1 /* $NetBSD: kern_exit.c,v 1.237 2012/02/19 21:06:50 rmind Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 1999, 2006, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center, and by Andrew Doran. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1982, 1986, 1989, 1991, 1993 35 * The Regents of the University of California. All rights reserved. 36 * (c) UNIX System Laboratories, Inc. 37 * All or some portions of this file are derived from material licensed 38 * to the University of California by American Telephone and Telegraph 39 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 40 * the permission of UNIX System Laboratories, Inc. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)kern_exit.c 8.10 (Berkeley) 2/23/95 67 */ 68 69 #include <sys/cdefs.h> 70 __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.237 2012/02/19 21:06:50 rmind Exp $"); 71 72 #include "opt_ktrace.h" 73 #include "opt_perfctrs.h" 74 #include "opt_sysv.h" 75 76 #include <sys/param.h> 77 #include <sys/systm.h> 78 #include <sys/ioctl.h> 79 #include <sys/tty.h> 80 #include <sys/time.h> 81 #include <sys/resource.h> 82 #include <sys/kernel.h> 83 #include <sys/proc.h> 84 #include <sys/buf.h> 85 #include <sys/wait.h> 86 #include <sys/file.h> 87 #include <sys/vnode.h> 88 #include <sys/syslog.h> 89 #include <sys/pool.h> 90 #include <sys/uidinfo.h> 91 #if defined(PERFCTRS) 92 #include <sys/pmc.h> 93 #endif 94 #include <sys/ptrace.h> 95 #include <sys/acct.h> 96 #include <sys/filedesc.h> 97 #include <sys/ras.h> 98 #include <sys/signalvar.h> 99 #include <sys/sched.h> 100 #include <sys/mount.h> 101 #include <sys/syscallargs.h> 102 #include <sys/kauth.h> 103 #include <sys/sleepq.h> 104 #include <sys/lockdebug.h> 105 #include <sys/ktrace.h> 106 #include <sys/cpu.h> 107 #include <sys/lwpctl.h> 108 #include <sys/atomic.h> 109 #include <sys/sdt.h> 110 111 #include <uvm/uvm_extern.h> 112 113 #ifdef DEBUG_EXIT 114 int debug_exit = 0; 115 #define DPRINTF(x) if (debug_exit) printf x 116 #else 117 #define DPRINTF(x) 118 #endif 119 120 static int find_stopped_child(struct proc *, pid_t, int, struct proc **, int *); 121 static void proc_free(struct proc *, struct rusage *); 122 123 /* 124 * DTrace SDT provider definitions 125 */ 126 SDT_PROBE_DEFINE(proc,,,exit, 127 "int", NULL, /* reason */ 128 NULL, NULL, NULL, NULL, 129 NULL, NULL, NULL, NULL); 130 /* 131 * Fill in the appropriate signal information, and signal the parent. 132 */ 133 /* XXX noclone works around a gcc 4.5 bug on arm */ 134 static void __noclone 135 exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi) 136 { 137 138 KSI_INIT(ksi); 139 if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) { 140 if (WIFSIGNALED(p->p_xstat)) { 141 if (WCOREDUMP(p->p_xstat)) 142 ksi->ksi_code = CLD_DUMPED; 143 else 144 ksi->ksi_code = CLD_KILLED; 145 } else { 146 ksi->ksi_code = CLD_EXITED; 147 } 148 } 149 /* 150 * We fill those in, even for non-SIGCHLD. 151 * It's safe to access p->p_cred unlocked here. 152 */ 153 ksi->ksi_pid = p->p_pid; 154 ksi->ksi_uid = kauth_cred_geteuid(p->p_cred); 155 ksi->ksi_status = p->p_xstat; 156 /* XXX: is this still valid? */ 157 ksi->ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; 158 ksi->ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; 159 } 160 161 /* 162 * exit -- 163 * Death of process. 164 */ 165 int 166 sys_exit(struct lwp *l, const struct sys_exit_args *uap, register_t *retval) 167 { 168 /* { 169 syscallarg(int) rval; 170 } */ 171 struct proc *p = l->l_proc; 172 173 /* Don't call exit1() multiple times in the same process. */ 174 mutex_enter(p->p_lock); 175 if (p->p_sflag & PS_WEXIT) { 176 mutex_exit(p->p_lock); 177 lwp_exit(l); 178 } 179 180 /* exit1() will release the mutex. */ 181 exit1(l, W_EXITCODE(SCARG(uap, rval), 0)); 182 /* NOTREACHED */ 183 return (0); 184 } 185 186 /* 187 * Exit: deallocate address space and other resources, change proc state 188 * to zombie, and unlink proc from allproc and parent's lists. Save exit 189 * status and rusage for wait(). Check for child processes and orphan them. 190 * 191 * Must be called with p->p_lock held. Does not return. 192 */ 193 void 194 exit1(struct lwp *l, int rv) 195 { 196 struct proc *p, *q, *nq; 197 struct pgrp *pgrp; 198 ksiginfo_t ksi; 199 ksiginfoq_t kq; 200 int wakeinit; 201 202 p = l->l_proc; 203 204 KASSERT(mutex_owned(p->p_lock)); 205 206 if (__predict_false(p == initproc)) { 207 panic("init died (signal %d, exit %d)", 208 WTERMSIG(rv), WEXITSTATUS(rv)); 209 } 210 211 p->p_sflag |= PS_WEXIT; 212 213 /* 214 * Force all other LWPs to exit before we do. Only then can we 215 * begin to tear down the rest of the process state. 216 */ 217 if (p->p_nlwps > 1) { 218 exit_lwps(l); 219 } 220 221 ksiginfo_queue_init(&kq); 222 223 /* 224 * If we have been asked to stop on exit, do so now. 225 */ 226 if (__predict_false(p->p_sflag & PS_STOPEXIT)) { 227 KERNEL_UNLOCK_ALL(l, &l->l_biglocks); 228 sigclearall(p, &contsigmask, &kq); 229 p->p_waited = 0; 230 membar_producer(); 231 p->p_stat = SSTOP; 232 lwp_lock(l); 233 p->p_nrlwps--; 234 l->l_stat = LSSTOP; 235 lwp_unlock(l); 236 mutex_exit(p->p_lock); 237 lwp_lock(l); 238 mi_switch(l); 239 KERNEL_LOCK(l->l_biglocks, l); 240 mutex_enter(p->p_lock); 241 } 242 243 /* 244 * Bin any remaining signals and mark the process as dying so it will 245 * not be found for, e.g. signals. 246 */ 247 sigfillset(&p->p_sigctx.ps_sigignore); 248 sigclearall(p, NULL, &kq); 249 p->p_stat = SDYING; 250 mutex_exit(p->p_lock); 251 ksiginfo_queue_drain(&kq); 252 253 /* Destroy any lwpctl info. */ 254 if (p->p_lwpctl != NULL) 255 lwp_ctl_exit(); 256 257 /* 258 * Drain all remaining references that procfs, ptrace and others may 259 * have on the process. 260 */ 261 rw_enter(&p->p_reflock, RW_WRITER); 262 263 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid)); 264 265 timers_free(p, TIMERS_ALL); 266 #if defined(__HAVE_RAS) 267 ras_purgeall(); 268 #endif 269 270 /* 271 * Close open files, release open-file table and free signal 272 * actions. This may block! 273 */ 274 fd_free(); 275 cwdfree(p->p_cwdi); 276 p->p_cwdi = NULL; 277 doexithooks(p); 278 sigactsfree(p->p_sigacts); 279 280 /* 281 * Write out accounting data. 282 */ 283 (void)acct_process(l); 284 285 #ifdef KTRACE 286 /* 287 * Release trace file. 288 */ 289 if (p->p_tracep != NULL) { 290 mutex_enter(&ktrace_lock); 291 ktrderef(p); 292 mutex_exit(&ktrace_lock); 293 } 294 #endif 295 296 /* 297 * If emulation has process exit hook, call it now. 298 * Set the exit status now so that the exit hook has 299 * an opportunity to tweak it (COMPAT_LINUX requires 300 * this for thread group emulation) 301 */ 302 p->p_xstat = rv; 303 if (p->p_emul->e_proc_exit) 304 (*p->p_emul->e_proc_exit)(p); 305 306 /* 307 * Free the VM resources we're still holding on to. 308 * We must do this from a valid thread because doing 309 * so may block. This frees vmspace, which we don't 310 * need anymore. The only remaining lwp is the one 311 * we run at this moment, nothing runs in userland 312 * anymore. 313 */ 314 uvm_proc_exit(p); 315 316 /* 317 * Stop profiling. 318 */ 319 if (__predict_false((p->p_stflag & PST_PROFIL) != 0)) { 320 mutex_spin_enter(&p->p_stmutex); 321 stopprofclock(p); 322 mutex_spin_exit(&p->p_stmutex); 323 } 324 325 /* 326 * If parent is waiting for us to exit or exec, PL_PPWAIT is set; we 327 * wake up the parent early to avoid deadlock. We can do this once 328 * the VM resources are released. 329 */ 330 mutex_enter(proc_lock); 331 if (p->p_lflag & PL_PPWAIT) { 332 l->l_lwpctl = NULL; /* was on loan from blocked parent */ 333 p->p_lflag &= ~PL_PPWAIT; 334 cv_broadcast(&p->p_pptr->p_waitcv); 335 } 336 337 if (SESS_LEADER(p)) { 338 struct vnode *vprele = NULL, *vprevoke = NULL; 339 struct session *sp = p->p_session; 340 struct tty *tp; 341 342 if (sp->s_ttyvp) { 343 /* 344 * Controlling process. 345 * Signal foreground pgrp, 346 * drain controlling terminal 347 * and revoke access to controlling terminal. 348 */ 349 tp = sp->s_ttyp; 350 mutex_spin_enter(&tty_lock); 351 if (tp->t_session == sp) { 352 /* we can't guarantee the revoke will do this */ 353 pgrp = tp->t_pgrp; 354 tp->t_pgrp = NULL; 355 tp->t_session = NULL; 356 mutex_spin_exit(&tty_lock); 357 if (pgrp != NULL) { 358 pgsignal(pgrp, SIGHUP, 1); 359 } 360 mutex_exit(proc_lock); 361 (void) ttywait(tp); 362 mutex_enter(proc_lock); 363 364 /* The tty could have been revoked. */ 365 vprevoke = sp->s_ttyvp; 366 } else 367 mutex_spin_exit(&tty_lock); 368 vprele = sp->s_ttyvp; 369 sp->s_ttyvp = NULL; 370 /* 371 * s_ttyp is not zero'd; we use this to indicate 372 * that the session once had a controlling terminal. 373 * (for logging and informational purposes) 374 */ 375 } 376 sp->s_leader = NULL; 377 378 if (vprevoke != NULL || vprele != NULL) { 379 if (vprevoke != NULL) { 380 /* Releases proc_lock. */ 381 proc_sessrele(sp); 382 VOP_REVOKE(vprevoke, REVOKEALL); 383 } else 384 mutex_exit(proc_lock); 385 if (vprele != NULL) 386 vrele(vprele); 387 mutex_enter(proc_lock); 388 } 389 } 390 fixjobc(p, p->p_pgrp, 0); 391 392 /* 393 * Finalize the last LWP's specificdata, as well as the 394 * specificdata for the proc itself. 395 */ 396 lwp_finispecific(l); 397 proc_finispecific(p); 398 399 /* 400 * Notify interested parties of our demise. 401 */ 402 KNOTE(&p->p_klist, NOTE_EXIT); 403 404 SDT_PROBE(proc,,,exit, 405 (WCOREDUMP(rv) ? CLD_DUMPED : 406 (WIFSIGNALED(rv) ? CLD_KILLED : CLD_EXITED)), 407 0,0,0,0); 408 409 #if PERFCTRS 410 /* 411 * Save final PMC information in parent process & clean up. 412 */ 413 if (PMC_ENABLED(p)) { 414 pmc_save_context(p); 415 pmc_accumulate(p->p_pptr, p); 416 pmc_process_exit(p); 417 } 418 #endif 419 420 /* 421 * Reset p_opptr pointer of all former children which got 422 * traced by another process and were reparented. We reset 423 * it to NULL here; the trace detach code then reparents 424 * the child to initproc. We only check allproc list, since 425 * eventual former children on zombproc list won't reference 426 * p_opptr anymore. 427 */ 428 if (__predict_false(p->p_slflag & PSL_CHTRACED)) { 429 PROCLIST_FOREACH(q, &allproc) { 430 if (q->p_opptr == p) 431 q->p_opptr = NULL; 432 } 433 } 434 435 /* 436 * Give orphaned children to init(8). 437 */ 438 q = LIST_FIRST(&p->p_children); 439 wakeinit = (q != NULL); 440 for (; q != NULL; q = nq) { 441 nq = LIST_NEXT(q, p_sibling); 442 443 /* 444 * Traced processes are killed since their existence 445 * means someone is screwing up. Since we reset the 446 * trace flags, the logic in sys_wait4() would not be 447 * triggered to reparent the process to its 448 * original parent, so we must do this here. 449 */ 450 if (__predict_false(q->p_slflag & PSL_TRACED)) { 451 mutex_enter(p->p_lock); 452 q->p_slflag &= ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); 453 mutex_exit(p->p_lock); 454 if (q->p_opptr != q->p_pptr) { 455 struct proc *t = q->p_opptr; 456 proc_reparent(q, t ? t : initproc); 457 q->p_opptr = NULL; 458 } else 459 proc_reparent(q, initproc); 460 killproc(q, "orphaned traced process"); 461 } else 462 proc_reparent(q, initproc); 463 } 464 465 /* 466 * Move proc from allproc to zombproc, it's now nearly ready to be 467 * collected by parent. 468 */ 469 LIST_REMOVE(l, l_list); 470 LIST_REMOVE(p, p_list); 471 LIST_INSERT_HEAD(&zombproc, p, p_list); 472 473 /* 474 * Mark the process as dead. We must do this before we signal 475 * the parent. 476 */ 477 p->p_stat = SDEAD; 478 479 /* Put in front of parent's sibling list for parent to collect it */ 480 q = p->p_pptr; 481 q->p_nstopchild++; 482 if (LIST_FIRST(&q->p_children) != p) { 483 /* Put child where it can be found quickly */ 484 LIST_REMOVE(p, p_sibling); 485 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 486 } 487 488 /* 489 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 490 * flag set, notify init instead (and hope it will handle 491 * this situation). 492 */ 493 if (q->p_flag & (PK_NOCLDWAIT|PK_CLDSIGIGN)) { 494 proc_reparent(p, initproc); 495 wakeinit = 1; 496 497 /* 498 * If this was the last child of our parent, notify 499 * parent, so in case he was wait(2)ing, he will 500 * continue. 501 */ 502 if (LIST_FIRST(&q->p_children) == NULL) 503 cv_broadcast(&q->p_waitcv); 504 } 505 506 /* Reload parent pointer, since p may have been reparented above */ 507 q = p->p_pptr; 508 509 if (__predict_false((p->p_slflag & PSL_FSTRACE) == 0 && 510 p->p_exitsig != 0)) { 511 exit_psignal(p, q, &ksi); 512 kpsignal(q, &ksi, NULL); 513 } 514 515 /* Calculate the final rusage info. */ 516 calcru(p, &p->p_stats->p_ru.ru_utime, &p->p_stats->p_ru.ru_stime, 517 NULL, NULL); 518 519 if (wakeinit) 520 cv_broadcast(&initproc->p_waitcv); 521 522 callout_destroy(&l->l_timeout_ch); 523 524 /* 525 * Release any PCU resources before becoming a zombie. 526 */ 527 pcu_discard_all(l); 528 529 /* 530 * Remaining lwp resources will be freed in lwp_exit2() once we've 531 * switch to idle context; at that point, we will be marked as a 532 * full blown zombie. 533 */ 534 mutex_enter(p->p_lock); 535 lwp_drainrefs(l); 536 lwp_lock(l); 537 l->l_prflag &= ~LPR_DETACHED; 538 l->l_stat = LSZOMB; 539 lwp_unlock(l); 540 KASSERT(curlwp == l); 541 KASSERT(p->p_nrlwps == 1); 542 KASSERT(p->p_nlwps == 1); 543 p->p_stat = SZOMB; 544 p->p_nrlwps--; 545 p->p_nzlwps++; 546 p->p_ndlwps = 0; 547 mutex_exit(p->p_lock); 548 549 /* 550 * Signal the parent to collect us, and drop the proclist lock. 551 * Drop debugger/procfs lock; no new references can be gained. 552 */ 553 cv_broadcast(&p->p_pptr->p_waitcv); 554 rw_exit(&p->p_reflock); 555 mutex_exit(proc_lock); 556 557 /* Verify that we hold no locks other than the kernel lock. */ 558 LOCKDEBUG_BARRIER(&kernel_lock, 0); 559 560 /* 561 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 562 */ 563 564 /* 565 * Give machine-dependent code a chance to free any MD LWP 566 * resources. This must be done before uvm_lwp_exit(), in 567 * case these resources are in the PCB. 568 */ 569 cpu_lwp_free(l, 1); 570 /* 571 * A new child of a posix_spawn operation might never have been 572 * to userland - no pmap deactivation is needed in this case 573 */ 574 if (__predict_true(l->l_proc->p_vmspace != NULL)) 575 pmap_deactivate(l); 576 577 /* This process no longer needs to hold the kernel lock. */ 578 #ifdef notyet 579 /* XXXSMP hold in lwp_userret() */ 580 KERNEL_UNLOCK_LAST(l); 581 #else 582 KERNEL_UNLOCK_ALL(l, NULL); 583 #endif 584 585 lwp_exit_switchaway(l); 586 } 587 588 void 589 exit_lwps(struct lwp *l) 590 { 591 struct proc *p; 592 struct lwp *l2; 593 int error; 594 lwpid_t waited; 595 int nlocks; 596 597 KERNEL_UNLOCK_ALL(l, &nlocks); 598 599 p = l->l_proc; 600 KASSERT(mutex_owned(p->p_lock)); 601 retry: 602 /* 603 * Interrupt LWPs in interruptable sleep, unsuspend suspended 604 * LWPs and then wait for everyone else to finish. 605 */ 606 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 607 if (l2 == l) 608 continue; 609 lwp_lock(l2); 610 l2->l_flag |= LW_WEXIT; 611 if ((l2->l_stat == LSSLEEP && (l2->l_flag & LW_SINTR)) || 612 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 613 /* setrunnable() will release the lock. */ 614 setrunnable(l2); 615 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 616 p->p_pid, l2->l_lid)); 617 continue; 618 } 619 lwp_unlock(l2); 620 } 621 while (p->p_nlwps > 1) { 622 DPRINTF(("exit_lwps: waiting for %d LWPs (%d zombies)\n", 623 p->p_nlwps, p->p_nzlwps)); 624 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 625 if (p->p_nlwps == 1) 626 break; 627 if (error == EDEADLK) { 628 /* 629 * LWPs can get suspended/slept behind us. 630 * (eg. sa_setwoken) 631 * kick them again and retry. 632 */ 633 goto retry; 634 } 635 if (error) 636 panic("exit_lwps: lwp_wait1 failed with error %d", 637 error); 638 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 639 } 640 641 KERNEL_LOCK(nlocks, l); 642 KASSERT(p->p_nlwps == 1); 643 } 644 645 int 646 do_sys_wait(int *pid, int *status, int options, struct rusage *ru) 647 { 648 proc_t *child; 649 int error; 650 651 if (ru != NULL) { 652 memset(ru, 0, sizeof(*ru)); 653 } 654 mutex_enter(proc_lock); 655 error = find_stopped_child(curproc, *pid, options, &child, status); 656 if (child == NULL) { 657 mutex_exit(proc_lock); 658 *pid = 0; 659 return error; 660 } 661 *pid = child->p_pid; 662 663 if (child->p_stat == SZOMB) { 664 /* proc_free() will release the proc_lock. */ 665 if (options & WNOWAIT) { 666 mutex_exit(proc_lock); 667 } else { 668 proc_free(child, ru); 669 } 670 } else { 671 /* Child state must have been SSTOP. */ 672 mutex_exit(proc_lock); 673 *status = W_STOPCODE(*status); 674 } 675 return 0; 676 } 677 678 int 679 sys___wait450(struct lwp *l, const struct sys___wait450_args *uap, 680 register_t *retval) 681 { 682 /* { 683 syscallarg(int) pid; 684 syscallarg(int *) status; 685 syscallarg(int) options; 686 syscallarg(struct rusage *) rusage; 687 } */ 688 int error, status, pid = SCARG(uap, pid); 689 struct rusage ru; 690 691 error = do_sys_wait(&pid, &status, SCARG(uap, options), 692 SCARG(uap, rusage) != NULL ? &ru : NULL); 693 694 retval[0] = pid; 695 if (pid == 0) { 696 return error; 697 } 698 if (SCARG(uap, status)) { 699 error = copyout(&status, SCARG(uap, status), sizeof(status)); 700 } 701 if (SCARG(uap, rusage) && error == 0) { 702 error = copyout(&ru, SCARG(uap, rusage), sizeof(ru)); 703 } 704 return error; 705 } 706 707 /* 708 * Scan list of child processes for a child process that has stopped or 709 * exited. Used by sys_wait4 and 'compat' equivalents. 710 * 711 * Must be called with the proc_lock held, and may release while waiting. 712 */ 713 static int 714 find_stopped_child(struct proc *parent, pid_t pid, int options, 715 struct proc **child_p, int *status_p) 716 { 717 struct proc *child, *dead; 718 int error; 719 720 KASSERT(mutex_owned(proc_lock)); 721 722 if (options & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG) 723 && !(options & WOPTSCHECKED)) { 724 *child_p = NULL; 725 return EINVAL; 726 } 727 728 if (pid == 0 && !(options & WOPTSCHECKED)) 729 pid = -parent->p_pgid; 730 731 for (;;) { 732 error = ECHILD; 733 dead = NULL; 734 735 LIST_FOREACH(child, &parent->p_children, p_sibling) { 736 if (pid >= 0) { 737 if (child->p_pid != pid) { 738 child = proc_find_raw(pid); 739 if (child == NULL || 740 child->p_stat == SIDL || 741 child->p_pptr != parent) { 742 child = NULL; 743 break; 744 } 745 } 746 } else if (pid != WAIT_ANY && child->p_pgid != -pid) { 747 /* Child not in correct pgrp */ 748 continue; 749 } 750 751 /* 752 * Wait for processes with p_exitsig != SIGCHLD 753 * processes only if WALTSIG is set; wait for 754 * processes with p_exitsig == SIGCHLD only 755 * if WALTSIG is clear. 756 */ 757 if (((options & WALLSIG) == 0) && 758 (options & WALTSIG ? child->p_exitsig == SIGCHLD 759 : P_EXITSIG(child) != SIGCHLD)){ 760 if (child->p_pid == pid) { 761 child = NULL; 762 break; 763 } 764 continue; 765 } 766 767 error = 0; 768 if ((options & WNOZOMBIE) == 0) { 769 if (child->p_stat == SZOMB) 770 break; 771 if (child->p_stat == SDEAD) { 772 /* 773 * We may occasionally arrive here 774 * after receiving a signal, but 775 * immediately before the child 776 * process is zombified. The wait 777 * will be short, so avoid returning 778 * to userspace. 779 */ 780 dead = child; 781 } 782 } 783 784 if (child->p_stat == SSTOP && 785 child->p_waited == 0 && 786 (child->p_slflag & PSL_TRACED || 787 options & WUNTRACED)) { 788 if ((options & WNOWAIT) == 0) { 789 child->p_waited = 1; 790 parent->p_nstopchild--; 791 } 792 break; 793 } 794 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 795 child = NULL; 796 break; 797 } 798 } 799 800 if (child != NULL || error != 0 || 801 ((options & WNOHANG) != 0 && dead == NULL)) { 802 if (child != NULL) { 803 *status_p = child->p_xstat; 804 } 805 *child_p = child; 806 return error; 807 } 808 809 /* 810 * Wait for another child process to stop. 811 */ 812 error = cv_wait_sig(&parent->p_waitcv, proc_lock); 813 814 if (error != 0) { 815 *child_p = NULL; 816 return error; 817 } 818 } 819 } 820 821 /* 822 * Free a process after parent has taken all the state info. Must be called 823 * with the proclist lock held, and will release before returning. 824 * 825 * *ru is returned to the caller, and must be freed by the caller. 826 */ 827 static void 828 proc_free(struct proc *p, struct rusage *ru) 829 { 830 struct proc *parent = p->p_pptr; 831 struct lwp *l; 832 ksiginfo_t ksi; 833 kauth_cred_t cred1, cred2; 834 uid_t uid; 835 836 KASSERT(mutex_owned(proc_lock)); 837 KASSERT(p->p_nlwps == 1); 838 KASSERT(p->p_nzlwps == 1); 839 KASSERT(p->p_nrlwps == 0); 840 KASSERT(p->p_stat == SZOMB); 841 842 /* 843 * If we got the child via ptrace(2) or procfs, and 844 * the parent is different (meaning the process was 845 * attached, rather than run as a child), then we need 846 * to give it back to the old parent, and send the 847 * parent the exit signal. The rest of the cleanup 848 * will be done when the old parent waits on the child. 849 */ 850 if ((p->p_slflag & PSL_TRACED) != 0 && p->p_opptr != parent) { 851 mutex_enter(p->p_lock); 852 p->p_slflag &= ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); 853 mutex_exit(p->p_lock); 854 parent = (p->p_opptr == NULL) ? initproc : p->p_opptr; 855 proc_reparent(p, parent); 856 p->p_opptr = NULL; 857 if (p->p_exitsig != 0) { 858 exit_psignal(p, parent, &ksi); 859 kpsignal(parent, &ksi, NULL); 860 } 861 cv_broadcast(&parent->p_waitcv); 862 mutex_exit(proc_lock); 863 return; 864 } 865 866 sched_proc_exit(parent, p); 867 868 /* 869 * Add child times of exiting process onto its own times. 870 * This cannot be done any earlier else it might get done twice. 871 */ 872 l = LIST_FIRST(&p->p_lwps); 873 p->p_stats->p_ru.ru_nvcsw += (l->l_ncsw - l->l_nivcsw); 874 p->p_stats->p_ru.ru_nivcsw += l->l_nivcsw; 875 ruadd(&p->p_stats->p_ru, &l->l_ru); 876 ruadd(&p->p_stats->p_ru, &p->p_stats->p_cru); 877 ruadd(&parent->p_stats->p_cru, &p->p_stats->p_ru); 878 if (ru != NULL) 879 *ru = p->p_stats->p_ru; 880 p->p_xstat = 0; 881 882 /* 883 * At this point we are going to start freeing the final resources. 884 * If anyone tries to access the proc structure after here they will 885 * get a shock - bits are missing. Attempt to make it hard! We 886 * don't bother with any further locking past this point. 887 */ 888 p->p_stat = SIDL; /* not even a zombie any more */ 889 LIST_REMOVE(p, p_list); /* off zombproc */ 890 parent->p_nstopchild--; 891 LIST_REMOVE(p, p_sibling); 892 893 /* 894 * Let pid be reallocated. 895 */ 896 proc_free_pid(p->p_pid); 897 898 /* 899 * Unlink process from its process group. 900 * Releases the proc_lock. 901 */ 902 proc_leavepgrp(p); 903 904 /* 905 * Delay release until after lwp_free. 906 */ 907 cred2 = l->l_cred; 908 909 /* 910 * Free the last LWP's resources. 911 * 912 * lwp_free ensures the LWP is no longer running on another CPU. 913 */ 914 lwp_free(l, false, true); 915 916 /* 917 * Now no one except us can reach the process p. 918 */ 919 920 /* 921 * Decrement the count of procs running with this uid. 922 */ 923 cred1 = p->p_cred; 924 uid = kauth_cred_getuid(cred1); 925 (void)chgproccnt(uid, -1); 926 927 /* 928 * Release substructures. 929 */ 930 931 lim_free(p->p_limit); 932 pstatsfree(p->p_stats); 933 kauth_cred_free(cred1); 934 kauth_cred_free(cred2); 935 936 /* 937 * Release reference to text vnode 938 */ 939 if (p->p_textvp) 940 vrele(p->p_textvp); 941 942 mutex_destroy(&p->p_auxlock); 943 mutex_obj_free(p->p_lock); 944 mutex_destroy(&p->p_stmutex); 945 cv_destroy(&p->p_waitcv); 946 cv_destroy(&p->p_lwpcv); 947 rw_destroy(&p->p_reflock); 948 949 proc_free_mem(p); 950 } 951 952 /* 953 * make process 'parent' the new parent of process 'child'. 954 * 955 * Must be called with proc_lock held. 956 */ 957 void 958 proc_reparent(struct proc *child, struct proc *parent) 959 { 960 961 KASSERT(mutex_owned(proc_lock)); 962 963 if (child->p_pptr == parent) 964 return; 965 966 if (child->p_stat == SZOMB || 967 (child->p_stat == SSTOP && !child->p_waited)) { 968 child->p_pptr->p_nstopchild--; 969 parent->p_nstopchild++; 970 } 971 if (parent == initproc) 972 child->p_exitsig = SIGCHLD; 973 974 LIST_REMOVE(child, p_sibling); 975 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 976 child->p_pptr = parent; 977 child->p_ppid = parent->p_pid; 978 } 979