winsup/utils/tzset.c

   1 /* tzset.c: Convert current Windows timezone to POSIX timezone information.
   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 <errno.h>
  10 #include <stdio.h>
  11 #include <inttypes.h>
  12 #include <wchar.h>
  13 #include <locale.h>
  14 #include <getopt.h>
  15 #include <cygwin/version.h>
  16 #include <windows.h>
  17
  18 #ifndef GEOID_NOT_AVAILABLE
  19 #define GEOID_NOT_AVAILABLE -1
  20 #endif
  21
  22 /* The auto-generated tzmap.h contains the mapping table from Windows timezone
  23    and country per ISO 3166-1 to POSIX timezone.  For more info, see the file
  24    itself. */
  25 #include "tzmap.h"
  26
  27 #define TZMAP_SIZE (sizeof tzmap / sizeof tzmap[0])
  28
  29 static struct option longopts[] =
  30 {
  31   {"help", no_argument, NULL, 'h' },
  32   {"version", no_argument, NULL, 'V'},
  33   {NULL, 0, NULL, 0}
  34 };
  35
  36 static char opts[] = "hV";
  37
  38 #define REG_TZINFO L"SYSTEM\\CurrentControlSet\\Control\\TimeZoneInformation"
  39 #define REG_TZDB L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones"
  40
  41 static inline HKEY
  42 reg_open (HKEY pkey, PCWSTR path, const char *msg)
  43 {
  44   LONG ret;
  45   HKEY hkey;
  46
  47   ret = RegOpenKeyExW (pkey, path, 0, KEY_READ, &hkey);
  48   if (ret == ERROR_SUCCESS)
  49     return hkey;
  50   if (msg)
  51     fprintf (stderr, "%s: cannot open registry %s, error code %" PRIu32 "\n",
  52              program_invocation_short_name, msg, (unsigned int) ret);
  53   return NULL;
  54 }
  55
  56 /* For symmetry */
  57 #define reg_close(hkey) RegCloseKey(hkey)
  58
  59 static inline BOOL
  60 reg_query (HKEY hkey, PCWSTR value, PWCHAR buf, DWORD size, const char *msg)
  61 {
  62   LONG ret;
  63   DWORD type;
  64
  65   ret = RegQueryValueExW (hkey, value, 0, &type, (LPBYTE) buf, &size);
  66   if (ret == ERROR_SUCCESS)
  67     return TRUE;
  68   if (msg)
  69     fprintf (stderr, "%s: cannot query registry %s, error code %" PRIu32 "\n",
  70              program_invocation_short_name, msg, (unsigned int) ret);
  71   return FALSE;
  72 }
  73
  74 static inline BOOL
  75 reg_enum (HKEY hkey, int idx, PWCHAR name, DWORD size)
  76 {
  77   return RegEnumKeyExW (hkey, idx, name, &size, NULL, NULL, NULL, NULL)
  78          == ERROR_SUCCESS;
  79 }
  80
  81 static void __attribute__ ((__noreturn__))
  82 usage (FILE *stream)
  83 {
  84   fprintf (stream, ""
  85   "Usage: %1$s [OPTION]\n"
  86   "\n"
  87   "Print POSIX-compatible timezone ID from current Windows timezone setting\n"
  88   "\n"
  89   "Options:\n"
  90   "  -h, --help               output usage information and exit.\n"
  91   "  -V, --version            output version information and exit.\n"
  92   "\n"
  93   "Use %1$s to set your TZ variable. In POSIX-compatible shells like bash,\n"
  94   "dash, mksh, or zsh:\n"
  95   "\n"
  96   "      export TZ=$(%1$s)\n"
  97   "\n"
  98   "In csh-compatible shells like tcsh:\n"
  99   "\n"
 100   "      setenv TZ `%1$s`\n"
 101   "\n", program_invocation_short_name);
 102   exit (stream == stdout ? 0 : 1);
 103 };
 104
 105 static void
 106 print_version ()
 107 {
 108   printf ("tzset (cygwin) %d.%d.%d\n"
 109           "POSIX-timezone generator\n"
 110           "Copyright (C) 2012 - %s Cygwin Authors\n"
 111           "This is free software; see the source for copying conditions.  There is NO\n"
 112           "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n",
 113           CYGWIN_VERSION_DLL_MAJOR / 1000,
 114           CYGWIN_VERSION_DLL_MAJOR % 1000,
 115           CYGWIN_VERSION_DLL_MINOR,
 116           strrchr (__DATE__, ' ') + 1);
 117 }
 118
 119 int
 120 main (int argc, char **argv)
 121 {
 122   BOOL ret;
 123   HKEY hkey, skey;
 124   WCHAR keyname[256], stdname[256], std2name[256], country[10], *spc;
 125   GEOID geo;
 126   int opt, idx, gotit = -1;
 127
 128   setlocale (LC_ALL, "");
 129   while ((opt = getopt_long (argc, argv, opts, longopts, NULL)) != EOF)
 130     switch (opt)
 131       {
 132       case 'h':
 133         usage (stdout);
 134       case 'V':
 135         print_version ();
 136         return 0;
 137       default:
 138         fprintf (stderr, "Try `%s --help' for more information.\n",
 139                  program_invocation_short_name);
 140         return 1;
 141       }
 142   if (optind < argc)
 143     usage (stderr);
 144
 145   /* First fetch current timezone information from registry. */
 146   hkey = reg_open (HKEY_LOCAL_MACHINE, REG_TZINFO, "timezone information");
 147   if (!hkey)
 148     return 1;
 149   /* Vista introduced the TimeZoneKeyName value, which simplifies the
 150      job a lot. */
 151   if (!reg_query (hkey, L"TimeZoneKeyName", keyname, sizeof keyname, NULL))
 152     {
 153       /* Pre-Vista we have a lot more to do.  First fetch the name of the
 154          Standard (non-DST) timezone.  If we can't get that, give up. */
 155       if (!reg_query (hkey, L"StandardName", stdname, sizeof stdname,
 156                       "timezone information"))
 157         {
 158           reg_close (hkey);
 159           return 1;
 160         }
 161       reg_close (hkey);
 162       /* Now open the timezone database registry key.  Every subkey is a
 163          timezone.  The key name is what we're after, but to find the right
 164          one, we have to compare the name of the previously fetched
 165          "StandardName" with the "Std" value in the timezone info... */
 166       hkey = reg_open (HKEY_LOCAL_MACHINE, REG_TZDB, "timezone database");
 167       if (!hkey)
 168         return 1;
 169       for (idx = 0; reg_enum (hkey, idx, keyname, sizeof keyname); ++idx)
 170         {
 171           skey = reg_open (hkey, keyname, NULL);
 172           if (skey)
 173             {
 174               /* ...however, on MUI-enabled machines, the names are not stored
 175                  directly in the above StandardName, rather it is a resource
 176                  pointer into tzres.dll.  This is stored in MUI_Std.
 177                  Fortunately it's easy to recognize this situation: If
 178                  StandardName starts with @, it's a resource pointer, otherwise
 179                  it's the cleartext value. */
 180               ret = reg_query (skey, stdname[0] == L'@' ? L"MUI_Std" : L"Std",
 181                                std2name, sizeof std2name, NULL);
 182               reg_close (skey);
 183               if (ret && !wcscmp (stdname, std2name))
 184                 break;
 185             }
 186         }
 187     }
 188   reg_close (hkey);
 189
 190   /* We fetch the current Geo-location of the user and convert it to an
 191      ISO 3166-1 compatible nation code. */
 192   *country = L'\0';
 193   geo = GetUserGeoID (GEOCLASS_NATION);
 194   if (geo != GEOID_NOT_AVAILABLE)
 195     GetGeoInfoW (geo, GEO_ISO2, country, sizeof country / sizeof (*country), 0);
 196   /* If, for some reason, the Geo-location isn't available, we use the locale
 197      setting instead. */
 198   if (!*country)
 199     GetLocaleInfoW (LOCALE_USER_DEFAULT, LOCALE_SISO3166CTRYNAME,
 200                     country, sizeof country);
 201
 202   /* Now iterate over the mapping table and find the right entry. */
 203   for (idx = 0; idx < TZMAP_SIZE; ++idx)
 204     {
 205       if (!wcscasecmp (keyname, tzmap[idx].win_tzkey))
 206         {
 207           if (gotit < 0)
 208             gotit = idx;
 209           if (!wcscasecmp (country, tzmap[idx].country))
 210             break;
 211         }
 212       else if (gotit >= 0)
 213         {
 214           idx = gotit;
 215           break;
 216         }
 217     }
 218   if (idx >= TZMAP_SIZE)
 219     {
 220       if (gotit < 0)
 221         {
 222           fprintf (stderr,
 223                    "%s: can't find matching POSIX timezone for "
 224                    "Windows timezone \"%ls\"\n",
 225                    program_invocation_short_name, keyname);
 226           return 1;
 227         }
 228       idx = gotit;
 229     }
 230   /* Got one.  Print it.
 231      Note: The tzmap array is in the R/O data section on x86_64.  Don't
 232            try to overwrite the space, as the code did originally. */
 233   spc = wcschr (tzmap[idx].posix_tzid, L' ');
 234   if (!spc)
 235     spc = wcschr (tzmap[idx].posix_tzid, L'\0');
 236   printf ("%.*ls\n", (int) (spc - tzmap[idx].posix_tzid), tzmap[idx].posix_tzid);
 237   return 0;
 238 }