1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_compat.h" 41 #include "opt_ktrace.h" 42 #include "opt_mac.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/sysproto.h> 47 #include <sys/eventhandler.h> 48 #include <sys/kernel.h> 49 #include <sys/malloc.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/proc.h> 53 #include <sys/pioctl.h> 54 #include <sys/tty.h> 55 #include <sys/wait.h> 56 #include <sys/vmmeter.h> 57 #include <sys/vnode.h> 58 #include <sys/resourcevar.h> 59 #include <sys/sbuf.h> 60 #include <sys/signalvar.h> 61 #include <sys/sched.h> 62 #include <sys/sx.h> 63 #include <sys/syscallsubr.h> 64 #include <sys/syslog.h> 65 #include <sys/ptrace.h> 66 #include <sys/acct.h> /* for acct_process() function prototype */ 67 #include <sys/filedesc.h> 68 #include <sys/mac.h> 69 #include <sys/shm.h> 70 #include <sys/sem.h> 71 #ifdef KTRACE 72 #include <sys/ktrace.h> 73 #endif 74 75 #include <security/audit/audit.h> 76 77 #include <vm/vm.h> 78 #include <vm/vm_extern.h> 79 #include <vm/vm_param.h> 80 #include <vm/pmap.h> 81 #include <vm/vm_map.h> 82 #include <vm/vm_page.h> 83 #include <vm/uma.h> 84 85 /* Required to be non-static for SysVR4 emulator */ 86 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 87 88 /* Hook for NFS teardown procedure. */ 89 void (*nlminfo_release_p)(struct proc *p); 90 91 /* 92 * exit -- 93 * Death of process. 94 * 95 * MPSAFE 96 */ 97 void 98 sys_exit(struct thread *td, struct sys_exit_args *uap) 99 { 100 101 exit1(td, W_EXITCODE(uap->rval, 0)); 102 /* NOTREACHED */ 103 } 104 105 /* 106 * Exit: deallocate address space and other resources, change proc state 107 * to zombie, and unlink proc from allproc and parent's lists. Save exit 108 * status and rusage for wait(). Check for child processes and orphan them. 109 */ 110 void 111 exit1(struct thread *td, int rv) 112 { 113 struct proc *p, *nq, *q; 114 struct tty *tp; 115 struct vnode *ttyvp; 116 struct vnode *vtmp; 117 #ifdef KTRACE 118 struct vnode *tracevp; 119 struct ucred *tracecred; 120 #endif 121 struct plimit *plim; 122 int locked; 123 124 /* 125 * Drop Giant if caller has it. Eventually we should warn about 126 * being called with Giant held. 127 */ 128 while (mtx_owned(&Giant)) 129 mtx_unlock(&Giant); 130 131 p = td->td_proc; 132 if (p == initproc) { 133 printf("init died (signal %d, exit %d)\n", 134 WTERMSIG(rv), WEXITSTATUS(rv)); 135 panic("Going nowhere without my init!"); 136 } 137 138 /* 139 * MUST abort all other threads before proceeding past here. 140 */ 141 PROC_LOCK(p); 142 if (p->p_flag & P_HADTHREADS) { 143 retry: 144 /* 145 * First check if some other thread got here before us.. 146 * if so, act apropriatly, (exit or suspend); 147 */ 148 thread_suspend_check(0); 149 150 /* 151 * Kill off the other threads. This requires 152 * some co-operation from other parts of the kernel 153 * so it may not be instantaneous. With this state set 154 * any thread entering the kernel from userspace will 155 * thread_exit() in trap(). Any thread attempting to 156 * sleep will return immediately with EINTR or EWOULDBLOCK 157 * which will hopefully force them to back out to userland 158 * freeing resources as they go. Any thread attempting 159 * to return to userland will thread_exit() from userret(). 160 * thread_exit() will unsuspend us when the last of the 161 * other threads exits. 162 * If there is already a thread singler after resumption, 163 * calling thread_single will fail; in that case, we just 164 * re-check all suspension request, the thread should 165 * either be suspended there or exit. 166 */ 167 if (thread_single(SINGLE_EXIT)) 168 goto retry; 169 170 /* 171 * All other activity in this process is now stopped. 172 * Threading support has been turned off. 173 */ 174 } 175 176 /* 177 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 178 * on our vmspace, so we should block below until they have 179 * released their reference to us. Note that if they have 180 * requested S_EXIT stops we will block here until they ack 181 * via PIOCCONT. 182 */ 183 _STOPEVENT(p, S_EXIT, rv); 184 185 /* 186 * Note that we are exiting and do another wakeup of anyone in 187 * PIOCWAIT in case they aren't listening for S_EXIT stops or 188 * decided to wait again after we told them we are exiting. 189 */ 190 p->p_flag |= P_WEXIT; 191 wakeup(&p->p_stype); 192 193 /* 194 * Wait for any processes that have a hold on our vmspace to 195 * release their reference. 196 */ 197 while (p->p_lock > 0) 198 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 199 200 PROC_LOCK(p->p_pptr); 201 sigqueue_take(p->p_ksi); 202 PROC_UNLOCK(p->p_pptr); 203 204 PROC_UNLOCK(p); 205 206 #ifdef AUDIT 207 /* 208 * The Sun BSM exit token contains two components: an exit status as 209 * passed to exit(), and a return value to indicate what sort of exit 210 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 211 * what the return value is. 212 */ 213 AUDIT_ARG(exit, WEXITSTATUS(rv), 0); 214 AUDIT_SYSCALL_EXIT(0, td); 215 #endif 216 217 /* Are we a task leader? */ 218 if (p == p->p_leader) { 219 mtx_lock(&ppeers_lock); 220 q = p->p_peers; 221 while (q != NULL) { 222 PROC_LOCK(q); 223 psignal(q, SIGKILL); 224 PROC_UNLOCK(q); 225 q = q->p_peers; 226 } 227 while (p->p_peers != NULL) 228 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 229 mtx_unlock(&ppeers_lock); 230 } 231 232 /* 233 * Check if any loadable modules need anything done at process exit. 234 * E.g. SYSV IPC stuff 235 * XXX what if one of these generates an error? 236 */ 237 EVENTHANDLER_INVOKE(process_exit, p); 238 239 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 240 M_ZOMBIE, M_WAITOK); 241 /* 242 * If parent is waiting for us to exit or exec, 243 * P_PPWAIT is set; we will wakeup the parent below. 244 */ 245 PROC_LOCK(p); 246 stopprofclock(p); 247 p->p_flag &= ~(P_TRACED | P_PPWAIT); 248 249 /* 250 * Stop the real interval timer. If the handler is currently 251 * executing, prevent it from rearming itself and let it finish. 252 */ 253 if (timevalisset(&p->p_realtimer.it_value) && 254 callout_stop(&p->p_itcallout) == 0) { 255 timevalclear(&p->p_realtimer.it_interval); 256 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 257 KASSERT(!timevalisset(&p->p_realtimer.it_value), 258 ("realtime timer is still armed")); 259 } 260 sigqueue_flush(&p->p_sigqueue); 261 sigqueue_flush(&td->td_sigqueue); 262 PROC_UNLOCK(p); 263 264 /* 265 * Reset any sigio structures pointing to us as a result of 266 * F_SETOWN with our pid. 267 */ 268 funsetownlst(&p->p_sigiolst); 269 270 /* 271 * If this process has an nlminfo data area (for lockd), release it 272 */ 273 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 274 (*nlminfo_release_p)(p); 275 276 /* 277 * Close open files and release open-file table. 278 * This may block! 279 */ 280 fdfree(td); 281 282 /* 283 * If this thread tickled GEOM, we need to wait for the giggling to 284 * stop before we return to userland 285 */ 286 if (td->td_pflags & TDP_GEOM) 287 g_waitidle(); 288 289 /* 290 * Remove ourself from our leader's peer list and wake our leader. 291 */ 292 mtx_lock(&ppeers_lock); 293 if (p->p_leader->p_peers) { 294 q = p->p_leader; 295 while (q->p_peers != p) 296 q = q->p_peers; 297 q->p_peers = p->p_peers; 298 wakeup(p->p_leader); 299 } 300 mtx_unlock(&ppeers_lock); 301 302 vmspace_exit(td); 303 304 sx_xlock(&proctree_lock); 305 if (SESS_LEADER(p)) { 306 struct session *sp; 307 308 sp = p->p_session; 309 if (sp->s_ttyvp) { 310 locked = VFS_LOCK_GIANT(sp->s_ttyvp->v_mount); 311 /* 312 * Controlling process. 313 * Signal foreground pgrp, 314 * drain controlling terminal 315 * and revoke access to controlling terminal. 316 */ 317 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 318 tp = sp->s_ttyp; 319 if (sp->s_ttyp->t_pgrp) { 320 PGRP_LOCK(sp->s_ttyp->t_pgrp); 321 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 322 PGRP_UNLOCK(sp->s_ttyp->t_pgrp); 323 } 324 /* XXX tp should be locked. */ 325 sx_xunlock(&proctree_lock); 326 (void) ttywait(tp); 327 sx_xlock(&proctree_lock); 328 /* 329 * The tty could have been revoked 330 * if we blocked. 331 */ 332 if (sp->s_ttyvp) { 333 ttyvp = sp->s_ttyvp; 334 SESS_LOCK(p->p_session); 335 sp->s_ttyvp = NULL; 336 SESS_UNLOCK(p->p_session); 337 sx_xunlock(&proctree_lock); 338 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td); 339 VOP_REVOKE(ttyvp, REVOKEALL); 340 vput(ttyvp); 341 sx_xlock(&proctree_lock); 342 } 343 } 344 if (sp->s_ttyvp) { 345 ttyvp = sp->s_ttyvp; 346 SESS_LOCK(p->p_session); 347 sp->s_ttyvp = NULL; 348 SESS_UNLOCK(p->p_session); 349 vrele(ttyvp); 350 } 351 /* 352 * s_ttyp is not zero'd; we use this to indicate 353 * that the session once had a controlling terminal. 354 * (for logging and informational purposes) 355 */ 356 VFS_UNLOCK_GIANT(locked); 357 } 358 SESS_LOCK(p->p_session); 359 sp->s_leader = NULL; 360 SESS_UNLOCK(p->p_session); 361 } 362 fixjobc(p, p->p_pgrp, 0); 363 sx_xunlock(&proctree_lock); 364 (void)acct_process(td); 365 #ifdef KTRACE 366 /* 367 * Drain any pending records on the thread and release the trace 368 * file. It might be better if drain-and-clear were atomic. 369 */ 370 ktrprocexit(td); 371 PROC_LOCK(p); 372 mtx_lock(&ktrace_mtx); 373 p->p_traceflag = 0; /* don't trace the vrele() */ 374 tracevp = p->p_tracevp; 375 p->p_tracevp = NULL; 376 tracecred = p->p_tracecred; 377 p->p_tracecred = NULL; 378 mtx_unlock(&ktrace_mtx); 379 PROC_UNLOCK(p); 380 if (tracevp != NULL) { 381 locked = VFS_LOCK_GIANT(tracevp->v_mount); 382 vrele(tracevp); 383 VFS_UNLOCK_GIANT(locked); 384 } 385 if (tracecred != NULL) 386 crfree(tracecred); 387 #endif 388 /* 389 * Release reference to text vnode 390 */ 391 if ((vtmp = p->p_textvp) != NULL) { 392 p->p_textvp = NULL; 393 locked = VFS_LOCK_GIANT(vtmp->v_mount); 394 vrele(vtmp); 395 VFS_UNLOCK_GIANT(locked); 396 } 397 398 /* 399 * Release our limits structure. 400 */ 401 PROC_LOCK(p); 402 plim = p->p_limit; 403 p->p_limit = NULL; 404 PROC_UNLOCK(p); 405 lim_free(plim); 406 407 /* 408 * Remove proc from allproc queue and pidhash chain. 409 * Place onto zombproc. Unlink from parent's child list. 410 */ 411 sx_xlock(&allproc_lock); 412 LIST_REMOVE(p, p_list); 413 LIST_INSERT_HEAD(&zombproc, p, p_list); 414 LIST_REMOVE(p, p_hash); 415 sx_xunlock(&allproc_lock); 416 417 /* 418 * Reparent all of our children to init. 419 */ 420 sx_xlock(&proctree_lock); 421 q = LIST_FIRST(&p->p_children); 422 if (q != NULL) /* only need this if any child is S_ZOMB */ 423 wakeup(initproc); 424 for (; q != NULL; q = nq) { 425 nq = LIST_NEXT(q, p_sibling); 426 PROC_LOCK(q); 427 proc_reparent(q, initproc); 428 q->p_sigparent = SIGCHLD; 429 /* 430 * Traced processes are killed 431 * since their existence means someone is screwing up. 432 */ 433 if (q->p_flag & P_TRACED) { 434 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 435 psignal(q, SIGKILL); 436 } 437 PROC_UNLOCK(q); 438 } 439 440 /* 441 * Save exit status and finalize rusage info except for times, 442 * adding in child rusage info later when our time is locked. 443 */ 444 PROC_LOCK(p); 445 p->p_xstat = rv; 446 p->p_xthread = td; 447 p->p_stats->p_ru.ru_nvcsw++; 448 *p->p_ru = p->p_stats->p_ru; 449 450 /* 451 * Notify interested parties of our demise. 452 */ 453 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 454 455 /* 456 * Just delete all entries in the p_klist. At this point we won't 457 * report any more events, and there are nasty race conditions that 458 * can beat us if we don't. 459 */ 460 knlist_clear(&p->p_klist, 1); 461 462 /* 463 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 464 * flag set, or if the handler is set to SIG_IGN, notify process 465 * 1 instead (and hope it will handle this situation). 466 */ 467 PROC_LOCK(p->p_pptr); 468 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 469 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 470 struct proc *pp; 471 472 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 473 pp = p->p_pptr; 474 PROC_UNLOCK(pp); 475 proc_reparent(p, initproc); 476 p->p_sigparent = SIGCHLD; 477 PROC_LOCK(p->p_pptr); 478 /* 479 * If this was the last child of our parent, notify 480 * parent, so in case he was wait(2)ing, he will 481 * continue. 482 */ 483 if (LIST_EMPTY(&pp->p_children)) 484 wakeup(pp); 485 } else 486 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 487 488 if (p->p_pptr == initproc) 489 psignal(p->p_pptr, SIGCHLD); 490 else if (p->p_sigparent != 0) { 491 if (p->p_sigparent == SIGCHLD) 492 childproc_exited(p); 493 else /* LINUX thread */ 494 psignal(p->p_pptr, p->p_sigparent); 495 } 496 PROC_UNLOCK(p->p_pptr); 497 PROC_UNLOCK(p); 498 499 /* 500 * Finally, call machine-dependent code to release the remaining 501 * resources including address space. 502 * The address space is released by "vmspace_exitfree(p)" in 503 * vm_waitproc(). 504 */ 505 cpu_exit(td); 506 507 WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object, 508 "process (pid %d) exiting", p->p_pid); 509 510 PROC_LOCK(p); 511 PROC_LOCK(p->p_pptr); 512 sx_xunlock(&proctree_lock); 513 514 /* 515 * We have to wait until after acquiring all locks before 516 * changing p_state. We need to avoid all possible context 517 * switches (including ones from blocking on a mutex) while 518 * marked as a zombie. We also have to set the zombie state 519 * before we release the parent process' proc lock to avoid 520 * a lost wakeup. So, we first call wakeup, then we grab the 521 * sched lock, update the state, and release the parent process' 522 * proc lock. 523 */ 524 wakeup(p->p_pptr); 525 mtx_lock_spin(&sched_lock); 526 p->p_state = PRS_ZOMBIE; 527 PROC_UNLOCK(p->p_pptr); 528 529 sched_exit(p->p_pptr, td); 530 531 /* 532 * Hopefully no one will try to deliver a signal to the process this 533 * late in the game. 534 */ 535 knlist_destroy(&p->p_klist); 536 537 /* 538 * Make sure the scheduler takes this thread out of its tables etc. 539 * This will also release this thread's reference to the ucred. 540 * Other thread parts to release include pcb bits and such. 541 */ 542 thread_exit(); 543 } 544 545 546 #ifndef _SYS_SYSPROTO_H_ 547 struct abort2_args { 548 char *why; 549 int nargs; 550 void **args; 551 }; 552 #endif 553 554 /* 555 * MPSAFE. 556 */ 557 int 558 abort2(struct thread *td, struct abort2_args *uap) 559 { 560 struct proc *p = td->td_proc; 561 struct sbuf *sb; 562 void *uargs[16]; 563 int error, i, sig; 564 565 error = 0; /* satisfy compiler */ 566 567 /* 568 * Do it right now so we can log either proper call of abort2(), or 569 * note, that invalid argument was passed. 512 is big enough to 570 * handle 16 arguments' descriptions with additional comments. 571 */ 572 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 573 sbuf_clear(sb); 574 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 575 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 576 /* 577 * Since we can't return from abort2(), send SIGKILL in cases, where 578 * abort2() was called improperly 579 */ 580 sig = SIGKILL; 581 /* Prevent from DoSes from user-space. */ 582 if (uap->nargs < 0 || uap->nargs > 16) 583 goto out; 584 if (uap->args == NULL) 585 goto out; 586 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 587 if (error != 0) 588 goto out; 589 /* 590 * Limit size of 'reason' string to 128. Will fit even when 591 * maximal number of arguments was chosen to be logged. 592 */ 593 if (uap->why != NULL) { 594 error = sbuf_copyin(sb, uap->why, 128); 595 if (error < 0) 596 goto out; 597 } else { 598 sbuf_printf(sb, "(null)"); 599 } 600 if (uap->nargs) { 601 sbuf_printf(sb, "("); 602 for (i = 0;i < uap->nargs; i++) 603 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 604 sbuf_printf(sb, ")"); 605 } 606 /* 607 * Final stage: arguments were proper, string has been 608 * successfully copied from userspace, and copying pointers 609 * from user-space succeed. 610 */ 611 sig = SIGABRT; 612 out: 613 if (sig == SIGKILL) { 614 sbuf_trim(sb); 615 sbuf_printf(sb, " (Reason text inaccessible)"); 616 } 617 sbuf_cat(sb, "\n"); 618 sbuf_finish(sb); 619 log(LOG_INFO, "%s", sbuf_data(sb)); 620 sbuf_delete(sb); 621 exit1(td, W_EXITCODE(0, sig)); 622 return (0); 623 } 624 625 626 #ifdef COMPAT_43 627 /* 628 * The dirty work is handled by kern_wait(). 629 * 630 * MPSAFE. 631 */ 632 int 633 owait(struct thread *td, struct owait_args *uap __unused) 634 { 635 int error, status; 636 637 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 638 if (error == 0) 639 td->td_retval[1] = status; 640 return (error); 641 } 642 #endif /* COMPAT_43 */ 643 644 /* 645 * The dirty work is handled by kern_wait(). 646 * 647 * MPSAFE. 648 */ 649 int 650 wait4(struct thread *td, struct wait_args *uap) 651 { 652 struct rusage ru, *rup; 653 int error, status; 654 655 if (uap->rusage != NULL) 656 rup = &ru; 657 else 658 rup = NULL; 659 error = kern_wait(td, uap->pid, &status, uap->options, rup); 660 if (uap->status != NULL && error == 0) 661 error = copyout(&status, uap->status, sizeof(status)); 662 if (uap->rusage != NULL && error == 0) 663 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 664 return (error); 665 } 666 667 int 668 kern_wait(struct thread *td, pid_t pid, int *status, int options, 669 struct rusage *rusage) 670 { 671 struct proc *p, *q, *t; 672 int error, nfound; 673 674 AUDIT_ARG(pid, pid); 675 676 q = td->td_proc; 677 if (pid == 0) { 678 PROC_LOCK(q); 679 pid = -q->p_pgid; 680 PROC_UNLOCK(q); 681 } 682 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 683 return (EINVAL); 684 loop: 685 if (q->p_flag & P_STATCHILD) { 686 PROC_LOCK(q); 687 q->p_flag &= ~P_STATCHILD; 688 PROC_UNLOCK(q); 689 } 690 nfound = 0; 691 sx_xlock(&proctree_lock); 692 LIST_FOREACH(p, &q->p_children, p_sibling) { 693 PROC_LOCK(p); 694 if (pid != WAIT_ANY && 695 p->p_pid != pid && p->p_pgid != -pid) { 696 PROC_UNLOCK(p); 697 continue; 698 } 699 if (p_canwait(td, p)) { 700 PROC_UNLOCK(p); 701 continue; 702 } 703 704 /* 705 * This special case handles a kthread spawned by linux_clone 706 * (see linux_misc.c). The linux_wait4 and linux_waitpid 707 * functions need to be able to distinguish between waiting 708 * on a process and waiting on a thread. It is a thread if 709 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 710 * signifies we want to wait for threads and not processes. 711 */ 712 if ((p->p_sigparent != SIGCHLD) ^ 713 ((options & WLINUXCLONE) != 0)) { 714 PROC_UNLOCK(p); 715 continue; 716 } 717 718 nfound++; 719 if (p->p_state == PRS_ZOMBIE) { 720 721 /* 722 * It is possible that the last thread of this 723 * process is still running on another CPU 724 * in thread_exit() after having dropped the process 725 * lock via PROC_UNLOCK() but before it has completed 726 * cpu_throw(). In that case, the other thread must 727 * still hold sched_lock, so simply by acquiring 728 * sched_lock once we will wait long enough for the 729 * thread to exit in that case. 730 */ 731 mtx_lock_spin(&sched_lock); 732 mtx_unlock_spin(&sched_lock); 733 734 td->td_retval[0] = p->p_pid; 735 if (status) 736 *status = p->p_xstat; /* convert to int */ 737 if (rusage) { 738 *rusage = *p->p_ru; 739 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 740 } 741 742 PROC_LOCK(q); 743 sigqueue_take(p->p_ksi); 744 PROC_UNLOCK(q); 745 746 /* 747 * If we got the child via a ptrace 'attach', 748 * we need to give it back to the old parent. 749 */ 750 PROC_UNLOCK(p); 751 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 752 PROC_LOCK(p); 753 p->p_oppid = 0; 754 proc_reparent(p, t); 755 PROC_UNLOCK(p); 756 tdsignal(t, NULL, SIGCHLD, p->p_ksi); 757 wakeup(t); 758 PROC_UNLOCK(t); 759 sx_xunlock(&proctree_lock); 760 return (0); 761 } 762 763 /* 764 * Remove other references to this process to ensure 765 * we have an exclusive reference. 766 */ 767 sx_xlock(&allproc_lock); 768 LIST_REMOVE(p, p_list); /* off zombproc */ 769 sx_xunlock(&allproc_lock); 770 LIST_REMOVE(p, p_sibling); 771 leavepgrp(p); 772 sx_xunlock(&proctree_lock); 773 774 /* 775 * As a side effect of this lock, we know that 776 * all other writes to this proc are visible now, so 777 * no more locking is needed for p. 778 */ 779 PROC_LOCK(p); 780 p->p_xstat = 0; /* XXX: why? */ 781 PROC_UNLOCK(p); 782 PROC_LOCK(q); 783 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru, 784 &p->p_rux); 785 PROC_UNLOCK(q); 786 FREE(p->p_ru, M_ZOMBIE); 787 p->p_ru = NULL; 788 789 /* 790 * Decrement the count of procs running with this uid. 791 */ 792 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 793 794 /* 795 * Free credentials, arguments, and sigacts. 796 */ 797 crfree(p->p_ucred); 798 p->p_ucred = NULL; 799 pargs_drop(p->p_args); 800 p->p_args = NULL; 801 sigacts_free(p->p_sigacts); 802 p->p_sigacts = NULL; 803 804 /* 805 * Do any thread-system specific cleanups. 806 */ 807 thread_wait(p); 808 809 /* 810 * Give vm and machine-dependent layer a chance 811 * to free anything that cpu_exit couldn't 812 * release while still running in process context. 813 */ 814 vm_waitproc(p); 815 #ifdef MAC 816 mac_destroy_proc(p); 817 #endif 818 #ifdef AUDIT 819 audit_proc_free(p); 820 #endif 821 KASSERT(FIRST_THREAD_IN_PROC(p), 822 ("kern_wait: no residual thread!")); 823 uma_zfree(proc_zone, p); 824 sx_xlock(&allproc_lock); 825 nprocs--; 826 sx_xunlock(&allproc_lock); 827 return (0); 828 } 829 mtx_lock_spin(&sched_lock); 830 if ((p->p_flag & P_STOPPED_SIG) && 831 (p->p_suspcount == p->p_numthreads) && 832 (p->p_flag & P_WAITED) == 0 && 833 (p->p_flag & P_TRACED || options & WUNTRACED)) { 834 mtx_unlock_spin(&sched_lock); 835 p->p_flag |= P_WAITED; 836 sx_xunlock(&proctree_lock); 837 td->td_retval[0] = p->p_pid; 838 if (status) 839 *status = W_STOPCODE(p->p_xstat); 840 PROC_UNLOCK(p); 841 842 PROC_LOCK(q); 843 sigqueue_take(p->p_ksi); 844 PROC_UNLOCK(q); 845 846 return (0); 847 } 848 mtx_unlock_spin(&sched_lock); 849 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 850 sx_xunlock(&proctree_lock); 851 td->td_retval[0] = p->p_pid; 852 p->p_flag &= ~P_CONTINUED; 853 PROC_UNLOCK(p); 854 855 PROC_LOCK(q); 856 sigqueue_take(p->p_ksi); 857 PROC_UNLOCK(q); 858 859 if (status) 860 *status = SIGCONT; 861 return (0); 862 } 863 PROC_UNLOCK(p); 864 } 865 if (nfound == 0) { 866 sx_xunlock(&proctree_lock); 867 return (ECHILD); 868 } 869 if (options & WNOHANG) { 870 sx_xunlock(&proctree_lock); 871 td->td_retval[0] = 0; 872 return (0); 873 } 874 PROC_LOCK(q); 875 sx_xunlock(&proctree_lock); 876 if (q->p_flag & P_STATCHILD) { 877 q->p_flag &= ~P_STATCHILD; 878 error = 0; 879 } else 880 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 881 PROC_UNLOCK(q); 882 if (error) 883 return (error); 884 goto loop; 885 } 886 887 /* 888 * Make process 'parent' the new parent of process 'child'. 889 * Must be called with an exclusive hold of proctree lock. 890 */ 891 void 892 proc_reparent(struct proc *child, struct proc *parent) 893 { 894 895 sx_assert(&proctree_lock, SX_XLOCKED); 896 PROC_LOCK_ASSERT(child, MA_OWNED); 897 if (child->p_pptr == parent) 898 return; 899 900 LIST_REMOVE(child, p_sibling); 901 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 902 child->p_pptr = parent; 903 } 904