1 /* $NetBSD: kern_exit.c,v 1.162 2006/11/01 10:17:58 yamt Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 1999 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. 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 1.162 2006/11/01 10:17:58 yamt Exp $"); 78 79 #include "opt_ktrace.h" 80 #include "opt_perfctrs.h" 81 #include "opt_systrace.h" 82 #include "opt_sysv.h" 83 84 #include <sys/param.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/ktrace.h> 92 #include <sys/proc.h> 93 #include <sys/buf.h> 94 #include <sys/wait.h> 95 #include <sys/file.h> 96 #include <sys/vnode.h> 97 #include <sys/syslog.h> 98 #include <sys/malloc.h> 99 #include <sys/pool.h> 100 #include <sys/resourcevar.h> 101 #if defined(PERFCTRS) 102 #include <sys/pmc.h> 103 #endif 104 #include <sys/ptrace.h> 105 #include <sys/acct.h> 106 #include <sys/filedesc.h> 107 #include <sys/ras.h> 108 #include <sys/signalvar.h> 109 #include <sys/sched.h> 110 #include <sys/sa.h> 111 #include <sys/savar.h> 112 #include <sys/mount.h> 113 #include <sys/syscallargs.h> 114 #include <sys/systrace.h> 115 #include <sys/kauth.h> 116 117 #include <machine/cpu.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 void lwp_exit_hook(struct lwp *, void *); 131 132 /* 133 * Fill in the appropriate signal information, and signal the parent. 134 */ 135 static void 136 exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi) 137 { 138 139 (void)memset(ksi, 0, sizeof(ksiginfo_t)); 140 if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) { 141 if (WIFSIGNALED(p->p_xstat)) { 142 if (WCOREDUMP(p->p_xstat)) 143 ksi->ksi_code = CLD_DUMPED; 144 else 145 ksi->ksi_code = CLD_KILLED; 146 } else { 147 ksi->ksi_code = CLD_EXITED; 148 } 149 } 150 /* 151 * we fill those in, even for non-SIGCHLD. 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_ru->ru_utime.tv_sec; 158 ksi->ksi_stime = p->p_ru->ru_stime.tv_sec; 159 } 160 161 /* 162 * exit -- 163 * Death of process. 164 */ 165 int 166 sys_exit(struct lwp *l, void *v, register_t *retval) 167 { 168 struct sys_exit_args /* { 169 syscallarg(int) rval; 170 } */ *uap = v; 171 172 /* Don't call exit1() multiple times in the same process.*/ 173 if (l->l_proc->p_flag & P_WEXIT) 174 lwp_exit(l); 175 176 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 void 187 exit1(struct lwp *l, int rv) 188 { 189 struct proc *p, *q, *nq; 190 int s, sa; 191 struct plimit *plim; 192 struct pstats *pstats; 193 struct sigacts *ps; 194 ksiginfo_t ksi; 195 int do_psignal = 0; 196 197 p = l->l_proc; 198 199 if (__predict_false(p == initproc)) 200 panic("init died (signal %d, exit %d)", 201 WTERMSIG(rv), WEXITSTATUS(rv)); 202 203 p->p_flag |= P_WEXIT; 204 if (p->p_flag & P_STOPEXIT) { 205 sigminusset(&contsigmask, &p->p_sigctx.ps_siglist); 206 SCHED_LOCK(s); 207 p->p_stat = SSTOP; 208 l->l_stat = LSSTOP; 209 p->p_nrlwps--; 210 mi_switch(l, NULL); 211 SCHED_ASSERT_UNLOCKED(); 212 splx(s); 213 } 214 215 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid)); 216 /* 217 * Disable scheduler activation upcalls. 218 * We're trying to get out of here. 219 */ 220 sa = 0; 221 if (p->p_sa != NULL) { 222 l->l_flag &= ~L_SA; 223 #if 0 224 p->p_flag &= ~P_SA; 225 #endif 226 sa = 1; 227 } 228 229 #ifdef PGINPROF 230 vmsizmon(); 231 #endif 232 if (p->p_flag & P_PROFIL) 233 stopprofclock(p); 234 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 235 /* 236 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 237 * wake up the parent early to avoid deadlock. 238 */ 239 if (p->p_flag & P_PPWAIT) { 240 p->p_flag &= ~P_PPWAIT; 241 wakeup(p->p_pptr); 242 } 243 sigfillset(&p->p_sigctx.ps_sigignore); 244 sigemptyset(&p->p_sigctx.ps_siglist); 245 p->p_sigctx.ps_sigcheck = 0; 246 timers_free(p, TIMERS_ALL); 247 248 if (sa || (p->p_nlwps > 1)) { 249 exit_lwps(l); 250 251 /* 252 * Collect thread u-areas. 253 */ 254 uvm_uarea_drain(FALSE); 255 } 256 257 #if defined(__HAVE_RAS) 258 ras_purgeall(p); 259 #endif 260 261 /* 262 * Close open files and release open-file table. 263 * This may block! 264 */ 265 fdfree(l); 266 cwdfree(p->p_cwdi); 267 p->p_cwdi = 0; 268 269 doexithooks(p); 270 271 if (SESS_LEADER(p)) { 272 struct session *sp = p->p_session; 273 struct tty *tp; 274 275 if (sp->s_ttyvp) { 276 /* 277 * Controlling process. 278 * Signal foreground pgrp, 279 * drain controlling terminal 280 * and revoke access to controlling terminal. 281 */ 282 tp = sp->s_ttyp; 283 s = spltty(); 284 TTY_LOCK(tp); 285 if (tp->t_session == sp) { 286 if (tp->t_pgrp) 287 pgsignal(tp->t_pgrp, SIGHUP, 1); 288 /* we can't guarantee the revoke will do this */ 289 tp->t_pgrp = NULL; 290 tp->t_session = NULL; 291 TTY_UNLOCK(tp); 292 splx(s); 293 SESSRELE(sp); 294 (void) ttywait(tp); 295 /* 296 * The tty could have been revoked 297 * if we blocked. 298 */ 299 if (sp->s_ttyvp) 300 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 301 } else { 302 TTY_UNLOCK(tp); 303 splx(s); 304 } 305 if (sp->s_ttyvp) 306 vrele(sp->s_ttyvp); 307 sp->s_ttyvp = NULL; 308 /* 309 * s_ttyp is not zero'd; we use this to indicate 310 * that the session once had a controlling terminal. 311 * (for logging and informational purposes) 312 */ 313 } 314 sp->s_leader = NULL; 315 } 316 fixjobc(p, p->p_pgrp, 0); 317 318 /* 319 * Collect accounting flags from the last remaining LWP (this one), 320 * and write out accounting data. 321 */ 322 p->p_acflag |= l->l_acflag; 323 (void)acct_process(l); 324 325 #ifdef KTRACE 326 /* 327 * Release trace file. 328 */ 329 ktrderef(p); 330 #endif 331 #ifdef SYSTRACE 332 systrace_sys_exit(p); 333 #endif 334 335 /* 336 * If emulation has process exit hook, call it now. 337 * Set the exit status now so that the exit hook has 338 * an opportunity to tweak it (COMPAT_LINUX requires 339 * this for thread group emulation) 340 */ 341 p->p_xstat = rv; 342 if (p->p_emul->e_proc_exit) 343 (*p->p_emul->e_proc_exit)(p); 344 345 /* 346 * Finalize the last LWP's specificdata, as well as the 347 * specificdata for the proc itself. 348 */ 349 lwp_finispecific(l); 350 proc_finispecific(p); 351 352 /* 353 * Free the VM resources we're still holding on to. 354 * We must do this from a valid thread because doing 355 * so may block. This frees vmspace, which we don't 356 * need anymore. The only remaining lwp is the one 357 * we run at this moment, nothing runs in userland 358 * anymore. 359 */ 360 uvm_proc_exit(p); 361 362 /* 363 * Give machine-dependent code a chance to free any 364 * MD LWP resources while we can still block. This must be done 365 * before uvm_lwp_exit(), in case these resources are in the 366 * PCB. 367 * THIS IS LAST BLOCKING OPERATION. 368 */ 369 #ifndef __NO_CPU_LWP_FREE 370 cpu_lwp_free(l, 1); 371 #endif 372 373 pmap_deactivate(l); 374 375 /* 376 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 377 */ 378 379 /* 380 * Save final rusage info, adding in child rusage info and self times. 381 * In order to pick up the time for the current execution, we must 382 * do this before unlinking the lwp from l_list. 383 */ 384 *p->p_ru = p->p_stats->p_ru; 385 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 386 ruadd(p->p_ru, &p->p_stats->p_cru); 387 388 /* 389 * Notify interested parties of our demise. 390 */ 391 KNOTE(&p->p_klist, NOTE_EXIT); 392 393 #if PERFCTRS 394 /* 395 * Save final PMC information in parent process & clean up. 396 */ 397 if (PMC_ENABLED(p)) { 398 pmc_save_context(p); 399 pmc_accumulate(p->p_pptr, p); 400 pmc_process_exit(p); 401 } 402 #endif 403 404 s = proclist_lock_write(); 405 /* 406 * Reset p_opptr pointer of all former children which got 407 * traced by another process and were reparented. We reset 408 * it to NULL here; the trace detach code then reparents 409 * the child to initproc. We only check allproc list, since 410 * eventual former children on zombproc list won't reference 411 * p_opptr anymore. 412 */ 413 if (p->p_flag & P_CHTRACED) { 414 PROCLIST_FOREACH(q, &allproc) { 415 if (q->p_opptr == p) 416 q->p_opptr = NULL; 417 } 418 } 419 420 /* 421 * Give orphaned children to init(8). 422 */ 423 q = LIST_FIRST(&p->p_children); 424 if (q) /* only need this if any child is SZOMB */ 425 wakeup(initproc); 426 for (; q != NULL; q = nq) { 427 nq = LIST_NEXT(q, p_sibling); 428 429 /* 430 * Traced processes are killed since their existence 431 * means someone is screwing up. Since we reset the 432 * trace flags, the logic in sys_wait4() would not be 433 * triggered to reparent the process to its 434 * original parent, so we must do this here. 435 */ 436 if (q->p_flag & P_TRACED) { 437 if (q->p_opptr != q->p_pptr) { 438 struct proc *t = q->p_opptr; 439 proc_reparent(q, t ? t : initproc); 440 q->p_opptr = NULL; 441 } else 442 proc_reparent(q, initproc); 443 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL); 444 killproc(q, "orphaned traced process"); 445 } else { 446 proc_reparent(q, initproc); 447 } 448 } 449 450 /* 451 * Move proc from allproc to zombproc, it's now ready 452 * to be collected by parent. Remaining lwp resources 453 * will be freed in lwp_exit2() once we've switch to idle 454 * context. 455 * Changing the state to SZOMB stops it being found by pfind(). 456 */ 457 LIST_REMOVE(p, p_list); 458 LIST_INSERT_HEAD(&zombproc, p, p_list); 459 p->p_stat = SZOMB; 460 461 LIST_REMOVE(l, l_list); 462 LIST_REMOVE(l, l_sibling); 463 l->l_flag |= L_DETACHED; /* detached from proc too */ 464 l->l_stat = LSDEAD; 465 466 KASSERT(p->p_nrlwps == 1); 467 KASSERT(p->p_nlwps == 1); 468 p->p_nrlwps--; 469 p->p_nlwps--; 470 471 /* Put in front of parent's sibling list for parent to collect it */ 472 q = p->p_pptr; 473 q->p_nstopchild++; 474 if (LIST_FIRST(&q->p_children) != p) { 475 /* Put child where it can be found quickly */ 476 LIST_REMOVE(p, p_sibling); 477 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 478 } 479 480 /* 481 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 482 * flag set, notify init instead (and hope it will handle 483 * this situation). 484 */ 485 if (q->p_flag & (P_NOCLDWAIT|P_CLDSIGIGN)) { 486 proc_reparent(p, initproc); 487 488 /* 489 * If this was the last child of our parent, notify 490 * parent, so in case he was wait(2)ing, he will 491 * continue. 492 */ 493 if (LIST_FIRST(&q->p_children) == NULL) 494 wakeup(q); 495 } 496 497 /* 498 * Clear curlwp after we've done all operations 499 * that could block, and before tearing down the rest 500 * of the process state that might be used from clock, etc. 501 * Also, can't clear curlwp while we're still runnable, 502 * as we're not on a run queue (we are current, just not 503 * a proper proc any longer!). 504 * 505 * Other substructures are freed from wait(). 506 */ 507 curlwp = NULL; 508 509 /* Delay release until after dropping the proclist lock */ 510 plim = p->p_limit; 511 pstats = p->p_stats; 512 ps = p->p_sigacts; 513 514 p->p_limit = NULL; 515 p->p_stats = NULL; 516 p->p_sigacts = NULL; 517 518 /* Reload parent pointer, since p may have been reparented above */ 519 q = p->p_pptr; 520 521 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) { 522 exit_psignal(p, q, &ksi); 523 do_psignal = 1; 524 } 525 526 /* 527 * Once we release the proclist lock, we shouldn't touch the 528 * process structure anymore, since it's now on the zombie 529 * list and available for collection by the parent. 530 */ 531 proclist_unlock_write(s); 532 533 if (do_psignal) 534 kpsignal(q, &ksi, NULL); 535 536 /* Wake up the parent so it can get exit status. */ 537 wakeup(q); 538 539 /* Release substructures */ 540 sigactsfree(ps); 541 limfree(plim); 542 pstatsfree(pstats); 543 544 /* Release cached credentials. */ 545 kauth_cred_free(l->l_cred); 546 547 #ifdef DEBUG 548 /* Nothing should use the process link anymore */ 549 l->l_proc = NULL; 550 #endif 551 552 /* This process no longer needs to hold the kernel lock. */ 553 KERNEL_PROC_UNLOCK(l); 554 555 /* 556 * Finally, call machine-dependent code to switch to a new 557 * context (possibly the idle context). Once we are no longer 558 * using the dead lwp's stack, lwp_exit2() will be called 559 * to arrange for the resources to be released. 560 * 561 * Note that cpu_exit() will end with a call equivalent to 562 * cpu_switch(), finishing our execution (pun intended). 563 */ 564 565 uvmexp.swtch++; 566 cpu_exit(l); 567 } 568 569 void 570 exit_lwps(struct lwp *l) 571 { 572 struct proc *p; 573 struct lwp *l2; 574 struct sadata_vp *vp; 575 int s, error; 576 lwpid_t waited; 577 578 p = l->l_proc; 579 580 /* XXX SMP 581 * This would be the right place to IPI any LWPs running on 582 * other processors so that they can notice the userret exit hook. 583 */ 584 p->p_userret = lwp_exit_hook; 585 p->p_userret_arg = NULL; 586 587 if (p->p_sa) { 588 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 589 /* 590 * Make SA-cached LWPs normal process runnable 591 * LWPs so that they'll also self-destruct. 592 */ 593 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 594 p->p_pid, vp->savp_id)); 595 SCHED_LOCK(s); 596 while ((l2 = sa_getcachelwp(vp)) != 0) { 597 l2->l_priority = l2->l_usrpri; 598 setrunnable(l2); 599 DPRINTF(("%d ", l2->l_lid)); 600 } 601 SCHED_UNLOCK(s); 602 DPRINTF(("\n")); 603 604 /* 605 * Clear wokenq, the LWPs on the queue will 606 * run below. 607 */ 608 vp->savp_wokenq_head = NULL; 609 } 610 } 611 612 retry: 613 /* 614 * Interrupt LWPs in interruptable sleep, unsuspend suspended 615 * LWPs, make detached LWPs undetached (so we can wait for 616 * them) and then wait for everyone else to finish. 617 */ 618 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 619 l2->l_flag &= ~(L_DETACHED|L_SA); 620 621 SCHED_LOCK(s); 622 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 623 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 624 setrunnable(l2); 625 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 626 p->p_pid, l2->l_lid)); 627 } 628 SCHED_UNLOCK(s); 629 } 630 631 632 while (p->p_nlwps > 1) { 633 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 634 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 635 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 636 if (error == EDEADLK) { 637 /* 638 * LWPs can get suspended/slept behind us. 639 * (eg. sa_setwoken) 640 * kick them again and retry. 641 */ 642 goto retry; 643 } 644 if (error) 645 panic("exit_lwps: lwp_wait1 failed with error %d", 646 error); 647 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 648 } 649 650 p->p_userret = NULL; 651 } 652 653 /* Wrapper function for use in p_userret */ 654 static void 655 lwp_exit_hook(struct lwp *l, void *arg) 656 { 657 658 KERNEL_PROC_LOCK(l); 659 lwp_exit(l); 660 } 661 662 int 663 sys_wait4(struct lwp *l, void *v, register_t *retval) 664 { 665 struct sys_wait4_args /* { 666 syscallarg(int) pid; 667 syscallarg(int *) status; 668 syscallarg(int) options; 669 syscallarg(struct rusage *) rusage; 670 } */ *uap = v; 671 struct proc *child, *parent; 672 int status, error; 673 674 parent = l->l_proc; 675 676 if (SCARG(uap, pid) == 0) 677 SCARG(uap, pid) = -parent->p_pgid; 678 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 679 return (EINVAL); 680 681 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 682 &child); 683 if (error != 0) 684 return error; 685 if (child == NULL) { 686 *retval = 0; 687 return 0; 688 } 689 690 /* 691 * Collect child u-areas. 692 */ 693 uvm_uarea_drain(FALSE); 694 695 retval[0] = child->p_pid; 696 697 if (P_ZOMBIE(child)) { 698 if (SCARG(uap, status)) { 699 status = child->p_xstat; /* convert to int */ 700 error = copyout(&status, SCARG(uap, status), 701 sizeof(status)); 702 if (error) 703 return (error); 704 } 705 if (SCARG(uap, rusage)) { 706 error = copyout(child->p_ru, SCARG(uap, rusage), 707 sizeof(struct rusage)); 708 if (error) 709 return (error); 710 } 711 712 proc_free(child); 713 return 0; 714 } 715 716 /* child state must be SSTOP */ 717 if (SCARG(uap, status)) { 718 status = W_STOPCODE(child->p_xstat); 719 return copyout(&status, SCARG(uap, status), sizeof(status)); 720 } 721 return 0; 722 } 723 724 /* 725 * Scan list of child processes for a child process that has stopped or 726 * exited. Used by sys_wait4 and 'compat' equivalents. 727 */ 728 int 729 find_stopped_child(struct proc *parent, pid_t pid, int options, 730 struct proc **child_p) 731 { 732 struct proc *child; 733 int error; 734 735 for (;;) { 736 proclist_lock_read(); 737 error = ECHILD; 738 LIST_FOREACH(child, &parent->p_children, p_sibling) { 739 if (pid >= 0) { 740 if (child->p_pid != pid) { 741 child = p_find(pid, PFIND_ZOMBIE | 742 PFIND_LOCKED); 743 if (child == NULL 744 || child->p_pptr != parent) { 745 child = NULL; 746 break; 747 } 748 } 749 } else 750 if (pid != WAIT_ANY && child->p_pgid != -pid) 751 /* child not in correct pgrp */ 752 continue; 753 /* 754 * Wait for processes with p_exitsig != SIGCHLD 755 * processes only if WALTSIG is set; wait for 756 * processes with p_exitsig == SIGCHLD only 757 * if WALTSIG is clear. 758 */ 759 if (((options & WALLSIG) == 0) && 760 (options & WALTSIG ? child->p_exitsig == SIGCHLD 761 : P_EXITSIG(child) != SIGCHLD)){ 762 if (child->p_pid == pid) { 763 child = NULL; 764 break; 765 } 766 continue; 767 } 768 769 error = 0; 770 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 771 break; 772 773 if (child->p_stat == SSTOP && 774 (child->p_flag & P_WAITED) == 0 && 775 (child->p_flag & P_TRACED || options & WUNTRACED)) { 776 if ((options & WNOWAIT) == 0) { 777 child->p_flag |= P_WAITED; 778 parent->p_nstopchild--; 779 } 780 break; 781 } 782 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 783 child = NULL; 784 break; 785 } 786 } 787 proclist_unlock_read(); 788 if (child != NULL || error != 0 || options & WNOHANG) { 789 *child_p = child; 790 return error; 791 } 792 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 793 if (error != 0) 794 return error; 795 } 796 } 797 798 /* 799 * Free a process after parent has taken all the state info. 800 */ 801 void 802 proc_free(struct proc *p) 803 { 804 struct proc *parent = p->p_pptr; 805 ksiginfo_t ksi; 806 int s; 807 808 KASSERT(p->p_nlwps == 0); 809 KASSERT(p->p_nzlwps == 0); 810 KASSERT(p->p_nrlwps == 0); 811 KASSERT(LIST_EMPTY(&p->p_lwps)); 812 813 /* 814 * If we got the child via ptrace(2) or procfs, and 815 * the parent is different (meaning the process was 816 * attached, rather than run as a child), then we need 817 * to give it back to the old parent, and send the 818 * parent the exit signal. The rest of the cleanup 819 * will be done when the old parent waits on the child. 820 */ 821 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 822 parent = p->p_opptr; 823 if (parent == NULL) 824 parent = initproc; 825 proc_reparent(p, parent); 826 p->p_opptr = NULL; 827 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL); 828 if (p->p_exitsig != 0) { 829 exit_psignal(p, parent, &ksi); 830 kpsignal(parent, &ksi, NULL); 831 } 832 wakeup(parent); 833 return; 834 } 835 836 scheduler_wait_hook(parent, p); 837 p->p_xstat = 0; 838 839 ruadd(&parent->p_stats->p_cru, p->p_ru); 840 841 /* 842 * At this point we are going to start freeing the final resources. 843 * If anyone tries to access the proc structure after here they 844 * will get a shock - bits are missing. 845 * Attempt to make it hard! 846 */ 847 848 p->p_stat = SIDL; /* not even a zombie any more */ 849 850 pool_put(&rusage_pool, p->p_ru); 851 852 /* 853 * Finally finished with old proc entry. 854 * Unlink it from its process group and free it. 855 */ 856 leavepgrp(p); 857 858 s = proclist_lock_write(); 859 LIST_REMOVE(p, p_list); /* off zombproc */ 860 p->p_pptr->p_nstopchild--; 861 LIST_REMOVE(p, p_sibling); 862 proclist_unlock_write(s); 863 864 /* 865 * Decrement the count of procs running with this uid. 866 */ 867 (void)chgproccnt(kauth_cred_getuid(p->p_cred), -1); 868 869 /* 870 * Free up credentials. 871 */ 872 kauth_cred_free(p->p_cred); 873 874 /* 875 * Release reference to text vnode 876 */ 877 if (p->p_textvp) 878 vrele(p->p_textvp); 879 880 /* Release any SA state. */ 881 if (p->p_sa) 882 sa_release(p); 883 884 /* Free proc structure and let pid be reallocated */ 885 proc_free_mem(p); 886 } 887 888 /* 889 * make process 'parent' the new parent of process 'child'. 890 * 891 * Must be called with proclist_lock_write() held. 892 */ 893 void 894 proc_reparent(struct proc *child, struct proc *parent) 895 { 896 897 if (child->p_pptr == parent) 898 return; 899 900 if (child->p_stat == SZOMB 901 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 902 child->p_pptr->p_nstopchild--; 903 parent->p_nstopchild++; 904 } 905 if (parent == initproc) 906 child->p_exitsig = SIGCHLD; 907 908 LIST_REMOVE(child, p_sibling); 909 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 910 child->p_pptr = parent; 911 } 912