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/*
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 * Copyright (c) 2005-2006, Kohsuke Ohtani
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the author nor the names of any co-contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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/*
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 * hash.c - pid/pgid mapping tables.
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 */
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#include <sys/prex.h>
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#include <ipc/ipc.h>
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#include <sys/list.h>
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#include <unistd.h>
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#include "proc.h"
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/*
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 * Hash tables for ID mapping
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 */
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static struct list pid_table[ID_MAXBUCKETS];        /* mapping: pid  -> proc */
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static struct list task_table[ID_MAXBUCKETS];        /* mapping: task -> proc */
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static struct list pgid_table[ID_MAXBUCKETS];        /* mapping: pgid -> pgrp */
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/*
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 * Locate a process by number
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 */
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struct proc *
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p_find(pid_t pid)
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{
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        list_t head, n;
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        struct proc *p = NULL;
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        head = &pid_table[IDHASH(pid)];
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        n = list_first(head);
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        while (n != head) {
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                p = list_entry(n, struct proc, p_pid_link);
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                if (p->p_pid == pid)
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                        return p;
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                n = list_next(n);
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        }
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        return NULL;
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}
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/*
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 * Locate a process group by number
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 */
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struct pgrp *
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pg_find(pid_t pgid)
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{
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        list_t head, n;
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        struct pgrp *g = NULL;
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        head = &pgid_table[IDHASH(pgid)];
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        n = list_first(head);
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        while (n != head) {
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                g = list_entry(n, struct pgrp, pg_link);
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                if (g->pg_pgid == pgid)
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                        return g;
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                n = list_next(n);
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        }
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        return NULL;
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}
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/*
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 * Find process by task ID.
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 */
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struct proc *
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task_to_proc(task_t task)
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{
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        list_t head, n;
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        struct proc *p = NULL;
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        head = &task_table[IDHASH(task)];
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        n = list_first(head);
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        while (n != head) {
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                p = list_entry(n, struct proc, p_task_link);
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                if (p->p_task == task)
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                        return p;
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                n = list_next(n);
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        }
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        return NULL;
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}
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/*
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 * Add process to the pid table and the task table.
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 * This routine assumes pid and task data has been already initialized.
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 */
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void
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p_add(struct proc *p)
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{
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        list_insert(&pid_table[IDHASH(p->p_pid)], &p->p_pid_link);
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        list_insert(&task_table[IDHASH(p->p_task)], &p->p_task_link);
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}
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/*
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 * Remove process from both of pid table and task table.
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 */
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void
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p_remove(struct proc *p)
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{
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        list_remove(&p->p_pid_link);
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        list_remove(&p->p_task_link);
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}
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/*
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 * Add process group to table.
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 * This routine assumes pgid has been already initialized.
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 */
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void
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pg_add(struct pgrp *pgrp)
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{
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        list_insert(&pgid_table[IDHASH(pgrp->pg_pgid)], &pgrp->pg_link);
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}
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/*
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 * Remove process from pgid table.
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 */
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void
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pg_remove(struct pgrp *pgrp)
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{
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        list_remove(&pgrp->pg_link);
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}
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/*
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 * Initialize tables.
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 */
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void
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table_init(void)
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{
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        int i;
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        for (i = 0; i < ID_MAXBUCKETS; i++) {
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                list_init(&pid_table[i]);
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                list_init(&task_table[i]);
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                list_init(&pgid_table[i]);
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        }
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}