glibc/locale/setlocale.c

/* Copyright (C) 1991, 1992, 1995, 1996, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <alloca.h>
#include <argz.h>
#include <errno.h>
#include <bits/libc-lock.h>
#include <locale.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "localeinfo.h"

/* For each category declare two external variables (with weak references):
     extern const struct locale_data *_nl_current_CATEGORY;
   This points to the current locale's in-core data for CATEGORY.
     extern const struct locale_data _nl_C_CATEGORY;
   This contains the built-in "C"/"POSIX" locale's data for CATEGORY.
   Both are weak references; if &_nl_current_CATEGORY is zero,
   then nothing is using the locale data.  */
#define DEFINE_CATEGORY(category, category_name, items, a, b, c, d) \
extern struct locale_data *_nl_current_##category;			      \
extern struct locale_data _nl_C_##category;				      \
weak_extern (_nl_current_##category) weak_extern (_nl_C_##category)
#include "categories.def"
#undef	DEFINE_CATEGORY

/* Array indexed by category of pointers to _nl_current_CATEGORY slots.
   Elements are zero for categories whose data is never used.  */
static struct locale_data * *const _nl_current[] =
  {
#define DEFINE_CATEGORY(category, category_name, items, a, b, c, d) \
    [category] = &_nl_current_##category,
#include "categories.def"
#undef	DEFINE_CATEGORY
    /* We need this additional element to simplify the code.  It must
       simply be != NULL.  */
    [LC_ALL] = (struct locale_data **) ~0ul
  };

/* Array indexed by category of pointers to _nl_C_CATEGORY slots.
   Elements are zero for categories whose data is never used.  */
struct locale_data *const _nl_C[] =
  {
#define DEFINE_CATEGORY(category, category_name, items, a, b, c, d) \
    [category] = &_nl_C_##category,
#include "categories.def"
#undef	DEFINE_CATEGORY
  };


/* Define an array of category names (also the environment variable names),
   indexed by integral category.  */
const char *const _nl_category_names[] =
  {
#define DEFINE_CATEGORY(category, category_name, items, a, b, c, d) \
    [category] = category_name,
#include "categories.def"
#undef	DEFINE_CATEGORY
    [LC_ALL] = "LC_ALL"
  };
/* An array of their lengths, for convenience.  */
const size_t _nl_category_name_sizes[] =
  {
#define DEFINE_CATEGORY(category, category_name, items, a, b, c, d) \
    [category] = sizeof (category_name) - 1,
#include "categories.def"
#undef	DEFINE_CATEGORY
    [LC_ALL] = sizeof ("LC_ALL") - 1
  };


/* Declare the postload functions used below.  */
#undef	NO_POSTLOAD
#define NO_POSTLOAD _nl_postload_ctype /* Harmless thing known to exist.  */
#define DEFINE_CATEGORY(category, category_name, items, postload, b, c, d) \
extern void postload (void);
#include "categories.def"
#undef	DEFINE_CATEGORY
#undef	NO_POSTLOAD

/* Define an array indexed by category of postload functions to call after
   loading and installing that category's data.  */
static void (*const _nl_category_postload[]) (void) =
  {
#define DEFINE_CATEGORY(category, category_name, items, postload, b, c, d) \
    [category] = postload,
#include "categories.def"
#undef	DEFINE_CATEGORY
  };


/* Name of current locale for each individual category.
   Each is malloc'd unless it is nl_C_name.  */
static const char *_nl_current_names[] =
  {
#define DEFINE_CATEGORY(category, category_name, items, a, b, c, d) \
    [category] = _nl_C_name,
#include "categories.def"
#undef	DEFINE_CATEGORY
    [LC_ALL] = _nl_C_name		/* For LC_ALL.  */
  };


/* Lock for protecting global data.  */
__libc_lock_define_initialized (, __libc_setlocale_lock)


/* Use this when we come along an error.  */
#define ERROR_RETURN							      \
  do {									      \
    __set_errno (EINVAL);						      \
    return NULL;							      \
  } while (0)


static inline char *
clever_copy (const char *string)
{
  size_t len;
  char *new;

  if (strcmp (string, "C") == 0 || strcmp (string, "POSIX") == 0)
    /* This return is dangerous because the returned string might be
       placed in read-only memory.  But everything should be set up to
       handle this case.  */
    return (char *) _nl_C_name;

  len = strlen (string) + 1;
  new = (char *) malloc (len);
  return new != NULL ? memcpy (new, string, len) : NULL;
}


/* Construct a new composite name.  */
static inline char *
new_composite_name (int category, const char *newnames[LC_ALL])
{
  size_t last_len;
  size_t cumlen = 0;
  int i;
  char *new, *p;
  int same = 1;

  for (i = 0; i < LC_ALL; ++i)
    {
      const char *name = (category == LC_ALL ? newnames[i] :
			  category == i ? newnames[0] :
			  _nl_current_names[i]);
      last_len = strlen (name);
      cumlen += _nl_category_name_sizes[i] + 1 + last_len + 1;
      if (i > 0 && same && strcmp (name, newnames[0]) != 0)
	same = 0;
    }

  if (same)
    {
      /* All the categories use the same name.  */
      if (strcmp (newnames[0], "C") == 0 || strcmp (newnames[0], "POSIX") == 0)
	return (char *) _nl_C_name;

      new = malloc (last_len + 1);

      return new == NULL ? NULL : memcpy (new, newnames[0], last_len + 1);
    }

  new = malloc (cumlen);
  if (new == NULL)
    return NULL;
  p = new;
  for (i = 0; i < LC_ALL; ++i)
    {
      /* Add "CATEGORY=NAME;" to the string.  */
      const char *name = (category == LC_ALL ? newnames[i] :
			  category == i ? newnames[0] :
			  _nl_current_names[i]);
      p = __stpcpy (p, _nl_category_names[i]);
      *p++ = '=';
      p = __stpcpy (p, name);
      *p++ = ';';
    }
  p[-1] = '\0';		/* Clobber the last ';'.  */
  return new;
}


/* Put NAME in _nl_current_names.  */
static inline void
setname (int category, const char *name)
{
  if (_nl_current_names[category] == name)
    return;

  if (_nl_current_names[category] != _nl_C_name)
    free ((void *) _nl_current_names[category]);

  _nl_current_names[category] = name;
}


/* Put DATA in *_nl_current[CATEGORY].  */
static inline void
setdata (int category, struct locale_data *data)
{
  if (_nl_current[category] != NULL)
    {
      *_nl_current[category] = data;
      if (_nl_category_postload[category])
	(*_nl_category_postload[category]) ();
    }
}


char *
setlocale (int category, const char *locale)
{
  char *locale_path;
  size_t locale_path_len;
  const char *locpath_var;
  char *composite;

  /* Sanity check for CATEGORY argument.  */
  if (category < 0 || category > LC_ALL)
    ERROR_RETURN;

  /* Does user want name of current locale?  */
  if (locale == NULL)
    return (char *) _nl_current_names[category];

  if (strcmp (locale, _nl_current_names[category]) == 0)
    /* Changing to the same thing.  */
    return (char *) _nl_current_names[category];

  /* We perhaps really have to load some data.  So we determine the
     path in which to look for the data now.  The environment variable
     `LOCPATH' must only be used when the binary has no SUID or SGID
     bit set.  */
  locale_path = NULL;
  locale_path_len = 0;

  locpath_var = __secure_getenv ("LOCPATH");
  if (locpath_var != NULL && locpath_var[0] != '\0')
    if (__argz_create_sep (locpath_var, ':',
			   &locale_path, &locale_path_len) != 0)
      return NULL;

  if (__argz_add_sep (&locale_path, &locale_path_len, LOCALE_PATH, ':') != 0)
    return NULL;

  if (category == LC_ALL)
    {
      /* The user wants to set all categories.  The desired locales
	 for the individual categories can be selected by using a
	 composite locale name.  This is a semi-colon separated list
	 of entries of the form `CATEGORY=VALUE'.  */
      const char *newnames[LC_ALL];
      struct locale_data *newdata[LC_ALL];

      /* Set all name pointers to the argument name.  */
      for (category = 0; category < LC_ALL; ++category)
	newnames[category] = (char *) locale;

      if (strchr (locale, ';') != NULL)
	{
	  /* This is a composite name.  Make a copy and split it up.  */
	  char *np = strdupa (locale);
	  char *cp;
	  int cnt;

	  while ((cp = strchr (np, '=')) != NULL)
	    {
	      for (cnt = 0; cnt < LC_ALL; ++cnt)
		if ((size_t) (cp - np) == _nl_category_name_sizes[cnt]
		    && memcmp (np, _nl_category_names[cnt], cp - np) == 0)
		  break;

	      if (cnt == LC_ALL)
		/* Bogus category name.  */
		ERROR_RETURN;

	      /* Found the category this clause sets.  */
	      newnames[cnt] = ++cp;
	      cp = strchr (cp, ';');
	      if (cp != NULL)
		{
		  /* Examine the next clause.  */
		  *cp = '\0';
		  np = cp + 1;
		}
	      else
		/* This was the last clause.  We are done.  */
		break;
	    }

	  for (cnt = 0; cnt < LC_ALL; ++cnt)
	    if (newnames[cnt] == locale)
	      /* The composite name did not specify all categories.  */
	      ERROR_RETURN;
	}

      /* Protect global data.  */
      __libc_lock_lock (__libc_setlocale_lock);

      /* Load the new data for each category.  */
      while (category-- > 0)
	{
	  newdata[category] = _nl_find_locale (locale_path, locale_path_len,
					       category,
					       &newnames[category]);

	  if (newdata[category] == NULL)
	    break;

	  /* We must not simply free a global locale since we have no
	     control over the usage.  So we mark it as un-deletable.  */
	  if (newdata[category]->usage_count != MAX_USAGE_COUNT)
	    newdata[category]->usage_count = MAX_USAGE_COUNT;
	}

      /* Create new composite name.  */
      if (category >= 0
	  || (composite = new_composite_name (LC_ALL, newnames)) == NULL)
	/* Loading this part of the locale failed.  Abort the
	   composite load.  */
	composite = NULL;
      else
	{
	  /* Now we have loaded all the new data.  Put it in place.  */
	  for (category = 0; category < LC_ALL; ++category)
	    {
	      setdata (category, newdata[category]);
	      setname (category, newnames[category]);
	    }
	  setname (LC_ALL, composite);
	}

      /* Critical section left.  */
      __libc_lock_unlock (__libc_setlocale_lock);

      /* Free the resources (the locale path variable.  */
      free (locale_path);

      return composite;
    }
  else
    {
      struct locale_data *newdata = NULL;
      const char *newname = locale;

      /* Protect global data.  */
      __libc_lock_lock (__libc_setlocale_lock);

      if (_nl_current[category] != NULL)
	{
	  /* Only actually load the data if anything will use it.  */
	  newdata = _nl_find_locale (locale_path, locale_path_len, category,
				     &newname);
	  if (newdata == NULL)
	    goto abort_single;

	  /* We must not simply free a global locale since we have no
	     control over the usage.  So we mark it as un-deletable.  */
	  if (newdata->usage_count != MAX_USAGE_COUNT)
	    newdata->usage_count = MAX_USAGE_COUNT;
	}

      /* Create new composite name.  */
      composite = new_composite_name (category, &newname);
      if (composite == NULL)
	{
	  /* Say that we don't have any data loaded.  */
	abort_single:
	  newname = NULL;
	}
      else
	{
	  if (_nl_current[category] != NULL)
	    setdata (category, newdata);

	  setname (category, newname);
	  setname (LC_ALL, composite);
	}

      /* Critical section left.  */
      __libc_lock_unlock (__libc_setlocale_lock);

      /* Free the resources (the locale path variable.  */
      free (locale_path);

      return (char *) newname;
    }
}