/*      $NetBSD: citrus_mapper.c,v 1.10 2012/06/08 07:49:42 martin Exp $        */

/*-
* Copyright (c)2003 Citrus Project,
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: citrus_mapper.c,v 1.10 2012/06/08 07:49:42 martin Exp $");
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include "reentrant.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/queue.h>

#include "citrus_namespace.h"
#include "citrus_types.h"
#include "citrus_region.h"
#include "citrus_memstream.h"
#include "citrus_bcs.h"
#include "citrus_mmap.h"
#include "citrus_module.h"
#include "citrus_hash.h"
#include "citrus_mapper.h"

#define _CITRUS_MAPPER_DIR      "mapper.dir"

#define CM_HASH_SIZE 101
#define REFCOUNT_PERSISTENT     -1

#ifdef _REENTRANT
static rwlock_t lock = RWLOCK_INITIALIZER;
#endif

struct _citrus_mapper_area {
       _CITRUS_HASH_HEAD(, _citrus_mapper, CM_HASH_SIZE)       ma_cache;
       char                                                    *ma_dir;
};

/*
* _citrus_mapper_create_area:
*      create mapper area
*/

int
_citrus_mapper_create_area(
       struct _citrus_mapper_area *__restrict *__restrict rma,
       const char *__restrict area)
{
       struct stat st;
       int ret;
       char path[PATH_MAX];
       struct _citrus_mapper_area *ma;

       rwlock_wrlock(&lock);

       if (*rma != NULL) {
               ret = 0;
               goto quit;
       }

       snprintf(path, (size_t)PATH_MAX, "%s/%s", area, _CITRUS_MAPPER_DIR);

       ret = stat(path, &st);
       if (ret)
               goto quit;

       ma = malloc(sizeof(*ma));
       if (ma == NULL) {
               ret = errno;
               goto quit;
       }
       ma->ma_dir = strdup(area);
       if (ma->ma_dir == NULL) {
               free(ma);
               ret = errno;
               goto quit;
       }
       _CITRUS_HASH_INIT(&ma->ma_cache, CM_HASH_SIZE);

       *rma = ma;
       ret = 0;
quit:
       rwlock_unlock(&lock);

       return ret;
}


/*
* lookup_mapper_entry:
*      lookup mapper.dir entry in the specified directory.
*
* line format of iconv.dir file:
*      mapper  module  arg
* mapper : mapper name.
* module : mapper module name.
* arg    : argument for the module (generally, description file name)
*/

static int
lookup_mapper_entry(const char *dir, const char *mapname,
                   void *linebuf, size_t linebufsize,
                   const char **module, const char **variable)
{
       struct _region r;
       struct _memstream ms;
       int ret;
       const char *cp, *cq;
       char *p;
       size_t len;
       char path[PATH_MAX];

       /* create mapper.dir path */
       snprintf(path, (size_t)PATH_MAX, "%s/%s", dir, _CITRUS_MAPPER_DIR);

       /* open read stream */
       ret = _map_file(&r, path);
       if (ret)
               return ret;

       _memstream_bind(&ms, &r);

       /* search the line matching to the map name */
       cp = _memstream_matchline(&ms, mapname, &len, 0);
       if (!cp) {
               ret = ENOENT;
               goto quit;
       }
       if (!len || len>linebufsize-1) {
               ret = EINVAL;
               goto quit;
       }

       p = linebuf;
       /* get module name */
       *module = p;
       cq = _bcs_skip_nonws_len(cp, &len);
       strlcpy(p, cp, (size_t)(cq-cp+1));
       p += cq-cp+1;

       /* get variable */
       *variable = p;
       cp = _bcs_skip_ws_len(cq, &len);
       strlcpy(p, cp, len+1);

       ret = 0;

quit:
       _unmap_file(&r);
       return ret;
}

/*
* mapper_close:
*      simply close a mapper. (without handling hash)
*/
static void
mapper_close(struct _citrus_mapper *cm)
{
       if (cm->cm_module) {
               if (cm->cm_ops) {
                       if (cm->cm_closure)
                               (*cm->cm_ops->mo_uninit)(cm);
                       free(cm->cm_ops);
               }
               _citrus_unload_module(cm->cm_module);
       }
       free(cm->cm_traits);
       free(cm);
}

/*
* mapper_open:
*      simply open a mapper. (without handling hash)
*/
static int
mapper_open(struct _citrus_mapper_area *__restrict ma,
           struct _citrus_mapper * __restrict * __restrict rcm,
           const char * __restrict module,
           const char * __restrict variable)
{
       int ret;
       struct _citrus_mapper *cm;
       _citrus_mapper_getops_t getops;

       /* initialize mapper handle */
       cm = malloc(sizeof(*cm));
       if (!cm)
               return errno;

       cm->cm_module = NULL;
       cm->cm_ops = NULL;
       cm->cm_closure = NULL;
       cm->cm_traits = NULL;
       cm->cm_refcount = 0;
       cm->cm_key = NULL;

       /* load module */
       ret = _citrus_load_module(&cm->cm_module, module);
       if (ret)
               goto err;

       /* get operators */
       getops = (_citrus_mapper_getops_t)
           _citrus_find_getops(cm->cm_module, module, "mapper");
       if (!getops) {
               ret = EOPNOTSUPP;
               goto err;
       }
       cm->cm_ops = malloc(sizeof(*cm->cm_ops));
       if (!cm->cm_ops) {
               ret = errno;
               goto err;
       }
       ret = (*getops)(cm->cm_ops, sizeof(*cm->cm_ops),
                       _CITRUS_MAPPER_ABI_VERSION);
       if (ret)
               goto err;

       if (!cm->cm_ops->mo_init ||
           !cm->cm_ops->mo_uninit ||
           !cm->cm_ops->mo_convert ||
           !cm->cm_ops->mo_init_state) {
               ret = EINVAL;
               goto err;
       }

       /* allocate traits structure */
       cm->cm_traits = malloc(sizeof(*cm->cm_traits));
       if (cm->cm_traits == NULL) {
               ret = errno;
               goto err;
       }
       /* initialize the mapper */
       ret = (*cm->cm_ops->mo_init)(ma, cm, ma->ma_dir,
                                    (const void *)variable,
                                    strlen(variable)+1,
                                    cm->cm_traits, sizeof(*cm->cm_traits));
       if (ret)
               goto err;

       *rcm = cm;

       return 0;

err:
       mapper_close(cm);
       return ret;
}

/*
* _citrus_mapper_open_direct:
*      open a mapper.
*/
int
_citrus_mapper_open_direct(struct _citrus_mapper_area *__restrict ma,
                          struct _citrus_mapper * __restrict * __restrict rcm,
                          const char * __restrict module,
                          const char * __restrict variable)
{
       return mapper_open(ma, rcm, module, variable);
}

/*
* hash_func
*/
static __inline int
hash_func(const char *key)
{
       return _string_hash_func(key, CM_HASH_SIZE);
}

/*
* match_func
*/
static __inline int
match_func(struct _citrus_mapper *cm, const char *key)
{
       return strcmp(cm->cm_key, key);
}

/*
* _citrus_mapper_open:
*      open a mapper with looking up "mapper.dir".
*/
int
_citrus_mapper_open(struct _citrus_mapper_area *__restrict ma,
                   struct _citrus_mapper * __restrict * __restrict rcm,
                   const char * __restrict mapname)
{
       int ret;
       char linebuf[PATH_MAX];
       const char *module, *variable = NULL;
       struct _citrus_mapper *cm;
       int hashval;

       rwlock_wrlock(&lock);

       /* search in the cache */
       hashval = hash_func(mapname);
       _CITRUS_HASH_SEARCH(&ma->ma_cache, cm, cm_entry, match_func, mapname,
                           hashval);
       if (cm) {
               /* found */
               cm->cm_refcount++;
               *rcm = cm;
               ret = 0;
               goto quit;
       }

       /* search mapper entry */
       ret = lookup_mapper_entry(ma->ma_dir, mapname, linebuf,
           (size_t)PATH_MAX, &module, &variable);
       if (ret)
               goto quit;

       /* open mapper */
       ret = mapper_open(ma, &cm, module, variable);
       if (ret)
               goto quit;
       cm->cm_key = strdup(mapname);
       if (cm->cm_key == NULL) {
               ret = errno;
               rwlock_unlock(&lock);
               _mapper_close(cm);
               return ret;
       }

       /* insert to the cache */
       cm->cm_refcount = 1;
       _CITRUS_HASH_INSERT(&ma->ma_cache, cm, cm_entry, hashval);

       *rcm = cm;
       ret = 0;
quit:
       rwlock_unlock(&lock);
       return ret;
}

/*
* _citrus_mapper_close:
*      close the specified mapper.
*/
void
_citrus_mapper_close(struct _citrus_mapper *cm)
{
       if (cm) {
               rwlock_wrlock(&lock);
               if (cm->cm_refcount == REFCOUNT_PERSISTENT)
                       goto quit;
               if (cm->cm_refcount > 0) {
                       if (--cm->cm_refcount > 0)
                               goto quit;
                       _CITRUS_HASH_REMOVE(cm, cm_entry);
                       free(cm->cm_key);
               }
               rwlock_unlock(&lock);
               mapper_close(cm);
               return;
quit:
               rwlock_unlock(&lock);
       }
}

/*
* _citrus_mapper_set_persistent:
*      set persistent count.
*/
void
_citrus_mapper_set_persistent(struct _citrus_mapper * __restrict cm)
{
       rwlock_wrlock(&lock);
       cm->cm_refcount = REFCOUNT_PERSISTENT;
       rwlock_unlock(&lock);
}

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