1/* Provide gettimeofday for systems that don't have it or for which it's broken.
2
3   Copyright (C) 2001-2003, 2005-2007, 2009-2014 Free Software Foundation, Inc.
4
5   This program is free software; you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3, or (at your option)
8   any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
17
18/* written by Jim Meyering */
19
20#include <config.h>
21
22/* Specification.  */
23#include <sys/time.h>
24
25#include <time.h>
26
27#if HAVE_SYS_TIMEB_H
28# include <sys/timeb.h>
29#endif
30
31#if GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME
32
33/* Work around the bug in some systems whereby gettimeofday clobbers
34   the static buffer that localtime uses for its return value.  The
35   gettimeofday function from Mac OS X 10.0.4 (i.e., Darwin 1.3.7) has
36   this problem.  The tzset replacement is necessary for at least
37   Solaris 2.5, 2.5.1, and 2.6.  */
38
39static struct tm tm_zero_buffer;
40static struct tm *localtime_buffer_addr = &tm_zero_buffer;
41
42# undef localtime
43extern struct tm *localtime (time_t const *);
44
45# undef gmtime
46extern struct tm *gmtime (time_t const *);
47
48/* This is a wrapper for localtime.  It is used only on systems for which
49   gettimeofday clobbers the static buffer used for localtime's result.
50
51   On the first call, record the address of the static buffer that
52   localtime uses for its result.  */
53
54struct tm *
55rpl_localtime (time_t const *timep)
56{
57  struct tm *tm = localtime (timep);
58
59  if (localtime_buffer_addr == &tm_zero_buffer)
60    localtime_buffer_addr = tm;
61
62  return tm;
63}
64
65/* Same as above, since gmtime and localtime use the same buffer.  */
66struct tm *
67rpl_gmtime (time_t const *timep)
68{
69  struct tm *tm = gmtime (timep);
70
71  if (localtime_buffer_addr == &tm_zero_buffer)
72    localtime_buffer_addr = tm;
73
74  return tm;
75}
76
77#endif /* GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME */
78
79#if TZSET_CLOBBERS_LOCALTIME
80
81# undef tzset
82extern void tzset (void);
83
84/* This is a wrapper for tzset, for systems on which tzset may clobber
85   the static buffer used for localtime's result.  */
86void
87rpl_tzset (void)
88{
89  /* Save and restore the contents of the buffer used for localtime's
90     result around the call to tzset.  */
91  struct tm save = *localtime_buffer_addr;
92  tzset ();
93  *localtime_buffer_addr = save;
94}
95#endif
96
97/* This is a wrapper for gettimeofday.  It is used only on systems
98   that lack this function, or whose implementation of this function
99   causes problems.  */
100
101int
102gettimeofday (struct timeval *restrict tv, void *restrict tz)
103{
104#undef gettimeofday
105#if HAVE_GETTIMEOFDAY
106# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
107  /* Save and restore the contents of the buffer used for localtime's
108     result around the call to gettimeofday.  */
109  struct tm save = *localtime_buffer_addr;
110# endif
111
112# if defined timeval /* 'struct timeval' overridden by gnulib?  */
113#  undef timeval
114  struct timeval otv;
115  int result = gettimeofday (&otv, (struct timezone *) tz);
116  if (result == 0)
117    {
118      tv->tv_sec = otv.tv_sec;
119      tv->tv_usec = otv.tv_usec;
120    }
121# else
122  int result = gettimeofday (tv, (struct timezone *) tz);
123# endif
124
125# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
126  *localtime_buffer_addr = save;
127# endif
128
129  return result;
130
131#else
132
133# if HAVE__FTIME
134
135  struct _timeb timebuf;
136  _ftime (&timebuf);
137  tv->tv_sec = timebuf.time;
138  tv->tv_usec = timebuf.millitm * 1000;
139
140# else
141
142#  if !defined OK_TO_USE_1S_CLOCK
143#   error "Only 1-second nominal clock resolution found.  Is that intended?" \
144          "If so, compile with the -DOK_TO_USE_1S_CLOCK option."
145#  endif
146  tv->tv_sec = time (NULL);
147  tv->tv_usec = 0;
148
149# endif
150
151  return 0;
152
153#endif
154}
155