port/gen/setpriority.c

/*
 * 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.
 */

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

#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);
}