1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright 2013, Joyent, Inc. All rights reserved.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 #include <sys/types.h>
31 #include <sys/param.h>
32 #include <sys/sysmacros.h>
33 #include <sys/signal.h>
34 #include <sys/cred.h>
35 #include <sys/policy.h>
36 #include <sys/user.h>
37 #include <sys/systm.h>
38 #include <sys/cpuvar.h>
39 #include <sys/vfs.h>
40 #include <sys/vnode.h>
41 #include <sys/file.h>
42 #include <sys/errno.h>
43 #include <sys/time.h>
44 #include <sys/proc.h>
45 #include <sys/cmn_err.h>
46 #include <sys/acct.h>
47 #include <sys/tuneable.h>
48 #include <sys/class.h>
49 #include <sys/kmem.h>
50 #include <sys/session.h>
51 #include <sys/ucontext.h>
52 #include <sys/stack.h>
53 #include <sys/procfs.h>
54 #include <sys/prsystm.h>
55 #include <sys/vmsystm.h>
56 #include <sys/vtrace.h>
57 #include <sys/debug.h>
58 #include <sys/shm_impl.h>
59 #include <sys/door_data.h>
60 #include <vm/as.h>
61 #include <vm/rm.h>
62 #include <c2/audit.h>
63 #include <sys/var.h>
64 #include <sys/schedctl.h>
65 #include <sys/utrap.h>
66 #include <sys/task.h>
67 #include <sys/resource.h>
68 #include <sys/cyclic.h>
69 #include <sys/lgrp.h>
70 #include <sys/rctl.h>
71 #include <sys/contract_impl.h>
72 #include <sys/contract/process_impl.h>
73 #include <sys/list.h>
74 #include <sys/dtrace.h>
75 #include <sys/pool.h>
76 #include <sys/zone.h>
77 #include <sys/sdt.h>
78 #include <sys/class.h>
79 #include <sys/corectl.h>
80 #include <sys/brand.h>
81 #include <sys/fork.h>
82
83 static int64_t cfork(int, int, int);
84 static int getproc(proc_t **, pid_t, uint_t);
85 #define GETPROC_USER 0x0
86 #define GETPROC_KERNEL 0x1
87
88 static void fork_fail(proc_t *);
89 static void forklwp_fail(proc_t *);
90
91 int fork_fail_pending;
92
93 extern struct kmem_cache *process_cache;
94
95 /*
96 * The vfork() system call trap is no longer invoked by libc.
97 * It is retained only for the benefit of applications running
98 * within a solaris10 branded zone. It should be eliminated
99 * when we no longer support solaris10 branded zones.
100 */
101 int64_t
102 vfork(void)
103 {
104 curthread->t_post_sys = 1; /* so vfwait() will be called */
105 return (cfork(1, 1, 0));
106 }
107
108 /*
109 * forksys system call - forkx, forkallx, vforkx. This is the
110 * interface invoked by libc for fork1(), forkall(), and vfork()
111 */
112 int64_t
113 forksys(int subcode, int flags)
114 {
115 switch (subcode) {
116 case 0:
117 return (cfork(0, 1, flags)); /* forkx(flags) */
118 case 1:
119 return (cfork(0, 0, flags)); /* forkallx(flags) */
120 case 2:
121 curthread->t_post_sys = 1; /* so vfwait() will be called */
122 return (cfork(1, 1, flags)); /* vforkx(flags) */
123 default:
124 return ((int64_t)set_errno(EINVAL));
125 }
126 }
127
128 /* ARGSUSED */
129 static int64_t
130 cfork(int isvfork, int isfork1, int flags)
131 {
132 proc_t *p = ttoproc(curthread);
133 struct as *as;
134 proc_t *cp, **orphpp;
135 klwp_t *clone;
136 kthread_t *t;
137 task_t *tk;
138 rval_t r;
139 int error;
140 int i;
141 rctl_set_t *dup_set;
142 rctl_alloc_gp_t *dup_gp;
143 rctl_entity_p_t e;
144 lwpdir_t *ldp;
145 lwpent_t *lep;
146 lwpent_t *clep;
147
148 /*
149 * Allow only these two flags.
150 */
151 if ((flags & ~(FORK_NOSIGCHLD | FORK_WAITPID)) != 0) {
152 error = EINVAL;
153 atomic_inc_32(&curproc->p_zone->zone_ffmisc);
154 goto forkerr;
155 }
156
157 /*
158 * fork is not supported for the /proc agent lwp.
159 */
160 if (curthread == p->p_agenttp) {
161 error = ENOTSUP;
162 atomic_inc_32(&curproc->p_zone->zone_ffmisc);
163 goto forkerr;
164 }
165
166 if ((error = secpolicy_basic_fork(CRED())) != 0) {
167 atomic_inc_32(&p->p_zone->zone_ffmisc);
168 goto forkerr;
169 }
170
171 /*
172 * If the calling lwp is doing a fork1() then the
173 * other lwps in this process are not duplicated and
174 * don't need to be held where their kernel stacks can be
175 * cloned. If doing forkall(), the process is held with
176 * SHOLDFORK, so that the lwps are at a point where their
177 * stacks can be copied which is on entry or exit from
178 * the kernel.
179 */
180 if (!holdlwps(isfork1 ? SHOLDFORK1 : SHOLDFORK)) {
181 aston(curthread);
182 error = EINTR;
183 atomic_inc_32(&p->p_zone->zone_ffmisc);
184 goto forkerr;
185 }
186
187 #if defined(__sparc)
188 /*
189 * Ensure that the user stack is fully constructed
190 * before creating the child process structure.
191 */
192 (void) flush_user_windows_to_stack(NULL);
193 #endif
194
195 mutex_enter(&p->p_lock);
196 /*
197 * If this is vfork(), cancel any suspend request we might
198 * have gotten from some other thread via lwp_suspend().
199 * Otherwise we could end up with a deadlock on return
200 * from the vfork() in both the parent and the child.
201 */
202 if (isvfork)
203 curthread->t_proc_flag &= ~TP_HOLDLWP;
204 /*
205 * Prevent our resource set associations from being changed during fork.
206 */
207 pool_barrier_enter();
208 mutex_exit(&p->p_lock);
209
210 /*
211 * Create a child proc struct. Place a VN_HOLD on appropriate vnodes.
212 */
213 if (getproc(&cp, 0, GETPROC_USER) < 0) {
214 mutex_enter(&p->p_lock);
215 pool_barrier_exit();
216 continuelwps(p);
217 mutex_exit(&p->p_lock);
218 error = EAGAIN;
219 goto forkerr;
220 }
221
222 TRACE_2(TR_FAC_PROC, TR_PROC_FORK, "proc_fork:cp %p p %p", cp, p);
223
224 /*
225 * Assign an address space to child
226 */
227 if (isvfork) {
228 /*
229 * Clear any watched areas and remember the
230 * watched pages for restoring in vfwait().
231 */
232 as = p->p_as;
233 if (avl_numnodes(&as->a_wpage) != 0) {
234 AS_LOCK_ENTER(as, RW_WRITER);
235 as_clearwatch(as);
236 p->p_wpage = as->a_wpage;
237 avl_create(&as->a_wpage, wp_compare,
238 sizeof (struct watched_page),
239 offsetof(struct watched_page, wp_link));
240 AS_LOCK_EXIT(as);
241 }
242 cp->p_as = as;
243 cp->p_flag |= SVFORK;
244
245 /*
246 * Use the parent's shm segment list information for
247 * the child as it uses its address space till it execs.
248 */
249 cp->p_segacct = p->p_segacct;
250 } else {
251 /*
252 * We need to hold P_PR_LOCK until the address space has
253 * been duplicated and we've had a chance to remove from the
254 * child any DTrace probes that were in the parent. Holding
255 * P_PR_LOCK prevents any new probes from being added and any
256 * extant probes from being removed.
257 */
258 mutex_enter(&p->p_lock);
259 sprlock_proc(p);
260 p->p_flag |= SFORKING;
261 mutex_exit(&p->p_lock);
262
263 error = as_dup(p->p_as, cp);
264 if (error != 0) {
265 mutex_enter(&p->p_lock);
266 sprunlock(p);
267 fork_fail(cp);
268 mutex_enter(&pidlock);
269 orphpp = &p->p_orphan;
270 while (*orphpp != cp)
271 orphpp = &(*orphpp)->p_nextorph;
272 *orphpp = cp->p_nextorph;
273 if (p->p_child == cp)
274 p->p_child = cp->p_sibling;
275 if (cp->p_sibling)
276 cp->p_sibling->p_psibling = cp->p_psibling;
277 if (cp->p_psibling)
278 cp->p_psibling->p_sibling = cp->p_sibling;
279 mutex_enter(&cp->p_lock);
280 tk = cp->p_task;
281 task_detach(cp);
282 ASSERT(cp->p_pool->pool_ref > 0);
283 atomic_dec_32(&cp->p_pool->pool_ref);
284 mutex_exit(&cp->p_lock);
285 pid_exit(cp, tk);
286 mutex_exit(&pidlock);
287 task_rele(tk);
288
289 mutex_enter(&p->p_lock);
290 p->p_flag &= ~SFORKING;
291 pool_barrier_exit();
292 continuelwps(p);
293 mutex_exit(&p->p_lock);
294 /*
295 * Preserve ENOMEM error condition but
296 * map all others to EAGAIN.
297 */
298 error = (error == ENOMEM) ? ENOMEM : EAGAIN;
299 atomic_inc_32(&p->p_zone->zone_ffnomem);
300 goto forkerr;
301 }
302
303 /*
304 * Remove all DTrace tracepoints from the child process. We
305 * need to do this _before_ duplicating USDT providers since
306 * any associated probes may be immediately enabled.
307 */
308 if (p->p_dtrace_count > 0)
309 dtrace_fasttrap_fork(p, cp);
310
311 mutex_enter(&p->p_lock);
312 sprunlock(p);
313
314 /* Duplicate parent's shared memory */
315 if (p->p_segacct)
316 shmfork(p, cp);
317
318 /*
319 * Duplicate any helper actions and providers. The SFORKING
320 * we set above informs the code to enable USDT probes that
321 * sprlock() may fail because the child is being forked.
322 */
323 if (p->p_dtrace_helpers != NULL) {
324 ASSERT(dtrace_helpers_fork != NULL);
325 (*dtrace_helpers_fork)(p, cp);
326 }
327
328 mutex_enter(&p->p_lock);
329 p->p_flag &= ~SFORKING;
330 mutex_exit(&p->p_lock);
331 }
332
333 /*
334 * Duplicate parent's resource controls.
335 */
336 dup_set = rctl_set_create();
337 for (;;) {
338 dup_gp = rctl_set_dup_prealloc(p->p_rctls);
339 mutex_enter(&p->p_rctls->rcs_lock);
340 if (rctl_set_dup_ready(p->p_rctls, dup_gp))
341 break;
342 mutex_exit(&p->p_rctls->rcs_lock);
343 rctl_prealloc_destroy(dup_gp);
344 }
345 e.rcep_p.proc = cp;
346 e.rcep_t = RCENTITY_PROCESS;
347 cp->p_rctls = rctl_set_dup(p->p_rctls, p, cp, &e, dup_set, dup_gp,
348 RCD_DUP | RCD_CALLBACK);
349 mutex_exit(&p->p_rctls->rcs_lock);
350
351 rctl_prealloc_destroy(dup_gp);
352
353 /*
354 * Allocate the child's lwp directory and lwpid hash table.
355 */
356 if (isfork1)
357 cp->p_lwpdir_sz = 2;
358 else
359 cp->p_lwpdir_sz = p->p_lwpdir_sz;
360 cp->p_lwpdir = cp->p_lwpfree = ldp =
361 kmem_zalloc(cp->p_lwpdir_sz * sizeof (lwpdir_t), KM_SLEEP);
362 for (i = 1; i < cp->p_lwpdir_sz; i++, ldp++)
363 ldp->ld_next = ldp + 1;
364 cp->p_tidhash_sz = (cp->p_lwpdir_sz + 2) / 2;
365 cp->p_tidhash =
366 kmem_zalloc(cp->p_tidhash_sz * sizeof (tidhash_t), KM_SLEEP);
367
368 /*
369 * Duplicate parent's lwps.
370 * Mutual exclusion is not needed because the process is
371 * in the hold state and only the current lwp is running.
372 */
373 klgrpset_clear(cp->p_lgrpset);
374 if (isfork1) {
375 clone = forklwp(ttolwp(curthread), cp, curthread->t_tid);
376 if (clone == NULL)
377 goto forklwperr;
378 /*
379 * Inherit only the lwp_wait()able flag,
380 * Daemon threads should not call fork1(), but oh well...
381 */
382 lwptot(clone)->t_proc_flag |=
383 (curthread->t_proc_flag & TP_TWAIT);
384 } else {
385 /* this is forkall(), no one can be in lwp_wait() */
386 ASSERT(p->p_lwpwait == 0 && p->p_lwpdwait == 0);
387 /* for each entry in the parent's lwp directory... */
388 for (i = 0, ldp = p->p_lwpdir; i < p->p_lwpdir_sz; i++, ldp++) {
389 klwp_t *clwp;
390 kthread_t *ct;
391
392 if ((lep = ldp->ld_entry) == NULL)
393 continue;
394
395 if ((t = lep->le_thread) != NULL) {
396 clwp = forklwp(ttolwp(t), cp, t->t_tid);
397 if (clwp == NULL)
398 goto forklwperr;
399 ct = lwptot(clwp);
400 /*
401 * Inherit lwp_wait()able and daemon flags.
402 */
403 ct->t_proc_flag |=
404 (t->t_proc_flag & (TP_TWAIT|TP_DAEMON));
405 /*
406 * Keep track of the clone of curthread to
407 * post return values through lwp_setrval().
408 * Mark other threads for special treatment
409 * by lwp_rtt() / post_syscall().
410 */
411 if (t == curthread)
412 clone = clwp;
413 else
414 ct->t_flag |= T_FORKALL;
415 } else {
416 /*
417 * Replicate zombie lwps in the child.
418 */
419 clep = kmem_zalloc(sizeof (*clep), KM_SLEEP);
420 clep->le_lwpid = lep->le_lwpid;
421 clep->le_start = lep->le_start;
422 lwp_hash_in(cp, clep,
423 cp->p_tidhash, cp->p_tidhash_sz, 0);
424 }
425 }
426 }
427
428 /*
429 * Put new process in the parent's process contract, or put it
430 * in a new one if there is an active process template. Send a
431 * fork event (if requested) to whatever contract the child is
432 * a member of. Fails if the parent has been SIGKILLed.
433 */
434 if (contract_process_fork(NULL, cp, p, B_TRUE) == NULL) {
435 atomic_inc_32(&p->p_zone->zone_ffmisc);
436 goto forklwperr;
437 }
438
439 /*
440 * No fork failures occur beyond this point.
441 */
442
443 cp->p_lwpid = p->p_lwpid;
444 if (!isfork1) {
445 cp->p_lwpdaemon = p->p_lwpdaemon;
446 cp->p_zombcnt = p->p_zombcnt;
447 /*
448 * If the parent's lwp ids have wrapped around, so have the
449 * child's.
450 */
451 cp->p_flag |= p->p_flag & SLWPWRAP;
452 }
453
454 mutex_enter(&p->p_lock);
455 corectl_path_hold(cp->p_corefile = p->p_corefile);
456 corectl_content_hold(cp->p_content = p->p_content);
457 mutex_exit(&p->p_lock);
458
459 /*
460 * Duplicate process context ops, if any.
461 */
462 if (p->p_pctx)
463 forkpctx(p, cp);
464
465 #ifdef __sparc
466 utrap_dup(p, cp);
467 #endif
468 /*
469 * If the child process has been marked to stop on exit
470 * from this fork, arrange for all other lwps to stop in
471 * sympathy with the active lwp.
472 */
473 if (PTOU(cp)->u_systrap &&
474 prismember(&PTOU(cp)->u_exitmask, curthread->t_sysnum)) {
475 mutex_enter(&cp->p_lock);
476 t = cp->p_tlist;
477 do {
478 t->t_proc_flag |= TP_PRSTOP;
479 aston(t); /* so TP_PRSTOP will be seen */
480 } while ((t = t->t_forw) != cp->p_tlist);
481 mutex_exit(&cp->p_lock);
482 }
483 /*
484 * If the parent process has been marked to stop on exit
485 * from this fork, and its asynchronous-stop flag has not
486 * been set, arrange for all other lwps to stop before
487 * they return back to user level.
488 */
489 if (!(p->p_proc_flag & P_PR_ASYNC) && PTOU(p)->u_systrap &&
490 prismember(&PTOU(p)->u_exitmask, curthread->t_sysnum)) {
491 mutex_enter(&p->p_lock);
492 t = p->p_tlist;
493 do {
494 t->t_proc_flag |= TP_PRSTOP;
495 aston(t); /* so TP_PRSTOP will be seen */
496 } while ((t = t->t_forw) != p->p_tlist);
497 mutex_exit(&p->p_lock);
498 }
499
500 if (PROC_IS_BRANDED(p))
501 BROP(p)->b_lwp_setrval(clone, p->p_pid, 1);
502 else
503 lwp_setrval(clone, p->p_pid, 1);
504
505 /* set return values for parent */
506 r.r_val1 = (int)cp->p_pid;
507 r.r_val2 = 0;
508
509 /*
510 * pool_barrier_exit() can now be called because the child process has:
511 * - all identifying features cloned or set (p_pid, p_task, p_pool)
512 * - all resource sets associated (p_tlist->*->t_cpupart, p_as->a_mset)
513 * - any other fields set which are used in resource set binding.
514 */
515 mutex_enter(&p->p_lock);
516 pool_barrier_exit();
517 mutex_exit(&p->p_lock);
518
519 mutex_enter(&pidlock);
520 mutex_enter(&cp->p_lock);
521
522 /*
523 * Set flags telling the child what (not) to do on exit.
524 */
525 if (flags & FORK_NOSIGCHLD)
526 cp->p_pidflag |= CLDNOSIGCHLD;
527 if (flags & FORK_WAITPID)
528 cp->p_pidflag |= CLDWAITPID;
529
530 /*
531 * Now that there are lwps and threads attached, add the new
532 * process to the process group.
533 */
534 pgjoin(cp, p->p_pgidp);
535 cp->p_stat = SRUN;
536 /*
537 * We are now done with all the lwps in the child process.
538 */
539 t = cp->p_tlist;
540 do {
541 /*
542 * Set the lwp_suspend()ed lwps running.
543 * They will suspend properly at syscall exit.
544 */
545 if (t->t_proc_flag & TP_HOLDLWP)
546 lwp_create_done(t);
547 else {
548 /* set TS_CREATE to allow continuelwps() to work */
549 thread_lock(t);
550 ASSERT(t->t_state == TS_STOPPED &&
551 !(t->t_schedflag & (TS_CREATE|TS_CSTART)));
552 t->t_schedflag |= TS_CREATE;
553 thread_unlock(t);
554 }
555 } while ((t = t->t_forw) != cp->p_tlist);
556 mutex_exit(&cp->p_lock);
557
558 if (isvfork) {
559 CPU_STATS_ADDQ(CPU, sys, sysvfork, 1);
560 mutex_enter(&p->p_lock);
561 p->p_flag |= SVFWAIT;
562 curthread->t_flag |= T_VFPARENT;
563 DTRACE_PROC1(create, proc_t *, cp);
564 cv_broadcast(&pr_pid_cv[p->p_slot]); /* inform /proc */
565 mutex_exit(&p->p_lock);
566 /*
567 * Grab child's p_lock before dropping pidlock to ensure
568 * the process will not disappear before we set it running.
569 */
570 mutex_enter(&cp->p_lock);
571 mutex_exit(&pidlock);
572 sigdefault(cp);
573 continuelwps(cp);
574 mutex_exit(&cp->p_lock);
575 } else {
576 CPU_STATS_ADDQ(CPU, sys, sysfork, 1);
577 DTRACE_PROC1(create, proc_t *, cp);
578 /*
579 * It is CL_FORKRET's job to drop pidlock.
580 * If we do it here, the process could be set running
581 * and disappear before CL_FORKRET() is called.
582 */
583 CL_FORKRET(curthread, cp->p_tlist);
584 schedctl_set_cidpri(curthread);
585 ASSERT(MUTEX_NOT_HELD(&pidlock));
586 }
587
588 return (r.r_vals);
589
590 forklwperr:
591 if (isvfork) {
592 if (avl_numnodes(&p->p_wpage) != 0) {
593 /* restore watchpoints to parent */
594 as = p->p_as;
595 AS_LOCK_ENTER(as, RW_WRITER);
596 as->a_wpage = p->p_wpage;
597 avl_create(&p->p_wpage, wp_compare,
598 sizeof (struct watched_page),
599 offsetof(struct watched_page, wp_link));
600 as_setwatch(as);
601 AS_LOCK_EXIT(as);
602 }
603 } else {
604 if (cp->p_segacct)
605 shmexit(cp);
606 as = cp->p_as;
607 cp->p_as = &kas;
608 as_free(as);
609 }
610
611 if (cp->p_lwpdir) {
612 for (i = 0, ldp = cp->p_lwpdir; i < cp->p_lwpdir_sz; i++, ldp++)
613 if ((lep = ldp->ld_entry) != NULL)
614 kmem_free(lep, sizeof (*lep));
615 kmem_free(cp->p_lwpdir,
616 cp->p_lwpdir_sz * sizeof (*cp->p_lwpdir));
617 }
618 cp->p_lwpdir = NULL;
619 cp->p_lwpfree = NULL;
620 cp->p_lwpdir_sz = 0;
621
622 if (cp->p_tidhash)
623 kmem_free(cp->p_tidhash,
624 cp->p_tidhash_sz * sizeof (*cp->p_tidhash));
625 cp->p_tidhash = NULL;
626 cp->p_tidhash_sz = 0;
627
628 forklwp_fail(cp);
629 fork_fail(cp);
630 rctl_set_free(cp->p_rctls);
631 mutex_enter(&pidlock);
632
633 /*
634 * Detach failed child from task.
635 */
636 mutex_enter(&cp->p_lock);
637 tk = cp->p_task;
638 task_detach(cp);
639 ASSERT(cp->p_pool->pool_ref > 0);
640 atomic_dec_32(&cp->p_pool->pool_ref);
641 mutex_exit(&cp->p_lock);
642
643 orphpp = &p->p_orphan;
644 while (*orphpp != cp)
645 orphpp = &(*orphpp)->p_nextorph;
646 *orphpp = cp->p_nextorph;
647 if (p->p_child == cp)
648 p->p_child = cp->p_sibling;
649 if (cp->p_sibling)
650 cp->p_sibling->p_psibling = cp->p_psibling;
651 if (cp->p_psibling)
652 cp->p_psibling->p_sibling = cp->p_sibling;
653 pid_exit(cp, tk);
654 mutex_exit(&pidlock);
655
656 task_rele(tk);
657
658 mutex_enter(&p->p_lock);
659 pool_barrier_exit();
660 continuelwps(p);
661 mutex_exit(&p->p_lock);
662 error = EAGAIN;
663 forkerr:
664 return ((int64_t)set_errno(error));
665 }
666
667 /*
668 * Free allocated resources from getproc() if a fork failed.
669 */
670 static void
671 fork_fail(proc_t *cp)
672 {
673 uf_info_t *fip = P_FINFO(cp);
674
675 fcnt_add(fip, -1);
676 sigdelq(cp, NULL, 0);
677
678 mutex_enter(&pidlock);
679 upcount_dec(crgetruid(cp->p_cred), crgetzoneid(cp->p_cred));
680 mutex_exit(&pidlock);
681
682 /*
683 * single threaded, so no locking needed here
684 */
685 crfree(cp->p_cred);
686
687 kmem_free(fip->fi_list, fip->fi_nfiles * sizeof (uf_entry_t));
688
689 VN_RELE(PTOU(curproc)->u_cdir);
690 if (PTOU(curproc)->u_rdir)
691 VN_RELE(PTOU(curproc)->u_rdir);
692 if (cp->p_exec)
693 VN_RELE(cp->p_exec);
694 if (cp->p_execdir)
695 VN_RELE(cp->p_execdir);
696 if (PTOU(curproc)->u_cwd)
697 refstr_rele(PTOU(curproc)->u_cwd);
698 if (PROC_IS_BRANDED(cp)) {
699 brand_clearbrand(cp, B_TRUE);
700 }
701 }
702
703 /*
704 * Clean up the lwps already created for this child process.
705 * The fork failed while duplicating all the lwps of the parent
706 * and those lwps already created must be freed.
707 * This process is invisible to the rest of the system,
708 * so we don't need to hold p->p_lock to protect the list.
709 */
710 static void
711 forklwp_fail(proc_t *p)
712 {
713 kthread_t *t;
714 task_t *tk;
715 int branded = 0;
716
717 if (PROC_IS_BRANDED(p))
718 branded = 1;
719
720 while ((t = p->p_tlist) != NULL) {
721 /*
722 * First remove the lwp from the process's p_tlist.
723 */
724 if (t != t->t_forw)
725 p->p_tlist = t->t_forw;
726 else
727 p->p_tlist = NULL;
728 p->p_lwpcnt--;
729 t->t_forw->t_back = t->t_back;
730 t->t_back->t_forw = t->t_forw;
731
732 tk = p->p_task;
733 mutex_enter(&p->p_zone->zone_nlwps_lock);
734 tk->tk_nlwps--;
735 tk->tk_proj->kpj_nlwps--;
736 p->p_zone->zone_nlwps--;
737 mutex_exit(&p->p_zone->zone_nlwps_lock);
738
739 ASSERT(t->t_schedctl == NULL);
740
741 if (branded)
742 BROP(p)->b_freelwp(ttolwp(t));
743
744 if (t->t_door != NULL) {
745 kmem_free(t->t_door, sizeof (door_data_t));
746 t->t_door = NULL;
747 }
748 lwp_ctmpl_clear(ttolwp(t));
749
750 /*
751 * Remove the thread from the all threads list.
752 * We need to hold pidlock for this.
753 */
754 mutex_enter(&pidlock);
755 t->t_next->t_prev = t->t_prev;
756 t->t_prev->t_next = t->t_next;
757 CL_EXIT(t); /* tell the scheduler that we're exiting */
758 cv_broadcast(&t->t_joincv); /* tell anyone in thread_join */
759 mutex_exit(&pidlock);
760
761 /*
762 * Let the lgroup load averages know that this thread isn't
763 * going to show up (i.e. un-do what was done on behalf of
764 * this thread by the earlier lgrp_move_thread()).
765 */
766 kpreempt_disable();
767 lgrp_move_thread(t, NULL, 1);
768 kpreempt_enable();
769
770 /*
771 * The thread was created TS_STOPPED.
772 * We change it to TS_FREE to avoid an
773 * ASSERT() panic in thread_free().
774 */
775 t->t_state = TS_FREE;
776 thread_rele(t);
777 thread_free(t);
778 }
779 }
780
781 extern struct as kas;
782
783 /*
784 * fork a kernel process.
785 */
786 int
787 newproc(void (*pc)(), caddr_t arg, id_t cid, int pri, struct contract **ct,
788 pid_t pid)
789 {
790 proc_t *p;
791 struct user *up;
792 kthread_t *t;
793 cont_process_t *ctp = NULL;
794 rctl_entity_p_t e;
795
796 ASSERT(cid != sysdccid);
797 ASSERT(cid != syscid || ct == NULL);
798 if (CLASS_KERNEL(cid)) {
799 rctl_alloc_gp_t *init_gp;
800 rctl_set_t *init_set;
801
802 ASSERT(pid != 1);
803
804 if (getproc(&p, pid, GETPROC_KERNEL) < 0)
805 return (EAGAIN);
806
807 /*
808 * Release the hold on the p_exec and p_execdir, these
809 * were acquired in getproc()
810 */
811 if (p->p_execdir != NULL)
812 VN_RELE(p->p_execdir);
813 if (p->p_exec != NULL)
814 VN_RELE(p->p_exec);
815 p->p_flag |= SNOWAIT;
816 p->p_exec = NULL;
817 p->p_execdir = NULL;
818
819 init_set = rctl_set_create();
820 init_gp = rctl_set_init_prealloc(RCENTITY_PROCESS);
821
822 /*
823 * kernel processes do not inherit /proc tracing flags.
824 */
825 sigemptyset(&p->p_sigmask);
826 premptyset(&p->p_fltmask);
827 up = PTOU(p);
828 up->u_systrap = 0;
829 premptyset(&(up->u_entrymask));
830 premptyset(&(up->u_exitmask));
831 mutex_enter(&p->p_lock);
832 e.rcep_p.proc = p;
833 e.rcep_t = RCENTITY_PROCESS;
834 p->p_rctls = rctl_set_init(RCENTITY_PROCESS, p, &e, init_set,
835 init_gp);
836 mutex_exit(&p->p_lock);
837
838 rctl_prealloc_destroy(init_gp);
839
840 t = lwp_kernel_create(p, pc, arg, TS_STOPPED, pri);
841 } else {
842 rctl_alloc_gp_t *init_gp, *default_gp;
843 rctl_set_t *init_set;
844 task_t *tk, *tk_old;
845 klwp_t *lwp;
846
847 if (getproc(&p, pid, GETPROC_USER) < 0)
848 return (EAGAIN);
849 /*
850 * init creates a new task, distinct from the task
851 * containing kernel "processes".
852 */
853 tk = task_create(0, p->p_zone);
854 mutex_enter(&tk->tk_zone->zone_nlwps_lock);
855 tk->tk_proj->kpj_ntasks++;
856 tk->tk_nprocs++;
857 mutex_exit(&tk->tk_zone->zone_nlwps_lock);
858
859 default_gp = rctl_rlimit_set_prealloc(RLIM_NLIMITS);
860 init_gp = rctl_set_init_prealloc(RCENTITY_PROCESS);
861 init_set = rctl_set_create();
862
863 mutex_enter(&pidlock);
864 mutex_enter(&p->p_lock);
865 tk_old = p->p_task; /* switch to new task */
866
867 task_detach(p);
868 task_begin(tk, p);
869 mutex_exit(&pidlock);
870
871 mutex_enter(&tk_old->tk_zone->zone_nlwps_lock);
872 tk_old->tk_nprocs--;
873 mutex_exit(&tk_old->tk_zone->zone_nlwps_lock);
874
875 e.rcep_p.proc = p;
876 e.rcep_t = RCENTITY_PROCESS;
877 p->p_rctls = rctl_set_init(RCENTITY_PROCESS, p, &e, init_set,
878 init_gp);
879 rctlproc_default_init(p, default_gp);
880 mutex_exit(&p->p_lock);
881
882 task_rele(tk_old);
883 rctl_prealloc_destroy(default_gp);
884 rctl_prealloc_destroy(init_gp);
885
886 if ((lwp = lwp_create(pc, arg, 0, p, TS_STOPPED, pri,
887 &curthread->t_hold, cid, 1)) == NULL) {
888 task_t *tk;
889 fork_fail(p);
890 mutex_enter(&pidlock);
891 mutex_enter(&p->p_lock);
892 tk = p->p_task;
893 task_detach(p);
894 ASSERT(p->p_pool->pool_ref > 0);
895 atomic_add_32(&p->p_pool->pool_ref, -1);
896 mutex_exit(&p->p_lock);
897 pid_exit(p, tk);
898 mutex_exit(&pidlock);
899 task_rele(tk);
900
901 return (EAGAIN);
902 }
903 t = lwptot(lwp);
904
905 ctp = contract_process_fork(sys_process_tmpl, p, curproc,
906 B_FALSE);
907 ASSERT(ctp != NULL);
908 if (ct != NULL)
909 *ct = &ctp->conp_contract;
910 }
911
912 ASSERT3U(t->t_tid, ==, 1);
913 p->p_lwpid = 1;
914 mutex_enter(&pidlock);
915 pgjoin(p, p->p_parent->p_pgidp);
916 p->p_stat = SRUN;
917 mutex_enter(&p->p_lock);
918 t->t_proc_flag &= ~TP_HOLDLWP;
919 lwp_create_done(t);
920 mutex_exit(&p->p_lock);
921 mutex_exit(&pidlock);
922 return (0);
923 }
924
925 /*
926 * create a child proc struct.
927 */
928 static int
929 getproc(proc_t **cpp, pid_t pid, uint_t flags)
930 {
931 proc_t *pp, *cp;
932 pid_t newpid;
933 struct user *uarea;
934 extern uint_t nproc;
935 struct cred *cr;
936 uid_t ruid;
937 zoneid_t zoneid;
938 task_t *task;
939 kproject_t *proj;
940 zone_t *zone;
941 int rctlfail = 0;
942
943 if (zone_status_get(curproc->p_zone) >= ZONE_IS_SHUTTING_DOWN)
944 return (-1); /* no point in starting new processes */
945
946 pp = (flags & GETPROC_KERNEL) ? &p0 : curproc;
947 task = pp->p_task;
948 proj = task->tk_proj;
949 zone = pp->p_zone;
950
951 mutex_enter(&pp->p_lock);
952 mutex_enter(&zone->zone_nlwps_lock);
953 if (proj != proj0p) {
954 if (task->tk_nprocs >= task->tk_nprocs_ctl)
955 if (rctl_test(rc_task_nprocs, task->tk_rctls,
956 pp, 1, 0) & RCT_DENY)
957 rctlfail = 1;
958
959 if (proj->kpj_nprocs >= proj->kpj_nprocs_ctl)
960 if (rctl_test(rc_project_nprocs, proj->kpj_rctls,
961 pp, 1, 0) & RCT_DENY)
962 rctlfail = 1;
963
964 if (zone->zone_nprocs >= zone->zone_nprocs_ctl)
965 if (rctl_test(rc_zone_nprocs, zone->zone_rctls,
966 pp, 1, 0) & RCT_DENY)
967 rctlfail = 1;
968
969 if (rctlfail) {
970 mutex_exit(&zone->zone_nlwps_lock);
971 mutex_exit(&pp->p_lock);
972 atomic_inc_32(&zone->zone_ffcap);
973 goto punish;
974 }
975 }
976 task->tk_nprocs++;
977 proj->kpj_nprocs++;
978 zone->zone_nprocs++;
979 mutex_exit(&zone->zone_nlwps_lock);
980 mutex_exit(&pp->p_lock);
981
982 cp = kmem_cache_alloc(process_cache, KM_SLEEP);
983 bzero(cp, sizeof (proc_t));
984
985 /*
986 * Make proc entry for child process
987 */
988 mutex_init(&cp->p_splock, NULL, MUTEX_DEFAULT, NULL);
989 mutex_init(&cp->p_crlock, NULL, MUTEX_DEFAULT, NULL);
990 mutex_init(&cp->p_pflock, NULL, MUTEX_DEFAULT, NULL);
991 #if defined(__x86)
992 mutex_init(&cp->p_ldtlock, NULL, MUTEX_DEFAULT, NULL);
993 #endif
994 mutex_init(&cp->p_maplock, NULL, MUTEX_DEFAULT, NULL);
995 cp->p_stat = SIDL;
996 cp->p_mstart = gethrtime();
997 cp->p_as = &kas;
998 /*
999 * p_zone must be set before we call pid_allocate since the process
1000 * will be visible after that and code such as prfind_zone will
1001 * look at the p_zone field.
1002 */
1003 cp->p_zone = pp->p_zone;
1004 cp->p_t1_lgrpid = LGRP_NONE;
1005 cp->p_tr_lgrpid = LGRP_NONE;
1006
1007 if ((newpid = pid_allocate(cp, pid, PID_ALLOC_PROC)) == -1) {
1008 if (nproc == v.v_proc) {
1009 CPU_STATS_ADDQ(CPU, sys, procovf, 1);
1010 cmn_err(CE_WARN, "out of processes");
1011 }
1012 goto bad;
1013 }
1014
1015 mutex_enter(&pp->p_lock);
1016 cp->p_exec = pp->p_exec;
1017 cp->p_execdir = pp->p_execdir;
1018 mutex_exit(&pp->p_lock);
1019
1020 if (cp->p_exec) {
1021 VN_HOLD(cp->p_exec);
1022 /*
1023 * Each VOP_OPEN() must be paired with a corresponding
1024 * VOP_CLOSE(). In this case, the executable will be
1025 * closed for the child in either proc_exit() or gexec().
1026 */
1027 if (VOP_OPEN(&cp->p_exec, FREAD, CRED(), NULL) != 0) {
1028 VN_RELE(cp->p_exec);
1029 cp->p_exec = NULLVP;
1030 cp->p_execdir = NULLVP;
1031 goto bad;
1032 }
1033 }
1034 if (cp->p_execdir)
1035 VN_HOLD(cp->p_execdir);
1036
1037 /*
1038 * If not privileged make sure that this user hasn't exceeded
1039 * v.v_maxup processes, and that users collectively haven't
1040 * exceeded v.v_maxupttl processes.
1041 */
1042 mutex_enter(&pidlock);
1043 ASSERT(nproc < v.v_proc); /* otherwise how'd we get our pid? */
1044 cr = CRED();
1045 ruid = crgetruid(cr);
1046 zoneid = crgetzoneid(cr);
1047 if (nproc >= v.v_maxup && /* short-circuit; usually false */
1048 (nproc >= v.v_maxupttl ||
1049 upcount_get(ruid, zoneid) >= v.v_maxup) &&
1050 secpolicy_newproc(cr) != 0) {
1051 mutex_exit(&pidlock);
1052 zcmn_err(zoneid, CE_NOTE,
1053 "out of per-user processes for uid %d", ruid);
1054 goto bad;
1055 }
1056
1057 /*
1058 * Everything is cool, put the new proc on the active process list.
1059 * It is already on the pid list and in /proc.
1060 * Increment the per uid process count (upcount).
1061 */
1062 nproc++;
1063 upcount_inc(ruid, zoneid);
1064
1065 cp->p_next = practive;
1066 practive->p_prev = cp;
1067 practive = cp;
1068
1069 cp->p_ignore = pp->p_ignore;
1070 cp->p_siginfo = pp->p_siginfo;
1071 cp->p_flag = pp->p_flag & (SJCTL|SNOWAIT|SNOCD);
1072 cp->p_sessp = pp->p_sessp;
1073 sess_hold(pp);
1074 cp->p_brand = pp->p_brand;
1075 if (PROC_IS_BRANDED(pp))
1076 BROP(pp)->b_copy_procdata(cp, pp);
1077 cp->p_bssbase = pp->p_bssbase;
1078 cp->p_brkbase = pp->p_brkbase;
1079 cp->p_brksize = pp->p_brksize;
1080 cp->p_brkpageszc = pp->p_brkpageszc;
1081 cp->p_stksize = pp->p_stksize;
1082 cp->p_stkpageszc = pp->p_stkpageszc;
1083 cp->p_stkprot = pp->p_stkprot;
1084 cp->p_datprot = pp->p_datprot;
1085 cp->p_usrstack = pp->p_usrstack;
1086 cp->p_model = pp->p_model;
1087 cp->p_ppid = pp->p_pid;
1088 cp->p_ancpid = pp->p_pid;
1089 cp->p_portcnt = pp->p_portcnt;
1090 /*
1091 * Security flags are preserved on fork, the inherited copy come into
1092 * effect on exec
1093 */
1094 cp->p_secflags = pp->p_secflags;
1095
1096 /*
1097 * Initialize watchpoint structures
1098 */
1099 avl_create(&cp->p_warea, wa_compare, sizeof (struct watched_area),
1100 offsetof(struct watched_area, wa_link));
1101
1102 /*
1103 * Initialize immediate resource control values.
1104 */
1105 cp->p_stk_ctl = pp->p_stk_ctl;
1106 cp->p_fsz_ctl = pp->p_fsz_ctl;
1107 cp->p_vmem_ctl = pp->p_vmem_ctl;
1108 cp->p_fno_ctl = pp->p_fno_ctl;
1109
1110 /*
1111 * Link up to parent-child-sibling chain. No need to lock
1112 * in general since only a call to freeproc() (done by the
1113 * same parent as newproc()) diddles with the child chain.
1114 */
1115 cp->p_sibling = pp->p_child;
1116 if (pp->p_child)
1117 pp->p_child->p_psibling = cp;
1118
1119 cp->p_parent = pp;
1120 pp->p_child = cp;
1121
1122 cp->p_child_ns = NULL;
1123 cp->p_sibling_ns = NULL;
1124
1125 cp->p_nextorph = pp->p_orphan;
1126 cp->p_nextofkin = pp;
1127 pp->p_orphan = cp;
1128
1129 /*
1130 * Inherit profiling state; do not inherit REALPROF profiling state.
1131 */
1132 cp->p_prof = pp->p_prof;
1133 cp->p_rprof_cyclic = CYCLIC_NONE;
1134
1135 /*
1136 * Inherit pool pointer from the parent. Kernel processes are
1137 * always bound to the default pool.
1138 */
1139 mutex_enter(&pp->p_lock);
1140 if (flags & GETPROC_KERNEL) {
1141 cp->p_pool = pool_default;
1142 cp->p_flag |= SSYS;
1143 } else {
1144 cp->p_pool = pp->p_pool;
1145 }
1146 atomic_inc_32(&cp->p_pool->pool_ref);
1147 mutex_exit(&pp->p_lock);
1148
1149 /*
1150 * Add the child process to the current task. Kernel processes
1151 * are always attached to task0.
1152 */
1153 mutex_enter(&cp->p_lock);
1154 if (flags & GETPROC_KERNEL)
1155 task_attach(task0p, cp);
1156 else
1157 task_attach(pp->p_task, cp);
1158 mutex_exit(&cp->p_lock);
1159 mutex_exit(&pidlock);
1160
1161 avl_create(&cp->p_ct_held, contract_compar, sizeof (contract_t),
1162 offsetof(contract_t, ct_ctlist));
1163
1164 /*
1165 * Duplicate any audit information kept in the process table
1166 */
1167 if (audit_active) /* copy audit data to cp */
1168 audit_newproc(cp);
1169
1170 crhold(cp->p_cred = cr);
1171
1172 /*
1173 * Bump up the counts on the file structures pointed at by the
1174 * parent's file table since the child will point at them too.
1175 */
1176 fcnt_add(P_FINFO(pp), 1);
1177
1178 if (PTOU(pp)->u_cdir) {
1179 VN_HOLD(PTOU(pp)->u_cdir);
1180 } else {
1181 ASSERT(pp == &p0);
1182 /*
1183 * We must be at or before vfs_mountroot(); it will take care of
1184 * assigning our current directory.
1185 */
1186 }
1187 if (PTOU(pp)->u_rdir)
1188 VN_HOLD(PTOU(pp)->u_rdir);
1189 if (PTOU(pp)->u_cwd)
1190 refstr_hold(PTOU(pp)->u_cwd);
1191
1192 /*
1193 * copy the parent's uarea.
1194 */
1195 uarea = PTOU(cp);
1196 bcopy(PTOU(pp), uarea, sizeof (*uarea));
1197 flist_fork(P_FINFO(pp), P_FINFO(cp));
1198
1199 gethrestime(&uarea->u_start);
1200 uarea->u_ticks = ddi_get_lbolt();
1201 uarea->u_mem = rm_asrss(pp->p_as);
1202 uarea->u_acflag = AFORK;
1203
1204 /*
1205 * If inherit-on-fork, copy /proc tracing flags to child.
1206 */
1207 if ((pp->p_proc_flag & P_PR_FORK) != 0) {
1208 cp->p_proc_flag |= pp->p_proc_flag & (P_PR_TRACE|P_PR_FORK);
1209 cp->p_sigmask = pp->p_sigmask;
1210 cp->p_fltmask = pp->p_fltmask;
1211 } else {
1212 sigemptyset(&cp->p_sigmask);
1213 premptyset(&cp->p_fltmask);
1214 uarea->u_systrap = 0;
1215 premptyset(&uarea->u_entrymask);
1216 premptyset(&uarea->u_exitmask);
1217 }
1218 /*
1219 * If microstate accounting is being inherited, mark child
1220 */
1221 if ((pp->p_flag & SMSFORK) != 0)
1222 cp->p_flag |= pp->p_flag & (SMSFORK|SMSACCT);
1223
1224 /*
1225 * Inherit fixalignment flag from the parent
1226 */
1227 cp->p_fixalignment = pp->p_fixalignment;
1228
1229 *cpp = cp;
1230 return (0);
1231
1232 bad:
1233 ASSERT(MUTEX_NOT_HELD(&pidlock));
1234
1235 mutex_destroy(&cp->p_crlock);
1236 mutex_destroy(&cp->p_pflock);
1237 #if defined(__x86)
1238 mutex_destroy(&cp->p_ldtlock);
1239 #endif
1240 if (newpid != -1) {
1241 proc_entry_free(cp->p_pidp);
1242 (void) pid_rele(cp->p_pidp);
1243 }
1244 kmem_cache_free(process_cache, cp);
1245
1246 mutex_enter(&zone->zone_nlwps_lock);
1247 task->tk_nprocs--;
1248 proj->kpj_nprocs--;
1249 zone->zone_nprocs--;
1250 mutex_exit(&zone->zone_nlwps_lock);
1251 atomic_inc_32(&zone->zone_ffnoproc);
1252
1253 punish:
1254 /*
1255 * We most likely got into this situation because some process is
1256 * forking out of control. As punishment, put it to sleep for a
1257 * bit so it can't eat the machine alive. Sleep interval is chosen
1258 * to allow no more than one fork failure per cpu per clock tick
1259 * on average (yes, I just made this up). This has two desirable
1260 * properties: (1) it sets a constant limit on the fork failure
1261 * rate, and (2) the busier the system is, the harsher the penalty
1262 * for abusing it becomes.
1263 */
1264 INCR_COUNT(&fork_fail_pending, &pidlock);
1265 delay(fork_fail_pending / ncpus + 1);
1266 DECR_COUNT(&fork_fail_pending, &pidlock);
1267
1268 return (-1); /* out of memory or proc slots */
1269 }
1270
1271 /*
1272 * Release virtual memory.
1273 * In the case of vfork(), the child was given exclusive access to its
1274 * parent's address space. The parent is waiting in vfwait() for the
1275 * child to release its exclusive claim via relvm().
1276 */
1277 void
1278 relvm()
1279 {
1280 proc_t *p = curproc;
1281
1282 ASSERT((unsigned)p->p_lwpcnt <= 1);
1283
1284 prrelvm(); /* inform /proc */
1285
1286 if (p->p_flag & SVFORK) {
1287 proc_t *pp = p->p_parent;
1288 /*
1289 * The child process is either exec'ing or exit'ing.
1290 * The child is now separated from the parent's address
1291 * space. The parent process is made dispatchable.
1292 *
1293 * This is a delicate locking maneuver, involving
1294 * both the parent's p_lock and the child's p_lock.
1295 * As soon as the SVFORK flag is turned off, the
1296 * parent is free to run, but it must not run until
1297 * we wake it up using its p_cv because it might
1298 * exit and we would be referencing invalid memory.
1299 * Therefore, we hold the parent with its p_lock
1300 * while protecting our p_flags with our own p_lock.
1301 */
1302 try_again:
1303 mutex_enter(&p->p_lock); /* grab child's lock first */
1304 prbarrier(p); /* make sure /proc is blocked out */
1305 mutex_enter(&pp->p_lock);
1306
1307 /*
1308 * Check if parent is locked by /proc.
1309 */
1310 if (pp->p_proc_flag & P_PR_LOCK) {
1311 /*
1312 * Delay until /proc is done with the parent.
1313 * We must drop our (the child's) p->p_lock, wait
1314 * via prbarrier() on the parent, then start over.
1315 */
1316 mutex_exit(&p->p_lock);
1317 prbarrier(pp);
1318 mutex_exit(&pp->p_lock);
1319 goto try_again;
1320 }
1321 p->p_flag &= ~SVFORK;
1322 kpreempt_disable();
1323 p->p_as = &kas;
1324
1325 /*
1326 * notify hat of change in thread's address space
1327 */
1328 hat_thread_exit(curthread);
1329 kpreempt_enable();
1330
1331 /*
1332 * child sizes are copied back to parent because
1333 * child may have grown.
1334 */
1335 pp->p_brkbase = p->p_brkbase;
1336 pp->p_brksize = p->p_brksize;
1337 pp->p_stksize = p->p_stksize;
1338
1339 /*
1340 * Copy back the shm accounting information
1341 * to the parent process.
1342 */
1343 pp->p_segacct = p->p_segacct;
1344 p->p_segacct = NULL;
1345
1346 /*
1347 * The parent is no longer waiting for the vfork()d child.
1348 * Restore the parent's watched pages, if any. This is
1349 * safe because we know the parent is not locked by /proc
1350 */
1351 pp->p_flag &= ~SVFWAIT;
1352 if (avl_numnodes(&pp->p_wpage) != 0) {
1353 pp->p_as->a_wpage = pp->p_wpage;
1354 avl_create(&pp->p_wpage, wp_compare,
1355 sizeof (struct watched_page),
1356 offsetof(struct watched_page, wp_link));
1357 }
1358 cv_signal(&pp->p_cv);
1359 mutex_exit(&pp->p_lock);
1360 mutex_exit(&p->p_lock);
1361 } else {
1362 if (p->p_as != &kas) {
1363 struct as *as;
1364
1365 if (p->p_segacct)
1366 shmexit(p);
1367
1368 /*
1369 * We grab p_lock for the benefit of /proc
1370 */
1371 kpreempt_disable();
1372 mutex_enter(&p->p_lock);
1373 prbarrier(p); /* make sure /proc is blocked out */
1374 as = p->p_as;
1375 p->p_as = &kas;
1376 mutex_exit(&p->p_lock);
1377
1378 /*
1379 * notify hat of change in thread's address space
1380 */
1381 hat_thread_exit(curthread);
1382 kpreempt_enable();
1383
1384 as_free(as);
1385 p->p_tr_lgrpid = LGRP_NONE;
1386 }
1387 }
1388 }
1389
1390 /*
1391 * Wait for child to exec or exit.
1392 * Called by parent of vfork'ed process.
1393 * See important comments in relvm(), above.
1394 */
1395 void
1396 vfwait(pid_t pid)
1397 {
1398 int signalled = 0;
1399 proc_t *pp = ttoproc(curthread);
1400 proc_t *cp;
1401
1402 /*
1403 * Wait for child to exec or exit.
1404 */
1405 for (;;) {
1406 mutex_enter(&pidlock);
1407 cp = prfind(pid);
1408 if (cp == NULL || cp->p_parent != pp) {
1409 /*
1410 * Child has exit()ed.
1411 */
1412 mutex_exit(&pidlock);
1413 break;
1414 }
1415 /*
1416 * Grab the child's p_lock before releasing pidlock.
1417 * Otherwise, the child could exit and we would be
1418 * referencing invalid memory.
1419 */
1420 mutex_enter(&cp->p_lock);
1421 mutex_exit(&pidlock);
1422 if (!(cp->p_flag & SVFORK)) {
1423 /*
1424 * Child has exec()ed or is exit()ing.
1425 */
1426 mutex_exit(&cp->p_lock);
1427 break;
1428 }
1429 mutex_enter(&pp->p_lock);
1430 mutex_exit(&cp->p_lock);
1431 /*
1432 * We might be waked up spuriously from the cv_wait().
1433 * We have to do the whole operation over again to be
1434 * sure the child's SVFORK flag really is turned off.
1435 * We cannot make reference to the child because it can
1436 * exit before we return and we would be referencing
1437 * invalid memory.
1438 *
1439 * Because this is potentially a very long-term wait,
1440 * we call cv_wait_sig() (for its jobcontrol and /proc
1441 * side-effects) unless there is a current signal, in
1442 * which case we use cv_wait() because we cannot return
1443 * from this function until the child has released the
1444 * address space. Calling cv_wait_sig() with a current
1445 * signal would lead to an indefinite loop here because
1446 * cv_wait_sig() returns immediately in this case.
1447 */
1448 if (signalled)
1449 cv_wait(&pp->p_cv, &pp->p_lock);
1450 else
1451 signalled = !cv_wait_sig(&pp->p_cv, &pp->p_lock);
1452 mutex_exit(&pp->p_lock);
1453 }
1454
1455 /* restore watchpoints to parent */
1456 if (pr_watch_active(pp)) {
1457 struct as *as = pp->p_as;
1458 AS_LOCK_ENTER(as, RW_WRITER);
1459 as_setwatch(as);
1460 AS_LOCK_EXIT(as);
1461 }
1462
1463 mutex_enter(&pp->p_lock);
1464 prbarrier(pp); /* barrier against /proc locking */
1465 continuelwps(pp);
1466 mutex_exit(&pp->p_lock);
1467 }