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 tty *tp; 123 struct vnode *ttyvp; 124 struct vnode *vtmp; 125 #ifdef KTRACE 126 struct vnode *tracevp; 127 struct ucred *tracecred; 128 #endif 129 struct plimit *plim; 130 int locked; 131 132 mtx_assert(&Giant, MA_NOTOWNED); 133 134 p = td->td_proc; 135 if (p == initproc) { 136 printf("init died (signal %d, exit %d)\n", 137 WTERMSIG(rv), WEXITSTATUS(rv)); 138 panic("Going nowhere without my init!"); 139 } 140 141 /* 142 * MUST abort all other threads before proceeding past here. 143 */ 144 PROC_LOCK(p); 145 while (p->p_flag & P_HADTHREADS) { 146 /* 147 * First check if some other thread got here before us.. 148 * if so, act apropriatly, (exit or suspend); 149 */ 150 thread_suspend_check(0); 151 152 /* 153 * Kill off the other threads. This requires 154 * some co-operation from other parts of the kernel 155 * so it may not be instantaneous. With this state set 156 * any thread entering the kernel from userspace will 157 * thread_exit() in trap(). Any thread attempting to 158 * sleep will return immediately with EINTR or EWOULDBLOCK 159 * which will hopefully force them to back out to userland 160 * freeing resources as they go. Any thread attempting 161 * to return to userland will thread_exit() from userret(). 162 * thread_exit() will unsuspend us when the last of the 163 * other threads exits. 164 * If there is already a thread singler after resumption, 165 * calling thread_single will fail; in that case, we just 166 * re-check all suspension request, the thread should 167 * either be suspended there or exit. 168 */ 169 if (! thread_single(SINGLE_EXIT)) 170 break; 171 172 /* 173 * All other activity in this process is now stopped. 174 * Threading support has been turned off. 175 */ 176 } 177 KASSERT(p->p_numthreads == 1, 178 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 179 /* 180 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 181 * on our vmspace, so we should block below until they have 182 * released their reference to us. Note that if they have 183 * requested S_EXIT stops we will block here until they ack 184 * via PIOCCONT. 185 */ 186 _STOPEVENT(p, S_EXIT, rv); 187 188 /* 189 * Note that we are exiting and do another wakeup of anyone in 190 * PIOCWAIT in case they aren't listening for S_EXIT stops or 191 * decided to wait again after we told them we are exiting. 192 */ 193 p->p_flag |= P_WEXIT; 194 wakeup(&p->p_stype); 195 196 /* 197 * Wait for any processes that have a hold on our vmspace to 198 * release their reference. 199 */ 200 while (p->p_lock > 0) 201 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 202 203 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 stopprofclock(p); 246 p->p_flag &= ~(P_TRACED | P_PPWAIT); 247 248 /* 249 * Stop the real interval timer. If the handler is currently 250 * executing, prevent it from rearming itself and let it finish. 251 */ 252 if (timevalisset(&p->p_realtimer.it_value) && 253 callout_stop(&p->p_itcallout) == 0) { 254 timevalclear(&p->p_realtimer.it_interval); 255 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 256 KASSERT(!timevalisset(&p->p_realtimer.it_value), 257 ("realtime timer is still armed")); 258 } 259 PROC_UNLOCK(p); 260 261 /* 262 * Reset any sigio structures pointing to us as a result of 263 * F_SETOWN with our pid. 264 */ 265 funsetownlst(&p->p_sigiolst); 266 267 /* 268 * If this process has an nlminfo data area (for lockd), release it 269 */ 270 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 271 (*nlminfo_release_p)(p); 272 273 /* 274 * Close open files and release open-file table. 275 * This may block! 276 */ 277 fdfree(td); 278 279 /* 280 * If this thread tickled GEOM, we need to wait for the giggling to 281 * stop before we return to userland 282 */ 283 if (td->td_pflags & TDP_GEOM) 284 g_waitidle(); 285 286 /* 287 * Remove ourself from our leader's peer list and wake our leader. 288 */ 289 mtx_lock(&ppeers_lock); 290 if (p->p_leader->p_peers) { 291 q = p->p_leader; 292 while (q->p_peers != p) 293 q = q->p_peers; 294 q->p_peers = p->p_peers; 295 wakeup(p->p_leader); 296 } 297 mtx_unlock(&ppeers_lock); 298 299 vmspace_exit(td); 300 301 mtx_lock(&Giant); /* XXX TTY */ 302 sx_xlock(&proctree_lock); 303 if (SESS_LEADER(p)) { 304 struct session *sp; 305 306 sp = p->p_session; 307 if (sp->s_ttyvp) { 308 /* 309 * Controlling process. 310 * Signal foreground pgrp, 311 * drain controlling terminal 312 * and revoke access to controlling terminal. 313 */ 314 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 315 tp = sp->s_ttyp; 316 if (sp->s_ttyp->t_pgrp) { 317 PGRP_LOCK(sp->s_ttyp->t_pgrp); 318 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 319 PGRP_UNLOCK(sp->s_ttyp->t_pgrp); 320 } 321 /* XXX tp should be locked. */ 322 sx_xunlock(&proctree_lock); 323 (void) ttywait(tp); 324 sx_xlock(&proctree_lock); 325 /* 326 * The tty could have been revoked 327 * if we blocked. 328 */ 329 if (sp->s_ttyvp) { 330 ttyvp = sp->s_ttyvp; 331 SESS_LOCK(p->p_session); 332 sp->s_ttyvp = NULL; 333 SESS_UNLOCK(p->p_session); 334 sx_xunlock(&proctree_lock); 335 VOP_LOCK(ttyvp, LK_EXCLUSIVE); 336 VOP_REVOKE(ttyvp, REVOKEALL); 337 vput(ttyvp); 338 sx_xlock(&proctree_lock); 339 } 340 } 341 if (sp->s_ttyvp) { 342 ttyvp = sp->s_ttyvp; 343 SESS_LOCK(p->p_session); 344 sp->s_ttyvp = NULL; 345 SESS_UNLOCK(p->p_session); 346 vrele(ttyvp); 347 } 348 /* 349 * s_ttyp is not zero'd; we use this to indicate 350 * that the session once had a controlling terminal. 351 * (for logging and informational purposes) 352 */ 353 } 354 SESS_LOCK(p->p_session); 355 sp->s_leader = NULL; 356 SESS_UNLOCK(p->p_session); 357 } 358 fixjobc(p, p->p_pgrp, 0); 359 sx_xunlock(&proctree_lock); 360 (void)acct_process(td); 361 mtx_unlock(&Giant); 362 #ifdef KTRACE 363 /* 364 * Disable tracing, then drain any pending records and release 365 * the trace file. 366 */ 367 if (p->p_traceflag != 0) { 368 PROC_LOCK(p); 369 mtx_lock(&ktrace_mtx); 370 p->p_traceflag = 0; 371 mtx_unlock(&ktrace_mtx); 372 PROC_UNLOCK(p); 373 ktrprocexit(td); 374 PROC_LOCK(p); 375 mtx_lock(&ktrace_mtx); 376 tracevp = p->p_tracevp; 377 p->p_tracevp = NULL; 378 tracecred = p->p_tracecred; 379 p->p_tracecred = NULL; 380 mtx_unlock(&ktrace_mtx); 381 PROC_UNLOCK(p); 382 if (tracevp != NULL) { 383 locked = VFS_LOCK_GIANT(tracevp->v_mount); 384 vrele(tracevp); 385 VFS_UNLOCK_GIANT(locked); 386 } 387 if (tracecred != NULL) 388 crfree(tracecred); 389 } 390 #endif 391 /* 392 * Release reference to text vnode 393 */ 394 if ((vtmp = p->p_textvp) != NULL) { 395 p->p_textvp = NULL; 396 locked = VFS_LOCK_GIANT(vtmp->v_mount); 397 vrele(vtmp); 398 VFS_UNLOCK_GIANT(locked); 399 } 400 401 /* 402 * Release our limits structure. 403 */ 404 PROC_LOCK(p); 405 plim = p->p_limit; 406 p->p_limit = NULL; 407 PROC_UNLOCK(p); 408 lim_free(plim); 409 410 /* 411 * Remove proc from allproc queue and pidhash chain. 412 * Place onto zombproc. Unlink from parent's child list. 413 */ 414 sx_xlock(&allproc_lock); 415 LIST_REMOVE(p, p_list); 416 LIST_INSERT_HEAD(&zombproc, p, p_list); 417 LIST_REMOVE(p, p_hash); 418 sx_xunlock(&allproc_lock); 419 420 /* 421 * Call machine-dependent code to release any 422 * machine-dependent resources other than the address space. 423 * The address space is released by "vmspace_exitfree(p)" in 424 * vm_waitproc(). 425 */ 426 cpu_exit(td); 427 428 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 429 430 /* 431 * Reparent all of our children to init. 432 */ 433 sx_xlock(&proctree_lock); 434 q = LIST_FIRST(&p->p_children); 435 if (q != NULL) /* only need this if any child is S_ZOMB */ 436 wakeup(initproc); 437 for (; q != NULL; q = nq) { 438 nq = LIST_NEXT(q, p_sibling); 439 PROC_LOCK(q); 440 proc_reparent(q, initproc); 441 q->p_sigparent = SIGCHLD; 442 /* 443 * Traced processes are killed 444 * since their existence means someone is screwing up. 445 */ 446 if (q->p_flag & P_TRACED) { 447 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 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 #ifdef KDTRACE_HOOKS 459 /* 460 * Tell the DTrace fasttrap provider about the exit if it 461 * has declared an interest. 462 */ 463 if (dtrace_fasttrap_exit) 464 dtrace_fasttrap_exit(p); 465 #endif 466 467 /* 468 * Notify interested parties of our demise. 469 */ 470 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 471 472 #ifdef KDTRACE_HOOKS 473 int reason = CLD_EXITED; 474 if (WCOREDUMP(rv)) 475 reason = CLD_DUMPED; 476 else if (WIFSIGNALED(rv)) 477 reason = CLD_KILLED; 478 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 479 #endif 480 481 /* 482 * Just delete all entries in the p_klist. At this point we won't 483 * report any more events, and there are nasty race conditions that 484 * can beat us if we don't. 485 */ 486 knlist_clear(&p->p_klist, 1); 487 488 /* 489 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 490 * flag set, or if the handler is set to SIG_IGN, notify process 491 * 1 instead (and hope it will handle this situation). 492 */ 493 PROC_LOCK(p->p_pptr); 494 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 495 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 496 struct proc *pp; 497 498 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 499 pp = p->p_pptr; 500 PROC_UNLOCK(pp); 501 proc_reparent(p, initproc); 502 p->p_sigparent = SIGCHLD; 503 PROC_LOCK(p->p_pptr); 504 /* 505 * If this was the last child of our parent, notify 506 * parent, so in case he was wait(2)ing, he will 507 * continue. 508 */ 509 if (LIST_EMPTY(&pp->p_children)) 510 wakeup(pp); 511 } else 512 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 513 514 if (p->p_pptr == initproc) 515 psignal(p->p_pptr, SIGCHLD); 516 else if (p->p_sigparent != 0) { 517 if (p->p_sigparent == SIGCHLD) 518 childproc_exited(p); 519 else /* LINUX thread */ 520 psignal(p->p_pptr, p->p_sigparent); 521 } 522 sx_xunlock(&proctree_lock); 523 524 /* 525 * The state PRS_ZOMBIE prevents other proesses from sending 526 * signal to the process, to avoid memory leak, we free memory 527 * for signal queue at the time when the state is set. 528 */ 529 sigqueue_flush(&p->p_sigqueue); 530 sigqueue_flush(&td->td_sigqueue); 531 532 /* 533 * We have to wait until after acquiring all locks before 534 * changing p_state. We need to avoid all possible context 535 * switches (including ones from blocking on a mutex) while 536 * marked as a zombie. We also have to set the zombie state 537 * before we release the parent process' proc lock to avoid 538 * a lost wakeup. So, we first call wakeup, then we grab the 539 * sched lock, update the state, and release the parent process' 540 * proc lock. 541 */ 542 wakeup(p->p_pptr); 543 sched_exit(p->p_pptr, td); 544 PROC_SLOCK(p); 545 p->p_state = PRS_ZOMBIE; 546 PROC_UNLOCK(p->p_pptr); 547 548 /* 549 * Hopefully no one will try to deliver a signal to the process this 550 * late in the game. 551 */ 552 knlist_destroy(&p->p_klist); 553 554 /* 555 * Save our children's rusage information in our exit rusage. 556 */ 557 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 558 559 /* 560 * Make sure the scheduler takes this thread out of its tables etc. 561 * This will also release this thread's reference to the ucred. 562 * Other thread parts to release include pcb bits and such. 563 */ 564 thread_exit(); 565 } 566 567 568 #ifndef _SYS_SYSPROTO_H_ 569 struct abort2_args { 570 char *why; 571 int nargs; 572 void **args; 573 }; 574 #endif 575 576 int 577 abort2(struct thread *td, struct abort2_args *uap) 578 { 579 struct proc *p = td->td_proc; 580 struct sbuf *sb; 581 void *uargs[16]; 582 int error, i, sig; 583 584 error = 0; /* satisfy compiler */ 585 586 /* 587 * Do it right now so we can log either proper call of abort2(), or 588 * note, that invalid argument was passed. 512 is big enough to 589 * handle 16 arguments' descriptions with additional comments. 590 */ 591 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 592 sbuf_clear(sb); 593 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 594 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 595 /* 596 * Since we can't return from abort2(), send SIGKILL in cases, where 597 * abort2() was called improperly 598 */ 599 sig = SIGKILL; 600 /* Prevent from DoSes from user-space. */ 601 if (uap->nargs < 0 || uap->nargs > 16) 602 goto out; 603 if (uap->nargs > 0) { 604 if (uap->args == NULL) 605 goto out; 606 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 607 if (error != 0) 608 goto out; 609 } 610 /* 611 * Limit size of 'reason' string to 128. Will fit even when 612 * maximal number of arguments was chosen to be logged. 613 */ 614 if (uap->why != NULL) { 615 error = sbuf_copyin(sb, uap->why, 128); 616 if (error < 0) 617 goto out; 618 } else { 619 sbuf_printf(sb, "(null)"); 620 } 621 if (uap->nargs > 0) { 622 sbuf_printf(sb, "("); 623 for (i = 0;i < uap->nargs; i++) 624 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 625 sbuf_printf(sb, ")"); 626 } 627 /* 628 * Final stage: arguments were proper, string has been 629 * successfully copied from userspace, and copying pointers 630 * from user-space succeed. 631 */ 632 sig = SIGABRT; 633 out: 634 if (sig == SIGKILL) { 635 sbuf_trim(sb); 636 sbuf_printf(sb, " (Reason text inaccessible)"); 637 } 638 sbuf_cat(sb, "\n"); 639 sbuf_finish(sb); 640 log(LOG_INFO, "%s", sbuf_data(sb)); 641 sbuf_delete(sb); 642 exit1(td, W_EXITCODE(0, sig)); 643 return (0); 644 } 645 646 647 #ifdef COMPAT_43 648 /* 649 * The dirty work is handled by kern_wait(). 650 */ 651 int 652 owait(struct thread *td, struct owait_args *uap __unused) 653 { 654 int error, status; 655 656 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 657 if (error == 0) 658 td->td_retval[1] = status; 659 return (error); 660 } 661 #endif /* COMPAT_43 */ 662 663 /* 664 * The dirty work is handled by kern_wait(). 665 */ 666 int 667 wait4(struct thread *td, struct wait_args *uap) 668 { 669 struct rusage ru, *rup; 670 int error, status; 671 672 if (uap->rusage != NULL) 673 rup = &ru; 674 else 675 rup = NULL; 676 error = kern_wait(td, uap->pid, &status, uap->options, rup); 677 if (uap->status != NULL && error == 0) 678 error = copyout(&status, uap->status, sizeof(status)); 679 if (uap->rusage != NULL && error == 0) 680 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 681 return (error); 682 } 683 684 int 685 kern_wait(struct thread *td, pid_t pid, int *status, int options, 686 struct rusage *rusage) 687 { 688 struct proc *p, *q, *t; 689 int error, nfound; 690 691 AUDIT_ARG(pid, pid); 692 693 q = td->td_proc; 694 if (pid == 0) { 695 PROC_LOCK(q); 696 pid = -q->p_pgid; 697 PROC_UNLOCK(q); 698 } 699 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) 700 return (EINVAL); 701 loop: 702 if (q->p_flag & P_STATCHILD) { 703 PROC_LOCK(q); 704 q->p_flag &= ~P_STATCHILD; 705 PROC_UNLOCK(q); 706 } 707 nfound = 0; 708 sx_xlock(&proctree_lock); 709 LIST_FOREACH(p, &q->p_children, p_sibling) { 710 PROC_LOCK(p); 711 if (pid != WAIT_ANY && 712 p->p_pid != pid && p->p_pgid != -pid) { 713 PROC_UNLOCK(p); 714 continue; 715 } 716 if (p_canwait(td, p)) { 717 PROC_UNLOCK(p); 718 continue; 719 } 720 721 /* 722 * This special case handles a kthread spawned by linux_clone 723 * (see linux_misc.c). The linux_wait4 and linux_waitpid 724 * functions need to be able to distinguish between waiting 725 * on a process and waiting on a thread. It is a thread if 726 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 727 * signifies we want to wait for threads and not processes. 728 */ 729 if ((p->p_sigparent != SIGCHLD) ^ 730 ((options & WLINUXCLONE) != 0)) { 731 PROC_UNLOCK(p); 732 continue; 733 } 734 735 nfound++; 736 PROC_SLOCK(p); 737 if (p->p_state == PRS_ZOMBIE) { 738 if (rusage) { 739 *rusage = p->p_ru; 740 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 741 } 742 PROC_SUNLOCK(p); 743 td->td_retval[0] = p->p_pid; 744 if (status) 745 *status = p->p_xstat; /* convert to int */ 746 PROC_LOCK(q); 747 sigqueue_take(p->p_ksi); 748 PROC_UNLOCK(q); 749 750 /* 751 * If we got the child via a ptrace 'attach', 752 * we need to give it back to the old parent. 753 */ 754 PROC_UNLOCK(p); 755 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 756 PROC_LOCK(p); 757 p->p_oppid = 0; 758 proc_reparent(p, t); 759 PROC_UNLOCK(p); 760 tdsignal(t, NULL, SIGCHLD, p->p_ksi); 761 wakeup(t); 762 PROC_UNLOCK(t); 763 sx_xunlock(&proctree_lock); 764 return (0); 765 } 766 767 /* 768 * Remove other references to this process to ensure 769 * we have an exclusive reference. 770 */ 771 sx_xlock(&allproc_lock); 772 LIST_REMOVE(p, p_list); /* off zombproc */ 773 sx_xunlock(&allproc_lock); 774 LIST_REMOVE(p, p_sibling); 775 leavepgrp(p); 776 sx_xunlock(&proctree_lock); 777 778 /* 779 * As a side effect of this lock, we know that 780 * all other writes to this proc are visible now, so 781 * no more locking is needed for p. 782 */ 783 PROC_LOCK(p); 784 p->p_xstat = 0; /* XXX: why? */ 785 PROC_UNLOCK(p); 786 PROC_LOCK(q); 787 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, 788 &p->p_rux); 789 PROC_UNLOCK(q); 790 791 /* 792 * Decrement the count of procs running with this uid. 793 */ 794 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 795 796 /* 797 * Free credentials, arguments, and sigacts. 798 */ 799 crfree(p->p_ucred); 800 p->p_ucred = NULL; 801 pargs_drop(p->p_args); 802 p->p_args = NULL; 803 sigacts_free(p->p_sigacts); 804 p->p_sigacts = NULL; 805 806 /* 807 * Do any thread-system specific cleanups. 808 */ 809 thread_wait(p); 810 811 /* 812 * Give vm and machine-dependent layer a chance 813 * to free anything that cpu_exit couldn't 814 * release while still running in process context. 815 */ 816 vm_waitproc(p); 817 #ifdef MAC 818 mac_proc_destroy(p); 819 #endif 820 KASSERT(FIRST_THREAD_IN_PROC(p), 821 ("kern_wait: no residual thread!")); 822 uma_zfree(proc_zone, p); 823 sx_xlock(&allproc_lock); 824 nprocs--; 825 sx_xunlock(&allproc_lock); 826 return (0); 827 } 828 if ((p->p_flag & P_STOPPED_SIG) && 829 (p->p_suspcount == p->p_numthreads) && 830 (p->p_flag & P_WAITED) == 0 && 831 (p->p_flag & P_TRACED || options & WUNTRACED)) { 832 PROC_SUNLOCK(p); 833 p->p_flag |= P_WAITED; 834 sx_xunlock(&proctree_lock); 835 td->td_retval[0] = p->p_pid; 836 if (status) 837 *status = W_STOPCODE(p->p_xstat); 838 839 PROC_LOCK(q); 840 sigqueue_take(p->p_ksi); 841 PROC_UNLOCK(q); 842 PROC_UNLOCK(p); 843 844 return (0); 845 } 846 PROC_SUNLOCK(p); 847 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 848 sx_xunlock(&proctree_lock); 849 td->td_retval[0] = p->p_pid; 850 p->p_flag &= ~P_CONTINUED; 851 852 PROC_LOCK(q); 853 sigqueue_take(p->p_ksi); 854 PROC_UNLOCK(q); 855 PROC_UNLOCK(p); 856 857 if (status) 858 *status = SIGCONT; 859 return (0); 860 } 861 PROC_UNLOCK(p); 862 } 863 if (nfound == 0) { 864 sx_xunlock(&proctree_lock); 865 return (ECHILD); 866 } 867 if (options & WNOHANG) { 868 sx_xunlock(&proctree_lock); 869 td->td_retval[0] = 0; 870 return (0); 871 } 872 PROC_LOCK(q); 873 sx_xunlock(&proctree_lock); 874 if (q->p_flag & P_STATCHILD) { 875 q->p_flag &= ~P_STATCHILD; 876 error = 0; 877 } else 878 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 879 PROC_UNLOCK(q); 880 if (error) 881 return (error); 882 goto loop; 883 } 884 885 /* 886 * Make process 'parent' the new parent of process 'child'. 887 * Must be called with an exclusive hold of proctree lock. 888 */ 889 void 890 proc_reparent(struct proc *child, struct proc *parent) 891 { 892 893 sx_assert(&proctree_lock, SX_XLOCKED); 894 PROC_LOCK_ASSERT(child, MA_OWNED); 895 if (child->p_pptr == parent) 896 return; 897 898 PROC_LOCK(child->p_pptr); 899 sigqueue_take(child->p_ksi); 900 PROC_UNLOCK(child->p_pptr); 901 LIST_REMOVE(child, p_sibling); 902 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 903 child->p_pptr = parent; 904 } 905