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/mac.h> 69 #include <sys/shm.h> 70 #include <sys/sem.h> 71 #ifdef KTRACE 72 #include <sys/ktrace.h> 73 #endif 74 75 #include <vm/vm.h> 76 #include <vm/vm_extern.h> 77 #include <vm/vm_param.h> 78 #include <vm/pmap.h> 79 #include <vm/vm_map.h> 80 #include <vm/vm_page.h> 81 #include <vm/uma.h> 82 83 /* Required to be non-static for SysVR4 emulator */ 84 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 85 86 /* Hook for NFS teardown procedure. */ 87 void (*nlminfo_release_p)(struct proc *p); 88 89 /* 90 * exit -- 91 * Death of process. 92 * 93 * MPSAFE 94 */ 95 void 96 sys_exit(struct thread *td, struct sys_exit_args *uap) 97 { 98 99 exit1(td, W_EXITCODE(uap->rval, 0)); 100 /* NOTREACHED */ 101 } 102 103 /* 104 * Exit: deallocate address space and other resources, change proc state 105 * to zombie, and unlink proc from allproc and parent's lists. Save exit 106 * status and rusage for wait(). Check for child processes and orphan them. 107 */ 108 void 109 exit1(struct thread *td, int rv) 110 { 111 struct bintime new_switchtime; 112 struct proc *p, *nq, *q; 113 struct tty *tp; 114 struct vnode *ttyvp; 115 struct vmspace *vm; 116 struct vnode *vtmp; 117 #ifdef KTRACE 118 struct vnode *tracevp; 119 struct ucred *tracecred; 120 #endif 121 struct plimit *plim; 122 int locked, refcnt; 123 124 /* 125 * Drop Giant if caller has it. Eventually we should warn about 126 * being called with Giant held. 127 */ 128 while (mtx_owned(&Giant)) 129 mtx_unlock(&Giant); 130 131 p = td->td_proc; 132 if (p == initproc) { 133 printf("init died (signal %d, exit %d)\n", 134 WTERMSIG(rv), WEXITSTATUS(rv)); 135 panic("Going nowhere without my init!"); 136 } 137 138 /* 139 * MUST abort all other threads before proceeding past here. 140 */ 141 PROC_LOCK(p); 142 if (p->p_flag & P_HADTHREADS) { 143 retry: 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 goto retry; 169 170 /* 171 * All other activity in this process is now stopped. 172 * Threading support has been turned off. 173 */ 174 } 175 176 p->p_flag |= P_WEXIT; 177 178 PROC_LOCK(p->p_pptr); 179 sigqueue_take(p->p_ksi); 180 PROC_UNLOCK(p->p_pptr); 181 182 PROC_UNLOCK(p); 183 184 /* Are we a task leader? */ 185 if (p == p->p_leader) { 186 mtx_lock(&ppeers_lock); 187 q = p->p_peers; 188 while (q != NULL) { 189 PROC_LOCK(q); 190 psignal(q, SIGKILL); 191 PROC_UNLOCK(q); 192 q = q->p_peers; 193 } 194 while (p->p_peers != NULL) 195 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 196 mtx_unlock(&ppeers_lock); 197 } 198 199 PROC_LOCK(p); 200 _STOPEVENT(p, S_EXIT, rv); 201 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ 202 PROC_UNLOCK(p); 203 204 /* 205 * Check if any loadable modules need anything done at process exit. 206 * E.g. SYSV IPC stuff 207 * XXX what if one of these generates an error? 208 */ 209 EVENTHANDLER_INVOKE(process_exit, p); 210 211 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 212 M_ZOMBIE, M_WAITOK); 213 /* 214 * If parent is waiting for us to exit or exec, 215 * P_PPWAIT is set; we will wakeup the parent below. 216 */ 217 PROC_LOCK(p); 218 stopprofclock(p); 219 p->p_flag &= ~(P_TRACED | P_PPWAIT); 220 221 /* 222 * Stop the real interval timer. If the handler is currently 223 * executing, prevent it from rearming itself and let it finish. 224 */ 225 if (timevalisset(&p->p_realtimer.it_value) && 226 callout_stop(&p->p_itcallout) == 0) { 227 timevalclear(&p->p_realtimer.it_interval); 228 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 229 KASSERT(!timevalisset(&p->p_realtimer.it_value), 230 ("realtime timer is still armed")); 231 } 232 sigqueue_flush(&p->p_sigqueue); 233 sigqueue_flush(&td->td_sigqueue); 234 PROC_UNLOCK(p); 235 236 /* 237 * Reset any sigio structures pointing to us as a result of 238 * F_SETOWN with our pid. 239 */ 240 mtx_lock(&Giant); /* XXX: not sure if needed */ 241 funsetownlst(&p->p_sigiolst); 242 mtx_unlock(&Giant); 243 244 /* 245 * If this process has an nlminfo data area (for lockd), release it 246 */ 247 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 248 (*nlminfo_release_p)(p); 249 250 /* 251 * Close open files and release open-file table. 252 * This may block! 253 */ 254 fdfree(td); 255 256 /* 257 * If this thread tickled GEOM, we need to wait for the giggling to 258 * stop before we return to userland 259 */ 260 if (td->td_pflags & TDP_GEOM) 261 g_waitidle(); 262 263 /* 264 * Remove ourself from our leader's peer list and wake our leader. 265 */ 266 mtx_lock(&ppeers_lock); 267 if (p->p_leader->p_peers) { 268 q = p->p_leader; 269 while (q->p_peers != p) 270 q = q->p_peers; 271 q->p_peers = p->p_peers; 272 wakeup(p->p_leader); 273 } 274 mtx_unlock(&ppeers_lock); 275 276 /* The next two chunks should probably be moved to vmspace_exit. */ 277 vm = p->p_vmspace; 278 /* 279 * Release user portion of address space. 280 * This releases references to vnodes, 281 * which could cause I/O if the file has been unlinked. 282 * Need to do this early enough that we can still sleep. 283 * Can't free the entire vmspace as the kernel stack 284 * may be mapped within that space also. 285 * 286 * Processes sharing the same vmspace may exit in one order, and 287 * get cleaned up by vmspace_exit() in a different order. The 288 * last exiting process to reach this point releases as much of 289 * the environment as it can, and the last process cleaned up 290 * by vmspace_exit() (which decrements exitingcnt) cleans up the 291 * remainder. 292 */ 293 atomic_add_int(&vm->vm_exitingcnt, 1); 294 do 295 refcnt = vm->vm_refcnt; 296 while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); 297 if (refcnt == 1) { 298 shmexit(vm); 299 pmap_remove_pages(vmspace_pmap(vm), vm_map_min(&vm->vm_map), 300 vm_map_max(&vm->vm_map)); 301 (void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map), 302 vm_map_max(&vm->vm_map)); 303 } 304 305 sx_xlock(&proctree_lock); 306 if (SESS_LEADER(p)) { 307 struct session *sp; 308 309 sp = p->p_session; 310 if (sp->s_ttyvp) { 311 locked = VFS_LOCK_GIANT(sp->s_ttyvp->v_mount); 312 /* 313 * Controlling process. 314 * Signal foreground pgrp, 315 * drain controlling terminal 316 * and revoke access to controlling terminal. 317 */ 318 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 319 tp = sp->s_ttyp; 320 if (sp->s_ttyp->t_pgrp) { 321 PGRP_LOCK(sp->s_ttyp->t_pgrp); 322 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 323 PGRP_UNLOCK(sp->s_ttyp->t_pgrp); 324 } 325 /* XXX tp should be locked. */ 326 sx_xunlock(&proctree_lock); 327 (void) ttywait(tp); 328 sx_xlock(&proctree_lock); 329 /* 330 * The tty could have been revoked 331 * if we blocked. 332 */ 333 if (sp->s_ttyvp) { 334 ttyvp = sp->s_ttyvp; 335 SESS_LOCK(p->p_session); 336 sp->s_ttyvp = NULL; 337 SESS_UNLOCK(p->p_session); 338 sx_xunlock(&proctree_lock); 339 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td); 340 VOP_REVOKE(ttyvp, REVOKEALL); 341 vput(ttyvp); 342 sx_xlock(&proctree_lock); 343 } 344 } 345 if (sp->s_ttyvp) { 346 ttyvp = sp->s_ttyvp; 347 SESS_LOCK(p->p_session); 348 sp->s_ttyvp = NULL; 349 SESS_UNLOCK(p->p_session); 350 vrele(ttyvp); 351 } 352 /* 353 * s_ttyp is not zero'd; we use this to indicate 354 * that the session once had a controlling terminal. 355 * (for logging and informational purposes) 356 */ 357 VFS_UNLOCK_GIANT(locked); 358 } 359 SESS_LOCK(p->p_session); 360 sp->s_leader = NULL; 361 SESS_UNLOCK(p->p_session); 362 } 363 fixjobc(p, p->p_pgrp, 0); 364 sx_xunlock(&proctree_lock); 365 (void)acct_process(td); 366 #ifdef KTRACE 367 /* 368 * Drain any pending records on the thread and release the trace 369 * file. It might be better if drain-and-clear were atomic. 370 */ 371 ktrprocexit(td); 372 PROC_LOCK(p); 373 mtx_lock(&ktrace_mtx); 374 p->p_traceflag = 0; /* don't trace the vrele() */ 375 tracevp = p->p_tracevp; 376 p->p_tracevp = NULL; 377 tracecred = p->p_tracecred; 378 p->p_tracecred = NULL; 379 mtx_unlock(&ktrace_mtx); 380 PROC_UNLOCK(p); 381 if (tracevp != NULL) { 382 locked = VFS_LOCK_GIANT(tracevp->v_mount); 383 vrele(tracevp); 384 VFS_UNLOCK_GIANT(locked); 385 } 386 if (tracecred != NULL) 387 crfree(tracecred); 388 #endif 389 /* 390 * Release reference to text vnode 391 */ 392 if ((vtmp = p->p_textvp) != NULL) { 393 p->p_textvp = NULL; 394 locked = VFS_LOCK_GIANT(vtmp->v_mount); 395 vrele(vtmp); 396 VFS_UNLOCK_GIANT(locked); 397 } 398 399 /* 400 * Release our limits structure. 401 */ 402 PROC_LOCK(p); 403 plim = p->p_limit; 404 p->p_limit = NULL; 405 PROC_UNLOCK(p); 406 lim_free(plim); 407 408 /* 409 * Remove proc from allproc queue and pidhash chain. 410 * Place onto zombproc. Unlink from parent's child list. 411 */ 412 sx_xlock(&allproc_lock); 413 LIST_REMOVE(p, p_list); 414 LIST_INSERT_HEAD(&zombproc, p, p_list); 415 LIST_REMOVE(p, p_hash); 416 sx_xunlock(&allproc_lock); 417 418 sx_xlock(&proctree_lock); 419 q = LIST_FIRST(&p->p_children); 420 if (q != NULL) /* only need this if any child is S_ZOMB */ 421 wakeup(initproc); 422 for (; q != NULL; q = nq) { 423 nq = LIST_NEXT(q, p_sibling); 424 PROC_LOCK(q); 425 proc_reparent(q, initproc); 426 q->p_sigparent = SIGCHLD; 427 /* 428 * Traced processes are killed 429 * since their existence means someone is screwing up. 430 */ 431 if (q->p_flag & P_TRACED) { 432 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 433 psignal(q, SIGKILL); 434 } 435 PROC_UNLOCK(q); 436 } 437 438 /* 439 * Save exit status and finalize rusage info except for times, 440 * adding in child rusage info later when our time is locked. 441 */ 442 PROC_LOCK(p); 443 p->p_xstat = rv; 444 p->p_xthread = td; 445 p->p_stats->p_ru.ru_nvcsw++; 446 *p->p_ru = p->p_stats->p_ru; 447 448 /* 449 * Notify interested parties of our demise. 450 */ 451 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 452 453 /* 454 * Just delete all entries in the p_klist. At this point we won't 455 * report any more events, and there are nasty race conditions that 456 * can beat us if we don't. 457 */ 458 knlist_clear(&p->p_klist, 1); 459 460 /* 461 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 462 * flag set, or if the handler is set to SIG_IGN, notify process 463 * 1 instead (and hope it will handle this situation). 464 */ 465 PROC_LOCK(p->p_pptr); 466 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 467 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 468 struct proc *pp; 469 470 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 471 pp = p->p_pptr; 472 PROC_UNLOCK(pp); 473 proc_reparent(p, initproc); 474 p->p_sigparent = SIGCHLD; 475 PROC_LOCK(p->p_pptr); 476 /* 477 * If this was the last child of our parent, notify 478 * parent, so in case he was wait(2)ing, he will 479 * continue. 480 */ 481 if (LIST_EMPTY(&pp->p_children)) 482 wakeup(pp); 483 } else 484 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 485 486 if (p->p_pptr == initproc) 487 psignal(p->p_pptr, SIGCHLD); 488 else if (p->p_sigparent != 0) { 489 if (p->p_sigparent == SIGCHLD) 490 childproc_exited(p); 491 else /* LINUX thread */ 492 psignal(p->p_pptr, p->p_sigparent); 493 } 494 PROC_UNLOCK(p->p_pptr); 495 496 /* 497 * If this is a kthread, then wakeup anyone waiting for it to exit. 498 */ 499 if (p->p_flag & P_KTHREAD) 500 wakeup(p); 501 PROC_UNLOCK(p); 502 503 /* 504 * Finally, call machine-dependent code to release the remaining 505 * resources including address space. 506 * The address space is released by "vmspace_exitfree(p)" in 507 * vm_waitproc(). 508 */ 509 cpu_exit(td); 510 511 WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object, 512 "process (pid %d) exiting", p->p_pid); 513 514 PROC_LOCK(p); 515 PROC_LOCK(p->p_pptr); 516 sx_xunlock(&proctree_lock); 517 518 /* 519 * We have to wait until after acquiring all locks before 520 * changing p_state. We need to avoid all possible context 521 * switches (including ones from blocking on a mutex) while 522 * marked as a zombie. We also have to set the zombie state 523 * before we release the parent process' proc lock to avoid 524 * a lost wakeup. So, we first call wakeup, then we grab the 525 * sched lock, update the state, and release the parent process' 526 * proc lock. 527 */ 528 wakeup(p->p_pptr); 529 mtx_lock_spin(&sched_lock); 530 p->p_state = PRS_ZOMBIE; 531 PROC_UNLOCK(p->p_pptr); 532 533 ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 534 535 /* Do the same timestamp bookkeeping that mi_switch() would do. */ 536 binuptime(&new_switchtime); 537 bintime_add(&p->p_rux.rux_runtime, &new_switchtime); 538 bintime_sub(&p->p_rux.rux_runtime, PCPU_PTR(switchtime)); 539 PCPU_SET(switchtime, new_switchtime); 540 PCPU_SET(switchticks, ticks); 541 cnt.v_swtch++; 542 543 sched_exit(p->p_pptr, td); 544 545 /* 546 * Hopefully no one will try to deliver a signal to the process this 547 * late in the game. 548 */ 549 knlist_destroy(&p->p_klist); 550 551 /* 552 * Make sure the scheduler takes this thread out of its tables etc. 553 * This will also release this thread's reference to the ucred. 554 * Other thread parts to release include pcb bits and such. 555 */ 556 thread_exit(); 557 } 558 559 560 #ifndef _SYS_SYSPROTO_H_ 561 struct abort2_args { 562 char *why; 563 int nargs; 564 void **args; 565 }; 566 #endif 567 568 /* 569 * MPSAFE. 570 */ 571 int 572 abort2(struct thread *td, struct abort2_args *uap) 573 { 574 struct proc *p = td->td_proc; 575 struct sbuf *sb; 576 void *uargs[16]; 577 int error, i, sig; 578 579 error = 0; /* satisfy compiler */ 580 581 /* 582 * Do it right now so we can log either proper call of abort2(), or 583 * note, that invalid argument was passed. 512 is big enough to 584 * handle 16 arguments' descriptions with additional comments. 585 */ 586 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 587 sbuf_clear(sb); 588 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 589 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 590 /* 591 * Since we can't return from abort2(), send SIGKILL in cases, where 592 * abort2() was called improperly 593 */ 594 sig = SIGKILL; 595 /* Prevent from DoSes from user-space. */ 596 if (uap->nargs < 0 || uap->nargs > 16) 597 goto out; 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 * Limit size of 'reason' string to 128. Will fit even when 605 * maximal number of arguments was chosen to be logged. 606 */ 607 if (uap->why != NULL) { 608 error = sbuf_copyin(sb, uap->why, 128); 609 if (error < 0) 610 goto out; 611 } else { 612 sbuf_printf(sb, "(null)"); 613 } 614 if (uap->nargs) { 615 sbuf_printf(sb, "("); 616 for (i = 0;i < uap->nargs; i++) 617 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 618 sbuf_printf(sb, ")"); 619 } 620 /* 621 * Final stage: arguments were proper, string has been 622 * successfully copied from userspace, and copying pointers 623 * from user-space succeed. 624 */ 625 sig = SIGABRT; 626 out: 627 if (sig == SIGKILL) { 628 sbuf_trim(sb); 629 sbuf_printf(sb, " (Reason text inaccessible)"); 630 } 631 sbuf_cat(sb, "\n"); 632 sbuf_finish(sb); 633 log(LOG_INFO, "%s", sbuf_data(sb)); 634 sbuf_delete(sb); 635 exit1(td, W_EXITCODE(0, sig)); 636 return (0); 637 } 638 639 640 #ifdef COMPAT_43 641 /* 642 * The dirty work is handled by kern_wait(). 643 * 644 * MPSAFE. 645 */ 646 int 647 owait(struct thread *td, struct owait_args *uap __unused) 648 { 649 int error, status; 650 651 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 652 if (error == 0) 653 td->td_retval[1] = status; 654 return (error); 655 } 656 #endif /* COMPAT_43 */ 657 658 /* 659 * The dirty work is handled by kern_wait(). 660 * 661 * MPSAFE. 662 */ 663 int 664 wait4(struct thread *td, struct wait_args *uap) 665 { 666 struct rusage ru, *rup; 667 int error, status; 668 669 if (uap->rusage != NULL) 670 rup = &ru; 671 else 672 rup = NULL; 673 error = kern_wait(td, uap->pid, &status, uap->options, rup); 674 if (uap->status != NULL && error == 0) 675 error = copyout(&status, uap->status, sizeof(status)); 676 if (uap->rusage != NULL && error == 0) 677 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 678 return (error); 679 } 680 681 int 682 kern_wait(struct thread *td, pid_t pid, int *status, int options, 683 struct rusage *rusage) 684 { 685 struct proc *p, *q, *t; 686 int error, nfound; 687 688 q = td->td_proc; 689 if (pid == 0) { 690 PROC_LOCK(q); 691 pid = -q->p_pgid; 692 PROC_UNLOCK(q); 693 } 694 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 695 return (EINVAL); 696 loop: 697 if (q->p_flag & P_STATCHILD) { 698 PROC_LOCK(q); 699 q->p_flag &= ~P_STATCHILD; 700 PROC_UNLOCK(q); 701 } 702 nfound = 0; 703 sx_xlock(&proctree_lock); 704 LIST_FOREACH(p, &q->p_children, p_sibling) { 705 PROC_LOCK(p); 706 if (pid != WAIT_ANY && 707 p->p_pid != pid && p->p_pgid != -pid) { 708 PROC_UNLOCK(p); 709 continue; 710 } 711 if (p_canwait(td, p)) { 712 PROC_UNLOCK(p); 713 continue; 714 } 715 716 /* 717 * This special case handles a kthread spawned by linux_clone 718 * (see linux_misc.c). The linux_wait4 and linux_waitpid 719 * functions need to be able to distinguish between waiting 720 * on a process and waiting on a thread. It is a thread if 721 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 722 * signifies we want to wait for threads and not processes. 723 */ 724 if ((p->p_sigparent != SIGCHLD) ^ 725 ((options & WLINUXCLONE) != 0)) { 726 PROC_UNLOCK(p); 727 continue; 728 } 729 730 nfound++; 731 if (p->p_state == PRS_ZOMBIE) { 732 733 /* 734 * It is possible that the last thread of this 735 * process is still running on another CPU 736 * in thread_exit() after having dropped the process 737 * lock via PROC_UNLOCK() but before it has completed 738 * cpu_throw(). In that case, the other thread must 739 * still hold sched_lock, so simply by acquiring 740 * sched_lock once we will wait long enough for the 741 * thread to exit in that case. 742 */ 743 mtx_lock_spin(&sched_lock); 744 mtx_unlock_spin(&sched_lock); 745 746 td->td_retval[0] = p->p_pid; 747 if (status) 748 *status = p->p_xstat; /* convert to int */ 749 if (rusage) { 750 *rusage = *p->p_ru; 751 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 752 } 753 754 PROC_LOCK(q); 755 sigqueue_take(p->p_ksi); 756 PROC_UNLOCK(q); 757 758 /* 759 * If we got the child via a ptrace 'attach', 760 * we need to give it back to the old parent. 761 */ 762 PROC_UNLOCK(p); 763 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 764 PROC_LOCK(p); 765 p->p_oppid = 0; 766 proc_reparent(p, t); 767 PROC_UNLOCK(p); 768 tdsignal(t, NULL, SIGCHLD, p->p_ksi); 769 wakeup(t); 770 PROC_UNLOCK(t); 771 sx_xunlock(&proctree_lock); 772 return (0); 773 } 774 775 /* 776 * Remove other references to this process to ensure 777 * we have an exclusive reference. 778 */ 779 sx_xlock(&allproc_lock); 780 LIST_REMOVE(p, p_list); /* off zombproc */ 781 sx_xunlock(&allproc_lock); 782 LIST_REMOVE(p, p_sibling); 783 leavepgrp(p); 784 sx_xunlock(&proctree_lock); 785 786 /* 787 * As a side effect of this lock, we know that 788 * all other writes to this proc are visible now, so 789 * no more locking is needed for p. 790 */ 791 PROC_LOCK(p); 792 p->p_xstat = 0; /* XXX: why? */ 793 PROC_UNLOCK(p); 794 PROC_LOCK(q); 795 ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru, 796 &p->p_rux); 797 PROC_UNLOCK(q); 798 FREE(p->p_ru, M_ZOMBIE); 799 p->p_ru = NULL; 800 801 /* 802 * Decrement the count of procs running with this uid. 803 */ 804 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 805 806 /* 807 * Free credentials, arguments, and sigacts. 808 */ 809 crfree(p->p_ucred); 810 p->p_ucred = NULL; 811 pargs_drop(p->p_args); 812 p->p_args = NULL; 813 sigacts_free(p->p_sigacts); 814 p->p_sigacts = NULL; 815 816 /* 817 * Do any thread-system specific cleanups. 818 */ 819 thread_wait(p); 820 821 /* 822 * Give vm and machine-dependent layer a chance 823 * to free anything that cpu_exit couldn't 824 * release while still running in process context. 825 */ 826 vm_waitproc(p); 827 #ifdef MAC 828 mac_destroy_proc(p); 829 #endif 830 KASSERT(FIRST_THREAD_IN_PROC(p), 831 ("kern_wait: no residual thread!")); 832 uma_zfree(proc_zone, p); 833 sx_xlock(&allproc_lock); 834 nprocs--; 835 sx_xunlock(&allproc_lock); 836 return (0); 837 } 838 mtx_lock_spin(&sched_lock); 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 mtx_unlock_spin(&sched_lock); 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 PROC_UNLOCK(p); 850 851 PROC_LOCK(q); 852 sigqueue_take(p->p_ksi); 853 PROC_UNLOCK(q); 854 855 return (0); 856 } 857 mtx_unlock_spin(&sched_lock); 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 PROC_UNLOCK(p); 863 864 PROC_LOCK(q); 865 sigqueue_take(p->p_ksi); 866 PROC_UNLOCK(q); 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 { 903 904 sx_assert(&proctree_lock, SX_XLOCKED); 905 PROC_LOCK_ASSERT(child, MA_OWNED); 906 if (child->p_pptr == parent) 907 return; 908 909 LIST_REMOVE(child, p_sibling); 910 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 911 child->p_pptr = parent; 912 } 913