Source to kern/kern_proc.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_proc.c 7.16 (Berkeley) 6/28/91
*/
#include "param.h"
#include "systm.h"
#include "kernel.h"
#include "proc.h"
#include "buf.h"
#include "acct.h"
#include "wait.h"
#include "file.h"
#include "../ufs/quota.h"
#include "uio.h"
#include "malloc.h"
#include "mbuf.h"
#include "ioctl.h"
#include "tty.h"
/*
* Is p an inferior of the current process?
*/
inferior(p)
register struct proc *p;
{
for (; p != curproc; p = p->p_pptr)
if (p->p_pid == 0)
return (0);
return (1);
}
/*
* Locate a process by number
*/
struct proc *
pfind(pid)
register pid;
{
register struct proc *p = pidhash[PIDHASH(pid)];
for (; p; p = p->p_hash)
if (p->p_pid == pid)
return (p);
return ((struct proc *)0);
}
/*
* Locate a process group by number
*/
struct pgrp *
pgfind(pgid)
register pid_t pgid;
{
register struct pgrp *pgrp = pgrphash[PIDHASH(pgid)];
for (; pgrp; pgrp = pgrp->pg_hforw)
if (pgrp->pg_id == pgid)
return (pgrp);
return ((struct pgrp *)0);
}
/*
* Move p to a new or existing process group (and session)
*/
enterpgrp(p, pgid, mksess)
register struct proc *p;
pid_t pgid;
{
register struct pgrp *pgrp = pgfind(pgid);
register struct proc **pp;
register struct proc *cp;
int n;
#ifdef DIAGNOSTIC
if (pgrp && mksess) /* firewalls */
panic("enterpgrp: setsid into non-empty pgrp");
if (SESS_LEADER(p))
panic("enterpgrp: session leader attempted setpgrp");
#endif
if (pgrp == NULL) {
/*
* new process group
*/
#ifdef DIAGNOSTIC
if (p->p_pid != pgid)
panic("enterpgrp: new pgrp and pid != pgid");
#endif
MALLOC(pgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP,
M_WAITOK);
if (mksess) {
register struct session *sess;
/*
* new session
*/
MALLOC(sess, struct session *, sizeof(struct session),
M_SESSION, M_WAITOK);
sess->s_leader = p;
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 &= ~SCTTY;
pgrp->pg_session = sess;
#ifdef DIAGNOSTIC
if (p != curproc)
panic("enterpgrp: mksession and p != curproc");
#endif
} else {
pgrp->pg_session = p->p_session;
pgrp->pg_session->s_count++;
}
pgrp->pg_id = pgid;
pgrp->pg_hforw = pgrphash[n = PIDHASH(pgid)];
pgrphash[n] = pgrp;
pgrp->pg_jobc = 0;
pgrp->pg_mem = NULL;
} else if (pgrp == p->p_pgrp)
return;
/*
* 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);
/*
* unlink p from old process group
*/
for (pp = &p->p_pgrp->pg_mem; *pp; pp = &(*pp)->p_pgrpnxt)
if (*pp == p) {
*pp = p->p_pgrpnxt;
goto done;
}
panic("enterpgrp: can't find p on old pgrp");
done:
/*
* delete old if empty
*/
if (p->p_pgrp->pg_mem == 0)
pgdelete(p->p_pgrp);
/*
* link into new one
*/
p->p_pgrp = pgrp;
p->p_pgrpnxt = pgrp->pg_mem;
pgrp->pg_mem = p;
}
/*
* remove process from process group
*/
leavepgrp(p)
register struct proc *p;
{
register struct proc **pp = &p->p_pgrp->pg_mem;
for (; *pp; pp = &(*pp)->p_pgrpnxt)
if (*pp == p) {
*pp = p->p_pgrpnxt;
goto done;
}
panic("leavepgrp: can't find p in pgrp");
done:
if (!p->p_pgrp->pg_mem)
pgdelete(p->p_pgrp);
p->p_pgrp = 0;
}
/*
* delete a process group
*/
pgdelete(pgrp)
register struct pgrp *pgrp;
{
register struct pgrp **pgp = &pgrphash[PIDHASH(pgrp->pg_id)];
if (pgrp->pg_session->s_ttyp != NULL &&
pgrp->pg_session->s_ttyp->t_pgrp == pgrp)
pgrp->pg_session->s_ttyp->t_pgrp = NULL;
for (; *pgp; pgp = &(*pgp)->pg_hforw)
if (*pgp == pgrp) {
*pgp = pgrp->pg_hforw;
goto done;
}
panic("pgdelete: can't find pgrp on hash chain");
done:
if (--pgrp->pg_session->s_count == 0)
FREE(pgrp->pg_session, M_SESSION);
FREE(pgrp, M_PGRP);
}
static orphanpg();
/*
* 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.
*/
fixjobc(p, pgrp, entering)
register struct proc *p;
register 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_cptr; p; p = p->p_osptr)
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
orphanpg(pg)
struct pgrp *pg;
{
register struct proc *p;
for (p = pg->pg_mem; p; p = p->p_pgrpnxt) {
if (p->p_stat == SSTOP) {
for (p = pg->pg_mem; p; p = p->p_pgrpnxt) {
psignal(p, SIGHUP);
psignal(p, SIGCONT);
}
return;
}
}
}
#ifdef debug
/* DEBUG */
pgrpdump()
{
register struct pgrp *pgrp;
register struct proc *p;
register i;
for (i=0; i<PIDHSZ; i++) {
if (pgrphash[i]) {
printf("\tindx %d\n", i);
for (pgrp=pgrphash[i]; pgrp; pgrp=pgrp->pg_hforw) {
printf("\tpgrp %x, pgid %d, sess %x, sesscnt %d, mem %x\n",
pgrp, pgrp->pg_id, pgrp->pg_session,
pgrp->pg_session->s_count, pgrp->pg_mem);
for (p=pgrp->pg_mem; p; p=p->p_pgrpnxt) {
printf("\t\tpid %d addr %x pgrp %x\n",
p->p_pid, p, p->p_pgrp);
}
}
}
}
}
#endif /* debug */