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("$FreeBSD$"); 39 40 #include "opt_compat.h" 41 #include "opt_ktrace.h" 42 #include "opt_mac.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/sysproto.h> 47 #include <sys/eventhandler.h> 48 #include <sys/kernel.h> 49 #include <sys/malloc.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/proc.h> 53 #include <sys/pioctl.h> 54 #include <sys/tty.h> 55 #include <sys/wait.h> 56 #include <sys/vmmeter.h> 57 #include <sys/vnode.h> 58 #include <sys/resourcevar.h> 59 #include <sys/sbuf.h> 60 #include <sys/signalvar.h> 61 #include <sys/sched.h> 62 #include <sys/sx.h> 63 #include <sys/syscallsubr.h> 64 #include <sys/syslog.h> 65 #include <sys/ptrace.h> 66 #include <sys/acct.h> /* for acct_process() function prototype */ 67 #include <sys/filedesc.h> 68 #include <sys/shm.h> 69 #include <sys/sem.h> 70 #ifdef KTRACE 71 #include <sys/ktrace.h> 72 #endif 73 74 #include <security/audit/audit.h> 75 #include <security/mac/mac_framework.h> 76 77 #include <vm/vm.h> 78 #include <vm/vm_extern.h> 79 #include <vm/vm_param.h> 80 #include <vm/pmap.h> 81 #include <vm/vm_map.h> 82 #include <vm/vm_page.h> 83 #include <vm/uma.h> 84 85 /* Required to be non-static for SysVR4 emulator */ 86 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 87 88 /* Hook for NFS teardown procedure. */ 89 void (*nlminfo_release_p)(struct proc *p); 90 91 /* 92 * exit -- death of process. 93 */ 94 void 95 sys_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 to 104 * zombie, and unlink proc from allproc and parent's lists. Save exit status 105 * and rusage for wait(). Check for child processes and orphan them. 106 */ 107 void 108 exit1(struct thread *td, int rv) 109 { 110 struct proc *p, *nq, *q; 111 struct tty *tp; 112 struct vnode *ttyvp; 113 struct vnode *vtmp; 114 #ifdef KTRACE 115 struct vnode *tracevp; 116 struct ucred *tracecred; 117 #endif 118 struct plimit *plim; 119 int locked; 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 KASSERT(p->p_numthreads == 1, 173 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 174 /* 175 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 176 * on our vmspace, so we should block below until they have 177 * released their reference to us. Note that if they have 178 * requested S_EXIT stops we will block here until they ack 179 * via PIOCCONT. 180 */ 181 _STOPEVENT(p, S_EXIT, rv); 182 183 /* 184 * Note that we are exiting and do another wakeup of anyone in 185 * PIOCWAIT in case they aren't listening for S_EXIT stops or 186 * decided to wait again after we told them we are exiting. 187 */ 188 p->p_flag |= P_WEXIT; 189 wakeup(&p->p_stype); 190 191 /* 192 * Wait for any processes that have a hold on our vmspace to 193 * release their reference. 194 */ 195 while (p->p_lock > 0) 196 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 197 198 PROC_UNLOCK(p); 199 /* Drain the limit callout while we don't have the proc locked */ 200 callout_drain(&p->p_limco); 201 202 #ifdef AUDIT 203 /* 204 * The Sun BSM exit token contains two components: an exit status as 205 * passed to exit(), and a return value to indicate what sort of exit 206 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 207 * what the return value is. 208 */ 209 AUDIT_ARG(exit, WEXITSTATUS(rv), 0); 210 AUDIT_SYSCALL_EXIT(0, td); 211 #endif 212 213 /* Are we a task leader? */ 214 if (p == p->p_leader) { 215 mtx_lock(&ppeers_lock); 216 q = p->p_peers; 217 while (q != NULL) { 218 PROC_LOCK(q); 219 psignal(q, SIGKILL); 220 PROC_UNLOCK(q); 221 q = q->p_peers; 222 } 223 while (p->p_peers != NULL) 224 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 225 mtx_unlock(&ppeers_lock); 226 } 227 228 /* 229 * Check if any loadable modules need anything done at process exit. 230 * E.g. SYSV IPC stuff 231 * XXX what if one of these generates an error? 232 */ 233 EVENTHANDLER_INVOKE(process_exit, p); 234 235 /* 236 * If parent is waiting for us to exit or exec, 237 * P_PPWAIT is set; we will wakeup the parent below. 238 */ 239 PROC_LOCK(p); 240 stopprofclock(p); 241 p->p_flag &= ~(P_TRACED | P_PPWAIT); 242 243 /* 244 * Stop the real interval timer. If the handler is currently 245 * executing, prevent it from rearming itself and let it finish. 246 */ 247 if (timevalisset(&p->p_realtimer.it_value) && 248 callout_stop(&p->p_itcallout) == 0) { 249 timevalclear(&p->p_realtimer.it_interval); 250 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 251 KASSERT(!timevalisset(&p->p_realtimer.it_value), 252 ("realtime timer is still armed")); 253 } 254 PROC_UNLOCK(p); 255 256 /* 257 * Reset any sigio structures pointing to us as a result of 258 * F_SETOWN with our pid. 259 */ 260 funsetownlst(&p->p_sigiolst); 261 262 /* 263 * If this process has an nlminfo data area (for lockd), release it 264 */ 265 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 266 (*nlminfo_release_p)(p); 267 268 /* 269 * Close open files and release open-file table. 270 * This may block! 271 */ 272 fdfree(td); 273 274 /* 275 * If this thread tickled GEOM, we need to wait for the giggling to 276 * stop before we return to userland 277 */ 278 if (td->td_pflags & TDP_GEOM) 279 g_waitidle(); 280 281 /* 282 * Remove ourself from our leader's peer list and wake our leader. 283 */ 284 mtx_lock(&ppeers_lock); 285 if (p->p_leader->p_peers) { 286 q = p->p_leader; 287 while (q->p_peers != p) 288 q = q->p_peers; 289 q->p_peers = p->p_peers; 290 wakeup(p->p_leader); 291 } 292 mtx_unlock(&ppeers_lock); 293 294 vmspace_exit(td); 295 296 mtx_lock(&Giant); /* XXX TTY */ 297 sx_xlock(&proctree_lock); 298 if (SESS_LEADER(p)) { 299 struct session *sp; 300 301 sp = p->p_session; 302 if (sp->s_ttyvp) { 303 /* 304 * Controlling process. 305 * Signal foreground pgrp, 306 * drain controlling terminal 307 * and revoke access to controlling terminal. 308 */ 309 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 310 tp = sp->s_ttyp; 311 if (sp->s_ttyp->t_pgrp) { 312 PGRP_LOCK(sp->s_ttyp->t_pgrp); 313 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 314 PGRP_UNLOCK(sp->s_ttyp->t_pgrp); 315 } 316 /* XXX tp should be locked. */ 317 sx_xunlock(&proctree_lock); 318 (void) ttywait(tp); 319 sx_xlock(&proctree_lock); 320 /* 321 * The tty could have been revoked 322 * if we blocked. 323 */ 324 if (sp->s_ttyvp) { 325 ttyvp = sp->s_ttyvp; 326 SESS_LOCK(p->p_session); 327 sp->s_ttyvp = NULL; 328 SESS_UNLOCK(p->p_session); 329 sx_xunlock(&proctree_lock); 330 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td); 331 VOP_REVOKE(ttyvp, REVOKEALL); 332 vput(ttyvp); 333 sx_xlock(&proctree_lock); 334 } 335 } 336 if (sp->s_ttyvp) { 337 ttyvp = sp->s_ttyvp; 338 SESS_LOCK(p->p_session); 339 sp->s_ttyvp = NULL; 340 SESS_UNLOCK(p->p_session); 341 vrele(ttyvp); 342 } 343 /* 344 * s_ttyp is not zero'd; we use this to indicate 345 * that the session once had a controlling terminal. 346 * (for logging and informational purposes) 347 */ 348 } 349 SESS_LOCK(p->p_session); 350 sp->s_leader = NULL; 351 SESS_UNLOCK(p->p_session); 352 } 353 fixjobc(p, p->p_pgrp, 0); 354 sx_xunlock(&proctree_lock); 355 (void)acct_process(td); 356 mtx_unlock(&Giant); 357 #ifdef KTRACE 358 /* 359 * Disable tracing, then drain any pending records and release 360 * the trace file. 361 */ 362 if (p->p_traceflag != 0) { 363 PROC_LOCK(p); 364 mtx_lock(&ktrace_mtx); 365 p->p_traceflag = 0; 366 mtx_unlock(&ktrace_mtx); 367 PROC_UNLOCK(p); 368 ktrprocexit(td); 369 PROC_LOCK(p); 370 mtx_lock(&ktrace_mtx); 371 tracevp = p->p_tracevp; 372 p->p_tracevp = NULL; 373 tracecred = p->p_tracecred; 374 p->p_tracecred = NULL; 375 mtx_unlock(&ktrace_mtx); 376 PROC_UNLOCK(p); 377 if (tracevp != NULL) { 378 locked = VFS_LOCK_GIANT(tracevp->v_mount); 379 vrele(tracevp); 380 VFS_UNLOCK_GIANT(locked); 381 } 382 if (tracecred != NULL) 383 crfree(tracecred); 384 } 385 #endif 386 /* 387 * Release reference to text vnode 388 */ 389 if ((vtmp = p->p_textvp) != NULL) { 390 p->p_textvp = NULL; 391 locked = VFS_LOCK_GIANT(vtmp->v_mount); 392 vrele(vtmp); 393 VFS_UNLOCK_GIANT(locked); 394 } 395 396 /* 397 * Release our limits structure. 398 */ 399 PROC_LOCK(p); 400 plim = p->p_limit; 401 p->p_limit = NULL; 402 PROC_UNLOCK(p); 403 lim_free(plim); 404 405 /* 406 * Remove proc from allproc queue and pidhash chain. 407 * Place onto zombproc. Unlink from parent's child list. 408 */ 409 sx_xlock(&allproc_lock); 410 LIST_REMOVE(p, p_list); 411 LIST_INSERT_HEAD(&zombproc, p, p_list); 412 LIST_REMOVE(p, p_hash); 413 sx_xunlock(&allproc_lock); 414 415 /* 416 * Call machine-dependent code to release any 417 * machine-dependent resources other than the address space. 418 * The address space is released by "vmspace_exitfree(p)" in 419 * vm_waitproc(). 420 */ 421 cpu_exit(td); 422 423 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 424 425 /* 426 * Reparent all of our children to init. 427 */ 428 sx_xlock(&proctree_lock); 429 q = LIST_FIRST(&p->p_children); 430 if (q != NULL) /* only need this if any child is S_ZOMB */ 431 wakeup(initproc); 432 for (; q != NULL; q = nq) { 433 nq = LIST_NEXT(q, p_sibling); 434 PROC_LOCK(q); 435 proc_reparent(q, initproc); 436 q->p_sigparent = SIGCHLD; 437 /* 438 * Traced processes are killed 439 * since their existence means someone is screwing up. 440 */ 441 if (q->p_flag & P_TRACED) { 442 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 443 psignal(q, SIGKILL); 444 } 445 PROC_UNLOCK(q); 446 } 447 448 /* Save exit status. */ 449 PROC_LOCK(p); 450 p->p_xstat = rv; 451 p->p_xthread = td; 452 /* 453 * Notify interested parties of our demise. 454 */ 455 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 456 457 /* 458 * Just delete all entries in the p_klist. At this point we won't 459 * report any more events, and there are nasty race conditions that 460 * can beat us if we don't. 461 */ 462 knlist_clear(&p->p_klist, 1); 463 464 /* 465 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 466 * flag set, or if the handler is set to SIG_IGN, notify process 467 * 1 instead (and hope it will handle this situation). 468 */ 469 PROC_LOCK(p->p_pptr); 470 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 471 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 472 struct proc *pp; 473 474 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 475 pp = p->p_pptr; 476 PROC_UNLOCK(pp); 477 proc_reparent(p, initproc); 478 p->p_sigparent = SIGCHLD; 479 PROC_LOCK(p->p_pptr); 480 /* 481 * If this was the last child of our parent, notify 482 * parent, so in case he was wait(2)ing, he will 483 * continue. 484 */ 485 if (LIST_EMPTY(&pp->p_children)) 486 wakeup(pp); 487 } else 488 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 489 490 if (p->p_pptr == initproc) 491 psignal(p->p_pptr, SIGCHLD); 492 else if (p->p_sigparent != 0) { 493 if (p->p_sigparent == SIGCHLD) 494 childproc_exited(p); 495 else /* LINUX thread */ 496 psignal(p->p_pptr, p->p_sigparent); 497 } 498 sx_xunlock(&proctree_lock); 499 500 /* 501 * The state PRS_ZOMBIE prevents other proesses from sending 502 * signal to the process, to avoid memory leak, we free memory 503 * for signal queue at the time when the state is set. 504 */ 505 sigqueue_flush(&p->p_sigqueue); 506 sigqueue_flush(&td->td_sigqueue); 507 508 /* 509 * We have to wait until after acquiring all locks before 510 * changing p_state. We need to avoid all possible context 511 * switches (including ones from blocking on a mutex) while 512 * marked as a zombie. We also have to set the zombie state 513 * before we release the parent process' proc lock to avoid 514 * a lost wakeup. So, we first call wakeup, then we grab the 515 * sched lock, update the state, and release the parent process' 516 * proc lock. 517 */ 518 wakeup(p->p_pptr); 519 PROC_SLOCK(p->p_pptr); 520 sched_exit(p->p_pptr, td); 521 PROC_SUNLOCK(p->p_pptr); 522 PROC_SLOCK(p); 523 p->p_state = PRS_ZOMBIE; 524 PROC_UNLOCK(p->p_pptr); 525 526 /* 527 * Hopefully no one will try to deliver a signal to the process this 528 * late in the game. 529 */ 530 knlist_destroy(&p->p_klist); 531 532 /* 533 * Save our children's rusage information in our exit rusage. 534 */ 535 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 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 } 544 545 546 #ifndef _SYS_SYSPROTO_H_ 547 struct abort2_args { 548 char *why; 549 int nargs; 550 void **args; 551 }; 552 #endif 553 554 int 555 abort2(struct thread *td, struct abort2_args *uap) 556 { 557 struct proc *p = td->td_proc; 558 struct sbuf *sb; 559 void *uargs[16]; 560 int error, i, sig; 561 562 error = 0; /* satisfy compiler */ 563 564 /* 565 * Do it right now so we can log either proper call of abort2(), or 566 * note, that invalid argument was passed. 512 is big enough to 567 * handle 16 arguments' descriptions with additional comments. 568 */ 569 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 570 sbuf_clear(sb); 571 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 572 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 573 /* 574 * Since we can't return from abort2(), send SIGKILL in cases, where 575 * abort2() was called improperly 576 */ 577 sig = SIGKILL; 578 /* Prevent from DoSes from user-space. */ 579 if (uap->nargs < 0 || uap->nargs > 16) 580 goto out; 581 if (uap->args == NULL) 582 goto out; 583 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 584 if (error != 0) 585 goto out; 586 /* 587 * Limit size of 'reason' string to 128. Will fit even when 588 * maximal number of arguments was chosen to be logged. 589 */ 590 if (uap->why != NULL) { 591 error = sbuf_copyin(sb, uap->why, 128); 592 if (error < 0) 593 goto out; 594 } else { 595 sbuf_printf(sb, "(null)"); 596 } 597 if (uap->nargs) { 598 sbuf_printf(sb, "("); 599 for (i = 0;i < uap->nargs; i++) 600 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 601 sbuf_printf(sb, ")"); 602 } 603 /* 604 * Final stage: arguments were proper, string has been 605 * successfully copied from userspace, and copying pointers 606 * from user-space succeed. 607 */ 608 sig = SIGABRT; 609 out: 610 if (sig == SIGKILL) { 611 sbuf_trim(sb); 612 sbuf_printf(sb, " (Reason text inaccessible)"); 613 } 614 sbuf_cat(sb, "\n"); 615 sbuf_finish(sb); 616 log(LOG_INFO, "%s", sbuf_data(sb)); 617 sbuf_delete(sb); 618 exit1(td, W_EXITCODE(0, sig)); 619 return (0); 620 } 621 622 623 #ifdef COMPAT_43 624 /* 625 * The dirty work is handled by kern_wait(). 626 */ 627 int 628 owait(struct thread *td, struct owait_args *uap __unused) 629 { 630 int error, status; 631 632 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 633 if (error == 0) 634 td->td_retval[1] = status; 635 return (error); 636 } 637 #endif /* COMPAT_43 */ 638 639 /* 640 * The dirty work is handled by kern_wait(). 641 */ 642 int 643 wait4(struct thread *td, struct wait_args *uap) 644 { 645 struct rusage ru, *rup; 646 int error, status; 647 648 if (uap->rusage != NULL) 649 rup = &ru; 650 else 651 rup = NULL; 652 error = kern_wait(td, uap->pid, &status, uap->options, rup); 653 if (uap->status != NULL && error == 0) 654 error = copyout(&status, uap->status, sizeof(status)); 655 if (uap->rusage != NULL && error == 0) 656 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 657 return (error); 658 } 659 660 int 661 kern_wait(struct thread *td, pid_t pid, int *status, int options, 662 struct rusage *rusage) 663 { 664 struct proc *p, *q, *t; 665 int error, nfound; 666 667 AUDIT_ARG(pid, pid); 668 669 q = td->td_proc; 670 if (pid == 0) { 671 PROC_LOCK(q); 672 pid = -q->p_pgid; 673 PROC_UNLOCK(q); 674 } 675 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 676 return (EINVAL); 677 loop: 678 if (q->p_flag & P_STATCHILD) { 679 PROC_LOCK(q); 680 q->p_flag &= ~P_STATCHILD; 681 PROC_UNLOCK(q); 682 } 683 nfound = 0; 684 sx_xlock(&proctree_lock); 685 LIST_FOREACH(p, &q->p_children, p_sibling) { 686 PROC_LOCK(p); 687 if (pid != WAIT_ANY && 688 p->p_pid != pid && p->p_pgid != -pid) { 689 PROC_UNLOCK(p); 690 continue; 691 } 692 if (p_canwait(td, p)) { 693 PROC_UNLOCK(p); 694 continue; 695 } 696 697 /* 698 * This special case handles a kthread spawned by linux_clone 699 * (see linux_misc.c). The linux_wait4 and linux_waitpid 700 * functions need to be able to distinguish between waiting 701 * on a process and waiting on a thread. It is a thread if 702 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 703 * signifies we want to wait for threads and not processes. 704 */ 705 if ((p->p_sigparent != SIGCHLD) ^ 706 ((options & WLINUXCLONE) != 0)) { 707 PROC_UNLOCK(p); 708 continue; 709 } 710 711 nfound++; 712 PROC_SLOCK(p); 713 if (p->p_state == PRS_ZOMBIE) { 714 if (rusage) { 715 *rusage = p->p_ru; 716 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 717 } 718 PROC_SUNLOCK(p); 719 td->td_retval[0] = p->p_pid; 720 if (status) 721 *status = p->p_xstat; /* convert to int */ 722 PROC_LOCK(q); 723 sigqueue_take(p->p_ksi); 724 PROC_UNLOCK(q); 725 726 /* 727 * If we got the child via a ptrace 'attach', 728 * we need to give it back to the old parent. 729 */ 730 PROC_UNLOCK(p); 731 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 732 PROC_LOCK(p); 733 p->p_oppid = 0; 734 proc_reparent(p, t); 735 PROC_UNLOCK(p); 736 tdsignal(t, NULL, SIGCHLD, p->p_ksi); 737 wakeup(t); 738 PROC_UNLOCK(t); 739 sx_xunlock(&proctree_lock); 740 return (0); 741 } 742 743 /* 744 * Remove other references to this process to ensure 745 * we have an exclusive reference. 746 */ 747 sx_xlock(&allproc_lock); 748 LIST_REMOVE(p, p_list); /* off zombproc */ 749 sx_xunlock(&allproc_lock); 750 LIST_REMOVE(p, p_sibling); 751 leavepgrp(p); 752 sx_xunlock(&proctree_lock); 753 754 /* 755 * As a side effect of this lock, we know that 756 * all other writes to this proc are visible now, so 757 * no more locking is needed for p. 758 */ 759 PROC_LOCK(p); 760 p->p_xstat = 0; /* XXX: why? */ 761 PROC_UNLOCK(p); 762 PROC_LOCK(q); 763 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, 764 &p->p_rux); 765 PROC_UNLOCK(q); 766 767 /* 768 * Decrement the count of procs running with this uid. 769 */ 770 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 771 772 /* 773 * Free credentials, arguments, and sigacts. 774 */ 775 crfree(p->p_ucred); 776 p->p_ucred = NULL; 777 pargs_drop(p->p_args); 778 p->p_args = NULL; 779 sigacts_free(p->p_sigacts); 780 p->p_sigacts = NULL; 781 782 /* 783 * Do any thread-system specific cleanups. 784 */ 785 thread_wait(p); 786 787 /* 788 * Give vm and machine-dependent layer a chance 789 * to free anything that cpu_exit couldn't 790 * release while still running in process context. 791 */ 792 vm_waitproc(p); 793 #ifdef MAC 794 mac_destroy_proc(p); 795 #endif 796 KASSERT(FIRST_THREAD_IN_PROC(p), 797 ("kern_wait: no residual thread!")); 798 uma_zfree(proc_zone, p); 799 sx_xlock(&allproc_lock); 800 nprocs--; 801 sx_xunlock(&allproc_lock); 802 return (0); 803 } 804 if ((p->p_flag & P_STOPPED_SIG) && 805 (p->p_suspcount == p->p_numthreads) && 806 (p->p_flag & P_WAITED) == 0 && 807 (p->p_flag & P_TRACED || options & WUNTRACED)) { 808 PROC_SUNLOCK(p); 809 p->p_flag |= P_WAITED; 810 sx_xunlock(&proctree_lock); 811 td->td_retval[0] = p->p_pid; 812 if (status) 813 *status = W_STOPCODE(p->p_xstat); 814 815 PROC_LOCK(q); 816 sigqueue_take(p->p_ksi); 817 PROC_UNLOCK(q); 818 PROC_UNLOCK(p); 819 820 return (0); 821 } 822 PROC_SUNLOCK(p); 823 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 824 sx_xunlock(&proctree_lock); 825 td->td_retval[0] = p->p_pid; 826 p->p_flag &= ~P_CONTINUED; 827 828 PROC_LOCK(q); 829 sigqueue_take(p->p_ksi); 830 PROC_UNLOCK(q); 831 PROC_UNLOCK(p); 832 833 if (status) 834 *status = SIGCONT; 835 return (0); 836 } 837 PROC_UNLOCK(p); 838 } 839 if (nfound == 0) { 840 sx_xunlock(&proctree_lock); 841 return (ECHILD); 842 } 843 if (options & WNOHANG) { 844 sx_xunlock(&proctree_lock); 845 td->td_retval[0] = 0; 846 return (0); 847 } 848 PROC_LOCK(q); 849 sx_xunlock(&proctree_lock); 850 if (q->p_flag & P_STATCHILD) { 851 q->p_flag &= ~P_STATCHILD; 852 error = 0; 853 } else 854 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 855 PROC_UNLOCK(q); 856 if (error) 857 return (error); 858 goto loop; 859 } 860 861 /* 862 * Make process 'parent' the new parent of process 'child'. 863 * Must be called with an exclusive hold of proctree lock. 864 */ 865 void 866 proc_reparent(struct proc *child, struct proc *parent) 867 { 868 869 sx_assert(&proctree_lock, SX_XLOCKED); 870 PROC_LOCK_ASSERT(child, MA_OWNED); 871 if (child->p_pptr == parent) 872 return; 873 874 PROC_LOCK(child->p_pptr); 875 sigqueue_take(child->p_ksi); 876 PROC_UNLOCK(child->p_pptr); 877 LIST_REMOVE(child, p_sibling); 878 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 879 child->p_pptr = parent; 880 }
Cache object: cc295fb2214317f853de1834abcc9a77
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