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 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/sysproto.h> 46 #include <sys/capsicum.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/procdesc.h> 54 #include <sys/pioctl.h> 55 #include <sys/jail.h> 56 #include <sys/tty.h> 57 #include <sys/wait.h> 58 #include <sys/vmmeter.h> 59 #include <sys/vnode.h> 60 #include <sys/racct.h> 61 #include <sys/resourcevar.h> 62 #include <sys/sbuf.h> 63 #include <sys/signalvar.h> 64 #include <sys/sched.h> 65 #include <sys/sx.h> 66 #include <sys/syscallsubr.h> 67 #include <sys/syslog.h> 68 #include <sys/ptrace.h> 69 #include <sys/acct.h> /* for acct_process() function prototype */ 70 #include <sys/filedesc.h> 71 #include <sys/sdt.h> 72 #include <sys/shm.h> 73 #include <sys/sem.h> 74 #ifdef KTRACE 75 #include <sys/ktrace.h> 76 #endif 77 78 #include <security/audit/audit.h> 79 #include <security/mac/mac_framework.h> 80 81 #include <vm/vm.h> 82 #include <vm/vm_extern.h> 83 #include <vm/vm_param.h> 84 #include <vm/pmap.h> 85 #include <vm/vm_map.h> 86 #include <vm/vm_page.h> 87 #include <vm/uma.h> 88 89 #ifdef KDTRACE_HOOKS 90 #include <sys/dtrace_bsd.h> 91 dtrace_execexit_func_t dtrace_fasttrap_exit; 92 #endif 93 94 SDT_PROVIDER_DECLARE(proc); 95 SDT_PROBE_DEFINE1(proc, kernel, , exit, "int"); 96 97 /* Hook for NFS teardown procedure. */ 98 void (*nlminfo_release_p)(struct proc *p); 99 100 static void 101 clear_orphan(struct proc *p) 102 { 103 104 PROC_LOCK_ASSERT(p, MA_OWNED); 105 106 if (p->p_flag & P_ORPHAN) { 107 LIST_REMOVE(p, p_orphan); 108 p->p_flag &= ~P_ORPHAN; 109 } 110 } 111 112 /* 113 * exit -- death of process. 114 */ 115 void 116 sys_sys_exit(struct thread *td, struct sys_exit_args *uap) 117 { 118 119 exit1(td, W_EXITCODE(uap->rval, 0)); 120 /* NOTREACHED */ 121 } 122 123 /* 124 * Exit: deallocate address space and other resources, change proc state to 125 * zombie, and unlink proc from allproc and parent's lists. Save exit status 126 * and rusage for wait(). Check for child processes and orphan them. 127 */ 128 void 129 exit1(struct thread *td, int rv) 130 { 131 struct proc *p, *nq, *q; 132 struct vnode *vtmp; 133 struct vnode *ttyvp = NULL; 134 struct plimit *plim; 135 136 mtx_assert(&Giant, MA_NOTOWNED); 137 138 p = td->td_proc; 139 /* 140 * XXX in case we're rebooting we just let init die in order to 141 * work around an unsolved stack overflow seen very late during 142 * shutdown on sparc64 when the gmirror worker process exists. 143 */ 144 if (p == initproc && rebooting == 0) { 145 printf("init died (signal %d, exit %d)\n", 146 WTERMSIG(rv), WEXITSTATUS(rv)); 147 panic("Going nowhere without my init!"); 148 } 149 150 /* 151 * MUST abort all other threads before proceeding past here. 152 */ 153 PROC_LOCK(p); 154 while (p->p_flag & P_HADTHREADS) { 155 /* 156 * First check if some other thread got here before us. 157 * If so, act appropriately: exit or suspend. 158 */ 159 thread_suspend_check(0); 160 161 /* 162 * Kill off the other threads. This requires 163 * some co-operation from other parts of the kernel 164 * so it may not be instantaneous. With this state set 165 * any thread entering the kernel from userspace will 166 * thread_exit() in trap(). Any thread attempting to 167 * sleep will return immediately with EINTR or EWOULDBLOCK 168 * which will hopefully force them to back out to userland 169 * freeing resources as they go. Any thread attempting 170 * to return to userland will thread_exit() from userret(). 171 * thread_exit() will unsuspend us when the last of the 172 * other threads exits. 173 * If there is already a thread singler after resumption, 174 * calling thread_single will fail; in that case, we just 175 * re-check all suspension request, the thread should 176 * either be suspended there or exit. 177 */ 178 if (!thread_single(SINGLE_EXIT)) 179 break; 180 181 /* 182 * All other activity in this process is now stopped. 183 * Threading support has been turned off. 184 */ 185 } 186 KASSERT(p->p_numthreads == 1, 187 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 188 racct_sub(p, RACCT_NTHR, 1); 189 /* 190 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 191 * on our vmspace, so we should block below until they have 192 * released their reference to us. Note that if they have 193 * requested S_EXIT stops we will block here until they ack 194 * via PIOCCONT. 195 */ 196 _STOPEVENT(p, S_EXIT, rv); 197 198 /* 199 * Ignore any pending request to stop due to a stop signal. 200 * Once P_WEXIT is set, future requests will be ignored as 201 * well. 202 */ 203 p->p_flag &= ~P_STOPPED_SIG; 204 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped")); 205 206 /* 207 * Note that we are exiting and do another wakeup of anyone in 208 * PIOCWAIT in case they aren't listening for S_EXIT stops or 209 * decided to wait again after we told them we are exiting. 210 */ 211 p->p_flag |= P_WEXIT; 212 wakeup(&p->p_stype); 213 214 /* 215 * Wait for any processes that have a hold on our vmspace to 216 * release their reference. 217 */ 218 while (p->p_lock > 0) 219 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 220 221 p->p_xstat = rv; /* Let event handler change exit status */ 222 PROC_UNLOCK(p); 223 /* Drain the limit callout while we don't have the proc locked */ 224 callout_drain(&p->p_limco); 225 226 #ifdef AUDIT 227 /* 228 * The Sun BSM exit token contains two components: an exit status as 229 * passed to exit(), and a return value to indicate what sort of exit 230 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 231 * what the return value is. 232 */ 233 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0); 234 AUDIT_SYSCALL_EXIT(0, td); 235 #endif 236 237 /* Are we a task leader? */ 238 if (p == p->p_leader) { 239 mtx_lock(&ppeers_lock); 240 q = p->p_peers; 241 while (q != NULL) { 242 PROC_LOCK(q); 243 kern_psignal(q, SIGKILL); 244 PROC_UNLOCK(q); 245 q = q->p_peers; 246 } 247 while (p->p_peers != NULL) 248 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 249 mtx_unlock(&ppeers_lock); 250 } 251 252 /* 253 * Check if any loadable modules need anything done at process exit. 254 * E.g. SYSV IPC stuff 255 * XXX what if one of these generates an error? 256 */ 257 EVENTHANDLER_INVOKE(process_exit, p); 258 259 /* 260 * If parent is waiting for us to exit or exec, 261 * P_PPWAIT is set; we will wakeup the parent below. 262 */ 263 PROC_LOCK(p); 264 rv = p->p_xstat; /* Event handler could change exit status */ 265 stopprofclock(p); 266 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE); 267 268 /* 269 * Stop the real interval timer. If the handler is currently 270 * executing, prevent it from rearming itself and let it finish. 271 */ 272 if (timevalisset(&p->p_realtimer.it_value) && 273 callout_stop(&p->p_itcallout) == 0) { 274 timevalclear(&p->p_realtimer.it_interval); 275 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 276 KASSERT(!timevalisset(&p->p_realtimer.it_value), 277 ("realtime timer is still armed")); 278 } 279 PROC_UNLOCK(p); 280 281 /* 282 * Reset any sigio structures pointing to us as a result of 283 * F_SETOWN with our pid. 284 */ 285 funsetownlst(&p->p_sigiolst); 286 287 /* 288 * If this process has an nlminfo data area (for lockd), release it 289 */ 290 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 291 (*nlminfo_release_p)(p); 292 293 /* 294 * Close open files and release open-file table. 295 * This may block! 296 */ 297 fdescfree(td); 298 299 /* 300 * If this thread tickled GEOM, we need to wait for the giggling to 301 * stop before we return to userland 302 */ 303 if (td->td_pflags & TDP_GEOM) 304 g_waitidle(); 305 306 /* 307 * Remove ourself from our leader's peer list and wake our leader. 308 */ 309 mtx_lock(&ppeers_lock); 310 if (p->p_leader->p_peers) { 311 q = p->p_leader; 312 while (q->p_peers != p) 313 q = q->p_peers; 314 q->p_peers = p->p_peers; 315 wakeup(p->p_leader); 316 } 317 mtx_unlock(&ppeers_lock); 318 319 vmspace_exit(td); 320 321 sx_xlock(&proctree_lock); 322 if (SESS_LEADER(p)) { 323 struct session *sp = p->p_session; 324 struct tty *tp; 325 326 /* 327 * s_ttyp is not zero'd; we use this to indicate that 328 * the session once had a controlling terminal. (for 329 * logging and informational purposes) 330 */ 331 SESS_LOCK(sp); 332 ttyvp = sp->s_ttyvp; 333 tp = sp->s_ttyp; 334 sp->s_ttyvp = NULL; 335 sp->s_ttydp = NULL; 336 sp->s_leader = NULL; 337 SESS_UNLOCK(sp); 338 339 /* 340 * Signal foreground pgrp and revoke access to 341 * controlling terminal if it has not been revoked 342 * already. 343 * 344 * Because the TTY may have been revoked in the mean 345 * time and could already have a new session associated 346 * with it, make sure we don't send a SIGHUP to a 347 * foreground process group that does not belong to this 348 * session. 349 */ 350 351 if (tp != NULL) { 352 tty_lock(tp); 353 if (tp->t_session == sp) 354 tty_signal_pgrp(tp, SIGHUP); 355 tty_unlock(tp); 356 } 357 358 if (ttyvp != NULL) { 359 sx_xunlock(&proctree_lock); 360 if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) { 361 VOP_REVOKE(ttyvp, REVOKEALL); 362 VOP_UNLOCK(ttyvp, 0); 363 } 364 sx_xlock(&proctree_lock); 365 } 366 } 367 fixjobc(p, p->p_pgrp, 0); 368 sx_xunlock(&proctree_lock); 369 (void)acct_process(td); 370 371 /* Release the TTY now we've unlocked everything. */ 372 if (ttyvp != NULL) 373 vrele(ttyvp); 374 #ifdef KTRACE 375 ktrprocexit(td); 376 #endif 377 /* 378 * Release reference to text vnode 379 */ 380 if ((vtmp = p->p_textvp) != NULL) { 381 p->p_textvp = NULL; 382 vrele(vtmp); 383 } 384 385 /* 386 * Release our limits structure. 387 */ 388 plim = p->p_limit; 389 p->p_limit = NULL; 390 lim_free(plim); 391 392 tidhash_remove(td); 393 394 /* 395 * Remove proc from allproc queue and pidhash chain. 396 * Place onto zombproc. Unlink from parent's child list. 397 */ 398 sx_xlock(&allproc_lock); 399 LIST_REMOVE(p, p_list); 400 LIST_INSERT_HEAD(&zombproc, p, p_list); 401 LIST_REMOVE(p, p_hash); 402 sx_xunlock(&allproc_lock); 403 404 /* 405 * Call machine-dependent code to release any 406 * machine-dependent resources other than the address space. 407 * The address space is released by "vmspace_exitfree(p)" in 408 * vm_waitproc(). 409 */ 410 cpu_exit(td); 411 412 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 413 414 /* 415 * Reparent all of our children to init. 416 */ 417 sx_xlock(&proctree_lock); 418 q = LIST_FIRST(&p->p_children); 419 if (q != NULL) /* only need this if any child is S_ZOMB */ 420 wakeup(initproc); 421 for (; q != NULL; q = nq) { 422 nq = LIST_NEXT(q, p_sibling); 423 PROC_LOCK(q); 424 proc_reparent(q, initproc); 425 q->p_sigparent = SIGCHLD; 426 /* 427 * Traced processes are killed 428 * since their existence means someone is screwing up. 429 */ 430 if (q->p_flag & P_TRACED) { 431 struct thread *temp; 432 433 /* 434 * Since q was found on our children list, the 435 * proc_reparent() call moved q to the orphan 436 * list due to present P_TRACED flag. Clear 437 * orphan link for q now while q is locked. 438 */ 439 clear_orphan(q); 440 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 441 FOREACH_THREAD_IN_PROC(q, temp) 442 temp->td_dbgflags &= ~TDB_SUSPEND; 443 kern_psignal(q, SIGKILL); 444 } 445 PROC_UNLOCK(q); 446 } 447 448 /* 449 * Also get rid of our orphans. 450 */ 451 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) { 452 PROC_LOCK(q); 453 clear_orphan(q); 454 PROC_UNLOCK(q); 455 } 456 457 /* Save exit status. */ 458 PROC_LOCK(p); 459 p->p_xthread = td; 460 461 /* Tell the prison that we are gone. */ 462 prison_proc_free(p->p_ucred->cr_prison); 463 464 #ifdef KDTRACE_HOOKS 465 /* 466 * Tell the DTrace fasttrap provider about the exit if it 467 * has declared an interest. 468 */ 469 if (dtrace_fasttrap_exit) 470 dtrace_fasttrap_exit(p); 471 #endif 472 473 /* 474 * Notify interested parties of our demise. 475 */ 476 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 477 478 #ifdef KDTRACE_HOOKS 479 int reason = CLD_EXITED; 480 if (WCOREDUMP(rv)) 481 reason = CLD_DUMPED; 482 else if (WIFSIGNALED(rv)) 483 reason = CLD_KILLED; 484 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 485 #endif 486 487 /* 488 * Just delete all entries in the p_klist. At this point we won't 489 * report any more events, and there are nasty race conditions that 490 * can beat us if we don't. 491 */ 492 knlist_clear(&p->p_klist, 1); 493 494 /* 495 * If this is a process with a descriptor, we may not need to deliver 496 * a signal to the parent. proctree_lock is held over 497 * procdesc_exit() to serialize concurrent calls to close() and 498 * exit(). 499 */ 500 if (p->p_procdesc == NULL || procdesc_exit(p)) { 501 /* 502 * Notify parent that we're gone. If parent has the 503 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN, 504 * notify process 1 instead (and hope it will handle this 505 * situation). 506 */ 507 PROC_LOCK(p->p_pptr); 508 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 509 if (p->p_pptr->p_sigacts->ps_flag & 510 (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 511 struct proc *pp; 512 513 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 514 pp = p->p_pptr; 515 PROC_UNLOCK(pp); 516 proc_reparent(p, initproc); 517 p->p_sigparent = SIGCHLD; 518 PROC_LOCK(p->p_pptr); 519 520 /* 521 * Notify parent, so in case he was wait(2)ing or 522 * executing waitpid(2) with our pid, he will 523 * continue. 524 */ 525 wakeup(pp); 526 } else 527 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 528 529 if (p->p_pptr == initproc) 530 kern_psignal(p->p_pptr, SIGCHLD); 531 else if (p->p_sigparent != 0) { 532 if (p->p_sigparent == SIGCHLD) 533 childproc_exited(p); 534 else /* LINUX thread */ 535 kern_psignal(p->p_pptr, p->p_sigparent); 536 } 537 } else 538 PROC_LOCK(p->p_pptr); 539 sx_xunlock(&proctree_lock); 540 541 /* 542 * The state PRS_ZOMBIE prevents other proesses from sending 543 * signal to the process, to avoid memory leak, we free memory 544 * for signal queue at the time when the state is set. 545 */ 546 sigqueue_flush(&p->p_sigqueue); 547 sigqueue_flush(&td->td_sigqueue); 548 549 /* 550 * We have to wait until after acquiring all locks before 551 * changing p_state. We need to avoid all possible context 552 * switches (including ones from blocking on a mutex) while 553 * marked as a zombie. We also have to set the zombie state 554 * before we release the parent process' proc lock to avoid 555 * a lost wakeup. So, we first call wakeup, then we grab the 556 * sched lock, update the state, and release the parent process' 557 * proc lock. 558 */ 559 wakeup(p->p_pptr); 560 cv_broadcast(&p->p_pwait); 561 sched_exit(p->p_pptr, td); 562 PROC_SLOCK(p); 563 p->p_state = PRS_ZOMBIE; 564 PROC_UNLOCK(p->p_pptr); 565 566 /* 567 * Hopefully no one will try to deliver a signal to the process this 568 * late in the game. 569 */ 570 knlist_destroy(&p->p_klist); 571 572 /* 573 * Save our children's rusage information in our exit rusage. 574 */ 575 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 576 577 /* 578 * Make sure the scheduler takes this thread out of its tables etc. 579 * This will also release this thread's reference to the ucred. 580 * Other thread parts to release include pcb bits and such. 581 */ 582 thread_exit(); 583 } 584 585 586 #ifndef _SYS_SYSPROTO_H_ 587 struct abort2_args { 588 char *why; 589 int nargs; 590 void **args; 591 }; 592 #endif 593 594 int 595 sys_abort2(struct thread *td, struct abort2_args *uap) 596 { 597 struct proc *p = td->td_proc; 598 struct sbuf *sb; 599 void *uargs[16]; 600 int error, i, sig; 601 602 /* 603 * Do it right now so we can log either proper call of abort2(), or 604 * note, that invalid argument was passed. 512 is big enough to 605 * handle 16 arguments' descriptions with additional comments. 606 */ 607 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 608 sbuf_clear(sb); 609 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 610 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 611 /* 612 * Since we can't return from abort2(), send SIGKILL in cases, where 613 * abort2() was called improperly 614 */ 615 sig = SIGKILL; 616 /* Prevent from DoSes from user-space. */ 617 if (uap->nargs < 0 || uap->nargs > 16) 618 goto out; 619 if (uap->nargs > 0) { 620 if (uap->args == NULL) 621 goto out; 622 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 623 if (error != 0) 624 goto out; 625 } 626 /* 627 * Limit size of 'reason' string to 128. Will fit even when 628 * maximal number of arguments was chosen to be logged. 629 */ 630 if (uap->why != NULL) { 631 error = sbuf_copyin(sb, uap->why, 128); 632 if (error < 0) 633 goto out; 634 } else { 635 sbuf_printf(sb, "(null)"); 636 } 637 if (uap->nargs > 0) { 638 sbuf_printf(sb, "("); 639 for (i = 0;i < uap->nargs; i++) 640 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 641 sbuf_printf(sb, ")"); 642 } 643 /* 644 * Final stage: arguments were proper, string has been 645 * successfully copied from userspace, and copying pointers 646 * from user-space succeed. 647 */ 648 sig = SIGABRT; 649 out: 650 if (sig == SIGKILL) { 651 sbuf_trim(sb); 652 sbuf_printf(sb, " (Reason text inaccessible)"); 653 } 654 sbuf_cat(sb, "\n"); 655 sbuf_finish(sb); 656 log(LOG_INFO, "%s", sbuf_data(sb)); 657 sbuf_delete(sb); 658 exit1(td, W_EXITCODE(0, sig)); 659 return (0); 660 } 661 662 663 #ifdef COMPAT_43 664 /* 665 * The dirty work is handled by kern_wait(). 666 */ 667 int 668 owait(struct thread *td, struct owait_args *uap __unused) 669 { 670 int error, status; 671 672 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 673 if (error == 0) 674 td->td_retval[1] = status; 675 return (error); 676 } 677 #endif /* COMPAT_43 */ 678 679 /* 680 * The dirty work is handled by kern_wait(). 681 */ 682 int 683 sys_wait4(struct thread *td, struct wait4_args *uap) 684 { 685 struct rusage ru, *rup; 686 int error, status; 687 688 if (uap->rusage != NULL) 689 rup = &ru; 690 else 691 rup = NULL; 692 error = kern_wait(td, uap->pid, &status, uap->options, rup); 693 if (uap->status != NULL && error == 0) 694 error = copyout(&status, uap->status, sizeof(status)); 695 if (uap->rusage != NULL && error == 0) 696 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 697 return (error); 698 } 699 700 int 701 sys_wait6(struct thread *td, struct wait6_args *uap) 702 { 703 struct __wrusage wru, *wrup; 704 siginfo_t si, *sip; 705 idtype_t idtype; 706 id_t id; 707 int error, status; 708 709 idtype = uap->idtype; 710 id = uap->id; 711 712 if (uap->wrusage != NULL) 713 wrup = &wru; 714 else 715 wrup = NULL; 716 717 if (uap->info != NULL) { 718 sip = &si; 719 bzero(sip, sizeof(*sip)); 720 } else 721 sip = NULL; 722 723 /* 724 * We expect all callers of wait6() to know about WEXITED and 725 * WTRAPPED. 726 */ 727 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip); 728 729 if (uap->status != NULL && error == 0) 730 error = copyout(&status, uap->status, sizeof(status)); 731 if (uap->wrusage != NULL && error == 0) 732 error = copyout(&wru, uap->wrusage, sizeof(wru)); 733 if (uap->info != NULL && error == 0) 734 error = copyout(&si, uap->info, sizeof(si)); 735 return (error); 736 } 737 738 /* 739 * Reap the remains of a zombie process and optionally return status and 740 * rusage. Asserts and will release both the proctree_lock and the process 741 * lock as part of its work. 742 */ 743 void 744 proc_reap(struct thread *td, struct proc *p, int *status, int options) 745 { 746 struct proc *q, *t; 747 748 sx_assert(&proctree_lock, SA_XLOCKED); 749 PROC_LOCK_ASSERT(p, MA_OWNED); 750 PROC_SLOCK_ASSERT(p, MA_OWNED); 751 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 752 753 q = td->td_proc; 754 755 PROC_SUNLOCK(p); 756 td->td_retval[0] = p->p_pid; 757 if (status) 758 *status = p->p_xstat; /* convert to int */ 759 if (options & WNOWAIT) { 760 /* 761 * Only poll, returning the status. Caller does not wish to 762 * release the proc struct just yet. 763 */ 764 PROC_UNLOCK(p); 765 sx_xunlock(&proctree_lock); 766 return; 767 } 768 769 PROC_LOCK(q); 770 sigqueue_take(p->p_ksi); 771 PROC_UNLOCK(q); 772 PROC_UNLOCK(p); 773 774 /* 775 * If we got the child via a ptrace 'attach', we need to give it back 776 * to the old parent. 777 */ 778 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 779 PROC_LOCK(p); 780 proc_reparent(p, t); 781 p->p_oppid = 0; 782 PROC_UNLOCK(p); 783 pksignal(t, SIGCHLD, p->p_ksi); 784 wakeup(t); 785 cv_broadcast(&p->p_pwait); 786 PROC_UNLOCK(t); 787 sx_xunlock(&proctree_lock); 788 return; 789 } 790 791 /* 792 * Remove other references to this process to ensure we have an 793 * exclusive reference. 794 */ 795 sx_xlock(&allproc_lock); 796 LIST_REMOVE(p, p_list); /* off zombproc */ 797 sx_xunlock(&allproc_lock); 798 LIST_REMOVE(p, p_sibling); 799 PROC_LOCK(p); 800 clear_orphan(p); 801 PROC_UNLOCK(p); 802 leavepgrp(p); 803 if (p->p_procdesc != NULL) 804 procdesc_reap(p); 805 sx_xunlock(&proctree_lock); 806 807 /* 808 * As a side effect of this lock, we know that all other writes to 809 * this proc are visible now, so no more locking is needed for p. 810 */ 811 PROC_LOCK(p); 812 p->p_xstat = 0; /* XXX: why? */ 813 PROC_UNLOCK(p); 814 PROC_LOCK(q); 815 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 816 PROC_UNLOCK(q); 817 818 /* 819 * Decrement the count of procs running with this uid. 820 */ 821 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 822 823 /* 824 * Destroy resource accounting information associated with the process. 825 */ 826 #ifdef RACCT 827 PROC_LOCK(p); 828 racct_sub(p, RACCT_NPROC, 1); 829 PROC_UNLOCK(p); 830 #endif 831 racct_proc_exit(p); 832 833 /* 834 * Free credentials, arguments, and sigacts. 835 */ 836 crfree(p->p_ucred); 837 p->p_ucred = NULL; 838 pargs_drop(p->p_args); 839 p->p_args = NULL; 840 sigacts_free(p->p_sigacts); 841 p->p_sigacts = NULL; 842 843 /* 844 * Do any thread-system specific cleanups. 845 */ 846 thread_wait(p); 847 848 /* 849 * Give vm and machine-dependent layer a chance to free anything that 850 * cpu_exit couldn't release while still running in process context. 851 */ 852 vm_waitproc(p); 853 #ifdef MAC 854 mac_proc_destroy(p); 855 #endif 856 KASSERT(FIRST_THREAD_IN_PROC(p), 857 ("proc_reap: no residual thread!")); 858 uma_zfree(proc_zone, p); 859 sx_xlock(&allproc_lock); 860 nprocs--; 861 sx_xunlock(&allproc_lock); 862 } 863 864 static int 865 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id, 866 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo) 867 { 868 struct proc *q; 869 struct rusage *rup; 870 871 sx_assert(&proctree_lock, SA_XLOCKED); 872 873 q = td->td_proc; 874 PROC_LOCK(p); 875 876 switch (idtype) { 877 case P_ALL: 878 break; 879 case P_PID: 880 if (p->p_pid != (pid_t)id) { 881 PROC_UNLOCK(p); 882 return (0); 883 } 884 break; 885 case P_PGID: 886 if (p->p_pgid != (pid_t)id) { 887 PROC_UNLOCK(p); 888 return (0); 889 } 890 break; 891 case P_SID: 892 if (p->p_session->s_sid != (pid_t)id) { 893 PROC_UNLOCK(p); 894 return (0); 895 } 896 break; 897 case P_UID: 898 if (p->p_ucred->cr_uid != (uid_t)id) { 899 PROC_UNLOCK(p); 900 return (0); 901 } 902 break; 903 case P_GID: 904 if (p->p_ucred->cr_gid != (gid_t)id) { 905 PROC_UNLOCK(p); 906 return (0); 907 } 908 break; 909 case P_JAILID: 910 if (p->p_ucred->cr_prison->pr_id != (int)id) { 911 PROC_UNLOCK(p); 912 return (0); 913 } 914 break; 915 /* 916 * It seems that the thread structures get zeroed out 917 * at process exit. This makes it impossible to 918 * support P_SETID, P_CID or P_CPUID. 919 */ 920 default: 921 PROC_UNLOCK(p); 922 return (0); 923 } 924 925 if (p_canwait(td, p)) { 926 PROC_UNLOCK(p); 927 return (0); 928 } 929 930 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) { 931 PROC_UNLOCK(p); 932 return (0); 933 } 934 935 /* 936 * This special case handles a kthread spawned by linux_clone 937 * (see linux_misc.c). The linux_wait4 and linux_waitpid 938 * functions need to be able to distinguish between waiting 939 * on a process and waiting on a thread. It is a thread if 940 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 941 * signifies we want to wait for threads and not processes. 942 */ 943 if ((p->p_sigparent != SIGCHLD) ^ 944 ((options & WLINUXCLONE) != 0)) { 945 PROC_UNLOCK(p); 946 return (0); 947 } 948 949 PROC_SLOCK(p); 950 951 if (siginfo != NULL) { 952 bzero(siginfo, sizeof(*siginfo)); 953 siginfo->si_errno = 0; 954 955 /* 956 * SUSv4 requires that the si_signo value is always 957 * SIGCHLD. Obey it despite the rfork(2) interface 958 * allows to request other signal for child exit 959 * notification. 960 */ 961 siginfo->si_signo = SIGCHLD; 962 963 /* 964 * This is still a rough estimate. We will fix the 965 * cases TRAPPED, STOPPED, and CONTINUED later. 966 */ 967 if (WCOREDUMP(p->p_xstat)) { 968 siginfo->si_code = CLD_DUMPED; 969 siginfo->si_status = WTERMSIG(p->p_xstat); 970 } else if (WIFSIGNALED(p->p_xstat)) { 971 siginfo->si_code = CLD_KILLED; 972 siginfo->si_status = WTERMSIG(p->p_xstat); 973 } else { 974 siginfo->si_code = CLD_EXITED; 975 siginfo->si_status = WEXITSTATUS(p->p_xstat); 976 } 977 978 siginfo->si_pid = p->p_pid; 979 siginfo->si_uid = p->p_ucred->cr_uid; 980 981 /* 982 * The si_addr field would be useful additional 983 * detail, but apparently the PC value may be lost 984 * when we reach this point. bzero() above sets 985 * siginfo->si_addr to NULL. 986 */ 987 } 988 989 /* 990 * There should be no reason to limit resources usage info to 991 * exited processes only. A snapshot about any resources used 992 * by a stopped process may be exactly what is needed. 993 */ 994 if (wrusage != NULL) { 995 rup = &wrusage->wru_self; 996 *rup = p->p_ru; 997 calcru(p, &rup->ru_utime, &rup->ru_stime); 998 999 rup = &wrusage->wru_children; 1000 *rup = p->p_stats->p_cru; 1001 calccru(p, &rup->ru_utime, &rup->ru_stime); 1002 } 1003 1004 if (p->p_state == PRS_ZOMBIE) { 1005 proc_reap(td, p, status, options); 1006 return (-1); 1007 } 1008 PROC_SUNLOCK(p); 1009 PROC_UNLOCK(p); 1010 return (1); 1011 } 1012 1013 int 1014 kern_wait(struct thread *td, pid_t pid, int *status, int options, 1015 struct rusage *rusage) 1016 { 1017 struct __wrusage wru, *wrup; 1018 idtype_t idtype; 1019 id_t id; 1020 int ret; 1021 1022 /* 1023 * Translate the special pid values into the (idtype, pid) 1024 * pair for kern_wait6. The WAIT_MYPGRP case is handled by 1025 * kern_wait6() on its own. 1026 */ 1027 if (pid == WAIT_ANY) { 1028 idtype = P_ALL; 1029 id = 0; 1030 } else if (pid < 0) { 1031 idtype = P_PGID; 1032 id = (id_t)-pid; 1033 } else { 1034 idtype = P_PID; 1035 id = (id_t)pid; 1036 } 1037 1038 if (rusage != NULL) 1039 wrup = &wru; 1040 else 1041 wrup = NULL; 1042 1043 /* 1044 * For backward compatibility we implicitly add flags WEXITED 1045 * and WTRAPPED here. 1046 */ 1047 options |= WEXITED | WTRAPPED; 1048 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL); 1049 if (rusage != NULL) 1050 *rusage = wru.wru_self; 1051 return (ret); 1052 } 1053 1054 int 1055 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status, 1056 int options, struct __wrusage *wrusage, siginfo_t *siginfo) 1057 { 1058 struct proc *p, *q; 1059 int error, nfound, ret; 1060 1061 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */ 1062 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */ 1063 AUDIT_ARG_VALUE(options); 1064 1065 q = td->td_proc; 1066 1067 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { 1068 PROC_LOCK(q); 1069 id = (id_t)q->p_pgid; 1070 PROC_UNLOCK(q); 1071 idtype = P_PGID; 1072 } 1073 1074 /* If we don't know the option, just return. */ 1075 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT | 1076 WEXITED | WTRAPPED | WLINUXCLONE)) != 0) 1077 return (EINVAL); 1078 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) { 1079 /* 1080 * We will be unable to find any matching processes, 1081 * because there are no known events to look for. 1082 * Prefer to return error instead of blocking 1083 * indefinitely. 1084 */ 1085 return (EINVAL); 1086 } 1087 1088 loop: 1089 if (q->p_flag & P_STATCHILD) { 1090 PROC_LOCK(q); 1091 q->p_flag &= ~P_STATCHILD; 1092 PROC_UNLOCK(q); 1093 } 1094 nfound = 0; 1095 sx_xlock(&proctree_lock); 1096 LIST_FOREACH(p, &q->p_children, p_sibling) { 1097 ret = proc_to_reap(td, p, idtype, id, status, options, 1098 wrusage, siginfo); 1099 if (ret == 0) 1100 continue; 1101 else if (ret == 1) 1102 nfound++; 1103 else 1104 return (0); 1105 1106 PROC_LOCK(p); 1107 PROC_SLOCK(p); 1108 1109 if ((options & WTRAPPED) != 0 && 1110 (p->p_flag & P_TRACED) != 0 && 1111 (p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) != 0 && 1112 (p->p_suspcount == p->p_numthreads) && 1113 ((p->p_flag & P_WAITED) == 0)) { 1114 PROC_SUNLOCK(p); 1115 if ((options & WNOWAIT) == 0) 1116 p->p_flag |= P_WAITED; 1117 sx_xunlock(&proctree_lock); 1118 td->td_retval[0] = p->p_pid; 1119 1120 if (status != NULL) 1121 *status = W_STOPCODE(p->p_xstat); 1122 if (siginfo != NULL) { 1123 siginfo->si_status = p->p_xstat; 1124 siginfo->si_code = CLD_TRAPPED; 1125 } 1126 if ((options & WNOWAIT) == 0) { 1127 PROC_LOCK(q); 1128 sigqueue_take(p->p_ksi); 1129 PROC_UNLOCK(q); 1130 } 1131 1132 PROC_UNLOCK(p); 1133 return (0); 1134 } 1135 if ((options & WUNTRACED) != 0 && 1136 (p->p_flag & P_STOPPED_SIG) != 0 && 1137 (p->p_suspcount == p->p_numthreads) && 1138 ((p->p_flag & P_WAITED) == 0)) { 1139 PROC_SUNLOCK(p); 1140 if ((options & WNOWAIT) == 0) 1141 p->p_flag |= P_WAITED; 1142 sx_xunlock(&proctree_lock); 1143 td->td_retval[0] = p->p_pid; 1144 1145 if (status != NULL) 1146 *status = W_STOPCODE(p->p_xstat); 1147 if (siginfo != NULL) { 1148 siginfo->si_status = p->p_xstat; 1149 siginfo->si_code = CLD_STOPPED; 1150 } 1151 if ((options & WNOWAIT) == 0) { 1152 PROC_LOCK(q); 1153 sigqueue_take(p->p_ksi); 1154 PROC_UNLOCK(q); 1155 } 1156 1157 PROC_UNLOCK(p); 1158 return (0); 1159 } 1160 PROC_SUNLOCK(p); 1161 if ((options & WCONTINUED) != 0 && 1162 (p->p_flag & P_CONTINUED) != 0) { 1163 sx_xunlock(&proctree_lock); 1164 td->td_retval[0] = p->p_pid; 1165 if ((options & WNOWAIT) == 0) { 1166 p->p_flag &= ~P_CONTINUED; 1167 PROC_LOCK(q); 1168 sigqueue_take(p->p_ksi); 1169 PROC_UNLOCK(q); 1170 } 1171 PROC_UNLOCK(p); 1172 1173 if (status != NULL) 1174 *status = SIGCONT; 1175 if (siginfo != NULL) { 1176 siginfo->si_status = SIGCONT; 1177 siginfo->si_code = CLD_CONTINUED; 1178 } 1179 return (0); 1180 } 1181 PROC_UNLOCK(p); 1182 } 1183 1184 /* 1185 * Look in the orphans list too, to allow the parent to 1186 * collect it's child exit status even if child is being 1187 * debugged. 1188 * 1189 * Debugger detaches from the parent upon successful 1190 * switch-over from parent to child. At this point due to 1191 * re-parenting the parent loses the child to debugger and a 1192 * wait4(2) call would report that it has no children to wait 1193 * for. By maintaining a list of orphans we allow the parent 1194 * to successfully wait until the child becomes a zombie. 1195 */ 1196 LIST_FOREACH(p, &q->p_orphans, p_orphan) { 1197 ret = proc_to_reap(td, p, idtype, id, status, options, 1198 wrusage, siginfo); 1199 if (ret == 0) 1200 continue; 1201 else if (ret == 1) 1202 nfound++; 1203 else 1204 return (0); 1205 } 1206 if (nfound == 0) { 1207 sx_xunlock(&proctree_lock); 1208 return (ECHILD); 1209 } 1210 if (options & WNOHANG) { 1211 sx_xunlock(&proctree_lock); 1212 td->td_retval[0] = 0; 1213 return (0); 1214 } 1215 PROC_LOCK(q); 1216 sx_xunlock(&proctree_lock); 1217 if (q->p_flag & P_STATCHILD) { 1218 q->p_flag &= ~P_STATCHILD; 1219 error = 0; 1220 } else 1221 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 1222 PROC_UNLOCK(q); 1223 if (error) 1224 return (error); 1225 goto loop; 1226 } 1227 1228 /* 1229 * Make process 'parent' the new parent of process 'child'. 1230 * Must be called with an exclusive hold of proctree lock. 1231 */ 1232 void 1233 proc_reparent(struct proc *child, struct proc *parent) 1234 { 1235 1236 sx_assert(&proctree_lock, SX_XLOCKED); 1237 PROC_LOCK_ASSERT(child, MA_OWNED); 1238 if (child->p_pptr == parent) 1239 return; 1240 1241 PROC_LOCK(child->p_pptr); 1242 sigqueue_take(child->p_ksi); 1243 PROC_UNLOCK(child->p_pptr); 1244 LIST_REMOVE(child, p_sibling); 1245 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1246 1247 clear_orphan(child); 1248 if (child->p_flag & P_TRACED) { 1249 LIST_INSERT_HEAD(&child->p_pptr->p_orphans, child, p_orphan); 1250 child->p_flag |= P_ORPHAN; 1251 } 1252 1253 child->p_pptr = parent; 1254 } 1255