[glibc/zack/y2038-preliminaries] Use clock_gettime to implement time.

[Zack Weinberg <zack@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f4e5cd6bbe38b3454bf683453d080b073ecec3ca

commit f4e5cd6bbe38b3454bf683453d080b073ecec3ca
Author: Zack Weinberg <zackw@panix.com>
Date:   Fri Aug 16 14:22:42 2019 -0400

    Use clock_gettime to implement time.
    
    Most ports were using gettimeofday to implement time, or they were
    making a direct (v)syscall.  Unconditionally switch to using
    clock_gettime instead.  All sysdeps implementations of time are
    removed.
    
    	* time/time.c (time): No longer a stub implementation.
    	Call __clock_gettime.
    
    	* sysdeps/unix/sysv/linux/powerpc/Versions (GLIBC_PRIVATE):
    	Remove __vdso_time.
    	* sysdeps/unix/sysv/linux/powerpc/init-first.c (__vdso_time): Delete.
    	(_libc_vdso_platform_setup): Don't initialize __vdso_time.
    	* sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list: Remove entry
    	for time.
    
    	* sysdeps/posix/time.c
    	* sysdeps/unix/sysv/linux/time.c
    	* sysdeps/unix/sysv/linux/i386/time.c
    	* sysdeps/unix/sysv/linux/powerpc/time.c
    	* sysdeps/unix/sysv/linux/sparc/sparc64/time.c
    	* sysdeps/unix/sysv/linux/x86/time.c:
    	Delete file.

Diff:
---
 sysdeps/posix/time.c                             | 40 -----------
 sysdeps/unix/sysv/linux/i386/time.c              | 34 ----------
 sysdeps/unix/sysv/linux/powerpc/Versions         |  1 -
 sysdeps/unix/sysv/linux/powerpc/init-first.c     |  5 --
 sysdeps/unix/sysv/linux/powerpc/time.c           | 84 ------------------------
 sysdeps/unix/sysv/linux/sparc/sparc64/time.c     |  1 -
 sysdeps/unix/sysv/linux/time.c                   | 41 ------------
 sysdeps/unix/sysv/linux/x86/time.c               | 59 -----------------
 sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list |  1 -
 time/time.c                                      | 12 ++--
 10 files changed, 5 insertions(+), 273 deletions(-)

diff --git a/sysdeps/posix/time.c b/sysdeps/posix/time.c
deleted file mode 100644
index e1b3bc8..0000000
--- a/sysdeps/posix/time.c
+++ /dev/null
@@ -1,40 +0,0 @@
-/* Copyright (C) 1991-2019 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 <stddef.h>		/* For NULL.  */
-#include <time.h>
-#include <sys/time.h>
-
-
-/* Return the current time as a `time_t' and also put it in *T if T is
-   not NULL.  Time is represented as seconds from Jan 1 00:00:00 1970.  */
-time_t
-time (time_t *t)
-{
-  struct timeval tv;
-  time_t result;
-
-  if (__gettimeofday (&tv, (struct timezone *) NULL))
-    result = (time_t) -1;
-  else
-    result = (time_t) tv.tv_sec;
-
-  if (t != NULL)
-    *t = result;
-  return result;
-}
-libc_hidden_def (time)
diff --git a/sysdeps/unix/sysv/linux/i386/time.c b/sysdeps/unix/sysv/linux/i386/time.c
deleted file mode 100644
index 440e3e6..0000000
--- a/sysdeps/unix/sysv/linux/i386/time.c
+++ /dev/null
@@ -1,34 +0,0 @@
-/* time -- Get number of seconds since Epoch.  Linux/i386 version.
-   Copyright (C) 2015-2019 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/>.  */
-
-#ifdef SHARED
-# define time __redirect_time
-#endif
-
-#include <time.h>
-
-#ifdef SHARED
-# undef time
-# define time_type __redirect_time
-
-# undef libc_hidden_def
-# define libc_hidden_def(name)  \
-  __hidden_ver1 (__time_syscall, __GI_time, __time_syscall);
-#endif
-
-#include <sysdeps/unix/sysv/linux/x86/time.c>
diff --git a/sysdeps/unix/sysv/linux/powerpc/Versions b/sysdeps/unix/sysv/linux/powerpc/Versions
index 8ebeea1..859e0d7 100644
--- a/sysdeps/unix/sysv/linux/powerpc/Versions
+++ b/sysdeps/unix/sysv/linux/powerpc/Versions
@@ -10,7 +10,6 @@ libc {
     __vdso_clock_gettime;
     __vdso_clock_getres;
     __vdso_getcpu;
-    __vdso_time;
   }
 }
 libm {
diff --git a/sysdeps/unix/sysv/linux/powerpc/init-first.c b/sysdeps/unix/sysv/linux/powerpc/init-first.c
index 831f910..4f12b59 100644
--- a/sysdeps/unix/sysv/linux/powerpc/init-first.c
+++ b/sysdeps/unix/sysv/linux/powerpc/init-first.c
@@ -25,7 +25,6 @@ int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *);
 int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *);
 unsigned long long (*VDSO_SYMBOL(get_tbfreq)) (void);
 int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *);
-time_t (*VDSO_SYMBOL(time)) (time_t *);
 
 #if defined(__PPC64__) || defined(__powerpc64__)
 void *VDSO_SYMBOL(sigtramp_rt64);
@@ -59,10 +58,6 @@ _libc_vdso_platform_setup (void)
   PTR_MANGLE (p);
   VDSO_SYMBOL (getcpu) = p;
 
-  p = _dl_vdso_vsym ("__kernel_time", &linux2615);
-  PTR_MANGLE (p);
-  VDSO_SYMBOL (time) = p;
-
   /* PPC64 uses only one signal trampoline symbol, while PPC32 will use
      two depending if SA_SIGINFO is used (__kernel_sigtramp_rt32) or not
      (__kernel_sigtramp32).
diff --git a/sysdeps/unix/sysv/linux/powerpc/time.c b/sysdeps/unix/sysv/linux/powerpc/time.c
deleted file mode 100644
index cb3e8b9..0000000
--- a/sysdeps/unix/sysv/linux/powerpc/time.c
+++ /dev/null
@@ -1,84 +0,0 @@
-/* time system call for Linux/PowerPC.
-   Copyright (C) 2013-2019 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/>.  */
-
-#ifdef SHARED
-# ifndef __powerpc64__
-#  define time __redirect_time
-# else
-#  define __redirect_time time
-# endif
-
-# include <time.h>
-# include <sysdep.h>
-# include <dl-vdso.h>
-# include <libc-vdso.h>
-# include <dl-machine.h>
-
-# ifndef __powerpc64__
-#  undef time
-
-time_t
-__time_vsyscall (time_t *t)
-{
-  return INLINE_VSYSCALL (time, 1, t);
-}
-
-/* __GI_time is defined as hidden and for ppc32 it enables the
-   compiler make a local call (symbol@local) for internal GLIBC usage. It
-   means the PLT won't be used and the ifunc resolver will be called directly.
-   For ppc64 a call to a function in another translation unit might use a
-   different toc pointer thus disallowing direct branchess and making internal
-   ifuncs calls safe.  */
-#  undef libc_hidden_def
-#  define libc_hidden_def(name)					\
-  __hidden_ver1 (__time_vsyscall, __GI_time, __time_vsyscall);
-
-# endif /* !__powerpc64__  */
-
-static time_t
-time_syscall (time_t *t)
-{
-  struct timeval tv;
-  time_t result;
-
-  if (INLINE_VSYSCALL (gettimeofday, 2, &tv, NULL) < 0)
-    result = (time_t) -1;
-  else
-    result = (time_t) tv.tv_sec;
-
-  if (t != NULL)
-    *t = result;
-  return result;
-}
-
-# define INIT_ARCH()						\
-  PREPARE_VERSION_KNOWN (linux2615, LINUX_2_6_15);		\
-  void *vdso_time = _dl_vdso_vsym ("__kernel_time", &linux2615);
-
-/* If the vDSO is not available we fall back to the syscall.  */
-libc_ifunc_hidden (__redirect_time, time,
-		   vdso_time
-		   ? VDSO_IFUNC_RET (vdso_time)
-		   : (void *) time_syscall);
-libc_hidden_def (time)
-
-#else
-
-#include <sysdeps/posix/time.c>
-
-#endif /* !SHARED */
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/time.c b/sysdeps/unix/sysv/linux/sparc/sparc64/time.c
deleted file mode 100644
index 509b580..0000000
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/time.c
+++ /dev/null
@@ -1 +0,0 @@
-#include <sysdeps/posix/time.c>
diff --git a/sysdeps/unix/sysv/linux/time.c b/sysdeps/unix/sysv/linux/time.c
deleted file mode 100644
index 1978f6d..0000000
--- a/sysdeps/unix/sysv/linux/time.c
+++ /dev/null
@@ -1,41 +0,0 @@
-/* Copyright (C) 2005-2019 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 <stddef.h>
-#include <time.h>
-
-#include <sysdep.h>
-
-#ifdef __NR_time
-
-time_t
-time (time_t *t)
-{
-  INTERNAL_SYSCALL_DECL (err);
-  time_t res = INTERNAL_SYSCALL (time, err, 1, NULL);
-  /* There cannot be any error.  */
-  if (t != NULL)
-    *t = res;
-  return res;
-}
-libc_hidden_def (time)
-
-#else
-
-# include <sysdeps/posix/time.c>
-
-#endif
diff --git a/sysdeps/unix/sysv/linux/x86/time.c b/sysdeps/unix/sysv/linux/x86/time.c
deleted file mode 100644
index 3d72488..0000000
--- a/sysdeps/unix/sysv/linux/x86/time.c
+++ /dev/null
@@ -1,59 +0,0 @@
-/* time -- Get number of seconds since Epoch.  Linux/x86 version.
-   Copyright (C) 2015-2019 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 <time.h>
-
-#ifdef SHARED
-
-#include <dl-vdso.h>
-#include <errno.h>
-
-static time_t
-__time_syscall (time_t *t)
-{
-  INTERNAL_SYSCALL_DECL (err);
-  return INTERNAL_SYSCALL (time, err, 1, t);
-}
-
-# ifndef time_type
-/* The i386 time.c includes this file with a defined time_type macro.
-   For x86_64 we have to define it to time as the internal symbol is the
-   ifunc'ed one.  */
-#  define time_type time
-# endif
-
-#undef INIT_ARCH
-#define INIT_ARCH() PREPARE_VERSION_KNOWN (linux26, LINUX_2_6);
-/* If the vDSO is not available we fall back on the syscall.  */
-libc_ifunc_hidden (time_type, time,
-		   (_dl_vdso_vsym ("__vdso_time", &linux26)
-		    ?:  &__time_syscall))
-libc_hidden_def (time)
-
-#else
-
-# include <sysdep.h>
-
-time_t
-time (time_t *t)
-{
-  INTERNAL_SYSCALL_DECL (err);
-  return INTERNAL_SYSCALL (time, err, 1, t);
-}
-
-#endif
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list b/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
index b44f6f9..c0cfa7b 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
@@ -3,4 +3,3 @@
 gettimeofday	-	gettimeofday:__vdso_gettimeofday@LINUX_2.6	i:pP	__gettimeofday	gettimeofday
 personality	EXTRA	personality	Ei:i	__personality	personality
 posix_fadvise64	-	fadvise64	Vi:iiii	posix_fadvise	posix_fadvise64
-time		-	time:__vdso_time@LINUX_2.6			Ei:P	time
diff --git a/time/time.c b/time/time.c
index 88612d6..bae0fd1 100644
--- a/time/time.c
+++ b/time/time.c
@@ -15,19 +15,17 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
 #include <time.h>
 
 /* Return the time now, and store it in *TIMER if not NULL.  */
 time_t
 time (time_t *timer)
 {
-  __set_errno (ENOSYS);
+  struct timespec ts;
+  __clock_gettime (CLOCK_REALTIME, &ts);
 
-  if (timer != NULL)
-    *timer = (time_t) -1;
-  return (time_t) -1;
+  if (timer)
+    *timer = ts.tv_sec;
+  return ts.tv_sec;
 }
 libc_hidden_def (time)
-
-stub_warning (time)