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glibc/iconv/gconv_cache.c

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/* Cache handling for iconv modules.
Copyright (C) 2001, 2002, 2003, 2005 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 2001.
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 <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <gconv_int.h>
#include <iconvconfig.h>
#include <not-cancel.h>
#include "../intl/hash-string.h"
static void *gconv_cache;
static size_t cache_size;
static int cache_malloced;
void *
__gconv_get_cache (void)
{
return gconv_cache;
}
int
internal_function
__gconv_load_cache (void)
{
int fd;
struct stat64 st;
struct gconvcache_header *header;
/* We cannot use the cache if the GCONV_PATH environment variable is
set. */
__gconv_path_envvar = getenv ("GCONV_PATH");
if (__gconv_path_envvar != NULL)
return -1;
/* See whether the cache file exists. */
fd = open_not_cancel (GCONV_MODULES_CACHE, O_RDONLY, 0);
if (__builtin_expect (fd, 0) == -1)
/* Not available. */
return -1;
/* Get information about the file. */
if (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) < 0
/* We do not have to start looking at the file if it cannot contain
at least the cache header. */
|| (size_t) st.st_size < sizeof (struct gconvcache_header))
{
close_and_exit:
close_not_cancel_no_status (fd);
return -1;
}
/* Make the file content available. */
cache_size = st.st_size;
#ifdef _POSIX_MAPPED_FILES
gconv_cache = __mmap (NULL, cache_size, PROT_READ, MAP_SHARED, fd, 0);
if (__builtin_expect (gconv_cache == MAP_FAILED, 0))
#endif
{
size_t already_read;
gconv_cache = malloc (cache_size);
if (gconv_cache == NULL)
goto close_and_exit;
already_read = 0;
do
{
ssize_t n = __read (fd, (char *) gconv_cache + already_read,
cache_size - already_read);
if (__builtin_expect (n, 0) == -1)
{
free (gconv_cache);
gconv_cache = NULL;
goto close_and_exit;
}
already_read += n;
}
while (already_read < cache_size);
cache_malloced = 1;
}
/* We don't need the file descriptor anymore. */
close_not_cancel_no_status (fd);
/* Check the consistency. */
header = (struct gconvcache_header *) gconv_cache;
if (__builtin_expect (header->magic, GCONVCACHE_MAGIC) != GCONVCACHE_MAGIC
|| __builtin_expect (header->string_offset >= cache_size, 0)
|| __builtin_expect (header->hash_offset >= cache_size, 0)
|| __builtin_expect (header->hash_size == 0, 0)
|| __builtin_expect ((header->hash_offset
+ header->hash_size * sizeof (struct hash_entry))
> cache_size, 0)
|| __builtin_expect (header->module_offset >= cache_size, 0)
|| __builtin_expect (header->otherconv_offset > cache_size, 0))
{
if (cache_malloced)
{
free (gconv_cache);
cache_malloced = 0;
}
#ifdef _POSIX_MAPPED_FILES
else
__munmap (gconv_cache, cache_size);
#endif
gconv_cache = NULL;
return -1;
}
/* That worked. */
return 0;
}
static int
internal_function
find_module_idx (const char *str, size_t *idxp)
{
unsigned int idx;
unsigned int hval;
unsigned int hval2;
const struct gconvcache_header *header;
const char *strtab;
const struct hash_entry *hashtab;
unsigned int limit;
header = (const struct gconvcache_header *) gconv_cache;
strtab = (char *) gconv_cache + header->string_offset;
hashtab = (struct hash_entry *) ((char *) gconv_cache
+ header->hash_offset);
hval = __hash_string (str);
idx = hval % header->hash_size;
hval2 = 1 + hval % (header->hash_size - 2);
limit = cache_size - header->string_offset;
while (hashtab[idx].string_offset != 0)
if (hashtab[idx].string_offset < limit
&& strcmp (str, strtab + hashtab[idx].string_offset) == 0)
{
*idxp = hashtab[idx].module_idx;
return 0;
}
else
if ((idx += hval2) >= header->hash_size)
idx -= header->hash_size;
/* Nothing found. */
return -1;
}
#ifndef STATIC_GCONV
static int
internal_function
find_module (const char *directory, const char *filename,
struct __gconv_step *result)
{
size_t dirlen = strlen (directory);
size_t fnamelen = strlen (filename) + 1;
char fullname[dirlen + fnamelen];
int status = __GCONV_NOCONV;
memcpy (__mempcpy (fullname, directory, dirlen), filename, fnamelen);
result->__shlib_handle = __gconv_find_shlib (fullname);
if (result->__shlib_handle != NULL)
{
status = __GCONV_OK;
result->__modname = NULL;
result->__fct = result->__shlib_handle->fct;
result->__init_fct = result->__shlib_handle->init_fct;
result->__end_fct = result->__shlib_handle->end_fct;
/* These settings can be overridden by the init function. */
result->__btowc_fct = NULL;
result->__data = NULL;
/* Call the init function. */
if (result->__init_fct != NULL)
{
__gconv_init_fct init_fct = result->__init_fct;
#ifdef PTR_DEMANGLE
PTR_DEMANGLE (init_fct);
#endif
status = DL_CALL_FCT (init_fct, (result));
#ifdef PTR_MANGLE
if (result->__btowc_fct != NULL)
PTR_MANGLE (result->__btowc_fct);
#endif
}
}
return status;
}
#endif
int
internal_function
__gconv_compare_alias_cache (const char *name1, const char *name2, int *result)
{
size_t name1_idx;
size_t name2_idx;
if (gconv_cache == NULL)
return -1;
if (find_module_idx (name1, &name1_idx) != 0
|| find_module_idx (name2, &name2_idx) != 0)
*result = strcmp (name1, name2);
else
*result = (int) (name1_idx - name2_idx);
return 0;
}
int
internal_function
__gconv_lookup_cache (const char *toset, const char *fromset,
struct __gconv_step **handle, size_t *nsteps, int flags)
{
const struct gconvcache_header *header;
const char *strtab;
size_t fromidx;
size_t toidx;
const struct module_entry *modtab;
const struct module_entry *from_module;
const struct module_entry *to_module;
struct __gconv_step *result;
if (gconv_cache == NULL)
/* We have no cache available. */
return __GCONV_NODB;
header = (const struct gconvcache_header *) gconv_cache;
strtab = (char *) gconv_cache + header->string_offset;
modtab = (const struct module_entry *) ((char *) gconv_cache
+ header->module_offset);
if (find_module_idx (fromset, &fromidx) != 0
|| (header->module_offset + (fromidx + 1) * sizeof (struct module_entry)
> cache_size))
return __GCONV_NOCONV;
from_module = &modtab[fromidx];
if (find_module_idx (toset, &toidx) != 0
|| (header->module_offset + (toidx + 1) * sizeof (struct module_entry)
> cache_size))
return __GCONV_NOCONV;
to_module = &modtab[toidx];
/* Avoid copy-only transformations if the user requests. */
if (__builtin_expect (flags & GCONV_AVOID_NOCONV, 0) && fromidx == toidx)
return __GCONV_NOCONV;
/* If there are special conversions available examine them first. */
if (fromidx != 0 && toidx != 0
&& __builtin_expect (from_module->extra_offset, 0) != 0)
{
/* Search through the list to see whether there is a module
matching the destination character set. */
const struct extra_entry *extra;
/* Note the -1. This is due to the offset added in iconvconfig.
See there for more explanations. */
extra = (const struct extra_entry *) ((char *) gconv_cache
+ header->otherconv_offset
+ from_module->extra_offset - 1);
while (extra->module_cnt != 0
&& extra->module[extra->module_cnt - 1].outname_offset != toidx)
extra = (const struct extra_entry *) ((char *) extra
+ sizeof (struct extra_entry)
+ (extra->module_cnt
* sizeof (struct extra_entry_module)));
if (extra->module_cnt != 0)
{
/* Use the extra module. First determine how many steps. */
char *fromname;
int idx;
*nsteps = extra->module_cnt;
*handle = result =
(struct __gconv_step *) malloc (extra->module_cnt
* sizeof (struct __gconv_step));
if (result == NULL)
return __GCONV_NOMEM;
fromname = (char *) strtab + from_module->canonname_offset;
idx = 0;
do
{
result[idx].__from_name = fromname;
fromname = result[idx].__to_name =
(char *) strtab + modtab[extra->module[idx].outname_offset].canonname_offset;
result[idx].__counter = 1;
result[idx].__data = NULL;
#ifndef STATIC_GCONV
if (strtab[extra->module[idx].dir_offset] != '\0')
{
/* Load the module, return handle for it. */
int res;
res = find_module (strtab + extra->module[idx].dir_offset,
strtab + extra->module[idx].name_offset,
&result[idx]);
if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
{
/* Something went wrong. */
free (result);
goto try_internal;
}
}
else
#endif
/* It's a builtin transformation. */
__gconv_get_builtin_trans (strtab
+ extra->module[idx].name_offset,
&result[idx]);
}
while (++idx < extra->module_cnt);
return __GCONV_OK;
}
}
try_internal:
/* See whether we can convert via the INTERNAL charset. */
if ((fromidx != 0 && __builtin_expect (from_module->fromname_offset, 1) == 0)
|| (toidx != 0 && __builtin_expect (to_module->toname_offset, 1) == 0)
|| (fromidx == 0 && toidx == 0))
/* Not possible. Nothing we can do. */
return __GCONV_NOCONV;
/* We will use up to two modules. Always allocate room for two. */
result = (struct __gconv_step *) malloc (2 * sizeof (struct __gconv_step));
if (result == NULL)
return __GCONV_NOMEM;
*handle = result;
*nsteps = 0;
/* Generate data structure for conversion to INTERNAL. */
if (fromidx != 0)
{
result[0].__from_name = (char *) strtab + from_module->canonname_offset;
result[0].__to_name = (char *) "INTERNAL";
result[0].__counter = 1;
result[0].__data = NULL;
#ifndef STATIC_GCONV
if (strtab[from_module->todir_offset] != '\0')
{
/* Load the module, return handle for it. */
int res = find_module (strtab + from_module->todir_offset,
strtab + from_module->toname_offset,
&result[0]);
if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
{
/* Something went wrong. */
free (result);
return res;
}
}
else
#endif
/* It's a builtin transformation. */
__gconv_get_builtin_trans (strtab + from_module->toname_offset,
&result[0]);
++*nsteps;
}
/* Generate data structure for conversion from INTERNAL. */
if (toidx != 0)
{
int idx = *nsteps;
result[idx].__from_name = (char *) "INTERNAL";
result[idx].__to_name = (char *) strtab + to_module->canonname_offset;
result[idx].__counter = 1;
result[idx].__data = NULL;
#ifndef STATIC_GCONV
if (strtab[to_module->fromdir_offset] != '\0')
{
/* Load the module, return handle for it. */
int res = find_module (strtab + to_module->fromdir_offset,
strtab + to_module->fromname_offset,
&result[idx]);
if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
{
/* Something went wrong. */
if (idx != 0)
__gconv_release_step (&result[0]);
free (result);
return res;
}
}
else
#endif
/* It's a builtin transformation. */
__gconv_get_builtin_trans (strtab + to_module->fromname_offset,
&result[idx]);
++*nsteps;
}
return __GCONV_OK;
}
/* Free memory allocated for the transformation record. */
void
internal_function
__gconv_release_cache (struct __gconv_step *steps, size_t nsteps)
{
if (gconv_cache != NULL)
/* The only thing we have to deallocate is the record with the
steps. */
free (steps);
}
/* Free all resources if necessary. */
libc_freeres_fn (free_mem)
{
if (cache_malloced)
free (gconv_cache);
#ifdef _POSIX_MAPPED_FILES
else if (gconv_cache != NULL)
__munmap (gconv_cache, cache_size);
#endif
}
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