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/shm.h> 69 #include <sys/sem.h> 70 #ifdef KTRACE 71 #include <sys/ktrace.h> 72 #endif 73 74 #include <security/audit/audit.h> 75 #include <security/mac/mac_framework.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_UNLOCK(p); 201 202 #ifdef AUDIT 203 /* 204 * The Sun BSM exit token contains two components: an exit status as 205 * passed to exit(), and a return value to indicate what sort of exit 206 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 207 * what the return value is. 208 */ 209 AUDIT_ARG(exit, WEXITSTATUS(rv), 0); 210 AUDIT_SYSCALL_EXIT(0, td); 211 #endif 212 213 /* Are we a task leader? */ 214 if (p == p->p_leader) { 215 mtx_lock(&ppeers_lock); 216 q = p->p_peers; 217 while (q != NULL) { 218 PROC_LOCK(q); 219 psignal(q, SIGKILL); 220 PROC_UNLOCK(q); 221 q = q->p_peers; 222 } 223 while (p->p_peers != NULL) 224 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 225 mtx_unlock(&ppeers_lock); 226 } 227 228 /* 229 * Check if any loadable modules need anything done at process exit. 230 * E.g. SYSV IPC stuff 231 * XXX what if one of these generates an error? 232 */ 233 EVENTHANDLER_INVOKE(process_exit, p); 234 235 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 236 M_ZOMBIE, M_WAITOK); 237 /* 238 * If parent is waiting for us to exit or exec, 239 * P_PPWAIT is set; we will wakeup the parent below. 240 */ 241 PROC_LOCK(p); 242 stopprofclock(p); 243 p->p_flag &= ~(P_TRACED | P_PPWAIT); 244 245 /* 246 * Stop the real interval timer. If the handler is currently 247 * executing, prevent it from rearming itself and let it finish. 248 */ 249 if (timevalisset(&p->p_realtimer.it_value) && 250 callout_stop(&p->p_itcallout) == 0) { 251 timevalclear(&p->p_realtimer.it_interval); 252 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 253 KASSERT(!timevalisset(&p->p_realtimer.it_value), 254 ("realtime timer is still armed")); 255 } 256 PROC_UNLOCK(p); 257 258 /* 259 * Reset any sigio structures pointing to us as a result of 260 * F_SETOWN with our pid. 261 */ 262 funsetownlst(&p->p_sigiolst); 263 264 /* 265 * If this process has an nlminfo data area (for lockd), release it 266 */ 267 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 268 (*nlminfo_release_p)(p); 269 270 /* 271 * Close open files and release open-file table. 272 * This may block! 273 */ 274 fdfree(td); 275 276 /* 277 * If this thread tickled GEOM, we need to wait for the giggling to 278 * stop before we return to userland 279 */ 280 if (td->td_pflags & TDP_GEOM) 281 g_waitidle(); 282 283 /* 284 * Remove ourself from our leader's peer list and wake our leader. 285 */ 286 mtx_lock(&ppeers_lock); 287 if (p->p_leader->p_peers) { 288 q = p->p_leader; 289 while (q->p_peers != p) 290 q = q->p_peers; 291 q->p_peers = p->p_peers; 292 wakeup(p->p_leader); 293 } 294 mtx_unlock(&ppeers_lock); 295 296 vmspace_exit(td); 297 298 mtx_lock(&Giant); /* XXX TTY */ 299 sx_xlock(&proctree_lock); 300 if (SESS_LEADER(p)) { 301 struct session *sp; 302 303 sp = p->p_session; 304 if (sp->s_ttyvp) { 305 /* 306 * Controlling process. 307 * Signal foreground pgrp, 308 * drain controlling terminal 309 * and revoke access to controlling terminal. 310 */ 311 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 312 tp = sp->s_ttyp; 313 if (sp->s_ttyp->t_pgrp) { 314 PGRP_LOCK(sp->s_ttyp->t_pgrp); 315 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 316 PGRP_UNLOCK(sp->s_ttyp->t_pgrp); 317 } 318 /* XXX tp should be locked. */ 319 sx_xunlock(&proctree_lock); 320 (void) ttywait(tp); 321 sx_xlock(&proctree_lock); 322 /* 323 * The tty could have been revoked 324 * if we blocked. 325 */ 326 if (sp->s_ttyvp) { 327 ttyvp = sp->s_ttyvp; 328 SESS_LOCK(p->p_session); 329 sp->s_ttyvp = NULL; 330 SESS_UNLOCK(p->p_session); 331 sx_xunlock(&proctree_lock); 332 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td); 333 VOP_REVOKE(ttyvp, REVOKEALL); 334 vput(ttyvp); 335 sx_xlock(&proctree_lock); 336 } 337 } 338 if (sp->s_ttyvp) { 339 ttyvp = sp->s_ttyvp; 340 SESS_LOCK(p->p_session); 341 sp->s_ttyvp = NULL; 342 SESS_UNLOCK(p->p_session); 343 vrele(ttyvp); 344 } 345 /* 346 * s_ttyp is not zero'd; we use this to indicate 347 * that the session once had a controlling terminal. 348 * (for logging and informational purposes) 349 */ 350 } 351 SESS_LOCK(p->p_session); 352 sp->s_leader = NULL; 353 SESS_UNLOCK(p->p_session); 354 } 355 fixjobc(p, p->p_pgrp, 0); 356 sx_xunlock(&proctree_lock); 357 (void)acct_process(td); 358 mtx_unlock(&Giant); 359 #ifdef KTRACE 360 /* 361 * Drain any pending records on the thread and release the trace 362 * file. It might be better if drain-and-clear were atomic. 363 */ 364 ktrprocexit(td); 365 PROC_LOCK(p); 366 mtx_lock(&ktrace_mtx); 367 p->p_traceflag = 0; /* don't trace the vrele() */ 368 tracevp = p->p_tracevp; 369 p->p_tracevp = NULL; 370 tracecred = p->p_tracecred; 371 p->p_tracecred = NULL; 372 mtx_unlock(&ktrace_mtx); 373 PROC_UNLOCK(p); 374 if (tracevp != NULL) { 375 locked = VFS_LOCK_GIANT(tracevp->v_mount); 376 vrele(tracevp); 377 VFS_UNLOCK_GIANT(locked); 378 } 379 if (tracecred != NULL) 380 crfree(tracecred); 381 #endif 382 /* 383 * Release reference to text vnode 384 */ 385 if ((vtmp = p->p_textvp) != NULL) { 386 p->p_textvp = NULL; 387 locked = VFS_LOCK_GIANT(vtmp->v_mount); 388 vrele(vtmp); 389 VFS_UNLOCK_GIANT(locked); 390 } 391 392 /* 393 * Release our limits structure. 394 */ 395 PROC_LOCK(p); 396 plim = p->p_limit; 397 p->p_limit = NULL; 398 PROC_UNLOCK(p); 399 lim_free(plim); 400 401 /* 402 * Remove proc from allproc queue and pidhash chain. 403 * Place onto zombproc. Unlink from parent's child list. 404 */ 405 sx_xlock(&allproc_lock); 406 LIST_REMOVE(p, p_list); 407 LIST_INSERT_HEAD(&zombproc, p, p_list); 408 LIST_REMOVE(p, p_hash); 409 sx_xunlock(&allproc_lock); 410 411 /* 412 * Reparent all of our children to init. 413 */ 414 sx_xlock(&proctree_lock); 415 q = LIST_FIRST(&p->p_children); 416 if (q != NULL) /* only need this if any child is S_ZOMB */ 417 wakeup(initproc); 418 for (; q != NULL; q = nq) { 419 nq = LIST_NEXT(q, p_sibling); 420 PROC_LOCK(q); 421 proc_reparent(q, initproc); 422 q->p_sigparent = SIGCHLD; 423 /* 424 * Traced processes are killed 425 * since their existence means someone is screwing up. 426 */ 427 if (q->p_flag & P_TRACED) { 428 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 429 psignal(q, SIGKILL); 430 } 431 PROC_UNLOCK(q); 432 } 433 434 /* 435 * Save exit status and finalize rusage info except for times, 436 * adding in child rusage info later when our time is locked. 437 */ 438 PROC_LOCK(p); 439 p->p_xstat = rv; 440 p->p_xthread = td; 441 p->p_stats->p_ru.ru_nvcsw++; 442 *p->p_ru = p->p_stats->p_ru; 443 444 /* 445 * Notify interested parties of our demise. 446 */ 447 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 448 449 /* 450 * Just delete all entries in the p_klist. At this point we won't 451 * report any more events, and there are nasty race conditions that 452 * can beat us if we don't. 453 */ 454 knlist_clear(&p->p_klist, 1); 455 456 /* 457 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 458 * flag set, or if the handler is set to SIG_IGN, notify process 459 * 1 instead (and hope it will handle this situation). 460 */ 461 PROC_LOCK(p->p_pptr); 462 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 463 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 464 struct proc *pp; 465 466 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 467 pp = p->p_pptr; 468 PROC_UNLOCK(pp); 469 proc_reparent(p, initproc); 470 p->p_sigparent = SIGCHLD; 471 PROC_LOCK(p->p_pptr); 472 /* 473 * If this was the last child of our parent, notify 474 * parent, so in case he was wait(2)ing, he will 475 * continue. 476 */ 477 if (LIST_EMPTY(&pp->p_children)) 478 wakeup(pp); 479 } else 480 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 481 482 if (p->p_pptr == initproc) 483 psignal(p->p_pptr, SIGCHLD); 484 else if (p->p_sigparent != 0) { 485 if (p->p_sigparent == SIGCHLD) 486 childproc_exited(p); 487 else /* LINUX thread */ 488 psignal(p->p_pptr, p->p_sigparent); 489 } 490 PROC_UNLOCK(p->p_pptr); 491 PROC_UNLOCK(p); 492 493 /* 494 * Finally, call machine-dependent code to release the remaining 495 * resources including address space. 496 * The address space is released by "vmspace_exitfree(p)" in 497 * vm_waitproc(). 498 */ 499 cpu_exit(td); 500 501 WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object, 502 "process (pid %d) exiting", p->p_pid); 503 504 PROC_LOCK(p); 505 PROC_LOCK(p->p_pptr); 506 sx_xunlock(&proctree_lock); 507 508 /* 509 * The state PRS_ZOMBIE prevents other proesses from sending 510 * signal to the process, to avoid memory leak, we free memory 511 * for signal queue at the time when the state is set. 512 */ 513 sigqueue_flush(&p->p_sigqueue); 514 sigqueue_flush(&td->td_sigqueue); 515 516 /* 517 * We have to wait until after acquiring all locks before 518 * changing p_state. We need to avoid all possible context 519 * switches (including ones from blocking on a mutex) while 520 * marked as a zombie. We also have to set the zombie state 521 * before we release the parent process' proc lock to avoid 522 * a lost wakeup. So, we first call wakeup, then we grab the 523 * sched lock, update the state, and release the parent process' 524 * proc lock. 525 */ 526 wakeup(p->p_pptr); 527 mtx_lock_spin(&sched_lock); 528 p->p_state = PRS_ZOMBIE; 529 PROC_UNLOCK(p->p_pptr); 530 531 sched_exit(p->p_pptr, td); 532 533 /* 534 * Hopefully no one will try to deliver a signal to the process this 535 * late in the game. 536 */ 537 knlist_destroy(&p->p_klist); 538 539 /* 540 * Make sure the scheduler takes this thread out of its tables etc. 541 * This will also release this thread's reference to the ucred. 542 * Other thread parts to release include pcb bits and such. 543 */ 544 thread_exit(); 545 } 546 547 548 #ifndef _SYS_SYSPROTO_H_ 549 struct abort2_args { 550 char *why; 551 int nargs; 552 void **args; 553 }; 554 #endif 555 556 /* 557 * MPSAFE. 558 */ 559 int 560 abort2(struct thread *td, struct abort2_args *uap) 561 { 562 struct proc *p = td->td_proc; 563 struct sbuf *sb; 564 void *uargs[16]; 565 int error, i, sig; 566 567 error = 0; /* satisfy compiler */ 568 569 /* 570 * Do it right now so we can log either proper call of abort2(), or 571 * note, that invalid argument was passed. 512 is big enough to 572 * handle 16 arguments' descriptions with additional comments. 573 */ 574 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 575 sbuf_clear(sb); 576 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 577 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 578 /* 579 * Since we can't return from abort2(), send SIGKILL in cases, where 580 * abort2() was called improperly 581 */ 582 sig = SIGKILL; 583 /* Prevent from DoSes from user-space. */ 584 if (uap->nargs < 0 || uap->nargs > 16) 585 goto out; 586 if (uap->args == NULL) 587 goto out; 588 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 589 if (error != 0) 590 goto out; 591 /* 592 * Limit size of 'reason' string to 128. Will fit even when 593 * maximal number of arguments was chosen to be logged. 594 */ 595 if (uap->why != NULL) { 596 error = sbuf_copyin(sb, uap->why, 128); 597 if (error < 0) 598 goto out; 599 } else { 600 sbuf_printf(sb, "(null)"); 601 } 602 if (uap->nargs) { 603 sbuf_printf(sb, "("); 604 for (i = 0;i < uap->nargs; i++) 605 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 606 sbuf_printf(sb, ")"); 607 } 608 /* 609 * Final stage: arguments were proper, string has been 610 * successfully copied from userspace, and copying pointers 611 * from user-space succeed. 612 */ 613 sig = SIGABRT; 614 out: 615 if (sig == SIGKILL) { 616 sbuf_trim(sb); 617 sbuf_printf(sb, " (Reason text inaccessible)"); 618 } 619 sbuf_cat(sb, "\n"); 620 sbuf_finish(sb); 621 log(LOG_INFO, "%s", sbuf_data(sb)); 622 sbuf_delete(sb); 623 exit1(td, W_EXITCODE(0, sig)); 624 return (0); 625 } 626 627 628 #ifdef COMPAT_43 629 /* 630 * The dirty work is handled by kern_wait(). 631 * 632 * MPSAFE. 633 */ 634 int 635 owait(struct thread *td, struct owait_args *uap __unused) 636 { 637 int error, status; 638 639 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 640 if (error == 0) 641 td->td_retval[1] = status; 642 return (error); 643 } 644 #endif /* COMPAT_43 */ 645 646 /* 647 * The dirty work is handled by kern_wait(). 648 * 649 * MPSAFE. 650 */ 651 int 652 wait4(struct thread *td, struct wait_args *uap) 653 { 654 struct rusage ru, *rup; 655 int error, status; 656 657 if (uap->rusage != NULL) 658 rup = &ru; 659 else 660 rup = NULL; 661 error = kern_wait(td, uap->pid, &status, uap->options, rup); 662 if (uap->status != NULL && error == 0) 663 error = copyout(&status, uap->status, sizeof(status)); 664 if (uap->rusage != NULL && error == 0) 665 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 666 return (error); 667 } 668 669 int 670 kern_wait(struct thread *td, pid_t pid, int *status, int options, 671 struct rusage *rusage) 672 { 673 struct proc *p, *q, *t; 674 int error, nfound; 675 676 AUDIT_ARG(pid, pid); 677 678 q = td->td_proc; 679 if (pid == 0) { 680 PROC_LOCK(q); 681 pid = -q->p_pgid; 682 PROC_UNLOCK(q); 683 } 684 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 685 return (EINVAL); 686 loop: 687 if (q->p_flag & P_STATCHILD) { 688 PROC_LOCK(q); 689 q->p_flag &= ~P_STATCHILD; 690 PROC_UNLOCK(q); 691 } 692 nfound = 0; 693 sx_xlock(&proctree_lock); 694 LIST_FOREACH(p, &q->p_children, p_sibling) { 695 PROC_LOCK(p); 696 if (pid != WAIT_ANY && 697 p->p_pid != pid && p->p_pgid != -pid) { 698 PROC_UNLOCK(p); 699 continue; 700 } 701 if (p_canwait(td, p)) { 702 PROC_UNLOCK(p); 703 continue; 704 } 705 706 /* 707 * This special case handles a kthread spawned by linux_clone 708 * (see linux_misc.c). The linux_wait4 and linux_waitpid 709 * functions need to be able to distinguish between waiting 710 * on a process and waiting on a thread. It is a thread if 711 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 712 * signifies we want to wait for threads and not processes. 713 */ 714 if ((p->p_sigparent != SIGCHLD) ^ 715 ((options & WLINUXCLONE) != 0)) { 716 PROC_UNLOCK(p); 717 continue; 718 } 719 720 nfound++; 721 if (p->p_state == PRS_ZOMBIE) { 722 723 /* 724 * It is possible that the last thread of this 725 * process is still running on another CPU 726 * in thread_exit() after having dropped the process 727 * lock via PROC_UNLOCK() but before it has completed 728 * cpu_throw(). In that case, the other thread must 729 * still hold sched_lock, so simply by acquiring 730 * sched_lock once we will wait long enough for the 731 * thread to exit in that case. 732 */ 733 mtx_lock_spin(&sched_lock); 734 mtx_unlock_spin(&sched_lock); 735 736 td->td_retval[0] = p->p_pid; 737 if (status) 738 *status = p->p_xstat; /* convert to int */ 739 if (rusage) { 740 *rusage = *p->p_ru; 741 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 742 } 743 744 PROC_LOCK(q); 745 sigqueue_take(p->p_ksi); 746 PROC_UNLOCK(q); 747 748 /* 749 * If we got the child via a ptrace 'attach', 750 * we need to give it back to the old parent. 751 */ 752 PROC_UNLOCK(p); 753 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 754 PROC_LOCK(p); 755 p->p_oppid = 0; 756 proc_reparent(p, t); 757 PROC_UNLOCK(p); 758 tdsignal(t, NULL, SIGCHLD, p->p_ksi); 759 wakeup(t); 760 PROC_UNLOCK(t); 761 sx_xunlock(&proctree_lock); 762 return (0); 763 } 764 765 /* 766 * Remove other references to this process to ensure 767 * we have an exclusive reference. 768 */ 769 sx_xlock(&allproc_lock); 770 LIST_REMOVE(p, p_list); /* off zombproc */ 771 sx_xunlock(&allproc_lock); 772 LIST_REMOVE(p, p_sibling); 773 leavepgrp(p); 774 sx_xunlock(&proctree_lock); 775 776 /* 777 * As a side effect of this lock, we know that 778 * all other writes to this proc are visible now, so 779 * no more locking is needed for p. 780 */ 781 PROC_LOCK(p); 782 p->p_xstat = 0; /* XXX: why? */ 783 PROC_UNLOCK(p); 784 PROC_LOCK(q); 785 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru, 786 &p->p_rux); 787 PROC_UNLOCK(q); 788 FREE(p->p_ru, M_ZOMBIE); 789 p->p_ru = NULL; 790 791 /* 792 * Decrement the count of procs running with this uid. 793 */ 794 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 795 796 /* 797 * Free credentials, arguments, and sigacts. 798 */ 799 crfree(p->p_ucred); 800 p->p_ucred = NULL; 801 pargs_drop(p->p_args); 802 p->p_args = NULL; 803 sigacts_free(p->p_sigacts); 804 p->p_sigacts = NULL; 805 806 /* 807 * Do any thread-system specific cleanups. 808 */ 809 thread_wait(p); 810 811 /* 812 * Give vm and machine-dependent layer a chance 813 * to free anything that cpu_exit couldn't 814 * release while still running in process context. 815 */ 816 vm_waitproc(p); 817 #ifdef MAC 818 mac_destroy_proc(p); 819 #endif 820 #ifdef AUDIT 821 audit_proc_free(p); 822 #endif 823 KASSERT(FIRST_THREAD_IN_PROC(p), 824 ("kern_wait: no residual thread!")); 825 uma_zfree(proc_zone, p); 826 sx_xlock(&allproc_lock); 827 nprocs--; 828 sx_xunlock(&allproc_lock); 829 return (0); 830 } 831 mtx_lock_spin(&sched_lock); 832 if ((p->p_flag & P_STOPPED_SIG) && 833 (p->p_suspcount == p->p_numthreads) && 834 (p->p_flag & P_WAITED) == 0 && 835 (p->p_flag & P_TRACED || options & WUNTRACED)) { 836 mtx_unlock_spin(&sched_lock); 837 p->p_flag |= P_WAITED; 838 sx_xunlock(&proctree_lock); 839 td->td_retval[0] = p->p_pid; 840 if (status) 841 *status = W_STOPCODE(p->p_xstat); 842 843 PROC_LOCK(q); 844 sigqueue_take(p->p_ksi); 845 PROC_UNLOCK(q); 846 PROC_UNLOCK(p); 847 848 return (0); 849 } 850 mtx_unlock_spin(&sched_lock); 851 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 852 sx_xunlock(&proctree_lock); 853 td->td_retval[0] = p->p_pid; 854 p->p_flag &= ~P_CONTINUED; 855 856 PROC_LOCK(q); 857 sigqueue_take(p->p_ksi); 858 PROC_UNLOCK(q); 859 PROC_UNLOCK(p); 860 861 if (status) 862 *status = SIGCONT; 863 return (0); 864 } 865 PROC_UNLOCK(p); 866 } 867 if (nfound == 0) { 868 sx_xunlock(&proctree_lock); 869 return (ECHILD); 870 } 871 if (options & WNOHANG) { 872 sx_xunlock(&proctree_lock); 873 td->td_retval[0] = 0; 874 return (0); 875 } 876 PROC_LOCK(q); 877 sx_xunlock(&proctree_lock); 878 if (q->p_flag & P_STATCHILD) { 879 q->p_flag &= ~P_STATCHILD; 880 error = 0; 881 } else 882 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 883 PROC_UNLOCK(q); 884 if (error) 885 return (error); 886 goto loop; 887 } 888 889 /* 890 * Make process 'parent' the new parent of process 'child'. 891 * Must be called with an exclusive hold of proctree lock. 892 */ 893 void 894 proc_reparent(struct proc *child, struct proc *parent) 895 { 896 897 sx_assert(&proctree_lock, SX_XLOCKED); 898 PROC_LOCK_ASSERT(child, MA_OWNED); 899 if (child->p_pptr == parent) 900 return; 901 902 PROC_LOCK(child->p_pptr); 903 sigqueue_take(child->p_ksi); 904 PROC_UNLOCK(child->p_pptr); 905 LIST_REMOVE(child, p_sibling); 906 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 907 child->p_pptr = parent; 908 } 909