1 /* $NetBSD: kern_exit.c,v 1.199 2008/01/28 12:22:46 yamt Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 1999, 2006, 2007 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 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1989, 1991, 1993 42 * The Regents of the University of California. All rights reserved. 43 * (c) UNIX System Laboratories, Inc. 44 * All or some portions of this file are derived from material licensed 45 * to the University of California by American Telephone and Telegraph 46 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 47 * the permission of UNIX System Laboratories, Inc. 48 * 49 * Redistribution and use in source and binary forms, with or without 50 * modification, are permitted provided that the following conditions 51 * are met: 52 * 1. Redistributions of source code must retain the above copyright 53 * notice, this list of conditions and the following disclaimer. 54 * 2. Redistributions in binary form must reproduce the above copyright 55 * notice, this list of conditions and the following disclaimer in the 56 * documentation and/or other materials provided with the distribution. 57 * 3. Neither the name of the University nor the names of its contributors 58 * may be used to endorse or promote products derived from this software 59 * without specific prior written permission. 60 * 61 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 62 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 63 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 64 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 65 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 66 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 67 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 68 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 69 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 70 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 71 * SUCH DAMAGE. 72 * 73 * @(#)kern_exit.c 8.10 (Berkeley) 2/23/95 74 */ 75 76 #include <sys/cdefs.h> 77 __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.199 2008/01/28 12:22:46 yamt Exp $"); 78 79 #include "opt_ktrace.h" 80 #include "opt_perfctrs.h" 81 #include "opt_sysv.h" 82 83 #include <sys/param.h> 84 #include <sys/aio.h> 85 #include <sys/systm.h> 86 #include <sys/ioctl.h> 87 #include <sys/tty.h> 88 #include <sys/time.h> 89 #include <sys/resource.h> 90 #include <sys/kernel.h> 91 #include <sys/proc.h> 92 #include <sys/buf.h> 93 #include <sys/wait.h> 94 #include <sys/file.h> 95 #include <sys/vnode.h> 96 #include <sys/syslog.h> 97 #include <sys/malloc.h> 98 #include <sys/pool.h> 99 #include <sys/resourcevar.h> 100 #if defined(PERFCTRS) 101 #include <sys/pmc.h> 102 #endif 103 #include <sys/ptrace.h> 104 #include <sys/acct.h> 105 #include <sys/filedesc.h> 106 #include <sys/ras.h> 107 #include <sys/signalvar.h> 108 #include <sys/sched.h> 109 #include <sys/mount.h> 110 #include <sys/syscallargs.h> 111 #include <sys/kauth.h> 112 #include <sys/sleepq.h> 113 #include <sys/lockdebug.h> 114 #include <sys/ktrace.h> 115 #include <sys/cpu.h> 116 #include <sys/lwpctl.h> 117 #include <sys/atomic.h> 118 119 #include <uvm/uvm_extern.h> 120 121 #define DEBUG_EXIT 122 123 #ifdef DEBUG_EXIT 124 int debug_exit = 0; 125 #define DPRINTF(x) if (debug_exit) printf x 126 #else 127 #define DPRINTF(x) 128 #endif 129 130 static int find_stopped_child(struct proc *, pid_t, int, struct proc **, int *); 131 static void proc_free(struct proc *, struct rusage *); 132 133 /* 134 * Fill in the appropriate signal information, and signal the parent. 135 */ 136 static void 137 exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi) 138 { 139 140 KSI_INIT(ksi); 141 if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) { 142 if (WIFSIGNALED(p->p_xstat)) { 143 if (WCOREDUMP(p->p_xstat)) 144 ksi->ksi_code = CLD_DUMPED; 145 else 146 ksi->ksi_code = CLD_KILLED; 147 } else { 148 ksi->ksi_code = CLD_EXITED; 149 } 150 } 151 /* 152 * We fill those in, even for non-SIGCHLD. 153 * It's safe to access p->p_cred unlocked here. 154 */ 155 ksi->ksi_pid = p->p_pid; 156 ksi->ksi_uid = kauth_cred_geteuid(p->p_cred); 157 ksi->ksi_status = p->p_xstat; 158 /* XXX: is this still valid? */ 159 ksi->ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; 160 ksi->ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; 161 } 162 163 /* 164 * exit -- 165 * Death of process. 166 */ 167 int 168 sys_exit(struct lwp *l, const struct sys_exit_args *uap, register_t *retval) 169 { 170 /* { 171 syscallarg(int) rval; 172 } */ 173 struct proc *p = l->l_proc; 174 175 /* Don't call exit1() multiple times in the same process. */ 176 KERNEL_LOCK(1, NULL); 177 mutex_enter(&p->p_smutex); 178 if (p->p_sflag & PS_WEXIT) { 179 mutex_exit(&p->p_smutex); 180 lwp_exit(l); 181 } 182 183 /* exit1() will release the mutex. */ 184 exit1(l, W_EXITCODE(SCARG(uap, rval), 0)); 185 /* NOTREACHED */ 186 return (0); 187 } 188 189 /* 190 * Exit: deallocate address space and other resources, change proc state 191 * to zombie, and unlink proc from allproc and parent's lists. Save exit 192 * status and rusage for wait(). Check for child processes and orphan them. 193 * 194 * Must be called with p->p_smutex held. Does not return. 195 */ 196 void 197 exit1(struct lwp *l, int rv) 198 { 199 struct proc *p, *q, *nq; 200 ksiginfo_t ksi; 201 ksiginfoq_t kq; 202 int wakeinit; 203 204 p = l->l_proc; 205 206 KASSERT(mutex_owned(&p->p_smutex)); 207 208 if (__predict_false(p == initproc)) 209 panic("init died (signal %d, exit %d)", 210 WTERMSIG(rv), WEXITSTATUS(rv)); 211 212 p->p_sflag |= PS_WEXIT; 213 214 /* 215 * Force all other LWPs to exit before we do. Only then can we 216 * begin to tear down the rest of the process state. 217 */ 218 if (p->p_nlwps > 1) 219 exit_lwps(l); 220 221 ksiginfo_queue_init(&kq); 222 223 /* 224 * If we have been asked to stop on exit, do so now. 225 */ 226 if (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 mutex_exit(&p->p_smutex); 236 mi_switch(l); 237 KERNEL_LOCK(l->l_biglocks, l); 238 } else 239 mutex_exit(&p->p_smutex); 240 241 /* Destroy any lwpctl info. */ 242 if (p->p_lwpctl != NULL) 243 lwp_ctl_exit(); 244 245 /* Destroy all AIO works */ 246 aio_exit(p, p->p_aio); 247 248 /* 249 * Drain all remaining references that procfs, ptrace and others may 250 * have on the process. 251 */ 252 rw_enter(&p->p_reflock, RW_WRITER); 253 254 /* 255 * Bin any remaining signals and mark the process as dying so it will 256 * not be found for, e.g. signals. 257 */ 258 mutex_enter(&p->p_smutex); 259 sigfillset(&p->p_sigctx.ps_sigignore); 260 sigclearall(p, NULL, &kq); 261 p->p_stat = SDYING; 262 mutex_exit(&p->p_smutex); 263 ksiginfo_queue_drain(&kq); 264 265 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid)); 266 267 #ifdef PGINPROF 268 vmsizmon(); 269 #endif 270 timers_free(p, TIMERS_ALL); 271 #if defined(__HAVE_RAS) 272 ras_purgeall(); 273 #endif 274 275 /* 276 * Close open files, release open-file table and free signal 277 * actions. This may block! 278 */ 279 fdfree(l); 280 cwdfree(p->p_cwdi); 281 p->p_cwdi = NULL; 282 doexithooks(p); 283 sigactsfree(p->p_sigacts); 284 285 /* 286 * Write out accounting data. 287 */ 288 (void)acct_process(l); 289 290 #ifdef KTRACE 291 /* 292 * Release trace file. 293 */ 294 if (p->p_tracep != NULL) { 295 mutex_enter(&ktrace_lock); 296 ktrderef(p); 297 mutex_exit(&ktrace_lock); 298 } 299 #endif 300 301 /* 302 * If emulation has process exit hook, call it now. 303 * Set the exit status now so that the exit hook has 304 * an opportunity to tweak it (COMPAT_LINUX requires 305 * this for thread group emulation) 306 */ 307 p->p_xstat = rv; 308 if (p->p_emul->e_proc_exit) 309 (*p->p_emul->e_proc_exit)(p); 310 311 /* 312 * Free the VM resources we're still holding on to. 313 * We must do this from a valid thread because doing 314 * so may block. This frees vmspace, which we don't 315 * need anymore. The only remaining lwp is the one 316 * we run at this moment, nothing runs in userland 317 * anymore. 318 */ 319 uvm_proc_exit(p); 320 321 /* 322 * While we can still block, and mark the LWP as unswappable to 323 * prevent conflicts with the with the swapper. We also shouldn't 324 * be swapped out, because we are about to exit and will release 325 * memory. 326 */ 327 uvm_lwp_hold(l); 328 329 /* 330 * Stop profiling. 331 */ 332 if ((p->p_stflag & PST_PROFIL) != 0) { 333 mutex_spin_enter(&p->p_stmutex); 334 stopprofclock(p); 335 mutex_spin_exit(&p->p_stmutex); 336 } 337 338 /* 339 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 340 * wake up the parent early to avoid deadlock. We can do this once 341 * the VM resources are released. 342 */ 343 mutex_enter(&proclist_lock); 344 345 mutex_enter(&p->p_smutex); 346 if (p->p_sflag & PS_PPWAIT) { 347 p->p_sflag &= ~PS_PPWAIT; 348 cv_broadcast(&p->p_pptr->p_waitcv); 349 } 350 mutex_exit(&p->p_smutex); 351 352 if (SESS_LEADER(p)) { 353 struct vnode *vprele = NULL, *vprevoke = NULL; 354 struct session *sp = p->p_session; 355 struct tty *tp; 356 357 if (sp->s_ttyvp) { 358 /* 359 * Controlling process. 360 * Signal foreground pgrp, 361 * drain controlling terminal 362 * and revoke access to controlling terminal. 363 */ 364 tp = sp->s_ttyp; 365 mutex_spin_enter(&tty_lock); 366 if (tp->t_session == sp) { 367 if (tp->t_pgrp) { 368 mutex_enter(&proclist_mutex); 369 pgsignal(tp->t_pgrp, SIGHUP, 1); 370 mutex_exit(&proclist_mutex); 371 } 372 /* we can't guarantee the revoke will do this */ 373 tp->t_pgrp = NULL; 374 tp->t_session = NULL; 375 mutex_spin_exit(&tty_lock); 376 mutex_exit(&proclist_lock); 377 (void) ttywait(tp); 378 mutex_enter(&proclist_lock); 379 380 /* The tty could have been revoked. */ 381 vprevoke = sp->s_ttyvp; 382 } else 383 mutex_spin_exit(&tty_lock); 384 vprele = sp->s_ttyvp; 385 sp->s_ttyvp = NULL; 386 /* 387 * s_ttyp is not zero'd; we use this to indicate 388 * that the session once had a controlling terminal. 389 * (for logging and informational purposes) 390 */ 391 } 392 sp->s_leader = NULL; 393 394 if (vprevoke != NULL || vprele != NULL) { 395 if (vprevoke != NULL) { 396 SESSRELE(sp); 397 mutex_exit(&proclist_lock); 398 VOP_REVOKE(vprevoke, REVOKEALL); 399 } else 400 mutex_exit(&proclist_lock); 401 if (vprele != NULL) 402 vrele(vprele); 403 mutex_enter(&proclist_lock); 404 } 405 } 406 mutex_enter(&proclist_mutex); 407 fixjobc(p, p->p_pgrp, 0); 408 mutex_exit(&proclist_mutex); 409 410 /* 411 * Finalize the last LWP's specificdata, as well as the 412 * specificdata for the proc itself. 413 */ 414 lwp_finispecific(l); 415 proc_finispecific(p); 416 417 /* 418 * Notify interested parties of our demise. 419 */ 420 KNOTE(&p->p_klist, NOTE_EXIT); 421 422 423 424 #if PERFCTRS 425 /* 426 * Save final PMC information in parent process & clean up. 427 */ 428 if (PMC_ENABLED(p)) { 429 pmc_save_context(p); 430 pmc_accumulate(p->p_pptr, p); 431 pmc_process_exit(p); 432 } 433 #endif 434 435 /* 436 * Reset p_opptr pointer of all former children which got 437 * traced by another process and were reparented. We reset 438 * it to NULL here; the trace detach code then reparents 439 * the child to initproc. We only check allproc list, since 440 * eventual former children on zombproc list won't reference 441 * p_opptr anymore. 442 */ 443 if (p->p_slflag & PSL_CHTRACED) { 444 PROCLIST_FOREACH(q, &allproc) { 445 if (q->p_opptr == p) 446 q->p_opptr = NULL; 447 } 448 } 449 450 /* 451 * Give orphaned children to init(8). 452 */ 453 q = LIST_FIRST(&p->p_children); 454 wakeinit = (q != NULL); 455 for (; q != NULL; q = nq) { 456 nq = LIST_NEXT(q, p_sibling); 457 458 /* 459 * Traced processes are killed since their existence 460 * means someone is screwing up. Since we reset the 461 * trace flags, the logic in sys_wait4() would not be 462 * triggered to reparent the process to its 463 * original parent, so we must do this here. 464 */ 465 if (q->p_slflag & PSL_TRACED) { 466 mutex_enter(&p->p_smutex); 467 q->p_slflag &= ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); 468 mutex_exit(&p->p_smutex); 469 if (q->p_opptr != q->p_pptr) { 470 struct proc *t = q->p_opptr; 471 proc_reparent(q, t ? t : initproc); 472 q->p_opptr = NULL; 473 } else 474 proc_reparent(q, initproc); 475 killproc(q, "orphaned traced process"); 476 } else 477 proc_reparent(q, initproc); 478 } 479 480 /* 481 * Move proc from allproc to zombproc, it's now nearly ready to be 482 * collected by parent. 483 */ 484 mutex_enter(&proclist_mutex); 485 LIST_REMOVE(l, l_list); 486 LIST_REMOVE(p, p_list); 487 LIST_INSERT_HEAD(&zombproc, p, p_list); 488 489 /* 490 * Mark the process as dead. We must do this before we signal 491 * the parent. 492 */ 493 p->p_stat = SDEAD; 494 495 /* Put in front of parent's sibling list for parent to collect it */ 496 q = p->p_pptr; 497 q->p_nstopchild++; 498 if (LIST_FIRST(&q->p_children) != p) { 499 /* Put child where it can be found quickly */ 500 LIST_REMOVE(p, p_sibling); 501 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 502 } 503 mutex_exit(&proclist_mutex); 504 505 /* 506 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 507 * flag set, notify init instead (and hope it will handle 508 * this situation). 509 */ 510 mutex_enter(&q->p_mutex); 511 if (q->p_flag & (PK_NOCLDWAIT|PK_CLDSIGIGN)) { 512 proc_reparent(p, initproc); 513 wakeinit = 1; 514 515 /* 516 * If this was the last child of our parent, notify 517 * parent, so in case he was wait(2)ing, he will 518 * continue. 519 */ 520 if (LIST_FIRST(&q->p_children) == NULL) 521 cv_broadcast(&q->p_waitcv); 522 } 523 mutex_exit(&q->p_mutex); 524 525 /* Reload parent pointer, since p may have been reparented above */ 526 q = p->p_pptr; 527 528 if ((p->p_slflag & PSL_FSTRACE) == 0 && p->p_exitsig != 0) { 529 exit_psignal(p, q, &ksi); 530 mutex_enter(&proclist_mutex); 531 kpsignal(q, &ksi, NULL); 532 mutex_exit(&proclist_mutex); 533 } 534 535 /* Calculate the final rusage info. */ 536 calcru(p, &p->p_stats->p_ru.ru_utime, &p->p_stats->p_ru.ru_stime, 537 NULL, NULL); 538 539 if (wakeinit) 540 cv_broadcast(&initproc->p_waitcv); 541 542 callout_destroy(&l->l_timeout_ch); 543 544 /* 545 * Remaining lwp resources will be freed in lwp_exit2() once we've 546 * switch to idle context; at that point, we will be marked as a 547 * full blown zombie. 548 * 549 * XXXSMP disable preemption. 550 */ 551 mutex_enter(&p->p_smutex); 552 lwp_drainrefs(l); 553 lwp_lock(l); 554 l->l_prflag &= ~LPR_DETACHED; 555 l->l_stat = LSZOMB; 556 lwp_unlock(l); 557 KASSERT(curlwp == l); 558 KASSERT(p->p_nrlwps == 1); 559 KASSERT(p->p_nlwps == 1); 560 p->p_stat = SZOMB; 561 p->p_nrlwps--; 562 p->p_nzlwps++; 563 p->p_ndlwps = 0; 564 mutex_exit(&p->p_smutex); 565 566 /* 567 * Signal the parent to collect us, and drop the proclist lock. 568 * Drop debugger/procfs lock; no new references can be gained. 569 */ 570 cv_broadcast(&p->p_pptr->p_waitcv); 571 mutex_exit(&proclist_lock); 572 rw_exit(&p->p_reflock); 573 574 /* Verify that we hold no locks other than the kernel lock. */ 575 #ifdef MULTIPROCESSOR 576 LOCKDEBUG_BARRIER(&kernel_lock, 0); 577 #else 578 LOCKDEBUG_BARRIER(NULL, 0); 579 #endif 580 581 /* 582 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 583 */ 584 585 /* 586 * Give machine-dependent code a chance to free any MD LWP 587 * resources. This must be done before uvm_lwp_exit(), in 588 * case these resources are in the PCB. 589 */ 590 #ifndef __NO_CPU_LWP_FREE 591 cpu_lwp_free(l, 1); 592 #endif 593 pmap_deactivate(l); 594 595 /* This process no longer needs to hold the kernel lock. */ 596 #ifdef notyet 597 /* XXXSMP hold in lwp_userret() */ 598 KERNEL_UNLOCK_LAST(l); 599 #else 600 KERNEL_UNLOCK_ALL(l, NULL); 601 #endif 602 603 lwp_exit_switchaway(l); 604 } 605 606 void 607 exit_lwps(struct lwp *l) 608 { 609 struct proc *p; 610 struct lwp *l2; 611 int error; 612 lwpid_t waited; 613 #if defined(MULTIPROCESSOR) 614 int nlocks; 615 #endif 616 617 KERNEL_UNLOCK_ALL(l, &nlocks); 618 619 p = l->l_proc; 620 KASSERT(mutex_owned(&p->p_smutex)); 621 622 retry: 623 /* 624 * Interrupt LWPs in interruptable sleep, unsuspend suspended 625 * LWPs and then wait for everyone else to finish. 626 */ 627 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 628 if (l2 == l) 629 continue; 630 lwp_lock(l2); 631 l2->l_flag |= LW_WEXIT; 632 if ((l2->l_stat == LSSLEEP && (l2->l_flag & LW_SINTR)) || 633 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 634 /* setrunnable() will release the lock. */ 635 setrunnable(l2); 636 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 637 p->p_pid, l2->l_lid)); 638 continue; 639 } 640 lwp_unlock(l2); 641 } 642 while (p->p_nlwps > 1) { 643 DPRINTF(("exit_lwps: waiting for %d LWPs (%d zombies)\n", 644 p->p_nlwps, p->p_nzlwps)); 645 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 646 if (p->p_nlwps == 1) 647 break; 648 if (error == EDEADLK) { 649 /* 650 * LWPs can get suspended/slept behind us. 651 * (eg. sa_setwoken) 652 * kick them again and retry. 653 */ 654 goto retry; 655 } 656 if (error) 657 panic("exit_lwps: lwp_wait1 failed with error %d", 658 error); 659 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 660 } 661 662 #if defined(MULTIPROCESSOR) 663 if (nlocks > 0) { 664 mutex_exit(&p->p_smutex); 665 KERNEL_LOCK(nlocks, l); 666 mutex_enter(&p->p_smutex); 667 } 668 #endif /* defined(MULTIPROCESSOR) */ 669 KASSERT(p->p_nlwps == 1); 670 } 671 672 int 673 do_sys_wait(struct lwp *l, int *pid, int *status, int options, 674 struct rusage *ru, int *was_zombie) 675 { 676 struct proc *child; 677 int error; 678 679 KERNEL_LOCK(1, NULL); /* XXXSMP */ 680 mutex_enter(&proclist_lock); 681 error = find_stopped_child(l->l_proc, *pid, options, &child, status); 682 KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */ 683 684 if (child == NULL) { 685 mutex_exit(&proclist_lock); 686 *pid = 0; 687 return error; 688 } 689 690 *pid = child->p_pid; 691 692 if (child->p_stat == SZOMB) { 693 /* proc_free() will release the proclist_lock. */ 694 *was_zombie = 1; 695 if (options & WNOWAIT) 696 mutex_exit(&proclist_lock); 697 else { 698 proc_free(child, ru); 699 } 700 } else { 701 /* Child state must have been SSTOP. */ 702 *was_zombie = 0; 703 mutex_exit(&proclist_lock); 704 *status = W_STOPCODE(*status); 705 } 706 707 return 0; 708 } 709 710 int 711 sys_wait4(struct lwp *l, const struct sys_wait4_args *uap, register_t *retval) 712 { 713 /* { 714 syscallarg(int) pid; 715 syscallarg(int *) status; 716 syscallarg(int) options; 717 syscallarg(struct rusage *) rusage; 718 } */ 719 int status, error; 720 int was_zombie; 721 struct rusage ru; 722 int pid = SCARG(uap, pid); 723 724 error = do_sys_wait(l, &pid, &status, SCARG(uap, options), 725 SCARG(uap, rusage) != NULL ? &ru : NULL, &was_zombie); 726 727 retval[0] = pid; 728 if (pid == 0) 729 return error; 730 731 if (SCARG(uap, rusage)) 732 error = copyout(&ru, SCARG(uap, rusage), sizeof(ru)); 733 734 if (error == 0 && SCARG(uap, status)) 735 error = copyout(&status, SCARG(uap, status), sizeof(status)); 736 737 return error; 738 } 739 740 /* 741 * Scan list of child processes for a child process that has stopped or 742 * exited. Used by sys_wait4 and 'compat' equivalents. 743 * 744 * Must be called with the proclist_lock held, and may release 745 * while waiting. 746 */ 747 static int 748 find_stopped_child(struct proc *parent, pid_t pid, int options, 749 struct proc **child_p, int *status_p) 750 { 751 struct proc *child, *dead; 752 int error; 753 754 KASSERT(mutex_owned(&proclist_lock)); 755 756 if (options & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG) 757 && !(options & WOPTSCHECKED)) { 758 *child_p = NULL; 759 return EINVAL; 760 } 761 762 if (pid == 0 && !(options & WOPTSCHECKED)) 763 pid = -parent->p_pgid; 764 765 for (;;) { 766 error = ECHILD; 767 dead = NULL; 768 769 mutex_enter(&proclist_mutex); 770 LIST_FOREACH(child, &parent->p_children, p_sibling) { 771 if (pid >= 0) { 772 if (child->p_pid != pid) { 773 child = p_find(pid, PFIND_ZOMBIE | 774 PFIND_LOCKED); 775 if (child == NULL || 776 child->p_pptr != parent) { 777 child = NULL; 778 break; 779 } 780 } 781 } else if (pid != WAIT_ANY && child->p_pgid != -pid) { 782 /* Child not in correct pgrp */ 783 continue; 784 } 785 786 /* 787 * Wait for processes with p_exitsig != SIGCHLD 788 * processes only if WALTSIG is set; wait for 789 * processes with p_exitsig == SIGCHLD only 790 * if WALTSIG is clear. 791 */ 792 if (((options & WALLSIG) == 0) && 793 (options & WALTSIG ? child->p_exitsig == SIGCHLD 794 : P_EXITSIG(child) != SIGCHLD)){ 795 if (child->p_pid == pid) { 796 child = NULL; 797 break; 798 } 799 continue; 800 } 801 802 error = 0; 803 if ((options & WNOZOMBIE) == 0) { 804 if (child->p_stat == SZOMB) 805 break; 806 if (child->p_stat == SDEAD) { 807 /* 808 * We may occasionally arrive here 809 * after receiving a signal, but 810 * immediatley before the child 811 * process is zombified. The wait 812 * will be short, so avoid returning 813 * to userspace. 814 */ 815 dead = child; 816 } 817 } 818 819 if (child->p_stat == SSTOP && 820 child->p_waited == 0 && 821 (child->p_slflag & PSL_TRACED || 822 options & WUNTRACED)) { 823 if ((options & WNOWAIT) == 0) { 824 child->p_waited = 1; 825 parent->p_nstopchild--; 826 } 827 break; 828 } 829 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 830 child = NULL; 831 break; 832 } 833 } 834 835 if (child != NULL || error != 0 || 836 ((options & WNOHANG) != 0 && dead == NULL)) { 837 if (child != NULL) { 838 *status_p = child->p_xstat; 839 } 840 mutex_exit(&proclist_mutex); 841 *child_p = child; 842 return error; 843 } 844 845 /* 846 * Wait for another child process to stop. 847 */ 848 mutex_exit(&proclist_lock); 849 error = cv_wait_sig(&parent->p_waitcv, &proclist_mutex); 850 mutex_exit(&proclist_mutex); 851 mutex_enter(&proclist_lock); 852 853 if (error != 0) { 854 *child_p = NULL; 855 return error; 856 } 857 } 858 } 859 860 /* 861 * Free a process after parent has taken all the state info. Must be called 862 * with the proclist lock held, and will release before returning. 863 * 864 * *ru is returned to the caller, and must be freed by the caller. 865 */ 866 static void 867 proc_free(struct proc *p, struct rusage *ru) 868 { 869 struct proc *parent; 870 struct lwp *l; 871 ksiginfo_t ksi; 872 kauth_cred_t cred1, cred2; 873 uid_t uid; 874 875 KASSERT(mutex_owned(&proclist_lock)); 876 KASSERT(p->p_nlwps == 1); 877 KASSERT(p->p_nzlwps == 1); 878 KASSERT(p->p_nrlwps == 0); 879 KASSERT(p->p_stat == SZOMB); 880 881 /* 882 * If we got the child via ptrace(2) or procfs, and 883 * the parent is different (meaning the process was 884 * attached, rather than run as a child), then we need 885 * to give it back to the old parent, and send the 886 * parent the exit signal. The rest of the cleanup 887 * will be done when the old parent waits on the child. 888 */ 889 if ((p->p_slflag & PSL_TRACED) != 0) { 890 parent = p->p_pptr; 891 if (p->p_opptr != parent){ 892 mutex_enter(&p->p_smutex); 893 p->p_slflag &= ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); 894 mutex_exit(&p->p_smutex); 895 parent = p->p_opptr; 896 if (parent == NULL) 897 parent = initproc; 898 proc_reparent(p, parent); 899 p->p_opptr = NULL; 900 if (p->p_exitsig != 0) { 901 exit_psignal(p, parent, &ksi); 902 mutex_enter(&proclist_mutex); 903 kpsignal(parent, &ksi, NULL); 904 mutex_exit(&proclist_mutex); 905 } 906 KERNEL_LOCK(1, NULL); /* XXXSMP */ 907 cv_broadcast(&parent->p_waitcv); 908 KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */ 909 mutex_exit(&proclist_lock); 910 return; 911 } 912 } 913 914 /* 915 * Finally finished with old proc entry. Unlink it from its process 916 * group. 917 */ 918 leavepgrp(p); 919 920 parent = p->p_pptr; 921 sched_proc_exit(parent, p); 922 /* 923 * Add child times of exiting process onto its own times. 924 * This cannot be done any earlier else it might get done twice. 925 */ 926 ruadd(&p->p_stats->p_ru, &p->p_stats->p_cru); 927 ruadd(&parent->p_stats->p_cru, &p->p_stats->p_ru); 928 if (ru != NULL) 929 *ru = p->p_stats->p_ru; 930 p->p_xstat = 0; 931 932 /* 933 * At this point we are going to start freeing the final resources. 934 * If anyone tries to access the proc structure after here they will 935 * get a shock - bits are missing. Attempt to make it hard! We 936 * don't bother with any further locking past this point. 937 */ 938 mutex_enter(&proclist_mutex); 939 p->p_stat = SIDL; /* not even a zombie any more */ 940 LIST_REMOVE(p, p_list); /* off zombproc */ 941 parent = p->p_pptr; 942 p->p_pptr->p_nstopchild--; 943 mutex_exit(&proclist_mutex); 944 LIST_REMOVE(p, p_sibling); 945 946 /* 947 * Let pid be reallocated. 948 */ 949 proc_free_pid(p); 950 mutex_exit(&proclist_lock); 951 952 l = LIST_FIRST(&p->p_lwps); 953 954 /* 955 * Delay release until after lwp_free. 956 */ 957 cred2 = l->l_cred; 958 959 /* 960 * Free the last LWP's resources. 961 * 962 * lwp_free ensures the LWP is no longer running on another CPU. 963 */ 964 lwp_free(l, false, true); 965 966 /* 967 * Now no one except us can reach the process p. 968 */ 969 970 /* 971 * Decrement the count of procs running with this uid. 972 */ 973 cred1 = p->p_cred; 974 uid = kauth_cred_getuid(cred1); 975 (void)chgproccnt(uid, -1); 976 977 /* 978 * Release substructures. 979 */ 980 981 limfree(p->p_limit); 982 pstatsfree(p->p_stats); 983 kauth_cred_free(cred1); 984 kauth_cred_free(cred2); 985 986 /* 987 * Release reference to text vnode 988 */ 989 if (p->p_textvp) 990 vrele(p->p_textvp); 991 992 mutex_destroy(&p->p_auxlock); 993 mutex_destroy(&p->p_mutex); 994 mutex_destroy(&p->p_stmutex); 995 mutex_destroy(&p->p_smutex); 996 cv_destroy(&p->p_waitcv); 997 cv_destroy(&p->p_lwpcv); 998 rw_destroy(&p->p_reflock); 999 1000 proc_free_mem(p); 1001 } 1002 1003 /* 1004 * make process 'parent' the new parent of process 'child'. 1005 * 1006 * Must be called with proclist_lock lock held. 1007 */ 1008 void 1009 proc_reparent(struct proc *child, struct proc *parent) 1010 { 1011 1012 KASSERT(mutex_owned(&proclist_lock)); 1013 1014 if (child->p_pptr == parent) 1015 return; 1016 1017 mutex_enter(&proclist_mutex); 1018 if (child->p_stat == SZOMB || 1019 (child->p_stat == SSTOP && !child->p_waited)) { 1020 child->p_pptr->p_nstopchild--; 1021 parent->p_nstopchild++; 1022 } 1023 mutex_exit(&proclist_mutex); 1024 if (parent == initproc) 1025 child->p_exitsig = SIGCHLD; 1026 1027 LIST_REMOVE(child, p_sibling); 1028 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1029 child->p_pptr = parent; 1030 } 1031