/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

#include "lint.h"
#include <string.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/procset.h>
#include <sys/priocntl.h>
#include <limits.h>
#include <errno.h>
#include <priv.h>

static idtype_t
prio_to_idtype(int which)
{
        switch (which) {

        case PRIO_PROCESS:
                return (P_PID);

        case PRIO_PGRP:
                return (P_PGID);

        case PRIO_USER:
                return (P_UID);

        case PRIO_GROUP:
                return (P_GID);

        case PRIO_SESSION:
                return (P_SID);

        case PRIO_LWP:
                return (P_LWPID);

        case PRIO_TASK:
                return (P_TASKID);

        case PRIO_PROJECT:
                return (P_PROJID);

        case PRIO_ZONE:
                return (P_ZONEID);

        case PRIO_CONTRACT:
                return (P_CTID);

        default:
                return (-1);
        }
}

static int
old_idtype(int which)
{
        switch (which) {
        case PRIO_PROCESS:
        case PRIO_PGRP:
        case PRIO_USER:
                return (1);
        default:
                return (0);
        }
}

int
getpriority(int which, id_t who)
{
        id_t id;
        idtype_t idtype;
        pcnice_t pcnice;

        if ((idtype = prio_to_idtype(which)) == -1) {
                errno = EINVAL;
                return (-1);
        }

        if (who < 0) {
                if (old_idtype(which)) {
                        errno = EINVAL;
                        return (-1);
                } else if (who != P_MYID) {
                        errno = EINVAL;
                        return (-1);
                }
        }

        /*
         * The POSIX standard requires that a 0 value for the who argument
         * should specify the current process, process group, or user.
         * For all other id types we can treat zero as normal id value.
         */
        if (who == 0 && old_idtype(which))
                id = P_MYID;
        else
                id = who;

        pcnice.pc_val = 0;
        pcnice.pc_op = PC_GETNICE;

        if (priocntl(idtype, id, PC_DONICE, &pcnice) == -1)
                return (-1);
        else
                return (pcnice.pc_val);
}

int
setpriority(int which, id_t who, int prio)
{
        id_t id;
        idtype_t idtype;
        pcnice_t pcnice;
        int ret;

        if ((idtype = prio_to_idtype(which)) == -1) {
                errno = EINVAL;
                return (-1);
        }

        if (who < 0) {
                if (old_idtype(which)) {
                        errno = EINVAL;
                        return (-1);
                } else if (who != P_MYID) {
                        errno = EINVAL;
                        return (-1);
                }
        }

        if (who == 0 && old_idtype(which))
                id = P_MYID;
        else
                id = who;

        if (prio > NZERO - 1)
                prio = NZERO - 1;
        else if (prio < -NZERO)
                prio = -NZERO;

        pcnice.pc_val = prio;
        pcnice.pc_op = PC_SETNICE;

        ret = priocntl(idtype, id, PC_DONICE, &pcnice);

        if (ret != 0 && errno == EPERM) {
                pcnice_t        gpcnice = { 0, PC_GETNICE };
                priv_set_t      *pset = NULL;

                /*
                 * The priocntl PC_DONICE subcommand returns EPERM if we lack
                 * sufficient privileges to carry out the operation, but
                 * setpriority(3C) may need to return EACCES.  We can't just
                 * change EPERM to EACCES, because there are other conditions
                 * which legitimately cause EPERM (such as an euid/ruid mismatch
                 * between the current process and the target.).
                 *
                 * setpriority(3C) must return EACCES if we lack the privilege
                 * checked for below and we are trying to increase the process
                 * priority (by lowering the numeric value of its priority).
                 */
                if (priocntl(idtype, id, PC_DONICE, &gpcnice) == 0 &&
                    prio < gpcnice.pc_val) {
                        if ((pset = priv_allocset()) != NULL &&
                            getppriv(PRIV_EFFECTIVE, pset) == 0 &&
                            !priv_ismember(pset, "proc_priocntl"))
                                errno = EACCES;
                        if (pset != NULL)
                                priv_freeset(pset);
                }
        }

        return (ret);
}