/* vi:ai:et:ts=8 sw=2
 */
/*
 * wzdftpd - a modular and cool ftp server
 * Copyright (C) 2002-2008  Pierre Chifflier
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * As a special exemption, Pierre Chifflier
 * and other respective copyright holders give permission to link this program
 * with OpenSSL, and distribute the resulting executable, without including
 * the source code for OpenSSL in the source distribution.
 */

#include "wzd_all.h"

#ifndef WZD_USE_PCH

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>

#include <sys/types.h>

#ifdef WIN32
#include <winsock2.h>
#include <direct.h> /* _getcwd */
#else
#include <unistd.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#endif

#include "wzd_structs.h"

#include "wzd_fs.h"
#include "wzd_group.h"
#include "wzd_libmain.h"
#include "wzd_log.h"
#include "wzd_misc.h"
#include "wzd_user.h"

#include "wzd_debug.h"

#endif /* WZD_USE_PCH */

static gid_t _max_gid = 0;
static wzd_group_t ** _group_array = NULL;

/** \brief Allocate a new empty structure for a group
 */
wzd_group_t * group_allocate(void)
{
  wzd_group_t * group;

  group = wzd_malloc(sizeof(wzd_group_t));

  WZD_ASSERT_RETURN(group != NULL, NULL);
  if (group == NULL) {
    out_log(LEVEL_CRITICAL,"FATAL group_allocate out of memory\n");
    return NULL;
  }

  group_init_struct(group);

  return group;
}

/** \brief Initialize members of struct \a group
 */
void group_init_struct(wzd_group_t * group)
{
  WZD_ASSERT_VOID(group != NULL);
  if (group == NULL) return;

  memset(group,0,sizeof(wzd_group_t));

  group->gid = (gid_t)-1;
  group->groupperms = 0xffffffff;
}

/** \brief Free memory used by a \a group structure
 */
void group_free(wzd_group_t * group)
{
  if (group == NULL) return;

  ip_list_free(group->ip_list);
  wzd_free(group);
}

/** \brief Create a new group, giving default parameters
 * \return The new group, or NULL. If \a err is provided, set it to
 * the error code.
 */
wzd_group_t * group_create(const char * groupname, wzd_context_t * context, wzd_config_t * config, int * err)
{
  wzd_group_t * newgroup;
  const char * homedir;

  WZD_ASSERT_RETURN( groupname != NULL, NULL );
  if (groupname == NULL) {
    if (err) *err = E_PARAM_NULL;
    return NULL;
  }

  if (strlen(groupname) == 0 || strlen(groupname) >= HARD_GROUPNAME_LENGTH) {
    if (err) *err = E_PARAM_BIG;
    return NULL;
  }

  if (GetGroupByName(groupname) != NULL) {
    if (err) *err = E_PARAM_EXIST;
    return NULL;
  }

  /* homedir */
  if (context != NULL) {
    wzd_user_t * me;

    me = GetUserByID(context->userid);
    if (me != NULL && me->group_num > 0) {
      wzd_group_t * mygroup = GetGroupByID(me->groups[0]);
      homedir = mygroup->defaultpath;
    } else {
      homedir = me->rootpath;
    }

    /* check if homedir exist */
    {
      fs_filestat_t s;
      if (fs_file_stat(homedir,&s) || !S_ISDIR(s.mode)) {
        out_log(LEVEL_HIGH,"WARNING homedir %s does not exist (while creating group %s)\n",homedir,groupname);
      }
    }
  } else {
    out_log(LEVEL_HIGH,"WARNING could not get a default homedir for new group %s\n",groupname);
    /** \todo use a config parameter or a default group to get the
     * default path ?
     */
    homedir = "";
  }

  if (strlen(homedir) >= WZD_MAX_PATH) {
    out_log(LEVEL_HIGH,"ERROR homedir is too long (>= %d chars) while creating group %s\n",WZD_MAX_PATH,groupname);
    if (err) *err = E_PARAM_BIG;
    return NULL;
  }

  /* finally, create the new group */
  newgroup = group_allocate();
  strncpy(newgroup->groupname,groupname,HARD_GROUPNAME_LENGTH);
  strncpy(newgroup->defaultpath,homedir,WZD_MAX_PATH);

  return newgroup;
}

/** \brief Register a group to the main server
 * \return The gid of the registered group, or -1 on error
 */
gid_t group_register(wzd_group_t * group, u16_t backend_id)
{
  gid_t gid;

  WZD_ASSERT(group != NULL);
  if (group == NULL) return (gid_t)-1;

  WZD_ASSERT(group->gid != (gid_t)-1);
  if (group->gid == (gid_t)-1) return (gid_t)-1;

  /* safety check */
  if (group->gid >= INT_MAX) {
    out_log(LEVEL_HIGH, "ERROR group_register(gid=%d): gid too big\n",group->gid);
    return (gid_t)-1;
  }

  WZD_MUTEX_LOCK(SET_MUTEX_USER);

  gid = group->gid;

  if (gid >= _max_gid) {
    size_t size; /* size of extent */

    if (gid >= _max_gid + 255)
      size = gid - _max_gid;
    else
      size = 256;
    _group_array = wzd_realloc(_group_array, (_max_gid + size + 1)*sizeof(wzd_group_t*));
    memset(_group_array + _max_gid, 0, (size+1) * sizeof(wzd_group_t*));
    _max_gid = _max_gid + size;
  }

  if (_group_array[gid] != NULL) {
    out_log(LEVEL_NORMAL, "INFO group_register(gid=%d): another group is already present (%s)\n",gid,_group_array[gid]->groupname);
    WZD_MUTEX_UNLOCK(SET_MUTEX_USER);
    return -1;
  }

  _group_array[gid] = group;
  group->backend_id = backend_id;

  out_log(LEVEL_FLOOD,"DEBUG registered gid %d with backend %d\n",gid,backend_id);

  WZD_MUTEX_UNLOCK(SET_MUTEX_USER);
  return gid;
}

/** \brief Update a registered group atomically. Datas are copied,
 * and old group is freed.
 * A pointer to the old group is still valid (change is done in-place)
 * If the gid had changed, the group will be moved
 * \return 0 if ok
 */
int group_update(gid_t gid, wzd_group_t * new_group)
{
  wzd_group_t * buffer;

  if (gid == (gid_t)-1) return -1;
  if (gid > _max_gid) return -1;
  if (_group_array[gid] == NULL) return -2;

  if (gid != new_group->gid) {
    if (_group_array[new_group->gid] != NULL) return -3;
  }

  /* same group ? do nothing */
  if (gid == new_group->gid && _group_array[gid] == new_group) return 0;

  WZD_MUTEX_LOCK(SET_MUTEX_USER);
  /* backup old group */
  buffer = wzd_malloc(sizeof(wzd_group_t));
  *buffer = *_group_array[gid];
  /* update group */
  *_group_array[gid] = *new_group;
  group_free(buffer);
  if (gid != new_group->gid) {
    _group_array[new_group->gid] = _group_array[gid];
    _group_array[gid] = NULL;
  }
  WZD_MUTEX_UNLOCK(SET_MUTEX_USER);

  return 0;
}

/** \brief Unregister a group to the main server
 * The \a group struct must be freed using group_free()
 * \return The unregistered group structure, or NULL on error
 */
wzd_group_t * group_unregister(gid_t gid)
{
  wzd_group_t * group = NULL;

  WZD_ASSERT_RETURN(gid != (gid_t)-1, NULL);
  if (gid == (gid_t)-1) return NULL;

  if (gid > _max_gid) return NULL;

  WZD_MUTEX_LOCK(SET_MUTEX_USER);

  if (_group_array[gid] != NULL) {
    group = _group_array[gid];
    _group_array[gid] = NULL;
  }

  WZD_MUTEX_UNLOCK(SET_MUTEX_USER);
  out_log(LEVEL_FLOOD,"DEBUG unregistered gid %d\n",gid);

  return group;
}

/** \brief Free memory used to register groups
 * \warning Also free ALL registered groups !
 */
void group_free_registry(void)
{
  gid_t gid;
  WZD_MUTEX_LOCK(SET_MUTEX_USER);
  if (_group_array != NULL) {
    for (gid=0; gid<=_max_gid; gid++) {
      group_free(_group_array[gid]);
    }
  }
  wzd_free(_group_array);
  _group_array = NULL;
  _max_gid = 0;
  WZD_MUTEX_UNLOCK(SET_MUTEX_USER);
}

/** \brief Get registered group using the \a gid
 * \return The group, or NULL
 */
wzd_group_t * group_get_by_id(gid_t gid)
{
  if (gid == (gid_t)-1) return NULL;
  if (gid > _max_gid) return NULL;
  if (_max_gid == 0) return NULL;

  return _group_array[gid];
}

/** \brief Get registered group using the \a name
 * \return The group, or NULL
 * \todo Re-implement the function using a hash table
 */
wzd_group_t * group_get_by_name(const char * groupname)
{
  gid_t gid;

  if (groupname == NULL || strlen(groupname)<1 || _max_gid==0) return NULL;

  /* We don't need to lock the access since the _group_array can only grow */
  for (gid=0; gid<=_max_gid; gid++) {
    if (_group_array[gid] != NULL
        && _group_array[gid]->groupname != NULL
        && strcmp(groupname,_group_array[gid]->groupname)==0)
      return _group_array[gid];
  }
  return NULL;
}

/** \brief Get list or groups register for a specific backend
 * The returned list is terminated by -1, and must be freed with wzd_free()
 */
gid_t * group_get_list(u16_t backend_id)
{
  gid_t * gid_list = NULL;
  gid_t size;
  int index;
  gid_t gid;

  /** \todo XXX we should use locks (and be careful to avoid deadlocks) */

  /** \todo it would be better to get the real number of used gid */
  size = _max_gid;

  gid_list = (gid_t*)wzd_malloc((size+1)*sizeof(gid_t));
  index = 0;
  /* We don't need to lock the access since the _group_array can only grow */
  for (gid=0; gid<size; gid++) {
    if (_group_array[gid] != NULL
        && _group_array[gid]->gid != INVALID_USER)
      gid_list[index++] = _group_array[gid]->gid;
  }
  gid_list[index] = (gid_t)-1;
  gid_list[size] = (gid_t)-1;

  return gid_list;
}

/** \brief Find the first free gid, starting from \a start
 */
gid_t group_find_free_gid(gid_t start)
{
  gid_t gid;

  if (start == (gid_t)-1) start = 0;

  /** \todo locking may be harmful if this function is called from another
   * group_x() function
   */
/*  WZD_MUTEX_LOCK(SET_MUTEX_USER);*/
  for (gid = start; gid < _max_gid && gid != (gid_t)-1; gid++) {
    if (_group_array[gid] == NULL) break;
  }
/*  WZD_MUTEX_UNLOCK(SET_MUTEX_USER);*/

  return gid;
}

/** \brief Add an ip to the list of authorized/forbidden ips
 * \return 0 if ok
 */
int group_ip_add(wzd_group_t * group, const char * ip, int is_authorized)
{
  WZD_ASSERT( group != NULL );
  if (group == NULL) return -1;

  /** \note The number of stored ips per group is no more limited */

  return ip_add_check(&group->ip_list, ip, is_authorized);
}