trunk/src/hash.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2016 ircd-hybrid development team
 *
 *  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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 *  USA
 */

/*! \file hash.c
 * \brief Hash table management.
 * \version $Id$
 */

#include "stdinc.h"
#include "list.h"
#include "conf.h"
#include "channel.h"
#include "channel_mode.h"
#include "client.h"
#include "modules.h"
#include "hash.h"
#include "id.h"
#include "resv.h"
#include "rng_mt.h"
#include "userhost.h"
#include "irc_string.h"
#include "ircd.h"
#include "numeric.h"
#include "send.h"
#include "memory.h"
#include "mempool.h"
#include "dbuf.h"
#include "user.h"


static unsigned int hashf_xor_key;

/* The actual hash tables, They MUST be of the same HASHSIZE, variable
 * size tables could be supported but the rehash routine should also
 * rebuild the transformation maps, I kept the tables of equal size
 * so that I can use one hash function.
 */
static struct Client *idTable[HASHSIZE];
static struct Client *clientTable[HASHSIZE];
static struct Channel *channelTable[HASHSIZE];
static struct UserHost *userhostTable[HASHSIZE];


/* hash_init()
 *
 * inputs       - NONE
 * output       - NONE
 * side effects - Initialize the maps used by hash
 *                functions and clear the tables
 */
void
hash_init(void)
{
  do
    hashf_xor_key = genrand_int32() % 256;  /* better than nothing --adx */
  while (!hashf_xor_key);
}

/*
 * New hash function based on the Fowler/Noll/Vo (FNV) algorithm from
 * http://www.isthe.com/chongo/tech/comp/fnv/
 *
 * Here, we use the FNV-1 method, which gives slightly better results
 * than FNV-1a.   -Michael
 */
unsigned int
strhash(const char *name)
{
  const unsigned char *p = (const unsigned char *)name;
  unsigned int hval = FNV1_32_INIT;

  if (EmptyString(p))
    return 0;

  for (; *p; ++p)
  {
    hval += (hval << 1) + (hval <<  4) + (hval << 7) +
            (hval << 8) + (hval << 24);
    hval ^= (ToLower(*p) ^ hashf_xor_key);
  }

  return (hval >> FNV1_32_BITS) ^ (hval & ((1 << FNV1_32_BITS) - 1));
}

/************************** Externally visible functions ********************/

/* Optimization note: in these functions I supposed that the CSE optimization
 * (Common Subexpression Elimination) does its work decently, this means that
 * I avoided introducing new variables to do the work myself and I did let
 * the optimizer play with more free registers, actual tests proved this
 * solution to be faster than doing things like tmp2=tmp->hnext... and then
 * use tmp2 myself which would have given less freedom to the optimizer.
 */

/* hash_add_client()
 *
 * inputs       - pointer to client
 * output       - NONE
 * side effects - Adds a client's name in the proper hash linked
 *                list, can't fail, client_p must have a non-null
 *                name or expect a coredump, the name is infact
 *                taken from client_p->name
 */
void
hash_add_client(struct Client *client_p)
{
  const unsigned int hashv = strhash(client_p->name);

  client_p->hnext = clientTable[hashv];
  clientTable[hashv] = client_p;
}

/* hash_add_channel()
 *
 * inputs       - pointer to channel
 * output       - NONE
 * side effects - Adds a channel's name in the proper hash linked
 *                list, can't fail. chptr must have a non-null name
 *                or expect a coredump. As before the name is taken
 *                from chptr->name, we do hash its entire lenght
 *                since this proved to be statistically faster
 */
void
hash_add_channel(struct Channel *chptr)
{
  const unsigned int hashv = strhash(chptr->name);

  chptr->hnextch = channelTable[hashv];
  channelTable[hashv] = chptr;
}

void
hash_add_userhost(struct UserHost *userhost)
{
  const unsigned int hashv = strhash(userhost->host);

  userhost->next = userhostTable[hashv];
  userhostTable[hashv] = userhost;
}

void
hash_add_id(struct Client *client_p)
{
  const unsigned int hashv = strhash(client_p->id);

  client_p->idhnext = idTable[hashv];
  idTable[hashv] = client_p;
}

/* hash_del_id()
 *
 * inputs       - pointer to client
 * output       - NONE
 * side effects - Removes an ID from the hash linked list
 */
void
hash_del_id(struct Client *client_p)
{
  const unsigned int hashv = strhash(client_p->id);
  struct Client *tmp = idTable[hashv];

  if (tmp)
  {
    if (tmp == client_p)
    {
      idTable[hashv] = client_p->idhnext;
      client_p->idhnext = client_p;
    }
    else
    {
      while (tmp->idhnext != client_p)
        if ((tmp = tmp->idhnext) == NULL)
          return;

      tmp->idhnext = tmp->idhnext->idhnext;
      client_p->idhnext = client_p;
    }
  }
}

/* hash_del_client()
 *
 * inputs       - pointer to client
 * output       - NONE
 * side effects - Removes a Client's name from the hash linked list
 */
void
hash_del_client(struct Client *client_p)
{
  const unsigned int hashv = strhash(client_p->name);
  struct Client *tmp = clientTable[hashv];

  if (tmp)
  {
    if (tmp == client_p)
    {
      clientTable[hashv] = client_p->hnext;
      client_p->hnext = client_p;
    }
    else
    {
      while (tmp->hnext != client_p)
        if ((tmp = tmp->hnext) == NULL)
          return;

      tmp->hnext = tmp->hnext->hnext;
      client_p->hnext = client_p;
    }
  }
}

/* hash_del_userhost()
 *
 * inputs       - pointer to userhost
 * output       - NONE
 * side effects - Removes a userhost from the hash linked list
 */
void
hash_del_userhost(struct UserHost *userhost)
{
  const unsigned int hashv = strhash(userhost->host);
  struct UserHost *tmp = userhostTable[hashv];

  if (tmp)
  {
    if (tmp == userhost)
    {
      userhostTable[hashv] = userhost->next;
      userhost->next = userhost;
    }
    else
    {
      while (tmp->next != userhost)
        if ((tmp = tmp->next) == NULL)
          return;

      tmp->next = tmp->next->next;
      userhost->next = userhost;
    }
  }
}

/* hash_del_channel()
 *
 * inputs       - pointer to client
 * output       - NONE
 * side effects - Removes the channel's name from the corresponding
 *                hash linked list
 */
void
hash_del_channel(struct Channel *chptr)
{
  const unsigned int hashv = strhash(chptr->name);
  struct Channel *tmp = channelTable[hashv];

  if (tmp)
  {
    if (tmp == chptr)
    {
      channelTable[hashv] = chptr->hnextch;
      chptr->hnextch = chptr;
    }
    else
    {
      while (tmp->hnextch != chptr)
        if ((tmp = tmp->hnextch) == NULL)
          return;

      tmp->hnextch = tmp->hnextch->hnextch;
      chptr->hnextch = chptr;
    }
  }
}

/* hash_find_client()
 *
 * inputs       - pointer to name
 * output       - NONE
 * side effects - New semantics: finds a client whose name is 'name'
 *                if can't find one returns NULL. If it finds one moves
 *                it to the top of the list and returns it.
 */
struct Client *
hash_find_client(const char *name)
{
  const unsigned int hashv = strhash(name);
  struct Client *client_p;

  if ((client_p = clientTable[hashv]))
  {
    if (irccmp(name, client_p->name))
    {
      struct Client *prev;

      while (prev = client_p, (client_p = client_p->hnext))
      {
        if (!irccmp(name, client_p->name))
        {
          prev->hnext = client_p->hnext;
          client_p->hnext = clientTable[hashv];
          clientTable[hashv] = client_p;
          break;
        }
      }
    }
  }

  return client_p;
}

struct Client *
hash_find_id(const char *name)
{
  const unsigned int hashv = strhash(name);
  struct Client *client_p;

  if ((client_p = idTable[hashv]))
  {
    if (strcmp(name, client_p->id))
    {
      struct Client *prev;

      while (prev = client_p, (client_p = client_p->idhnext))
      {
        if (!strcmp(name, client_p->id))
        {
          prev->idhnext = client_p->idhnext;
          client_p->idhnext = idTable[hashv];
          idTable[hashv] = client_p;
          break;
        }
      }
    }
  }

  return client_p;
}

struct Client *
hash_find_server(const char *name)
{
  const unsigned int hashv = strhash(name);
  struct Client *client_p = NULL;

  if (IsDigit(*name) && strlen(name) == IRC_MAXSID)
    return hash_find_id(name);

  if ((client_p = clientTable[hashv]))
  {
    if ((!IsServer(client_p) && !IsMe(client_p)) ||
        irccmp(name, client_p->name))
    {
      struct Client *prev;

      while (prev = client_p, (client_p = client_p->hnext))
      {
        if ((IsServer(client_p) || IsMe(client_p)) &&
            !irccmp(name, client_p->name))
        {
          prev->hnext = client_p->hnext;
          client_p->hnext = clientTable[hashv];
          clientTable[hashv] = client_p;
          break;
        }
      }
    }
  }

  return client_p;
}

/* hash_find_channel()
 *
 * inputs       - pointer to name
 * output       - NONE
 * side effects - New semantics: finds a channel whose name is 'name',
 *                if can't find one returns NULL, if can find it moves
 *                it to the top of the list and returns it.
 */
struct Channel *
hash_find_channel(const char *name)
{
  const unsigned int hashv = strhash(name);
  struct Channel *chptr = NULL;

  if ((chptr = channelTable[hashv]))
  {
    if (irccmp(name, chptr->name))
    {
      struct Channel *prev;

      while (prev = chptr, (chptr = chptr->hnextch))
      {
        if (!irccmp(name, chptr->name))
        {
          prev->hnextch = chptr->hnextch;
          chptr->hnextch = channelTable[hashv];
          channelTable[hashv] = chptr;
          break;
        }
      }
    }
  }

  return chptr;
}

struct UserHost *
hash_find_userhost(const char *host)
{
  const unsigned int hashv = strhash(host);
  struct UserHost *userhost;

  if ((userhost = userhostTable[hashv]))
  {
    if (irccmp(host, userhost->host))
    {
      struct UserHost *prev;

      while (prev = userhost, (userhost = userhost->next))
      {
        if (!irccmp(host, userhost->host))
        {
          prev->next = userhost->next;
          userhost->next = userhostTable[hashv];
          userhostTable[hashv] = userhost;
          break;
        }
      }
    }
  }

  return userhost;
}

/* hash_get_bucket(int type, unsigned int hashv)
 *
 * inputs       - hash value (must be between 0 and HASHSIZE - 1)
 * output       - NONE
 * returns      - pointer to first channel in channelTable[hashv]
 *                if that exists;
 *                NULL if there is no channel in that place;
 *                NULL if hashv is an invalid number.
 * side effects - NONE
 */
void *
hash_get_bucket(int type, unsigned int hashv)
{
  assert(hashv < HASHSIZE);

  if (hashv >= HASHSIZE)
    return NULL;

  switch (type)
  {
    case HASH_TYPE_ID:
      return idTable[hashv];
      break;
    case HASH_TYPE_CHANNEL:
      return channelTable[hashv];
      break;
    case HASH_TYPE_CLIENT:
      return clientTable[hashv];
      break;
    case HASH_TYPE_USERHOST:
      return userhostTable[hashv];
      break;
    default:
      assert(0);
  }

  return NULL;
}

/*
 * Safe list code.
 *
 * The idea is really quite simple. As the link lists pointed to in
 * each "bucket" of the channel hash table are traversed atomically
 * there is no locking needed. Overall, yes, inconsistent reported
 * state can still happen, but normally this isn't a big deal.
 * I don't like sticking the code into hash.c but oh well. Moreover,
 * if a hash isn't used in future, oops.
 *
 * - Dianora
 */

/* exceeding_sendq()
 *
 * inputs       - pointer to client to check
 * output       - 1 if client is in danger of blowing its sendq
 *                0 if it is not.
 * side effects -
 *
 * Sendq limit is fairly conservative at 1/2 (In original anyway)
 */
static int
exceeding_sendq(const struct Client *to)
{
  if (dbuf_length(&to->connection->buf_sendq) > (get_sendq(&to->connection->confs) / 2))
    return 1;
  else
    return 0;
}

void
free_list_task(struct Client *source_p)
{
  struct ListTask *const lt = source_p->connection->list_task;
  dlink_node *node = NULL, *node_next = NULL;

  dlinkDelete(&lt->node, &listing_client_list);

  DLINK_FOREACH_SAFE(node, node_next, lt->show_mask.head)
  {
    xfree(node->data);
    free_dlink_node(node);
  }

  DLINK_FOREACH_SAFE(node, node_next, lt->hide_mask.head)
  {
    xfree(node->data);
    free_dlink_node(node);
  }

  xfree(lt);
  source_p->connection->list_task = NULL;
}

/* list_allow_channel()
 *
 * inputs       - channel name
 *              - pointer to a list task
 * output       - 1 if the channel is to be displayed
 *                0 otherwise
 * side effects -
 */
static int
list_allow_channel(const char *name, const struct ListTask *lt)
{
  const dlink_node *node = NULL;

  DLINK_FOREACH(node, lt->show_mask.head)
    if (match(node->data, name) != 0)
      return 0;

  DLINK_FOREACH(node, lt->hide_mask.head)
    if (match(node->data, name) == 0)
      return 0;

  return 1;
}

/* list_one_channel()
 *
 * inputs       - client pointer to return result to
 *              - pointer to channel to list
 *              - pointer to ListTask structure
 * output       - none
 * side effects -
 */
static void
list_one_channel(struct Client *source_p, struct Channel *chptr)
{
  const struct ListTask *const lt = source_p->connection->list_task;
  char listbuf[MODEBUFLEN] = "";
  char modebuf[MODEBUFLEN] = "";
  char parabuf[MODEBUFLEN] = "";

  if (SecretChannel(chptr) &&
      !(HasUMode(source_p, UMODE_ADMIN) || IsMember(source_p, chptr)))
    return;

  if (dlink_list_length(&chptr->members) < lt->users_min ||
      dlink_list_length(&chptr->members) > lt->users_max ||
      (chptr->creationtime != 0 &&
       ((unsigned int)chptr->creationtime < lt->created_min ||
        (unsigned int)chptr->creationtime > lt->created_max)) ||
      (unsigned int)chptr->topic_time < lt->topicts_min ||
      (chptr->topic_time ? (unsigned int)chptr->topic_time : UINT_MAX) >
      lt->topicts_max)
    return;

  if (lt->topic[0] && match(lt->topic, chptr->topic))
    return;

  if (!list_allow_channel(chptr->name, lt))
    return;

  channel_modes(chptr, source_p, modebuf, parabuf);

  if (chptr->topic[0])
    snprintf(listbuf, sizeof(listbuf), "[%s] ", modebuf);
  else
    snprintf(listbuf, sizeof(listbuf), "[%s]",  modebuf);

  sendto_one_numeric(source_p, &me, RPL_LIST, chptr->name,
                     dlink_list_length(&chptr->members),
                     listbuf, chptr->topic);
}

/* safe_list_channels()
 *
 * inputs       - pointer to client requesting list
 * output       - 0/1
 * side effects - safely list all channels to source_p
 *
 * Walk the channel buckets, ensure all pointers in a bucket are
 * traversed before blocking on a sendq. This means, no locking is needed.
 *
 * - Dianora
 */
void
safe_list_channels(struct Client *source_p, int only_unmasked_channels)
{
  struct ListTask *const lt = source_p->connection->list_task;
  struct Channel *chptr = NULL;

  if (!only_unmasked_channels)
  {
    for (unsigned int i = lt->hash_index; i < HASHSIZE; ++i)
    {
      if (exceeding_sendq(source_p))
      {
        lt->hash_index = i;
        return;  /* Still more to do */
      }

      for (chptr = channelTable[i]; chptr; chptr = chptr->hnextch)
        list_one_channel(source_p, chptr);
    }
  }
  else
  {
    dlink_node *node = NULL;

    DLINK_FOREACH(node, lt->show_mask.head)
      if ((chptr = hash_find_channel(node->data)))
        list_one_channel(source_p, chptr);
  }

  free_list_task(source_p);
  sendto_one_numeric(source_p, &me, RPL_LISTEND);
}
Revision:	7032
Committed:	Sun Jan 3 14:34:39 2016 UTC (9 years, 7 months ago) by michael
Content type:	text/x-csrc
File size:	16163 byte(s)
Log Message:	- Renamed MyCalloc to xcalloc
#	User	Rev	Content
1	adx	30	/*
2	michael	2916	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	adx	30	*
4	michael	7006	* Copyright (c) 1997-2016 ircd-hybrid development team
5	adx	30	*
6			* This program is free software; you can redistribute it and/or modify
7			* it under the terms of the GNU General Public License as published by
8			* the Free Software Foundation; either version 2 of the License, or
9			* (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18	michael	4565	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	adx	30	* USA
20			*/
21
22	michael	2916	/*! \file hash.c
23			* \brief Hash table management.
24			* \version $Id$
25			*/
26
27	adx	30	#include "stdinc.h"
28	michael	1011	#include "list.h"
29	michael	1309	#include "conf.h"
30	adx	30	#include "channel.h"
31			#include "channel_mode.h"
32			#include "client.h"
33			#include "modules.h"
34			#include "hash.h"
35	michael	6161	#include "id.h"
36	adx	30	#include "resv.h"
37	michael	982	#include "rng_mt.h"
38	adx	30	#include "userhost.h"
39			#include "irc_string.h"
40			#include "ircd.h"
41			#include "numeric.h"
42			#include "send.h"
43			#include "memory.h"
44	michael	1654	#include "mempool.h"
45	adx	30	#include "dbuf.h"
46	michael	3347	#include "user.h"
47	adx	30
48
49	michael	5460	static unsigned int hashf_xor_key;
50	adx	30
51			/* The actual hash tables, They MUST be of the same HASHSIZE, variable
52			* size tables could be supported but the rehash routine should also
53	michael	2916	* rebuild the transformation maps, I kept the tables of equal size
54	adx	30	* so that I can use one hash function.
55			*/
56			static struct Client *idTable[HASHSIZE];
57			static struct Client *clientTable[HASHSIZE];
58			static struct Channel *channelTable[HASHSIZE];
59			static struct UserHost *userhostTable[HASHSIZE];
60
61
62	michael	6393	/* hash_init()
63	adx	30	*
64			* inputs - NONE
65			* output - NONE
66			* side effects - Initialize the maps used by hash
67			* functions and clear the tables
68			*/
69			void
70	michael	1798	hash_init(void)
71	adx	30	{
72	michael	7031	do
73			hashf_xor_key = genrand_int32() % 256; /* better than nothing --adx */
74			while (!hashf_xor_key);
75	adx	30	}
76
77			/*
78			* New hash function based on the Fowler/Noll/Vo (FNV) algorithm from
79			* http://www.isthe.com/chongo/tech/comp/fnv/
80			*
81			* Here, we use the FNV-1 method, which gives slightly better results
82			* than FNV-1a. -Michael
83			*/
84			unsigned int
85			strhash(const char *name)
86			{
87			const unsigned char p = (const unsigned char )name;
88			unsigned int hval = FNV1_32_INIT;
89
90	michael	1826	if (EmptyString(p))
91	adx	30	return 0;
92	michael	4890
93			for (; *p; ++p)
94	adx	30	{
95			hval += (hval << 1) + (hval << 4) + (hval << 7) +
96			(hval << 8) + (hval << 24);
97	michael	982	hval ^= (ToLower(*p) ^ hashf_xor_key);
98	adx	30	}
99
100	michael	982	return (hval >> FNV1_32_BITS) ^ (hval & ((1 << FNV1_32_BITS) - 1));
101	adx	30	}
102
103			/************************ Externally visible functions ******************/
104
105			/* Optimization note: in these functions I supposed that the CSE optimization
106			* (Common Subexpression Elimination) does its work decently, this means that
107			* I avoided introducing new variables to do the work myself and I did let
108			* the optimizer play with more free registers, actual tests proved this
109			* solution to be faster than doing things like tmp2=tmp->hnext... and then
110			* use tmp2 myself which would have given less freedom to the optimizer.
111			*/
112
113			/* hash_add_client()
114			*
115			* inputs - pointer to client
116			* output - NONE
117			* side effects - Adds a client's name in the proper hash linked
118			* list, can't fail, client_p must have a non-null
119			* name or expect a coredump, the name is infact
120			* taken from client_p->name
121			*/
122			void
123			hash_add_client(struct Client *client_p)
124			{
125	michael	4977	const unsigned int hashv = strhash(client_p->name);
126	adx	30
127			client_p->hnext = clientTable[hashv];
128			clientTable[hashv] = client_p;
129			}
130
131			/* hash_add_channel()
132			*
133			* inputs - pointer to channel
134			* output - NONE
135			* side effects - Adds a channel's name in the proper hash linked
136			* list, can't fail. chptr must have a non-null name
137			* or expect a coredump. As before the name is taken
138			* from chptr->name, we do hash its entire lenght
139			* since this proved to be statistically faster
140			*/
141			void
142			hash_add_channel(struct Channel *chptr)
143			{
144	michael	4977	const unsigned int hashv = strhash(chptr->name);
145	adx	30
146			chptr->hnextch = channelTable[hashv];
147			channelTable[hashv] = chptr;
148			}
149
150			void
151			hash_add_userhost(struct UserHost *userhost)
152			{
153	michael	4977	const unsigned int hashv = strhash(userhost->host);
154	adx	30
155			userhost->next = userhostTable[hashv];
156			userhostTable[hashv] = userhost;
157			}
158
159			void
160			hash_add_id(struct Client *client_p)
161			{
162	michael	4977	const unsigned int hashv = strhash(client_p->id);
163	adx	30
164			client_p->idhnext = idTable[hashv];
165			idTable[hashv] = client_p;
166			}
167
168			/* hash_del_id()
169			*
170			* inputs - pointer to client
171			* output - NONE
172			* side effects - Removes an ID from the hash linked list
173			*/
174			void
175			hash_del_id(struct Client *client_p)
176			{
177	michael	4977	const unsigned int hashv = strhash(client_p->id);
178	adx	30	struct Client *tmp = idTable[hashv];
179
180	michael	3241	if (tmp)
181	adx	30	{
182			if (tmp == client_p)
183			{
184			idTable[hashv] = client_p->idhnext;
185			client_p->idhnext = client_p;
186			}
187			else
188			{
189			while (tmp->idhnext != client_p)
190			if ((tmp = tmp->idhnext) == NULL)
191			return;
192
193			tmp->idhnext = tmp->idhnext->idhnext;
194			client_p->idhnext = client_p;
195			}
196			}
197			}
198
199			/* hash_del_client()
200			*
201			* inputs - pointer to client
202			* output - NONE
203			* side effects - Removes a Client's name from the hash linked list
204			*/
205			void
206			hash_del_client(struct Client *client_p)
207			{
208	michael	4977	const unsigned int hashv = strhash(client_p->name);
209	adx	30	struct Client *tmp = clientTable[hashv];
210
211	michael	3241	if (tmp)
212	adx	30	{
213			if (tmp == client_p)
214			{
215			clientTable[hashv] = client_p->hnext;
216			client_p->hnext = client_p;
217			}
218			else
219			{
220			while (tmp->hnext != client_p)
221			if ((tmp = tmp->hnext) == NULL)
222			return;
223
224			tmp->hnext = tmp->hnext->hnext;
225			client_p->hnext = client_p;
226			}
227			}
228			}
229
230			/* hash_del_userhost()
231			*
232			* inputs - pointer to userhost
233			* output - NONE
234			* side effects - Removes a userhost from the hash linked list
235			*/
236			void
237			hash_del_userhost(struct UserHost *userhost)
238			{
239	michael	4977	const unsigned int hashv = strhash(userhost->host);
240	adx	30	struct UserHost *tmp = userhostTable[hashv];
241
242	michael	3241	if (tmp)
243	adx	30	{
244			if (tmp == userhost)
245			{
246			userhostTable[hashv] = userhost->next;
247			userhost->next = userhost;
248			}
249			else
250			{
251			while (tmp->next != userhost)
252			if ((tmp = tmp->next) == NULL)
253			return;
254
255			tmp->next = tmp->next->next;
256			userhost->next = userhost;
257			}
258			}
259			}
260
261			/* hash_del_channel()
262			*
263			* inputs - pointer to client
264			* output - NONE
265			* side effects - Removes the channel's name from the corresponding
266			* hash linked list
267			*/
268			void
269			hash_del_channel(struct Channel *chptr)
270			{
271	michael	4977	const unsigned int hashv = strhash(chptr->name);
272	adx	30	struct Channel *tmp = channelTable[hashv];
273
274	michael	3241	if (tmp)
275	adx	30	{
276			if (tmp == chptr)
277			{
278			channelTable[hashv] = chptr->hnextch;
279			chptr->hnextch = chptr;
280			}
281			else
282			{
283			while (tmp->hnextch != chptr)
284			if ((tmp = tmp->hnextch) == NULL)
285			return;
286
287			tmp->hnextch = tmp->hnextch->hnextch;
288			chptr->hnextch = chptr;
289			}
290			}
291			}
292
293	michael	1169	/* hash_find_client()
294	adx	30	*
295			* inputs - pointer to name
296			* output - NONE
297			* side effects - New semantics: finds a client whose name is 'name'
298			* if can't find one returns NULL. If it finds one moves
299			* it to the top of the list and returns it.
300			*/
301			struct Client *
302	michael	1169	hash_find_client(const char *name)
303	adx	30	{
304	michael	4977	const unsigned int hashv = strhash(name);
305	adx	30	struct Client *client_p;
306
307	michael	3241	if ((client_p = clientTable[hashv]))
308	adx	30	{
309			if (irccmp(name, client_p->name))
310			{
311			struct Client *prev;
312
313	michael	3241	while (prev = client_p, (client_p = client_p->hnext))
314	adx	30	{
315			if (!irccmp(name, client_p->name))
316			{
317			prev->hnext = client_p->hnext;
318			client_p->hnext = clientTable[hashv];
319			clientTable[hashv] = client_p;
320			break;
321			}
322			}
323			}
324			}
325
326			return client_p;
327			}
328
329			struct Client *
330			hash_find_id(const char *name)
331			{
332	michael	4977	const unsigned int hashv = strhash(name);
333	adx	30	struct Client *client_p;
334
335	michael	3242	if ((client_p = idTable[hashv]))
336	adx	30	{
337	michael	880	if (strcmp(name, client_p->id))
338	adx	30	{
339			struct Client *prev;
340
341	michael	3242	while (prev = client_p, (client_p = client_p->idhnext))
342	adx	30	{
343	michael	880	if (!strcmp(name, client_p->id))
344	adx	30	{
345			prev->idhnext = client_p->idhnext;
346			client_p->idhnext = idTable[hashv];
347			idTable[hashv] = client_p;
348			break;
349			}
350			}
351			}
352			}
353
354			return client_p;
355			}
356
357			struct Client *
358	michael	1169	hash_find_server(const char *name)
359	adx	30	{
360	michael	4977	const unsigned int hashv = strhash(name);
361	adx	30	struct Client *client_p = NULL;
362
363			if (IsDigit(*name) && strlen(name) == IRC_MAXSID)
364	michael	1397	return hash_find_id(name);
365	adx	30
366	michael	3242	if ((client_p = clientTable[hashv]))
367	adx	30	{
368			if ((!IsServer(client_p) && !IsMe(client_p)) \|\|
369			irccmp(name, client_p->name))
370			{
371			struct Client *prev;
372
373	michael	3242	while (prev = client_p, (client_p = client_p->hnext))
374	adx	30	{
375			if ((IsServer(client_p) \|\| IsMe(client_p)) &&
376			!irccmp(name, client_p->name))
377			{
378			prev->hnext = client_p->hnext;
379			client_p->hnext = clientTable[hashv];
380			clientTable[hashv] = client_p;
381			break;
382			}
383			}
384			}
385			}
386
387	michael	1118	return client_p;
388	adx	30	}
389
390			/* hash_find_channel()
391			*
392			* inputs - pointer to name
393			* output - NONE
394	michael	2916	* side effects - New semantics: finds a channel whose name is 'name',
395	adx	30	* if can't find one returns NULL, if can find it moves
396			* it to the top of the list and returns it.
397			*/
398			struct Channel *
399			hash_find_channel(const char *name)
400			{
401	michael	4977	const unsigned int hashv = strhash(name);
402	adx	30	struct Channel *chptr = NULL;
403
404	michael	3242	if ((chptr = channelTable[hashv]))
405	adx	30	{
406	michael	4618	if (irccmp(name, chptr->name))
407	adx	30	{
408			struct Channel *prev;
409
410	michael	3242	while (prev = chptr, (chptr = chptr->hnextch))
411	adx	30	{
412	michael	4618	if (!irccmp(name, chptr->name))
413	adx	30	{
414			prev->hnextch = chptr->hnextch;
415			chptr->hnextch = channelTable[hashv];
416			channelTable[hashv] = chptr;
417			break;
418			}
419			}
420			}
421			}
422
423			return chptr;
424			}
425
426	michael	6393	struct UserHost *
427			hash_find_userhost(const char *host)
428			{
429			const unsigned int hashv = strhash(host);
430			struct UserHost *userhost;
431
432			if ((userhost = userhostTable[hashv]))
433			{
434			if (irccmp(host, userhost->host))
435			{
436			struct UserHost *prev;
437
438			while (prev = userhost, (userhost = userhost->next))
439			{
440			if (!irccmp(host, userhost->host))
441			{
442			prev->next = userhost->next;
443			userhost->next = userhostTable[hashv];
444			userhostTable[hashv] = userhost;
445			break;
446			}
447			}
448			}
449			}
450
451			return userhost;
452			}
453
454	adx	30	/* hash_get_bucket(int type, unsigned int hashv)
455			*
456			* inputs - hash value (must be between 0 and HASHSIZE - 1)
457			* output - NONE
458			* returns - pointer to first channel in channelTable[hashv]
459			* if that exists;
460			* NULL if there is no channel in that place;
461			* NULL if hashv is an invalid number.
462			* side effects - NONE
463			*/
464			void *
465			hash_get_bucket(int type, unsigned int hashv)
466			{
467			assert(hashv < HASHSIZE);
468	michael	4977
469	adx	30	if (hashv >= HASHSIZE)
470	michael	6393	return NULL;
471	adx	30
472			switch (type)
473			{
474			case HASH_TYPE_ID:
475			return idTable[hashv];
476			break;
477			case HASH_TYPE_CHANNEL:
478			return channelTable[hashv];
479			break;
480			case HASH_TYPE_CLIENT:
481			return clientTable[hashv];
482			break;
483			case HASH_TYPE_USERHOST:
484			return userhostTable[hashv];
485			break;
486			default:
487			assert(0);
488			}
489
490			return NULL;
491			}
492
493			/*
494			* Safe list code.
495			*
496			* The idea is really quite simple. As the link lists pointed to in
497			* each "bucket" of the channel hash table are traversed atomically
498			* there is no locking needed. Overall, yes, inconsistent reported
499			* state can still happen, but normally this isn't a big deal.
500			* I don't like sticking the code into hash.c but oh well. Moreover,
501			* if a hash isn't used in future, oops.
502			*
503			* - Dianora
504			*/
505
506			/* exceeding_sendq()
507			*
508			* inputs - pointer to client to check
509			* output - 1 if client is in danger of blowing its sendq
510			* 0 if it is not.
511			* side effects -
512			*
513			* Sendq limit is fairly conservative at 1/2 (In original anyway)
514			*/
515			static int
516	michael	2757	exceeding_sendq(const struct Client *to)
517	adx	30	{
518	michael	4588	if (dbuf_length(&to->connection->buf_sendq) > (get_sendq(&to->connection->confs) / 2))
519	adx	30	return 1;
520			else
521			return 0;
522			}
523
524			void
525	michael	3289	free_list_task(struct Client *source_p)
526	adx	30	{
527	michael	4870	struct ListTask *const lt = source_p->connection->list_task;
528	michael	4815	dlink_node node = NULL, node_next = NULL;
529	adx	30
530	michael	6385	dlinkDelete(&lt->node, &listing_client_list);
531	adx	30
532	michael	4815	DLINK_FOREACH_SAFE(node, node_next, lt->show_mask.head)
533	adx	30	{
534	michael	7032	xfree(node->data);
535	michael	4815	free_dlink_node(node);
536	adx	30	}
537
538	michael	4815	DLINK_FOREACH_SAFE(node, node_next, lt->hide_mask.head)
539	adx	30	{
540	michael	7032	xfree(node->data);
541	michael	4815	free_dlink_node(node);
542	adx	30	}
543
544	michael	7032	xfree(lt);
545	michael	4868	source_p->connection->list_task = NULL;
546	adx	30	}
547
548			/* list_allow_channel()
549			*
550			* inputs - channel name
551			* - pointer to a list task
552			* output - 1 if the channel is to be displayed
553			* 0 otherwise
554			* side effects -
555			*/
556			static int
557	michael	4618	list_allow_channel(const char name, const struct ListTask lt)
558	adx	30	{
559	michael	4815	const dlink_node *node = NULL;
560	adx	30
561	michael	4815	DLINK_FOREACH(node, lt->show_mask.head)
562			if (match(node->data, name) != 0)
563	adx	30	return 0;
564
565	michael	4815	DLINK_FOREACH(node, lt->hide_mask.head)
566			if (match(node->data, name) == 0)
567	adx	30	return 0;
568
569			return 1;
570			}
571
572			/* list_one_channel()
573			*
574			* inputs - client pointer to return result to
575			* - pointer to channel to list
576			* - pointer to ListTask structure
577			* output - none
578			* side effects -
579			*/
580			static void
581	michael	3288	list_one_channel(struct Client source_p, struct Channel chptr)
582	adx	30	{
583	michael	4870	const struct ListTask *const lt = source_p->connection->list_task;
584	michael	2616	char listbuf[MODEBUFLEN] = "";
585			char modebuf[MODEBUFLEN] = "";
586			char parabuf[MODEBUFLEN] = "";
587
588	michael	2495	if (SecretChannel(chptr) &&
589	michael	3428	!(HasUMode(source_p, UMODE_ADMIN) \|\| IsMember(source_p, chptr)))
590	adx	30	return;
591	michael	4890
592	michael	3288	if (dlink_list_length(&chptr->members) < lt->users_min \|\|
593			dlink_list_length(&chptr->members) > lt->users_max \|\|
594	michael	4818	(chptr->creationtime != 0 &&
595			((unsigned int)chptr->creationtime < lt->created_min \|\|
596			(unsigned int)chptr->creationtime > lt->created_max)) \|\|
597	michael	3288	(unsigned int)chptr->topic_time < lt->topicts_min \|\|
598	adx	30	(chptr->topic_time ? (unsigned int)chptr->topic_time : UINT_MAX) >
599	michael	3288	lt->topicts_max)
600	adx	30	return;
601
602	michael	4489	if (lt->topic[0] && match(lt->topic, chptr->topic))
603			return;
604
605	michael	4618	if (!list_allow_channel(chptr->name, lt))
606	adx	30	return;
607	michael	2616
608	michael	4486	channel_modes(chptr, source_p, modebuf, parabuf);
609	michael	2616
610	michael	4486	if (chptr->topic[0])
611			snprintf(listbuf, sizeof(listbuf), "[%s] ", modebuf);
612			else
613			snprintf(listbuf, sizeof(listbuf), "[%s]", modebuf);
614	michael	2616
615	michael	4618	sendto_one_numeric(source_p, &me, RPL_LIST, chptr->name,
616	michael	3109	dlink_list_length(&chptr->members),
617			listbuf, chptr->topic);
618	adx	30	}
619
620			/* safe_list_channels()
621			*
622			* inputs - pointer to client requesting list
623			* output - 0/1
624			* side effects - safely list all channels to source_p
625			*
626			* Walk the channel buckets, ensure all pointers in a bucket are
627			* traversed before blocking on a sendq. This means, no locking is needed.
628			*
629			* - Dianora
630			*/
631			void
632	michael	3288	safe_list_channels(struct Client *source_p, int only_unmasked_channels)
633	adx	30	{
634	michael	4870	struct ListTask *const lt = source_p->connection->list_task;
635	adx	30	struct Channel *chptr = NULL;
636
637			if (!only_unmasked_channels)
638			{
639	michael	3288	for (unsigned int i = lt->hash_index; i < HASHSIZE; ++i)
640	adx	30	{
641	michael	3291	if (exceeding_sendq(source_p))
642	adx	30	{
643	michael	3288	lt->hash_index = i;
644			return; /* Still more to do */
645	adx	30	}
646
647			for (chptr = channelTable[i]; chptr; chptr = chptr->hnextch)
648	michael	3288	list_one_channel(source_p, chptr);
649	adx	30	}
650			}
651			else
652			{
653	michael	4815	dlink_node *node = NULL;
654	adx	30
655	michael	4815	DLINK_FOREACH(node, lt->show_mask.head)
656			if ((chptr = hash_find_channel(node->data)))
657	michael	3288	list_one_channel(source_p, chptr);
658	adx	30	}
659
660	michael	3289	free_list_task(source_p);
661	michael	3109	sendto_one_numeric(source_p, &me, RPL_LISTEND);
662	adx	30	}