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