/*
 * 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 (c) 1999 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <strings.h>

#include "prtable.h"
#include "prutil.h"
#include "prfile.h"

#define FDS_TABLE_SIZE  1024

static fd_t *fd_tbl = NULL;
static int fd_max;
static int fd_cnt;
static int fd_cnt_cur;
static int fd_cnt_old;
static fds_t *fds_tbl[FDS_TABLE_SIZE];

void
fd_init(int n)
{
        fd_max = n;
        fd_cnt = fd_cnt_cur = fd_cnt_old = 0;
        fd_tbl = Zalloc(sizeof (fd_t) * n);
        (void) memset(fds_tbl, 0, sizeof (fds_t *) * FDS_TABLE_SIZE);
}

void
fd_exit()
{
        if (fd_tbl)
                free(fd_tbl);
}

void
fd_close(fd_t *fdp)
{
        if (fdp) {
                if (fdp->fd_fd >= 0 && fdp->fd_name[0] != '\0') {
                        (void) close(fdp->fd_fd);
                        fd_cnt--;
                }

                (void) memset(fdp, 0, sizeof (fd_t));
                fdp->fd_fd = -1;
        }
}

void
fd_closeall()
{
        fd_t *fdp = fd_tbl;
        int i;

        for (i = 0; i < fd_max; i++) {
                fd_close(fdp);
                fdp++;
        }
}

static void
fd_recycle()
{
        fd_t *fdp = fd_tbl;
        int counter;
        int i;

        counter = abs(fd_cnt_old - fd_cnt) + NUM_RESERVED_FD;

        for (i = 0; i < fd_max; i++, fdp++) {

                if (fdp->fd_fd == -1)
                        continue;       /* skip recycled ones */

                if (fdp->fd_name[0] != '\0') {  /* file has name */
                        (void) close(fdp->fd_fd);
                        fd_cnt--;
                        counter--;
                        fdp->fd_fd = -1;
                }

                if (counter == 0)
                        break;
        }
}

fd_t *
fd_open(char *name, int flags, fd_t *fdp)
{
        fd_t *fdp_new;
        int fd;

        if (fd_cnt > fd_max - NUM_RESERVED_FD)
                fd_recycle();

        if (fdp != NULL) {
                if ((strcmp(fdp->fd_name, name) == 0) && (fdp->fd_fd >= 0)) {
                        fd_cnt_cur++;
                        return (fdp);
                }
        }

again:  fd = open(name, flags);

        if (fd == -1) {
                if ((errno == EMFILE) || (errno == ENFILE)) {
                        fd_recycle();
                        goto again;
                }
                fdp_new = NULL;
        } else {
                fdp_new = &fd_tbl[fd];
                fdp_new->fd_fd = fd;
                fdp_new->fd_flags = flags;
                (void) strcpy(fdp_new->fd_name, name);
                fd_cnt++;
                fd_cnt_cur++;
        }
        return (fdp_new);
}

int
fd_getfd(fd_t *fdp)
{
        return (fdp->fd_fd);
}

void
fd_update()
{
        fd_cnt_old = fd_cnt_cur;
        fd_cnt_cur = 0;
}

fds_t *
fds_get(pid_t pid)
{
        fds_t *fdsp;
        int hash = pid % FDS_TABLE_SIZE;

        for (fdsp = fds_tbl[hash]; fdsp; fdsp = fdsp->fds_next)
                if (fdsp->fds_pid == pid)       /* searching for pid */
                        return (fdsp);

        fdsp = Zalloc(sizeof (fds_t));  /* adding new if pid was not found */
        fdsp->fds_pid = pid;
        fdsp->fds_next = fds_tbl[hash];
        fds_tbl[hash] = fdsp;
        return (fdsp);
}

void
fds_rm(pid_t pid)
{
        fds_t *fds;
        fds_t *fds_prev = NULL;
        int hash = pid % FDS_TABLE_SIZE;

        for (fds = fds_tbl[hash]; fds && fds->fds_pid != pid;
            fds = fds->fds_next)        /* finding pid */
                fds_prev = fds;

        if (fds) {                      /* if pid was found */

                fd_close(fds->fds_psinfo);
                fd_close(fds->fds_usage);
                fd_close(fds->fds_lpsinfo);
                fd_close(fds->fds_lusage);

                if (fds_prev)
                        fds_prev->fds_next = fds->fds_next;
                else
                        fds_tbl[hash] = fds->fds_next;

                free(fds);
        }
}