1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_compat.h" 41 #include "opt_kdtrace.h" 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/sysproto.h> 47 #include <sys/eventhandler.h> 48 #include <sys/kernel.h> 49 #include <sys/malloc.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/proc.h> 53 #include <sys/pioctl.h> 54 #include <sys/jail.h> 55 #include <sys/tty.h> 56 #include <sys/wait.h> 57 #include <sys/vmmeter.h> 58 #include <sys/vnode.h> 59 #include <sys/resourcevar.h> 60 #include <sys/sbuf.h> 61 #include <sys/signalvar.h> 62 #include <sys/sched.h> 63 #include <sys/sx.h> 64 #include <sys/syscallsubr.h> 65 #include <sys/syslog.h> 66 #include <sys/ptrace.h> 67 #include <sys/acct.h> /* for acct_process() function prototype */ 68 #include <sys/filedesc.h> 69 #include <sys/sdt.h> 70 #include <sys/shm.h> 71 #include <sys/sem.h> 72 #ifdef KTRACE 73 #include <sys/ktrace.h> 74 #endif 75 76 #include <security/audit/audit.h> 77 #include <security/mac/mac_framework.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_extern.h> 81 #include <vm/vm_param.h> 82 #include <vm/pmap.h> 83 #include <vm/vm_map.h> 84 #include <vm/vm_page.h> 85 #include <vm/uma.h> 86 87 #ifdef KDTRACE_HOOKS 88 #include <sys/dtrace_bsd.h> 89 dtrace_execexit_func_t dtrace_fasttrap_exit; 90 #endif 91 92 SDT_PROVIDER_DECLARE(proc); 93 SDT_PROBE_DEFINE(proc, kernel, , exit, exit); 94 SDT_PROBE_ARGTYPE(proc, kernel, , exit, 0, "int"); 95 96 /* Required to be non-static for SysVR4 emulator */ 97 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 98 99 /* Hook for NFS teardown procedure. */ 100 void (*nlminfo_release_p)(struct proc *p); 101 102 /* 103 * exit -- death of process. 104 */ 105 void 106 sys_exit(struct thread *td, struct sys_exit_args *uap) 107 { 108 109 exit1(td, W_EXITCODE(uap->rval, 0)); 110 /* NOTREACHED */ 111 } 112 113 /* 114 * Exit: deallocate address space and other resources, change proc state to 115 * zombie, and unlink proc from allproc and parent's lists. Save exit status 116 * and rusage for wait(). Check for child processes and orphan them. 117 */ 118 void 119 exit1(struct thread *td, int rv) 120 { 121 struct proc *p, *nq, *q; 122 struct vnode *vtmp; 123 struct vnode *ttyvp = NULL; 124 #ifdef KTRACE 125 struct vnode *tracevp; 126 struct ucred *tracecred; 127 #endif 128 struct plimit *plim; 129 int locked; 130 131 mtx_assert(&Giant, MA_NOTOWNED); 132 133 p = td->td_proc; 134 /* 135 * XXX in case we're rebooting we just let init die in order to 136 * work around an unsolved stack overflow seen very late during 137 * shutdown on sparc64 when the gmirror worker process exists. 138 */ 139 if (p == initproc && rebooting == 0) { 140 printf("init died (signal %d, exit %d)\n", 141 WTERMSIG(rv), WEXITSTATUS(rv)); 142 panic("Going nowhere without my init!"); 143 } 144 145 /* 146 * MUST abort all other threads before proceeding past here. 147 */ 148 PROC_LOCK(p); 149 while (p->p_flag & P_HADTHREADS) { 150 /* 151 * First check if some other thread got here before us.. 152 * if so, act apropriatly, (exit or suspend); 153 */ 154 thread_suspend_check(0); 155 156 /* 157 * Kill off the other threads. This requires 158 * some co-operation from other parts of the kernel 159 * so it may not be instantaneous. With this state set 160 * any thread entering the kernel from userspace will 161 * thread_exit() in trap(). Any thread attempting to 162 * sleep will return immediately with EINTR or EWOULDBLOCK 163 * which will hopefully force them to back out to userland 164 * freeing resources as they go. Any thread attempting 165 * to return to userland will thread_exit() from userret(). 166 * thread_exit() will unsuspend us when the last of the 167 * other threads exits. 168 * If there is already a thread singler after resumption, 169 * calling thread_single will fail; in that case, we just 170 * re-check all suspension request, the thread should 171 * either be suspended there or exit. 172 */ 173 if (! thread_single(SINGLE_EXIT)) 174 break; 175 176 /* 177 * All other activity in this process is now stopped. 178 * Threading support has been turned off. 179 */ 180 } 181 KASSERT(p->p_numthreads == 1, 182 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 183 /* 184 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 185 * on our vmspace, so we should block below until they have 186 * released their reference to us. Note that if they have 187 * requested S_EXIT stops we will block here until they ack 188 * via PIOCCONT. 189 */ 190 _STOPEVENT(p, S_EXIT, rv); 191 192 /* 193 * Note that we are exiting and do another wakeup of anyone in 194 * PIOCWAIT in case they aren't listening for S_EXIT stops or 195 * decided to wait again after we told them we are exiting. 196 */ 197 p->p_flag |= P_WEXIT; 198 wakeup(&p->p_stype); 199 200 /* 201 * Wait for any processes that have a hold on our vmspace to 202 * release their reference. 203 */ 204 while (p->p_lock > 0) 205 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 206 207 PROC_UNLOCK(p); 208 /* Drain the limit callout while we don't have the proc locked */ 209 callout_drain(&p->p_limco); 210 211 #ifdef AUDIT 212 /* 213 * The Sun BSM exit token contains two components: an exit status as 214 * passed to exit(), and a return value to indicate what sort of exit 215 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 216 * what the return value is. 217 */ 218 AUDIT_ARG_EXIT(WEXITSTATUS(rv), 0); 219 AUDIT_SYSCALL_EXIT(0, td); 220 #endif 221 222 /* Are we a task leader? */ 223 if (p == p->p_leader) { 224 mtx_lock(&ppeers_lock); 225 q = p->p_peers; 226 while (q != NULL) { 227 PROC_LOCK(q); 228 psignal(q, SIGKILL); 229 PROC_UNLOCK(q); 230 q = q->p_peers; 231 } 232 while (p->p_peers != NULL) 233 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 234 mtx_unlock(&ppeers_lock); 235 } 236 237 /* 238 * Check if any loadable modules need anything done at process exit. 239 * E.g. SYSV IPC stuff 240 * XXX what if one of these generates an error? 241 */ 242 EVENTHANDLER_INVOKE(process_exit, p); 243 244 /* 245 * If parent is waiting for us to exit or exec, 246 * P_PPWAIT is set; we will wakeup the parent below. 247 */ 248 PROC_LOCK(p); 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 /* 360 * Disable tracing, then drain any pending records and release 361 * the trace file. 362 */ 363 if (p->p_traceflag != 0) { 364 PROC_LOCK(p); 365 mtx_lock(&ktrace_mtx); 366 p->p_traceflag = 0; 367 mtx_unlock(&ktrace_mtx); 368 PROC_UNLOCK(p); 369 ktrprocexit(td); 370 PROC_LOCK(p); 371 mtx_lock(&ktrace_mtx); 372 tracevp = p->p_tracevp; 373 p->p_tracevp = NULL; 374 tracecred = p->p_tracecred; 375 p->p_tracecred = NULL; 376 mtx_unlock(&ktrace_mtx); 377 PROC_UNLOCK(p); 378 if (tracevp != NULL) { 379 locked = VFS_LOCK_GIANT(tracevp->v_mount); 380 vrele(tracevp); 381 VFS_UNLOCK_GIANT(locked); 382 } 383 if (tracecred != NULL) 384 crfree(tracecred); 385 } 386 #endif 387 /* 388 * Release reference to text vnode 389 */ 390 if ((vtmp = p->p_textvp) != NULL) { 391 p->p_textvp = NULL; 392 locked = VFS_LOCK_GIANT(vtmp->v_mount); 393 vrele(vtmp); 394 VFS_UNLOCK_GIANT(locked); 395 } 396 397 /* 398 * Release our limits structure. 399 */ 400 PROC_LOCK(p); 401 plim = p->p_limit; 402 p->p_limit = NULL; 403 PROC_UNLOCK(p); 404 lim_free(plim); 405 406 tidhash_remove(td); 407 408 /* 409 * Remove proc from allproc queue and pidhash chain. 410 * Place onto zombproc. Unlink from parent's child list. 411 */ 412 sx_xlock(&allproc_lock); 413 LIST_REMOVE(p, p_list); 414 LIST_INSERT_HEAD(&zombproc, p, p_list); 415 LIST_REMOVE(p, p_hash); 416 sx_xunlock(&allproc_lock); 417 418 /* 419 * Call machine-dependent code to release any 420 * machine-dependent resources other than the address space. 421 * The address space is released by "vmspace_exitfree(p)" in 422 * vm_waitproc(). 423 */ 424 cpu_exit(td); 425 426 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 427 428 /* 429 * Reparent all of our children to init. 430 */ 431 sx_xlock(&proctree_lock); 432 q = LIST_FIRST(&p->p_children); 433 if (q != NULL) /* only need this if any child is S_ZOMB */ 434 wakeup(initproc); 435 for (; q != NULL; q = nq) { 436 nq = LIST_NEXT(q, p_sibling); 437 PROC_LOCK(q); 438 proc_reparent(q, initproc); 439 q->p_sigparent = SIGCHLD; 440 /* 441 * Traced processes are killed 442 * since their existence means someone is screwing up. 443 */ 444 if (q->p_flag & P_TRACED) { 445 struct thread *temp; 446 447 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 448 FOREACH_THREAD_IN_PROC(q, temp) 449 temp->td_dbgflags &= ~TDB_SUSPEND; 450 psignal(q, SIGKILL); 451 } 452 PROC_UNLOCK(q); 453 } 454 455 /* Save exit status. */ 456 PROC_LOCK(p); 457 p->p_xstat = rv; 458 p->p_xthread = td; 459 460 /* Tell the prison that we are gone. */ 461 prison_proc_free(p->p_ucred->cr_prison); 462 463 #ifdef KDTRACE_HOOKS 464 /* 465 * Tell the DTrace fasttrap provider about the exit if it 466 * has declared an interest. 467 */ 468 if (dtrace_fasttrap_exit) 469 dtrace_fasttrap_exit(p); 470 #endif 471 472 /* 473 * Notify interested parties of our demise. 474 */ 475 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 476 477 #ifdef KDTRACE_HOOKS 478 int reason = CLD_EXITED; 479 if (WCOREDUMP(rv)) 480 reason = CLD_DUMPED; 481 else if (WIFSIGNALED(rv)) 482 reason = CLD_KILLED; 483 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 484 #endif 485 486 /* 487 * Just delete all entries in the p_klist. At this point we won't 488 * report any more events, and there are nasty race conditions that 489 * can beat us if we don't. 490 */ 491 knlist_clear(&p->p_klist, 1); 492 493 /* 494 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 495 * flag set, or if the handler is set to SIG_IGN, notify process 496 * 1 instead (and hope it will handle this situation). 497 */ 498 PROC_LOCK(p->p_pptr); 499 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 500 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 501 struct proc *pp; 502 503 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 504 pp = p->p_pptr; 505 PROC_UNLOCK(pp); 506 proc_reparent(p, initproc); 507 p->p_sigparent = SIGCHLD; 508 PROC_LOCK(p->p_pptr); 509 510 /* 511 * Notify parent, so in case he was wait(2)ing or 512 * executing waitpid(2) with our pid, he will 513 * continue. 514 */ 515 wakeup(pp); 516 } else 517 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 518 519 if (p->p_pptr == initproc) 520 psignal(p->p_pptr, SIGCHLD); 521 else if (p->p_sigparent != 0) { 522 if (p->p_sigparent == SIGCHLD) 523 childproc_exited(p); 524 else /* LINUX thread */ 525 psignal(p->p_pptr, p->p_sigparent); 526 } 527 sx_xunlock(&proctree_lock); 528 529 /* 530 * The state PRS_ZOMBIE prevents other proesses from sending 531 * signal to the process, to avoid memory leak, we free memory 532 * for signal queue at the time when the state is set. 533 */ 534 sigqueue_flush(&p->p_sigqueue); 535 sigqueue_flush(&td->td_sigqueue); 536 537 /* 538 * We have to wait until after acquiring all locks before 539 * changing p_state. We need to avoid all possible context 540 * switches (including ones from blocking on a mutex) while 541 * marked as a zombie. We also have to set the zombie state 542 * before we release the parent process' proc lock to avoid 543 * a lost wakeup. So, we first call wakeup, then we grab the 544 * sched lock, update the state, and release the parent process' 545 * proc lock. 546 */ 547 wakeup(p->p_pptr); 548 cv_broadcast(&p->p_pwait); 549 sched_exit(p->p_pptr, td); 550 PROC_SLOCK(p); 551 p->p_state = PRS_ZOMBIE; 552 PROC_UNLOCK(p->p_pptr); 553 554 /* 555 * Hopefully no one will try to deliver a signal to the process this 556 * late in the game. 557 */ 558 knlist_destroy(&p->p_klist); 559 560 /* 561 * Save our children's rusage information in our exit rusage. 562 */ 563 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 564 565 /* 566 * Make sure the scheduler takes this thread out of its tables etc. 567 * This will also release this thread's reference to the ucred. 568 * Other thread parts to release include pcb bits and such. 569 */ 570 thread_exit(); 571 } 572 573 574 #ifndef _SYS_SYSPROTO_H_ 575 struct abort2_args { 576 char *why; 577 int nargs; 578 void **args; 579 }; 580 #endif 581 582 int 583 abort2(struct thread *td, struct abort2_args *uap) 584 { 585 struct proc *p = td->td_proc; 586 struct sbuf *sb; 587 void *uargs[16]; 588 int error, i, sig; 589 590 /* 591 * Do it right now so we can log either proper call of abort2(), or 592 * note, that invalid argument was passed. 512 is big enough to 593 * handle 16 arguments' descriptions with additional comments. 594 */ 595 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 596 sbuf_clear(sb); 597 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 598 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 599 /* 600 * Since we can't return from abort2(), send SIGKILL in cases, where 601 * abort2() was called improperly 602 */ 603 sig = SIGKILL; 604 /* Prevent from DoSes from user-space. */ 605 if (uap->nargs < 0 || uap->nargs > 16) 606 goto out; 607 if (uap->nargs > 0) { 608 if (uap->args == NULL) 609 goto out; 610 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 611 if (error != 0) 612 goto out; 613 } 614 /* 615 * Limit size of 'reason' string to 128. Will fit even when 616 * maximal number of arguments was chosen to be logged. 617 */ 618 if (uap->why != NULL) { 619 error = sbuf_copyin(sb, uap->why, 128); 620 if (error < 0) 621 goto out; 622 } else { 623 sbuf_printf(sb, "(null)"); 624 } 625 if (uap->nargs > 0) { 626 sbuf_printf(sb, "("); 627 for (i = 0;i < uap->nargs; i++) 628 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 629 sbuf_printf(sb, ")"); 630 } 631 /* 632 * Final stage: arguments were proper, string has been 633 * successfully copied from userspace, and copying pointers 634 * from user-space succeed. 635 */ 636 sig = SIGABRT; 637 out: 638 if (sig == SIGKILL) { 639 sbuf_trim(sb); 640 sbuf_printf(sb, " (Reason text inaccessible)"); 641 } 642 sbuf_cat(sb, "\n"); 643 sbuf_finish(sb); 644 log(LOG_INFO, "%s", sbuf_data(sb)); 645 sbuf_delete(sb); 646 exit1(td, W_EXITCODE(0, sig)); 647 return (0); 648 } 649 650 651 #ifdef COMPAT_43 652 /* 653 * The dirty work is handled by kern_wait(). 654 */ 655 int 656 owait(struct thread *td, struct owait_args *uap __unused) 657 { 658 int error, status; 659 660 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 661 if (error == 0) 662 td->td_retval[1] = status; 663 return (error); 664 } 665 #endif /* COMPAT_43 */ 666 667 /* 668 * The dirty work is handled by kern_wait(). 669 */ 670 int 671 wait4(struct thread *td, struct wait_args *uap) 672 { 673 struct rusage ru, *rup; 674 int error, status; 675 676 if (uap->rusage != NULL) 677 rup = &ru; 678 else 679 rup = NULL; 680 error = kern_wait(td, uap->pid, &status, uap->options, rup); 681 if (uap->status != NULL && error == 0) 682 error = copyout(&status, uap->status, sizeof(status)); 683 if (uap->rusage != NULL && error == 0) 684 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 685 return (error); 686 } 687 688 /* 689 * Reap the remains of a zombie process and optionally return status and 690 * rusage. Asserts and will release both the proctree_lock and the process 691 * lock as part of its work. 692 */ 693 static void 694 proc_reap(struct thread *td, struct proc *p, int *status, int options, 695 struct rusage *rusage) 696 { 697 struct proc *q, *t; 698 699 sx_assert(&proctree_lock, SA_XLOCKED); 700 PROC_LOCK_ASSERT(p, MA_OWNED); 701 PROC_SLOCK_ASSERT(p, MA_OWNED); 702 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 703 704 q = td->td_proc; 705 if (rusage) { 706 *rusage = p->p_ru; 707 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 708 } 709 PROC_SUNLOCK(p); 710 td->td_retval[0] = p->p_pid; 711 if (status) 712 *status = p->p_xstat; /* convert to int */ 713 if (options & WNOWAIT) { 714 /* 715 * Only poll, returning the status. Caller does not wish to 716 * release the proc struct just yet. 717 */ 718 PROC_UNLOCK(p); 719 sx_xunlock(&proctree_lock); 720 return; 721 } 722 723 PROC_LOCK(q); 724 sigqueue_take(p->p_ksi); 725 PROC_UNLOCK(q); 726 PROC_UNLOCK(p); 727 728 /* 729 * If we got the child via a ptrace 'attach', we need to give it back 730 * to the old parent. 731 */ 732 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 733 PROC_LOCK(p); 734 p->p_oppid = 0; 735 proc_reparent(p, t); 736 PROC_UNLOCK(p); 737 pksignal(t, SIGCHLD, p->p_ksi); 738 wakeup(t); 739 cv_broadcast(&p->p_pwait); 740 PROC_UNLOCK(t); 741 sx_xunlock(&proctree_lock); 742 return; 743 } 744 745 /* 746 * Remove other references to this process to ensure we have an 747 * exclusive reference. 748 */ 749 sx_xlock(&allproc_lock); 750 LIST_REMOVE(p, p_list); /* off zombproc */ 751 sx_xunlock(&allproc_lock); 752 LIST_REMOVE(p, p_sibling); 753 leavepgrp(p); 754 sx_xunlock(&proctree_lock); 755 756 /* 757 * As a side effect of this lock, we know that all other writes to 758 * this proc are visible now, so no more locking is needed for p. 759 */ 760 PROC_LOCK(p); 761 p->p_xstat = 0; /* XXX: why? */ 762 PROC_UNLOCK(p); 763 PROC_LOCK(q); 764 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 765 PROC_UNLOCK(q); 766 767 /* 768 * Decrement the count of procs running with this uid. 769 */ 770 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 771 772 /* 773 * Free credentials, arguments, and sigacts. 774 */ 775 crfree(p->p_ucred); 776 p->p_ucred = NULL; 777 pargs_drop(p->p_args); 778 p->p_args = NULL; 779 sigacts_free(p->p_sigacts); 780 p->p_sigacts = NULL; 781 782 /* 783 * Do any thread-system specific cleanups. 784 */ 785 thread_wait(p); 786 787 /* 788 * Give vm and machine-dependent layer a chance to free anything that 789 * cpu_exit couldn't release while still running in process context. 790 */ 791 vm_waitproc(p); 792 #ifdef MAC 793 mac_proc_destroy(p); 794 #endif 795 KASSERT(FIRST_THREAD_IN_PROC(p), 796 ("proc_reap: no residual thread!")); 797 uma_zfree(proc_zone, p); 798 sx_xlock(&allproc_lock); 799 nprocs--; 800 sx_xunlock(&allproc_lock); 801 } 802 803 int 804 kern_wait(struct thread *td, pid_t pid, int *status, int options, 805 struct rusage *rusage) 806 { 807 struct proc *p, *q; 808 int error, nfound; 809 810 AUDIT_ARG_PID(pid); 811 AUDIT_ARG_VALUE(options); 812 813 q = td->td_proc; 814 if (pid == 0) { 815 PROC_LOCK(q); 816 pid = -q->p_pgid; 817 PROC_UNLOCK(q); 818 } 819 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE)) 820 return (EINVAL); 821 loop: 822 if (q->p_flag & P_STATCHILD) { 823 PROC_LOCK(q); 824 q->p_flag &= ~P_STATCHILD; 825 PROC_UNLOCK(q); 826 } 827 nfound = 0; 828 sx_xlock(&proctree_lock); 829 LIST_FOREACH(p, &q->p_children, p_sibling) { 830 PROC_LOCK(p); 831 if (pid != WAIT_ANY && 832 p->p_pid != pid && p->p_pgid != -pid) { 833 PROC_UNLOCK(p); 834 continue; 835 } 836 if (p_canwait(td, p)) { 837 PROC_UNLOCK(p); 838 continue; 839 } 840 841 /* 842 * This special case handles a kthread spawned by linux_clone 843 * (see linux_misc.c). The linux_wait4 and linux_waitpid 844 * functions need to be able to distinguish between waiting 845 * on a process and waiting on a thread. It is a thread if 846 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 847 * signifies we want to wait for threads and not processes. 848 */ 849 if ((p->p_sigparent != SIGCHLD) ^ 850 ((options & WLINUXCLONE) != 0)) { 851 PROC_UNLOCK(p); 852 continue; 853 } 854 855 nfound++; 856 PROC_SLOCK(p); 857 if (p->p_state == PRS_ZOMBIE) { 858 proc_reap(td, p, status, options, rusage); 859 return (0); 860 } 861 if ((p->p_flag & P_STOPPED_SIG) && 862 (p->p_suspcount == p->p_numthreads) && 863 (p->p_flag & P_WAITED) == 0 && 864 (p->p_flag & P_TRACED || options & WUNTRACED)) { 865 PROC_SUNLOCK(p); 866 p->p_flag |= P_WAITED; 867 sx_xunlock(&proctree_lock); 868 td->td_retval[0] = p->p_pid; 869 if (status) 870 *status = W_STOPCODE(p->p_xstat); 871 872 PROC_LOCK(q); 873 sigqueue_take(p->p_ksi); 874 PROC_UNLOCK(q); 875 PROC_UNLOCK(p); 876 877 return (0); 878 } 879 PROC_SUNLOCK(p); 880 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 881 sx_xunlock(&proctree_lock); 882 td->td_retval[0] = p->p_pid; 883 p->p_flag &= ~P_CONTINUED; 884 885 PROC_LOCK(q); 886 sigqueue_take(p->p_ksi); 887 PROC_UNLOCK(q); 888 PROC_UNLOCK(p); 889 890 if (status) 891 *status = SIGCONT; 892 return (0); 893 } 894 PROC_UNLOCK(p); 895 } 896 if (nfound == 0) { 897 sx_xunlock(&proctree_lock); 898 return (ECHILD); 899 } 900 if (options & WNOHANG) { 901 sx_xunlock(&proctree_lock); 902 td->td_retval[0] = 0; 903 return (0); 904 } 905 PROC_LOCK(q); 906 sx_xunlock(&proctree_lock); 907 if (q->p_flag & P_STATCHILD) { 908 q->p_flag &= ~P_STATCHILD; 909 error = 0; 910 } else 911 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 912 PROC_UNLOCK(q); 913 if (error) 914 return (error); 915 goto loop; 916 } 917 918 /* 919 * Make process 'parent' the new parent of process 'child'. 920 * Must be called with an exclusive hold of proctree lock. 921 */ 922 void 923 proc_reparent(struct proc *child, struct proc *parent) 924 { 925 926 sx_assert(&proctree_lock, SX_XLOCKED); 927 PROC_LOCK_ASSERT(child, MA_OWNED); 928 if (child->p_pptr == parent) 929 return; 930 931 PROC_LOCK(child->p_pptr); 932 sigqueue_take(child->p_ksi); 933 PROC_UNLOCK(child->p_pptr); 934 LIST_REMOVE(child, p_sibling); 935 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 936 child->p_pptr = parent; 937 } 938