sys/kern/kern_proc.c

/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	@(#)kern_proc.c	7.3 (Berkeley) 10/18/88
 */

#include "../machine/reg.h"
#include "../machine/pte.h"
#include "../machine/psl.h"

#include "param.h"
#include "systm.h"
#include "map.h"
#include "dir.h"
#include "user.h"
#include "kernel.h"
#include "proc.h"
#include "buf.h"
#include "seg.h"
#include "acct.h"
#include "wait.h"
#include "vm.h"
#include "text.h"
#include "file.h"
#include "quota.h"
#include "uio.h"
#include "malloc.h"
#include "mbuf.h"
#include "tty.h"

/*
 * Clear any pending stops for top and all descendents.
 */
spgrp(top)
	struct proc *top;
{
	register struct proc *p;
	int f = 0;

	p = top;
	for (;;) {
		p->p_sig &=
			  ~(sigmask(SIGTSTP)|sigmask(SIGTTIN)|sigmask(SIGTTOU));
		f++;
		/*
		 * If this process has children, descend to them next,
		 * otherwise do any siblings, and if done with this level,
		 * follow back up the tree (but not past top).
		 */
		if (p->p_cptr)
			p = p->p_cptr;
		else if (p == top)
			return (f);
		else if (p->p_osptr)
			p = p->p_osptr;
		else for (;;) {
			p = p->p_pptr;
			if (p == top)
				return (f);
			if (p->p_osptr) {
				p = p->p_osptr;
				break;
			}
		}
	}
}

/*
 * Is p an inferior of the current process?
 */
inferior(p)
	register struct proc *p;
{
	for (; p != u.u_procp; p = p->p_pptr)
		if (p->p_ppid == 0)
			return (0);
	return (1);
}

struct proc *
pfind(pid)
	register pid;
{
	register struct proc *p;

	for (p = &proc[pidhash[PIDHASH(pid)]] ;
	     p != &proc[0]; p = &proc[p->p_idhash])
		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)
 */
pgmv(p, pgid, mksess)
	register struct proc *p;
	pid_t pgid;
{
	register struct pgrp *pgrp = pgfind(pgid);
	register struct proc **pp = &p->p_pgrp->pg_mem;
	register struct proc *cp;
	register n;

	if (pgrp && mksess)	/* firewalls */
		panic("pgmv: setsid into non-empty pgrp %d\n", pgid);
	if (SESS_LEADER(p))
		panic("pgmv: session leader attempted setpgrp\n");
	if (!pgrp) {
		/*
		 * new process group
		 */
		if (p->p_pid != pgid)
			panic("pgmv: new pgrp and pid != pgid\n");
		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;
			pgrp->pg_session = sess;
			if (p != u.u_procp)
				panic("pgmv: mksession and p != u.u_procp");
			u.u_ttyp = 0;
			u.u_ttyd = 0;
		} 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 = 0;
	}
	/*
	 * adjust eligibility of affected pgrps to participate in job control
	 */
	if (PGRP_JOBC(p))
		p->p_pgrp->pg_jobc--;
	for (cp = p->p_cptr; cp; cp = cp->p_osptr)
		if (PGRP_JOBC(cp))
			cp->p_pgrp->pg_jobc--;
	/*
	 * unlink p from old process group
	 */
	for (; *pp; pp = &(*pp)->p_pgrpnxt)
		if (*pp == p) {
			*pp = p->p_pgrpnxt;
			goto done;
		}
	panic("pgmv: can't find p on old pgrp\n");
done:
	/*
	 * link into new one
	 */
	p->p_pgrpnxt = pgrp->pg_mem;
	pgrp->pg_mem = p;
	p->p_pgrp = pgrp;
	/*
	 * adjust eligibility of affected pgrps to participate in job control
	 */
	if (PGRP_JOBC(p))
		p->p_pgrp->pg_jobc++;
	for (cp = p->p_cptr; cp; cp = cp->p_osptr)
		if (PGRP_JOBC(cp))
			cp->p_pgrp->pg_jobc++;
	/*
	 * old pgrp empty?
	 */
	if (!p->p_pgrp->pg_mem)
		pgdelete(p->p_pgrp);
}

/*
 * remove process from process group
 */
pgrm(p)
	register struct proc *p;
{
	register struct proc **pp = &p->p_pgrp->pg_mem;
	register struct proc *cp;

	for (; *pp; pp = &(*pp)->p_pgrpnxt)
		if (*pp == p) {
			*pp = p->p_pgrpnxt;
			goto done;
		}
	panic("pgrm: can't find p in pgrp\n");
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)];

	for (; *pgp; pgp = &(*pgp)->pg_hforw)
		if (*pgp == pgrp) {
			*pgp = pgrp->pg_hforw;
			goto done;
		}
	panic("pgdelete: can't find pgrp on hash chain\n");
done:
	if (--pgrp->pg_session->s_count == 0)
		FREE(pgrp->pg_session, M_SESSION);
	FREE(pgrp, M_PGRP);
}

/*
 * init the process queues
 */
pqinit()
{
	register struct proc *p;

	/*
	 * most procs are initially on freequeue
	 *	nb: we place them there in their "natural" order.
	 */

	freeproc = NULL;
	for (p = procNPROC; --p > proc; freeproc = p)
		p->p_nxt = freeproc;

	/*
	 * but proc[0] is special ...
	 */

	allproc = p;
	p->p_nxt = NULL;
	p->p_prev = &allproc;

	zombproc = NULL;
}

/* 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);
		    }
		  }

		}
	}
}