1 /* $NetBSD: kern_exit.c,v 1.211 2008/06/16 09:51:14 ad 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 1.211 2008/06/16 09:51:14 ad 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/aio.h> 78 #include <sys/systm.h> 79 #include <sys/ioctl.h> 80 #include <sys/tty.h> 81 #include <sys/time.h> 82 #include <sys/resource.h> 83 #include <sys/kernel.h> 84 #include <sys/proc.h> 85 #include <sys/buf.h> 86 #include <sys/wait.h> 87 #include <sys/file.h> 88 #include <sys/vnode.h> 89 #include <sys/syslog.h> 90 #include <sys/malloc.h> 91 #include <sys/pool.h> 92 #include <sys/resourcevar.h> 93 #if defined(PERFCTRS) 94 #include <sys/pmc.h> 95 #endif 96 #include <sys/ptrace.h> 97 #include <sys/acct.h> 98 #include <sys/filedesc.h> 99 #include <sys/ras.h> 100 #include <sys/signalvar.h> 101 #include <sys/sched.h> 102 #include <sys/mount.h> 103 #include <sys/syscallargs.h> 104 #include <sys/kauth.h> 105 #include <sys/sleepq.h> 106 #include <sys/lockdebug.h> 107 #include <sys/ktrace.h> 108 #include <sys/cpu.h> 109 #include <sys/lwpctl.h> 110 #include <sys/atomic.h> 111 112 #include <uvm/uvm_extern.h> 113 114 #define DEBUG_EXIT 115 116 #ifdef DEBUG_EXIT 117 int debug_exit = 0; 118 #define DPRINTF(x) if (debug_exit) printf x 119 #else 120 #define DPRINTF(x) 121 #endif 122 123 static int find_stopped_child(struct proc *, pid_t, int, struct proc **, int *); 124 static void proc_free(struct proc *, struct rusage *); 125 126 /* 127 * Fill in the appropriate signal information, and signal the parent. 128 */ 129 static void 130 exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi) 131 { 132 133 KSI_INIT(ksi); 134 if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) { 135 if (WIFSIGNALED(p->p_xstat)) { 136 if (WCOREDUMP(p->p_xstat)) 137 ksi->ksi_code = CLD_DUMPED; 138 else 139 ksi->ksi_code = CLD_KILLED; 140 } else { 141 ksi->ksi_code = CLD_EXITED; 142 } 143 } 144 /* 145 * We fill those in, even for non-SIGCHLD. 146 * It's safe to access p->p_cred unlocked here. 147 */ 148 ksi->ksi_pid = p->p_pid; 149 ksi->ksi_uid = kauth_cred_geteuid(p->p_cred); 150 ksi->ksi_status = p->p_xstat; 151 /* XXX: is this still valid? */ 152 ksi->ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; 153 ksi->ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; 154 } 155 156 /* 157 * exit -- 158 * Death of process. 159 */ 160 int 161 sys_exit(struct lwp *l, const struct sys_exit_args *uap, register_t *retval) 162 { 163 /* { 164 syscallarg(int) rval; 165 } */ 166 struct proc *p = l->l_proc; 167 168 /* Don't call exit1() multiple times in the same process. */ 169 mutex_enter(p->p_lock); 170 if (p->p_sflag & PS_WEXIT) { 171 mutex_exit(p->p_lock); 172 lwp_exit(l); 173 } 174 175 /* exit1() will release the mutex. */ 176 exit1(l, W_EXITCODE(SCARG(uap, rval), 0)); 177 /* NOTREACHED */ 178 return (0); 179 } 180 181 /* 182 * Exit: deallocate address space and other resources, change proc state 183 * to zombie, and unlink proc from allproc and parent's lists. Save exit 184 * status and rusage for wait(). Check for child processes and orphan them. 185 * 186 * Must be called with p->p_lock held. Does not return. 187 */ 188 void 189 exit1(struct lwp *l, int rv) 190 { 191 struct proc *p, *q, *nq; 192 struct pgrp *pgrp; 193 ksiginfo_t ksi; 194 ksiginfoq_t kq; 195 int wakeinit; 196 197 p = l->l_proc; 198 199 KASSERT(mutex_owned(p->p_lock)); 200 201 if (__predict_false(p == initproc)) 202 panic("init died (signal %d, exit %d)", 203 WTERMSIG(rv), WEXITSTATUS(rv)); 204 205 p->p_sflag |= PS_WEXIT; 206 207 /* 208 * Force all other LWPs to exit before we do. Only then can we 209 * begin to tear down the rest of the process state. 210 */ 211 if (p->p_nlwps > 1) 212 exit_lwps(l); 213 214 ksiginfo_queue_init(&kq); 215 216 /* 217 * If we have been asked to stop on exit, do so now. 218 */ 219 if (__predict_false(p->p_sflag & PS_STOPEXIT)) { 220 KERNEL_UNLOCK_ALL(l, &l->l_biglocks); 221 sigclearall(p, &contsigmask, &kq); 222 p->p_waited = 0; 223 membar_producer(); 224 p->p_stat = SSTOP; 225 lwp_lock(l); 226 p->p_nrlwps--; 227 l->l_stat = LSSTOP; 228 mutex_exit(p->p_lock); 229 mi_switch(l); 230 KERNEL_LOCK(l->l_biglocks, l); 231 mutex_enter(p->p_lock); 232 } 233 234 /* 235 * Bin any remaining signals and mark the process as dying so it will 236 * not be found for, e.g. signals. 237 */ 238 sigfillset(&p->p_sigctx.ps_sigignore); 239 sigclearall(p, NULL, &kq); 240 p->p_stat = SDYING; 241 mutex_exit(p->p_lock); 242 ksiginfo_queue_drain(&kq); 243 244 /* Destroy any lwpctl info. */ 245 if (p->p_lwpctl != NULL) 246 lwp_ctl_exit(); 247 248 /* Destroy all AIO works */ 249 aio_exit(p, p->p_aio); 250 251 /* 252 * Drain all remaining references that procfs, ptrace and others may 253 * have on the process. 254 */ 255 rw_enter(&p->p_reflock, RW_WRITER); 256 257 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid)); 258 259 timers_free(p, TIMERS_ALL); 260 #if defined(__HAVE_RAS) 261 ras_purgeall(); 262 #endif 263 264 /* 265 * Close open files, release open-file table and free signal 266 * actions. This may block! 267 */ 268 fd_free(); 269 cwdfree(p->p_cwdi); 270 p->p_cwdi = NULL; 271 doexithooks(p); 272 sigactsfree(p->p_sigacts); 273 274 /* 275 * Write out accounting data. 276 */ 277 (void)acct_process(l); 278 279 #ifdef KTRACE 280 /* 281 * Release trace file. 282 */ 283 if (p->p_tracep != NULL) { 284 mutex_enter(&ktrace_lock); 285 ktrderef(p); 286 mutex_exit(&ktrace_lock); 287 } 288 #endif 289 290 /* 291 * If emulation has process exit hook, call it now. 292 * Set the exit status now so that the exit hook has 293 * an opportunity to tweak it (COMPAT_LINUX requires 294 * this for thread group emulation) 295 */ 296 p->p_xstat = rv; 297 if (p->p_emul->e_proc_exit) 298 (*p->p_emul->e_proc_exit)(p); 299 300 /* 301 * Free the VM resources we're still holding on to. 302 * We must do this from a valid thread because doing 303 * so may block. This frees vmspace, which we don't 304 * need anymore. The only remaining lwp is the one 305 * we run at this moment, nothing runs in userland 306 * anymore. 307 */ 308 uvm_proc_exit(p); 309 310 /* 311 * Stop profiling. 312 */ 313 if (__predict_false((p->p_stflag & PST_PROFIL) != 0)) { 314 mutex_spin_enter(&p->p_stmutex); 315 stopprofclock(p); 316 mutex_spin_exit(&p->p_stmutex); 317 } 318 319 /* 320 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 321 * wake up the parent early to avoid deadlock. We can do this once 322 * the VM resources are released. 323 */ 324 mutex_enter(proc_lock); 325 if (p->p_lflag & PL_PPWAIT) { 326 p->p_lflag &= ~PL_PPWAIT; 327 cv_broadcast(&p->p_pptr->p_waitcv); 328 } 329 330 if (SESS_LEADER(p)) { 331 struct vnode *vprele = NULL, *vprevoke = NULL; 332 struct session *sp = p->p_session; 333 struct tty *tp; 334 335 if (sp->s_ttyvp) { 336 /* 337 * Controlling process. 338 * Signal foreground pgrp, 339 * drain controlling terminal 340 * and revoke access to controlling terminal. 341 */ 342 tp = sp->s_ttyp; 343 mutex_spin_enter(&tty_lock); 344 if (tp->t_session == sp) { 345 /* we can't guarantee the revoke will do this */ 346 pgrp = tp->t_pgrp; 347 tp->t_pgrp = NULL; 348 tp->t_session = NULL; 349 mutex_spin_exit(&tty_lock); 350 if (pgrp != NULL) { 351 pgsignal(pgrp, SIGHUP, 1); 352 } 353 mutex_exit(proc_lock); 354 (void) ttywait(tp); 355 mutex_enter(proc_lock); 356 357 /* The tty could have been revoked. */ 358 vprevoke = sp->s_ttyvp; 359 } else 360 mutex_spin_exit(&tty_lock); 361 vprele = sp->s_ttyvp; 362 sp->s_ttyvp = NULL; 363 /* 364 * s_ttyp is not zero'd; we use this to indicate 365 * that the session once had a controlling terminal. 366 * (for logging and informational purposes) 367 */ 368 } 369 sp->s_leader = NULL; 370 371 if (vprevoke != NULL || vprele != NULL) { 372 if (vprevoke != NULL) { 373 SESSRELE(sp); 374 mutex_exit(proc_lock); 375 VOP_REVOKE(vprevoke, REVOKEALL); 376 } else 377 mutex_exit(proc_lock); 378 if (vprele != NULL) 379 vrele(vprele); 380 mutex_enter(proc_lock); 381 } 382 } 383 fixjobc(p, p->p_pgrp, 0); 384 385 /* 386 * Finalize the last LWP's specificdata, as well as the 387 * specificdata for the proc itself. 388 */ 389 lwp_finispecific(l); 390 proc_finispecific(p); 391 392 /* 393 * Notify interested parties of our demise. 394 */ 395 KNOTE(&p->p_klist, NOTE_EXIT); 396 397 #if PERFCTRS 398 /* 399 * Save final PMC information in parent process & clean up. 400 */ 401 if (PMC_ENABLED(p)) { 402 pmc_save_context(p); 403 pmc_accumulate(p->p_pptr, p); 404 pmc_process_exit(p); 405 } 406 #endif 407 408 /* 409 * Reset p_opptr pointer of all former children which got 410 * traced by another process and were reparented. We reset 411 * it to NULL here; the trace detach code then reparents 412 * the child to initproc. We only check allproc list, since 413 * eventual former children on zombproc list won't reference 414 * p_opptr anymore. 415 */ 416 if (__predict_false(p->p_slflag & PSL_CHTRACED)) { 417 PROCLIST_FOREACH(q, &allproc) { 418 if ((q->p_flag & PK_MARKER) != 0) 419 continue; 420 if (q->p_opptr == p) 421 q->p_opptr = NULL; 422 } 423 } 424 425 /* 426 * Give orphaned children to init(8). 427 */ 428 q = LIST_FIRST(&p->p_children); 429 wakeinit = (q != NULL); 430 for (; q != NULL; q = nq) { 431 nq = LIST_NEXT(q, p_sibling); 432 433 /* 434 * Traced processes are killed since their existence 435 * means someone is screwing up. Since we reset the 436 * trace flags, the logic in sys_wait4() would not be 437 * triggered to reparent the process to its 438 * original parent, so we must do this here. 439 */ 440 if (__predict_false(q->p_slflag & PSL_TRACED)) { 441 mutex_enter(p->p_lock); 442 q->p_slflag &= ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); 443 mutex_exit(p->p_lock); 444 if (q->p_opptr != q->p_pptr) { 445 struct proc *t = q->p_opptr; 446 proc_reparent(q, t ? t : initproc); 447 q->p_opptr = NULL; 448 } else 449 proc_reparent(q, initproc); 450 killproc(q, "orphaned traced process"); 451 } else 452 proc_reparent(q, initproc); 453 } 454 455 /* 456 * Move proc from allproc to zombproc, it's now nearly ready to be 457 * collected by parent. 458 */ 459 LIST_REMOVE(l, l_list); 460 LIST_REMOVE(p, p_list); 461 LIST_INSERT_HEAD(&zombproc, p, p_list); 462 463 /* 464 * Mark the process as dead. We must do this before we signal 465 * the parent. 466 */ 467 p->p_stat = SDEAD; 468 469 /* Put in front of parent's sibling list for parent to collect it */ 470 q = p->p_pptr; 471 q->p_nstopchild++; 472 if (LIST_FIRST(&q->p_children) != p) { 473 /* Put child where it can be found quickly */ 474 LIST_REMOVE(p, p_sibling); 475 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 476 } 477 478 /* 479 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 480 * flag set, notify init instead (and hope it will handle 481 * this situation). 482 */ 483 if (q->p_flag & (PK_NOCLDWAIT|PK_CLDSIGIGN)) { 484 proc_reparent(p, initproc); 485 wakeinit = 1; 486 487 /* 488 * If this was the last child of our parent, notify 489 * parent, so in case he was wait(2)ing, he will 490 * continue. 491 */ 492 if (LIST_FIRST(&q->p_children) == NULL) 493 cv_broadcast(&q->p_waitcv); 494 } 495 496 /* Reload parent pointer, since p may have been reparented above */ 497 q = p->p_pptr; 498 499 if (__predict_false((p->p_slflag & PSL_FSTRACE) == 0 && p->p_exitsig != 0)) { 500 exit_psignal(p, q, &ksi); 501 kpsignal(q, &ksi, NULL); 502 } 503 504 /* Calculate the final rusage info. */ 505 calcru(p, &p->p_stats->p_ru.ru_utime, &p->p_stats->p_ru.ru_stime, 506 NULL, NULL); 507 508 if (wakeinit) 509 cv_broadcast(&initproc->p_waitcv); 510 511 callout_destroy(&l->l_timeout_ch); 512 513 /* 514 * Remaining lwp resources will be freed in lwp_exit2() once we've 515 * switch to idle context; at that point, we will be marked as a 516 * full blown zombie. 517 */ 518 mutex_enter(p->p_lock); 519 lwp_drainrefs(l); 520 lwp_lock(l); 521 l->l_prflag &= ~LPR_DETACHED; 522 l->l_stat = LSZOMB; 523 lwp_unlock(l); 524 KASSERT(curlwp == l); 525 KASSERT(p->p_nrlwps == 1); 526 KASSERT(p->p_nlwps == 1); 527 p->p_stat = SZOMB; 528 p->p_nrlwps--; 529 p->p_nzlwps++; 530 p->p_ndlwps = 0; 531 mutex_exit(p->p_lock); 532 533 /* 534 * Signal the parent to collect us, and drop the proclist lock. 535 * Drop debugger/procfs lock; no new references can be gained. 536 */ 537 cv_broadcast(&p->p_pptr->p_waitcv); 538 mutex_exit(proc_lock); 539 rw_exit(&p->p_reflock); 540 541 /* Verify that we hold no locks other than the kernel lock. */ 542 LOCKDEBUG_BARRIER(&kernel_lock, 0); 543 544 /* 545 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 546 */ 547 548 /* 549 * Give machine-dependent code a chance to free any MD LWP 550 * resources. This must be done before uvm_lwp_exit(), in 551 * case these resources are in the PCB. 552 */ 553 #ifndef __NO_CPU_LWP_FREE 554 cpu_lwp_free(l, 1); 555 #endif 556 pmap_deactivate(l); 557 558 /* This process no longer needs to hold the kernel lock. */ 559 #ifdef notyet 560 /* XXXSMP hold in lwp_userret() */ 561 KERNEL_UNLOCK_LAST(l); 562 #else 563 KERNEL_UNLOCK_ALL(l, NULL); 564 #endif 565 566 lwp_exit_switchaway(l); 567 } 568 569 void 570 exit_lwps(struct lwp *l) 571 { 572 struct proc *p; 573 struct lwp *l2; 574 int error; 575 lwpid_t waited; 576 int nlocks; 577 578 KERNEL_UNLOCK_ALL(l, &nlocks); 579 580 p = l->l_proc; 581 KASSERT(mutex_owned(p->p_lock)); 582 583 retry: 584 /* 585 * Interrupt LWPs in interruptable sleep, unsuspend suspended 586 * LWPs and then wait for everyone else to finish. 587 */ 588 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 589 if (l2 == l) 590 continue; 591 lwp_lock(l2); 592 l2->l_flag |= LW_WEXIT; 593 if ((l2->l_stat == LSSLEEP && (l2->l_flag & LW_SINTR)) || 594 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 595 /* setrunnable() will release the lock. */ 596 setrunnable(l2); 597 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 598 p->p_pid, l2->l_lid)); 599 continue; 600 } 601 lwp_unlock(l2); 602 } 603 while (p->p_nlwps > 1) { 604 DPRINTF(("exit_lwps: waiting for %d LWPs (%d zombies)\n", 605 p->p_nlwps, p->p_nzlwps)); 606 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 607 if (p->p_nlwps == 1) 608 break; 609 if (error == EDEADLK) { 610 /* 611 * LWPs can get suspended/slept behind us. 612 * (eg. sa_setwoken) 613 * kick them again and retry. 614 */ 615 goto retry; 616 } 617 if (error) 618 panic("exit_lwps: lwp_wait1 failed with error %d", 619 error); 620 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 621 } 622 623 KERNEL_LOCK(nlocks, l); 624 KASSERT(p->p_nlwps == 1); 625 } 626 627 int 628 do_sys_wait(struct lwp *l, int *pid, int *status, int options, 629 struct rusage *ru, int *was_zombie) 630 { 631 struct proc *child; 632 int error; 633 634 mutex_enter(proc_lock); 635 error = find_stopped_child(l->l_proc, *pid, options, &child, status); 636 637 if (child == NULL) { 638 mutex_exit(proc_lock); 639 *pid = 0; 640 return error; 641 } 642 643 *pid = child->p_pid; 644 645 if (child->p_stat == SZOMB) { 646 /* proc_free() will release the proc_lock. */ 647 *was_zombie = 1; 648 if (options & WNOWAIT) 649 mutex_exit(proc_lock); 650 else { 651 proc_free(child, ru); 652 } 653 } else { 654 /* Child state must have been SSTOP. */ 655 *was_zombie = 0; 656 mutex_exit(proc_lock); 657 *status = W_STOPCODE(*status); 658 } 659 660 return 0; 661 } 662 663 int 664 sys_wait4(struct lwp *l, const struct sys_wait4_args *uap, register_t *retval) 665 { 666 /* { 667 syscallarg(int) pid; 668 syscallarg(int *) status; 669 syscallarg(int) options; 670 syscallarg(struct rusage *) rusage; 671 } */ 672 int status, error; 673 int was_zombie; 674 struct rusage ru; 675 int pid = SCARG(uap, pid); 676 677 error = do_sys_wait(l, &pid, &status, SCARG(uap, options), 678 SCARG(uap, rusage) != NULL ? &ru : NULL, &was_zombie); 679 680 retval[0] = pid; 681 if (pid == 0) 682 return error; 683 684 if (SCARG(uap, rusage)) 685 error = copyout(&ru, SCARG(uap, rusage), sizeof(ru)); 686 687 if (error == 0 && SCARG(uap, status)) 688 error = copyout(&status, SCARG(uap, status), sizeof(status)); 689 690 return error; 691 } 692 693 /* 694 * Scan list of child processes for a child process that has stopped or 695 * exited. Used by sys_wait4 and 'compat' equivalents. 696 * 697 * Must be called with the proc_lock held, and may release while waiting. 698 */ 699 static int 700 find_stopped_child(struct proc *parent, pid_t pid, int options, 701 struct proc **child_p, int *status_p) 702 { 703 struct proc *child, *dead; 704 int error; 705 706 KASSERT(mutex_owned(proc_lock)); 707 708 if (options & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG) 709 && !(options & WOPTSCHECKED)) { 710 *child_p = NULL; 711 return EINVAL; 712 } 713 714 if (pid == 0 && !(options & WOPTSCHECKED)) 715 pid = -parent->p_pgid; 716 717 for (;;) { 718 error = ECHILD; 719 dead = NULL; 720 721 LIST_FOREACH(child, &parent->p_children, p_sibling) { 722 if (pid >= 0) { 723 if (child->p_pid != pid) { 724 child = p_find(pid, PFIND_ZOMBIE | 725 PFIND_LOCKED); 726 if (child == NULL || 727 child->p_pptr != parent) { 728 child = NULL; 729 break; 730 } 731 } 732 } else if (pid != WAIT_ANY && child->p_pgid != -pid) { 733 /* Child not in correct pgrp */ 734 continue; 735 } 736 737 /* 738 * Wait for processes with p_exitsig != SIGCHLD 739 * processes only if WALTSIG is set; wait for 740 * processes with p_exitsig == SIGCHLD only 741 * if WALTSIG is clear. 742 */ 743 if (((options & WALLSIG) == 0) && 744 (options & WALTSIG ? child->p_exitsig == SIGCHLD 745 : P_EXITSIG(child) != SIGCHLD)){ 746 if (child->p_pid == pid) { 747 child = NULL; 748 break; 749 } 750 continue; 751 } 752 753 error = 0; 754 if ((options & WNOZOMBIE) == 0) { 755 if (child->p_stat == SZOMB) 756 break; 757 if (child->p_stat == SDEAD) { 758 /* 759 * We may occasionally arrive here 760 * after receiving a signal, but 761 * immediatley before the child 762 * process is zombified. The wait 763 * will be short, so avoid returning 764 * to userspace. 765 */ 766 dead = child; 767 } 768 } 769 770 if (child->p_stat == SSTOP && 771 child->p_waited == 0 && 772 (child->p_slflag & PSL_TRACED || 773 options & WUNTRACED)) { 774 if ((options & WNOWAIT) == 0) { 775 child->p_waited = 1; 776 parent->p_nstopchild--; 777 } 778 break; 779 } 780 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 781 child = NULL; 782 break; 783 } 784 } 785 786 if (child != NULL || error != 0 || 787 ((options & WNOHANG) != 0 && dead == NULL)) { 788 if (child != NULL) { 789 *status_p = child->p_xstat; 790 } 791 *child_p = child; 792 return error; 793 } 794 795 /* 796 * Wait for another child process to stop. 797 */ 798 error = cv_wait_sig(&parent->p_waitcv, proc_lock); 799 800 if (error != 0) { 801 *child_p = NULL; 802 return error; 803 } 804 } 805 } 806 807 /* 808 * Free a process after parent has taken all the state info. Must be called 809 * with the proclist lock held, and will release before returning. 810 * 811 * *ru is returned to the caller, and must be freed by the caller. 812 */ 813 static void 814 proc_free(struct proc *p, struct rusage *ru) 815 { 816 struct proc *parent; 817 struct lwp *l; 818 ksiginfo_t ksi; 819 kauth_cred_t cred1, cred2; 820 uid_t uid; 821 822 KASSERT(mutex_owned(proc_lock)); 823 KASSERT(p->p_nlwps == 1); 824 KASSERT(p->p_nzlwps == 1); 825 KASSERT(p->p_nrlwps == 0); 826 KASSERT(p->p_stat == SZOMB); 827 828 /* 829 * If we got the child via ptrace(2) or procfs, and 830 * the parent is different (meaning the process was 831 * attached, rather than run as a child), then we need 832 * to give it back to the old parent, and send the 833 * parent the exit signal. The rest of the cleanup 834 * will be done when the old parent waits on the child. 835 */ 836 if ((p->p_slflag & PSL_TRACED) != 0) { 837 parent = p->p_pptr; 838 if (p->p_opptr != parent){ 839 mutex_enter(p->p_lock); 840 p->p_slflag &= ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); 841 mutex_exit(p->p_lock); 842 parent = p->p_opptr; 843 if (parent == NULL) 844 parent = initproc; 845 proc_reparent(p, parent); 846 p->p_opptr = NULL; 847 if (p->p_exitsig != 0) { 848 exit_psignal(p, parent, &ksi); 849 kpsignal(parent, &ksi, NULL); 850 } 851 cv_broadcast(&parent->p_waitcv); 852 mutex_exit(proc_lock); 853 return; 854 } 855 } 856 857 /* 858 * Finally finished with old proc entry. Unlink it from its process 859 * group. 860 */ 861 leavepgrp(p); 862 863 parent = p->p_pptr; 864 sched_proc_exit(parent, p); 865 866 /* 867 * Add child times of exiting process onto its own times. 868 * This cannot be done any earlier else it might get done twice. 869 */ 870 l = LIST_FIRST(&p->p_lwps); 871 p->p_stats->p_ru.ru_nvcsw += (l->l_ncsw - l->l_nivcsw); 872 p->p_stats->p_ru.ru_nivcsw += l->l_nivcsw; 873 ruadd(&p->p_stats->p_ru, &l->l_ru); 874 ruadd(&p->p_stats->p_ru, &p->p_stats->p_cru); 875 ruadd(&parent->p_stats->p_cru, &p->p_stats->p_ru); 876 if (ru != NULL) 877 *ru = p->p_stats->p_ru; 878 p->p_xstat = 0; 879 880 /* 881 * At this point we are going to start freeing the final resources. 882 * If anyone tries to access the proc structure after here they will 883 * get a shock - bits are missing. Attempt to make it hard! We 884 * don't bother with any further locking past this point. 885 */ 886 p->p_stat = SIDL; /* not even a zombie any more */ 887 LIST_REMOVE(p, p_list); /* off zombproc */ 888 parent = p->p_pptr; 889 p->p_pptr->p_nstopchild--; 890 LIST_REMOVE(p, p_sibling); 891 892 /* 893 * Let pid be reallocated. 894 */ 895 proc_free_pid(p); 896 mutex_exit(proc_lock); 897 898 /* 899 * Delay release until after lwp_free. 900 */ 901 cred2 = l->l_cred; 902 903 /* 904 * Free the last LWP's resources. 905 * 906 * lwp_free ensures the LWP is no longer running on another CPU. 907 */ 908 lwp_free(l, false, true); 909 910 /* 911 * Now no one except us can reach the process p. 912 */ 913 914 /* 915 * Decrement the count of procs running with this uid. 916 */ 917 cred1 = p->p_cred; 918 uid = kauth_cred_getuid(cred1); 919 (void)chgproccnt(uid, -1); 920 921 /* 922 * Release substructures. 923 */ 924 925 limfree(p->p_limit); 926 pstatsfree(p->p_stats); 927 kauth_cred_free(cred1); 928 kauth_cred_free(cred2); 929 930 /* 931 * Release reference to text vnode 932 */ 933 if (p->p_textvp) 934 vrele(p->p_textvp); 935 936 mutex_destroy(&p->p_auxlock); 937 mutex_obj_free(p->p_lock); 938 mutex_destroy(&p->p_stmutex); 939 cv_destroy(&p->p_waitcv); 940 cv_destroy(&p->p_lwpcv); 941 rw_destroy(&p->p_reflock); 942 943 proc_free_mem(p); 944 } 945 946 /* 947 * make process 'parent' the new parent of process 'child'. 948 * 949 * Must be called with proc_lock held. 950 */ 951 void 952 proc_reparent(struct proc *child, struct proc *parent) 953 { 954 955 KASSERT(mutex_owned(proc_lock)); 956 957 if (child->p_pptr == parent) 958 return; 959 960 if (child->p_stat == SZOMB || 961 (child->p_stat == SSTOP && !child->p_waited)) { 962 child->p_pptr->p_nstopchild--; 963 parent->p_nstopchild++; 964 } 965 if (parent == initproc) 966 child->p_exitsig = SIGCHLD; 967 968 LIST_REMOVE(child, p_sibling); 969 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 970 child->p_pptr = parent; 971 child->p_ppid = parent->p_pid; 972 } 973