Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c
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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: releng/9.2/sys/kern/kern_exit.c 247349 2013-02-26 21:04:58Z jhb $"); 39 40 #include "opt_compat.h" 41 #include "opt_kdtrace.h" 42 #include "opt_ktrace.h" 43 #include "opt_procdesc.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/sysproto.h> 48 #include <sys/capability.h> 49 #include <sys/eventhandler.h> 50 #include <sys/kernel.h> 51 #include <sys/malloc.h> 52 #include <sys/lock.h> 53 #include <sys/mutex.h> 54 #include <sys/proc.h> 55 #include <sys/procdesc.h> 56 #include <sys/pioctl.h> 57 #include <sys/jail.h> 58 #include <sys/tty.h> 59 #include <sys/wait.h> 60 #include <sys/vmmeter.h> 61 #include <sys/vnode.h> 62 #include <sys/racct.h> 63 #include <sys/resourcevar.h> 64 #include <sys/sbuf.h> 65 #include <sys/signalvar.h> 66 #include <sys/sched.h> 67 #include <sys/sx.h> 68 #include <sys/syscallsubr.h> 69 #include <sys/syslog.h> 70 #include <sys/ptrace.h> 71 #include <sys/acct.h> /* for acct_process() function prototype */ 72 #include <sys/filedesc.h> 73 #include <sys/sdt.h> 74 #include <sys/shm.h> 75 #include <sys/sem.h> 76 #ifdef KTRACE 77 #include <sys/ktrace.h> 78 #endif 79 80 #include <security/audit/audit.h> 81 #include <security/mac/mac_framework.h> 82 83 #include <vm/vm.h> 84 #include <vm/vm_extern.h> 85 #include <vm/vm_param.h> 86 #include <vm/pmap.h> 87 #include <vm/vm_map.h> 88 #include <vm/vm_page.h> 89 #include <vm/uma.h> 90 91 #ifdef KDTRACE_HOOKS 92 #include <sys/dtrace_bsd.h> 93 dtrace_execexit_func_t dtrace_fasttrap_exit; 94 #endif 95 96 SDT_PROVIDER_DECLARE(proc); 97 SDT_PROBE_DEFINE(proc, kernel, , exit, exit); 98 SDT_PROBE_ARGTYPE(proc, kernel, , exit, 0, "int"); 99 100 /* Hook for NFS teardown procedure. */ 101 void (*nlminfo_release_p)(struct proc *p); 102 103 static void 104 clear_orphan(struct proc *p) 105 { 106 107 PROC_LOCK_ASSERT(p, MA_OWNED); 108 109 if (p->p_flag & P_ORPHAN) { 110 LIST_REMOVE(p, p_orphan); 111 p->p_flag &= ~P_ORPHAN; 112 } 113 } 114 115 /* 116 * exit -- death of process. 117 */ 118 void 119 sys_sys_exit(struct thread *td, struct sys_exit_args *uap) 120 { 121 122 exit1(td, W_EXITCODE(uap->rval, 0)); 123 /* NOTREACHED */ 124 } 125 126 /* 127 * Exit: deallocate address space and other resources, change proc state to 128 * zombie, and unlink proc from allproc and parent's lists. Save exit status 129 * and rusage for wait(). Check for child processes and orphan them. 130 */ 131 void 132 exit1(struct thread *td, int rv) 133 { 134 struct proc *p, *nq, *q; 135 struct vnode *vtmp; 136 struct vnode *ttyvp = NULL; 137 struct plimit *plim; 138 int locked; 139 140 mtx_assert(&Giant, MA_NOTOWNED); 141 142 p = td->td_proc; 143 /* 144 * XXX in case we're rebooting we just let init die in order to 145 * work around an unsolved stack overflow seen very late during 146 * shutdown on sparc64 when the gmirror worker process exists. 147 */ 148 if (p == initproc && rebooting == 0) { 149 printf("init died (signal %d, exit %d)\n", 150 WTERMSIG(rv), WEXITSTATUS(rv)); 151 panic("Going nowhere without my init!"); 152 } 153 154 /* 155 * MUST abort all other threads before proceeding past here. 156 */ 157 PROC_LOCK(p); 158 while (p->p_flag & P_HADTHREADS) { 159 /* 160 * First check if some other thread got here before us.. 161 * if so, act apropriatly, (exit or suspend); 162 */ 163 thread_suspend_check(0); 164 165 /* 166 * Kill off the other threads. This requires 167 * some co-operation from other parts of the kernel 168 * so it may not be instantaneous. With this state set 169 * any thread entering the kernel from userspace will 170 * thread_exit() in trap(). Any thread attempting to 171 * sleep will return immediately with EINTR or EWOULDBLOCK 172 * which will hopefully force them to back out to userland 173 * freeing resources as they go. Any thread attempting 174 * to return to userland will thread_exit() from userret(). 175 * thread_exit() will unsuspend us when the last of the 176 * other threads exits. 177 * If there is already a thread singler after resumption, 178 * calling thread_single will fail; in that case, we just 179 * re-check all suspension request, the thread should 180 * either be suspended there or exit. 181 */ 182 if (! thread_single(SINGLE_EXIT)) 183 break; 184 185 /* 186 * All other activity in this process is now stopped. 187 * Threading support has been turned off. 188 */ 189 } 190 KASSERT(p->p_numthreads == 1, 191 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 192 racct_sub(p, RACCT_NTHR, 1); 193 /* 194 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 195 * on our vmspace, so we should block below until they have 196 * released their reference to us. Note that if they have 197 * requested S_EXIT stops we will block here until they ack 198 * via PIOCCONT. 199 */ 200 _STOPEVENT(p, S_EXIT, rv); 201 202 /* 203 * Ignore any pending request to stop due to a stop signal. 204 * Once P_WEXIT is set, future requests will be ignored as 205 * well. 206 */ 207 p->p_flag &= ~P_STOPPED_SIG; 208 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped")); 209 210 /* 211 * Note that we are exiting and do another wakeup of anyone in 212 * PIOCWAIT in case they aren't listening for S_EXIT stops or 213 * decided to wait again after we told them we are exiting. 214 */ 215 p->p_flag |= P_WEXIT; 216 wakeup(&p->p_stype); 217 218 /* 219 * Wait for any processes that have a hold on our vmspace to 220 * release their reference. 221 */ 222 while (p->p_lock > 0) 223 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 224 225 p->p_xstat = rv; /* Let event handler change exit status */ 226 PROC_UNLOCK(p); 227 /* Drain the limit callout while we don't have the proc locked */ 228 callout_drain(&p->p_limco); 229 230 #ifdef AUDIT 231 /* 232 * The Sun BSM exit token contains two components: an exit status as 233 * passed to exit(), and a return value to indicate what sort of exit 234 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 235 * what the return value is. 236 */ 237 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0); 238 AUDIT_SYSCALL_EXIT(0, td); 239 #endif 240 241 /* Are we a task leader? */ 242 if (p == p->p_leader) { 243 mtx_lock(&ppeers_lock); 244 q = p->p_peers; 245 while (q != NULL) { 246 PROC_LOCK(q); 247 kern_psignal(q, SIGKILL); 248 PROC_UNLOCK(q); 249 q = q->p_peers; 250 } 251 while (p->p_peers != NULL) 252 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 253 mtx_unlock(&ppeers_lock); 254 } 255 256 /* 257 * Check if any loadable modules need anything done at process exit. 258 * E.g. SYSV IPC stuff 259 * XXX what if one of these generates an error? 260 */ 261 EVENTHANDLER_INVOKE(process_exit, p); 262 263 /* 264 * If parent is waiting for us to exit or exec, 265 * P_PPWAIT is set; we will wakeup the parent below. 266 */ 267 PROC_LOCK(p); 268 rv = p->p_xstat; /* Event handler could change exit status */ 269 stopprofclock(p); 270 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE); 271 272 /* 273 * Stop the real interval timer. If the handler is currently 274 * executing, prevent it from rearming itself and let it finish. 275 */ 276 if (timevalisset(&p->p_realtimer.it_value) && 277 callout_stop(&p->p_itcallout) == 0) { 278 timevalclear(&p->p_realtimer.it_interval); 279 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 280 KASSERT(!timevalisset(&p->p_realtimer.it_value), 281 ("realtime timer is still armed")); 282 } 283 PROC_UNLOCK(p); 284 285 /* 286 * Reset any sigio structures pointing to us as a result of 287 * F_SETOWN with our pid. 288 */ 289 funsetownlst(&p->p_sigiolst); 290 291 /* 292 * If this process has an nlminfo data area (for lockd), release it 293 */ 294 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 295 (*nlminfo_release_p)(p); 296 297 /* 298 * Close open files and release open-file table. 299 * This may block! 300 */ 301 fdfree(td); 302 303 /* 304 * If this thread tickled GEOM, we need to wait for the giggling to 305 * stop before we return to userland 306 */ 307 if (td->td_pflags & TDP_GEOM) 308 g_waitidle(); 309 310 /* 311 * Remove ourself from our leader's peer list and wake our leader. 312 */ 313 mtx_lock(&ppeers_lock); 314 if (p->p_leader->p_peers) { 315 q = p->p_leader; 316 while (q->p_peers != p) 317 q = q->p_peers; 318 q->p_peers = p->p_peers; 319 wakeup(p->p_leader); 320 } 321 mtx_unlock(&ppeers_lock); 322 323 vmspace_exit(td); 324 325 sx_xlock(&proctree_lock); 326 if (SESS_LEADER(p)) { 327 struct session *sp = p->p_session; 328 struct tty *tp; 329 330 /* 331 * s_ttyp is not zero'd; we use this to indicate that 332 * the session once had a controlling terminal. (for 333 * logging and informational purposes) 334 */ 335 SESS_LOCK(sp); 336 ttyvp = sp->s_ttyvp; 337 tp = sp->s_ttyp; 338 sp->s_ttyvp = NULL; 339 sp->s_ttydp = NULL; 340 sp->s_leader = NULL; 341 SESS_UNLOCK(sp); 342 343 /* 344 * Signal foreground pgrp and revoke access to 345 * controlling terminal if it has not been revoked 346 * already. 347 * 348 * Because the TTY may have been revoked in the mean 349 * time and could already have a new session associated 350 * with it, make sure we don't send a SIGHUP to a 351 * foreground process group that does not belong to this 352 * session. 353 */ 354 355 if (tp != NULL) { 356 tty_lock(tp); 357 if (tp->t_session == sp) 358 tty_signal_pgrp(tp, SIGHUP); 359 tty_unlock(tp); 360 } 361 362 if (ttyvp != NULL) { 363 sx_xunlock(&proctree_lock); 364 if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) { 365 VOP_REVOKE(ttyvp, REVOKEALL); 366 VOP_UNLOCK(ttyvp, 0); 367 } 368 sx_xlock(&proctree_lock); 369 } 370 } 371 fixjobc(p, p->p_pgrp, 0); 372 sx_xunlock(&proctree_lock); 373 (void)acct_process(td); 374 375 /* Release the TTY now we've unlocked everything. */ 376 if (ttyvp != NULL) 377 vrele(ttyvp); 378 #ifdef KTRACE 379 ktrprocexit(td); 380 #endif 381 /* 382 * Release reference to text vnode 383 */ 384 if ((vtmp = p->p_textvp) != NULL) { 385 p->p_textvp = NULL; 386 locked = VFS_LOCK_GIANT(vtmp->v_mount); 387 vrele(vtmp); 388 VFS_UNLOCK_GIANT(locked); 389 } 390 391 /* 392 * Release our limits structure. 393 */ 394 PROC_LOCK(p); 395 plim = p->p_limit; 396 p->p_limit = NULL; 397 PROC_UNLOCK(p); 398 lim_free(plim); 399 400 tidhash_remove(td); 401 402 /* 403 * Remove proc from allproc queue and pidhash chain. 404 * Place onto zombproc. Unlink from parent's child list. 405 */ 406 sx_xlock(&allproc_lock); 407 LIST_REMOVE(p, p_list); 408 LIST_INSERT_HEAD(&zombproc, p, p_list); 409 LIST_REMOVE(p, p_hash); 410 sx_xunlock(&allproc_lock); 411 412 /* 413 * Call machine-dependent code to release any 414 * machine-dependent resources other than the address space. 415 * The address space is released by "vmspace_exitfree(p)" in 416 * vm_waitproc(). 417 */ 418 cpu_exit(td); 419 420 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 421 422 /* 423 * Reparent all of our children to init. 424 */ 425 sx_xlock(&proctree_lock); 426 q = LIST_FIRST(&p->p_children); 427 if (q != NULL) /* only need this if any child is S_ZOMB */ 428 wakeup(initproc); 429 for (; q != NULL; q = nq) { 430 nq = LIST_NEXT(q, p_sibling); 431 PROC_LOCK(q); 432 proc_reparent(q, initproc); 433 q->p_sigparent = SIGCHLD; 434 /* 435 * Traced processes are killed 436 * since their existence means someone is screwing up. 437 */ 438 if (q->p_flag & P_TRACED) { 439 struct thread *temp; 440 441 /* 442 * Since q was found on our children list, the 443 * proc_reparent() call moved q to the orphan 444 * list due to present P_TRACED flag. Clear 445 * orphan link for q now while q is locked. 446 */ 447 clear_orphan(q); 448 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 449 FOREACH_THREAD_IN_PROC(q, temp) 450 temp->td_dbgflags &= ~TDB_SUSPEND; 451 kern_psignal(q, SIGKILL); 452 } 453 PROC_UNLOCK(q); 454 } 455 456 /* 457 * Also get rid of our orphans. 458 */ 459 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) { 460 PROC_LOCK(q); 461 clear_orphan(q); 462 PROC_UNLOCK(q); 463 } 464 465 /* Save exit status. */ 466 PROC_LOCK(p); 467 p->p_xthread = td; 468 469 /* Tell the prison that we are gone. */ 470 prison_proc_free(p->p_ucred->cr_prison); 471 472 #ifdef KDTRACE_HOOKS 473 /* 474 * Tell the DTrace fasttrap provider about the exit if it 475 * has declared an interest. 476 */ 477 if (dtrace_fasttrap_exit) 478 dtrace_fasttrap_exit(p); 479 #endif 480 481 /* 482 * Notify interested parties of our demise. 483 */ 484 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 485 486 #ifdef KDTRACE_HOOKS 487 int reason = CLD_EXITED; 488 if (WCOREDUMP(rv)) 489 reason = CLD_DUMPED; 490 else if (WIFSIGNALED(rv)) 491 reason = CLD_KILLED; 492 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 493 #endif 494 495 /* 496 * Just delete all entries in the p_klist. At this point we won't 497 * report any more events, and there are nasty race conditions that 498 * can beat us if we don't. 499 */ 500 knlist_clear(&p->p_klist, 1); 501 502 /* 503 * If this is a process with a descriptor, we may not need to deliver 504 * a signal to the parent. proctree_lock is held over 505 * procdesc_exit() to serialize concurrent calls to close() and 506 * exit(). 507 */ 508 #ifdef PROCDESC 509 if (p->p_procdesc == NULL || procdesc_exit(p)) { 510 #endif 511 /* 512 * Notify parent that we're gone. If parent has the 513 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN, 514 * notify process 1 instead (and hope it will handle this 515 * situation). 516 */ 517 PROC_LOCK(p->p_pptr); 518 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 519 if (p->p_pptr->p_sigacts->ps_flag & 520 (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 521 struct proc *pp; 522 523 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 524 pp = p->p_pptr; 525 PROC_UNLOCK(pp); 526 proc_reparent(p, initproc); 527 p->p_sigparent = SIGCHLD; 528 PROC_LOCK(p->p_pptr); 529 530 /* 531 * Notify parent, so in case he was wait(2)ing or 532 * executing waitpid(2) with our pid, he will 533 * continue. 534 */ 535 wakeup(pp); 536 } else 537 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 538 539 if (p->p_pptr == initproc) 540 kern_psignal(p->p_pptr, SIGCHLD); 541 else if (p->p_sigparent != 0) { 542 if (p->p_sigparent == SIGCHLD) 543 childproc_exited(p); 544 else /* LINUX thread */ 545 kern_psignal(p->p_pptr, p->p_sigparent); 546 } 547 #ifdef PROCDESC 548 } else 549 PROC_LOCK(p->p_pptr); 550 #endif 551 sx_xunlock(&proctree_lock); 552 553 /* 554 * The state PRS_ZOMBIE prevents other proesses from sending 555 * signal to the process, to avoid memory leak, we free memory 556 * for signal queue at the time when the state is set. 557 */ 558 sigqueue_flush(&p->p_sigqueue); 559 sigqueue_flush(&td->td_sigqueue); 560 561 /* 562 * We have to wait until after acquiring all locks before 563 * changing p_state. We need to avoid all possible context 564 * switches (including ones from blocking on a mutex) while 565 * marked as a zombie. We also have to set the zombie state 566 * before we release the parent process' proc lock to avoid 567 * a lost wakeup. So, we first call wakeup, then we grab the 568 * sched lock, update the state, and release the parent process' 569 * proc lock. 570 */ 571 wakeup(p->p_pptr); 572 cv_broadcast(&p->p_pwait); 573 sched_exit(p->p_pptr, td); 574 PROC_SLOCK(p); 575 p->p_state = PRS_ZOMBIE; 576 PROC_UNLOCK(p->p_pptr); 577 578 /* 579 * Hopefully no one will try to deliver a signal to the process this 580 * late in the game. 581 */ 582 knlist_destroy(&p->p_klist); 583 584 /* 585 * Save our children's rusage information in our exit rusage. 586 */ 587 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 588 589 /* 590 * Make sure the scheduler takes this thread out of its tables etc. 591 * This will also release this thread's reference to the ucred. 592 * Other thread parts to release include pcb bits and such. 593 */ 594 thread_exit(); 595 } 596 597 598 #ifndef _SYS_SYSPROTO_H_ 599 struct abort2_args { 600 char *why; 601 int nargs; 602 void **args; 603 }; 604 #endif 605 606 int 607 sys_abort2(struct thread *td, struct abort2_args *uap) 608 { 609 struct proc *p = td->td_proc; 610 struct sbuf *sb; 611 void *uargs[16]; 612 int error, i, sig; 613 614 /* 615 * Do it right now so we can log either proper call of abort2(), or 616 * note, that invalid argument was passed. 512 is big enough to 617 * handle 16 arguments' descriptions with additional comments. 618 */ 619 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 620 sbuf_clear(sb); 621 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 622 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 623 /* 624 * Since we can't return from abort2(), send SIGKILL in cases, where 625 * abort2() was called improperly 626 */ 627 sig = SIGKILL; 628 /* Prevent from DoSes from user-space. */ 629 if (uap->nargs < 0 || uap->nargs > 16) 630 goto out; 631 if (uap->nargs > 0) { 632 if (uap->args == NULL) 633 goto out; 634 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 635 if (error != 0) 636 goto out; 637 } 638 /* 639 * Limit size of 'reason' string to 128. Will fit even when 640 * maximal number of arguments was chosen to be logged. 641 */ 642 if (uap->why != NULL) { 643 error = sbuf_copyin(sb, uap->why, 128); 644 if (error < 0) 645 goto out; 646 } else { 647 sbuf_printf(sb, "(null)"); 648 } 649 if (uap->nargs > 0) { 650 sbuf_printf(sb, "("); 651 for (i = 0;i < uap->nargs; i++) 652 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 653 sbuf_printf(sb, ")"); 654 } 655 /* 656 * Final stage: arguments were proper, string has been 657 * successfully copied from userspace, and copying pointers 658 * from user-space succeed. 659 */ 660 sig = SIGABRT; 661 out: 662 if (sig == SIGKILL) { 663 sbuf_trim(sb); 664 sbuf_printf(sb, " (Reason text inaccessible)"); 665 } 666 sbuf_cat(sb, "\n"); 667 sbuf_finish(sb); 668 log(LOG_INFO, "%s", sbuf_data(sb)); 669 sbuf_delete(sb); 670 exit1(td, W_EXITCODE(0, sig)); 671 return (0); 672 } 673 674 675 #ifdef COMPAT_43 676 /* 677 * The dirty work is handled by kern_wait(). 678 */ 679 int 680 owait(struct thread *td, struct owait_args *uap __unused) 681 { 682 int error, status; 683 684 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 685 if (error == 0) 686 td->td_retval[1] = status; 687 return (error); 688 } 689 #endif /* COMPAT_43 */ 690 691 /* 692 * The dirty work is handled by kern_wait(). 693 */ 694 int 695 sys_wait4(struct thread *td, struct wait4_args *uap) 696 { 697 struct rusage ru, *rup; 698 int error, status; 699 700 if (uap->rusage != NULL) 701 rup = &ru; 702 else 703 rup = NULL; 704 error = kern_wait(td, uap->pid, &status, uap->options, rup); 705 if (uap->status != NULL && error == 0) 706 error = copyout(&status, uap->status, sizeof(status)); 707 if (uap->rusage != NULL && error == 0) 708 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 709 return (error); 710 } 711 712 int 713 sys_wait6(struct thread *td, struct wait6_args *uap) 714 { 715 struct __wrusage wru, *wrup; 716 siginfo_t si, *sip; 717 idtype_t idtype; 718 id_t id; 719 int error, status; 720 721 idtype = uap->idtype; 722 id = uap->id; 723 724 if (uap->wrusage != NULL) 725 wrup = &wru; 726 else 727 wrup = NULL; 728 729 if (uap->info != NULL) { 730 sip = &si; 731 bzero(sip, sizeof(*sip)); 732 } else 733 sip = NULL; 734 735 /* 736 * We expect all callers of wait6() to know about WEXITED and 737 * WTRAPPED. 738 */ 739 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip); 740 741 if (uap->status != NULL && error == 0) 742 error = copyout(&status, uap->status, sizeof(status)); 743 if (uap->wrusage != NULL && error == 0) 744 error = copyout(&wru, uap->wrusage, sizeof(wru)); 745 if (uap->info != NULL && error == 0) 746 error = copyout(&si, uap->info, sizeof(si)); 747 return (error); 748 } 749 750 /* 751 * Reap the remains of a zombie process and optionally return status and 752 * rusage. Asserts and will release both the proctree_lock and the process 753 * lock as part of its work. 754 */ 755 void 756 proc_reap(struct thread *td, struct proc *p, int *status, int options) 757 { 758 struct proc *q, *t; 759 760 sx_assert(&proctree_lock, SA_XLOCKED); 761 PROC_LOCK_ASSERT(p, MA_OWNED); 762 PROC_SLOCK_ASSERT(p, MA_OWNED); 763 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 764 765 q = td->td_proc; 766 767 PROC_SUNLOCK(p); 768 td->td_retval[0] = p->p_pid; 769 if (status) 770 *status = p->p_xstat; /* convert to int */ 771 if (options & WNOWAIT) { 772 /* 773 * Only poll, returning the status. Caller does not wish to 774 * release the proc struct just yet. 775 */ 776 PROC_UNLOCK(p); 777 sx_xunlock(&proctree_lock); 778 return; 779 } 780 781 PROC_LOCK(q); 782 sigqueue_take(p->p_ksi); 783 PROC_UNLOCK(q); 784 PROC_UNLOCK(p); 785 786 /* 787 * If we got the child via a ptrace 'attach', we need to give it back 788 * to the old parent. 789 */ 790 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 791 PROC_LOCK(p); 792 proc_reparent(p, t); 793 p->p_oppid = 0; 794 PROC_UNLOCK(p); 795 pksignal(t, SIGCHLD, p->p_ksi); 796 wakeup(t); 797 cv_broadcast(&p->p_pwait); 798 PROC_UNLOCK(t); 799 sx_xunlock(&proctree_lock); 800 return; 801 } 802 803 /* 804 * Remove other references to this process to ensure we have an 805 * exclusive reference. 806 */ 807 sx_xlock(&allproc_lock); 808 LIST_REMOVE(p, p_list); /* off zombproc */ 809 sx_xunlock(&allproc_lock); 810 LIST_REMOVE(p, p_sibling); 811 PROC_LOCK(p); 812 clear_orphan(p); 813 PROC_UNLOCK(p); 814 leavepgrp(p); 815 #ifdef PROCDESC 816 if (p->p_procdesc != NULL) 817 procdesc_reap(p); 818 #endif 819 sx_xunlock(&proctree_lock); 820 821 /* 822 * As a side effect of this lock, we know that all other writes to 823 * this proc are visible now, so no more locking is needed for p. 824 */ 825 PROC_LOCK(p); 826 p->p_xstat = 0; /* XXX: why? */ 827 PROC_UNLOCK(p); 828 PROC_LOCK(q); 829 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 830 PROC_UNLOCK(q); 831 832 /* 833 * Decrement the count of procs running with this uid. 834 */ 835 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 836 837 /* 838 * Destroy resource accounting information associated with the process. 839 */ 840 #ifdef RACCT 841 PROC_LOCK(p); 842 racct_sub(p, RACCT_NPROC, 1); 843 PROC_UNLOCK(p); 844 #endif 845 racct_proc_exit(p); 846 847 /* 848 * Free credentials, arguments, and sigacts. 849 */ 850 crfree(p->p_ucred); 851 p->p_ucred = NULL; 852 pargs_drop(p->p_args); 853 p->p_args = NULL; 854 sigacts_free(p->p_sigacts); 855 p->p_sigacts = NULL; 856 857 /* 858 * Do any thread-system specific cleanups. 859 */ 860 thread_wait(p); 861 862 /* 863 * Give vm and machine-dependent layer a chance to free anything that 864 * cpu_exit couldn't release while still running in process context. 865 */ 866 vm_waitproc(p); 867 #ifdef MAC 868 mac_proc_destroy(p); 869 #endif 870 KASSERT(FIRST_THREAD_IN_PROC(p), 871 ("proc_reap: no residual thread!")); 872 uma_zfree(proc_zone, p); 873 sx_xlock(&allproc_lock); 874 nprocs--; 875 sx_xunlock(&allproc_lock); 876 } 877 878 static int 879 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id, 880 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo) 881 { 882 struct proc *q; 883 struct rusage *rup; 884 885 sx_assert(&proctree_lock, SA_XLOCKED); 886 887 q = td->td_proc; 888 PROC_LOCK(p); 889 890 switch (idtype) { 891 case P_ALL: 892 break; 893 case P_PID: 894 if (p->p_pid != (pid_t)id) { 895 PROC_UNLOCK(p); 896 return (0); 897 } 898 break; 899 case P_PGID: 900 if (p->p_pgid != (pid_t)id) { 901 PROC_UNLOCK(p); 902 return (0); 903 } 904 break; 905 case P_SID: 906 if (p->p_session->s_sid != (pid_t)id) { 907 PROC_UNLOCK(p); 908 return (0); 909 } 910 break; 911 case P_UID: 912 if (p->p_ucred->cr_uid != (uid_t)id) { 913 PROC_UNLOCK(p); 914 return (0); 915 } 916 break; 917 case P_GID: 918 if (p->p_ucred->cr_gid != (gid_t)id) { 919 PROC_UNLOCK(p); 920 return (0); 921 } 922 break; 923 case P_JAILID: 924 if (p->p_ucred->cr_prison == NULL || 925 (p->p_ucred->cr_prison->pr_id != (int)id)) { 926 PROC_UNLOCK(p); 927 return (0); 928 } 929 break; 930 /* 931 * It seems that the thread structures get zeroed out 932 * at process exit. This makes it impossible to 933 * support P_SETID, P_CID or P_CPUID. 934 */ 935 default: 936 PROC_UNLOCK(p); 937 return (0); 938 } 939 940 if (p_canwait(td, p)) { 941 PROC_UNLOCK(p); 942 return (0); 943 } 944 945 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) { 946 PROC_UNLOCK(p); 947 return (0); 948 } 949 950 /* 951 * This special case handles a kthread spawned by linux_clone 952 * (see linux_misc.c). The linux_wait4 and linux_waitpid 953 * functions need to be able to distinguish between waiting 954 * on a process and waiting on a thread. It is a thread if 955 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 956 * signifies we want to wait for threads and not processes. 957 */ 958 if ((p->p_sigparent != SIGCHLD) ^ 959 ((options & WLINUXCLONE) != 0)) { 960 PROC_UNLOCK(p); 961 return (0); 962 } 963 964 PROC_SLOCK(p); 965 966 if (siginfo != NULL) { 967 bzero(siginfo, sizeof(*siginfo)); 968 siginfo->si_errno = 0; 969 970 /* 971 * SUSv4 requires that the si_signo value is always 972 * SIGCHLD. Obey it despite the rfork(2) interface 973 * allows to request other signal for child exit 974 * notification. 975 */ 976 siginfo->si_signo = SIGCHLD; 977 978 /* 979 * This is still a rough estimate. We will fix the 980 * cases TRAPPED, STOPPED, and CONTINUED later. 981 */ 982 if (WCOREDUMP(p->p_xstat)) 983 siginfo->si_code = CLD_DUMPED; 984 else if (WIFSIGNALED(p->p_xstat)) 985 siginfo->si_code = CLD_KILLED; 986 else 987 siginfo->si_code = CLD_EXITED; 988 989 siginfo->si_pid = p->p_pid; 990 siginfo->si_uid = p->p_ucred->cr_uid; 991 siginfo->si_status = p->p_xstat; 992 993 /* 994 * The si_addr field would be useful additional 995 * detail, but apparently the PC value may be lost 996 * when we reach this point. bzero() above sets 997 * siginfo->si_addr to NULL. 998 */ 999 } 1000 1001 /* 1002 * There should be no reason to limit resources usage info to 1003 * exited processes only. A snapshot about any resources used 1004 * by a stopped process may be exactly what is needed. 1005 */ 1006 if (wrusage != NULL) { 1007 rup = &wrusage->wru_self; 1008 *rup = p->p_ru; 1009 calcru(p, &rup->ru_utime, &rup->ru_stime); 1010 1011 rup = &wrusage->wru_children; 1012 *rup = p->p_stats->p_cru; 1013 calccru(p, &rup->ru_utime, &rup->ru_stime); 1014 } 1015 1016 if (p->p_state == PRS_ZOMBIE) { 1017 proc_reap(td, p, status, options); 1018 return (-1); 1019 } 1020 PROC_SUNLOCK(p); 1021 PROC_UNLOCK(p); 1022 return (1); 1023 } 1024 1025 int 1026 kern_wait(struct thread *td, pid_t pid, int *status, int options, 1027 struct rusage *rusage) 1028 { 1029 struct __wrusage wru, *wrup; 1030 idtype_t idtype; 1031 id_t id; 1032 int ret; 1033 1034 /* 1035 * Translate the special pid values into the (idtype, pid) 1036 * pair for kern_wait6. The WAIT_MYPGRP case is handled by 1037 * kern_wait6() on its own. 1038 */ 1039 if (pid == WAIT_ANY) { 1040 idtype = P_ALL; 1041 id = 0; 1042 } else if (pid < 0) { 1043 idtype = P_PGID; 1044 id = (id_t)-pid; 1045 } else { 1046 idtype = P_PID; 1047 id = (id_t)pid; 1048 } 1049 1050 if (rusage != NULL) 1051 wrup = &wru; 1052 else 1053 wrup = NULL; 1054 1055 /* 1056 * For backward compatibility we implicitly add flags WEXITED 1057 * and WTRAPPED here. 1058 */ 1059 options |= WEXITED | WTRAPPED; 1060 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL); 1061 if (rusage != NULL) 1062 *rusage = wru.wru_self; 1063 return (ret); 1064 } 1065 1066 int 1067 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status, 1068 int options, struct __wrusage *wrusage, siginfo_t *siginfo) 1069 { 1070 struct proc *p, *q; 1071 int error, nfound, ret; 1072 1073 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */ 1074 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */ 1075 AUDIT_ARG_VALUE(options); 1076 1077 q = td->td_proc; 1078 1079 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { 1080 PROC_LOCK(q); 1081 id = (id_t)q->p_pgid; 1082 PROC_UNLOCK(q); 1083 idtype = P_PGID; 1084 } 1085 1086 /* If we don't know the option, just return. */ 1087 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT | 1088 WEXITED | WTRAPPED | WLINUXCLONE)) != 0) 1089 return (EINVAL); 1090 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) { 1091 /* 1092 * We will be unable to find any matching processes, 1093 * because there are no known events to look for. 1094 * Prefer to return error instead of blocking 1095 * indefinitely. 1096 */ 1097 return (EINVAL); 1098 } 1099 1100 loop: 1101 if (q->p_flag & P_STATCHILD) { 1102 PROC_LOCK(q); 1103 q->p_flag &= ~P_STATCHILD; 1104 PROC_UNLOCK(q); 1105 } 1106 nfound = 0; 1107 sx_xlock(&proctree_lock); 1108 LIST_FOREACH(p, &q->p_children, p_sibling) { 1109 ret = proc_to_reap(td, p, idtype, id, status, options, 1110 wrusage, siginfo); 1111 if (ret == 0) 1112 continue; 1113 else if (ret == 1) 1114 nfound++; 1115 else 1116 return (0); 1117 1118 PROC_LOCK(p); 1119 PROC_SLOCK(p); 1120 1121 if ((options & WTRAPPED) != 0 && 1122 (p->p_flag & P_TRACED) != 0 && 1123 (p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) != 0 && 1124 (p->p_suspcount == p->p_numthreads) && 1125 ((p->p_flag & P_WAITED) == 0)) { 1126 PROC_SUNLOCK(p); 1127 if ((options & WNOWAIT) == 0) 1128 p->p_flag |= P_WAITED; 1129 sx_xunlock(&proctree_lock); 1130 td->td_retval[0] = p->p_pid; 1131 1132 if (status != NULL) 1133 *status = W_STOPCODE(p->p_xstat); 1134 if (siginfo != NULL) { 1135 siginfo->si_status = p->p_xstat; 1136 siginfo->si_code = CLD_TRAPPED; 1137 } 1138 if ((options & WNOWAIT) == 0) { 1139 PROC_LOCK(q); 1140 sigqueue_take(p->p_ksi); 1141 PROC_UNLOCK(q); 1142 } 1143 1144 PROC_UNLOCK(p); 1145 return (0); 1146 } 1147 if ((options & WUNTRACED) != 0 && 1148 (p->p_flag & P_STOPPED_SIG) != 0 && 1149 (p->p_suspcount == p->p_numthreads) && 1150 ((p->p_flag & P_WAITED) == 0)) { 1151 PROC_SUNLOCK(p); 1152 if ((options & WNOWAIT) == 0) 1153 p->p_flag |= P_WAITED; 1154 sx_xunlock(&proctree_lock); 1155 td->td_retval[0] = p->p_pid; 1156 1157 if (status != NULL) 1158 *status = W_STOPCODE(p->p_xstat); 1159 if (siginfo != NULL) { 1160 siginfo->si_status = p->p_xstat; 1161 siginfo->si_code = CLD_STOPPED; 1162 } 1163 if ((options & WNOWAIT) == 0) { 1164 PROC_LOCK(q); 1165 sigqueue_take(p->p_ksi); 1166 PROC_UNLOCK(q); 1167 } 1168 1169 PROC_UNLOCK(p); 1170 return (0); 1171 } 1172 PROC_SUNLOCK(p); 1173 if ((options & WCONTINUED) != 0 && 1174 (p->p_flag & P_CONTINUED) != 0) { 1175 sx_xunlock(&proctree_lock); 1176 td->td_retval[0] = p->p_pid; 1177 if ((options & WNOWAIT) == 0) { 1178 p->p_flag &= ~P_CONTINUED; 1179 PROC_LOCK(q); 1180 sigqueue_take(p->p_ksi); 1181 PROC_UNLOCK(q); 1182 } 1183 PROC_UNLOCK(p); 1184 1185 if (status != NULL) 1186 *status = SIGCONT; 1187 if (siginfo != NULL) { 1188 siginfo->si_status = SIGCONT; 1189 siginfo->si_code = CLD_CONTINUED; 1190 } 1191 return (0); 1192 } 1193 PROC_UNLOCK(p); 1194 } 1195 1196 /* 1197 * Look in the orphans list too, to allow the parent to 1198 * collect it's child exit status even if child is being 1199 * debugged. 1200 * 1201 * Debugger detaches from the parent upon successful 1202 * switch-over from parent to child. At this point due to 1203 * re-parenting the parent loses the child to debugger and a 1204 * wait4(2) call would report that it has no children to wait 1205 * for. By maintaining a list of orphans we allow the parent 1206 * to successfully wait until the child becomes a zombie. 1207 */ 1208 LIST_FOREACH(p, &q->p_orphans, p_orphan) { 1209 ret = proc_to_reap(td, p, idtype, id, status, options, 1210 wrusage, siginfo); 1211 if (ret == 0) 1212 continue; 1213 else if (ret == 1) 1214 nfound++; 1215 else 1216 return (0); 1217 } 1218 if (nfound == 0) { 1219 sx_xunlock(&proctree_lock); 1220 return (ECHILD); 1221 } 1222 if (options & WNOHANG) { 1223 sx_xunlock(&proctree_lock); 1224 td->td_retval[0] = 0; 1225 return (0); 1226 } 1227 PROC_LOCK(q); 1228 sx_xunlock(&proctree_lock); 1229 if (q->p_flag & P_STATCHILD) { 1230 q->p_flag &= ~P_STATCHILD; 1231 error = 0; 1232 } else 1233 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 1234 PROC_UNLOCK(q); 1235 if (error) 1236 return (error); 1237 goto loop; 1238 } 1239 1240 /* 1241 * Make process 'parent' the new parent of process 'child'. 1242 * Must be called with an exclusive hold of proctree lock. 1243 */ 1244 void 1245 proc_reparent(struct proc *child, struct proc *parent) 1246 { 1247 1248 sx_assert(&proctree_lock, SX_XLOCKED); 1249 PROC_LOCK_ASSERT(child, MA_OWNED); 1250 if (child->p_pptr == parent) 1251 return; 1252 1253 PROC_LOCK(child->p_pptr); 1254 sigqueue_take(child->p_ksi); 1255 PROC_UNLOCK(child->p_pptr); 1256 LIST_REMOVE(child, p_sibling); 1257 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1258 1259 clear_orphan(child); 1260 if (child->p_flag & P_TRACED) { 1261 LIST_INSERT_HEAD(&child->p_pptr->p_orphans, child, p_orphan); 1262 child->p_flag |= P_ORPHAN; 1263 } 1264 1265 child->p_pptr = parent; 1266 }
Cache object: ee5e37e1efb7af05779ceec848a6a32f
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