kern_proc.c revision 3451 
1/*
2 * Copyright (c) 1982, 1986, 1989, 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 *	@(#)kern_proc.c	8.4 (Berkeley) 1/4/94
34 * $Id: kern_proc.c,v 1.7 1994/10/02 04:45:48 davidg Exp $
35 */
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/kernel.h>
40#include <sys/proc.h>
41#include <sys/buf.h>
42#include <sys/acct.h>
43#include <sys/wait.h>
44#include <sys/file.h>
45#include <ufs/ufs/quota.h>
46#include <sys/uio.h>
47#include <sys/malloc.h>
48#include <sys/mbuf.h>
49#include <sys/ioctl.h>
50#include <sys/tty.h>
51#include <sys/signalvar.h>
52
53struct prochd qs[NQS];		/* as good a place as any... */
54struct prochd rtqs[NQS];	/* Space for REALTIME queues too */
55struct prochd idqs[NQS];	/* Space for IDLE queues too */
56
57volatile struct proc *allproc;	/* all processes */
58struct proc *zombproc;		/* just zombies */
59
60void pgdelete	__P((struct pgrp *));
61void fixjobc	__P((struct proc *, struct pgrp *, int));
62
63/*
64 * Structure associated with user cacheing.
65 */
66struct uidinfo {
67	struct	uidinfo *ui_next;
68	struct	uidinfo **ui_prev;
69	uid_t	ui_uid;
70	long	ui_proccnt;
71} **uihashtbl;
72u_long	uihash;		/* size of hash table - 1 */
73#define	UIHASH(uid)	((uid) & uihash)
74
75/*
76 * Allocate a hash table.
77 */
78void
79usrinfoinit()
80{
81
82	uihashtbl = hashinit(maxproc / 16, M_PROC, &uihash);
83}
84
85/*
86 * Change the count associated with number of processes
87 * a given user is using.
88 */
89int
90chgproccnt(uid, diff)
91	uid_t	uid;
92	int	diff;
93{
94	register struct uidinfo **uipp, *uip, *uiq;
95
96	uipp = &uihashtbl[UIHASH(uid)];
97	for (uip = *uipp; uip; uip = uip->ui_next)
98		if (uip->ui_uid == uid)
99			break;
100	if (uip) {
101		uip->ui_proccnt += diff;
102		if (uip->ui_proccnt > 0)
103			return (uip->ui_proccnt);
104		if (uip->ui_proccnt < 0)
105			panic("chgproccnt: procs < 0");
106		if ((uiq = uip->ui_next))
107			uiq->ui_prev = uip->ui_prev;
108		*uip->ui_prev = uiq;
109		FREE(uip, M_PROC);
110		return (0);
111	}
112	if (diff <= 0) {
113		if (diff == 0)
114			return(0);
115		panic("chgproccnt: lost user");
116	}
117	MALLOC(uip, struct uidinfo *, sizeof(*uip), M_PROC, M_WAITOK);
118	if ((uiq = *uipp))
119		uiq->ui_prev = &uip->ui_next;
120	uip->ui_next = uiq;
121	uip->ui_prev = uipp;
122	*uipp = uip;
123	uip->ui_uid = uid;
124	uip->ui_proccnt = diff;
125	return (diff);
126}
127
128/*
129 * Is p an inferior of the current process?
130 */
131int
132inferior(p)
133	register struct proc *p;
134{
135
136	for (; p != curproc; p = p->p_pptr)
137		if (p->p_pid == 0)
138			return (0);
139	return (1);
140}
141
142/*
143 * Locate a process by number
144 */
145struct proc *
146pfind(pid)
147	register pid_t pid;
148{
149	register struct proc *p;
150
151	for (p = pidhash[PIDHASH(pid)]; p != NULL; p = p->p_hash)
152		if (p->p_pid == pid)
153			return (p);
154	return (NULL);
155}
156
157/*
158 * Locate a process group by number
159 */
160struct pgrp *
161pgfind(pgid)
162	register pid_t pgid;
163{
164	register struct pgrp *pgrp;
165
166	for (pgrp = pgrphash[PIDHASH(pgid)];
167	    pgrp != NULL; pgrp = pgrp->pg_hforw)
168		if (pgrp->pg_id == pgid)
169			return (pgrp);
170	return (NULL);
171}
172
173/*
174 * Move p to a new or existing process group (and session)
175 */
176int
177enterpgrp(p, pgid, mksess)
178	register struct proc *p;
179	pid_t pgid;
180	int mksess;
181{
182	register struct pgrp *pgrp = pgfind(pgid);
183	register struct proc **pp;
184	int n;
185
186#ifdef DIAGNOSTIC
187	if (pgrp != NULL && mksess)	/* firewalls */
188		panic("enterpgrp: setsid into non-empty pgrp");
189	if (SESS_LEADER(p))
190		panic("enterpgrp: session leader attempted setpgrp");
191#endif
192	if (pgrp == NULL) {
193		pid_t savepid = p->p_pid;
194		struct proc *np;
195		/*
196		 * new process group
197		 */
198#ifdef DIAGNOSTIC
199		if (p->p_pid != pgid)
200			panic("enterpgrp: new pgrp and pid != pgid");
201#endif
202		MALLOC(pgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP,
203		       M_WAITOK);
204		if ((np = pfind(savepid)) == NULL || np != p)
205			return (ESRCH);
206		if (mksess) {
207			register struct session *sess;
208
209			/*
210			 * new session
211			 */
212			MALLOC(sess, struct session *, sizeof(struct session),
213				M_SESSION, M_WAITOK);
214			sess->s_leader = p;
215			sess->s_count = 1;
216			sess->s_ttyvp = NULL;
217			sess->s_ttyp = NULL;
218			bcopy(p->p_session->s_login, sess->s_login,
219			    sizeof(sess->s_login));
220			p->p_flag &= ~P_CONTROLT;
221			pgrp->pg_session = sess;
222#ifdef DIAGNOSTIC
223			if (p != curproc)
224				panic("enterpgrp: mksession and p != curproc");
225#endif
226		} else {
227			pgrp->pg_session = p->p_session;
228			pgrp->pg_session->s_count++;
229		}
230		pgrp->pg_id = pgid;
231		pgrp->pg_hforw = pgrphash[n = PIDHASH(pgid)];
232		pgrphash[n] = pgrp;
233		pgrp->pg_jobc = 0;
234		pgrp->pg_mem = NULL;
235	} else if (pgrp == p->p_pgrp)
236		return (0);
237
238	/*
239	 * Adjust eligibility of affected pgrps to participate in job control.
240	 * Increment eligibility counts before decrementing, otherwise we
241	 * could reach 0 spuriously during the first call.
242	 */
243	fixjobc(p, pgrp, 1);
244	fixjobc(p, p->p_pgrp, 0);
245
246	/*
247	 * unlink p from old process group
248	 */
249	for (pp = &p->p_pgrp->pg_mem; *pp; pp = &(*pp)->p_pgrpnxt) {
250		if (*pp == p) {
251			*pp = p->p_pgrpnxt;
252			break;
253		}
254	}
255#ifdef DIAGNOSTIC
256	if (pp == NULL)
257		panic("enterpgrp: can't find p on old pgrp");
258#endif
259	/*
260	 * delete old if empty
261	 */
262	if (p->p_pgrp->pg_mem == 0)
263		pgdelete(p->p_pgrp);
264	/*
265	 * link into new one
266	 */
267	p->p_pgrp = pgrp;
268	p->p_pgrpnxt = pgrp->pg_mem;
269	pgrp->pg_mem = p;
270	return (0);
271}
272
273/*
274 * remove process from process group
275 */
276int
277leavepgrp(p)
278	register struct proc *p;
279{
280	register struct proc **pp = &p->p_pgrp->pg_mem;
281
282	for (; *pp; pp = &(*pp)->p_pgrpnxt) {
283		if (*pp == p) {
284			*pp = p->p_pgrpnxt;
285			break;
286		}
287	}
288#ifdef DIAGNOSTIC
289	if (pp == NULL)
290		panic("leavepgrp: can't find p in pgrp");
291#endif
292	if (!p->p_pgrp->pg_mem)
293		pgdelete(p->p_pgrp);
294	p->p_pgrp = 0;
295	return (0);
296}
297
298/*
299 * delete a process group
300 */
301void
302pgdelete(pgrp)
303	register struct pgrp *pgrp;
304{
305	register struct pgrp **pgp = &pgrphash[PIDHASH(pgrp->pg_id)];
306
307	if (pgrp->pg_session->s_ttyp != NULL &&
308	    pgrp->pg_session->s_ttyp->t_pgrp == pgrp)
309		pgrp->pg_session->s_ttyp->t_pgrp = NULL;
310	for (; *pgp; pgp = &(*pgp)->pg_hforw) {
311		if (*pgp == pgrp) {
312			*pgp = pgrp->pg_hforw;
313			break;
314		}
315	}
316#ifdef DIAGNOSTIC
317	if (pgp == NULL)
318		panic("pgdelete: can't find pgrp on hash chain");
319#endif
320	if (--pgrp->pg_session->s_count == 0)
321		FREE(pgrp->pg_session, M_SESSION);
322	FREE(pgrp, M_PGRP);
323}
324
325static void orphanpg();
326
327/*
328 * Adjust pgrp jobc counters when specified process changes process group.
329 * We count the number of processes in each process group that "qualify"
330 * the group for terminal job control (those with a parent in a different
331 * process group of the same session).  If that count reaches zero, the
332 * process group becomes orphaned.  Check both the specified process'
333 * process group and that of its children.
334 * entering == 0 => p is leaving specified group.
335 * entering == 1 => p is entering specified group.
336 */
337void
338fixjobc(p, pgrp, entering)
339	register struct proc *p;
340	register struct pgrp *pgrp;
341	int entering;
342{
343	register struct pgrp *hispgrp;
344	register struct session *mysession = pgrp->pg_session;
345
346	/*
347	 * Check p's parent to see whether p qualifies its own process
348	 * group; if so, adjust count for p's process group.
349	 */
350	if ((hispgrp = p->p_pptr->p_pgrp) != pgrp &&
351	    hispgrp->pg_session == mysession)
352		if (entering)
353			pgrp->pg_jobc++;
354		else if (--pgrp->pg_jobc == 0)
355			orphanpg(pgrp);
356
357	/*
358	 * Check this process' children to see whether they qualify
359	 * their process groups; if so, adjust counts for children's
360	 * process groups.
361	 */
362	for (p = p->p_cptr; p; p = p->p_osptr)
363		if ((hispgrp = p->p_pgrp) != pgrp &&
364		    hispgrp->pg_session == mysession &&
365		    p->p_stat != SZOMB)
366			if (entering)
367				hispgrp->pg_jobc++;
368			else if (--hispgrp->pg_jobc == 0)
369				orphanpg(hispgrp);
370}
371
372/*
373 * A process group has become orphaned;
374 * if there are any stopped processes in the group,
375 * hang-up all process in that group.
376 */
377static void
378orphanpg(pg)
379	struct pgrp *pg;
380{
381	register struct proc *p;
382
383	for (p = pg->pg_mem; p; p = p->p_pgrpnxt) {
384		if (p->p_stat == SSTOP) {
385			for (p = pg->pg_mem; p; p = p->p_pgrpnxt) {
386				psignal(p, SIGHUP);
387				psignal(p, SIGCONT);
388			}
389			return;
390		}
391	}
392}
393
394#ifdef debug
395/* DEBUG */
396pgrpdump()
397{
398	register struct pgrp *pgrp;
399	register struct proc *p;
400	register i;
401
402	for (i=0; i<PIDHSZ; i++) {
403		if (pgrphash[i]) {
404		  printf("\tindx %d\n", i);
405		  for (pgrp=pgrphash[i]; pgrp; pgrp=pgrp->pg_hforw) {
406		    printf("\tpgrp %x, pgid %d, sess %x, sesscnt %d, mem %x\n",
407			pgrp, pgrp->pg_id, pgrp->pg_session,
408			pgrp->pg_session->s_count, pgrp->pg_mem);
409		    for (p=pgrp->pg_mem; p; p=p->p_pgrpnxt) {
410			printf("\t\tpid %d addr %x pgrp %x\n",
411				p->p_pid, p, p->p_pgrp);
412		    }
413		  }
414
415		}
416	}
417}
418#endif /* debug */
419