sys/common/fdlist.c

	fdlist.c revision 5d54f3d8999eac1762fe0a8c7177d20f1f201fae
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 1990 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <stdio.h>

#define NUM_FD  16

struct fd_lst {
        int     fd[NUM_FD];                 /* list of 16 descriptors */
    int     fds[NUM_FD];
        struct fd_lst *next;
};


static struct fd_lst *fdlist = NULL;
static struct fd_lst *fdtail = NULL;

void
fd_init(struct fd_lst *lst)
{
    int i;

    for (i=0; i<NUM_FD; i++) {
        lst->fd[i] = -1;
        lst->fds[i] = -1;
    }
    lst->next = NULL;
}


int
fd_add(int fd, int fds)
{
    int i;
    struct fd_lst *fdc, *fdnew;

    fdc = fdlist;

    while (fdc != NULL) {
        for (i=0; i<NUM_FD; i++) {
            if (fdc->fd[i] == -1) {
                fdc->fd[i] = fd;
                fdc->fds[i] = fds;
                return(0);
            }
        }
        fdc = fdc->next;
    }

    if ((fdnew = (struct fd_lst *)malloc(sizeof(struct fd_lst))) == NULL) {
        fprintf(stderr,"fd_add: malloc failed\n");
        exit(1);
    }

    fd_init(fdnew);

    if (fdlist == NULL)
        fdlist = fdnew;
    else
        fdtail->next = fdnew;

    fdtail = fdnew;
    fdtail->fd[0] = fd;
    fdtail->fds[0] = fds;
    return (0);
}


int
fd_rem(int fd)
{
    int i;
    struct fd_lst *fdc = fdlist;

    while (fdc != NULL) {
        for (i=0; i<NUM_FD; i++) {
            if (fdc->fd[i] == fd) {
                fdc->fd[i] = -1;
                fdc->fds[i] = -1;
                return (0);
            }
        }
        fdc = fdc->next;
    }
    return (0);
}


int
fd_get(int fd)
{
    int i;
    struct fd_lst *fdc = fdlist;

    while (fdc != NULL) {
        for (i=0; i<NUM_FD; i++) {
            if (fdc->fd[i] == fd) {
                return (fdc->fds[i]);
            }
        }
        fdc = fdc->next;
    }
    return (-1);
}