[glibc/azanella/y2038-preliminaries] Consolidate and deprecate ftime

[Adhemerval Zanella <azanella at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=bf49c54dab20abe5f0a5efc73f934e475af10233

commit bf49c54dab20abe5f0a5efc73f934e475af10233
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Wed Sep 4 16:51:23 2019 +0000

    Consolidate and deprecate ftime
    
    ftime is an obsolete variation on gettimeofday, offering only
    millisecond time resolution; it was probably a system call in ooold
    versions of BSD Unix.  For historic reasons, we had three
    implementations of it.  These are all consolidated into time/ftime.c,
    and then the function is deprecated.
    
    For some reason, the implementation of ftime in terms of gettimeofday
    was rounding rather than truncating microseconds to milliseconds.  In
    all the other places where we use a higher-resolution time function to
    implement a lower-resolution one, we truncate.  ftime is changed to
    match, just for tidiness' sake.
    
    Like gettimeofday, ftime tries to report the time zone, and using that
    information is always a bug.  This patch dummies out the reported
    timezone information; the timezone and dstflag fields of the
    returned "struct timeb" will always be zero.
    
    	* sysdeps/unix/bsd/ftime.c
    	* sysdeps/unix/sysv/linux/ftime.c: Remove file.
    
    	* time/ftime.c (ftime): Replace implementation with the code formerly
    	in sysdeps/unix/bsd/ftime.c, then change that code to use
    	__clock_gettime instead of __gettimeofday and to truncate rather than
    	rounding.  Always set the timezone and dstflag fields of the timebuf
    	argument to zero.
    
    	* time/sys/timeb.h (ftime): Add nonnull and deprecate attribute.
    	* time/tst-ftime.c (do_test): Handle ftime deprecation.

Diff:
---
 sysdeps/unix/bsd/ftime.c        | 40 ----------------------------------------
 sysdeps/unix/sysv/linux/ftime.c |  3 ---
 time/ftime.c                    | 26 +++++++++-----------------
 time/sys/timeb.h                |  3 ++-
 time/tst-ftime.c                |  7 +++++++
 5 files changed, 18 insertions(+), 61 deletions(-)

diff --git a/sysdeps/unix/bsd/ftime.c b/sysdeps/unix/bsd/ftime.c
deleted file mode 100644
index 3a1c6e9..0000000
--- a/sysdeps/unix/bsd/ftime.c
+++ /dev/null
@@ -1,40 +0,0 @@
-/* Copyright (C) 1994-2019 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 <sys/timeb.h>
-#include <sys/time.h>
-
-int
-ftime (struct timeb *timebuf)
-{
-  struct timeval tv;
-  struct timezone tz;
-
-  if (__gettimeofday (&tv, &tz) < 0)
-    return -1;
-
-  timebuf->time = tv.tv_sec;
-  timebuf->millitm = (tv.tv_usec + 500) / 1000;
-  if (timebuf->millitm == 1000)
-    {
-      ++timebuf->time;
-      timebuf->millitm = 0;
-    }
-  timebuf->timezone = tz.tz_minuteswest;
-  timebuf->dstflag = tz.tz_dsttime;
-  return 0;
-}
diff --git a/sysdeps/unix/sysv/linux/ftime.c b/sysdeps/unix/sysv/linux/ftime.c
deleted file mode 100644
index 5a5949f..0000000
--- a/sysdeps/unix/sysv/linux/ftime.c
+++ /dev/null
@@ -1,3 +0,0 @@
-/* Linux defines the ftime system call but doesn't actually implement
-   it.  Use the BSD implementation.  */
-#include <sysdeps/unix/bsd/ftime.c>
diff --git a/time/ftime.c b/time/ftime.c
index 6c2a256..a0ff5e5 100644
--- a/time/ftime.c
+++ b/time/ftime.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 1994-2019 Free Software Foundation, Inc.
+/* Deprecated return date and time.
+   Copyright (C) 1994-2019 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
@@ -15,27 +16,18 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <time.h>
 #include <sys/timeb.h>
+#include <time.h>
 
 int
 ftime (struct timeb *timebuf)
 {
-  int save = errno;
-  struct tm tp;
-
-  __set_errno (0);
-  if (time (&timebuf->time) == (time_t) -1 && errno != 0)
-    return -1;
-  timebuf->millitm = 0;
-
-  if (__localtime_r (&timebuf->time, &tp) == NULL)
-    return -1;
-
-  timebuf->timezone = tp.tm_gmtoff / 60;
-  timebuf->dstflag = tp.tm_isdst;
+  struct timespec ts;
+  __clock_gettime (CLOCK_REALTIME, &ts);
 
-  __set_errno (save);
+  timebuf->time = ts.tv_sec;
+  timebuf->millitm = ts.tv_nsec / 1000000;
+  timebuf->timezone = 0;
+  timebuf->dstflag = 0;
   return 0;
 }
diff --git a/time/sys/timeb.h b/time/sys/timeb.h
index 6333e80..fa4daa0 100644
--- a/time/sys/timeb.h
+++ b/time/sys/timeb.h
@@ -36,7 +36,8 @@ struct timeb
 
 /* Fill in TIMEBUF with information about the current time.  */
 
-extern int ftime (struct timeb *__timebuf);
+extern int ftime (struct timeb *__timebuf)
+  __nonnull ((1)) __attribute_deprecated__;
 
 __END_DECLS
 
diff --git a/time/tst-ftime.c b/time/tst-ftime.c
index 65b753d..e1d5e26 100644
--- a/time/tst-ftime.c
+++ b/time/tst-ftime.c
@@ -18,6 +18,7 @@
 
 #include <sys/timeb.h>
 #include <stdio.h>
+#include <libc-diag.h>
 
 static int
 do_test (void)
@@ -29,12 +30,18 @@ do_test (void)
     {
       prev = curr;
 
+      /* ftime was deprecated on 2.31.  */
+      DIAG_PUSH_NEEDS_COMMENT;
+      DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wdeprecated-declarations");
+
       if (ftime (&curr))
         {
           printf ("ftime returned an error\n");
           return 1;
         }
 
+      DIAG_POP_NEEDS_COMMENT;
+
       if (curr.time < prev.time)
         {
           printf ("ftime's time flowed backwards\n");