1/* Provide gettimeofday for systems that don't have it or for which it's broken.
2
3   Copyright (C) 2001, 2002, 2003, 2005, 2006, 2007 Free Software
4   Foundation, Inc.
5
6   This program is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 2, or (at your option)
9   any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program; if not, write to the Free Software Foundation,
18   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
19
20/* written by Jim Meyering */
21
22#include <config.h>
23
24/* Specification.  */
25#include <sys/time.h>
26
27#include <time.h>
28
29#if HAVE_SYS_TIMEB_H
30# include <sys/timeb.h>
31#endif
32
33#if GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME
34
35/* Work around the bug in some systems whereby gettimeofday clobbers
36   the static buffer that localtime uses for its return value.  The
37   gettimeofday function from Mac OS X 10.0.4 (i.e., Darwin 1.3.7) has
38   this problem.  The tzset replacement is necessary for at least
39   Solaris 2.5, 2.5.1, and 2.6.  */
40
41static struct tm tm_zero_buffer;
42static struct tm *localtime_buffer_addr = &tm_zero_buffer;
43
44/* This is a wrapper for localtime.  It is used only on systems for which
45   gettimeofday clobbers the static buffer used for localtime's result.
46
47   On the first call, record the address of the static buffer that
48   localtime uses for its result.  */
49
50struct tm *
51localtime (time_t const *timep)
52{
53#undef localtime
54  extern struct tm *localtime (time_t const *);
55  struct tm *tm = localtime (timep);
56
57  if (localtime_buffer_addr == &tm_zero_buffer)
58    localtime_buffer_addr = tm;
59
60  return tm;
61}
62
63/* Same as above, since gmtime and localtime use the same buffer.  */
64struct tm *
65gmtime (time_t const *timep)
66{
67#undef gmtime
68  extern struct tm *gmtime (time_t const *);
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/* This is a wrapper for tzset, for systems on which tzset may clobber
81   the static buffer used for localtime's result.  */
82void
83tzset (void)
84{
85#undef tzset
86  extern void tzset (void);
87
88  /* Save and restore the contents of the buffer used for localtime's
89     result around the call to tzset.  */
90  struct tm save = *localtime_buffer_addr;
91  tzset ();
92  *localtime_buffer_addr = save;
93}
94#endif
95
96/* This is a wrapper for gettimeofday.  It is used only on systems
97   that lack this function, or whose implementation of this function
98   causes problems.  */
99
100int
101rpl_gettimeofday (struct timeval *restrict tv, void *restrict tz)
102{
103#undef gettimeofday
104#if HAVE_GETTIMEOFDAY
105# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
106  /* Save and restore the contents of the buffer used for localtime's
107     result around the call to gettimeofday.  */
108  struct tm save = *localtime_buffer_addr;
109# endif
110
111  int result = gettimeofday (tv, tz);
112
113# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
114  *localtime_buffer_addr = save;
115# endif
116
117  return result;
118
119#else
120
121# if HAVE__FTIME
122
123  struct _timeb timebuf;
124  _ftime (&timebuf);
125  tv->tv_sec = timebuf.time;
126  tv->tv_usec = timebuf.millitm * 1000;
127
128# else
129
130#  if !defined OK_TO_USE_1S_CLOCK
131#   error "Only 1-second nominal clock resolution found.  Is that intended?" \
132          "If so, compile with the -DOK_TO_USE_1S_CLOCK option."
133#  endif
134  tv->tv_sec = time (NULL);
135  tv->tv_usec = 0;
136
137# endif
138
139  return 0;
140
141#endif
142}
143