Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c
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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: releng/6.1/sys/kern/kern_exit.c 158179 2006-04-30 16:44:43Z cvs2svn $"); 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 #ifdef KTRACE 70 #include <sys/ktrace.h> 71 #endif 72 73 #include <vm/vm.h> 74 #include <vm/vm_extern.h> 75 #include <vm/vm_param.h> 76 #include <vm/pmap.h> 77 #include <vm/vm_map.h> 78 #include <vm/vm_page.h> 79 #include <vm/uma.h> 80 81 /* Required to be non-static for SysVR4 emulator */ 82 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 83 84 /* Hook for NFS teardown procedure. */ 85 void (*nlminfo_release_p)(struct proc *p); 86 87 /* 88 * exit -- 89 * Death of process. 90 * 91 * MPSAFE 92 */ 93 void 94 sys_exit(struct thread *td, struct sys_exit_args *uap) 95 { 96 97 exit1(td, W_EXITCODE(uap->rval, 0)); 98 /* NOTREACHED */ 99 } 100 101 /* 102 * Exit: deallocate address space and other resources, change proc state 103 * to zombie, and unlink proc from allproc and parent's lists. Save exit 104 * status and rusage for wait(). Check for child processes and orphan them. 105 */ 106 void 107 exit1(struct thread *td, int rv) 108 { 109 struct proc *p, *nq, *q; 110 struct tty *tp; 111 struct vnode *ttyvp; 112 struct vmspace *vm; 113 struct vnode *vtmp; 114 #ifdef KTRACE 115 struct vnode *tracevp; 116 struct ucred *tracecred; 117 #endif 118 struct plimit *plim; 119 int locked, refcnt; 120 121 /* 122 * Drop Giant if caller has it. Eventually we should warn about 123 * being called with Giant held. 124 */ 125 while (mtx_owned(&Giant)) 126 mtx_unlock(&Giant); 127 128 p = td->td_proc; 129 if (p == initproc) { 130 printf("init died (signal %d, exit %d)\n", 131 WTERMSIG(rv), WEXITSTATUS(rv)); 132 panic("Going nowhere without my init!"); 133 } 134 135 /* 136 * MUST abort all other threads before proceeding past here. 137 */ 138 PROC_LOCK(p); 139 if (p->p_flag & P_HADTHREADS) { 140 retry: 141 /* 142 * First check if some other thread got here before us.. 143 * if so, act apropriatly, (exit or suspend); 144 */ 145 thread_suspend_check(0); 146 147 /* 148 * Kill off the other threads. This requires 149 * some co-operation from other parts of the kernel 150 * so it may not be instantaneous. With this state set 151 * any thread entering the kernel from userspace will 152 * thread_exit() in trap(). Any thread attempting to 153 * sleep will return immediately with EINTR or EWOULDBLOCK 154 * which will hopefully force them to back out to userland 155 * freeing resources as they go. Any thread attempting 156 * to return to userland will thread_exit() from userret(). 157 * thread_exit() will unsuspend us when the last of the 158 * other threads exits. 159 * If there is already a thread singler after resumption, 160 * calling thread_single will fail; in that case, we just 161 * re-check all suspension request, the thread should 162 * either be suspended there or exit. 163 */ 164 if (thread_single(SINGLE_EXIT)) 165 goto retry; 166 167 /* 168 * All other activity in this process is now stopped. 169 * Threading support has been turned off. 170 */ 171 } 172 173 /* 174 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 175 * on our vmspace, so we should block below until they have 176 * released their reference to us. Note that if they have 177 * requested S_EXIT stops we will block here until they ack 178 * via PIOCCONT. 179 */ 180 _STOPEVENT(p, S_EXIT, rv); 181 182 /* 183 * Note that we are exiting and do another wakeup of anyone in 184 * PIOCWAIT in case they aren't listening for S_EXIT stops or 185 * decided to wait again after we told them we are exiting. 186 */ 187 p->p_flag |= P_WEXIT; 188 wakeup(&p->p_stype); 189 190 /* 191 * Wait for any processes that have a hold on our vmspace to 192 * release their reference. 193 */ 194 while (p->p_lock > 0) 195 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 196 PROC_UNLOCK(p); 197 198 /* Are we a task leader? */ 199 if (p == p->p_leader) { 200 mtx_lock(&ppeers_lock); 201 q = p->p_peers; 202 while (q != NULL) { 203 PROC_LOCK(q); 204 psignal(q, SIGKILL); 205 PROC_UNLOCK(q); 206 q = q->p_peers; 207 } 208 while (p->p_peers != NULL) 209 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 210 mtx_unlock(&ppeers_lock); 211 } 212 213 /* 214 * Check if any loadable modules need anything done at process exit. 215 * E.g. SYSV IPC stuff 216 * XXX what if one of these generates an error? 217 */ 218 EVENTHANDLER_INVOKE(process_exit, p); 219 220 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 221 M_ZOMBIE, M_WAITOK); 222 /* 223 * If parent is waiting for us to exit or exec, 224 * P_PPWAIT is set; we will wakeup the parent below. 225 */ 226 PROC_LOCK(p); 227 stopprofclock(p); 228 p->p_flag &= ~(P_TRACED | P_PPWAIT); 229 SIGEMPTYSET(p->p_siglist); 230 SIGEMPTYSET(td->td_siglist); 231 232 /* 233 * Stop the real interval timer. If the handler is currently 234 * executing, prevent it from rearming itself and let it finish. 235 */ 236 if (timevalisset(&p->p_realtimer.it_value) && 237 callout_stop(&p->p_itcallout) == 0) { 238 timevalclear(&p->p_realtimer.it_interval); 239 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 240 KASSERT(!timevalisset(&p->p_realtimer.it_value), 241 ("realtime timer is still armed")); 242 } 243 PROC_UNLOCK(p); 244 245 /* 246 * Reset any sigio structures pointing to us as a result of 247 * F_SETOWN with our pid. 248 */ 249 mtx_lock(&Giant); /* XXX: not sure if needed */ 250 funsetownlst(&p->p_sigiolst); 251 mtx_unlock(&Giant); 252 253 /* 254 * If this process has an nlminfo data area (for lockd), release it 255 */ 256 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 257 (*nlminfo_release_p)(p); 258 259 /* 260 * Close open files and release open-file table. 261 * This may block! 262 */ 263 fdfree(td); 264 265 /* 266 * If this thread tickled GEOM, we need to wait for the giggling to 267 * stop before we return to userland 268 */ 269 if (td->td_pflags & TDP_GEOM) 270 g_waitidle(); 271 272 /* 273 * Remove ourself from our leader's peer list and wake our leader. 274 */ 275 mtx_lock(&ppeers_lock); 276 if (p->p_leader->p_peers) { 277 q = p->p_leader; 278 while (q->p_peers != p) 279 q = q->p_peers; 280 q->p_peers = p->p_peers; 281 wakeup(p->p_leader); 282 } 283 mtx_unlock(&ppeers_lock); 284 285 /* The next two chunks should probably be moved to vmspace_exit. */ 286 vm = p->p_vmspace; 287 /* 288 * Release user portion of address space. 289 * This releases references to vnodes, 290 * which could cause I/O if the file has been unlinked. 291 * Need to do this early enough that we can still sleep. 292 * Can't free the entire vmspace as the kernel stack 293 * may be mapped within that space also. 294 * 295 * Processes sharing the same vmspace may exit in one order, and 296 * get cleaned up by vmspace_exit() in a different order. The 297 * last exiting process to reach this point releases as much of 298 * the environment as it can, and the last process cleaned up 299 * by vmspace_exit() (which decrements exitingcnt) cleans up the 300 * remainder. 301 */ 302 atomic_add_int(&vm->vm_exitingcnt, 1); 303 do 304 refcnt = vm->vm_refcnt; 305 while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); 306 if (refcnt == 1) { 307 shmexit(vm); 308 pmap_remove_pages(vmspace_pmap(vm), vm_map_min(&vm->vm_map), 309 vm_map_max(&vm->vm_map)); 310 (void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map), 311 vm_map_max(&vm->vm_map)); 312 } 313 314 sx_xlock(&proctree_lock); 315 if (SESS_LEADER(p)) { 316 struct session *sp; 317 318 sp = p->p_session; 319 if (sp->s_ttyvp) { 320 locked = VFS_LOCK_GIANT(sp->s_ttyvp->v_mount); 321 /* 322 * Controlling process. 323 * Signal foreground pgrp, 324 * drain controlling terminal 325 * and revoke access to controlling terminal. 326 */ 327 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 328 tp = sp->s_ttyp; 329 if (sp->s_ttyp->t_pgrp) { 330 PGRP_LOCK(sp->s_ttyp->t_pgrp); 331 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 332 PGRP_UNLOCK(sp->s_ttyp->t_pgrp); 333 } 334 /* XXX tp should be locked. */ 335 sx_xunlock(&proctree_lock); 336 (void) ttywait(tp); 337 sx_xlock(&proctree_lock); 338 /* 339 * The tty could have been revoked 340 * if we blocked. 341 */ 342 if (sp->s_ttyvp) { 343 ttyvp = sp->s_ttyvp; 344 SESS_LOCK(p->p_session); 345 sp->s_ttyvp = NULL; 346 SESS_UNLOCK(p->p_session); 347 sx_xunlock(&proctree_lock); 348 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td); 349 VOP_REVOKE(ttyvp, REVOKEALL); 350 vput(ttyvp); 351 sx_xlock(&proctree_lock); 352 } 353 } 354 if (sp->s_ttyvp) { 355 ttyvp = sp->s_ttyvp; 356 SESS_LOCK(p->p_session); 357 sp->s_ttyvp = NULL; 358 SESS_UNLOCK(p->p_session); 359 vrele(ttyvp); 360 } 361 /* 362 * s_ttyp is not zero'd; we use this to indicate 363 * that the session once had a controlling terminal. 364 * (for logging and informational purposes) 365 */ 366 VFS_UNLOCK_GIANT(locked); 367 } 368 SESS_LOCK(p->p_session); 369 sp->s_leader = NULL; 370 SESS_UNLOCK(p->p_session); 371 } 372 fixjobc(p, p->p_pgrp, 0); 373 sx_xunlock(&proctree_lock); 374 (void)acct_process(td); 375 #ifdef KTRACE 376 /* 377 * release trace file 378 */ 379 PROC_LOCK(p); 380 mtx_lock(&ktrace_mtx); 381 p->p_traceflag = 0; /* don't trace the vrele() */ 382 tracevp = p->p_tracevp; 383 p->p_tracevp = NULL; 384 tracecred = p->p_tracecred; 385 p->p_tracecred = NULL; 386 mtx_unlock(&ktrace_mtx); 387 PROC_UNLOCK(p); 388 if (tracevp != NULL) { 389 locked = VFS_LOCK_GIANT(tracevp->v_mount); 390 vrele(tracevp); 391 VFS_UNLOCK_GIANT(locked); 392 } 393 if (tracecred != NULL) 394 crfree(tracecred); 395 #endif 396 /* 397 * Release reference to text vnode 398 */ 399 if ((vtmp = p->p_textvp) != NULL) { 400 p->p_textvp = NULL; 401 locked = VFS_LOCK_GIANT(vtmp->v_mount); 402 vrele(vtmp); 403 VFS_UNLOCK_GIANT(locked); 404 } 405 406 /* 407 * Release our limits structure. 408 */ 409 PROC_LOCK(p); 410 plim = p->p_limit; 411 p->p_limit = NULL; 412 PROC_UNLOCK(p); 413 lim_free(plim); 414 415 /* 416 * Remove proc from allproc queue and pidhash chain. 417 * Place onto zombproc. Unlink from parent's child list. 418 */ 419 sx_xlock(&allproc_lock); 420 LIST_REMOVE(p, p_list); 421 LIST_INSERT_HEAD(&zombproc, p, p_list); 422 LIST_REMOVE(p, p_hash); 423 sx_xunlock(&allproc_lock); 424 425 sx_xlock(&proctree_lock); 426 q = LIST_FIRST(&p->p_children); 427 if (q != NULL) /* only need this if any child is S_ZOMB */ 428 wakeup(initproc); 429 for (; q != NULL; q = nq) { 430 nq = LIST_NEXT(q, p_sibling); 431 PROC_LOCK(q); 432 proc_reparent(q, initproc); 433 q->p_sigparent = SIGCHLD; 434 /* 435 * Traced processes are killed 436 * since their existence means someone is screwing up. 437 */ 438 if (q->p_flag & P_TRACED) { 439 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 440 psignal(q, SIGKILL); 441 } 442 PROC_UNLOCK(q); 443 } 444 445 /* 446 * Save exit status and finalize rusage info except for times, 447 * adding in child rusage info. 448 */ 449 PROC_LOCK(p); 450 p->p_xstat = rv; 451 p->p_xthread = td; 452 p->p_stats->p_ru.ru_nvcsw++; 453 *p->p_ru = p->p_stats->p_ru; 454 455 /* 456 * Notify interested parties of our demise. 457 */ 458 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 459 460 /* 461 * Just delete all entries in the p_klist. At this point we won't 462 * report any more events, and there are nasty race conditions that 463 * can beat us if we don't. 464 */ 465 knlist_clear(&p->p_klist, 1); 466 467 /* 468 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 469 * flag set, or if the handler is set to SIG_IGN, notify process 470 * 1 instead (and hope it will handle this situation). 471 */ 472 PROC_LOCK(p->p_pptr); 473 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 474 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 475 struct proc *pp; 476 477 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 478 pp = p->p_pptr; 479 PROC_UNLOCK(pp); 480 proc_reparent(p, initproc); 481 p->p_sigparent = SIGCHLD; 482 PROC_LOCK(p->p_pptr); 483 /* 484 * If this was the last child of our parent, notify 485 * parent, so in case he was wait(2)ing, he will 486 * continue. 487 */ 488 if (LIST_EMPTY(&pp->p_children)) 489 wakeup(pp); 490 } else 491 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 492 493 if (p->p_pptr == initproc) 494 psignal(p->p_pptr, SIGCHLD); 495 else if (p->p_sigparent != 0) 496 psignal(p->p_pptr, p->p_sigparent); 497 PROC_UNLOCK(p->p_pptr); 498 499 /* 500 * If this is a kthread, then wakeup anyone waiting for it to exit. 501 */ 502 if (p->p_flag & P_KTHREAD) 503 wakeup(p); 504 PROC_UNLOCK(p); 505 506 /* 507 * Finally, call machine-dependent code to release the remaining 508 * resources including address space. 509 * The address space is released by "vmspace_exitfree(p)" in 510 * vm_waitproc(). 511 */ 512 cpu_exit(td); 513 514 WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object, 515 "process (pid %d) exiting", p->p_pid); 516 517 PROC_LOCK(p); 518 PROC_LOCK(p->p_pptr); 519 sx_xunlock(&proctree_lock); 520 521 /* 522 * We have to wait until after acquiring all locks before 523 * changing p_state. We need to avoid all possible context 524 * switches (including ones from blocking on a mutex) while 525 * marked as a zombie. We also have to set the zombie state 526 * before we release the parent process' proc lock to avoid 527 * a lost wakeup. So, we first call wakeup, then we grab the 528 * sched lock, update the state, and release the parent process' 529 * proc lock. 530 */ 531 wakeup(p->p_pptr); 532 mtx_lock_spin(&sched_lock); 533 p->p_state = PRS_ZOMBIE; 534 PROC_UNLOCK(p->p_pptr); 535 536 sched_exit(p->p_pptr, td); 537 538 /* 539 * Hopefully no one will try to deliver a signal to the process this 540 * late in the game. 541 */ 542 knlist_destroy(&p->p_klist); 543 544 /* 545 * Make sure the scheduler takes this thread out of its tables etc. 546 * This will also release this thread's reference to the ucred. 547 * Other thread parts to release include pcb bits and such. 548 */ 549 thread_exit(); 550 } 551 552 #ifdef COMPAT_43 553 /* 554 * The dirty work is handled by kern_wait(). 555 * 556 * MPSAFE. 557 */ 558 int 559 owait(struct thread *td, struct owait_args *uap __unused) 560 { 561 int error, status; 562 563 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 564 if (error == 0) 565 td->td_retval[1] = status; 566 return (error); 567 } 568 #endif /* COMPAT_43 */ 569 570 /* 571 * The dirty work is handled by kern_wait(). 572 * 573 * MPSAFE. 574 */ 575 int 576 wait4(struct thread *td, struct wait_args *uap) 577 { 578 struct rusage ru, *rup; 579 int error, status; 580 581 if (uap->rusage != NULL) 582 rup = &ru; 583 else 584 rup = NULL; 585 error = kern_wait(td, uap->pid, &status, uap->options, rup); 586 if (uap->status != NULL && error == 0) 587 error = copyout(&status, uap->status, sizeof(status)); 588 if (uap->rusage != NULL && error == 0) 589 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 590 return (error); 591 } 592 593 int 594 kern_wait(struct thread *td, pid_t pid, int *status, int options, 595 struct rusage *rusage) 596 { 597 struct proc *p, *q, *t; 598 int error, nfound; 599 600 q = td->td_proc; 601 if (pid == 0) { 602 PROC_LOCK(q); 603 pid = -q->p_pgid; 604 PROC_UNLOCK(q); 605 } 606 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 607 return (EINVAL); 608 loop: 609 if (q->p_flag & P_STATCHILD) { 610 PROC_LOCK(q); 611 q->p_flag &= ~P_STATCHILD; 612 PROC_UNLOCK(q); 613 } 614 nfound = 0; 615 sx_xlock(&proctree_lock); 616 LIST_FOREACH(p, &q->p_children, p_sibling) { 617 PROC_LOCK(p); 618 if (pid != WAIT_ANY && 619 p->p_pid != pid && p->p_pgid != -pid) { 620 PROC_UNLOCK(p); 621 continue; 622 } 623 if (p_canwait(td, p)) { 624 PROC_UNLOCK(p); 625 continue; 626 } 627 628 /* 629 * This special case handles a kthread spawned by linux_clone 630 * (see linux_misc.c). The linux_wait4 and linux_waitpid 631 * functions need to be able to distinguish between waiting 632 * on a process and waiting on a thread. It is a thread if 633 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 634 * signifies we want to wait for threads and not processes. 635 */ 636 if ((p->p_sigparent != SIGCHLD) ^ 637 ((options & WLINUXCLONE) != 0)) { 638 PROC_UNLOCK(p); 639 continue; 640 } 641 642 nfound++; 643 if (p->p_state == PRS_ZOMBIE) { 644 645 /* 646 * It is possible that the last thread of this 647 * process is still running on another CPU 648 * in thread_exit() after having dropped the process 649 * lock via PROC_UNLOCK() but before it has completed 650 * cpu_throw(). In that case, the other thread must 651 * still hold sched_lock, so simply by acquiring 652 * sched_lock once we will wait long enough for the 653 * thread to exit in that case. 654 */ 655 mtx_lock_spin(&sched_lock); 656 mtx_unlock_spin(&sched_lock); 657 658 td->td_retval[0] = p->p_pid; 659 if (status) 660 *status = p->p_xstat; /* convert to int */ 661 if (rusage) { 662 *rusage = *p->p_ru; 663 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 664 } 665 666 /* 667 * If we got the child via a ptrace 'attach', 668 * we need to give it back to the old parent. 669 */ 670 PROC_UNLOCK(p); 671 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 672 PROC_LOCK(p); 673 p->p_oppid = 0; 674 proc_reparent(p, t); 675 PROC_UNLOCK(p); 676 psignal(t, SIGCHLD); 677 wakeup(t); 678 PROC_UNLOCK(t); 679 sx_xunlock(&proctree_lock); 680 return (0); 681 } 682 683 /* 684 * Remove other references to this process to ensure 685 * we have an exclusive reference. 686 */ 687 sx_xlock(&allproc_lock); 688 LIST_REMOVE(p, p_list); /* off zombproc */ 689 sx_xunlock(&allproc_lock); 690 LIST_REMOVE(p, p_sibling); 691 leavepgrp(p); 692 sx_xunlock(&proctree_lock); 693 694 /* 695 * As a side effect of this lock, we know that 696 * all other writes to this proc are visible now, so 697 * no more locking is needed for p. 698 */ 699 PROC_LOCK(p); 700 p->p_xstat = 0; /* XXX: why? */ 701 PROC_UNLOCK(p); 702 PROC_LOCK(q); 703 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru, 704 &p->p_rux); 705 PROC_UNLOCK(q); 706 FREE(p->p_ru, M_ZOMBIE); 707 p->p_ru = NULL; 708 709 /* 710 * Decrement the count of procs running with this uid. 711 */ 712 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 713 714 /* 715 * Free credentials, arguments, and sigacts. 716 */ 717 crfree(p->p_ucred); 718 p->p_ucred = NULL; 719 pargs_drop(p->p_args); 720 p->p_args = NULL; 721 sigacts_free(p->p_sigacts); 722 p->p_sigacts = NULL; 723 724 /* 725 * Do any thread-system specific cleanups. 726 */ 727 thread_wait(p); 728 729 /* 730 * Give vm and machine-dependent layer a chance 731 * to free anything that cpu_exit couldn't 732 * release while still running in process context. 733 */ 734 vm_waitproc(p); 735 #ifdef MAC 736 mac_destroy_proc(p); 737 #endif 738 KASSERT(FIRST_THREAD_IN_PROC(p), 739 ("kern_wait: no residual thread!")); 740 uma_zfree(proc_zone, p); 741 sx_xlock(&allproc_lock); 742 nprocs--; 743 sx_xunlock(&allproc_lock); 744 return (0); 745 } 746 mtx_lock_spin(&sched_lock); 747 if ((p->p_flag & P_STOPPED_SIG) && 748 (p->p_suspcount == p->p_numthreads) && 749 (p->p_flag & P_WAITED) == 0 && 750 (p->p_flag & P_TRACED || options & WUNTRACED)) { 751 mtx_unlock_spin(&sched_lock); 752 p->p_flag |= P_WAITED; 753 sx_xunlock(&proctree_lock); 754 td->td_retval[0] = p->p_pid; 755 if (status) 756 *status = W_STOPCODE(p->p_xstat); 757 PROC_UNLOCK(p); 758 return (0); 759 } 760 mtx_unlock_spin(&sched_lock); 761 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 762 sx_xunlock(&proctree_lock); 763 td->td_retval[0] = p->p_pid; 764 p->p_flag &= ~P_CONTINUED; 765 PROC_UNLOCK(p); 766 767 if (status) 768 *status = SIGCONT; 769 return (0); 770 } 771 PROC_UNLOCK(p); 772 } 773 if (nfound == 0) { 774 sx_xunlock(&proctree_lock); 775 return (ECHILD); 776 } 777 if (options & WNOHANG) { 778 sx_xunlock(&proctree_lock); 779 td->td_retval[0] = 0; 780 return (0); 781 } 782 PROC_LOCK(q); 783 sx_xunlock(&proctree_lock); 784 if (q->p_flag & P_STATCHILD) { 785 q->p_flag &= ~P_STATCHILD; 786 error = 0; 787 } else 788 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 789 PROC_UNLOCK(q); 790 if (error) 791 return (error); 792 goto loop; 793 } 794 795 /* 796 * Make process 'parent' the new parent of process 'child'. 797 * Must be called with an exclusive hold of proctree lock. 798 */ 799 void 800 proc_reparent(struct proc *child, struct proc *parent) 801 { 802 803 sx_assert(&proctree_lock, SX_XLOCKED); 804 PROC_LOCK_ASSERT(child, MA_OWNED); 805 if (child->p_pptr == parent) 806 return; 807 808 LIST_REMOVE(child, p_sibling); 809 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 810 child->p_pptr = parent; 811 }
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