xnu-517.11.1.tar.gz

[apple/xnu.git] / bsd / kern / kern_proc.c

/*
 * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1982, 1986, 1989, 1991, 1993
 *      The 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_proc.c 8.4 (Berkeley) 1/4/94
 */
/* HISTORY
 *  04-Aug-97  Umesh Vaishampayan (umeshv@apple.com)
 *      Added current_proc_EXTERNAL() function for the use of kernel
 *      lodable modules.
 *
 *  05-Jun-95 Mac Gillon (mgillon) at NeXT
 *      New version based on 3.3NS and 4.4
 */


#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/acct.h>
#include <sys/wait.h>
#include <sys/file.h>
#include <ufs/ufs/quota.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/signalvar.h>
#include <sys/syslog.h>

/*
 * Structure associated with user cacheing.
 */
struct uidinfo {
        LIST_ENTRY(uidinfo) ui_hash;
        uid_t   ui_uid;
        long    ui_proccnt;
};
#define UIHASH(uid)     (&uihashtbl[(uid) & uihash])
LIST_HEAD(uihashhead, uidinfo) *uihashtbl;
u_long uihash;          /* size of hash table - 1 */

/*
 * Other process lists
 */
struct pidhashhead *pidhashtbl;
u_long pidhash;
struct pgrphashhead *pgrphashtbl;
u_long pgrphash;
struct proclist allproc;
struct proclist zombproc;

/* Name to give to core files */
__private_extern__ char corefilename[MAXPATHLEN+1] = {"/cores/core.%P"};

static void orphanpg(struct pgrp *pg);

/*
 * Initialize global process hashing structures.
 */
void
procinit()
{

        LIST_INIT(&allproc);
        LIST_INIT(&zombproc);
        pidhashtbl = hashinit(maxproc / 4, M_PROC, &pidhash);
        pgrphashtbl = hashinit(maxproc / 4, M_PROC, &pgrphash);
        uihashtbl = hashinit(maxproc / 16, M_PROC, &uihash);
}

/*
 * Change the count associated with number of processes
 * a given user is using.
 */
int
chgproccnt(uid, diff)
        uid_t   uid;
        int     diff;
{
        register struct uidinfo *uip;
        register struct uihashhead *uipp;

        uipp = UIHASH(uid);
        for (uip = uipp->lh_first; uip != 0; uip = uip->ui_hash.le_next)
                if (uip->ui_uid == uid)
                        break;
        if (uip) {
                uip->ui_proccnt += diff;
                if (uip->ui_proccnt > 0)
                        return (uip->ui_proccnt);
                if (uip->ui_proccnt < 0)
                        panic("chgproccnt: procs < 0");
                LIST_REMOVE(uip, ui_hash);
                FREE_ZONE(uip, sizeof *uip, M_PROC);
                return (0);
        }
        if (diff <= 0) {
                if (diff == 0)
                        return(0);
                panic("chgproccnt: lost user");
        }
        MALLOC_ZONE(uip, struct uidinfo *, sizeof(*uip), M_PROC, M_WAITOK);
        LIST_INSERT_HEAD(uipp, uip, ui_hash);
        uip->ui_uid = uid;
        uip->ui_proccnt = diff;
        return (diff);
}

/*
 * Is p an inferior of the current process?
 */
int
inferior(p)
        register struct proc *p;
{

        for (; p != current_proc(); p = p->p_pptr)
                if (p->p_pid == 0)
                        return (0);
        return (1);
}
/*
 * Is p an inferior of t ?
 */
int
isinferior(struct proc *p, register struct proc *t)
{

        /* if p==t they are not inferior */
        if (p == t)
                return(0);
        for (; p != t; p = p->p_pptr)
                if (p->p_pid == 0)
                        return (0);
        return (1);
}

/*
 * Locate a process by number
 */
struct proc *
pfind(pid)
        register pid_t pid;
{
        register struct proc *p;

        if (!pid)
                return (kernproc);

        for (p = PIDHASH(pid)->lh_first; p != 0; p = p->p_hash.le_next)
                if (p->p_pid == pid)
                        return (p);
        return (NULL);
}

/*
 * Locate a zombie by PID
 */
__private_extern__ struct proc *
pzfind(pid)
        register pid_t pid;
{
        register struct proc *p;

        for (p = zombproc.lh_first; p != 0; p = p->p_list.le_next)
                if (p->p_pid == pid)
                        return (p);
        return (NULL);
}

/*
 * Locate a process group by number
 */
struct pgrp *
pgfind(pgid)
        register pid_t pgid;
{
        register struct pgrp *pgrp;

        for (pgrp = PGRPHASH(pgid)->lh_first; pgrp != 0; pgrp = pgrp->pg_hash.le_next)
                if (pgrp->pg_id == pgid)
                        return (pgrp);
        return (NULL);
}


/*
 * Move p to a new or existing process group (and session)
 */
int
enterpgrp(p, pgid, mksess)
        register struct proc *p;
        pid_t pgid;
        int mksess;
{
        register struct pgrp *pgrp = pgfind(pgid);

#if DIAGNOSTIC
        if (pgrp != NULL && mksess)     /* firewalls */
                panic("enterpgrp: setsid into non-empty pgrp");
        if (SESS_LEADER(p))
                panic("enterpgrp: session leader attempted setpgrp");
#endif
        if (pgrp == NULL) {
                pid_t savepid = p->p_pid;
                struct proc *np;
                /*
                 * new process group
                 */
#if DIAGNOSTIC
                if (p->p_pid != pgid)
                        panic("enterpgrp: new pgrp and pid != pgid");
#endif
                MALLOC_ZONE(pgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP,
                    M_WAITOK);
                if ((np = pfind(savepid)) == NULL || np != p) {
                        FREE_ZONE(pgrp, sizeof(struct pgrp), M_PGRP);
                        return (ESRCH);
                }
                if (mksess) {
                        register struct session *sess;

                        /*
                         * new session
                         */
                        MALLOC_ZONE(sess, struct session *,
                                sizeof(struct session), M_SESSION, M_WAITOK);
                        sess->s_leader = p;
                        sess->s_sid = p->p_pid;
                        sess->s_count = 1;
                        sess->s_ttyvp = NULL;
                        sess->s_ttyp = NULL;
                        bcopy(p->p_session->s_login, sess->s_login,
                            sizeof(sess->s_login));
                        p->p_flag &= ~P_CONTROLT;
                        pgrp->pg_session = sess;
#if DIAGNOSTIC
                        if (p != current_proc())
                                panic("enterpgrp: mksession and p != curproc");
#endif
                } else {
                        pgrp->pg_session = p->p_session;
                        pgrp->pg_session->s_count++;
                }
                pgrp->pg_id = pgid;
                LIST_INIT(&pgrp->pg_members);
                LIST_INSERT_HEAD(PGRPHASH(pgid), pgrp, pg_hash);
                pgrp->pg_jobc = 0;
        } else if (pgrp == p->p_pgrp)
                return (0);

        /*
         * Adjust eligibility of affected pgrps to participate in job control.
         * Increment eligibility counts before decrementing, otherwise we
         * could reach 0 spuriously during the first call.
         */
        fixjobc(p, pgrp, 1);
        fixjobc(p, p->p_pgrp, 0);

        LIST_REMOVE(p, p_pglist);
        if (p->p_pgrp->pg_members.lh_first == 0)
                pgdelete(p->p_pgrp);
        p->p_pgrp = pgrp;
        LIST_INSERT_HEAD(&pgrp->pg_members, p, p_pglist);
        return (0);
}

/*
 * remove process from process group
 */
int
leavepgrp(p)
        register struct proc *p;
{

        LIST_REMOVE(p, p_pglist);
        if (p->p_pgrp->pg_members.lh_first == 0)
                pgdelete(p->p_pgrp);
        p->p_pgrp = 0;
        return (0);
}

/*
 * delete a process group
 */
void
pgdelete(pgrp)
        register struct pgrp *pgrp;
{

        if (pgrp->pg_session->s_ttyp != NULL && 
            pgrp->pg_session->s_ttyp->t_pgrp == pgrp)
                pgrp->pg_session->s_ttyp->t_pgrp = NULL;
        LIST_REMOVE(pgrp, pg_hash);
        if (--pgrp->pg_session->s_count == 0)
                FREE_ZONE(pgrp->pg_session, sizeof(struct session), M_SESSION);
        FREE_ZONE(pgrp, sizeof *pgrp, M_PGRP);
}

void
sessrele(sess)
        struct session *sess;
{
        if (--sess->s_count == 0)
                FREE_ZONE(sess, sizeof (struct session), M_SESSION);
}

/*
 * Adjust pgrp jobc counters when specified process changes process group.
 * We count the number of processes in each process group that "qualify"
 * the group for terminal job control (those with a parent in a different
 * process group of the same session).  If that count reaches zero, the
 * process group becomes orphaned.  Check both the specified process'
 * process group and that of its children.
 * entering == 0 => p is leaving specified group.
 * entering == 1 => p is entering specified group.
 */
void
fixjobc(struct proc *p, struct pgrp *pgrp, int entering)
{
        register struct pgrp *hispgrp;
        register struct session *mysession = pgrp->pg_session;

        /*
         * Check p's parent to see whether p qualifies its own process
         * group; if so, adjust count for p's process group.
         */
        if ((hispgrp = p->p_pptr->p_pgrp) != pgrp &&
            hispgrp->pg_session == mysession) {
                if (entering)
                        pgrp->pg_jobc++;
                else if (--pgrp->pg_jobc == 0)
                        orphanpg(pgrp);
        }

        /*
         * Check this process' children to see whether they qualify
         * their process groups; if so, adjust counts for children's
         * process groups.
         */
        for (p = p->p_children.lh_first; p != 0; p = p->p_sibling.le_next)
                if ((hispgrp = p->p_pgrp) != pgrp &&
                    hispgrp->pg_session == mysession &&
                    p->p_stat != SZOMB) {
                        if (entering)
                                hispgrp->pg_jobc++;
                        else if (--hispgrp->pg_jobc == 0)
                                orphanpg(hispgrp);
}
}

/* 
 * A process group has become orphaned;
 * if there are any stopped processes in the group,
 * hang-up all process in that group.
 */
static void
orphanpg(struct pgrp *pg)
{
        register struct proc *p;

        for (p = pg->pg_members.lh_first; p != 0; p = p->p_pglist.le_next) {
                if (p->p_stat == SSTOP) {
                        for (p = pg->pg_members.lh_first; p != 0;
                            p = p->p_pglist.le_next) {
                                pt_setrunnable(p);
                                psignal(p, SIGHUP);
                                psignal(p, SIGCONT);
                        }
                        return;
                }
        }
}

#ifdef DEBUG
void
pgrpdump()
{
        register struct pgrp *pgrp;
        register struct proc *p;
        register i;

        for (i = 0; i <= pgrphash; i++) {
                if (pgrp = pgrphashtbl[i].lh_first) {
                        printf("\tindx %d\n", i);
                        for (; pgrp != 0; pgrp = pgrp->pg_hash.le_next) {
                                printf("\tpgrp 0x%08x, pgid %d, sess %p, sesscnt %d, mem %p\n",
                                    pgrp, pgrp->pg_id, pgrp->pg_session,
                                    pgrp->pg_session->s_count,
                                    pgrp->pg_members.lh_first);
                                for (p = pgrp->pg_members.lh_first; p != 0;
                                    p = p->p_pglist.le_next) {
                                        printf("\t\tpid %d addr 0x%08x pgrp 0x%08x\n", 
                                            p->p_pid, p, p->p_pgrp);
                                }
                        }
                }
        }
}
#endif /* DEBUG */

/* XXX should be __private_extern__ */
int
proc_is_classic(struct proc *p)
{
    return (p->p_flag & P_CLASSIC) ? 1 : 0;
}

/* XXX Why does this function exist?  Need to kill it off... */
struct proc *
current_proc_EXTERNAL(void)
{
        return (current_proc());
}

/*
 * proc_core_name(name, uid, pid)
 * Expand the name described in corefilename, using name, uid, and pid.
 * corefilename is a printf-like string, with three format specifiers:
 *      %N      name of process ("name")
 *      %P      process id (pid)
 *      %U      user id (uid)
 * For example, "%N.core" is the default; they can be disabled completely
 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
 * This is controlled by the sysctl variable kern.corefile (see above).
 */
__private_extern__ char *
proc_core_name(const char *name, uid_t uid, pid_t pid)
{
        const char *format, *appendstr;
        char *temp;
        char id_buf[11];                /* Buffer for pid/uid -- max 4B */
        size_t i, l, n;

        format = corefilename;
        MALLOC(temp, char *, MAXPATHLEN, M_TEMP, M_NOWAIT | M_ZERO);
        if (temp == NULL)
                return (NULL);
        for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
                switch (format[i]) {
                case '%':       /* Format character */
                        i++;
                        switch (format[i]) {
                        case '%':
                                appendstr = "%";
                                break;
                        case 'N':       /* process name */
                                appendstr = name;
                                break;
                        case 'P':       /* process id */
                                sprintf(id_buf, "%u", pid);
                                appendstr = id_buf;
                                break;
                        case 'U':       /* user id */
                                sprintf(id_buf, "%u", uid);
                                appendstr = id_buf;
                                break;
                        default:
                                appendstr = "";
                                log(LOG_ERR,
                                    "Unknown format character %c in `%s'\n",
                                    format[i], format);
                        }
                        l = strlen(appendstr);
                        if ((n + l) >= MAXPATHLEN)
                                goto toolong;
                        bcopy(appendstr, temp + n, l);
                        n += l;
                        break;
                default:
                        temp[n++] = format[i];
                }
        }
        if (format[i] != '\0')
                goto toolong;
        return (temp);
toolong:
        log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too long\n",
            (long)pid, name, (u_long)uid);
        FREE(temp, M_TEMP);
        return (NULL);
}