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_kdtrace.h" 42 #include "opt_ktrace.h" 43 #include "opt_mac.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/sysproto.h> 48 #include <sys/eventhandler.h> 49 #include <sys/kernel.h> 50 #include <sys/malloc.h> 51 #include <sys/lock.h> 52 #include <sys/mutex.h> 53 #include <sys/proc.h> 54 #include <sys/pioctl.h> 55 #include <sys/tty.h> 56 #include <sys/wait.h> 57 #include <sys/vmmeter.h> 58 #include <sys/vnode.h> 59 #include <sys/resourcevar.h> 60 #include <sys/sbuf.h> 61 #include <sys/signalvar.h> 62 #include <sys/sched.h> 63 #include <sys/sx.h> 64 #include <sys/syscallsubr.h> 65 #include <sys/syslog.h> 66 #include <sys/ptrace.h> 67 #include <sys/acct.h> /* for acct_process() function prototype */ 68 #include <sys/filedesc.h> 69 #include <sys/sdt.h> 70 #include <sys/shm.h> 71 #include <sys/sem.h> 72 #ifdef KTRACE 73 #include <sys/ktrace.h> 74 #endif 75 76 #include <security/audit/audit.h> 77 #include <security/mac/mac_framework.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_extern.h> 81 #include <vm/vm_param.h> 82 #include <vm/pmap.h> 83 #include <vm/vm_map.h> 84 #include <vm/vm_page.h> 85 #include <vm/uma.h> 86 87 #ifdef KDTRACE_HOOKS 88 #include <sys/dtrace_bsd.h> 89 dtrace_execexit_func_t dtrace_fasttrap_exit; 90 #endif 91 92 SDT_PROVIDER_DECLARE(proc); 93 SDT_PROBE_DEFINE(proc, kernel, , exit); 94 SDT_PROBE_ARGTYPE(proc, kernel, , exit, 0, "int"); 95 96 /* Required to be non-static for SysVR4 emulator */ 97 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 98 99 /* Hook for NFS teardown procedure. */ 100 void (*nlminfo_release_p)(struct proc *p); 101 102 /* 103 * exit -- death of process. 104 */ 105 void 106 sys_exit(struct thread *td, struct sys_exit_args *uap) 107 { 108 109 exit1(td, W_EXITCODE(uap->rval, 0)); 110 /* NOTREACHED */ 111 } 112 113 /* 114 * Exit: deallocate address space and other resources, change proc state to 115 * zombie, and unlink proc from allproc and parent's lists. Save exit status 116 * and rusage for wait(). Check for child processes and orphan them. 117 */ 118 void 119 exit1(struct thread *td, int rv) 120 { 121 struct proc *p, *nq, *q; 122 struct vnode *vtmp; 123 struct vnode *ttyvp = NULL; 124 #ifdef KTRACE 125 struct vnode *tracevp; 126 struct ucred *tracecred; 127 #endif 128 struct plimit *plim; 129 int locked; 130 131 mtx_assert(&Giant, MA_NOTOWNED); 132 133 p = td->td_proc; 134 if (p == initproc) { 135 printf("init died (signal %d, exit %d)\n", 136 WTERMSIG(rv), WEXITSTATUS(rv)); 137 panic("Going nowhere without my init!"); 138 } 139 140 /* 141 * MUST abort all other threads before proceeding past here. 142 */ 143 PROC_LOCK(p); 144 while (p->p_flag & P_HADTHREADS) { 145 /* 146 * First check if some other thread got here before us.. 147 * if so, act apropriatly, (exit or suspend); 148 */ 149 thread_suspend_check(0); 150 151 /* 152 * Kill off the other threads. This requires 153 * some co-operation from other parts of the kernel 154 * so it may not be instantaneous. With this state set 155 * any thread entering the kernel from userspace will 156 * thread_exit() in trap(). Any thread attempting to 157 * sleep will return immediately with EINTR or EWOULDBLOCK 158 * which will hopefully force them to back out to userland 159 * freeing resources as they go. Any thread attempting 160 * to return to userland will thread_exit() from userret(). 161 * thread_exit() will unsuspend us when the last of the 162 * other threads exits. 163 * If there is already a thread singler after resumption, 164 * calling thread_single will fail; in that case, we just 165 * re-check all suspension request, the thread should 166 * either be suspended there or exit. 167 */ 168 if (! thread_single(SINGLE_EXIT)) 169 break; 170 171 /* 172 * All other activity in this process is now stopped. 173 * Threading support has been turned off. 174 */ 175 } 176 KASSERT(p->p_numthreads == 1, 177 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 178 /* 179 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 180 * on our vmspace, so we should block below until they have 181 * released their reference to us. Note that if they have 182 * requested S_EXIT stops we will block here until they ack 183 * via PIOCCONT. 184 */ 185 _STOPEVENT(p, S_EXIT, rv); 186 187 /* 188 * Note that we are exiting and do another wakeup of anyone in 189 * PIOCWAIT in case they aren't listening for S_EXIT stops or 190 * decided to wait again after we told them we are exiting. 191 */ 192 p->p_flag |= P_WEXIT; 193 wakeup(&p->p_stype); 194 195 /* 196 * Wait for any processes that have a hold on our vmspace to 197 * release their reference. 198 */ 199 while (p->p_lock > 0) 200 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 201 202 PROC_UNLOCK(p); 203 /* Drain the limit callout while we don't have the proc locked */ 204 callout_drain(&p->p_limco); 205 206 #ifdef AUDIT 207 /* 208 * The Sun BSM exit token contains two components: an exit status as 209 * passed to exit(), and a return value to indicate what sort of exit 210 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 211 * what the return value is. 212 */ 213 AUDIT_ARG(exit, WEXITSTATUS(rv), 0); 214 AUDIT_SYSCALL_EXIT(0, td); 215 #endif 216 217 /* Are we a task leader? */ 218 if (p == p->p_leader) { 219 mtx_lock(&ppeers_lock); 220 q = p->p_peers; 221 while (q != NULL) { 222 PROC_LOCK(q); 223 psignal(q, SIGKILL); 224 PROC_UNLOCK(q); 225 q = q->p_peers; 226 } 227 while (p->p_peers != NULL) 228 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 229 mtx_unlock(&ppeers_lock); 230 } 231 232 /* 233 * Check if any loadable modules need anything done at process exit. 234 * E.g. SYSV IPC stuff 235 * XXX what if one of these generates an error? 236 */ 237 EVENTHANDLER_INVOKE(process_exit, p); 238 239 /* 240 * If parent is waiting for us to exit or exec, 241 * P_PPWAIT is set; we will wakeup the parent below. 242 */ 243 PROC_LOCK(p); 244 stopprofclock(p); 245 p->p_flag &= ~(P_TRACED | P_PPWAIT); 246 247 /* 248 * Stop the real interval timer. If the handler is currently 249 * executing, prevent it from rearming itself and let it finish. 250 */ 251 if (timevalisset(&p->p_realtimer.it_value) && 252 callout_stop(&p->p_itcallout) == 0) { 253 timevalclear(&p->p_realtimer.it_interval); 254 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 255 KASSERT(!timevalisset(&p->p_realtimer.it_value), 256 ("realtime timer is still armed")); 257 } 258 PROC_UNLOCK(p); 259 260 /* 261 * Reset any sigio structures pointing to us as a result of 262 * F_SETOWN with our pid. 263 */ 264 funsetownlst(&p->p_sigiolst); 265 266 /* 267 * If this process has an nlminfo data area (for lockd), release it 268 */ 269 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 270 (*nlminfo_release_p)(p); 271 272 /* 273 * Close open files and release open-file table. 274 * This may block! 275 */ 276 fdfree(td); 277 278 /* 279 * If this thread tickled GEOM, we need to wait for the giggling to 280 * stop before we return to userland 281 */ 282 if (td->td_pflags & TDP_GEOM) 283 g_waitidle(); 284 285 /* 286 * Remove ourself from our leader's peer list and wake our leader. 287 */ 288 mtx_lock(&ppeers_lock); 289 if (p->p_leader->p_peers) { 290 q = p->p_leader; 291 while (q->p_peers != p) 292 q = q->p_peers; 293 q->p_peers = p->p_peers; 294 wakeup(p->p_leader); 295 } 296 mtx_unlock(&ppeers_lock); 297 298 vmspace_exit(td); 299 300 sx_xlock(&proctree_lock); 301 if (SESS_LEADER(p)) { 302 struct session *sp; 303 304 sp = p->p_session; 305 306 SESS_LOCK(sp); 307 ttyvp = sp->s_ttyvp; 308 sp->s_ttyvp = NULL; 309 SESS_UNLOCK(sp); 310 311 if (ttyvp != NULL) { 312 /* 313 * Controlling process. 314 * Signal foreground pgrp and revoke access to 315 * controlling terminal. 316 * 317 * There is no need to drain the terminal here, 318 * because this will be done on revocation. 319 */ 320 if (sp->s_ttyp != NULL) { 321 struct tty *tp = sp->s_ttyp; 322 323 tty_lock(tp); 324 tty_signal_pgrp(tp, SIGHUP); 325 tty_unlock(tp); 326 327 /* 328 * The tty could have been revoked 329 * if we blocked. 330 */ 331 if (ttyvp->v_type != VBAD) { 332 sx_xunlock(&proctree_lock); 333 VOP_LOCK(ttyvp, LK_EXCLUSIVE); 334 VOP_REVOKE(ttyvp, REVOKEALL); 335 VOP_UNLOCK(ttyvp, 0); 336 sx_xlock(&proctree_lock); 337 } 338 } 339 /* 340 * s_ttyp is not zero'd; we use this to indicate that 341 * the session once had a controlling terminal. 342 * (for logging and informational purposes) 343 */ 344 } 345 SESS_LOCK(p->p_session); 346 sp->s_leader = NULL; 347 SESS_UNLOCK(p->p_session); 348 } 349 fixjobc(p, p->p_pgrp, 0); 350 sx_xunlock(&proctree_lock); 351 (void)acct_process(td); 352 353 /* Release the TTY now we've unlocked everything. */ 354 if (ttyvp != NULL) 355 vrele(ttyvp); 356 #ifdef KTRACE 357 /* 358 * Disable tracing, then drain any pending records and release 359 * the trace file. 360 */ 361 if (p->p_traceflag != 0) { 362 PROC_LOCK(p); 363 mtx_lock(&ktrace_mtx); 364 p->p_traceflag = 0; 365 mtx_unlock(&ktrace_mtx); 366 PROC_UNLOCK(p); 367 ktrprocexit(td); 368 PROC_LOCK(p); 369 mtx_lock(&ktrace_mtx); 370 tracevp = p->p_tracevp; 371 p->p_tracevp = NULL; 372 tracecred = p->p_tracecred; 373 p->p_tracecred = NULL; 374 mtx_unlock(&ktrace_mtx); 375 PROC_UNLOCK(p); 376 if (tracevp != NULL) { 377 locked = VFS_LOCK_GIANT(tracevp->v_mount); 378 vrele(tracevp); 379 VFS_UNLOCK_GIANT(locked); 380 } 381 if (tracecred != NULL) 382 crfree(tracecred); 383 } 384 #endif 385 /* 386 * Release reference to text vnode 387 */ 388 if ((vtmp = p->p_textvp) != NULL) { 389 p->p_textvp = NULL; 390 locked = VFS_LOCK_GIANT(vtmp->v_mount); 391 vrele(vtmp); 392 VFS_UNLOCK_GIANT(locked); 393 } 394 395 /* 396 * Release our limits structure. 397 */ 398 PROC_LOCK(p); 399 plim = p->p_limit; 400 p->p_limit = NULL; 401 PROC_UNLOCK(p); 402 lim_free(plim); 403 404 /* 405 * Remove proc from allproc queue and pidhash chain. 406 * Place onto zombproc. Unlink from parent's child list. 407 */ 408 sx_xlock(&allproc_lock); 409 LIST_REMOVE(p, p_list); 410 LIST_INSERT_HEAD(&zombproc, p, p_list); 411 LIST_REMOVE(p, p_hash); 412 sx_xunlock(&allproc_lock); 413 414 /* 415 * Call machine-dependent code to release any 416 * machine-dependent resources other than the address space. 417 * The address space is released by "vmspace_exitfree(p)" in 418 * vm_waitproc(). 419 */ 420 cpu_exit(td); 421 422 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 423 424 /* 425 * Reparent all of our children to init. 426 */ 427 sx_xlock(&proctree_lock); 428 q = LIST_FIRST(&p->p_children); 429 if (q != NULL) /* only need this if any child is S_ZOMB */ 430 wakeup(initproc); 431 for (; q != NULL; q = nq) { 432 nq = LIST_NEXT(q, p_sibling); 433 PROC_LOCK(q); 434 proc_reparent(q, initproc); 435 q->p_sigparent = SIGCHLD; 436 /* 437 * Traced processes are killed 438 * since their existence means someone is screwing up. 439 */ 440 if (q->p_flag & P_TRACED) { 441 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 442 psignal(q, SIGKILL); 443 } 444 PROC_UNLOCK(q); 445 } 446 447 /* Save exit status. */ 448 PROC_LOCK(p); 449 p->p_xstat = rv; 450 p->p_xthread = td; 451 452 #ifdef KDTRACE_HOOKS 453 /* 454 * Tell the DTrace fasttrap provider about the exit if it 455 * has declared an interest. 456 */ 457 if (dtrace_fasttrap_exit) 458 dtrace_fasttrap_exit(p); 459 #endif 460 461 /* 462 * Notify interested parties of our demise. 463 */ 464 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 465 466 #ifdef KDTRACE_HOOKS 467 int reason = CLD_EXITED; 468 if (WCOREDUMP(rv)) 469 reason = CLD_DUMPED; 470 else if (WIFSIGNALED(rv)) 471 reason = CLD_KILLED; 472 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 473 #endif 474 475 /* 476 * Just delete all entries in the p_klist. At this point we won't 477 * report any more events, and there are nasty race conditions that 478 * can beat us if we don't. 479 */ 480 knlist_clear(&p->p_klist, 1); 481 482 /* 483 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 484 * flag set, or if the handler is set to SIG_IGN, notify process 485 * 1 instead (and hope it will handle this situation). 486 */ 487 PROC_LOCK(p->p_pptr); 488 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 489 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 490 struct proc *pp; 491 492 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 493 pp = p->p_pptr; 494 PROC_UNLOCK(pp); 495 proc_reparent(p, initproc); 496 p->p_sigparent = SIGCHLD; 497 PROC_LOCK(p->p_pptr); 498 /* 499 * If this was the last child of our parent, notify 500 * parent, so in case he was wait(2)ing, he will 501 * continue. 502 */ 503 if (LIST_EMPTY(&pp->p_children)) 504 wakeup(pp); 505 } else 506 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 507 508 if (p->p_pptr == initproc) 509 psignal(p->p_pptr, SIGCHLD); 510 else if (p->p_sigparent != 0) { 511 if (p->p_sigparent == SIGCHLD) 512 childproc_exited(p); 513 else /* LINUX thread */ 514 psignal(p->p_pptr, p->p_sigparent); 515 } 516 sx_xunlock(&proctree_lock); 517 518 /* 519 * The state PRS_ZOMBIE prevents other proesses from sending 520 * signal to the process, to avoid memory leak, we free memory 521 * for signal queue at the time when the state is set. 522 */ 523 sigqueue_flush(&p->p_sigqueue); 524 sigqueue_flush(&td->td_sigqueue); 525 526 /* 527 * We have to wait until after acquiring all locks before 528 * changing p_state. We need to avoid all possible context 529 * switches (including ones from blocking on a mutex) while 530 * marked as a zombie. We also have to set the zombie state 531 * before we release the parent process' proc lock to avoid 532 * a lost wakeup. So, we first call wakeup, then we grab the 533 * sched lock, update the state, and release the parent process' 534 * proc lock. 535 */ 536 wakeup(p->p_pptr); 537 sched_exit(p->p_pptr, td); 538 PROC_SLOCK(p); 539 p->p_state = PRS_ZOMBIE; 540 PROC_UNLOCK(p->p_pptr); 541 542 /* 543 * Hopefully no one will try to deliver a signal to the process this 544 * late in the game. 545 */ 546 knlist_destroy(&p->p_klist); 547 548 /* 549 * Save our children's rusage information in our exit rusage. 550 */ 551 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 552 553 /* 554 * Make sure the scheduler takes this thread out of its tables etc. 555 * This will also release this thread's reference to the ucred. 556 * Other thread parts to release include pcb bits and such. 557 */ 558 thread_exit(); 559 } 560 561 562 #ifndef _SYS_SYSPROTO_H_ 563 struct abort2_args { 564 char *why; 565 int nargs; 566 void **args; 567 }; 568 #endif 569 570 int 571 abort2(struct thread *td, struct abort2_args *uap) 572 { 573 struct proc *p = td->td_proc; 574 struct sbuf *sb; 575 void *uargs[16]; 576 int error, i, sig; 577 578 error = 0; /* satisfy compiler */ 579 580 /* 581 * Do it right now so we can log either proper call of abort2(), or 582 * note, that invalid argument was passed. 512 is big enough to 583 * handle 16 arguments' descriptions with additional comments. 584 */ 585 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 586 sbuf_clear(sb); 587 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 588 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 589 /* 590 * Since we can't return from abort2(), send SIGKILL in cases, where 591 * abort2() was called improperly 592 */ 593 sig = SIGKILL; 594 /* Prevent from DoSes from user-space. */ 595 if (uap->nargs < 0 || uap->nargs > 16) 596 goto out; 597 if (uap->nargs > 0) { 598 if (uap->args == NULL) 599 goto out; 600 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 601 if (error != 0) 602 goto out; 603 } 604 /* 605 * Limit size of 'reason' string to 128. Will fit even when 606 * maximal number of arguments was chosen to be logged. 607 */ 608 if (uap->why != NULL) { 609 error = sbuf_copyin(sb, uap->why, 128); 610 if (error < 0) 611 goto out; 612 } else { 613 sbuf_printf(sb, "(null)"); 614 } 615 if (uap->nargs > 0) { 616 sbuf_printf(sb, "("); 617 for (i = 0;i < uap->nargs; i++) 618 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 619 sbuf_printf(sb, ")"); 620 } 621 /* 622 * Final stage: arguments were proper, string has been 623 * successfully copied from userspace, and copying pointers 624 * from user-space succeed. 625 */ 626 sig = SIGABRT; 627 out: 628 if (sig == SIGKILL) { 629 sbuf_trim(sb); 630 sbuf_printf(sb, " (Reason text inaccessible)"); 631 } 632 sbuf_cat(sb, "\n"); 633 sbuf_finish(sb); 634 log(LOG_INFO, "%s", sbuf_data(sb)); 635 sbuf_delete(sb); 636 exit1(td, W_EXITCODE(0, sig)); 637 return (0); 638 } 639 640 641 #ifdef COMPAT_43 642 /* 643 * The dirty work is handled by kern_wait(). 644 */ 645 int 646 owait(struct thread *td, struct owait_args *uap __unused) 647 { 648 int error, status; 649 650 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 651 if (error == 0) 652 td->td_retval[1] = status; 653 return (error); 654 } 655 #endif /* COMPAT_43 */ 656 657 /* 658 * The dirty work is handled by kern_wait(). 659 */ 660 int 661 wait4(struct thread *td, struct wait_args *uap) 662 { 663 struct rusage ru, *rup; 664 int error, status; 665 666 if (uap->rusage != NULL) 667 rup = &ru; 668 else 669 rup = NULL; 670 error = kern_wait(td, uap->pid, &status, uap->options, rup); 671 if (uap->status != NULL && error == 0) 672 error = copyout(&status, uap->status, sizeof(status)); 673 if (uap->rusage != NULL && error == 0) 674 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 675 return (error); 676 } 677 678 int 679 kern_wait(struct thread *td, pid_t pid, int *status, int options, 680 struct rusage *rusage) 681 { 682 struct proc *p, *q, *t; 683 int error, nfound; 684 685 AUDIT_ARG(pid, pid); 686 687 q = td->td_proc; 688 if (pid == 0) { 689 PROC_LOCK(q); 690 pid = -q->p_pgid; 691 PROC_UNLOCK(q); 692 } 693 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 694 return (EINVAL); 695 loop: 696 if (q->p_flag & P_STATCHILD) { 697 PROC_LOCK(q); 698 q->p_flag &= ~P_STATCHILD; 699 PROC_UNLOCK(q); 700 } 701 nfound = 0; 702 sx_xlock(&proctree_lock); 703 LIST_FOREACH(p, &q->p_children, p_sibling) { 704 PROC_LOCK(p); 705 if (pid != WAIT_ANY && 706 p->p_pid != pid && p->p_pgid != -pid) { 707 PROC_UNLOCK(p); 708 continue; 709 } 710 if (p_canwait(td, p)) { 711 PROC_UNLOCK(p); 712 continue; 713 } 714 715 /* 716 * This special case handles a kthread spawned by linux_clone 717 * (see linux_misc.c). The linux_wait4 and linux_waitpid 718 * functions need to be able to distinguish between waiting 719 * on a process and waiting on a thread. It is a thread if 720 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 721 * signifies we want to wait for threads and not processes. 722 */ 723 if ((p->p_sigparent != SIGCHLD) ^ 724 ((options & WLINUXCLONE) != 0)) { 725 PROC_UNLOCK(p); 726 continue; 727 } 728 729 nfound++; 730 PROC_SLOCK(p); 731 if (p->p_state == PRS_ZOMBIE) { 732 if (rusage) { 733 *rusage = p->p_ru; 734 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 735 } 736 PROC_SUNLOCK(p); 737 td->td_retval[0] = p->p_pid; 738 if (status) 739 *status = p->p_xstat; /* convert to int */ 740 PROC_LOCK(q); 741 sigqueue_take(p->p_ksi); 742 PROC_UNLOCK(q); 743 744 /* 745 * If we got the child via a ptrace 'attach', 746 * we need to give it back to the old parent. 747 */ 748 PROC_UNLOCK(p); 749 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 750 PROC_LOCK(p); 751 p->p_oppid = 0; 752 proc_reparent(p, t); 753 PROC_UNLOCK(p); 754 tdsignal(t, NULL, SIGCHLD, p->p_ksi); 755 wakeup(t); 756 PROC_UNLOCK(t); 757 sx_xunlock(&proctree_lock); 758 return (0); 759 } 760 761 /* 762 * Remove other references to this process to ensure 763 * we have an exclusive reference. 764 */ 765 sx_xlock(&allproc_lock); 766 LIST_REMOVE(p, p_list); /* off zombproc */ 767 sx_xunlock(&allproc_lock); 768 LIST_REMOVE(p, p_sibling); 769 leavepgrp(p); 770 sx_xunlock(&proctree_lock); 771 772 /* 773 * As a side effect of this lock, we know that 774 * all other writes to this proc are visible now, so 775 * no more locking is needed for p. 776 */ 777 PROC_LOCK(p); 778 p->p_xstat = 0; /* XXX: why? */ 779 PROC_UNLOCK(p); 780 PROC_LOCK(q); 781 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, 782 &p->p_rux); 783 PROC_UNLOCK(q); 784 785 /* 786 * Decrement the count of procs running with this uid. 787 */ 788 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 789 790 /* 791 * Free credentials, arguments, and sigacts. 792 */ 793 crfree(p->p_ucred); 794 p->p_ucred = NULL; 795 pargs_drop(p->p_args); 796 p->p_args = NULL; 797 sigacts_free(p->p_sigacts); 798 p->p_sigacts = NULL; 799 800 /* 801 * Do any thread-system specific cleanups. 802 */ 803 thread_wait(p); 804 805 /* 806 * Give vm and machine-dependent layer a chance 807 * to free anything that cpu_exit couldn't 808 * release while still running in process context. 809 */ 810 vm_waitproc(p); 811 #ifdef MAC 812 mac_proc_destroy(p); 813 #endif 814 KASSERT(FIRST_THREAD_IN_PROC(p), 815 ("kern_wait: no residual thread!")); 816 uma_zfree(proc_zone, p); 817 sx_xlock(&allproc_lock); 818 nprocs--; 819 sx_xunlock(&allproc_lock); 820 return (0); 821 } 822 if ((p->p_flag & P_STOPPED_SIG) && 823 (p->p_suspcount == p->p_numthreads) && 824 (p->p_flag & P_WAITED) == 0 && 825 (p->p_flag & P_TRACED || options & WUNTRACED)) { 826 PROC_SUNLOCK(p); 827 p->p_flag |= P_WAITED; 828 sx_xunlock(&proctree_lock); 829 td->td_retval[0] = p->p_pid; 830 if (status) 831 *status = W_STOPCODE(p->p_xstat); 832 833 PROC_LOCK(q); 834 sigqueue_take(p->p_ksi); 835 PROC_UNLOCK(q); 836 PROC_UNLOCK(p); 837 838 return (0); 839 } 840 PROC_SUNLOCK(p); 841 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 842 sx_xunlock(&proctree_lock); 843 td->td_retval[0] = p->p_pid; 844 p->p_flag &= ~P_CONTINUED; 845 846 PROC_LOCK(q); 847 sigqueue_take(p->p_ksi); 848 PROC_UNLOCK(q); 849 PROC_UNLOCK(p); 850 851 if (status) 852 *status = SIGCONT; 853 return (0); 854 } 855 PROC_UNLOCK(p); 856 } 857 if (nfound == 0) { 858 sx_xunlock(&proctree_lock); 859 return (ECHILD); 860 } 861 if (options & WNOHANG) { 862 sx_xunlock(&proctree_lock); 863 td->td_retval[0] = 0; 864 return (0); 865 } 866 PROC_LOCK(q); 867 sx_xunlock(&proctree_lock); 868 if (q->p_flag & P_STATCHILD) { 869 q->p_flag &= ~P_STATCHILD; 870 error = 0; 871 } else 872 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 873 PROC_UNLOCK(q); 874 if (error) 875 return (error); 876 goto loop; 877 } 878 879 /* 880 * Make process 'parent' the new parent of process 'child'. 881 * Must be called with an exclusive hold of proctree lock. 882 */ 883 void 884 proc_reparent(struct proc *child, struct proc *parent) 885 { 886 887 sx_assert(&proctree_lock, SX_XLOCKED); 888 PROC_LOCK_ASSERT(child, MA_OWNED); 889 if (child->p_pptr == parent) 890 return; 891 892 PROC_LOCK(child->p_pptr); 893 sigqueue_take(child->p_ksi); 894 PROC_UNLOCK(child->p_pptr); 895 LIST_REMOVE(child, p_sibling); 896 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 897 child->p_pptr = parent; 898 } 899