/* Handle configuration data.

Copyright (C) 1997-2018 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, see

<http://www.gnu.org/licenses/>. */

#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 <libc-lock.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 = { NULL, 0 };

/* 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, BtowcFct, \

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, BtowcFct, \

MinF, MaxF, MinT, MaxT)

#define BUILTIN_ALIAS(From, To) From "\0" To "\0"

#include "gconv_builtin.h"

#undef BUILTIN_TRANSFORMATION

#undef BUILTIN_ALIAS

};

#include <libio/libioP.h>

#define __getdelim(line, len, c, fp) _IO_getdelim (line, len, c, fp)

/* Value of the GCONV_PATH environment variable. */

const char *__gconv_path_envvar;

/* Test whether there is already a matching module known. */

static int

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;

}

/* The actual code to add aliases. */

static void

add_alias2 (const char *from, const char *to, const char *wp, void *modules)

{

/* Test whether this alias conflicts with any available module. */

if (detect_conflict (from))

/* It does conflict, don't add the alias. */

return;

struct gconv_alias *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);

}

}

/* Add new alias. */

static 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. */

char *from, *to, *wp;

while (__isspace_l (*rp, _nl_C_locobj_ptr))

++rp;

from = wp = rp;

while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))

*wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);

if (*rp == '\0')

/* There is no `to' string on the line. Ignore it. */

return;

*wp++ = '\0';

to = ++rp;

while (__isspace_l (*rp, _nl_C_locobj_ptr))

++rp;

while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))

*wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);

if (to == wp)

/* No `to' string, ignore the line. */

return;

*wp++ = '\0';

add_alias2 (from, to, wp, modules);

}

/* Insert a data structure for a new module in the search tree. */

static void

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

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;

while (__isspace_l (*rp, _nl_C_locobj_ptr))

++rp;

from = rp;

while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))

{

*rp = __toupper_l (*rp, _nl_C_locobj_ptr);

++rp;

}

if (*rp == '\0')

return;

*rp++ = '\0';

to = wp = rp;

while (__isspace_l (*rp, _nl_C_locobj_ptr))

++rp;

while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))

*wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);

if (*rp == '\0')

return;

*wp++ = '\0';

do

++rp;

while (__isspace_l (*rp, _nl_C_locobj_ptr));

module = wp;

while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))

*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')

/* 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. */

fake_alias.fromname = strndupa (from, to - from);

if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare) != NULL)

/* 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 = __mempcpy (tmp, from, to - from);

new_module->to_string = tmp;

tmp = __mempcpy (tmp, to, module - to);

new_module->cost_hi = cost_hi;

new_module->cost_lo = modcounter;

new_module->module_name = tmp;

if (dir_len != 0)

tmp = __mempcpy (tmp, directory, dir_len);

tmp = __mempcpy (tmp, module, 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);

}

}

/* Read the next configuration file. */

static void

read_conf_file (const char *filename, const char *directory, size_t dir_len,

void **modules, size_t *nmodules)

{

/* Note the file is opened with cancellation in the I/O functions

disabled. */

FILE *fp = fopen (filename, "rce");

char *line = NULL;

size_t line_len = 0;

static int modcounter;

/* Don't complain if a file is not present or readable, simply silently

ignore it. */

if (fp == NULL)

return;

/* No threads reading from this stream. */

__fsetlocking (fp, FSETLOCKING_BYCALLER);

/* Process the known entries of the file. Comments start with `#' and

end with the end of the line. Empty lines are ignored. */

while (!__feof_unlocked (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_l (*rp, _nl_C_locobj_ptr))

++rp;

/* If this is an empty line go on with the next one. */

if (rp == endp)

continue;

word = rp;

while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))

++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);

}

/* Determine the directories we are looking for data in. */

void

__gconv_get_path (void)

{

struct path_elem *result;

__libc_lock_define_initialized (static, lock);

__libc_lock_lock (lock);

/* 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)

{

/* No user-defined path. Make a modifiable copy of the

default path. */

gconv_path = strdupa (default_gconv_path);

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);

gconv_path_len = user_len + 1 + sizeof (default_gconv_path);

gconv_path = alloca (gconv_path_len);

__mempcpy (__mempcpy (__mempcpy (gconv_path, __gconv_path_envvar,

user_len),

":", 1),

default_gconv_path, sizeof (default_gconv_path));

cwd = __getcwd (NULL, 0);

cwdlen = __glibc_unlikely (cwd == NULL) ? 0 : 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 = __mempcpy (strspace, cwd, cwdlen);

*strspace++ = '/';

}

strspace = __stpcpy (strspace, elem);

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;

free (cwd);

}

__libc_lock_unlock (lock);

}

/* Read all configuration files found in the user-specified and the default

path. */

void

attribute_hidden

__gconv_read_conf (void)

{

void *modules = NULL;

size_t nmodules = 0;

int save_errno = errno;

size_t cnt;

/* 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)

{

const char *elem = __gconv_path_elem[cnt].name;

size_t elem_len = __gconv_path_elem[cnt].len;

char *filename;

/* 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));

__mempcpy (__mempcpy (filename, elem, elem_len),

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. */

const char *cp = builtin_aliases;

do

{

const char *from = cp;

const char *to = __rawmemchr (from, '\0') + 1;

cp = __rawmemchr (to, '\0') + 1;

add_alias2 (from, to, cp, modules);

}

while (*cp != '\0');

/* Restore the error number. */

__set_errno (save_errno);

}

/* Free all resources if necessary. */

libc_freeres_fn (free_mem)

{

if (__gconv_path_elem != NULL && __gconv_path_elem != &empty_path_elem)

free ((void *) __gconv_path_elem);

}