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/6.0/sys/kern/kern_exit.c 151755 2005-10-27 18:35:19Z 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 #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 bintime new_switchtime; 110 struct proc *p, *nq, *q; 111 struct tty *tp; 112 struct vnode *ttyvp; 113 struct vmspace *vm; 114 struct vnode *vtmp; 115 #ifdef KTRACE 116 struct vnode *tracevp; 117 struct ucred *tracecred; 118 #endif 119 struct plimit *plim; 120 int refcnt; 121 122 /* 123 * Drop Giant if caller has it. Eventually we should warn about 124 * being called with Giant held. 125 */ 126 while (mtx_owned(&Giant)) 127 mtx_unlock(&Giant); 128 129 p = td->td_proc; 130 if (p == initproc) { 131 printf("init died (signal %d, exit %d)\n", 132 WTERMSIG(rv), WEXITSTATUS(rv)); 133 panic("Going nowhere without my init!"); 134 } 135 136 /* 137 * MUST abort all other threads before proceeding past here. 138 */ 139 PROC_LOCK(p); 140 if (p->p_flag & P_HADTHREADS) { 141 retry: 142 /* 143 * First check if some other thread got here before us.. 144 * if so, act apropriatly, (exit or suspend); 145 */ 146 thread_suspend_check(0); 147 148 /* 149 * Kill off the other threads. This requires 150 * some co-operation from other parts of the kernel 151 * so it may not be instantaneous. With this state set 152 * any thread entering the kernel from userspace will 153 * thread_exit() in trap(). Any thread attempting to 154 * sleep will return immediately with EINTR or EWOULDBLOCK 155 * which will hopefully force them to back out to userland 156 * freeing resources as they go. Any thread attempting 157 * to return to userland will thread_exit() from userret(). 158 * thread_exit() will unsuspend us when the last of the 159 * other threads exits. 160 * If there is already a thread singler after resumption, 161 * calling thread_single will fail; in that case, we just 162 * re-check all suspension request, the thread should 163 * either be suspended there or exit. 164 */ 165 if (thread_single(SINGLE_EXIT)) 166 goto retry; 167 168 /* 169 * All other activity in this process is now stopped. 170 * Threading support has been turned off. 171 */ 172 } 173 174 p->p_flag |= P_WEXIT; 175 PROC_UNLOCK(p); 176 177 /* Are we a task leader? */ 178 if (p == p->p_leader) { 179 mtx_lock(&ppeers_lock); 180 q = p->p_peers; 181 while (q != NULL) { 182 PROC_LOCK(q); 183 psignal(q, SIGKILL); 184 PROC_UNLOCK(q); 185 q = q->p_peers; 186 } 187 while (p->p_peers != NULL) 188 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 189 mtx_unlock(&ppeers_lock); 190 } 191 192 PROC_LOCK(p); 193 _STOPEVENT(p, S_EXIT, rv); 194 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ 195 PROC_UNLOCK(p); 196 197 /* 198 * Check if any loadable modules need anything done at process exit. 199 * E.g. SYSV IPC stuff 200 * XXX what if one of these generates an error? 201 */ 202 EVENTHANDLER_INVOKE(process_exit, p); 203 204 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 205 M_ZOMBIE, M_WAITOK); 206 /* 207 * If parent is waiting for us to exit or exec, 208 * P_PPWAIT is set; we will wakeup the parent below. 209 */ 210 PROC_LOCK(p); 211 stopprofclock(p); 212 p->p_flag &= ~(P_TRACED | P_PPWAIT); 213 SIGEMPTYSET(p->p_siglist); 214 SIGEMPTYSET(td->td_siglist); 215 216 /* 217 * Stop the real interval timer. If the handler is currently 218 * executing, prevent it from rearming itself and let it finish. 219 */ 220 if (timevalisset(&p->p_realtimer.it_value) && 221 callout_stop(&p->p_itcallout) == 0) { 222 timevalclear(&p->p_realtimer.it_interval); 223 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 224 KASSERT(!timevalisset(&p->p_realtimer.it_value), 225 ("realtime timer is still armed")); 226 } 227 PROC_UNLOCK(p); 228 229 /* 230 * Reset any sigio structures pointing to us as a result of 231 * F_SETOWN with our pid. 232 */ 233 mtx_lock(&Giant); /* XXX: not sure if needed */ 234 funsetownlst(&p->p_sigiolst); 235 236 /* 237 * If this process has an nlminfo data area (for lockd), release it 238 */ 239 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 240 (*nlminfo_release_p)(p); 241 242 /* 243 * Close open files and release open-file table. 244 * This may block! 245 */ 246 fdfree(td); 247 mtx_unlock(&Giant); 248 249 /* 250 * If this thread tickled GEOM, we need to wait for the giggling to 251 * stop before we return to userland 252 */ 253 if (td->td_pflags & TDP_GEOM) 254 g_waitidle(); 255 256 /* 257 * Remove ourself from our leader's peer list and wake our leader. 258 */ 259 mtx_lock(&ppeers_lock); 260 if (p->p_leader->p_peers) { 261 q = p->p_leader; 262 while (q->p_peers != p) 263 q = q->p_peers; 264 q->p_peers = p->p_peers; 265 wakeup(p->p_leader); 266 } 267 mtx_unlock(&ppeers_lock); 268 269 /* The next two chunks should probably be moved to vmspace_exit. */ 270 vm = p->p_vmspace; 271 /* 272 * Release user portion of address space. 273 * This releases references to vnodes, 274 * which could cause I/O if the file has been unlinked. 275 * Need to do this early enough that we can still sleep. 276 * Can't free the entire vmspace as the kernel stack 277 * may be mapped within that space also. 278 * 279 * Processes sharing the same vmspace may exit in one order, and 280 * get cleaned up by vmspace_exit() in a different order. The 281 * last exiting process to reach this point releases as much of 282 * the environment as it can, and the last process cleaned up 283 * by vmspace_exit() (which decrements exitingcnt) cleans up the 284 * remainder. 285 */ 286 atomic_add_int(&vm->vm_exitingcnt, 1); 287 do 288 refcnt = vm->vm_refcnt; 289 while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); 290 if (refcnt == 1) { 291 shmexit(vm); 292 pmap_remove_pages(vmspace_pmap(vm), vm_map_min(&vm->vm_map), 293 vm_map_max(&vm->vm_map)); 294 (void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map), 295 vm_map_max(&vm->vm_map)); 296 } 297 298 mtx_lock(&Giant); 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 * release trace file 362 */ 363 PROC_LOCK(p); 364 mtx_lock(&ktrace_mtx); 365 p->p_traceflag = 0; /* don't trace the vrele() */ 366 tracevp = p->p_tracevp; 367 p->p_tracevp = NULL; 368 tracecred = p->p_tracecred; 369 p->p_tracecred = NULL; 370 mtx_unlock(&ktrace_mtx); 371 PROC_UNLOCK(p); 372 if (tracevp != NULL) { 373 mtx_lock(&Giant); 374 vrele(tracevp); 375 mtx_unlock(&Giant); 376 } 377 if (tracecred != NULL) 378 crfree(tracecred); 379 #endif 380 /* 381 * Release reference to text vnode 382 */ 383 if ((vtmp = p->p_textvp) != NULL) { 384 p->p_textvp = NULL; 385 mtx_lock(&Giant); 386 vrele(vtmp); 387 mtx_unlock(&Giant); 388 } 389 390 /* 391 * Release our limits structure. 392 */ 393 PROC_LOCK(p); 394 plim = p->p_limit; 395 p->p_limit = NULL; 396 PROC_UNLOCK(p); 397 lim_free(plim); 398 399 /* 400 * Remove proc from allproc queue and pidhash chain. 401 * Place onto zombproc. Unlink from parent's child list. 402 */ 403 sx_xlock(&allproc_lock); 404 LIST_REMOVE(p, p_list); 405 LIST_INSERT_HEAD(&zombproc, p, p_list); 406 LIST_REMOVE(p, p_hash); 407 sx_xunlock(&allproc_lock); 408 409 sx_xlock(&proctree_lock); 410 q = LIST_FIRST(&p->p_children); 411 if (q != NULL) /* only need this if any child is S_ZOMB */ 412 wakeup(initproc); 413 for (; q != NULL; q = nq) { 414 nq = LIST_NEXT(q, p_sibling); 415 PROC_LOCK(q); 416 proc_reparent(q, initproc); 417 q->p_sigparent = SIGCHLD; 418 /* 419 * Traced processes are killed 420 * since their existence means someone is screwing up. 421 */ 422 if (q->p_flag & P_TRACED) { 423 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 424 psignal(q, SIGKILL); 425 } 426 PROC_UNLOCK(q); 427 } 428 429 /* 430 * Save exit status and finalize rusage info except for times, 431 * adding in child rusage info. 432 */ 433 PROC_LOCK(p); 434 p->p_xstat = rv; 435 p->p_xthread = td; 436 p->p_stats->p_ru.ru_nvcsw++; 437 *p->p_ru = p->p_stats->p_ru; 438 ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 439 440 /* 441 * Notify interested parties of our demise. 442 */ 443 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 444 445 /* 446 * Just delete all entries in the p_klist. At this point we won't 447 * report any more events, and there are nasty race conditions that 448 * can beat us if we don't. 449 */ 450 knlist_clear(&p->p_klist, 1); 451 452 /* 453 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 454 * flag set, or if the handler is set to SIG_IGN, notify process 455 * 1 instead (and hope it will handle this situation). 456 */ 457 PROC_LOCK(p->p_pptr); 458 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 459 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 460 struct proc *pp; 461 462 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 463 pp = p->p_pptr; 464 PROC_UNLOCK(pp); 465 proc_reparent(p, initproc); 466 p->p_sigparent = SIGCHLD; 467 PROC_LOCK(p->p_pptr); 468 /* 469 * If this was the last child of our parent, notify 470 * parent, so in case he was wait(2)ing, he will 471 * continue. 472 */ 473 if (LIST_EMPTY(&pp->p_children)) 474 wakeup(pp); 475 } else 476 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 477 478 if (p->p_pptr == initproc) 479 psignal(p->p_pptr, SIGCHLD); 480 else if (p->p_sigparent != 0) 481 psignal(p->p_pptr, p->p_sigparent); 482 PROC_UNLOCK(p->p_pptr); 483 484 /* 485 * If this is a kthread, then wakeup anyone waiting for it to exit. 486 */ 487 if (p->p_flag & P_KTHREAD) 488 wakeup(p); 489 PROC_UNLOCK(p); 490 491 /* 492 * Finally, call machine-dependent code to release the remaining 493 * resources including address space. 494 * The address space is released by "vmspace_exitfree(p)" in 495 * vm_waitproc(). 496 */ 497 cpu_exit(td); 498 499 WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object, 500 "process (pid %d) exiting", p->p_pid); 501 502 PROC_LOCK(p); 503 PROC_LOCK(p->p_pptr); 504 sx_xunlock(&proctree_lock); 505 506 /* 507 * We have to wait until after acquiring all locks before 508 * changing p_state. We need to avoid all possible context 509 * switches (including ones from blocking on a mutex) while 510 * marked as a zombie. We also have to set the zombie state 511 * before we release the parent process' proc lock to avoid 512 * a lost wakeup. So, we first call wakeup, then we grab the 513 * sched lock, update the state, and release the parent process' 514 * proc lock. 515 */ 516 wakeup(p->p_pptr); 517 mtx_lock_spin(&sched_lock); 518 p->p_state = PRS_ZOMBIE; 519 PROC_UNLOCK(p->p_pptr); 520 521 /* Do the same timestamp bookkeeping that mi_switch() would do. */ 522 binuptime(&new_switchtime); 523 bintime_add(&p->p_rux.rux_runtime, &new_switchtime); 524 bintime_sub(&p->p_rux.rux_runtime, PCPU_PTR(switchtime)); 525 PCPU_SET(switchtime, new_switchtime); 526 PCPU_SET(switchticks, ticks); 527 cnt.v_swtch++; 528 529 sched_exit(p->p_pptr, td); 530 531 /* 532 * Hopefully no one will try to deliver a signal to the process this 533 * late in the game. 534 */ 535 knlist_destroy(&p->p_klist); 536 537 /* 538 * Make sure the scheduler takes this thread out of its tables etc. 539 * This will also release this thread's reference to the ucred. 540 * Other thread parts to release include pcb bits and such. 541 */ 542 thread_exit(); 543 } 544 545 #ifdef COMPAT_43 546 /* 547 * The dirty work is handled by kern_wait(). 548 * 549 * MPSAFE. 550 */ 551 int 552 owait(struct thread *td, struct owait_args *uap __unused) 553 { 554 int error, status; 555 556 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 557 if (error == 0) 558 td->td_retval[1] = status; 559 return (error); 560 } 561 #endif /* COMPAT_43 */ 562 563 /* 564 * The dirty work is handled by kern_wait(). 565 * 566 * MPSAFE. 567 */ 568 int 569 wait4(struct thread *td, struct wait_args *uap) 570 { 571 struct rusage ru, *rup; 572 int error, status; 573 574 if (uap->rusage != NULL) 575 rup = &ru; 576 else 577 rup = NULL; 578 error = kern_wait(td, uap->pid, &status, uap->options, rup); 579 if (uap->status != NULL && error == 0) 580 error = copyout(&status, uap->status, sizeof(status)); 581 if (uap->rusage != NULL && error == 0) 582 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 583 return (error); 584 } 585 586 int 587 kern_wait(struct thread *td, pid_t pid, int *status, int options, 588 struct rusage *rusage) 589 { 590 struct proc *p, *q, *t; 591 int error, nfound; 592 593 q = td->td_proc; 594 if (pid == 0) { 595 PROC_LOCK(q); 596 pid = -q->p_pgid; 597 PROC_UNLOCK(q); 598 } 599 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 600 return (EINVAL); 601 loop: 602 if (q->p_flag & P_STATCHILD) { 603 PROC_LOCK(q); 604 q->p_flag &= ~P_STATCHILD; 605 PROC_UNLOCK(q); 606 } 607 nfound = 0; 608 sx_xlock(&proctree_lock); 609 LIST_FOREACH(p, &q->p_children, p_sibling) { 610 PROC_LOCK(p); 611 if (pid != WAIT_ANY && 612 p->p_pid != pid && p->p_pgid != -pid) { 613 PROC_UNLOCK(p); 614 continue; 615 } 616 if (p_canwait(td, p)) { 617 PROC_UNLOCK(p); 618 continue; 619 } 620 621 /* 622 * This special case handles a kthread spawned by linux_clone 623 * (see linux_misc.c). The linux_wait4 and linux_waitpid 624 * functions need to be able to distinguish between waiting 625 * on a process and waiting on a thread. It is a thread if 626 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 627 * signifies we want to wait for threads and not processes. 628 */ 629 if ((p->p_sigparent != SIGCHLD) ^ 630 ((options & WLINUXCLONE) != 0)) { 631 PROC_UNLOCK(p); 632 continue; 633 } 634 635 nfound++; 636 if (p->p_state == PRS_ZOMBIE) { 637 638 /* 639 * It is possible that the last thread of this 640 * process is still running on another CPU 641 * in thread_exit() after having dropped the process 642 * lock via PROC_UNLOCK() but before it has completed 643 * cpu_throw(). In that case, the other thread must 644 * still hold sched_lock, so simply by acquiring 645 * sched_lock once we will wait long enough for the 646 * thread to exit in that case. 647 */ 648 mtx_lock_spin(&sched_lock); 649 mtx_unlock_spin(&sched_lock); 650 651 td->td_retval[0] = p->p_pid; 652 if (status) 653 *status = p->p_xstat; /* convert to int */ 654 if (rusage) { 655 *rusage = *p->p_ru; 656 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 657 } 658 659 /* 660 * If we got the child via a ptrace 'attach', 661 * we need to give it back to the old parent. 662 */ 663 PROC_UNLOCK(p); 664 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 665 PROC_LOCK(p); 666 p->p_oppid = 0; 667 proc_reparent(p, t); 668 PROC_UNLOCK(p); 669 psignal(t, SIGCHLD); 670 wakeup(t); 671 PROC_UNLOCK(t); 672 sx_xunlock(&proctree_lock); 673 return (0); 674 } 675 676 /* 677 * Remove other references to this process to ensure 678 * we have an exclusive reference. 679 */ 680 sx_xlock(&allproc_lock); 681 LIST_REMOVE(p, p_list); /* off zombproc */ 682 sx_xunlock(&allproc_lock); 683 LIST_REMOVE(p, p_sibling); 684 leavepgrp(p); 685 sx_xunlock(&proctree_lock); 686 687 /* 688 * As a side effect of this lock, we know that 689 * all other writes to this proc are visible now, so 690 * no more locking is needed for p. 691 */ 692 PROC_LOCK(p); 693 p->p_xstat = 0; /* XXX: why? */ 694 PROC_UNLOCK(p); 695 PROC_LOCK(q); 696 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru, 697 &p->p_rux); 698 PROC_UNLOCK(q); 699 FREE(p->p_ru, M_ZOMBIE); 700 p->p_ru = NULL; 701 702 /* 703 * Decrement the count of procs running with this uid. 704 */ 705 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 706 707 /* 708 * Free credentials, arguments, and sigacts. 709 */ 710 crfree(p->p_ucred); 711 p->p_ucred = NULL; 712 pargs_drop(p->p_args); 713 p->p_args = NULL; 714 sigacts_free(p->p_sigacts); 715 p->p_sigacts = NULL; 716 717 /* 718 * Do any thread-system specific cleanups. 719 */ 720 thread_wait(p); 721 722 /* 723 * Give vm and machine-dependent layer a chance 724 * to free anything that cpu_exit couldn't 725 * release while still running in process context. 726 */ 727 vm_waitproc(p); 728 #ifdef MAC 729 mac_destroy_proc(p); 730 #endif 731 KASSERT(FIRST_THREAD_IN_PROC(p), 732 ("kern_wait: no residual thread!")); 733 uma_zfree(proc_zone, p); 734 sx_xlock(&allproc_lock); 735 nprocs--; 736 sx_xunlock(&allproc_lock); 737 return (0); 738 } 739 mtx_lock_spin(&sched_lock); 740 if ((p->p_flag & P_STOPPED_SIG) && 741 (p->p_suspcount == p->p_numthreads) && 742 (p->p_flag & P_WAITED) == 0 && 743 (p->p_flag & P_TRACED || options & WUNTRACED)) { 744 mtx_unlock_spin(&sched_lock); 745 p->p_flag |= P_WAITED; 746 sx_xunlock(&proctree_lock); 747 td->td_retval[0] = p->p_pid; 748 if (status) 749 *status = W_STOPCODE(p->p_xstat); 750 PROC_UNLOCK(p); 751 return (0); 752 } 753 mtx_unlock_spin(&sched_lock); 754 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 755 sx_xunlock(&proctree_lock); 756 td->td_retval[0] = p->p_pid; 757 p->p_flag &= ~P_CONTINUED; 758 PROC_UNLOCK(p); 759 760 if (status) 761 *status = SIGCONT; 762 return (0); 763 } 764 PROC_UNLOCK(p); 765 } 766 if (nfound == 0) { 767 sx_xunlock(&proctree_lock); 768 return (ECHILD); 769 } 770 if (options & WNOHANG) { 771 sx_xunlock(&proctree_lock); 772 td->td_retval[0] = 0; 773 return (0); 774 } 775 PROC_LOCK(q); 776 sx_xunlock(&proctree_lock); 777 if (q->p_flag & P_STATCHILD) { 778 q->p_flag &= ~P_STATCHILD; 779 error = 0; 780 } else 781 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 782 PROC_UNLOCK(q); 783 if (error) 784 return (error); 785 goto loop; 786 } 787 788 /* 789 * Make process 'parent' the new parent of process 'child'. 790 * Must be called with an exclusive hold of proctree lock. 791 */ 792 void 793 proc_reparent(struct proc *child, struct proc *parent) 794 { 795 796 sx_assert(&proctree_lock, SX_XLOCKED); 797 PROC_LOCK_ASSERT(child, MA_OWNED); 798 if (child->p_pptr == parent) 799 return; 800 801 LIST_REMOVE(child, p_sibling); 802 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 803 child->p_pptr = parent; 804 }
Cache object: d79be30ad98d622ff23752f65fb346fa
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