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.

Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
powerpc64-linux-gnu, and powerpc-linux-gnu.

Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Lukasz Majewski <lukma@denx.de>

3 files changed, 18 insertions, 18 deletions

diff --git a/time/ftime.c b/time/ftime.c
index 8bedc0d91e..b4bd58ecef 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
    <https://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 b958dc3e4a..5c16f79da2 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 4b7e90cc03..39d94a1b26 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");