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/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 /* 135 * XXX in case we're rebooting we just let init die in order to 136 * work around an unsolved stack overflow seen very late during 137 * shutdown on sparc64 when the gmirror worker process exists. 138 */ 139 if (p == initproc && rebooting == 0) { 140 printf("init died (signal %d, exit %d)\n", 141 WTERMSIG(rv), WEXITSTATUS(rv)); 142 panic("Going nowhere without my init!"); 143 } 144 145 /* 146 * MUST abort all other threads before proceeding past here. 147 */ 148 PROC_LOCK(p); 149 while (p->p_flag & P_HADTHREADS) { 150 /* 151 * First check if some other thread got here before us.. 152 * if so, act apropriatly, (exit or suspend); 153 */ 154 thread_suspend_check(0); 155 156 /* 157 * Kill off the other threads. This requires 158 * some co-operation from other parts of the kernel 159 * so it may not be instantaneous. With this state set 160 * any thread entering the kernel from userspace will 161 * thread_exit() in trap(). Any thread attempting to 162 * sleep will return immediately with EINTR or EWOULDBLOCK 163 * which will hopefully force them to back out to userland 164 * freeing resources as they go. Any thread attempting 165 * to return to userland will thread_exit() from userret(). 166 * thread_exit() will unsuspend us when the last of the 167 * other threads exits. 168 * If there is already a thread singler after resumption, 169 * calling thread_single will fail; in that case, we just 170 * re-check all suspension request, the thread should 171 * either be suspended there or exit. 172 */ 173 if (! thread_single(SINGLE_EXIT)) 174 break; 175 176 /* 177 * All other activity in this process is now stopped. 178 * Threading support has been turned off. 179 */ 180 } 181 KASSERT(p->p_numthreads == 1, 182 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 183 /* 184 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 185 * on our vmspace, so we should block below until they have 186 * released their reference to us. Note that if they have 187 * requested S_EXIT stops we will block here until they ack 188 * via PIOCCONT. 189 */ 190 _STOPEVENT(p, S_EXIT, rv); 191 192 /* 193 * Note that we are exiting and do another wakeup of anyone in 194 * PIOCWAIT in case they aren't listening for S_EXIT stops or 195 * decided to wait again after we told them we are exiting. 196 */ 197 p->p_flag |= P_WEXIT; 198 wakeup(&p->p_stype); 199 200 /* 201 * Wait for any processes that have a hold on our vmspace to 202 * release their reference. 203 */ 204 while (p->p_lock > 0) 205 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 206 207 PROC_UNLOCK(p); 208 /* Drain the limit callout while we don't have the proc locked */ 209 callout_drain(&p->p_limco); 210 211 #ifdef AUDIT 212 /* 213 * The Sun BSM exit token contains two components: an exit status as 214 * passed to exit(), and a return value to indicate what sort of exit 215 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 216 * what the return value is. 217 */ 218 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0); 219 AUDIT_SYSCALL_EXIT(0, td); 220 #endif 221 222 /* Are we a task leader? */ 223 if (p == p->p_leader) { 224 mtx_lock(&ppeers_lock); 225 q = p->p_peers; 226 while (q != NULL) { 227 PROC_LOCK(q); 228 psignal(q, SIGKILL); 229 PROC_UNLOCK(q); 230 q = q->p_peers; 231 } 232 while (p->p_peers != NULL) 233 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 234 mtx_unlock(&ppeers_lock); 235 } 236 237 /* 238 * Check if any loadable modules need anything done at process exit. 239 * E.g. SYSV IPC stuff 240 * XXX what if one of these generates an error? 241 */ 242 EVENTHANDLER_INVOKE(process_exit, p); 243 244 /* 245 * If parent is waiting for us to exit or exec, 246 * P_PPWAIT is set; we will wakeup the parent below. 247 */ 248 PROC_LOCK(p); 249 stopprofclock(p); 250 p->p_flag &= ~(P_TRACED | P_PPWAIT); 251 252 /* 253 * Stop the real interval timer. If the handler is currently 254 * executing, prevent it from rearming itself and let it finish. 255 */ 256 if (timevalisset(&p->p_realtimer.it_value) && 257 callout_stop(&p->p_itcallout) == 0) { 258 timevalclear(&p->p_realtimer.it_interval); 259 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 260 KASSERT(!timevalisset(&p->p_realtimer.it_value), 261 ("realtime timer is still armed")); 262 } 263 PROC_UNLOCK(p); 264 265 /* 266 * Reset any sigio structures pointing to us as a result of 267 * F_SETOWN with our pid. 268 */ 269 funsetownlst(&p->p_sigiolst); 270 271 /* 272 * If this process has an nlminfo data area (for lockd), release it 273 */ 274 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 275 (*nlminfo_release_p)(p); 276 277 /* 278 * Close open files and release open-file table. 279 * This may block! 280 */ 281 fdfree(td); 282 283 /* 284 * If this thread tickled GEOM, we need to wait for the giggling to 285 * stop before we return to userland 286 */ 287 if (td->td_pflags & TDP_GEOM) 288 g_waitidle(); 289 290 /* 291 * Remove ourself from our leader's peer list and wake our leader. 292 */ 293 mtx_lock(&ppeers_lock); 294 if (p->p_leader->p_peers) { 295 q = p->p_leader; 296 while (q->p_peers != p) 297 q = q->p_peers; 298 q->p_peers = p->p_peers; 299 wakeup(p->p_leader); 300 } 301 mtx_unlock(&ppeers_lock); 302 303 vmspace_exit(td); 304 305 sx_xlock(&proctree_lock); 306 if (SESS_LEADER(p)) { 307 struct session *sp = p->p_session; 308 struct tty *tp; 309 310 /* 311 * s_ttyp is not zero'd; we use this to indicate that 312 * the session once had a controlling terminal. (for 313 * logging and informational purposes) 314 */ 315 SESS_LOCK(sp); 316 ttyvp = sp->s_ttyvp; 317 tp = sp->s_ttyp; 318 sp->s_ttyvp = NULL; 319 sp->s_ttydp = NULL; 320 sp->s_leader = NULL; 321 SESS_UNLOCK(sp); 322 323 /* 324 * Signal foreground pgrp and revoke access to 325 * controlling terminal if it has not been revoked 326 * already. 327 * 328 * Because the TTY may have been revoked in the mean 329 * time and could already have a new session associated 330 * with it, make sure we don't send a SIGHUP to a 331 * foreground process group that does not belong to this 332 * session. 333 */ 334 335 if (tp != NULL) { 336 tty_lock(tp); 337 if (tp->t_session == sp) 338 tty_signal_pgrp(tp, SIGHUP); 339 tty_unlock(tp); 340 } 341 342 if (ttyvp != NULL) { 343 sx_xunlock(&proctree_lock); 344 if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) { 345 VOP_REVOKE(ttyvp, REVOKEALL); 346 VOP_UNLOCK(ttyvp, 0); 347 } 348 sx_xlock(&proctree_lock); 349 } 350 } 351 fixjobc(p, p->p_pgrp, 0); 352 sx_xunlock(&proctree_lock); 353 (void)acct_process(td); 354 355 /* Release the TTY now we've unlocked everything. */ 356 if (ttyvp != NULL) 357 vrele(ttyvp); 358 #ifdef KTRACE 359 /* 360 * Disable tracing, then drain any pending records and release 361 * the trace file. 362 */ 363 if (p->p_traceflag != 0) { 364 PROC_LOCK(p); 365 mtx_lock(&ktrace_mtx); 366 p->p_traceflag = 0; 367 mtx_unlock(&ktrace_mtx); 368 PROC_UNLOCK(p); 369 ktrprocexit(td); 370 PROC_LOCK(p); 371 mtx_lock(&ktrace_mtx); 372 tracevp = p->p_tracevp; 373 p->p_tracevp = NULL; 374 tracecred = p->p_tracecred; 375 p->p_tracecred = NULL; 376 mtx_unlock(&ktrace_mtx); 377 PROC_UNLOCK(p); 378 if (tracevp != NULL) { 379 locked = VFS_LOCK_GIANT(tracevp->v_mount); 380 vrele(tracevp); 381 VFS_UNLOCK_GIANT(locked); 382 } 383 if (tracecred != NULL) 384 crfree(tracecred); 385 } 386 #endif 387 /* 388 * Release reference to text vnode 389 */ 390 if ((vtmp = p->p_textvp) != NULL) { 391 p->p_textvp = NULL; 392 locked = VFS_LOCK_GIANT(vtmp->v_mount); 393 vrele(vtmp); 394 VFS_UNLOCK_GIANT(locked); 395 } 396 397 /* 398 * Release our limits structure. 399 */ 400 PROC_LOCK(p); 401 plim = p->p_limit; 402 p->p_limit = NULL; 403 PROC_UNLOCK(p); 404 lim_free(plim); 405 406 /* 407 * Remove proc from allproc queue and pidhash chain. 408 * Place onto zombproc. Unlink from parent's child list. 409 */ 410 sx_xlock(&allproc_lock); 411 LIST_REMOVE(p, p_list); 412 LIST_INSERT_HEAD(&zombproc, p, p_list); 413 LIST_REMOVE(p, p_hash); 414 sx_xunlock(&allproc_lock); 415 416 /* 417 * Call machine-dependent code to release any 418 * machine-dependent resources other than the address space. 419 * The address space is released by "vmspace_exitfree(p)" in 420 * vm_waitproc(). 421 */ 422 cpu_exit(td); 423 424 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 425 426 /* 427 * Reparent all of our children to init. 428 */ 429 sx_xlock(&proctree_lock); 430 q = LIST_FIRST(&p->p_children); 431 if (q != NULL) /* only need this if any child is S_ZOMB */ 432 wakeup(initproc); 433 for (; q != NULL; q = nq) { 434 nq = LIST_NEXT(q, p_sibling); 435 PROC_LOCK(q); 436 proc_reparent(q, initproc); 437 q->p_sigparent = SIGCHLD; 438 /* 439 * Traced processes are killed 440 * since their existence means someone is screwing up. 441 */ 442 if (q->p_flag & P_TRACED) { 443 struct thread *temp; 444 445 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 446 FOREACH_THREAD_IN_PROC(q, temp) 447 temp->td_dbgflags &= ~TDB_SUSPEND; 448 psignal(q, SIGKILL); 449 } 450 PROC_UNLOCK(q); 451 } 452 453 /* Save exit status. */ 454 PROC_LOCK(p); 455 p->p_xstat = rv; 456 p->p_xthread = td; 457 458 /* Tell the prison that we are gone. */ 459 prison_proc_free(p->p_ucred->cr_prison); 460 461 #ifdef KDTRACE_HOOKS 462 /* 463 * Tell the DTrace fasttrap provider about the exit if it 464 * has declared an interest. 465 */ 466 if (dtrace_fasttrap_exit) 467 dtrace_fasttrap_exit(p); 468 #endif 469 470 /* 471 * Notify interested parties of our demise. 472 */ 473 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 474 475 #ifdef KDTRACE_HOOKS 476 int reason = CLD_EXITED; 477 if (WCOREDUMP(rv)) 478 reason = CLD_DUMPED; 479 else if (WIFSIGNALED(rv)) 480 reason = CLD_KILLED; 481 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 482 #endif 483 484 /* 485 * Just delete all entries in the p_klist. At this point we won't 486 * report any more events, and there are nasty race conditions that 487 * can beat us if we don't. 488 */ 489 knlist_clear(&p->p_klist, 1); 490 491 /* 492 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 493 * flag set, or if the handler is set to SIG_IGN, notify process 494 * 1 instead (and hope it will handle this situation). 495 */ 496 PROC_LOCK(p->p_pptr); 497 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 498 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 499 struct proc *pp; 500 501 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 502 pp = p->p_pptr; 503 PROC_UNLOCK(pp); 504 proc_reparent(p, initproc); 505 p->p_sigparent = SIGCHLD; 506 PROC_LOCK(p->p_pptr); 507 508 /* 509 * Notify parent, so in case he was wait(2)ing or 510 * executing waitpid(2) with our pid, he will 511 * continue. 512 */ 513 wakeup(pp); 514 } else 515 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 516 517 if (p->p_pptr == initproc) 518 psignal(p->p_pptr, SIGCHLD); 519 else if (p->p_sigparent != 0) { 520 if (p->p_sigparent == SIGCHLD) 521 childproc_exited(p); 522 else /* LINUX thread */ 523 psignal(p->p_pptr, p->p_sigparent); 524 } 525 sx_xunlock(&proctree_lock); 526 527 /* 528 * The state PRS_ZOMBIE prevents other proesses from sending 529 * signal to the process, to avoid memory leak, we free memory 530 * for signal queue at the time when the state is set. 531 */ 532 sigqueue_flush(&p->p_sigqueue); 533 sigqueue_flush(&td->td_sigqueue); 534 535 /* 536 * We have to wait until after acquiring all locks before 537 * changing p_state. We need to avoid all possible context 538 * switches (including ones from blocking on a mutex) while 539 * marked as a zombie. We also have to set the zombie state 540 * before we release the parent process' proc lock to avoid 541 * a lost wakeup. So, we first call wakeup, then we grab the 542 * sched lock, update the state, and release the parent process' 543 * proc lock. 544 */ 545 wakeup(p->p_pptr); 546 cv_broadcast(&p->p_pwait); 547 sched_exit(p->p_pptr, td); 548 PROC_SLOCK(p); 549 p->p_state = PRS_ZOMBIE; 550 PROC_UNLOCK(p->p_pptr); 551 552 /* 553 * Hopefully no one will try to deliver a signal to the process this 554 * late in the game. 555 */ 556 knlist_destroy(&p->p_klist); 557 558 /* 559 * Save our children's rusage information in our exit rusage. 560 */ 561 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 562 563 /* 564 * Make sure the scheduler takes this thread out of its tables etc. 565 * This will also release this thread's reference to the ucred. 566 * Other thread parts to release include pcb bits and such. 567 */ 568 thread_exit(); 569 } 570 571 572 #ifndef _SYS_SYSPROTO_H_ 573 struct abort2_args { 574 char *why; 575 int nargs; 576 void **args; 577 }; 578 #endif 579 580 int 581 abort2(struct thread *td, struct abort2_args *uap) 582 { 583 struct proc *p = td->td_proc; 584 struct sbuf *sb; 585 void *uargs[16]; 586 int error, i, sig; 587 588 /* 589 * Do it right now so we can log either proper call of abort2(), or 590 * note, that invalid argument was passed. 512 is big enough to 591 * handle 16 arguments' descriptions with additional comments. 592 */ 593 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 594 sbuf_clear(sb); 595 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 596 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 597 /* 598 * Since we can't return from abort2(), send SIGKILL in cases, where 599 * abort2() was called improperly 600 */ 601 sig = SIGKILL; 602 /* Prevent from DoSes from user-space. */ 603 if (uap->nargs < 0 || uap->nargs > 16) 604 goto out; 605 if (uap->nargs > 0) { 606 if (uap->args == NULL) 607 goto out; 608 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 609 if (error != 0) 610 goto out; 611 } 612 /* 613 * Limit size of 'reason' string to 128. Will fit even when 614 * maximal number of arguments was chosen to be logged. 615 */ 616 if (uap->why != NULL) { 617 error = sbuf_copyin(sb, uap->why, 128); 618 if (error < 0) 619 goto out; 620 } else { 621 sbuf_printf(sb, "(null)"); 622 } 623 if (uap->nargs > 0) { 624 sbuf_printf(sb, "("); 625 for (i = 0;i < uap->nargs; i++) 626 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 627 sbuf_printf(sb, ")"); 628 } 629 /* 630 * Final stage: arguments were proper, string has been 631 * successfully copied from userspace, and copying pointers 632 * from user-space succeed. 633 */ 634 sig = SIGABRT; 635 out: 636 if (sig == SIGKILL) { 637 sbuf_trim(sb); 638 sbuf_printf(sb, " (Reason text inaccessible)"); 639 } 640 sbuf_cat(sb, "\n"); 641 sbuf_finish(sb); 642 log(LOG_INFO, "%s", sbuf_data(sb)); 643 sbuf_delete(sb); 644 exit1(td, W_EXITCODE(0, sig)); 645 return (0); 646 } 647 648 649 #ifdef COMPAT_43 650 /* 651 * The dirty work is handled by kern_wait(). 652 */ 653 int 654 owait(struct thread *td, struct owait_args *uap __unused) 655 { 656 int error, status; 657 658 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 659 if (error == 0) 660 td->td_retval[1] = status; 661 return (error); 662 } 663 #endif /* COMPAT_43 */ 664 665 /* 666 * The dirty work is handled by kern_wait(). 667 */ 668 int 669 wait4(struct thread *td, struct wait_args *uap) 670 { 671 struct rusage ru, *rup; 672 int error, status; 673 674 if (uap->rusage != NULL) 675 rup = &ru; 676 else 677 rup = NULL; 678 error = kern_wait(td, uap->pid, &status, uap->options, rup); 679 if (uap->status != NULL && error == 0) 680 error = copyout(&status, uap->status, sizeof(status)); 681 if (uap->rusage != NULL && error == 0) 682 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 683 return (error); 684 } 685 686 /* 687 * Reap the remains of a zombie process and optionally return status and 688 * rusage. Asserts and will release both the proctree_lock and the process 689 * lock as part of its work. 690 */ 691 static void 692 proc_reap(struct thread *td, struct proc *p, int *status, int options, 693 struct rusage *rusage) 694 { 695 struct proc *q, *t; 696 697 sx_assert(&proctree_lock, SA_XLOCKED); 698 PROC_LOCK_ASSERT(p, MA_OWNED); 699 PROC_SLOCK_ASSERT(p, MA_OWNED); 700 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 701 702 q = td->td_proc; 703 if (rusage) { 704 *rusage = p->p_ru; 705 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 706 } 707 PROC_SUNLOCK(p); 708 td->td_retval[0] = p->p_pid; 709 if (status) 710 *status = p->p_xstat; /* convert to int */ 711 if (options & WNOWAIT) { 712 /* 713 * Only poll, returning the status. Caller does not wish to 714 * release the proc struct just yet. 715 */ 716 PROC_UNLOCK(p); 717 sx_xunlock(&proctree_lock); 718 return; 719 } 720 721 PROC_LOCK(q); 722 sigqueue_take(p->p_ksi); 723 PROC_UNLOCK(q); 724 PROC_UNLOCK(p); 725 726 /* 727 * If we got the child via a ptrace 'attach', we need to give it back 728 * to the old parent. 729 */ 730 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 731 PROC_LOCK(p); 732 p->p_oppid = 0; 733 proc_reparent(p, t); 734 PROC_UNLOCK(p); 735 tdsignal(t, NULL, SIGCHLD, p->p_ksi); 736 wakeup(t); 737 cv_broadcast(&p->p_pwait); 738 PROC_UNLOCK(t); 739 sx_xunlock(&proctree_lock); 740 return; 741 } 742 743 /* 744 * Remove other references to this process to ensure we have an 745 * 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 all other writes to 756 * this proc are visible now, so no more locking is needed for p. 757 */ 758 PROC_LOCK(p); 759 p->p_xstat = 0; /* XXX: why? */ 760 PROC_UNLOCK(p); 761 PROC_LOCK(q); 762 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 763 PROC_UNLOCK(q); 764 765 /* 766 * Decrement the count of procs running with this uid. 767 */ 768 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 769 770 /* 771 * Free credentials, arguments, and sigacts. 772 */ 773 crfree(p->p_ucred); 774 p->p_ucred = NULL; 775 pargs_drop(p->p_args); 776 p->p_args = NULL; 777 sigacts_free(p->p_sigacts); 778 p->p_sigacts = NULL; 779 780 /* 781 * Do any thread-system specific cleanups. 782 */ 783 thread_wait(p); 784 785 /* 786 * Give vm and machine-dependent layer a chance to free anything that 787 * cpu_exit couldn't release while still running in process context. 788 */ 789 vm_waitproc(p); 790 #ifdef MAC 791 mac_proc_destroy(p); 792 #endif 793 KASSERT(FIRST_THREAD_IN_PROC(p), 794 ("proc_reap: no residual thread!")); 795 uma_zfree(proc_zone, p); 796 sx_xlock(&allproc_lock); 797 nprocs--; 798 sx_xunlock(&allproc_lock); 799 } 800 801 int 802 kern_wait(struct thread *td, pid_t pid, int *status, int options, 803 struct rusage *rusage) 804 { 805 struct proc *p, *q; 806 int error, nfound; 807 808 AUDIT_ARG_PID(pid); 809 AUDIT_ARG_VALUE(options); 810 811 q = td->td_proc; 812 if (pid == 0) { 813 PROC_LOCK(q); 814 pid = -q->p_pgid; 815 PROC_UNLOCK(q); 816 } 817 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE)) 818 return (EINVAL); 819 loop: 820 if (q->p_flag & P_STATCHILD) { 821 PROC_LOCK(q); 822 q->p_flag &= ~P_STATCHILD; 823 PROC_UNLOCK(q); 824 } 825 nfound = 0; 826 sx_xlock(&proctree_lock); 827 LIST_FOREACH(p, &q->p_children, p_sibling) { 828 PROC_LOCK(p); 829 if (pid != WAIT_ANY && 830 p->p_pid != pid && p->p_pgid != -pid) { 831 PROC_UNLOCK(p); 832 continue; 833 } 834 if (p_canwait(td, p)) { 835 PROC_UNLOCK(p); 836 continue; 837 } 838 839 /* 840 * This special case handles a kthread spawned by linux_clone 841 * (see linux_misc.c). The linux_wait4 and linux_waitpid 842 * functions need to be able to distinguish between waiting 843 * on a process and waiting on a thread. It is a thread if 844 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 845 * signifies we want to wait for threads and not processes. 846 */ 847 if ((p->p_sigparent != SIGCHLD) ^ 848 ((options & WLINUXCLONE) != 0)) { 849 PROC_UNLOCK(p); 850 continue; 851 } 852 853 nfound++; 854 PROC_SLOCK(p); 855 if (p->p_state == PRS_ZOMBIE) { 856 proc_reap(td, p, status, options, rusage); 857 return (0); 858 } 859 if ((p->p_flag & P_STOPPED_SIG) && 860 (p->p_suspcount == p->p_numthreads) && 861 (p->p_flag & P_WAITED) == 0 && 862 (p->p_flag & P_TRACED || options & WUNTRACED)) { 863 PROC_SUNLOCK(p); 864 p->p_flag |= P_WAITED; 865 sx_xunlock(&proctree_lock); 866 td->td_retval[0] = p->p_pid; 867 if (status) 868 *status = W_STOPCODE(p->p_xstat); 869 870 PROC_LOCK(q); 871 sigqueue_take(p->p_ksi); 872 PROC_UNLOCK(q); 873 PROC_UNLOCK(p); 874 875 return (0); 876 } 877 PROC_SUNLOCK(p); 878 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 879 sx_xunlock(&proctree_lock); 880 td->td_retval[0] = p->p_pid; 881 p->p_flag &= ~P_CONTINUED; 882 883 PROC_LOCK(q); 884 sigqueue_take(p->p_ksi); 885 PROC_UNLOCK(q); 886 PROC_UNLOCK(p); 887 888 if (status) 889 *status = SIGCONT; 890 return (0); 891 } 892 PROC_UNLOCK(p); 893 } 894 if (nfound == 0) { 895 sx_xunlock(&proctree_lock); 896 return (ECHILD); 897 } 898 if (options & WNOHANG) { 899 sx_xunlock(&proctree_lock); 900 td->td_retval[0] = 0; 901 return (0); 902 } 903 PROC_LOCK(q); 904 sx_xunlock(&proctree_lock); 905 if (q->p_flag & P_STATCHILD) { 906 q->p_flag &= ~P_STATCHILD; 907 error = 0; 908 } else 909 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 910 PROC_UNLOCK(q); 911 if (error) 912 return (error); 913 goto loop; 914 } 915 916 /* 917 * Make process 'parent' the new parent of process 'child'. 918 * Must be called with an exclusive hold of proctree lock. 919 */ 920 void 921 proc_reparent(struct proc *child, struct proc *parent) 922 { 923 924 sx_assert(&proctree_lock, SX_XLOCKED); 925 PROC_LOCK_ASSERT(child, MA_OWNED); 926 if (child->p_pptr == parent) 927 return; 928 929 PROC_LOCK(child->p_pptr); 930 sigqueue_take(child->p_ksi); 931 PROC_UNLOCK(child->p_pptr); 932 LIST_REMOVE(child, p_sibling); 933 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 934 child->p_pptr = parent; 935 } 936