source: trunk/libs/newlib/src/newlib/libc/sys/linux/iconv/gconv_conf.c

/* 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 <drepper@cygnus.com>, 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.  */
    need_ext = sizeof (gconv_module_ext) - 1;

  /* See whether we have already an alias with this name defined.  */
  old = from;
  len = strnlen (old, to - from);
  new = (char *) alloca (len + 1);
  new[len] = '\0';
  fake_alias.fromname = (char *) memcpy (new, old, len);

  if (tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare) != NULL)
    {
      setlocale(LC_ALL, old_locale);
      /* This module duplicates an alias.  */
      return;
    }

  new_module = (struct gconv_module *) calloc (1,
                                               sizeof (struct gconv_module)
                                               + (wp - from)
                                               + dir_len + need_ext);
  if (new_module != NULL)
    {
      char *tmp;

      new_module->from_string = tmp = (char *) (new_module + 1);
      tmp = memcpy (tmp, from, to - from);
      tmp += (to - from);

      new_module->to_string = tmp;
      tmp = memcpy (tmp, to, module - to);
      tmp += (module - to);

      new_module->cost_hi = cost_hi;
      new_module->cost_lo = modcounter;

      new_module->module_name = tmp;

      if (dir_len != 0)
        {
          tmp = memcpy (tmp, directory, dir_len);
          tmp += dir_len;
        }

      tmp = memcpy (tmp, module, wp - module);
      tmp += (wp - module);

      if (need_ext)
        memcpy (tmp - 1, gconv_module_ext, sizeof (gconv_module_ext));

      /* Now insert the new module data structure in our search tree.  */
      insert_module (new_module, 1);
    }
  setlocale(LC_ALL, old_locale);
}


/* Read the next configuration file.  */
static void
internal_function
read_conf_file (const char *filename, const char *directory, size_t dir_len,
                void **modules, size_t *nmodules)
{
  FILE *fp = fopen (filename, "r");
  char *line = NULL;
  size_t line_len = 0;
  static int modcounter;
  char old_locale[20], *old_locale_p;

  /* Don't complain if a file is not present or readable, simply silently
     ignore it.  */
  if (fp == NULL)
    return;

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

  /* Process the known entries of the file.  Comments start with `#' and
     end with the end of the line.  Empty lines are ignored.  */
  while (!feof (fp))
    {
      char *rp, *endp, *word;
      ssize_t n = __getdelim (&line, &line_len, '\n', fp);
      if (n < 0)
        /* An error occurred.  */
        break;

      rp = line;
      /* Terminate the line (excluding comments or newline) by an NUL byte
         to simplify the following code.  */
      endp = strchr (rp, '#');
      if (endp != NULL)
        *endp = '\0';
      else
        if (rp[n - 1] == '\n')
          rp[n - 1] = '\0';

      while (isspace (*rp))
        ++rp;

      /* If this is an empty line go on with the next one.  */
      if (rp == endp)
        continue;

      word = rp;
      while (*rp != '\0' && !isspace (*rp))
        ++rp;

      if (rp - word == sizeof ("alias") - 1
          && memcmp (word, "alias", sizeof ("alias") - 1) == 0)
        add_alias (rp, *modules);
      else if (rp - word == sizeof ("module") - 1
               && memcmp (word, "module", sizeof ("module") - 1) == 0)
        add_module (rp, directory, dir_len, modules, nmodules, modcounter++);
      /* else */
        /* Otherwise ignore the line.  */
    }

  free (line);

  fclose (fp);

  setlocale(LC_ALL, old_locale);
}


/* Determine the directories we are looking for data in.  */
void
__gconv_get_path (void)
{
  struct path_elem *result;
  __LOCK_INIT(static, path_lock);

#ifdef HAVE_DD_LOCK
  __lock_acquire(path_lock);
#endif

  /* Make sure there wasn't a second thread doing it already.  */
  result = (struct path_elem *) __gconv_path_elem;
  if (result == NULL)
    {
      /* Determine the complete path first.  */
      char *gconv_path;
      size_t gconv_path_len;
      char *elem;
      char *oldp;
      char *cp;
      int nelems;
      char *cwd;
      size_t cwdlen;

      if (__gconv_path_envvar == NULL)
        {
          char * old = default_gconv_path;
          size_t len = strlen (old) + 1;
          char *new = (char *) alloca (len);

          /* No user-defined path.  Make a modifiable copy of the
             default path.  */
          gconv_path = (char *) memcpy (new, old, len);
          gconv_path_len = sizeof (default_gconv_path);
          cwd = NULL;
          cwdlen = 0;
        }
      else
        {
          /* Append the default path to the user-defined path.  */
          size_t user_len = strlen (__gconv_path_envvar);
          char *tmp;

          gconv_path_len = user_len + 1 + sizeof (default_gconv_path);
          gconv_path = alloca (gconv_path_len);
          tmp = memcpy (gconv_path, __gconv_path_envvar,
                        user_len);
          tmp += user_len;
          memcpy (tmp, ":", 1);
          tmp += 1;
          memcpy (tmp,
                  default_gconv_path, sizeof (default_gconv_path));

          cwd = getcwd (NULL, 0);
          cwdlen = strlen (cwd);
        }
      assert (default_gconv_path[0] == '/');

      /* In a first pass we calculate the number of elements.  */
      oldp = NULL;
      cp = strchr (gconv_path, ':');
      nelems = 1;
      while (cp != NULL)
        {
          if (cp != oldp + 1)
            ++nelems;
          oldp = cp;
          cp =  strchr (cp + 1, ':');
        }

      /* Allocate the memory for the result.  */
      result = (struct path_elem *) malloc ((nelems + 1)
                                            * sizeof (struct path_elem)
                                            + gconv_path_len + nelems
                                            + (nelems - 1) * (cwdlen + 1));
      if (result != NULL)
        {
          char *strspace = (char *) &result[nelems + 1];
          int n = 0;

          /* Separate the individual parts.  */
          __gconv_max_path_elem_len = 0;
          elem = strtok_r (gconv_path, ":", &gconv_path);
          assert (elem != NULL);
          do
            {
              result[n].name = strspace;
              if (elem[0] != '/')
                {
                  assert (cwd != NULL);
                  strspace = memcpy (strspace, cwd, cwdlen);
                  strspace += cwdlen;
                  *strspace++ = '/';
                }
              strspace = strcpy (strspace, elem);
              while(*strspace != '\0') strspace++;

              if (strspace[-1] != '/')
                *strspace++ = '/';

              result[n].len = strspace - result[n].name;
              if (result[n].len > __gconv_max_path_elem_len)
                __gconv_max_path_elem_len = result[n].len;

              *strspace++ = '\0';
              ++n;
            }
          while ((elem = strtok_r (NULL, ":", &gconv_path)) != NULL);

          result[n].name = NULL;
          result[n].len = 0;
        }

      __gconv_path_elem = result ?: (struct path_elem *) &empty_path_elem;

      if (cwd != NULL)
        free (cwd);
    }

#ifdef HAVE_DD_LOCK
  __lock_release(path_lock);
#endif
}


/* Read all configuration files found in the user-specified and the default
   path.  */
void
__gconv_read_conf (void)
{
  void *modules = NULL;
  size_t nmodules = 0;
  int save_errno = errno;
  size_t cnt;
  char *filename;
  char *tmp;
  const char *elem;
  size_t elem_len;

  /* First see whether we should use the cache.  */
  if (__gconv_load_cache () == 0)
    {
      /* Yes, we are done.  */
      __set_errno (save_errno);
      return;
    }

#ifndef STATIC_GCONV
  /* Find out where we have to look.  */
  if (__gconv_path_elem == NULL)
    __gconv_get_path ();

  for (cnt = 0; __gconv_path_elem[cnt].name != NULL; ++cnt)
    {
      elem = __gconv_path_elem[cnt].name;
      elem_len = __gconv_path_elem[cnt].len;

      /* No slash needs to be inserted between elem and gconv_conf_filename;
         elem already ends in a slash.  */
      filename = alloca (elem_len + sizeof (gconv_conf_filename));
      tmp = memcpy (filename, elem, elem_len);
      tmp += elem_len;
      memcpy (tmp, gconv_conf_filename, sizeof (gconv_conf_filename));

      /* Read the next configuration file.  */
      read_conf_file (filename, elem, elem_len, &modules, &nmodules);
    }
#endif

  /* Add the internal modules.  */
  for (cnt = 0; cnt < sizeof (builtin_modules) / sizeof (builtin_modules[0]);
       ++cnt)
    {
      struct gconv_alias fake_alias;

      fake_alias.fromname = (char *) builtin_modules[cnt].from_string;

      if (tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare)
          != NULL)
        /* It'll conflict so don't add it.  */
        continue;

      insert_module (&builtin_modules[cnt], 0);
    }

  /* Add aliases for builtin conversions.  */
  cnt = sizeof (builtin_aliases) / sizeof (builtin_aliases[0]);
  while (cnt > 0)
    {
      char * old = builtin_aliases[--cnt];
      size_t len = strlen (old) + 1;
      char *new = (char *) alloca (len);
      char *copy = (char *) memcpy (new, old, len);

      add_alias (copy, modules);
    }

  /* Restore the error number.  */
  __set_errno (save_errno);
}



/* Free all resources if necessary.  */
static void __attribute__ ((unused))
free_mem (void)
{
  if (__gconv_path_elem != NULL && __gconv_path_elem != &empty_path_elem)
    free ((void *) __gconv_path_elem);
}

text_set_element (__libc_subfreeres, free_mem);