gconv_conf.c

Newlib 嵌入式 C库 标准实现代码

/* Handle configuration data.
   Copyright (C) 1997,98,99,2000,2001 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <[e-mail]>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

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

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <search.h>
#include <stddef.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/param.h>

#include <dirent.h>
#include <gconv_int.h>

/* This is the default path where we look for module lists.  */
static const char default_gconv_path[] = GCONV_PATH;

/* The path elements, as determined by the __gconv_get_path function.
   All path elements end in a slash.  */
struct path_elem *__gconv_path_elem;
/* Maximum length of a single path element in __gconv_path_elem.  */
size_t __gconv_max_path_elem_len;

/* We use the following struct if we couldn't allocate memory.  */
static const struct path_elem empty_path_elem;

/* Name of the file containing the module information in the directories
   along the path.  */
static const char gconv_conf_filename[] = "gconv-modules";

/* Filename extension for the modules.  */
#ifndef MODULE_EXT
# define MODULE_EXT ".so"
#endif
static const char gconv_module_ext[] = MODULE_EXT;

/* We have a few builtin transformations.  */
static struct gconv_module builtin_modules[] =
{
#define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, MinF, MaxF, \
			       MinT, MaxT) \
  {									      \
    from_string: From,							      \
    to_string: To,							      \
    cost_hi: Cost,							      \
    cost_lo: INT_MAX,							      \
    module_name: Name							      \
  },
#define BUILTIN_ALIAS(From, To)

#include "gconv_builtin.h"
};

#undef BUILTIN_TRANSFORMATION
#undef BUILTIN_ALIAS

static const char *builtin_aliases[] =
{
#define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, MinF, MaxF, \
			       MinT, MaxT)
#define BUILTIN_ALIAS(From, To) From " " To,

#include "gconv_builtin.h"
};

#ifdef USE_IN_LIBIO
# include <libio/libioP.h>
# define __getdelim(line, len, c, fp) _IO_getdelim (line, len, c, fp)
#endif


/* Value of the GCONV_PATH environment variable.  */
const char *__gconv_path_envvar;


/* Test whether there is already a matching module known.  */
static int
internal_function
detect_conflict (const char *alias)
{
  struct gconv_module *node = __gconv_modules_db;

  while (node != NULL)
    {
      int cmpres = strcmp (alias, node->from_string);

      if (cmpres == 0)
	/* We have a conflict.  */
	return 1;
      else if (cmpres < 0)
	node = node->left;
      else
	node = node->right;
    }

  return node != NULL;
}


/* Add new alias.  */
static inline void
add_alias (char *rp, void *modules)
{
  /* We now expect two more string.  The strings are normalized
     (converted to UPPER case) and strored in the alias database.  */
  struct gconv_alias *new_alias;
  char *from, *to, *wp;
  char old_locale[20], *old_locale_p;

  /* Set locale to default C locale. */
  old_locale_p = setlocale(LC_ALL, "C");
  strncpy(old_locale, old_locale_p, 20);

  while (isspace (*rp))
    ++rp;
  from = wp = rp;
  while (*rp != '\0' && !isspace (*rp))
    *wp++ = toupper (*rp++);
  if (*rp == '\0')
    {
      setlocale(LC_ALL, old_locale);
      /* There is no `to' string on the line.  Ignore it.  */
      return;
    }
  *wp++ = '\0';
  to = ++rp;
  while (isspace (*rp))
    ++rp;
  while (*rp != '\0' && !isspace (*rp))
    *wp++ = toupper (*rp++);
  if (to == wp)
    {
      setlocale(LC_ALL, old_locale);
      /* No `to' string, ignore the line.  */
      return;
    }
  *wp++ = '\0';

  /* Test whether this alias conflicts with any available module.  */
  if (detect_conflict (from))
    {
      setlocale(LC_ALL, old_locale);
      /* It does conflict, don't add the alias.  */
      return;
    }

  new_alias = (struct gconv_alias *) malloc (sizeof (struct gconv_alias) + (wp - from));
  if (new_alias != NULL)
    {
      void **inserted;

      new_alias->fromname = memcpy ((char *) new_alias
				    + sizeof (struct gconv_alias),
				    from, wp - from);
      new_alias->toname = new_alias->fromname + (to - from);

      inserted = (void **) tsearch (new_alias, &__gconv_alias_db,
				      __gconv_alias_compare);
      if (inserted == NULL || *inserted != new_alias)
	/* Something went wrong, free this entry.  */
	free (new_alias);
    }
  setlocale(LC_ALL, old_locale);
}


/* Insert a data structure for a new module in the search tree.  */
static inline void
internal_function
insert_module (struct gconv_module *newp, int tobefreed)
{
  struct gconv_module **rootp = &__gconv_modules_db;

  while (*rootp != NULL)
    {
      struct gconv_module *root = *rootp;
      int cmpres;

      cmpres = strcmp (newp->from_string, root->from_string);
      if (cmpres == 0)
	{
	  /* Both strings are identical.  Insert the string at the
	     end of the `same' list if it is not already there.  */
	  while (strcmp (newp->from_string, root->from_string) != 0
		 || strcmp (newp->to_string, root->to_string) != 0)
	    {
	      rootp = &root->same;
	      root = *rootp;
	      if (root == NULL)
		break;
	    }

	  if (root != NULL)
	    {
	      /* This is a no new conversion.  But maybe the cost is
		 better.  */
	      if (newp->cost_hi < root->cost_hi
		  || (newp->cost_hi == root->cost_hi
		      && newp->cost_lo < root->cost_lo))
		{
		  newp->left = root->left;
		  newp->right = root->right;
		  newp->same = root->same;
		  *rootp = newp;

		  free (root);
		}
	      else if (tobefreed)
		free (newp);
	      return;
	    }

	  break;
	}
      else if (cmpres < 0)
	rootp = &root->left;
      else
	rootp = &root->right;
    }

  /* Plug in the new node here.  */
  *rootp = newp;
}


/* Add new module.  */
static void
internal_function
add_module (char *rp, const char *directory, size_t dir_len, void **modules,
	    size_t *nmodules, int modcounter)
{
  /* We expect now
     1. `from' name
     2. `to' name
     3. filename of the module
     4. an optional cost value
  */
  struct gconv_alias fake_alias;
  struct gconv_module *new_module;
  char *from, *to, *module, *wp;
  int need_ext;
  int cost_hi;
  char old_locale[20], *old_locale_p;
  char *old;
  size_t len;
  char *new;

  /* Set locale to default C locale. */
  old_locale_p = setlocale(LC_ALL, "C");
  strncpy(old_locale, old_locale_p, 20);

  while (isspace (*rp))
    ++rp;
  from = rp;
  while (*rp != '\0' && !isspace (*rp))
    {
      *rp = toupper (*rp);
      ++rp;
    }
  if (*rp == '\0')
    {
      setlocale(LC_ALL, old_locale);
      return;
    }
  *rp++ = '\0';
  to = wp = rp;
  while (isspace (*rp))
    {
      setlocale(LC_ALL, old_locale);
      ++rp;
    }
  while (*rp != '\0' && !isspace (*rp))
    *wp++ = toupper (*rp++);
  if (*rp == '\0')
    {
      setlocale(LC_ALL, old_locale);
      return;
    }
  *wp++ = '\0';
  do
    ++rp;
  while (isspace (*rp));
  module = wp;
  while (*rp != '\0' && !isspace (*rp))
    *wp++ = *rp++;
  if (*rp == '\0')
    {
      /* There is no cost, use one by default.  */
      *wp++ = '\0';
      cost_hi = 1;
    }
  else
    {
      /* There might be a cost value.  */
      char *endp;

      *wp++ = '\0';
      cost_hi = strtol (rp, &endp, 10);
      if (rp == endp || cost_hi < 1)
	/* No useful information.  */
	cost_hi = 1;
    }

  if (module[0] == '\0')
    {
      setlocale(LC_ALL, old_locale);
      /* No module name given.  */
      return;
    }
  if (module[0] == '/')
    dir_len = 0;

  /* See whether we must add the ending.  */
  need_ext = 0;
  if (wp - module < (ptrdiff_t) sizeof (gconv_module_ext)
      || memcmp (wp - sizeof (gconv_module_ext), gconv_module_ext,
		 sizeof (gconv_module_ext)) != 0)
    /* We must add the module extension.  */