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 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/jail.h> 55 #include <sys/tty.h> 56 #include <sys/wait.h> 57 #include <sys/vmmeter.h> 58 #include <sys/vnode.h> 59 #include <sys/racct.h> 60 #include <sys/resourcevar.h> 61 #include <sys/sbuf.h> 62 #include <sys/signalvar.h> 63 #include <sys/sched.h> 64 #include <sys/sx.h> 65 #include <sys/syscallsubr.h> 66 #include <sys/syslog.h> 67 #include <sys/ptrace.h> 68 #include <sys/acct.h> /* for acct_process() function prototype */ 69 #include <sys/filedesc.h> 70 #include <sys/sdt.h> 71 #include <sys/shm.h> 72 #include <sys/sem.h> 73 #ifdef KTRACE 74 #include <sys/ktrace.h> 75 #endif 76 77 #include <security/audit/audit.h> 78 #include <security/mac/mac_framework.h> 79 80 #include <vm/vm.h> 81 #include <vm/vm_extern.h> 82 #include <vm/vm_param.h> 83 #include <vm/pmap.h> 84 #include <vm/vm_map.h> 85 #include <vm/vm_page.h> 86 #include <vm/uma.h> 87 88 #ifdef KDTRACE_HOOKS 89 #include <sys/dtrace_bsd.h> 90 dtrace_execexit_func_t dtrace_fasttrap_exit; 91 #endif 92 93 SDT_PROVIDER_DECLARE(proc); 94 SDT_PROBE_DEFINE(proc, kernel, , exit, exit); 95 SDT_PROBE_ARGTYPE(proc, kernel, , exit, 0, "int"); 96 97 /* Hook for NFS teardown procedure. */ 98 void (*nlminfo_release_p)(struct proc *p); 99 100 /* 101 * exit -- death of process. 102 */ 103 void 104 sys_exit(struct thread *td, struct sys_exit_args *uap) 105 { 106 107 exit1(td, W_EXITCODE(uap->rval, 0)); 108 /* NOTREACHED */ 109 } 110 111 /* 112 * Exit: deallocate address space and other resources, change proc state to 113 * zombie, and unlink proc from allproc and parent's lists. Save exit status 114 * and rusage for wait(). Check for child processes and orphan them. 115 */ 116 void 117 exit1(struct thread *td, int rv) 118 { 119 struct proc *p, *nq, *q; 120 struct vnode *vtmp; 121 struct vnode *ttyvp = NULL; 122 struct plimit *plim; 123 int locked; 124 125 mtx_assert(&Giant, MA_NOTOWNED); 126 127 p = td->td_proc; 128 /* 129 * XXX in case we're rebooting we just let init die in order to 130 * work around an unsolved stack overflow seen very late during 131 * shutdown on sparc64 when the gmirror worker process exists. 132 */ 133 if (p == initproc && rebooting == 0) { 134 printf("init died (signal %d, exit %d)\n", 135 WTERMSIG(rv), WEXITSTATUS(rv)); 136 panic("Going nowhere without my init!"); 137 } 138 139 /* 140 * MUST abort all other threads before proceeding past here. 141 */ 142 PROC_LOCK(p); 143 while (p->p_flag & P_HADTHREADS) { 144 /* 145 * First check if some other thread got here before us.. 146 * if so, act apropriatly, (exit or suspend); 147 */ 148 thread_suspend_check(0); 149 150 /* 151 * Kill off the other threads. This requires 152 * some co-operation from other parts of the kernel 153 * so it may not be instantaneous. With this state set 154 * any thread entering the kernel from userspace will 155 * thread_exit() in trap(). Any thread attempting to 156 * sleep will return immediately with EINTR or EWOULDBLOCK 157 * which will hopefully force them to back out to userland 158 * freeing resources as they go. Any thread attempting 159 * to return to userland will thread_exit() from userret(). 160 * thread_exit() will unsuspend us when the last of the 161 * other threads exits. 162 * If there is already a thread singler after resumption, 163 * calling thread_single will fail; in that case, we just 164 * re-check all suspension request, the thread should 165 * either be suspended there or exit. 166 */ 167 if (! thread_single(SINGLE_EXIT)) 168 break; 169 170 /* 171 * All other activity in this process is now stopped. 172 * Threading support has been turned off. 173 */ 174 } 175 KASSERT(p->p_numthreads == 1, 176 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 177 racct_sub(p, RACCT_NTHR, 1); 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 p->p_xstat = rv; /* Let event handler change exit status */ 203 PROC_UNLOCK(p); 204 /* Drain the limit callout while we don't have the proc locked */ 205 callout_drain(&p->p_limco); 206 207 #ifdef AUDIT 208 /* 209 * The Sun BSM exit token contains two components: an exit status as 210 * passed to exit(), and a return value to indicate what sort of exit 211 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 212 * what the return value is. 213 */ 214 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0); 215 AUDIT_SYSCALL_EXIT(0, td); 216 #endif 217 218 /* Are we a task leader? */ 219 if (p == p->p_leader) { 220 mtx_lock(&ppeers_lock); 221 q = p->p_peers; 222 while (q != NULL) { 223 PROC_LOCK(q); 224 psignal(q, SIGKILL); 225 PROC_UNLOCK(q); 226 q = q->p_peers; 227 } 228 while (p->p_peers != NULL) 229 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 230 mtx_unlock(&ppeers_lock); 231 } 232 233 /* 234 * Check if any loadable modules need anything done at process exit. 235 * E.g. SYSV IPC stuff 236 * XXX what if one of these generates an error? 237 */ 238 EVENTHANDLER_INVOKE(process_exit, p); 239 240 /* 241 * If parent is waiting for us to exit or exec, 242 * P_PPWAIT is set; we will wakeup the parent below. 243 */ 244 PROC_LOCK(p); 245 rv = p->p_xstat; /* Event handler could change exit status */ 246 stopprofclock(p); 247 p->p_flag &= ~(P_TRACED | P_PPWAIT); 248 249 /* 250 * Stop the real interval timer. If the handler is currently 251 * executing, prevent it from rearming itself and let it finish. 252 */ 253 if (timevalisset(&p->p_realtimer.it_value) && 254 callout_stop(&p->p_itcallout) == 0) { 255 timevalclear(&p->p_realtimer.it_interval); 256 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 257 KASSERT(!timevalisset(&p->p_realtimer.it_value), 258 ("realtime timer is still armed")); 259 } 260 PROC_UNLOCK(p); 261 262 /* 263 * Reset any sigio structures pointing to us as a result of 264 * F_SETOWN with our pid. 265 */ 266 funsetownlst(&p->p_sigiolst); 267 268 /* 269 * If this process has an nlminfo data area (for lockd), release it 270 */ 271 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 272 (*nlminfo_release_p)(p); 273 274 /* 275 * Close open files and release open-file table. 276 * This may block! 277 */ 278 fdfree(td); 279 280 /* 281 * If this thread tickled GEOM, we need to wait for the giggling to 282 * stop before we return to userland 283 */ 284 if (td->td_pflags & TDP_GEOM) 285 g_waitidle(); 286 287 /* 288 * Remove ourself from our leader's peer list and wake our leader. 289 */ 290 mtx_lock(&ppeers_lock); 291 if (p->p_leader->p_peers) { 292 q = p->p_leader; 293 while (q->p_peers != p) 294 q = q->p_peers; 295 q->p_peers = p->p_peers; 296 wakeup(p->p_leader); 297 } 298 mtx_unlock(&ppeers_lock); 299 300 vmspace_exit(td); 301 302 sx_xlock(&proctree_lock); 303 if (SESS_LEADER(p)) { 304 struct session *sp = p->p_session; 305 struct tty *tp; 306 307 /* 308 * s_ttyp is not zero'd; we use this to indicate that 309 * the session once had a controlling terminal. (for 310 * logging and informational purposes) 311 */ 312 SESS_LOCK(sp); 313 ttyvp = sp->s_ttyvp; 314 tp = sp->s_ttyp; 315 sp->s_ttyvp = NULL; 316 sp->s_ttydp = NULL; 317 sp->s_leader = NULL; 318 SESS_UNLOCK(sp); 319 320 /* 321 * Signal foreground pgrp and revoke access to 322 * controlling terminal if it has not been revoked 323 * already. 324 * 325 * Because the TTY may have been revoked in the mean 326 * time and could already have a new session associated 327 * with it, make sure we don't send a SIGHUP to a 328 * foreground process group that does not belong to this 329 * session. 330 */ 331 332 if (tp != NULL) { 333 tty_lock(tp); 334 if (tp->t_session == sp) 335 tty_signal_pgrp(tp, SIGHUP); 336 tty_unlock(tp); 337 } 338 339 if (ttyvp != NULL) { 340 sx_xunlock(&proctree_lock); 341 if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) { 342 VOP_REVOKE(ttyvp, REVOKEALL); 343 VOP_UNLOCK(ttyvp, 0); 344 } 345 sx_xlock(&proctree_lock); 346 } 347 } 348 fixjobc(p, p->p_pgrp, 0); 349 sx_xunlock(&proctree_lock); 350 (void)acct_process(td); 351 352 /* Release the TTY now we've unlocked everything. */ 353 if (ttyvp != NULL) 354 vrele(ttyvp); 355 #ifdef KTRACE 356 ktrprocexit(td); 357 #endif 358 /* 359 * Release reference to text vnode 360 */ 361 if ((vtmp = p->p_textvp) != NULL) { 362 p->p_textvp = NULL; 363 locked = VFS_LOCK_GIANT(vtmp->v_mount); 364 vrele(vtmp); 365 VFS_UNLOCK_GIANT(locked); 366 } 367 368 /* 369 * Release our limits structure. 370 */ 371 PROC_LOCK(p); 372 plim = p->p_limit; 373 p->p_limit = NULL; 374 PROC_UNLOCK(p); 375 lim_free(plim); 376 377 tidhash_remove(td); 378 379 /* 380 * Remove proc from allproc queue and pidhash chain. 381 * Place onto zombproc. Unlink from parent's child list. 382 */ 383 sx_xlock(&allproc_lock); 384 LIST_REMOVE(p, p_list); 385 LIST_INSERT_HEAD(&zombproc, p, p_list); 386 LIST_REMOVE(p, p_hash); 387 sx_xunlock(&allproc_lock); 388 389 /* 390 * Call machine-dependent code to release any 391 * machine-dependent resources other than the address space. 392 * The address space is released by "vmspace_exitfree(p)" in 393 * vm_waitproc(). 394 */ 395 cpu_exit(td); 396 397 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 398 399 /* 400 * Reparent all of our children to init. 401 */ 402 sx_xlock(&proctree_lock); 403 q = LIST_FIRST(&p->p_children); 404 if (q != NULL) /* only need this if any child is S_ZOMB */ 405 wakeup(initproc); 406 for (; q != NULL; q = nq) { 407 nq = LIST_NEXT(q, p_sibling); 408 PROC_LOCK(q); 409 proc_reparent(q, initproc); 410 q->p_sigparent = SIGCHLD; 411 /* 412 * Traced processes are killed 413 * since their existence means someone is screwing up. 414 */ 415 if (q->p_flag & P_TRACED) { 416 struct thread *temp; 417 418 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 419 FOREACH_THREAD_IN_PROC(q, temp) 420 temp->td_dbgflags &= ~TDB_SUSPEND; 421 psignal(q, SIGKILL); 422 } 423 PROC_UNLOCK(q); 424 } 425 426 /* Save exit status. */ 427 PROC_LOCK(p); 428 p->p_xthread = td; 429 430 /* Tell the prison that we are gone. */ 431 prison_proc_free(p->p_ucred->cr_prison); 432 433 #ifdef KDTRACE_HOOKS 434 /* 435 * Tell the DTrace fasttrap provider about the exit if it 436 * has declared an interest. 437 */ 438 if (dtrace_fasttrap_exit) 439 dtrace_fasttrap_exit(p); 440 #endif 441 442 /* 443 * Notify interested parties of our demise. 444 */ 445 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 446 447 #ifdef KDTRACE_HOOKS 448 int reason = CLD_EXITED; 449 if (WCOREDUMP(rv)) 450 reason = CLD_DUMPED; 451 else if (WIFSIGNALED(rv)) 452 reason = CLD_KILLED; 453 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 454 #endif 455 456 /* 457 * Just delete all entries in the p_klist. At this point we won't 458 * report any more events, and there are nasty race conditions that 459 * can beat us if we don't. 460 */ 461 knlist_clear(&p->p_klist, 1); 462 463 /* 464 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 465 * flag set, or if the handler is set to SIG_IGN, notify process 466 * 1 instead (and hope it will handle this situation). 467 */ 468 PROC_LOCK(p->p_pptr); 469 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 470 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 471 struct proc *pp; 472 473 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 474 pp = p->p_pptr; 475 PROC_UNLOCK(pp); 476 proc_reparent(p, initproc); 477 p->p_sigparent = SIGCHLD; 478 PROC_LOCK(p->p_pptr); 479 480 /* 481 * Notify parent, so in case he was wait(2)ing or 482 * executing waitpid(2) with our pid, he will 483 * continue. 484 */ 485 wakeup(pp); 486 } else 487 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 488 489 if (p->p_pptr == initproc) 490 psignal(p->p_pptr, SIGCHLD); 491 else if (p->p_sigparent != 0) { 492 if (p->p_sigparent == SIGCHLD) 493 childproc_exited(p); 494 else /* LINUX thread */ 495 psignal(p->p_pptr, p->p_sigparent); 496 } 497 sx_xunlock(&proctree_lock); 498 499 /* 500 * The state PRS_ZOMBIE prevents other proesses from sending 501 * signal to the process, to avoid memory leak, we free memory 502 * for signal queue at the time when the state is set. 503 */ 504 sigqueue_flush(&p->p_sigqueue); 505 sigqueue_flush(&td->td_sigqueue); 506 507 /* 508 * We have to wait until after acquiring all locks before 509 * changing p_state. We need to avoid all possible context 510 * switches (including ones from blocking on a mutex) while 511 * marked as a zombie. We also have to set the zombie state 512 * before we release the parent process' proc lock to avoid 513 * a lost wakeup. So, we first call wakeup, then we grab the 514 * sched lock, update the state, and release the parent process' 515 * proc lock. 516 */ 517 wakeup(p->p_pptr); 518 cv_broadcast(&p->p_pwait); 519 sched_exit(p->p_pptr, td); 520 PROC_SLOCK(p); 521 p->p_state = PRS_ZOMBIE; 522 PROC_UNLOCK(p->p_pptr); 523 524 /* 525 * Hopefully no one will try to deliver a signal to the process this 526 * late in the game. 527 */ 528 knlist_destroy(&p->p_klist); 529 530 /* 531 * Save our children's rusage information in our exit rusage. 532 */ 533 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 534 535 /* 536 * Make sure the scheduler takes this thread out of its tables etc. 537 * This will also release this thread's reference to the ucred. 538 * Other thread parts to release include pcb bits and such. 539 */ 540 thread_exit(); 541 } 542 543 544 #ifndef _SYS_SYSPROTO_H_ 545 struct abort2_args { 546 char *why; 547 int nargs; 548 void **args; 549 }; 550 #endif 551 552 int 553 abort2(struct thread *td, struct abort2_args *uap) 554 { 555 struct proc *p = td->td_proc; 556 struct sbuf *sb; 557 void *uargs[16]; 558 int error, i, sig; 559 560 /* 561 * Do it right now so we can log either proper call of abort2(), or 562 * note, that invalid argument was passed. 512 is big enough to 563 * handle 16 arguments' descriptions with additional comments. 564 */ 565 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 566 sbuf_clear(sb); 567 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 568 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 569 /* 570 * Since we can't return from abort2(), send SIGKILL in cases, where 571 * abort2() was called improperly 572 */ 573 sig = SIGKILL; 574 /* Prevent from DoSes from user-space. */ 575 if (uap->nargs < 0 || uap->nargs > 16) 576 goto out; 577 if (uap->nargs > 0) { 578 if (uap->args == NULL) 579 goto out; 580 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 581 if (error != 0) 582 goto out; 583 } 584 /* 585 * Limit size of 'reason' string to 128. Will fit even when 586 * maximal number of arguments was chosen to be logged. 587 */ 588 if (uap->why != NULL) { 589 error = sbuf_copyin(sb, uap->why, 128); 590 if (error < 0) 591 goto out; 592 } else { 593 sbuf_printf(sb, "(null)"); 594 } 595 if (uap->nargs > 0) { 596 sbuf_printf(sb, "("); 597 for (i = 0;i < uap->nargs; i++) 598 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 599 sbuf_printf(sb, ")"); 600 } 601 /* 602 * Final stage: arguments were proper, string has been 603 * successfully copied from userspace, and copying pointers 604 * from user-space succeed. 605 */ 606 sig = SIGABRT; 607 out: 608 if (sig == SIGKILL) { 609 sbuf_trim(sb); 610 sbuf_printf(sb, " (Reason text inaccessible)"); 611 } 612 sbuf_cat(sb, "\n"); 613 sbuf_finish(sb); 614 log(LOG_INFO, "%s", sbuf_data(sb)); 615 sbuf_delete(sb); 616 exit1(td, W_EXITCODE(0, sig)); 617 return (0); 618 } 619 620 621 #ifdef COMPAT_43 622 /* 623 * The dirty work is handled by kern_wait(). 624 */ 625 int 626 owait(struct thread *td, struct owait_args *uap __unused) 627 { 628 int error, status; 629 630 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 631 if (error == 0) 632 td->td_retval[1] = status; 633 return (error); 634 } 635 #endif /* COMPAT_43 */ 636 637 /* 638 * The dirty work is handled by kern_wait(). 639 */ 640 int 641 wait4(struct thread *td, struct wait_args *uap) 642 { 643 struct rusage ru, *rup; 644 int error, status; 645 646 if (uap->rusage != NULL) 647 rup = &ru; 648 else 649 rup = NULL; 650 error = kern_wait(td, uap->pid, &status, uap->options, rup); 651 if (uap->status != NULL && error == 0) 652 error = copyout(&status, uap->status, sizeof(status)); 653 if (uap->rusage != NULL && error == 0) 654 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 655 return (error); 656 } 657 658 /* 659 * Reap the remains of a zombie process and optionally return status and 660 * rusage. Asserts and will release both the proctree_lock and the process 661 * lock as part of its work. 662 */ 663 static void 664 proc_reap(struct thread *td, struct proc *p, int *status, int options, 665 struct rusage *rusage) 666 { 667 struct proc *q, *t; 668 669 sx_assert(&proctree_lock, SA_XLOCKED); 670 PROC_LOCK_ASSERT(p, MA_OWNED); 671 PROC_SLOCK_ASSERT(p, MA_OWNED); 672 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 673 674 q = td->td_proc; 675 if (rusage) { 676 *rusage = p->p_ru; 677 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 678 } 679 PROC_SUNLOCK(p); 680 td->td_retval[0] = p->p_pid; 681 if (status) 682 *status = p->p_xstat; /* convert to int */ 683 if (options & WNOWAIT) { 684 /* 685 * Only poll, returning the status. Caller does not wish to 686 * release the proc struct just yet. 687 */ 688 PROC_UNLOCK(p); 689 sx_xunlock(&proctree_lock); 690 return; 691 } 692 693 PROC_LOCK(q); 694 sigqueue_take(p->p_ksi); 695 PROC_UNLOCK(q); 696 PROC_UNLOCK(p); 697 698 /* 699 * If we got the child via a ptrace 'attach', we need to give it back 700 * to the old parent. 701 */ 702 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 703 PROC_LOCK(p); 704 p->p_oppid = 0; 705 proc_reparent(p, t); 706 PROC_UNLOCK(p); 707 pksignal(t, SIGCHLD, p->p_ksi); 708 wakeup(t); 709 cv_broadcast(&p->p_pwait); 710 PROC_UNLOCK(t); 711 sx_xunlock(&proctree_lock); 712 return; 713 } 714 715 /* 716 * Remove other references to this process to ensure we have an 717 * exclusive reference. 718 */ 719 sx_xlock(&allproc_lock); 720 LIST_REMOVE(p, p_list); /* off zombproc */ 721 sx_xunlock(&allproc_lock); 722 LIST_REMOVE(p, p_sibling); 723 leavepgrp(p); 724 sx_xunlock(&proctree_lock); 725 726 /* 727 * As a side effect of this lock, we know that all other writes to 728 * this proc are visible now, so no more locking is needed for p. 729 */ 730 PROC_LOCK(p); 731 p->p_xstat = 0; /* XXX: why? */ 732 PROC_UNLOCK(p); 733 PROC_LOCK(q); 734 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 735 PROC_UNLOCK(q); 736 737 /* 738 * Decrement the count of procs running with this uid. 739 */ 740 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 741 742 /* 743 * Destroy resource accounting information associated with the process. 744 */ 745 racct_proc_exit(p); 746 PROC_LOCK(p->p_pptr); 747 racct_sub(p->p_pptr, RACCT_NPROC, 1); 748 PROC_UNLOCK(p->p_pptr); 749 750 /* 751 * Free credentials, arguments, and sigacts. 752 */ 753 crfree(p->p_ucred); 754 p->p_ucred = NULL; 755 pargs_drop(p->p_args); 756 p->p_args = NULL; 757 sigacts_free(p->p_sigacts); 758 p->p_sigacts = NULL; 759 760 /* 761 * Do any thread-system specific cleanups. 762 */ 763 thread_wait(p); 764 765 /* 766 * Give vm and machine-dependent layer a chance to free anything that 767 * cpu_exit couldn't release while still running in process context. 768 */ 769 vm_waitproc(p); 770 #ifdef MAC 771 mac_proc_destroy(p); 772 #endif 773 KASSERT(FIRST_THREAD_IN_PROC(p), 774 ("proc_reap: no residual thread!")); 775 uma_zfree(proc_zone, p); 776 sx_xlock(&allproc_lock); 777 nprocs--; 778 sx_xunlock(&allproc_lock); 779 } 780 781 int 782 kern_wait(struct thread *td, pid_t pid, int *status, int options, 783 struct rusage *rusage) 784 { 785 struct proc *p, *q; 786 int error, nfound; 787 788 AUDIT_ARG_PID(pid); 789 AUDIT_ARG_VALUE(options); 790 791 q = td->td_proc; 792 if (pid == 0) { 793 PROC_LOCK(q); 794 pid = -q->p_pgid; 795 PROC_UNLOCK(q); 796 } 797 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE)) 798 return (EINVAL); 799 loop: 800 if (q->p_flag & P_STATCHILD) { 801 PROC_LOCK(q); 802 q->p_flag &= ~P_STATCHILD; 803 PROC_UNLOCK(q); 804 } 805 nfound = 0; 806 sx_xlock(&proctree_lock); 807 LIST_FOREACH(p, &q->p_children, p_sibling) { 808 PROC_LOCK(p); 809 if (pid != WAIT_ANY && 810 p->p_pid != pid && p->p_pgid != -pid) { 811 PROC_UNLOCK(p); 812 continue; 813 } 814 if (p_canwait(td, p)) { 815 PROC_UNLOCK(p); 816 continue; 817 } 818 819 /* 820 * This special case handles a kthread spawned by linux_clone 821 * (see linux_misc.c). The linux_wait4 and linux_waitpid 822 * functions need to be able to distinguish between waiting 823 * on a process and waiting on a thread. It is a thread if 824 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 825 * signifies we want to wait for threads and not processes. 826 */ 827 if ((p->p_sigparent != SIGCHLD) ^ 828 ((options & WLINUXCLONE) != 0)) { 829 PROC_UNLOCK(p); 830 continue; 831 } 832 833 nfound++; 834 PROC_SLOCK(p); 835 if (p->p_state == PRS_ZOMBIE) { 836 proc_reap(td, p, status, options, rusage); 837 return (0); 838 } 839 if ((p->p_flag & P_STOPPED_SIG) && 840 (p->p_suspcount == p->p_numthreads) && 841 (p->p_flag & P_WAITED) == 0 && 842 (p->p_flag & P_TRACED || options & WUNTRACED)) { 843 PROC_SUNLOCK(p); 844 p->p_flag |= P_WAITED; 845 sx_xunlock(&proctree_lock); 846 td->td_retval[0] = p->p_pid; 847 if (status) 848 *status = W_STOPCODE(p->p_xstat); 849 850 PROC_LOCK(q); 851 sigqueue_take(p->p_ksi); 852 PROC_UNLOCK(q); 853 PROC_UNLOCK(p); 854 855 return (0); 856 } 857 PROC_SUNLOCK(p); 858 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 859 sx_xunlock(&proctree_lock); 860 td->td_retval[0] = p->p_pid; 861 p->p_flag &= ~P_CONTINUED; 862 863 PROC_LOCK(q); 864 sigqueue_take(p->p_ksi); 865 PROC_UNLOCK(q); 866 PROC_UNLOCK(p); 867 868 if (status) 869 *status = SIGCONT; 870 return (0); 871 } 872 PROC_UNLOCK(p); 873 } 874 if (nfound == 0) { 875 sx_xunlock(&proctree_lock); 876 return (ECHILD); 877 } 878 if (options & WNOHANG) { 879 sx_xunlock(&proctree_lock); 880 td->td_retval[0] = 0; 881 return (0); 882 } 883 PROC_LOCK(q); 884 sx_xunlock(&proctree_lock); 885 if (q->p_flag & P_STATCHILD) { 886 q->p_flag &= ~P_STATCHILD; 887 error = 0; 888 } else 889 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 890 PROC_UNLOCK(q); 891 if (error) 892 return (error); 893 goto loop; 894 } 895 896 /* 897 * Make process 'parent' the new parent of process 'child'. 898 * Must be called with an exclusive hold of proctree lock. 899 */ 900 void 901 proc_reparent(struct proc *child, struct proc *parent) 902 { 903 int locked; 904 905 sx_assert(&proctree_lock, SX_XLOCKED); 906 PROC_LOCK_ASSERT(child, MA_OWNED); 907 if (child->p_pptr == parent) 908 return; 909 910 locked = PROC_LOCKED(parent); 911 if (!locked) 912 PROC_LOCK(parent); 913 racct_add_force(parent, RACCT_NPROC, 1); 914 if (!locked) 915 PROC_UNLOCK(parent); 916 PROC_LOCK(child->p_pptr); 917 racct_sub(child->p_pptr, RACCT_NPROC, 1); 918 sigqueue_take(child->p_ksi); 919 PROC_UNLOCK(child->p_pptr); 920 LIST_REMOVE(child, p_sibling); 921 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 922 child->p_pptr = parent; 923 } 924