usr/src/sys/kern/kern_exit.c

/*
 * Copyright (c) 1982, 1986, 1989, 1991 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)kern_exit.c 7.35 (Berkeley) 6/27/91
 */

#include "param.h"
#include "systm.h"
#include "map.h"
#include "ioctl.h"
#include "tty.h"
#include "time.h"
#include "resource.h"
#include "kernel.h"
#include "proc.h"
#include "buf.h"
#include "wait.h"
#include "file.h"
#include "vnode.h"
#include "syslog.h"
#include "malloc.h"
#include "resourcevar.h"

#include "machine/cpu.h"
#ifdef COMPAT_43
#include "machine/reg.h"
#include "machine/psl.h"
#endif

#include "vm/vm.h"
#include "vm/vm_kern.h"

/*
 * Exit system call: pass back caller's arg
 */
/* ARGSUSED */
rexit(p, uap, retval)
        struct proc *p;
        struct args {
                int     rval;
        } *uap;
        int *retval;
{

        exit(p, W_EXITCODE(uap->rval, 0));
        /* NOTREACHED */
}

/*
 * Exit: deallocate address space and other resources,
 * change proc state to zombie, and unlink proc from allproc
 * and parent's lists.  Save exit status and rusage for wait().
 * Check for child processes and orphan them.
 */
exit(p, rv)
        register struct proc *p;
        int rv;
{
        register struct proc *q, *nq;
        register struct proc **pp;
        int s;

#ifdef PGINPROF
        vmsizmon();
#endif
        MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage),
                M_ZOMBIE, M_WAITOK);
        /*
         * If parent is waiting for us to exit or exec,
         * SPPWAIT is set; we will wakeup the parent below.
         */
        p->p_flag &= ~(STRC|SPPWAIT);
        p->p_flag |= SWEXIT;
        p->p_sigignore = ~0;
        p->p_sig = 0;
        untimeout(realitexpire, (caddr_t)p);

        /*
         * Close open files and release open-file table.
         * This may block!
         */
        fdfree(p);

        /* The next two chunks should probably be moved to vmspace_exit. */
#ifdef SYSVSHM
        if (p->p_vmspace->vm_shm)
                shmexit(p);
#endif
        /*
         * Release user portion of address space.
         * This releases references to vnodes,
         * which could cause I/O if the file has been unlinked.
         * Need to do this early enough that we can still sleep.
         * Can't free the entire vmspace as the kernel stack
         * may be mapped within that space also.
         */
        if (p->p_vmspace->vm_refcnt == 1)
                (void) vm_map_remove(&p->p_vmspace->vm_map, VM_MIN_ADDRESS,
                    VM_MAXUSER_ADDRESS);

        if (p->p_pid == 1)
                panic("init died");
        if (SESS_LEADER(p)) {
                register struct session *sp = p->p_session;

                if (sp->s_ttyvp) {
                        /*
                         * Controlling process.
                         * Signal foreground pgrp,
                         * drain controlling terminal
                         * and revoke access to controlling terminal.
                         */
                        if (sp->s_ttyp->t_session == sp) {
                                if (sp->s_ttyp->t_pgrp)
                                        pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
                                (void) ttywait(sp->s_ttyp);
                                vgoneall(sp->s_ttyvp);
                        }
                        vrele(sp->s_ttyvp);
                        sp->s_ttyvp = NULL;
                        /*
                         * s_ttyp is not zero'd; we use this to indicate
                         * that the session once had a controlling terminal.
                         * (for logging and informational purposes)
                         */
                }
                sp->s_leader = NULL;
        }
        fixjobc(p, p->p_pgrp, 0);
        p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
        (void) acct(p);
        if (--p->p_limit->p_refcnt == 0)
                FREE(p->p_limit, M_SUBPROC);
#ifdef KTRACE
        /*
         * release trace file
         */
        if (p->p_tracep)
                vrele(p->p_tracep);
#endif

        /*
         * Remove proc from allproc queue and pidhash chain.
         * Place onto zombproc.  Unlink from parent's child list.
         */
        if (*p->p_prev = p->p_nxt)
                p->p_nxt->p_prev = p->p_prev;
        if (p->p_nxt = zombproc)
                p->p_nxt->p_prev = &p->p_nxt;
        p->p_prev = &zombproc;
        zombproc = p;
        p->p_stat = SZOMB;
        curproc = NULL;
        for (pp = &pidhash[PIDHASH(p->p_pid)]; *pp; pp = &(*pp)->p_hash)
                if (*pp == p) {
                        *pp = p->p_hash;
                        goto done;
                }
        panic("exit");
done:

        if (p->p_cptr)          /* only need this if any child is S_ZOMB */
                wakeup((caddr_t) initproc);
        for (q = p->p_cptr; q != NULL; q = nq) {
                nq = q->p_osptr;
                if (nq != NULL)
                        nq->p_ysptr = NULL;
                if (initproc->p_cptr)
                        initproc->p_cptr->p_ysptr = q;
                q->p_osptr = initproc->p_cptr;
                q->p_ysptr = NULL;
                initproc->p_cptr = q;

                q->p_pptr = initproc;
                /*
                 * Traced processes are killed
                 * since their existence means someone is screwing up.
                 */
                if (q->p_flag&STRC) {
                        q->p_flag &= ~STRC;
                        psignal(q, SIGKILL);
                }
        }
        p->p_cptr = NULL;

        /*
         * Save exit status and final rusage info,
         * adding in child rusage info and self times.
         */
        p->p_xstat = rv;
        *p->p_ru = p->p_stats->p_ru;
        p->p_ru->ru_stime = p->p_stime;
        p->p_ru->ru_utime = p->p_utime;
        ruadd(p->p_ru, &p->p_stats->p_cru);

        /*
         * Notify parent that we're gone.
         */
        psignal(p->p_pptr, SIGCHLD);
        wakeup((caddr_t)p->p_pptr);
#if defined(tahoe)
        /* move this to cpu_exit */
        p->p_addr->u_pcb.pcb_savacc.faddr = (float *)NULL;
#endif
        /*
         * Finally, call machine-dependent code to release the remaining
         * resources including address space, the kernel stack and pcb.
         * The address space is released by "vmspace_free(p->p_vmspace)";
         * This is machine-dependent, as we may have to change stacks
         * or ensure that the current one isn't reallocated before we
         * finish.  cpu_exit will end with a call to swtch(), finishing
         * our execution (pun intended).
         */
        cpu_exit(p);
        /* NOTREACHED */
}

#ifdef COMPAT_43
owait(p, uap, retval)
        struct proc *p;
        register struct args {
                int     pid;
                int     *status;
                int     options;
                struct  rusage *rusage;
                int     compat;
        } *uap;
        int *retval;
{

        if ((p->p_regs[PS] & PSL_ALLCC) != PSL_ALLCC) {
                uap->options = 0;
                uap->rusage = 0;
        } else {
                uap->options = p->p_regs[R0];
                uap->rusage = (struct rusage *)p->p_regs[R1];
        }
        uap->pid = WAIT_ANY;
        uap->status = 0;
        uap->compat = 1;
        return (wait1(p, uap, retval));
}

wait4(p, uap, retval)
        struct proc *p;
        struct args {
                int     pid;
                int     *status;
                int     options;
                struct  rusage *rusage;
                int     compat;
        } *uap;
        int *retval;
{

        uap->compat = 0;
        return (wait1(p, uap, retval));
}
#else
#define wait1   wait4
#endif

/*
 * Wait: check child processes to see if any have exited,
 * stopped under trace, or (optionally) stopped by a signal.
 * Pass back status and deallocate exited child's proc structure.
 */
wait1(q, uap, retval)
        register struct proc *q;
        register struct args {
                int     pid;
                int     *status;
                int     options;
                struct  rusage *rusage;
#ifdef COMPAT_43
                int compat;
#endif
        } *uap;
        int retval[];
{
        register int nfound;
        register struct proc *p;
        int status, error;

        if (uap->pid == 0)
                uap->pid = -q->p_pgid;
#ifdef notyet
        if (uap->options &~ (WUNTRACED|WNOHANG))
                return (EINVAL);
#endif
loop:
        nfound = 0;
        for (p = q->p_cptr; p; p = p->p_osptr) {
                if (uap->pid != WAIT_ANY &&
                    p->p_pid != uap->pid && p->p_pgid != -uap->pid)
                        continue;
                nfound++;
                if (p->p_stat == SZOMB) {
                        retval[0] = p->p_pid;
#ifdef COMPAT_43
                        if (uap->compat)
                                retval[1] = p->p_xstat;
                        else
#endif
                        if (uap->status) {
                                status = p->p_xstat;    /* convert to int */
                                if (error = copyout((caddr_t)&status,
                                    (caddr_t)uap->status, sizeof(status)))
                                        return (error);
                        }
                        if (uap->rusage && (error = copyout((caddr_t)p->p_ru,
                            (caddr_t)uap->rusage, sizeof (struct rusage))))
                                return (error);
                        p->p_xstat = 0;
                        ruadd(&q->p_stats->p_cru, p->p_ru);
                        FREE(p->p_ru, M_ZOMBIE);
                        if (--p->p_cred->p_refcnt == 0) {
                                crfree(p->p_cred->pc_ucred);
                                FREE(p->p_cred, M_SUBPROC);
                        }

                        /*
                         * Finally finished with old proc entry.
                         * Unlink it from its process group and free it.
                         */
                        leavepgrp(p);
                        if (*p->p_prev = p->p_nxt)      /* off zombproc */
                                p->p_nxt->p_prev = p->p_prev;
                        if (q = p->p_ysptr)
                                q->p_osptr = p->p_osptr;
                        if (q = p->p_osptr)
                                q->p_ysptr = p->p_ysptr;
                        if ((q = p->p_pptr)->p_cptr == p)
                                q->p_cptr = p->p_osptr;

                        /*
                         * Give machine-dependent layer a chance
                         * to free anything that cpu_exit couldn't
                         * release while still running in process context.
                         */
                        cpu_wait(p);
                        FREE(p, M_PROC);
                        nprocs--;
                        return (0);
                }
                if (p->p_stat == SSTOP && (p->p_flag & SWTED) == 0 &&
                    (p->p_flag & STRC || uap->options & WUNTRACED)) {
                        p->p_flag |= SWTED;
                        retval[0] = p->p_pid;
#ifdef COMPAT_43
                        if (uap->compat) {
                                retval[1] = W_STOPCODE(p->p_xstat);
                                error = 0;
                        } else
#endif
                        if (uap->status) {
                                status = W_STOPCODE(p->p_xstat);
                                error = copyout((caddr_t)&status,
                                    (caddr_t)uap->status, sizeof(status));
                        } else
                                error = 0;
                        return (error);
                }
        }
        if (nfound == 0)
                return (ECHILD);
        if (uap->options & WNOHANG) {
                retval[0] = 0;
                return (0);
        }
        if (error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0))
                return (error);
        goto loop;
}