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/*

 * Copyright (c) 2005-2006, Kohsuke Ohtani

 * 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.

 * 3. Neither the name of the author nor the names of any co-contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * 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.

 */

/*

 * hash.c - pid/pgid mapping tables.

 */

#include <sys/prex.h>

#include <ipc/ipc.h>

#include <sys/list.h>

#include <unistd.h>

#include "proc.h"

/*

 * Hash tables for ID mapping

 */

static struct list pid_table[ID_MAXBUCKETS];        /* mapping: pid  -> proc */

static struct list task_table[ID_MAXBUCKETS];        /* mapping: task -> proc */

static struct list pgid_table[ID_MAXBUCKETS];        /* mapping: pgid -> pgrp */

/*

 * Locate a process by number

 */

struct proc *

p_find(pid_t pid)

{

        list_t head, n;

        struct proc *p = NULL;

        head = &pid_table[IDHASH(pid)];

        n = list_first(head);

        while (n != head) {

                p = list_entry(n, struct proc, p_pid_link);

                if (p->p_pid == pid)

                        return p;

                n = list_next(n);

        }

        return NULL;

}

/*

 * Locate a process group by number

 */

struct pgrp *

pg_find(pid_t pgid)

{

        list_t head, n;

        struct pgrp *g = NULL;

        head = &pgid_table[IDHASH(pgid)];

        n = list_first(head);

        while (n != head) {

                g = list_entry(n, struct pgrp, pg_link);

                if (g->pg_pgid == pgid)

                        return g;

                n = list_next(n);

        }

        return NULL;

}

/*

 * Find process by task ID.

 */

struct proc *

task_to_proc(task_t task)

{

        list_t head, n;

        struct proc *p = NULL;

        head = &task_table[IDHASH(task)];

        n = list_first(head);

        while (n != head) {

                p = list_entry(n, struct proc, p_task_link);

                if (p->p_task == task)

                        return p;

                n = list_next(n);

        }

        return NULL;

}

/*

 * Add process to the pid table and the task table.

 * This routine assumes pid and task data has been already initialized.

 */

void

p_add(struct proc *p)

{

        list_insert(&pid_table[IDHASH(p->p_pid)], &p->p_pid_link);

        list_insert(&task_table[IDHASH(p->p_task)], &p->p_task_link);

}

/*

 * Remove process from both of pid table and task table.

 */

void

p_remove(struct proc *p)

{

        list_remove(&p->p_pid_link);

        list_remove(&p->p_task_link);

}

/*

 * Add process group to table.

 * This routine assumes pgid has been already initialized.

 */

void

pg_add(struct pgrp *pgrp)

{

        list_insert(&pgid_table[IDHASH(pgrp->pg_pgid)], &pgrp->pg_link);

}

/*

 * Remove process from pgid table.

 */

void

pg_remove(struct pgrp *pgrp)

{

        list_remove(&pgrp->pg_link);

}

/*

 * Initialize tables.

 */

void

table_init(void)

{

        int i;

        for (i = 0; i < ID_MAXBUCKETS; i++) {

                list_init(&pid_table[i]);

                list_init(&task_table[i]);

                list_init(&pgid_table[i]);

        }

}