/*
 * 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) 1995-1997, by Sun Microsystems, Inc.
 * All rights reserved.
 */

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


/*      Portions Copyright(c) 1988, Sun Microsystems Inc.       */
/*      All Rights Reserved                                     */

/*LINTLIBRARY*/

/*
 * Compatibility lib for SunOS's wait4().
 */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/times.h>
#include <sys/wait.h>
#include <sys/siginfo.h>
#include <sys/procset.h>
#include <sys/param.h>
#include <sys/resource.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

/*
 * Since sysV does not support rusage as in BSD, an approximate approach
 * is:
 *      ...
 *      call times
 *      call waitid
 *      if ( a child is found )
 *              call times again
 *              rusage ~= diff in the 2 times call
 *      ...
 */

/*
 * forward declaration
 */
static int wstat(int, int);

pid_t
wait4(pid_t pid, int *status, int options, struct rusage *rp)
{
        struct  tms     before_tms;
        struct  tms     after_tms;
        siginfo_t       info;
        int             error;
        int             noptions;
        idtype_t        idtype;

        if ((long)status == -1L || (long)rp == -1L) {
                errno = EFAULT;
                return (-1);
        }

        if (rp)
                (void) memset(rp, 0, sizeof (struct rusage));
        (void) memset(&info, 0, sizeof (siginfo_t));
        if (times(&before_tms) < 0)
                return (-1);    /* errno is set by times() */

        /*
         * SunOS's wait4() only supports WNOHANG & WUNTRACED
         */
        if (options & ~(WNOHANG|WUNTRACED))
                return (EINVAL);        /* used to be done by the kernel */
        noptions = options | WEXITED | WTRAPPED;

        /*
         * Emulate undocumented 4.x semantics for 1186845
         */
        if (pid < 0) {
                pid = -pid;
                idtype = P_PGID;
        } else if (pid == 0)
                idtype = P_ALL;
        else
                idtype = P_PID;

        error = waitid(idtype, pid, &info, noptions);
        if (error == 0) {
                clock_t diffu;  /* difference in usertime (ticks) */
                clock_t diffs;  /* difference in systemtime (ticks) */

                if ((options & WNOHANG) && (info.si_pid == 0))
                        return (0);     /* no child found */

                if (rp) {
                        if (times(&after_tms) < 0)
                                return (-1);    /* errno set by times() */
                        /*
                         * The system/user time is an approximation only !!!
                         */
                        diffu = after_tms.tms_cutime - before_tms.tms_cutime;
                        diffs = after_tms.tms_cstime - before_tms.tms_cstime;
                        rp->ru_utime.tv_sec = diffu / HZ;
                        rp->ru_utime.tv_usec = (diffu % HZ) * (1000000 / HZ);
                        rp->ru_stime.tv_sec = diffs/ HZ;
                        rp->ru_stime.tv_usec = (diffs % HZ) * (1000000 / HZ);
                }
                if (status)
                        *status = wstat(info.si_code, info.si_status);
                return (info.si_pid);
        } else {
                return (-1);            /* error number is set by waitid() */
        }
}

/*
 * Convert the status code to old style wait status
 */
static int
wstat(int code, int status)
{
        int stat = (status & 0377);

        switch (code) {
        case CLD_EXITED:
                stat <<= 8;
                break;
        case CLD_DUMPED:
                stat |= WCOREFLG;
                break;
        case CLD_KILLED:
                break;
        case CLD_TRAPPED:
        case CLD_STOPPED:
                stat <<= 8;
                stat |= WSTOPFLG;
                break;
        case CLD_CONTINUED:
                stat = WCONTFLG;
                break;
        }
        return (stat);
}