c
@@ -0,0 +1,47 @@
+/* Get a clockid_t for the process CPU clock of a given process.  Generic.
+   Copyright (C) 2000-2019 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <time.h>
+#include <unistd.h>
+#include <shlib-compat.h>
+
+int
+__clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
+{
+  /* We don't allow any process ID but our own.  */
+  if (pid != 0 && pid != getpid ())
+    return EPERM;
+
+#ifdef CLOCK_PROCESS_CPUTIME_ID
+  /* Store the number.  */
+  *clock_id = CLOCK_PROCESS_CPUTIME_ID;
+
+  return 0;
+#else
+  /* We don't have a timer for that.  */
+  return ENOENT;
+#endif
+}
+versioned_symbol (libc, __clock_getcpuclockid, clock_getcpuclockid, GLIBC_2_17);
+/* clock_getcpuclockid 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_getcpuclockid, __clock_getcpuclockid_2);
+compat_symbol (libc, __clock_getcpuclockid_2, clock_getcpuclockid, GLIBC_2_2);
+#endif