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Annotation of prex-old/usr/server/proc/hash.c, Revision 1.1

1.1     ! nbrk        1: /*
        !             2:  * Copyright (c) 2005-2006, Kohsuke Ohtani
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms, with or without
        !             6:  * modification, are permitted provided that the following conditions
        !             7:  * are met:
        !             8:  * 1. Redistributions of source code must retain the above copyright
        !             9:  *    notice, this list of conditions and the following disclaimer.
        !            10:  * 2. Redistributions in binary form must reproduce the above copyright
        !            11:  *    notice, this list of conditions and the following disclaimer in the
        !            12:  *    documentation and/or other materials provided with the distribution.
        !            13:  * 3. Neither the name of the author nor the names of any co-contributors
        !            14:  *    may be used to endorse or promote products derived from this software
        !            15:  *    without specific prior written permission.
        !            16:  *
        !            17:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
        !            18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
        !            21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            27:  * SUCH DAMAGE.
        !            28:  */
        !            29:
        !            30: /*
        !            31:  * hash.c - pid/pgid mapping tables.
        !            32:  */
        !            33:
        !            34: #include <server/stdmsg.h>
        !            35: #include <sys/list.h>
        !            36: #include <unistd.h>
        !            37:
        !            38: #include "proc.h"
        !            39:
        !            40: /*
        !            41:  * Hash tables for ID mapping
        !            42:  */
        !            43: static struct list pid_hash[ID_MAXBUCKETS];    /* mapping: pid  -> proc */
        !            44: static struct list task_hash[ID_MAXBUCKETS];   /* mapping: task -> proc */
        !            45: static struct list pgid_hash[ID_MAXBUCKETS];   /* mapping: pgid -> pgrp */
        !            46:
        !            47: /*
        !            48:  * Find process by pid.
        !            49:  */
        !            50: struct proc *
        !            51: proc_find(pid_t pid)
        !            52: {
        !            53:        list_t head, n;
        !            54:        struct proc *p = NULL;
        !            55:
        !            56:        head = &pid_hash[IDHASH(pid)];
        !            57:        n = list_first(head);
        !            58:        while (n != head) {
        !            59:                p = list_entry(n, struct proc, pid_link);
        !            60:                if (p->pid == pid)
        !            61:                        return p;
        !            62:                n = list_next(n);
        !            63:        }
        !            64:        return NULL;
        !            65: }
        !            66:
        !            67: /*
        !            68:  * Find process group by pgid.
        !            69:  */
        !            70: struct pgrp *
        !            71: pgrp_find(pid_t pgid)
        !            72: {
        !            73:        list_t head, n;
        !            74:        struct pgrp *g = NULL;
        !            75:
        !            76:        head = &pgid_hash[IDHASH(pgid)];
        !            77:        n = list_first(head);
        !            78:        while (n != head) {
        !            79:                g = list_entry(n, struct pgrp, pgid_link);
        !            80:                if (g->pgid == pgid)
        !            81:                        return g;
        !            82:                n = list_next(n);
        !            83:        }
        !            84:        return NULL;
        !            85: }
        !            86:
        !            87: /*
        !            88:  * Find process by task ID.
        !            89:  */
        !            90: struct proc *
        !            91: task_to_proc(task_t task)
        !            92: {
        !            93:        list_t head, n;
        !            94:        struct proc *p = NULL;
        !            95:
        !            96:        head = &task_hash[IDHASH(task)];
        !            97:        n = list_first(head);
        !            98:        while (n != head) {
        !            99:                p = list_entry(n, struct proc, task_link);
        !           100:                if (p->task == task)
        !           101:                        return p;
        !           102:                n = list_next(n);
        !           103:        }
        !           104:        return NULL;
        !           105: }
        !           106:
        !           107: /*
        !           108:  * Add process to the pid table and the task table.
        !           109:  * This routine assumes pid and task data has been already initialized.
        !           110:  */
        !           111: void
        !           112: proc_add(struct proc *proc)
        !           113: {
        !           114:
        !           115:        list_insert(&pid_hash[IDHASH(proc->pid)], &proc->pid_link);
        !           116:        list_insert(&task_hash[IDHASH(proc->task)], &proc->task_link);
        !           117: }
        !           118:
        !           119: /*
        !           120:  * Remove process from both of pid table and task table.
        !           121:  */
        !           122: void
        !           123: proc_remove(struct proc *proc)
        !           124: {
        !           125:
        !           126:        list_remove(&proc->pid_link);
        !           127:        list_remove(&proc->task_link);
        !           128: }
        !           129:
        !           130: /*
        !           131:  * Add process group to table.
        !           132:  * This routine assumes pgid has been already initialized.
        !           133:  */
        !           134: void
        !           135: pgrp_add(struct pgrp *pgrp)
        !           136: {
        !           137:
        !           138:        list_insert(&pgid_hash[IDHASH(pgrp->pgid)], &pgrp->pgid_link);
        !           139: }
        !           140:
        !           141: /*
        !           142:  * Remove process from pgid table.
        !           143:  */
        !           144: void
        !           145: pgrp_remove(struct pgrp *pgrp)
        !           146: {
        !           147:
        !           148:        list_remove(&pgrp->pgid_link);
        !           149: }
        !           150:
        !           151: /*
        !           152:  * Initialize tables.
        !           153:  */
        !           154: void
        !           155: table_init(void)
        !           156: {
        !           157:        int i;
        !           158:
        !           159:        for (i = 0; i < ID_MAXBUCKETS; i++) {
        !           160:                list_init(&pid_hash[i]);
        !           161:                list_init(&task_hash[i]);
        !           162:                list_init(&pgid_hash[i]);
        !           163:        }
        !           164: }