kern_exit.c revision 151695
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: head/sys/kern/kern_exit.c 151695 2005-10-26 07:18:37Z glebius $"); 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/signalvar.h> 60#include <sys/sched.h> 61#include <sys/sx.h> 62#include <sys/syscallsubr.h> 63#include <sys/ptrace.h> 64#include <sys/acct.h> /* for acct_process() function prototype */ 65#include <sys/filedesc.h> 66#include <sys/mac.h> 67#include <sys/shm.h> 68#include <sys/sem.h> 69#include <sys/timers.h> 70#ifdef KTRACE 71#include <sys/ktrace.h> 72#endif 73 74#include <vm/vm.h> 75#include <vm/vm_extern.h> 76#include <vm/vm_param.h> 77#include <vm/pmap.h> 78#include <vm/vm_map.h> 79#include <vm/vm_page.h> 80#include <vm/uma.h> 81 82/* Required to be non-static for SysVR4 emulator */ 83MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 84 85/* Hook for NFS teardown procedure. */ 86void (*nlminfo_release_p)(struct proc *p); 87 88/* 89 * exit -- 90 * Death of process. 91 * 92 * MPSAFE 93 */ 94void 95sys_exit(struct thread *td, struct sys_exit_args *uap) 96{ 97 98 exit1(td, W_EXITCODE(uap->rval, 0)); 99 /* NOTREACHED */ 100} 101 102/* 103 * Exit: deallocate address space and other resources, change proc state 104 * to zombie, and unlink proc from allproc and parent's lists. Save exit 105 * status and rusage for wait(). Check for child processes and orphan them. 106 */ 107void 108exit1(struct thread *td, int rv) 109{ 110 struct bintime new_switchtime; 111 struct proc *p, *nq, *q; 112 struct tty *tp; 113 struct vnode *ttyvp; 114 struct vmspace *vm; 115 struct vnode *vtmp; 116#ifdef KTRACE 117 struct vnode *tracevp; 118 struct ucred *tracecred; 119#endif 120 struct plimit *plim; 121 int refcnt; 122 123 /* 124 * Drop Giant if caller has it. Eventually we should warn about 125 * being called with Giant held. 126 */ 127 while (mtx_owned(&Giant)) 128 mtx_unlock(&Giant); 129 130 p = td->td_proc; 131 if (p == initproc) { 132 printf("init died (signal %d, exit %d)\n", 133 WTERMSIG(rv), WEXITSTATUS(rv)); 134 panic("Going nowhere without my init!"); 135 } 136 137 /* 138 * MUST abort all other threads before proceeding past here. 139 */ 140 PROC_LOCK(p); 141 if (p->p_flag & P_HADTHREADS) { 142retry: 143 /* 144 * First check if some other thread got here before us.. 145 * if so, act apropriatly, (exit or suspend); 146 */ 147 thread_suspend_check(0); 148 149 /* 150 * Kill off the other threads. This requires 151 * some co-operation from other parts of the kernel 152 * so it may not be instantaneous. With this state set 153 * any thread entering the kernel from userspace will 154 * thread_exit() in trap(). Any thread attempting to 155 * sleep will return immediately with EINTR or EWOULDBLOCK 156 * which will hopefully force them to back out to userland 157 * freeing resources as they go. Any thread attempting 158 * to return to userland will thread_exit() from userret(). 159 * thread_exit() will unsuspend us when the last of the 160 * other threads exits. 161 * If there is already a thread singler after resumption, 162 * calling thread_single will fail; in that case, we just 163 * re-check all suspension request, the thread should 164 * either be suspended there or exit. 165 */ 166 if (thread_single(SINGLE_EXIT)) 167 goto retry; 168 169 /* 170 * All other activity in this process is now stopped. 171 * Threading support has been turned off. 172 */ 173 } 174 175 p->p_flag |= P_WEXIT; 176 PROC_UNLOCK(p); 177 178 /* Are we a task leader? */ 179 if (p == p->p_leader) { 180 mtx_lock(&ppeers_lock); 181 q = p->p_peers; 182 while (q != NULL) { 183 PROC_LOCK(q); 184 psignal(q, SIGKILL); 185 PROC_UNLOCK(q); 186 q = q->p_peers; 187 } 188 while (p->p_peers != NULL) 189 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 190 mtx_unlock(&ppeers_lock); 191 } 192 193 PROC_LOCK(p); 194 _STOPEVENT(p, S_EXIT, rv); 195 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ 196 PROC_UNLOCK(p); 197 198 /* 199 * Check if any loadable modules need anything done at process exit. 200 * E.g. SYSV IPC stuff 201 * XXX what if one of these generates an error? 202 */ 203 EVENTHANDLER_INVOKE(process_exit, p); 204 205 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 206 M_ZOMBIE, M_WAITOK); 207 /* 208 * If parent is waiting for us to exit or exec, 209 * P_PPWAIT is set; we will wakeup the parent below. 210 */ 211 PROC_LOCK(p); 212 stopprofclock(p); 213 p->p_flag &= ~(P_TRACED | P_PPWAIT); 214 215 /* 216 * Stop the real interval timer. If the handler is currently 217 * executing, prevent it from rearming itself and let it finish. 218 */ 219 if (timevalisset(&p->p_realtimer.it_value) && 220 callout_stop(&p->p_itcallout) == 0) { 221 timevalclear(&p->p_realtimer.it_interval); 222 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 223 KASSERT(!timevalisset(&p->p_realtimer.it_value), 224 ("realtime timer is still armed")); 225 } 226 sigqueue_flush(&p->p_sigqueue); 227 sigqueue_flush(&td->td_sigqueue); 228 PROC_UNLOCK(p); 229 230 itimers_event_hook(p, ITIMER_EV_EXIT); 231 232 /* 233 * Reset any sigio structures pointing to us as a result of 234 * F_SETOWN with our pid. 235 */ 236 mtx_lock(&Giant); /* XXX: not sure if needed */ 237 funsetownlst(&p->p_sigiolst); 238 239 /* 240 * If this process has an nlminfo data area (for lockd), release it 241 */ 242 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 243 (*nlminfo_release_p)(p); 244 245 /* 246 * Close open files and release open-file table. 247 * This may block! 248 */ 249 fdfree(td); 250 mtx_unlock(&Giant); 251 252 /* 253 * If this thread tickled GEOM, we need to wait for the giggling to 254 * stop before we return to userland 255 */ 256 if (td->td_pflags & TDP_GEOM) 257 g_waitidle(); 258 259 /* 260 * Remove ourself from our leader's peer list and wake our leader. 261 */ 262 mtx_lock(&ppeers_lock); 263 if (p->p_leader->p_peers) { 264 q = p->p_leader; 265 while (q->p_peers != p) 266 q = q->p_peers; 267 q->p_peers = p->p_peers; 268 wakeup(p->p_leader); 269 } 270 mtx_unlock(&ppeers_lock); 271 272 /* The next two chunks should probably be moved to vmspace_exit. */ 273 vm = p->p_vmspace; 274 /* 275 * Release user portion of address space. 276 * This releases references to vnodes, 277 * which could cause I/O if the file has been unlinked. 278 * Need to do this early enough that we can still sleep. 279 * Can't free the entire vmspace as the kernel stack 280 * may be mapped within that space also. 281 * 282 * Processes sharing the same vmspace may exit in one order, and 283 * get cleaned up by vmspace_exit() in a different order. The 284 * last exiting process to reach this point releases as much of 285 * the environment as it can, and the last process cleaned up 286 * by vmspace_exit() (which decrements exitingcnt) cleans up the 287 * remainder. 288 */ 289 atomic_add_int(&vm->vm_exitingcnt, 1); 290 do 291 refcnt = vm->vm_refcnt; 292 while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); 293 if (refcnt == 1) { 294 shmexit(vm); 295 pmap_remove_pages(vmspace_pmap(vm), vm_map_min(&vm->vm_map), 296 vm_map_max(&vm->vm_map)); 297 (void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map), 298 vm_map_max(&vm->vm_map)); 299 } 300 301 mtx_lock(&Giant); 302 sx_xlock(&proctree_lock); 303 if (SESS_LEADER(p)) { 304 struct session *sp; 305 306 sp = p->p_session; 307 if (sp->s_ttyvp) { 308 /* 309 * Controlling process. 310 * Signal foreground pgrp, 311 * drain controlling terminal 312 * and revoke access to controlling terminal. 313 */ 314 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 315 tp = sp->s_ttyp; 316 if (sp->s_ttyp->t_pgrp) { 317 PGRP_LOCK(sp->s_ttyp->t_pgrp); 318 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 319 PGRP_UNLOCK(sp->s_ttyp->t_pgrp); 320 } 321 /* XXX tp should be locked. */ 322 sx_xunlock(&proctree_lock); 323 (void) ttywait(tp); 324 sx_xlock(&proctree_lock); 325 /* 326 * The tty could have been revoked 327 * if we blocked. 328 */ 329 if (sp->s_ttyvp) { 330 ttyvp = sp->s_ttyvp; 331 SESS_LOCK(p->p_session); 332 sp->s_ttyvp = NULL; 333 SESS_UNLOCK(p->p_session); 334 sx_xunlock(&proctree_lock); 335 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td); 336 VOP_REVOKE(ttyvp, REVOKEALL); 337 vput(ttyvp); 338 sx_xlock(&proctree_lock); 339 } 340 } 341 if (sp->s_ttyvp) { 342 ttyvp = sp->s_ttyvp; 343 SESS_LOCK(p->p_session); 344 sp->s_ttyvp = NULL; 345 SESS_UNLOCK(p->p_session); 346 vrele(ttyvp); 347 } 348 /* 349 * s_ttyp is not zero'd; we use this to indicate 350 * that the session once had a controlling terminal. 351 * (for logging and informational purposes) 352 */ 353 } 354 SESS_LOCK(p->p_session); 355 sp->s_leader = NULL; 356 SESS_UNLOCK(p->p_session); 357 } 358 fixjobc(p, p->p_pgrp, 0); 359 sx_xunlock(&proctree_lock); 360 (void)acct_process(td); 361 mtx_unlock(&Giant); 362#ifdef KTRACE 363 /* 364 * release trace file 365 */ 366 PROC_LOCK(p); 367 mtx_lock(&ktrace_mtx); 368 p->p_traceflag = 0; /* don't trace the vrele() */ 369 tracevp = p->p_tracevp; 370 p->p_tracevp = NULL; 371 tracecred = p->p_tracecred; 372 p->p_tracecred = NULL; 373 mtx_unlock(&ktrace_mtx); 374 PROC_UNLOCK(p); 375 if (tracevp != NULL) { 376 mtx_lock(&Giant); 377 vrele(tracevp); 378 mtx_unlock(&Giant); 379 } 380 if (tracecred != NULL) 381 crfree(tracecred); 382#endif 383 /* 384 * Release reference to text vnode 385 */ 386 if ((vtmp = p->p_textvp) != NULL) { 387 p->p_textvp = NULL; 388 mtx_lock(&Giant); 389 vrele(vtmp); 390 mtx_unlock(&Giant); 391 } 392 393 /* 394 * Release our limits structure. 395 */ 396 PROC_LOCK(p); 397 plim = p->p_limit; 398 p->p_limit = NULL; 399 PROC_UNLOCK(p); 400 lim_free(plim); 401 402 /* 403 * Remove proc from allproc queue and pidhash chain. 404 * Place onto zombproc. Unlink from parent's child list. 405 */ 406 sx_xlock(&allproc_lock); 407 LIST_REMOVE(p, p_list); 408 LIST_INSERT_HEAD(&zombproc, p, p_list); 409 LIST_REMOVE(p, p_hash); 410 sx_xunlock(&allproc_lock); 411 412 sx_xlock(&proctree_lock); 413 q = LIST_FIRST(&p->p_children); 414 if (q != NULL) /* only need this if any child is S_ZOMB */ 415 wakeup(initproc); 416 for (; q != NULL; q = nq) { 417 nq = LIST_NEXT(q, p_sibling); 418 PROC_LOCK(q); 419 proc_reparent(q, initproc); 420 q->p_sigparent = SIGCHLD; 421 /* 422 * Traced processes are killed 423 * since their existence means someone is screwing up. 424 */ 425 if (q->p_flag & P_TRACED) { 426 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 427 psignal(q, SIGKILL); 428 } 429 PROC_UNLOCK(q); 430 } 431 432 /* 433 * Save exit status and finalize rusage info except for times, 434 * adding in child rusage info. 435 */ 436 PROC_LOCK(p); 437 p->p_xstat = rv; 438 p->p_xthread = td; 439 p->p_stats->p_ru.ru_nvcsw++; 440 *p->p_ru = p->p_stats->p_ru; 441 ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 442 443 /* 444 * Notify interested parties of our demise. 445 */ 446 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 447 448 /* 449 * Just delete all entries in the p_klist. At this point we won't 450 * report any more events, and there are nasty race conditions that 451 * can beat us if we don't. 452 */ 453 knlist_clear(&p->p_klist, 1); 454 455 /* 456 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 457 * flag set, or if the handler is set to SIG_IGN, notify process 458 * 1 instead (and hope it will handle this situation). 459 */ 460 PROC_LOCK(p->p_pptr); 461 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 462 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 463 struct proc *pp; 464 465 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 466 pp = p->p_pptr; 467 PROC_UNLOCK(pp); 468 proc_reparent(p, initproc); 469 p->p_sigparent = SIGCHLD; 470 PROC_LOCK(p->p_pptr); 471 /* 472 * If this was the last child of our parent, notify 473 * parent, so in case he was wait(2)ing, he will 474 * continue. 475 */ 476 if (LIST_EMPTY(&pp->p_children)) 477 wakeup(pp); 478 } else 479 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 480 481 if (p->p_pptr == initproc) 482 psignal(p->p_pptr, SIGCHLD); 483 else if (p->p_sigparent != 0) 484 psignal(p->p_pptr, p->p_sigparent); 485 PROC_UNLOCK(p->p_pptr); 486 487 /* 488 * If this is a kthread, then wakeup anyone waiting for it to exit. 489 */ 490 if (p->p_flag & P_KTHREAD) 491 wakeup(p); 492 PROC_UNLOCK(p); 493 494 /* 495 * Finally, call machine-dependent code to release the remaining 496 * resources including address space. 497 * The address space is released by "vmspace_exitfree(p)" in 498 * vm_waitproc(). 499 */ 500 cpu_exit(td); 501 502 WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object, 503 "process (pid %d) exiting", p->p_pid); 504 505 PROC_LOCK(p); 506 PROC_LOCK(p->p_pptr); 507 sx_xunlock(&proctree_lock); 508 509 /* 510 * We have to wait until after acquiring all locks before 511 * changing p_state. We need to avoid all possible context 512 * switches (including ones from blocking on a mutex) while 513 * marked as a zombie. We also have to set the zombie state 514 * before we release the parent process' proc lock to avoid 515 * a lost wakeup. So, we first call wakeup, then we grab the 516 * sched lock, update the state, and release the parent process' 517 * proc lock. 518 */ 519 wakeup(p->p_pptr); 520 mtx_lock_spin(&sched_lock); 521 p->p_state = PRS_ZOMBIE; 522 PROC_UNLOCK(p->p_pptr); 523 524 /* Do the same timestamp bookkeeping that mi_switch() would do. */ 525 binuptime(&new_switchtime); 526 bintime_add(&p->p_rux.rux_runtime, &new_switchtime); 527 bintime_sub(&p->p_rux.rux_runtime, PCPU_PTR(switchtime)); 528 PCPU_SET(switchtime, new_switchtime); 529 PCPU_SET(switchticks, ticks); 530 cnt.v_swtch++; 531 532 sched_exit(p->p_pptr, td); 533 534 /* 535 * Hopefully no one will try to deliver a signal to the process this 536 * late in the game. 537 */ 538 knlist_destroy(&p->p_klist); 539 540 /* 541 * Make sure the scheduler takes this thread out of its tables etc. 542 * This will also release this thread's reference to the ucred. 543 * Other thread parts to release include pcb bits and such. 544 */ 545 thread_exit(); 546} 547 548#ifdef COMPAT_43 549/* 550 * The dirty work is handled by kern_wait(). 551 * 552 * MPSAFE. 553 */ 554int 555owait(struct thread *td, struct owait_args *uap __unused) 556{ 557 int error, status; 558 559 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 560 if (error == 0) 561 td->td_retval[1] = status; 562 return (error); 563} 564#endif /* COMPAT_43 */ 565 566/* 567 * The dirty work is handled by kern_wait(). 568 * 569 * MPSAFE. 570 */ 571int 572wait4(struct thread *td, struct wait_args *uap) 573{ 574 struct rusage ru, *rup; 575 int error, status; 576 577 if (uap->rusage != NULL) 578 rup = &ru; 579 else 580 rup = NULL; 581 error = kern_wait(td, uap->pid, &status, uap->options, rup); 582 if (uap->status != NULL && error == 0) 583 error = copyout(&status, uap->status, sizeof(status)); 584 if (uap->rusage != NULL && error == 0) 585 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 586 return (error); 587} 588 589int 590kern_wait(struct thread *td, pid_t pid, int *status, int options, 591 struct rusage *rusage) 592{ 593 struct proc *p, *q, *t; 594 int error, nfound; 595 596 q = td->td_proc; 597 if (pid == 0) { 598 PROC_LOCK(q); 599 pid = -q->p_pgid; 600 PROC_UNLOCK(q); 601 } 602 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 603 return (EINVAL); 604loop: 605 if (q->p_flag & P_STATCHILD) { 606 PROC_LOCK(q); 607 q->p_flag &= ~P_STATCHILD; 608 PROC_UNLOCK(q); 609 } 610 nfound = 0; 611 sx_xlock(&proctree_lock); 612 LIST_FOREACH(p, &q->p_children, p_sibling) { 613 PROC_LOCK(p); 614 if (pid != WAIT_ANY && 615 p->p_pid != pid && p->p_pgid != -pid) { 616 PROC_UNLOCK(p); 617 continue; 618 } 619 if (p_canwait(td, p)) { 620 PROC_UNLOCK(p); 621 continue; 622 } 623 624 /* 625 * This special case handles a kthread spawned by linux_clone 626 * (see linux_misc.c). The linux_wait4 and linux_waitpid 627 * functions need to be able to distinguish between waiting 628 * on a process and waiting on a thread. It is a thread if 629 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 630 * signifies we want to wait for threads and not processes. 631 */ 632 if ((p->p_sigparent != SIGCHLD) ^ 633 ((options & WLINUXCLONE) != 0)) { 634 PROC_UNLOCK(p); 635 continue; 636 } 637 638 nfound++; 639 if (p->p_state == PRS_ZOMBIE) { 640 641 /* 642 * It is possible that the last thread of this 643 * process is still running on another CPU 644 * in thread_exit() after having dropped the process 645 * lock via PROC_UNLOCK() but before it has completed 646 * cpu_throw(). In that case, the other thread must 647 * still hold sched_lock, so simply by acquiring 648 * sched_lock once we will wait long enough for the 649 * thread to exit in that case. 650 */ 651 mtx_lock_spin(&sched_lock); 652 mtx_unlock_spin(&sched_lock); 653 654 td->td_retval[0] = p->p_pid; 655 if (status) 656 *status = p->p_xstat; /* convert to int */ 657 if (rusage) { 658 *rusage = *p->p_ru; 659 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 660 } 661 662 /* 663 * If we got the child via a ptrace 'attach', 664 * we need to give it back to the old parent. 665 */ 666 PROC_UNLOCK(p); 667 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 668 PROC_LOCK(p); 669 p->p_oppid = 0; 670 proc_reparent(p, t); 671 PROC_UNLOCK(p); 672 psignal(t, SIGCHLD); 673 wakeup(t); 674 PROC_UNLOCK(t); 675 sx_xunlock(&proctree_lock); 676 return (0); 677 } 678 679 /* 680 * Remove other references to this process to ensure 681 * we have an exclusive reference. 682 */ 683 sx_xlock(&allproc_lock); 684 LIST_REMOVE(p, p_list); /* off zombproc */ 685 sx_xunlock(&allproc_lock); 686 LIST_REMOVE(p, p_sibling); 687 leavepgrp(p); 688 sx_xunlock(&proctree_lock); 689 690 /* 691 * As a side effect of this lock, we know that 692 * all other writes to this proc are visible now, so 693 * no more locking is needed for p. 694 */ 695 PROC_LOCK(p); 696 p->p_xstat = 0; /* XXX: why? */ 697 PROC_UNLOCK(p); 698 PROC_LOCK(q); 699 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru, 700 &p->p_rux); 701 PROC_UNLOCK(q); 702 FREE(p->p_ru, M_ZOMBIE); 703 p->p_ru = NULL; 704 705 /* 706 * Decrement the count of procs running with this uid. 707 */ 708 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 709 710 /* 711 * Free credentials, arguments, and sigacts. 712 */ 713 crfree(p->p_ucred); 714 p->p_ucred = NULL; 715 pargs_drop(p->p_args); 716 p->p_args = NULL; 717 sigacts_free(p->p_sigacts); 718 p->p_sigacts = NULL; 719 720 /* 721 * Do any thread-system specific cleanups. 722 */ 723 thread_wait(p); 724 725 /* 726 * Give vm and machine-dependent layer a chance 727 * to free anything that cpu_exit couldn't 728 * release while still running in process context. 729 */ 730 vm_waitproc(p); 731#ifdef MAC 732 mac_destroy_proc(p); 733#endif 734 KASSERT(FIRST_THREAD_IN_PROC(p), 735 ("kern_wait: no residual thread!")); 736 uma_zfree(proc_zone, p); 737 sx_xlock(&allproc_lock); 738 nprocs--; 739 sx_xunlock(&allproc_lock); 740 return (0); 741 } 742 mtx_lock_spin(&sched_lock); 743 if ((p->p_flag & P_STOPPED_SIG) && 744 (p->p_suspcount == p->p_numthreads) && 745 (p->p_flag & P_WAITED) == 0 && 746 (p->p_flag & P_TRACED || options & WUNTRACED)) { 747 mtx_unlock_spin(&sched_lock); 748 p->p_flag |= P_WAITED; 749 sx_xunlock(&proctree_lock); 750 td->td_retval[0] = p->p_pid; 751 if (status) 752 *status = W_STOPCODE(p->p_xstat); 753 PROC_UNLOCK(p); 754 return (0); 755 } 756 mtx_unlock_spin(&sched_lock); 757 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 758 sx_xunlock(&proctree_lock); 759 td->td_retval[0] = p->p_pid; 760 p->p_flag &= ~P_CONTINUED; 761 PROC_UNLOCK(p); 762 763 if (status) 764 *status = SIGCONT; 765 return (0); 766 } 767 PROC_UNLOCK(p); 768 } 769 if (nfound == 0) { 770 sx_xunlock(&proctree_lock); 771 return (ECHILD); 772 } 773 if (options & WNOHANG) { 774 sx_xunlock(&proctree_lock); 775 td->td_retval[0] = 0; 776 return (0); 777 } 778 PROC_LOCK(q); 779 sx_xunlock(&proctree_lock); 780 if (q->p_flag & P_STATCHILD) { 781 q->p_flag &= ~P_STATCHILD; 782 error = 0; 783 } else 784 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 785 PROC_UNLOCK(q); 786 if (error) 787 return (error); 788 goto loop; 789} 790 791/* 792 * Make process 'parent' the new parent of process 'child'. 793 * Must be called with an exclusive hold of proctree lock. 794 */ 795void 796proc_reparent(struct proc *child, struct proc *parent) 797{ 798 799 sx_assert(&proctree_lock, SX_XLOCKED); 800 PROC_LOCK_ASSERT(child, MA_OWNED); 801 if (child->p_pptr == parent) 802 return; 803 804 LIST_REMOVE(child, p_sibling); 805 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 806 child->p_pptr = parent; 807} 808