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 "hash.h"
#include "id.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 "dbuf.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:	7484
Committed:	Wed Mar 16 09:28:14 2016 UTC (9 years, 5 months ago) by michael
Content type:	text/x-csrc
File size:	16085 byte(s)
Log Message:	- hash.c: remove unused header includes
#	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 "hash.h"
34	michael	6161	#include "id.h"
35	michael	982	#include "rng_mt.h"
36	adx	30	#include "userhost.h"
37			#include "irc_string.h"
38			#include "ircd.h"
39			#include "numeric.h"
40			#include "send.h"
41			#include "memory.h"
42			#include "dbuf.h"
43
44
45	michael	5460	static unsigned int hashf_xor_key;
46	adx	30
47			/* The actual hash tables, They MUST be of the same HASHSIZE, variable
48			* size tables could be supported but the rehash routine should also
49	michael	2916	* rebuild the transformation maps, I kept the tables of equal size
50	adx	30	* so that I can use one hash function.
51			*/
52			static struct Client *idTable[HASHSIZE];
53			static struct Client *clientTable[HASHSIZE];
54			static struct Channel *channelTable[HASHSIZE];
55			static struct UserHost *userhostTable[HASHSIZE];
56
57
58	michael	6393	/* hash_init()
59	adx	30	*
60			* inputs - NONE
61			* output - NONE
62			* side effects - Initialize the maps used by hash
63			* functions and clear the tables
64			*/
65			void
66	michael	1798	hash_init(void)
67	adx	30	{
68	michael	7031	do
69			hashf_xor_key = genrand_int32() % 256; /* better than nothing --adx */
70			while (!hashf_xor_key);
71	adx	30	}
72
73			/*
74			* New hash function based on the Fowler/Noll/Vo (FNV) algorithm from
75			* http://www.isthe.com/chongo/tech/comp/fnv/
76			*
77			* Here, we use the FNV-1 method, which gives slightly better results
78			* than FNV-1a. -Michael
79			*/
80			unsigned int
81			strhash(const char *name)
82			{
83			const unsigned char p = (const unsigned char )name;
84			unsigned int hval = FNV1_32_INIT;
85
86	michael	1826	if (EmptyString(p))
87	adx	30	return 0;
88	michael	4890
89			for (; *p; ++p)
90	adx	30	{
91			hval += (hval << 1) + (hval << 4) + (hval << 7) +
92			(hval << 8) + (hval << 24);
93	michael	982	hval ^= (ToLower(*p) ^ hashf_xor_key);
94	adx	30	}
95
96	michael	982	return (hval >> FNV1_32_BITS) ^ (hval & ((1 << FNV1_32_BITS) - 1));
97	adx	30	}
98
99			/************************ Externally visible functions ******************/
100
101			/* Optimization note: in these functions I supposed that the CSE optimization
102			* (Common Subexpression Elimination) does its work decently, this means that
103			* I avoided introducing new variables to do the work myself and I did let
104			* the optimizer play with more free registers, actual tests proved this
105			* solution to be faster than doing things like tmp2=tmp->hnext... and then
106			* use tmp2 myself which would have given less freedom to the optimizer.
107			*/
108
109			/* hash_add_client()
110			*
111			* inputs - pointer to client
112			* output - NONE
113			* side effects - Adds a client's name in the proper hash linked
114			* list, can't fail, client_p must have a non-null
115			* name or expect a coredump, the name is infact
116			* taken from client_p->name
117			*/
118			void
119			hash_add_client(struct Client *client_p)
120			{
121	michael	4977	const unsigned int hashv = strhash(client_p->name);
122	adx	30
123			client_p->hnext = clientTable[hashv];
124			clientTable[hashv] = client_p;
125			}
126
127			/* hash_add_channel()
128			*
129			* inputs - pointer to channel
130			* output - NONE
131			* side effects - Adds a channel's name in the proper hash linked
132			* list, can't fail. chptr must have a non-null name
133			* or expect a coredump. As before the name is taken
134			* from chptr->name, we do hash its entire lenght
135			* since this proved to be statistically faster
136			*/
137			void
138			hash_add_channel(struct Channel *chptr)
139			{
140	michael	4977	const unsigned int hashv = strhash(chptr->name);
141	adx	30
142			chptr->hnextch = channelTable[hashv];
143			channelTable[hashv] = chptr;
144			}
145
146			void
147			hash_add_userhost(struct UserHost *userhost)
148			{
149	michael	4977	const unsigned int hashv = strhash(userhost->host);
150	adx	30
151			userhost->next = userhostTable[hashv];
152			userhostTable[hashv] = userhost;
153			}
154
155			void
156			hash_add_id(struct Client *client_p)
157			{
158	michael	4977	const unsigned int hashv = strhash(client_p->id);
159	adx	30
160			client_p->idhnext = idTable[hashv];
161			idTable[hashv] = client_p;
162			}
163
164			/* hash_del_id()
165			*
166			* inputs - pointer to client
167			* output - NONE
168			* side effects - Removes an ID from the hash linked list
169			*/
170			void
171			hash_del_id(struct Client *client_p)
172			{
173	michael	4977	const unsigned int hashv = strhash(client_p->id);
174	adx	30	struct Client *tmp = idTable[hashv];
175
176	michael	3241	if (tmp)
177	adx	30	{
178			if (tmp == client_p)
179			{
180			idTable[hashv] = client_p->idhnext;
181			client_p->idhnext = client_p;
182			}
183			else
184			{
185			while (tmp->idhnext != client_p)
186			if ((tmp = tmp->idhnext) == NULL)
187			return;
188
189			tmp->idhnext = tmp->idhnext->idhnext;
190			client_p->idhnext = client_p;
191			}
192			}
193			}
194
195			/* hash_del_client()
196			*
197			* inputs - pointer to client
198			* output - NONE
199			* side effects - Removes a Client's name from the hash linked list
200			*/
201			void
202			hash_del_client(struct Client *client_p)
203			{
204	michael	4977	const unsigned int hashv = strhash(client_p->name);
205	adx	30	struct Client *tmp = clientTable[hashv];
206
207	michael	3241	if (tmp)
208	adx	30	{
209			if (tmp == client_p)
210			{
211			clientTable[hashv] = client_p->hnext;
212			client_p->hnext = client_p;
213			}
214			else
215			{
216			while (tmp->hnext != client_p)
217			if ((tmp = tmp->hnext) == NULL)
218			return;
219
220			tmp->hnext = tmp->hnext->hnext;
221			client_p->hnext = client_p;
222			}
223			}
224			}
225
226			/* hash_del_userhost()
227			*
228			* inputs - pointer to userhost
229			* output - NONE
230			* side effects - Removes a userhost from the hash linked list
231			*/
232			void
233			hash_del_userhost(struct UserHost *userhost)
234			{
235	michael	4977	const unsigned int hashv = strhash(userhost->host);
236	adx	30	struct UserHost *tmp = userhostTable[hashv];
237
238	michael	3241	if (tmp)
239	adx	30	{
240			if (tmp == userhost)
241			{
242			userhostTable[hashv] = userhost->next;
243			userhost->next = userhost;
244			}
245			else
246			{
247			while (tmp->next != userhost)
248			if ((tmp = tmp->next) == NULL)
249			return;
250
251			tmp->next = tmp->next->next;
252			userhost->next = userhost;
253			}
254			}
255			}
256
257			/* hash_del_channel()
258			*
259			* inputs - pointer to client
260			* output - NONE
261			* side effects - Removes the channel's name from the corresponding
262			* hash linked list
263			*/
264			void
265			hash_del_channel(struct Channel *chptr)
266			{
267	michael	4977	const unsigned int hashv = strhash(chptr->name);
268	adx	30	struct Channel *tmp = channelTable[hashv];
269
270	michael	3241	if (tmp)
271	adx	30	{
272			if (tmp == chptr)
273			{
274			channelTable[hashv] = chptr->hnextch;
275			chptr->hnextch = chptr;
276			}
277			else
278			{
279			while (tmp->hnextch != chptr)
280			if ((tmp = tmp->hnextch) == NULL)
281			return;
282
283			tmp->hnextch = tmp->hnextch->hnextch;
284			chptr->hnextch = chptr;
285			}
286			}
287			}
288
289	michael	1169	/* hash_find_client()
290	adx	30	*
291			* inputs - pointer to name
292			* output - NONE
293			* side effects - New semantics: finds a client whose name is 'name'
294			* if can't find one returns NULL. If it finds one moves
295			* it to the top of the list and returns it.
296			*/
297			struct Client *
298	michael	1169	hash_find_client(const char *name)
299	adx	30	{
300	michael	4977	const unsigned int hashv = strhash(name);
301	adx	30	struct Client *client_p;
302
303	michael	3241	if ((client_p = clientTable[hashv]))
304	adx	30	{
305			if (irccmp(name, client_p->name))
306			{
307			struct Client *prev;
308
309	michael	3241	while (prev = client_p, (client_p = client_p->hnext))
310	adx	30	{
311			if (!irccmp(name, client_p->name))
312			{
313			prev->hnext = client_p->hnext;
314			client_p->hnext = clientTable[hashv];
315			clientTable[hashv] = client_p;
316			break;
317			}
318			}
319			}
320			}
321
322			return client_p;
323			}
324
325			struct Client *
326			hash_find_id(const char *name)
327			{
328	michael	4977	const unsigned int hashv = strhash(name);
329	adx	30	struct Client *client_p;
330
331	michael	3242	if ((client_p = idTable[hashv]))
332	adx	30	{
333	michael	880	if (strcmp(name, client_p->id))
334	adx	30	{
335			struct Client *prev;
336
337	michael	3242	while (prev = client_p, (client_p = client_p->idhnext))
338	adx	30	{
339	michael	880	if (!strcmp(name, client_p->id))
340	adx	30	{
341			prev->idhnext = client_p->idhnext;
342			client_p->idhnext = idTable[hashv];
343			idTable[hashv] = client_p;
344			break;
345			}
346			}
347			}
348			}
349
350			return client_p;
351			}
352
353			struct Client *
354	michael	1169	hash_find_server(const char *name)
355	adx	30	{
356	michael	4977	const unsigned int hashv = strhash(name);
357	adx	30	struct Client *client_p = NULL;
358
359			if (IsDigit(*name) && strlen(name) == IRC_MAXSID)
360	michael	1397	return hash_find_id(name);
361	adx	30
362	michael	3242	if ((client_p = clientTable[hashv]))
363	adx	30	{
364			if ((!IsServer(client_p) && !IsMe(client_p)) \|\|
365			irccmp(name, client_p->name))
366			{
367			struct Client *prev;
368
369	michael	3242	while (prev = client_p, (client_p = client_p->hnext))
370	adx	30	{
371			if ((IsServer(client_p) \|\| IsMe(client_p)) &&
372			!irccmp(name, client_p->name))
373			{
374			prev->hnext = client_p->hnext;
375			client_p->hnext = clientTable[hashv];
376			clientTable[hashv] = client_p;
377			break;
378			}
379			}
380			}
381			}
382
383	michael	1118	return client_p;
384	adx	30	}
385
386			/* hash_find_channel()
387			*
388			* inputs - pointer to name
389			* output - NONE
390	michael	2916	* side effects - New semantics: finds a channel whose name is 'name',
391	adx	30	* if can't find one returns NULL, if can find it moves
392			* it to the top of the list and returns it.
393			*/
394			struct Channel *
395			hash_find_channel(const char *name)
396			{
397	michael	4977	const unsigned int hashv = strhash(name);
398	adx	30	struct Channel *chptr = NULL;
399
400	michael	3242	if ((chptr = channelTable[hashv]))
401	adx	30	{
402	michael	4618	if (irccmp(name, chptr->name))
403	adx	30	{
404			struct Channel *prev;
405
406	michael	3242	while (prev = chptr, (chptr = chptr->hnextch))
407	adx	30	{
408	michael	4618	if (!irccmp(name, chptr->name))
409	adx	30	{
410			prev->hnextch = chptr->hnextch;
411			chptr->hnextch = channelTable[hashv];
412			channelTable[hashv] = chptr;
413			break;
414			}
415			}
416			}
417			}
418
419			return chptr;
420			}
421
422	michael	6393	struct UserHost *
423			hash_find_userhost(const char *host)
424			{
425			const unsigned int hashv = strhash(host);
426			struct UserHost *userhost;
427
428			if ((userhost = userhostTable[hashv]))
429			{
430			if (irccmp(host, userhost->host))
431			{
432			struct UserHost *prev;
433
434			while (prev = userhost, (userhost = userhost->next))
435			{
436			if (!irccmp(host, userhost->host))
437			{
438			prev->next = userhost->next;
439			userhost->next = userhostTable[hashv];
440			userhostTable[hashv] = userhost;
441			break;
442			}
443			}
444			}
445			}
446
447			return userhost;
448			}
449
450	adx	30	/* hash_get_bucket(int type, unsigned int hashv)
451			*
452			* inputs - hash value (must be between 0 and HASHSIZE - 1)
453			* output - NONE
454			* returns - pointer to first channel in channelTable[hashv]
455			* if that exists;
456			* NULL if there is no channel in that place;
457			* NULL if hashv is an invalid number.
458			* side effects - NONE
459			*/
460			void *
461			hash_get_bucket(int type, unsigned int hashv)
462			{
463			assert(hashv < HASHSIZE);
464	michael	4977
465	adx	30	if (hashv >= HASHSIZE)
466	michael	6393	return NULL;
467	adx	30
468			switch (type)
469			{
470			case HASH_TYPE_ID:
471			return idTable[hashv];
472			break;
473			case HASH_TYPE_CHANNEL:
474			return channelTable[hashv];
475			break;
476			case HASH_TYPE_CLIENT:
477			return clientTable[hashv];
478			break;
479			case HASH_TYPE_USERHOST:
480			return userhostTable[hashv];
481			break;
482			default:
483			assert(0);
484			}
485
486			return NULL;
487			}
488
489			/*
490			* Safe list code.
491			*
492			* The idea is really quite simple. As the link lists pointed to in
493			* each "bucket" of the channel hash table are traversed atomically
494			* there is no locking needed. Overall, yes, inconsistent reported
495			* state can still happen, but normally this isn't a big deal.
496			* I don't like sticking the code into hash.c but oh well. Moreover,
497			* if a hash isn't used in future, oops.
498			*
499			* - Dianora
500			*/
501
502			/* exceeding_sendq()
503			*
504			* inputs - pointer to client to check
505			* output - 1 if client is in danger of blowing its sendq
506			* 0 if it is not.
507			* side effects -
508			*
509			* Sendq limit is fairly conservative at 1/2 (In original anyway)
510			*/
511			static int
512	michael	2757	exceeding_sendq(const struct Client *to)
513	adx	30	{
514	michael	4588	if (dbuf_length(&to->connection->buf_sendq) > (get_sendq(&to->connection->confs) / 2))
515	adx	30	return 1;
516			else
517			return 0;
518			}
519
520			void
521	michael	3289	free_list_task(struct Client *source_p)
522	adx	30	{
523	michael	4870	struct ListTask *const lt = source_p->connection->list_task;
524	michael	4815	dlink_node node = NULL, node_next = NULL;
525	adx	30
526	michael	6385	dlinkDelete(&lt->node, &listing_client_list);
527	adx	30
528	michael	4815	DLINK_FOREACH_SAFE(node, node_next, lt->show_mask.head)
529	adx	30	{
530	michael	7032	xfree(node->data);
531	michael	4815	free_dlink_node(node);
532	adx	30	}
533
534	michael	4815	DLINK_FOREACH_SAFE(node, node_next, lt->hide_mask.head)
535	adx	30	{
536	michael	7032	xfree(node->data);
537	michael	4815	free_dlink_node(node);
538	adx	30	}
539
540	michael	7032	xfree(lt);
541	michael	4868	source_p->connection->list_task = NULL;
542	adx	30	}
543
544			/* list_allow_channel()
545			*
546			* inputs - channel name
547			* - pointer to a list task
548			* output - 1 if the channel is to be displayed
549			* 0 otherwise
550			* side effects -
551			*/
552			static int
553	michael	4618	list_allow_channel(const char name, const struct ListTask lt)
554	adx	30	{
555	michael	4815	const dlink_node *node = NULL;
556	adx	30
557	michael	4815	DLINK_FOREACH(node, lt->show_mask.head)
558			if (match(node->data, name) != 0)
559	adx	30	return 0;
560
561	michael	4815	DLINK_FOREACH(node, lt->hide_mask.head)
562			if (match(node->data, name) == 0)
563	adx	30	return 0;
564
565			return 1;
566			}
567
568			/* list_one_channel()
569			*
570			* inputs - client pointer to return result to
571			* - pointer to channel to list
572			* - pointer to ListTask structure
573			* output - none
574			* side effects -
575			*/
576			static void
577	michael	3288	list_one_channel(struct Client source_p, struct Channel chptr)
578	adx	30	{
579	michael	4870	const struct ListTask *const lt = source_p->connection->list_task;
580	michael	2616	char listbuf[MODEBUFLEN] = "";
581			char modebuf[MODEBUFLEN] = "";
582			char parabuf[MODEBUFLEN] = "";
583
584	michael	2495	if (SecretChannel(chptr) &&
585	michael	3428	!(HasUMode(source_p, UMODE_ADMIN) \|\| IsMember(source_p, chptr)))
586	adx	30	return;
587	michael	4890
588	michael	3288	if (dlink_list_length(&chptr->members) < lt->users_min \|\|
589			dlink_list_length(&chptr->members) > lt->users_max \|\|
590	michael	4818	(chptr->creationtime != 0 &&
591			((unsigned int)chptr->creationtime < lt->created_min \|\|
592			(unsigned int)chptr->creationtime > lt->created_max)) \|\|
593	michael	3288	(unsigned int)chptr->topic_time < lt->topicts_min \|\|
594	adx	30	(chptr->topic_time ? (unsigned int)chptr->topic_time : UINT_MAX) >
595	michael	3288	lt->topicts_max)
596	adx	30	return;
597
598	michael	4489	if (lt->topic[0] && match(lt->topic, chptr->topic))
599			return;
600
601	michael	4618	if (!list_allow_channel(chptr->name, lt))
602	adx	30	return;
603	michael	2616
604	michael	4486	channel_modes(chptr, source_p, modebuf, parabuf);
605	michael	2616
606	michael	4486	if (chptr->topic[0])
607			snprintf(listbuf, sizeof(listbuf), "[%s] ", modebuf);
608			else
609			snprintf(listbuf, sizeof(listbuf), "[%s]", modebuf);
610	michael	2616
611	michael	4618	sendto_one_numeric(source_p, &me, RPL_LIST, chptr->name,
612	michael	3109	dlink_list_length(&chptr->members),
613			listbuf, chptr->topic);
614	adx	30	}
615
616			/* safe_list_channels()
617			*
618			* inputs - pointer to client requesting list
619			* output - 0/1
620			* side effects - safely list all channels to source_p
621			*
622			* Walk the channel buckets, ensure all pointers in a bucket are
623			* traversed before blocking on a sendq. This means, no locking is needed.
624			*
625			* - Dianora
626			*/
627			void
628	michael	3288	safe_list_channels(struct Client *source_p, int only_unmasked_channels)
629	adx	30	{
630	michael	4870	struct ListTask *const lt = source_p->connection->list_task;
631	adx	30	struct Channel *chptr = NULL;
632
633			if (!only_unmasked_channels)
634			{
635	michael	3288	for (unsigned int i = lt->hash_index; i < HASHSIZE; ++i)
636	adx	30	{
637	michael	3291	if (exceeding_sendq(source_p))
638	adx	30	{
639	michael	3288	lt->hash_index = i;
640			return; /* Still more to do */
641	adx	30	}
642
643			for (chptr = channelTable[i]; chptr; chptr = chptr->hnextch)
644	michael	3288	list_one_channel(source_p, chptr);
645	adx	30	}
646			}
647			else
648			{
649	michael	4815	dlink_node *node = NULL;
650	adx	30
651	michael	4815	DLINK_FOREACH(node, lt->show_mask.head)
652			if ((chptr = hash_find_channel(node->data)))
653	michael	3288	list_one_channel(source_p, chptr);
654	adx	30	}
655
656	michael	3289	free_list_task(source_p);
657	michael	3109	sendto_one_numeric(source_p, &me, RPL_LISTEND);
658	adx	30	}