winsup/cygwin/tzcode/localtime_wrapper.c

   1 /* localtime.cc: Wrapper of NetBSD tzcode support for Cygwin. See README file.
   2
   3 This file is part of Cygwin.
   4
   5 This software is a copyrighted work licensed under the terms of the
   6 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
   7 details. */
   8
   9 #include "../winsup.h"
  10 #include "../sync.h"
  11 #include "../include/cygwin/version.h"
  12 #include "tz_posixrules.h"
  13
  14 static NO_COPY muto tzset_guard;
  15
  16 // Convert these NetBSD rwlock ops into Cygwin muto ops
  17 #define rwlock_wrlock(X) tzset_guard.init("tzset_guard")->acquire()
  18 #define rwlock_unlock(X) tzset_guard.release()
  19
  20 // Set these NetBSD-related option #defines appropriately for Cygwin
  21 //#define STD_INSPIRED  // early-include private.h below does this
  22 #define lint
  23 #define HAVE_POSIX_DECLS 0
  24 #define USG_COMPAT 1
  25 #define NO_ERROR_IN_DST_GAP
  26 #define state __state
  27
  28 // Turn a specific known kind of const parameter into non-const
  29 #define __UNCONST(X) ((char *) (X))
  30
  31 // Turn off these NetBSD audit-related definitions
  32 #define __aconst
  33 #define _DIAGASSERT(X)
  34
  35 // Supply this Cygwin-specific function in advance of its use in localtime.c
  36 static char *
  37 tzgetwintzi (char *wildabbr, char *outbuf)
  38 {
  39     TIME_ZONE_INFORMATION tzi;
  40     char *cp, *dst;
  41     wchar_t *wsrc;
  42     div_t d;
  43
  44     GetTimeZoneInformation (&tzi);
  45     dst = cp = outbuf;
  46     for (wsrc = tzi.StandardName; *wsrc; wsrc++)
  47         if (*wsrc >= L'A' && *wsrc <= L'Z')
  48             *dst++ = *wsrc;
  49     if ((dst - cp) < 3)
  50       {
  51         /* In non-english Windows, converted tz.StandardName
  52            may not contain a valid standard timezone name. */
  53         strcpy (cp, wildabbr);
  54         cp += strlen (wildabbr);
  55       }
  56     else
  57         cp = dst;
  58     d = div (tzi.Bias + tzi.StandardBias, 60);
  59     __small_sprintf (cp, "%d", d.quot);
  60     if (d.rem)
  61         __small_sprintf (cp = strchr (cp, 0), ":%d", abs (d.rem));
  62     if (tzi.StandardDate.wMonth)
  63       {
  64         cp = strchr (cp, 0);
  65         dst = cp;
  66         for (wsrc = tzi.DaylightName; *wsrc; wsrc++)
  67             if (*wsrc >= L'A' && *wsrc <= L'Z')
  68                 *dst++ = *wsrc;
  69         if ((dst - cp) < 3)
  70           {
  71             /* In non-english Windows, converted tz.DaylightName
  72                may not contain a valid daylight timezone name. */
  73             strcpy (cp, wildabbr);
  74             cp += strlen (wildabbr);
  75           }
  76         else
  77             cp = dst;
  78         d = div (tzi.Bias + tzi.DaylightBias, 60);
  79         __small_sprintf (cp, "%d", d.quot);
  80         if (d.rem)
  81             __small_sprintf (cp = strchr (cp, 0), ":%d", abs (d.rem));
  82         cp = strchr (cp, 0);
  83         __small_sprintf (cp = strchr (cp, 0), ",M%d.%d.%d/%d",
  84                          tzi.DaylightDate.wMonth,
  85                          tzi.DaylightDate.wDay,
  86                          tzi.DaylightDate.wDayOfWeek,
  87                          tzi.DaylightDate.wHour);
  88         if (tzi.DaylightDate.wMinute || tzi.DaylightDate.wSecond)
  89             __small_sprintf (cp = strchr (cp, 0), ":%d",
  90                              tzi.DaylightDate.wMinute);
  91         if (tzi.DaylightDate.wSecond)
  92             __small_sprintf (cp = strchr (cp, 0), ":%d",
  93                              tzi.DaylightDate.wSecond);
  94         cp = strchr (cp, 0);
  95         __small_sprintf (cp = strchr (cp, 0), ",M%d.%d.%d/%d",
  96                          tzi.StandardDate.wMonth,
  97                          tzi.StandardDate.wDay,
  98                          tzi.StandardDate.wDayOfWeek,
  99                          tzi.StandardDate.wHour);
 100         if (tzi.StandardDate.wMinute || tzi.StandardDate.wSecond)
 101             __small_sprintf (cp = strchr (cp, 0), ":%d",
 102                              tzi.StandardDate.wMinute);
 103         if (tzi.StandardDate.wSecond)
 104             __small_sprintf (cp = strchr (cp, 0), ":%d",
 105                              tzi.StandardDate.wSecond);
 106       }
 107     /* __small_printf ("TZ deduced as `%s'\n", outbuf); */
 108     return outbuf;
 109 }
 110
 111 // Get ready to wrap NetBSD's localtime.c
 112 #ifdef __cplusplus
 113 extern "C" {
 114 #endif
 115
 116 // Pull these in early to catch any small issues before the real test
 117 #include "private.h"
 118 #include "tzfile.h"
 119
 120 /* Some NetBSD differences were too difficult to work around..
 121    so #include a patched copy of localtime.c rather than the NetBSD original.
 122    Here is a list of the patches...
 123    (1) fix an erroneous decl of tzdirslash size (flagged by g++)
 124    (2) add conditional call to Cygwin's tzgetwintzi() from tzsetlcl()
 125    (3) add Cygwin's historical "posixrules" support to tzloadbody()
 126 */
 127 #include "localtime.c.patched"
 128
 129 #ifdef __cplusplus
 130 }
 131 #endif
 132
 133 // Don't forget these Cygwin-specific additions from this point to EOF
 134 EXPORT_ALIAS (tzset_unlocked, _tzset_unlocked)
 135
 136 extern "C" long
 137 __cygwin_gettzoffset (const struct tm *tmp)
 138 {
 139 #ifdef TM_GMTOFF
 140     if (CYGWIN_VERSION_CHECK_FOR_EXTRA_TM_MEMBERS)
 141         return tmp->TM_GMTOFF;
 142 #endif /* defined TM_GMTOFF */
 143     __tzinfo_type *tz = __gettzinfo ();
 144     /* The sign of this is exactly opposite the envvar TZ.  We
 145        could directly use the global _timezone for tm_isdst==0,
 146        but have to use __tzrule for daylight savings.  */
 147     long offset = -tz->__tzrule[tmp->tm_isdst > 0].offset;
 148     return offset;
 149 }
 150
 151 extern "C" const char *
 152 __cygwin_gettzname (const struct tm *tmp)
 153 {
 154 #ifdef TM_ZONE
 155     if (CYGWIN_VERSION_CHECK_FOR_EXTRA_TM_MEMBERS)
 156         return tmp->TM_ZONE;
 157 #endif
 158     return _tzname[tmp->tm_isdst > 0];
 159 }