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