src/port/win32setlocale.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * win32setlocale.c
   4  *              Wrapper to work around bugs in Windows setlocale() implementation
   5  *
   6  * Copyright (c) 2011-2021, PostgreSQL Global Development Group
   7  *
   8  * IDENTIFICATION
   9  *        src/port/win32setlocale.c
  10  *
  11  *
  12  * The setlocale() function in Windows is broken in two ways. First, it
  13  * has a problem with locale names that have a dot in the country name. For
  14  * example:
  15  *
  16  * "Chinese (Traditional)_Hong Kong S.A.R..950"
  17  *
  18  * For some reason, setlocale() doesn't accept that as argument, even though
  19  * setlocale(LC_ALL, NULL) returns exactly that. Fortunately, it accepts
  20  * various alternative names for such countries, so to work around the broken
  21  * setlocale() function, we map the troublemaking locale names to accepted
  22  * aliases, before calling setlocale().
  23  *
  24  * The second problem is that the locale name for "Norwegian (Bokm&aring;l)"
  25  * contains a non-ASCII character. That's problematic, because it's not clear
  26  * what encoding the locale name itself is supposed to be in, when you
  27  * haven't yet set a locale. Also, it causes problems when the cluster
  28  * contains databases with different encodings, as the locale name is stored
  29  * in the pg_database system catalog. To work around that, when setlocale()
  30  * returns that locale name, map it to a pure-ASCII alias for the same
  31  * locale.
  32  *-------------------------------------------------------------------------
  33  */
  34
  35 #include "c.h"
  36
  37 #undef setlocale
  38
  39 struct locale_map
  40 {
  41         /*
  42          * String in locale name to replace. Can be a single string (end is NULL),
  43          * or separate start and end strings. If two strings are given, the locale
  44          * name must contain both of them, and everything between them is
  45          * replaced. This is used for a poor-man's regexp search, allowing
  46          * replacement of "start.*end".
  47          */
  48         const char *locale_name_start;
  49         const char *locale_name_end;
  50
  51         const char *replacement;        /* string to replace the match with */
  52 };
  53
  54 /*
  55  * Mappings applied before calling setlocale(), to the argument.
  56  */
  57 static const struct locale_map locale_map_argument[] = {
  58         /*
  59          * "HKG" is listed here:
  60          * http://msdn.microsoft.com/en-us/library/cdax410z%28v=vs.71%29.aspx
  61          * (Country/Region Strings).
  62          *
  63          * "ARE" is the ISO-3166 three-letter code for U.A.E. It is not on the
  64          * above list, but seems to work anyway.
  65          */
  66         {"Hong Kong S.A.R.", NULL, "HKG"},
  67         {"U.A.E.", NULL, "ARE"},
  68
  69         /*
  70          * The ISO-3166 country code for Macau S.A.R. is MAC, but Windows doesn't
  71          * seem to recognize that. And Macau isn't listed in the table of accepted
  72          * abbreviations linked above. Fortunately, "ZHM" seems to be accepted as
  73          * an alias for "Chinese (Traditional)_Macau S.A.R..950". I'm not sure
  74          * where "ZHM" comes from, must be some legacy naming scheme. But hey, it
  75          * works.
  76          *
  77          * Note that unlike HKG and ARE, ZHM is an alias for the *whole* locale
  78          * name, not just the country part.
  79          *
  80          * Some versions of Windows spell it "Macau", others "Macao".
  81          */
  82         {"Chinese (Traditional)_Macau S.A.R..950", NULL, "ZHM"},
  83         {"Chinese_Macau S.A.R..950", NULL, "ZHM"},
  84         {"Chinese (Traditional)_Macao S.A.R..950", NULL, "ZHM"},
  85         {"Chinese_Macao S.A.R..950", NULL, "ZHM"},
  86         {NULL, NULL, NULL}
  87 };
  88
  89 /*
  90  * Mappings applied after calling setlocale(), to its return value.
  91  */
  92 static const struct locale_map locale_map_result[] = {
  93         /*
  94          * "Norwegian (Bokm&aring;l)" locale name contains the a-ring character.
  95          * Map it to a pure-ASCII alias.
  96          *
  97          * It's not clear what encoding setlocale() uses when it returns the
  98          * locale name, so to play it safe, we search for "Norwegian (Bok*l)".
  99          *
 100          * Just to make life even more complicated, some versions of Windows spell
 101          * the locale name without parentheses.  Translate that too.
 102          */
 103         {"Norwegian (Bokm", "l)_Norway", "Norwegian_Norway"},
 104         {"Norwegian Bokm", "l_Norway", "Norwegian_Norway"},
 105         {NULL, NULL, NULL}
 106 };
 107
 108 #define MAX_LOCALE_NAME_LEN             100
 109
 110 static const char *
 111 map_locale(const struct locale_map *map, const char *locale)
 112 {
 113         static char aliasbuf[MAX_LOCALE_NAME_LEN];
 114         int                     i;
 115
 116         /* Check if the locale name matches any of the problematic ones. */
 117         for (i = 0; map[i].locale_name_start != NULL; i++)
 118         {
 119                 const char *needle_start = map[i].locale_name_start;
 120                 const char *needle_end = map[i].locale_name_end;
 121                 const char *replacement = map[i].replacement;
 122                 char       *match;
 123                 char       *match_start = NULL;
 124                 char       *match_end = NULL;
 125
 126                 match = strstr(locale, needle_start);
 127                 if (match)
 128                 {
 129                         /*
 130                          * Found a match for the first part. If this was a two-part
 131                          * replacement, find the second part.
 132                          */
 133                         match_start = match;
 134                         if (needle_end)
 135                         {
 136                                 match = strstr(match_start + strlen(needle_start), needle_end);
 137                                 if (match)
 138                                         match_end = match + strlen(needle_end);
 139                                 else
 140                                         match_start = NULL;
 141                         }
 142                         else
 143                                 match_end = match_start + strlen(needle_start);
 144                 }
 145
 146                 if (match_start)
 147                 {
 148                         /* Found a match. Replace the matched string. */
 149                         int                     matchpos = match_start - locale;
 150                         int                     replacementlen = strlen(replacement);
 151                         char       *rest = match_end;
 152                         int                     restlen = strlen(rest);
 153
 154                         /* check that the result fits in the static buffer */
 155                         if (matchpos + replacementlen + restlen + 1 > MAX_LOCALE_NAME_LEN)
 156                                 return NULL;
 157
 158                         memcpy(&aliasbuf[0], &locale[0], matchpos);
 159                         memcpy(&aliasbuf[matchpos], replacement, replacementlen);
 160                         /* includes null terminator */
 161                         memcpy(&aliasbuf[matchpos + replacementlen], rest, restlen + 1);
 162
 163                         return aliasbuf;
 164                 }
 165         }
 166
 167         /* no match, just return the original string */
 168         return locale;
 169 }
 170
 171 char *
 172 pgwin32_setlocale(int category, const char *locale)
 173 {
 174         const char *argument;
 175         char       *result;
 176
 177         if (locale == NULL)
 178                 argument = NULL;
 179         else
 180                 argument = map_locale(locale_map_argument, locale);
 181
 182         /* Call the real setlocale() function */
 183         result = setlocale(category, argument);
 184
 185         /*
 186          * setlocale() is specified to return a "char *" that the caller is
 187          * forbidden to modify, so casting away the "const" is innocuous.
 188          */
 189         if (result)
 190                 result = unconstify(char *, map_locale(locale_map_result, result));
 191
 192         return result;
 193 }