1 /* $NetBSD: kern_exit.c,v 1.158 2006/08/23 19:49:09 manu 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 1.158 2006/08/23 19:49:09 manu 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/proc.h> 88 #include <sys/tty.h> 89 #include <sys/time.h> 90 #include <sys/resource.h> 91 #include <sys/kernel.h> 92 #include <sys/ktrace.h> 93 #include <sys/proc.h> 94 #include <sys/buf.h> 95 #include <sys/wait.h> 96 #include <sys/file.h> 97 #include <sys/vnode.h> 98 #include <sys/syslog.h> 99 #include <sys/malloc.h> 100 #include <sys/pool.h> 101 #include <sys/resourcevar.h> 102 #if defined(PERFCTRS) 103 #include <sys/pmc.h> 104 #endif 105 #include <sys/ptrace.h> 106 #include <sys/acct.h> 107 #include <sys/filedesc.h> 108 #include <sys/ras.h> 109 #include <sys/signalvar.h> 110 #include <sys/sched.h> 111 #include <sys/sa.h> 112 #include <sys/savar.h> 113 #include <sys/mount.h> 114 #include <sys/syscallargs.h> 115 #include <sys/systrace.h> 116 #include <sys/kauth.h> 117 118 #include <machine/cpu.h> 119 120 #include <uvm/uvm_extern.h> 121 122 #define DEBUG_EXIT 123 124 #ifdef DEBUG_EXIT 125 int debug_exit = 0; 126 #define DPRINTF(x) if (debug_exit) printf x 127 #else 128 #define DPRINTF(x) 129 #endif 130 131 static void lwp_exit_hook(struct lwp *, void *); 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 (void)memset(ksi, 0, sizeof(ksiginfo_t)); 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 */ 154 ksi->ksi_pid = p->p_pid; 155 ksi->ksi_uid = kauth_cred_geteuid(p->p_cred); 156 ksi->ksi_status = p->p_xstat; 157 /* XXX: is this still valid? */ 158 ksi->ksi_utime = p->p_ru->ru_utime.tv_sec; 159 ksi->ksi_stime = p->p_ru->ru_stime.tv_sec; 160 } 161 162 /* 163 * exit -- 164 * Death of process. 165 */ 166 int 167 sys_exit(struct lwp *l, void *v, register_t *retval) 168 { 169 struct sys_exit_args /* { 170 syscallarg(int) rval; 171 } */ *uap = v; 172 173 /* Don't call exit1() multiple times in the same process.*/ 174 if (l->l_proc->p_flag & P_WEXIT) 175 lwp_exit(l); 176 177 exit1(l, W_EXITCODE(SCARG(uap, rval), 0)); 178 /* NOTREACHED */ 179 return (0); 180 } 181 182 /* 183 * Exit: deallocate address space and other resources, change proc state 184 * to zombie, and unlink proc from allproc and parent's lists. Save exit 185 * status and rusage for wait(). Check for child processes and orphan them. 186 */ 187 void 188 exit1(struct lwp *l, int rv) 189 { 190 struct proc *p, *q, *nq; 191 int s, sa; 192 struct plimit *plim; 193 struct pstats *pstats; 194 struct sigacts *ps; 195 ksiginfo_t ksi; 196 int do_psignal = 0; 197 198 p = l->l_proc; 199 200 if (__predict_false(p == initproc)) 201 panic("init died (signal %d, exit %d)", 202 WTERMSIG(rv), WEXITSTATUS(rv)); 203 204 p->p_flag |= P_WEXIT; 205 if (p->p_flag & P_STOPEXIT) { 206 sigminusset(&contsigmask, &p->p_sigctx.ps_siglist); 207 SCHED_LOCK(s); 208 p->p_stat = SSTOP; 209 l->l_stat = LSSTOP; 210 p->p_nrlwps--; 211 mi_switch(l, NULL); 212 SCHED_ASSERT_UNLOCKED(); 213 splx(s); 214 } 215 216 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid)); 217 /* 218 * Disable scheduler activation upcalls. 219 * We're trying to get out of here. 220 */ 221 sa = 0; 222 if (p->p_sa != NULL) { 223 l->l_flag &= ~L_SA; 224 #if 0 225 p->p_flag &= ~P_SA; 226 #endif 227 sa = 1; 228 } 229 230 #ifdef PGINPROF 231 vmsizmon(); 232 #endif 233 if (p->p_flag & P_PROFIL) 234 stopprofclock(p); 235 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 236 /* 237 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 238 * wake up the parent early to avoid deadlock. 239 */ 240 if (p->p_flag & P_PPWAIT) { 241 p->p_flag &= ~P_PPWAIT; 242 wakeup(p->p_pptr); 243 } 244 sigfillset(&p->p_sigctx.ps_sigignore); 245 sigemptyset(&p->p_sigctx.ps_siglist); 246 p->p_sigctx.ps_sigcheck = 0; 247 timers_free(p, TIMERS_ALL); 248 249 if (sa || (p->p_nlwps > 1)) { 250 exit_lwps(l); 251 252 /* 253 * Collect thread u-areas. 254 */ 255 uvm_uarea_drain(FALSE); 256 } 257 258 #if defined(__HAVE_RAS) 259 ras_purgeall(p); 260 #endif 261 262 /* 263 * Close open files and release open-file table. 264 * This may block! 265 */ 266 fdfree(l); 267 cwdfree(p->p_cwdi); 268 p->p_cwdi = 0; 269 270 doexithooks(p); 271 272 if (SESS_LEADER(p)) { 273 struct session *sp = p->p_session; 274 struct tty *tp; 275 276 if (sp->s_ttyvp) { 277 /* 278 * Controlling process. 279 * Signal foreground pgrp, 280 * drain controlling terminal 281 * and revoke access to controlling terminal. 282 */ 283 tp = sp->s_ttyp; 284 s = spltty(); 285 TTY_LOCK(tp); 286 if (tp->t_session == sp) { 287 if (tp->t_pgrp) 288 pgsignal(tp->t_pgrp, SIGHUP, 1); 289 /* we can't guarantee the revoke will do this */ 290 tp->t_pgrp = NULL; 291 tp->t_session = NULL; 292 TTY_UNLOCK(tp); 293 splx(s); 294 SESSRELE(sp); 295 (void) ttywait(tp); 296 /* 297 * The tty could have been revoked 298 * if we blocked. 299 */ 300 if (sp->s_ttyvp) 301 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 302 } else { 303 TTY_UNLOCK(tp); 304 splx(s); 305 } 306 if (sp->s_ttyvp) 307 vrele(sp->s_ttyvp); 308 sp->s_ttyvp = NULL; 309 /* 310 * s_ttyp is not zero'd; we use this to indicate 311 * that the session once had a controlling terminal. 312 * (for logging and informational purposes) 313 */ 314 } 315 sp->s_leader = NULL; 316 } 317 fixjobc(p, p->p_pgrp, 0); 318 319 /* 320 * Collect accounting flags from the last remaining LWP (this one), 321 * and write out accounting data. 322 */ 323 p->p_acflag |= l->l_acflag; 324 (void)acct_process(l); 325 326 #ifdef KTRACE 327 /* 328 * Release trace file. 329 */ 330 ktrderef(p); 331 #endif 332 #ifdef SYSTRACE 333 systrace_sys_exit(p); 334 #endif 335 336 /* 337 * If emulation has process exit hook, call it now. 338 * Set the exit status now so that the exit hook has 339 * an opportunity to tweak it (COMPAT_LINUX requires 340 * this for thread group emulation) 341 */ 342 p->p_xstat = rv; 343 if (p->p_emul->e_proc_exit) 344 (*p->p_emul->e_proc_exit)(p); 345 346 /* 347 * Free the VM resources we're still holding on to. 348 * We must do this from a valid thread because doing 349 * so may block. This frees vmspace, which we don't 350 * need anymore. The only remaining lwp is the one 351 * we run at this moment, nothing runs in userland 352 * anymore. 353 */ 354 uvm_proc_exit(p); 355 356 /* 357 * Give machine-dependent code a chance to free any 358 * MD LWP resources while we can still block. This must be done 359 * before uvm_lwp_exit(), in case these resources are in the 360 * PCB. 361 * THIS IS LAST BLOCKING OPERATION. 362 */ 363 #ifndef __NO_CPU_LWP_FREE 364 cpu_lwp_free(l, 1); 365 #endif 366 367 pmap_deactivate(l); 368 369 /* 370 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 371 */ 372 373 /* 374 * Save final rusage info, adding in child rusage info and self times. 375 * In order to pick up the time for the current execution, we must 376 * do this before unlinking the lwp from l_list. 377 */ 378 *p->p_ru = p->p_stats->p_ru; 379 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 380 ruadd(p->p_ru, &p->p_stats->p_cru); 381 382 /* 383 * Notify interested parties of our demise. 384 */ 385 KNOTE(&p->p_klist, NOTE_EXIT); 386 387 #if PERFCTRS 388 /* 389 * Save final PMC information in parent process & clean up. 390 */ 391 if (PMC_ENABLED(p)) { 392 pmc_save_context(p); 393 pmc_accumulate(p->p_pptr, p); 394 pmc_process_exit(p); 395 } 396 #endif 397 398 s = proclist_lock_write(); 399 /* 400 * Reset p_opptr pointer of all former children which got 401 * traced by another process and were reparented. We reset 402 * it to NULL here; the trace detach code then reparents 403 * the child to initproc. We only check allproc list, since 404 * eventual former children on zombproc list won't reference 405 * p_opptr anymore. 406 */ 407 if (p->p_flag & P_CHTRACED) { 408 PROCLIST_FOREACH(q, &allproc) { 409 if (q->p_opptr == p) 410 q->p_opptr = NULL; 411 } 412 } 413 414 /* 415 * Give orphaned children to init(8). 416 */ 417 q = LIST_FIRST(&p->p_children); 418 if (q) /* only need this if any child is SZOMB */ 419 wakeup(initproc); 420 for (; q != NULL; q = nq) { 421 nq = LIST_NEXT(q, p_sibling); 422 423 /* 424 * Traced processes are killed since their existence 425 * means someone is screwing up. Since we reset the 426 * trace flags, the logic in sys_wait4() would not be 427 * triggered to reparent the process to its 428 * original parent, so we must do this here. 429 */ 430 if (q->p_flag & P_TRACED) { 431 if (q->p_opptr != q->p_pptr) { 432 struct proc *t = q->p_opptr; 433 proc_reparent(q, t ? t : initproc); 434 q->p_opptr = NULL; 435 } else 436 proc_reparent(q, initproc); 437 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL); 438 killproc(q, "orphaned traced process"); 439 } else { 440 proc_reparent(q, initproc); 441 } 442 } 443 444 /* 445 * Move proc from allproc to zombproc, it's now ready 446 * to be collected by parent. Remaining lwp resources 447 * will be freed in lwp_exit2() once we've switch to idle 448 * context. 449 * Changing the state to SZOMB stops it being found by pfind(). 450 */ 451 LIST_REMOVE(p, p_list); 452 LIST_INSERT_HEAD(&zombproc, p, p_list); 453 p->p_stat = SZOMB; 454 455 LIST_REMOVE(l, l_list); 456 LIST_REMOVE(l, l_sibling); 457 l->l_flag |= L_DETACHED; /* detached from proc too */ 458 l->l_stat = LSDEAD; 459 460 KASSERT(p->p_nrlwps == 1); 461 KASSERT(p->p_nlwps == 1); 462 p->p_nrlwps--; 463 p->p_nlwps--; 464 465 /* Put in front of parent's sibling list for parent to collect it */ 466 q = p->p_pptr; 467 q->p_nstopchild++; 468 if (LIST_FIRST(&q->p_children) != p) { 469 /* Put child where it can be found quickly */ 470 LIST_REMOVE(p, p_sibling); 471 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 472 } 473 474 /* 475 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 476 * flag set, notify init instead (and hope it will handle 477 * this situation). 478 */ 479 if (q->p_flag & (P_NOCLDWAIT|P_CLDSIGIGN)) { 480 proc_reparent(p, initproc); 481 482 /* 483 * If this was the last child of our parent, notify 484 * parent, so in case he was wait(2)ing, he will 485 * continue. 486 */ 487 if (LIST_FIRST(&q->p_children) == NULL) 488 wakeup(q); 489 } 490 491 /* 492 * Clear curlwp after we've done all operations 493 * that could block, and before tearing down the rest 494 * of the process state that might be used from clock, etc. 495 * Also, can't clear curlwp while we're still runnable, 496 * as we're not on a run queue (we are current, just not 497 * a proper proc any longer!). 498 * 499 * Other substructures are freed from wait(). 500 */ 501 curlwp = NULL; 502 503 /* Delay release until after dropping the proclist lock */ 504 plim = p->p_limit; 505 pstats = p->p_stats; 506 ps = p->p_sigacts; 507 508 p->p_limit = NULL; 509 p->p_stats = NULL; 510 p->p_sigacts = NULL; 511 512 /* Reload parent pointer, since p may have been reparented above */ 513 q = p->p_pptr; 514 515 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) { 516 exit_psignal(p, q, &ksi); 517 do_psignal = 1; 518 } 519 520 /* 521 * Once we release the proclist lock, we shouldn't touch the 522 * process structure anymore, since it's now on the zombie 523 * list and available for collection by the parent. 524 */ 525 proclist_unlock_write(s); 526 527 if (do_psignal) 528 kpsignal(q, &ksi, NULL); 529 530 /* Wake up the parent so it can get exit status. */ 531 wakeup(q); 532 533 /* Release substructures */ 534 sigactsfree(ps); 535 limfree(plim); 536 pstatsfree(pstats); 537 538 /* Release cached credentials. */ 539 kauth_cred_free(l->l_cred); 540 541 #ifdef DEBUG 542 /* Nothing should use the process link anymore */ 543 l->l_proc = NULL; 544 #endif 545 546 /* This process no longer needs to hold the kernel lock. */ 547 KERNEL_PROC_UNLOCK(l); 548 549 /* 550 * Finally, call machine-dependent code to switch to a new 551 * context (possibly the idle context). Once we are no longer 552 * using the dead lwp's stack, lwp_exit2() will be called 553 * to arrange for the resources to be released. 554 * 555 * Note that cpu_exit() will end with a call equivalent to 556 * cpu_switch(), finishing our execution (pun intended). 557 */ 558 559 uvmexp.swtch++; 560 cpu_exit(l); 561 } 562 563 void 564 exit_lwps(struct lwp *l) 565 { 566 struct proc *p; 567 struct lwp *l2; 568 struct sadata_vp *vp; 569 int s, error; 570 lwpid_t waited; 571 572 p = l->l_proc; 573 574 /* XXX SMP 575 * This would be the right place to IPI any LWPs running on 576 * other processors so that they can notice the userret exit hook. 577 */ 578 p->p_userret = lwp_exit_hook; 579 p->p_userret_arg = NULL; 580 581 if (p->p_sa) { 582 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 583 /* 584 * Make SA-cached LWPs normal process runnable 585 * LWPs so that they'll also self-destruct. 586 */ 587 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 588 p->p_pid, vp->savp_id)); 589 SCHED_LOCK(s); 590 while ((l2 = sa_getcachelwp(vp)) != 0) { 591 l2->l_priority = l2->l_usrpri; 592 setrunnable(l2); 593 DPRINTF(("%d ", l2->l_lid)); 594 } 595 SCHED_UNLOCK(s); 596 DPRINTF(("\n")); 597 598 /* 599 * Clear wokenq, the LWPs on the queue will 600 * run below. 601 */ 602 vp->savp_wokenq_head = NULL; 603 } 604 } 605 606 retry: 607 /* 608 * Interrupt LWPs in interruptable sleep, unsuspend suspended 609 * LWPs, make detached LWPs undetached (so we can wait for 610 * them) and then wait for everyone else to finish. 611 */ 612 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 613 l2->l_flag &= ~(L_DETACHED|L_SA); 614 615 SCHED_LOCK(s); 616 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 617 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 618 setrunnable(l2); 619 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 620 p->p_pid, l2->l_lid)); 621 } 622 SCHED_UNLOCK(s); 623 } 624 625 626 while (p->p_nlwps > 1) { 627 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 628 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 629 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 630 if (error == EDEADLK) { 631 /* 632 * LWPs can get suspended/slept behind us. 633 * (eg. sa_setwoken) 634 * kick them again and retry. 635 */ 636 goto retry; 637 } 638 if (error) 639 panic("exit_lwps: lwp_wait1 failed with error %d", 640 error); 641 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 642 } 643 644 p->p_userret = NULL; 645 } 646 647 /* Wrapper function for use in p_userret */ 648 static void 649 lwp_exit_hook(struct lwp *l, void *arg) 650 { 651 KERNEL_PROC_LOCK(l); 652 lwp_exit(l); 653 } 654 655 int 656 sys_wait4(struct lwp *l, void *v, register_t *retval) 657 { 658 struct sys_wait4_args /* { 659 syscallarg(int) pid; 660 syscallarg(int *) status; 661 syscallarg(int) options; 662 syscallarg(struct rusage *) rusage; 663 } */ *uap = v; 664 struct proc *child, *parent; 665 int status, error; 666 667 parent = l->l_proc; 668 669 if (SCARG(uap, pid) == 0) 670 SCARG(uap, pid) = -parent->p_pgid; 671 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 672 return (EINVAL); 673 674 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 675 &child); 676 if (error != 0) 677 return error; 678 if (child == NULL) { 679 *retval = 0; 680 return 0; 681 } 682 683 /* 684 * Collect child u-areas. 685 */ 686 uvm_uarea_drain(FALSE); 687 688 retval[0] = child->p_pid; 689 690 if (P_ZOMBIE(child)) { 691 if (SCARG(uap, status)) { 692 status = child->p_xstat; /* convert to int */ 693 error = copyout(&status, SCARG(uap, status), 694 sizeof(status)); 695 if (error) 696 return (error); 697 } 698 if (SCARG(uap, rusage)) { 699 error = copyout(child->p_ru, SCARG(uap, rusage), 700 sizeof(struct rusage)); 701 if (error) 702 return (error); 703 } 704 705 proc_free(child); 706 return 0; 707 } 708 709 /* child state must be SSTOP */ 710 if (SCARG(uap, status)) { 711 status = W_STOPCODE(child->p_xstat); 712 return copyout(&status, SCARG(uap, status), sizeof(status)); 713 } 714 return 0; 715 } 716 717 /* 718 * Scan list of child processes for a child process that has stopped or 719 * exited. Used by sys_wait4 and 'compat' equivalents. 720 */ 721 int 722 find_stopped_child(struct proc *parent, pid_t pid, int options, 723 struct proc **child_p) 724 { 725 struct proc *child; 726 int error; 727 728 for (;;) { 729 proclist_lock_read(); 730 error = ECHILD; 731 LIST_FOREACH(child, &parent->p_children, p_sibling) { 732 if (pid >= 0) { 733 if (child->p_pid != pid) { 734 child = p_find(pid, PFIND_ZOMBIE | 735 PFIND_LOCKED); 736 if (child == NULL 737 || child->p_pptr != parent) { 738 child = NULL; 739 break; 740 } 741 } 742 } else 743 if (pid != WAIT_ANY && child->p_pgid != -pid) 744 /* child not in correct pgrp */ 745 continue; 746 /* 747 * Wait for processes with p_exitsig != SIGCHLD 748 * processes only if WALTSIG is set; wait for 749 * processes with p_exitsig == SIGCHLD only 750 * if WALTSIG is clear. 751 */ 752 if (((options & WALLSIG) == 0) && 753 (options & WALTSIG ? child->p_exitsig == SIGCHLD 754 : P_EXITSIG(child) != SIGCHLD)){ 755 if (child->p_pid == pid) { 756 child = NULL; 757 break; 758 } 759 continue; 760 } 761 762 error = 0; 763 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 764 break; 765 766 if (child->p_stat == SSTOP && 767 (child->p_flag & P_WAITED) == 0 && 768 (child->p_flag & P_TRACED || options & WUNTRACED)) { 769 if ((options & WNOWAIT) == 0) { 770 child->p_flag |= P_WAITED; 771 parent->p_nstopchild--; 772 } 773 break; 774 } 775 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 776 child = NULL; 777 break; 778 } 779 } 780 proclist_unlock_read(); 781 if (child != NULL || error != 0 || options & WNOHANG) { 782 *child_p = child; 783 return error; 784 } 785 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 786 if (error != 0) 787 return error; 788 } 789 } 790 791 /* 792 * Free a process after parent has taken all the state info. 793 */ 794 void 795 proc_free(struct proc *p) 796 { 797 struct proc *parent = p->p_pptr; 798 ksiginfo_t ksi; 799 int s; 800 801 KASSERT(p->p_nlwps == 0); 802 KASSERT(p->p_nzlwps == 0); 803 KASSERT(p->p_nrlwps == 0); 804 KASSERT(LIST_EMPTY(&p->p_lwps)); 805 806 /* 807 * If we got the child via ptrace(2) or procfs, and 808 * the parent is different (meaning the process was 809 * attached, rather than run as a child), then we need 810 * to give it back to the old parent, and send the 811 * parent the exit signal. The rest of the cleanup 812 * will be done when the old parent waits on the child. 813 */ 814 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 815 parent = p->p_opptr; 816 if (parent == NULL) 817 parent = initproc; 818 proc_reparent(p, parent); 819 p->p_opptr = NULL; 820 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL); 821 if (p->p_exitsig != 0) { 822 exit_psignal(p, parent, &ksi); 823 kpsignal(parent, &ksi, NULL); 824 } 825 wakeup(parent); 826 return; 827 } 828 829 scheduler_wait_hook(parent, p); 830 p->p_xstat = 0; 831 832 ruadd(&parent->p_stats->p_cru, p->p_ru); 833 834 /* 835 * At this point we are going to start freeing the final resources. 836 * If anyone tries to access the proc structure after here they 837 * will get a shock - bits are missing. 838 * Attempt to make it hard! 839 */ 840 841 p->p_stat = SIDL; /* not even a zombie any more */ 842 843 pool_put(&rusage_pool, p->p_ru); 844 845 /* 846 * Finally finished with old proc entry. 847 * Unlink it from its process group and free it. 848 */ 849 leavepgrp(p); 850 851 s = proclist_lock_write(); 852 LIST_REMOVE(p, p_list); /* off zombproc */ 853 p->p_pptr->p_nstopchild--; 854 LIST_REMOVE(p, p_sibling); 855 proclist_unlock_write(s); 856 857 /* 858 * Decrement the count of procs running with this uid. 859 */ 860 (void)chgproccnt(kauth_cred_getuid(p->p_cred), -1); 861 862 /* 863 * Free up credentials. 864 */ 865 kauth_cred_free(p->p_cred); 866 867 /* 868 * Release reference to text vnode 869 */ 870 if (p->p_textvp) 871 vrele(p->p_textvp); 872 873 /* Release any SA state. */ 874 if (p->p_sa) 875 sa_release(p); 876 877 /* Free proc structure and let pid be reallocated */ 878 proc_free_mem(p); 879 } 880 881 /* 882 * make process 'parent' the new parent of process 'child'. 883 * 884 * Must be called with proclist_lock_write() held. 885 */ 886 void 887 proc_reparent(struct proc *child, struct proc *parent) 888 { 889 890 if (child->p_pptr == parent) 891 return; 892 893 if (child->p_stat == SZOMB 894 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 895 child->p_pptr->p_nstopchild--; 896 parent->p_nstopchild++; 897 } 898 if (parent == initproc) 899 child->p_exitsig = SIGCHLD; 900 901 LIST_REMOVE(child, p_sibling); 902 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 903 child->p_pptr = parent; 904 } 905