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/9.0/sys/kern/kern_exit.c 225641 2011-09-17 19:55:32Z trasz $"); 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 /* 104 * exit -- death of process. 105 */ 106 void 107 sys_sys_exit(struct thread *td, struct sys_exit_args *uap) 108 { 109 110 exit1(td, W_EXITCODE(uap->rval, 0)); 111 /* NOTREACHED */ 112 } 113 114 /* 115 * Exit: deallocate address space and other resources, change proc state to 116 * zombie, and unlink proc from allproc and parent's lists. Save exit status 117 * and rusage for wait(). Check for child processes and orphan them. 118 */ 119 void 120 exit1(struct thread *td, int rv) 121 { 122 struct proc *p, *nq, *q; 123 struct vnode *vtmp; 124 struct vnode *ttyvp = NULL; 125 struct plimit *plim; 126 int locked; 127 128 mtx_assert(&Giant, MA_NOTOWNED); 129 130 p = td->td_proc; 131 /* 132 * XXX in case we're rebooting we just let init die in order to 133 * work around an unsolved stack overflow seen very late during 134 * shutdown on sparc64 when the gmirror worker process exists. 135 */ 136 if (p == initproc && rebooting == 0) { 137 printf("init died (signal %d, exit %d)\n", 138 WTERMSIG(rv), WEXITSTATUS(rv)); 139 panic("Going nowhere without my init!"); 140 } 141 142 /* 143 * MUST abort all other threads before proceeding past here. 144 */ 145 PROC_LOCK(p); 146 while (p->p_flag & P_HADTHREADS) { 147 /* 148 * First check if some other thread got here before us.. 149 * if so, act apropriatly, (exit or suspend); 150 */ 151 thread_suspend_check(0); 152 153 /* 154 * Kill off the other threads. This requires 155 * some co-operation from other parts of the kernel 156 * so it may not be instantaneous. With this state set 157 * any thread entering the kernel from userspace will 158 * thread_exit() in trap(). Any thread attempting to 159 * sleep will return immediately with EINTR or EWOULDBLOCK 160 * which will hopefully force them to back out to userland 161 * freeing resources as they go. Any thread attempting 162 * to return to userland will thread_exit() from userret(). 163 * thread_exit() will unsuspend us when the last of the 164 * other threads exits. 165 * If there is already a thread singler after resumption, 166 * calling thread_single will fail; in that case, we just 167 * re-check all suspension request, the thread should 168 * either be suspended there or exit. 169 */ 170 if (! thread_single(SINGLE_EXIT)) 171 break; 172 173 /* 174 * All other activity in this process is now stopped. 175 * Threading support has been turned off. 176 */ 177 } 178 KASSERT(p->p_numthreads == 1, 179 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 180 racct_sub(p, RACCT_NTHR, 1); 181 /* 182 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 183 * on our vmspace, so we should block below until they have 184 * released their reference to us. Note that if they have 185 * requested S_EXIT stops we will block here until they ack 186 * via PIOCCONT. 187 */ 188 _STOPEVENT(p, S_EXIT, rv); 189 190 /* 191 * Note that we are exiting and do another wakeup of anyone in 192 * PIOCWAIT in case they aren't listening for S_EXIT stops or 193 * decided to wait again after we told them we are exiting. 194 */ 195 p->p_flag |= P_WEXIT; 196 wakeup(&p->p_stype); 197 198 /* 199 * Wait for any processes that have a hold on our vmspace to 200 * release their reference. 201 */ 202 while (p->p_lock > 0) 203 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 204 205 p->p_xstat = rv; /* Let event handler change exit status */ 206 PROC_UNLOCK(p); 207 /* Drain the limit callout while we don't have the proc locked */ 208 callout_drain(&p->p_limco); 209 210 #ifdef AUDIT 211 /* 212 * The Sun BSM exit token contains two components: an exit status as 213 * passed to exit(), and a return value to indicate what sort of exit 214 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 215 * what the return value is. 216 */ 217 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0); 218 AUDIT_SYSCALL_EXIT(0, td); 219 #endif 220 221 /* Are we a task leader? */ 222 if (p == p->p_leader) { 223 mtx_lock(&ppeers_lock); 224 q = p->p_peers; 225 while (q != NULL) { 226 PROC_LOCK(q); 227 kern_psignal(q, SIGKILL); 228 PROC_UNLOCK(q); 229 q = q->p_peers; 230 } 231 while (p->p_peers != NULL) 232 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 233 mtx_unlock(&ppeers_lock); 234 } 235 236 /* 237 * Check if any loadable modules need anything done at process exit. 238 * E.g. SYSV IPC stuff 239 * XXX what if one of these generates an error? 240 */ 241 EVENTHANDLER_INVOKE(process_exit, p); 242 243 /* 244 * If parent is waiting for us to exit or exec, 245 * P_PPWAIT is set; we will wakeup the parent below. 246 */ 247 PROC_LOCK(p); 248 rv = p->p_xstat; /* Event handler could change exit status */ 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 ktrprocexit(td); 360 #endif 361 /* 362 * Release reference to text vnode 363 */ 364 if ((vtmp = p->p_textvp) != NULL) { 365 p->p_textvp = NULL; 366 locked = VFS_LOCK_GIANT(vtmp->v_mount); 367 vrele(vtmp); 368 VFS_UNLOCK_GIANT(locked); 369 } 370 371 /* 372 * Release our limits structure. 373 */ 374 PROC_LOCK(p); 375 plim = p->p_limit; 376 p->p_limit = NULL; 377 PROC_UNLOCK(p); 378 lim_free(plim); 379 380 tidhash_remove(td); 381 382 /* 383 * Remove proc from allproc queue and pidhash chain. 384 * Place onto zombproc. Unlink from parent's child list. 385 */ 386 sx_xlock(&allproc_lock); 387 LIST_REMOVE(p, p_list); 388 LIST_INSERT_HEAD(&zombproc, p, p_list); 389 LIST_REMOVE(p, p_hash); 390 sx_xunlock(&allproc_lock); 391 392 /* 393 * Call machine-dependent code to release any 394 * machine-dependent resources other than the address space. 395 * The address space is released by "vmspace_exitfree(p)" in 396 * vm_waitproc(). 397 */ 398 cpu_exit(td); 399 400 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 401 402 /* 403 * Reparent all of our children to init. 404 */ 405 sx_xlock(&proctree_lock); 406 q = LIST_FIRST(&p->p_children); 407 if (q != NULL) /* only need this if any child is S_ZOMB */ 408 wakeup(initproc); 409 for (; q != NULL; q = nq) { 410 nq = LIST_NEXT(q, p_sibling); 411 PROC_LOCK(q); 412 proc_reparent(q, initproc); 413 q->p_sigparent = SIGCHLD; 414 /* 415 * Traced processes are killed 416 * since their existence means someone is screwing up. 417 */ 418 if (q->p_flag & P_TRACED) { 419 struct thread *temp; 420 421 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 422 FOREACH_THREAD_IN_PROC(q, temp) 423 temp->td_dbgflags &= ~TDB_SUSPEND; 424 kern_psignal(q, SIGKILL); 425 } 426 PROC_UNLOCK(q); 427 } 428 429 /* Save exit status. */ 430 PROC_LOCK(p); 431 p->p_xthread = td; 432 433 /* Tell the prison that we are gone. */ 434 prison_proc_free(p->p_ucred->cr_prison); 435 436 #ifdef KDTRACE_HOOKS 437 /* 438 * Tell the DTrace fasttrap provider about the exit if it 439 * has declared an interest. 440 */ 441 if (dtrace_fasttrap_exit) 442 dtrace_fasttrap_exit(p); 443 #endif 444 445 /* 446 * Notify interested parties of our demise. 447 */ 448 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 449 450 #ifdef KDTRACE_HOOKS 451 int reason = CLD_EXITED; 452 if (WCOREDUMP(rv)) 453 reason = CLD_DUMPED; 454 else if (WIFSIGNALED(rv)) 455 reason = CLD_KILLED; 456 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 457 #endif 458 459 /* 460 * Just delete all entries in the p_klist. At this point we won't 461 * report any more events, and there are nasty race conditions that 462 * can beat us if we don't. 463 */ 464 knlist_clear(&p->p_klist, 1); 465 466 /* 467 * If this is a process with a descriptor, we may not need to deliver 468 * a signal to the parent. proctree_lock is held over 469 * procdesc_exit() to serialize concurrent calls to close() and 470 * exit(). 471 */ 472 #ifdef PROCDESC 473 if (p->p_procdesc == NULL || procdesc_exit(p)) { 474 #endif 475 /* 476 * Notify parent that we're gone. If parent has the 477 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN, 478 * notify process 1 instead (and hope it will handle this 479 * situation). 480 */ 481 PROC_LOCK(p->p_pptr); 482 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 483 if (p->p_pptr->p_sigacts->ps_flag & 484 (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 485 struct proc *pp; 486 487 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 488 pp = p->p_pptr; 489 PROC_UNLOCK(pp); 490 proc_reparent(p, initproc); 491 p->p_sigparent = SIGCHLD; 492 PROC_LOCK(p->p_pptr); 493 494 /* 495 * Notify parent, so in case he was wait(2)ing or 496 * executing waitpid(2) with our pid, he will 497 * continue. 498 */ 499 wakeup(pp); 500 } else 501 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 502 503 if (p->p_pptr == initproc) 504 kern_psignal(p->p_pptr, SIGCHLD); 505 else if (p->p_sigparent != 0) { 506 if (p->p_sigparent == SIGCHLD) 507 childproc_exited(p); 508 else /* LINUX thread */ 509 kern_psignal(p->p_pptr, p->p_sigparent); 510 } 511 #ifdef PROCDESC 512 } else 513 PROC_LOCK(p->p_pptr); 514 #endif 515 sx_xunlock(&proctree_lock); 516 517 /* 518 * The state PRS_ZOMBIE prevents other proesses from sending 519 * signal to the process, to avoid memory leak, we free memory 520 * for signal queue at the time when the state is set. 521 */ 522 sigqueue_flush(&p->p_sigqueue); 523 sigqueue_flush(&td->td_sigqueue); 524 525 /* 526 * We have to wait until after acquiring all locks before 527 * changing p_state. We need to avoid all possible context 528 * switches (including ones from blocking on a mutex) while 529 * marked as a zombie. We also have to set the zombie state 530 * before we release the parent process' proc lock to avoid 531 * a lost wakeup. So, we first call wakeup, then we grab the 532 * sched lock, update the state, and release the parent process' 533 * proc lock. 534 */ 535 wakeup(p->p_pptr); 536 cv_broadcast(&p->p_pwait); 537 sched_exit(p->p_pptr, td); 538 PROC_SLOCK(p); 539 p->p_state = PRS_ZOMBIE; 540 PROC_UNLOCK(p->p_pptr); 541 542 /* 543 * Hopefully no one will try to deliver a signal to the process this 544 * late in the game. 545 */ 546 knlist_destroy(&p->p_klist); 547 548 /* 549 * Save our children's rusage information in our exit rusage. 550 */ 551 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 552 553 /* 554 * Make sure the scheduler takes this thread out of its tables etc. 555 * This will also release this thread's reference to the ucred. 556 * Other thread parts to release include pcb bits and such. 557 */ 558 thread_exit(); 559 } 560 561 562 #ifndef _SYS_SYSPROTO_H_ 563 struct abort2_args { 564 char *why; 565 int nargs; 566 void **args; 567 }; 568 #endif 569 570 int 571 sys_abort2(struct thread *td, struct abort2_args *uap) 572 { 573 struct proc *p = td->td_proc; 574 struct sbuf *sb; 575 void *uargs[16]; 576 int error, i, sig; 577 578 /* 579 * Do it right now so we can log either proper call of abort2(), or 580 * note, that invalid argument was passed. 512 is big enough to 581 * handle 16 arguments' descriptions with additional comments. 582 */ 583 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 584 sbuf_clear(sb); 585 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 586 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 587 /* 588 * Since we can't return from abort2(), send SIGKILL in cases, where 589 * abort2() was called improperly 590 */ 591 sig = SIGKILL; 592 /* Prevent from DoSes from user-space. */ 593 if (uap->nargs < 0 || uap->nargs > 16) 594 goto out; 595 if (uap->nargs > 0) { 596 if (uap->args == NULL) 597 goto out; 598 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 599 if (error != 0) 600 goto out; 601 } 602 /* 603 * Limit size of 'reason' string to 128. Will fit even when 604 * maximal number of arguments was chosen to be logged. 605 */ 606 if (uap->why != NULL) { 607 error = sbuf_copyin(sb, uap->why, 128); 608 if (error < 0) 609 goto out; 610 } else { 611 sbuf_printf(sb, "(null)"); 612 } 613 if (uap->nargs > 0) { 614 sbuf_printf(sb, "("); 615 for (i = 0;i < uap->nargs; i++) 616 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 617 sbuf_printf(sb, ")"); 618 } 619 /* 620 * Final stage: arguments were proper, string has been 621 * successfully copied from userspace, and copying pointers 622 * from user-space succeed. 623 */ 624 sig = SIGABRT; 625 out: 626 if (sig == SIGKILL) { 627 sbuf_trim(sb); 628 sbuf_printf(sb, " (Reason text inaccessible)"); 629 } 630 sbuf_cat(sb, "\n"); 631 sbuf_finish(sb); 632 log(LOG_INFO, "%s", sbuf_data(sb)); 633 sbuf_delete(sb); 634 exit1(td, W_EXITCODE(0, sig)); 635 return (0); 636 } 637 638 639 #ifdef COMPAT_43 640 /* 641 * The dirty work is handled by kern_wait(). 642 */ 643 int 644 owait(struct thread *td, struct owait_args *uap __unused) 645 { 646 int error, status; 647 648 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 649 if (error == 0) 650 td->td_retval[1] = status; 651 return (error); 652 } 653 #endif /* COMPAT_43 */ 654 655 /* 656 * The dirty work is handled by kern_wait(). 657 */ 658 int 659 sys_wait4(struct thread *td, struct wait_args *uap) 660 { 661 struct rusage ru, *rup; 662 int error, status; 663 664 if (uap->rusage != NULL) 665 rup = &ru; 666 else 667 rup = NULL; 668 error = kern_wait(td, uap->pid, &status, uap->options, rup); 669 if (uap->status != NULL && error == 0) 670 error = copyout(&status, uap->status, sizeof(status)); 671 if (uap->rusage != NULL && error == 0) 672 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 673 return (error); 674 } 675 676 /* 677 * Reap the remains of a zombie process and optionally return status and 678 * rusage. Asserts and will release both the proctree_lock and the process 679 * lock as part of its work. 680 */ 681 void 682 proc_reap(struct thread *td, struct proc *p, int *status, int options, 683 struct rusage *rusage) 684 { 685 struct proc *q, *t; 686 687 sx_assert(&proctree_lock, SA_XLOCKED); 688 PROC_LOCK_ASSERT(p, MA_OWNED); 689 PROC_SLOCK_ASSERT(p, MA_OWNED); 690 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 691 692 q = td->td_proc; 693 if (rusage) { 694 *rusage = p->p_ru; 695 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 696 } 697 PROC_SUNLOCK(p); 698 td->td_retval[0] = p->p_pid; 699 if (status) 700 *status = p->p_xstat; /* convert to int */ 701 if (options & WNOWAIT) { 702 /* 703 * Only poll, returning the status. Caller does not wish to 704 * release the proc struct just yet. 705 */ 706 PROC_UNLOCK(p); 707 sx_xunlock(&proctree_lock); 708 return; 709 } 710 711 PROC_LOCK(q); 712 sigqueue_take(p->p_ksi); 713 PROC_UNLOCK(q); 714 PROC_UNLOCK(p); 715 716 /* 717 * If we got the child via a ptrace 'attach', we need to give it back 718 * to the old parent. 719 */ 720 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 721 PROC_LOCK(p); 722 proc_reparent(p, t); 723 p->p_pptr->p_dbg_child--; 724 p->p_oppid = 0; 725 PROC_UNLOCK(p); 726 pksignal(t, SIGCHLD, p->p_ksi); 727 wakeup(t); 728 cv_broadcast(&p->p_pwait); 729 PROC_UNLOCK(t); 730 sx_xunlock(&proctree_lock); 731 return; 732 } 733 734 /* 735 * Remove other references to this process to ensure we have an 736 * exclusive reference. 737 */ 738 sx_xlock(&allproc_lock); 739 LIST_REMOVE(p, p_list); /* off zombproc */ 740 sx_xunlock(&allproc_lock); 741 LIST_REMOVE(p, p_sibling); 742 leavepgrp(p); 743 #ifdef PROCDESC 744 if (p->p_procdesc != NULL) 745 procdesc_reap(p); 746 #endif 747 sx_xunlock(&proctree_lock); 748 749 /* 750 * As a side effect of this lock, we know that all other writes to 751 * this proc are visible now, so no more locking is needed for p. 752 */ 753 PROC_LOCK(p); 754 p->p_xstat = 0; /* XXX: why? */ 755 PROC_UNLOCK(p); 756 PROC_LOCK(q); 757 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 758 PROC_UNLOCK(q); 759 760 /* 761 * Decrement the count of procs running with this uid. 762 */ 763 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 764 765 /* 766 * Destroy resource accounting information associated with the process. 767 */ 768 #ifdef RACCT 769 PROC_LOCK(p); 770 racct_sub(p, RACCT_NPROC, 1); 771 PROC_UNLOCK(p); 772 #endif 773 racct_proc_exit(p); 774 775 /* 776 * Free credentials, arguments, and sigacts. 777 */ 778 crfree(p->p_ucred); 779 p->p_ucred = NULL; 780 pargs_drop(p->p_args); 781 p->p_args = NULL; 782 sigacts_free(p->p_sigacts); 783 p->p_sigacts = NULL; 784 785 /* 786 * Do any thread-system specific cleanups. 787 */ 788 thread_wait(p); 789 790 /* 791 * Give vm and machine-dependent layer a chance to free anything that 792 * cpu_exit couldn't release while still running in process context. 793 */ 794 vm_waitproc(p); 795 #ifdef MAC 796 mac_proc_destroy(p); 797 #endif 798 KASSERT(FIRST_THREAD_IN_PROC(p), 799 ("proc_reap: no residual thread!")); 800 uma_zfree(proc_zone, p); 801 sx_xlock(&allproc_lock); 802 nprocs--; 803 sx_xunlock(&allproc_lock); 804 } 805 806 int 807 kern_wait(struct thread *td, pid_t pid, int *status, int options, 808 struct rusage *rusage) 809 { 810 struct proc *p, *q; 811 int error, nfound; 812 813 AUDIT_ARG_PID(pid); 814 AUDIT_ARG_VALUE(options); 815 816 q = td->td_proc; 817 if (pid == 0) { 818 PROC_LOCK(q); 819 pid = -q->p_pgid; 820 PROC_UNLOCK(q); 821 } 822 /* If we don't know the option, just return. */ 823 if (options & ~(WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE)) 824 return (EINVAL); 825 loop: 826 if (q->p_flag & P_STATCHILD) { 827 PROC_LOCK(q); 828 q->p_flag &= ~P_STATCHILD; 829 PROC_UNLOCK(q); 830 } 831 nfound = 0; 832 sx_xlock(&proctree_lock); 833 LIST_FOREACH(p, &q->p_children, p_sibling) { 834 PROC_LOCK(p); 835 if (pid != WAIT_ANY && 836 p->p_pid != pid && p->p_pgid != -pid) { 837 PROC_UNLOCK(p); 838 continue; 839 } 840 if (p_canwait(td, p)) { 841 PROC_UNLOCK(p); 842 continue; 843 } 844 845 /* 846 * This special case handles a kthread spawned by linux_clone 847 * (see linux_misc.c). The linux_wait4 and linux_waitpid 848 * functions need to be able to distinguish between waiting 849 * on a process and waiting on a thread. It is a thread if 850 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 851 * signifies we want to wait for threads and not processes. 852 */ 853 if ((p->p_sigparent != SIGCHLD) ^ 854 ((options & WLINUXCLONE) != 0)) { 855 PROC_UNLOCK(p); 856 continue; 857 } 858 859 nfound++; 860 PROC_SLOCK(p); 861 if (p->p_state == PRS_ZOMBIE) { 862 proc_reap(td, p, status, options, rusage); 863 return (0); 864 } 865 if ((p->p_flag & P_STOPPED_SIG) && 866 (p->p_suspcount == p->p_numthreads) && 867 (p->p_flag & P_WAITED) == 0 && 868 (p->p_flag & P_TRACED || options & WUNTRACED)) { 869 PROC_SUNLOCK(p); 870 p->p_flag |= P_WAITED; 871 sx_xunlock(&proctree_lock); 872 td->td_retval[0] = p->p_pid; 873 if (status) 874 *status = W_STOPCODE(p->p_xstat); 875 876 PROC_LOCK(q); 877 sigqueue_take(p->p_ksi); 878 PROC_UNLOCK(q); 879 PROC_UNLOCK(p); 880 881 return (0); 882 } 883 PROC_SUNLOCK(p); 884 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 885 sx_xunlock(&proctree_lock); 886 td->td_retval[0] = p->p_pid; 887 p->p_flag &= ~P_CONTINUED; 888 889 PROC_LOCK(q); 890 sigqueue_take(p->p_ksi); 891 PROC_UNLOCK(q); 892 PROC_UNLOCK(p); 893 894 if (status) 895 *status = SIGCONT; 896 return (0); 897 } 898 PROC_UNLOCK(p); 899 } 900 if (nfound == 0) { 901 sx_xunlock(&proctree_lock); 902 if (td->td_proc->p_dbg_child) 903 return (0); 904 else 905 return (ECHILD); 906 } 907 if (options & WNOHANG) { 908 sx_xunlock(&proctree_lock); 909 td->td_retval[0] = 0; 910 return (0); 911 } 912 PROC_LOCK(q); 913 sx_xunlock(&proctree_lock); 914 if (q->p_flag & P_STATCHILD) { 915 q->p_flag &= ~P_STATCHILD; 916 error = 0; 917 } else 918 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 919 PROC_UNLOCK(q); 920 if (error) 921 return (error); 922 goto loop; 923 } 924 925 /* 926 * Make process 'parent' the new parent of process 'child'. 927 * Must be called with an exclusive hold of proctree lock. 928 */ 929 void 930 proc_reparent(struct proc *child, struct proc *parent) 931 { 932 933 sx_assert(&proctree_lock, SX_XLOCKED); 934 PROC_LOCK_ASSERT(child, MA_OWNED); 935 if (child->p_pptr == parent) 936 return; 937 938 PROC_LOCK(child->p_pptr); 939 sigqueue_take(child->p_ksi); 940 PROC_UNLOCK(child->p_pptr); 941 LIST_REMOVE(child, p_sibling); 942 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 943 child->p_pptr = parent; 944 }
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