1 /* $NetBSD: kern_exit.c,v 1.159 2006/09/23 15:36:12 xtraeme 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 1.159 2006/09/23 15:36:12 xtraeme 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 * Free the VM resources we're still holding on to. 347 * We must do this from a valid thread because doing 348 * so may block. This frees vmspace, which we don't 349 * need anymore. The only remaining lwp is the one 350 * we run at this moment, nothing runs in userland 351 * anymore. 352 */ 353 uvm_proc_exit(p); 354 355 /* 356 * Give machine-dependent code a chance to free any 357 * MD LWP resources while we can still block. This must be done 358 * before uvm_lwp_exit(), in case these resources are in the 359 * PCB. 360 * THIS IS LAST BLOCKING OPERATION. 361 */ 362 #ifndef __NO_CPU_LWP_FREE 363 cpu_lwp_free(l, 1); 364 #endif 365 366 pmap_deactivate(l); 367 368 /* 369 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 370 */ 371 372 /* 373 * Save final rusage info, adding in child rusage info and self times. 374 * In order to pick up the time for the current execution, we must 375 * do this before unlinking the lwp from l_list. 376 */ 377 *p->p_ru = p->p_stats->p_ru; 378 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 379 ruadd(p->p_ru, &p->p_stats->p_cru); 380 381 /* 382 * Notify interested parties of our demise. 383 */ 384 KNOTE(&p->p_klist, NOTE_EXIT); 385 386 #if PERFCTRS 387 /* 388 * Save final PMC information in parent process & clean up. 389 */ 390 if (PMC_ENABLED(p)) { 391 pmc_save_context(p); 392 pmc_accumulate(p->p_pptr, p); 393 pmc_process_exit(p); 394 } 395 #endif 396 397 s = proclist_lock_write(); 398 /* 399 * Reset p_opptr pointer of all former children which got 400 * traced by another process and were reparented. We reset 401 * it to NULL here; the trace detach code then reparents 402 * the child to initproc. We only check allproc list, since 403 * eventual former children on zombproc list won't reference 404 * p_opptr anymore. 405 */ 406 if (p->p_flag & P_CHTRACED) { 407 PROCLIST_FOREACH(q, &allproc) { 408 if (q->p_opptr == p) 409 q->p_opptr = NULL; 410 } 411 } 412 413 /* 414 * Give orphaned children to init(8). 415 */ 416 q = LIST_FIRST(&p->p_children); 417 if (q) /* only need this if any child is SZOMB */ 418 wakeup(initproc); 419 for (; q != NULL; q = nq) { 420 nq = LIST_NEXT(q, p_sibling); 421 422 /* 423 * Traced processes are killed since their existence 424 * means someone is screwing up. Since we reset the 425 * trace flags, the logic in sys_wait4() would not be 426 * triggered to reparent the process to its 427 * original parent, so we must do this here. 428 */ 429 if (q->p_flag & P_TRACED) { 430 if (q->p_opptr != q->p_pptr) { 431 struct proc *t = q->p_opptr; 432 proc_reparent(q, t ? t : initproc); 433 q->p_opptr = NULL; 434 } else 435 proc_reparent(q, initproc); 436 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL); 437 killproc(q, "orphaned traced process"); 438 } else { 439 proc_reparent(q, initproc); 440 } 441 } 442 443 /* 444 * Move proc from allproc to zombproc, it's now ready 445 * to be collected by parent. Remaining lwp resources 446 * will be freed in lwp_exit2() once we've switch to idle 447 * context. 448 * Changing the state to SZOMB stops it being found by pfind(). 449 */ 450 LIST_REMOVE(p, p_list); 451 LIST_INSERT_HEAD(&zombproc, p, p_list); 452 p->p_stat = SZOMB; 453 454 LIST_REMOVE(l, l_list); 455 LIST_REMOVE(l, l_sibling); 456 l->l_flag |= L_DETACHED; /* detached from proc too */ 457 l->l_stat = LSDEAD; 458 459 KASSERT(p->p_nrlwps == 1); 460 KASSERT(p->p_nlwps == 1); 461 p->p_nrlwps--; 462 p->p_nlwps--; 463 464 /* Put in front of parent's sibling list for parent to collect it */ 465 q = p->p_pptr; 466 q->p_nstopchild++; 467 if (LIST_FIRST(&q->p_children) != p) { 468 /* Put child where it can be found quickly */ 469 LIST_REMOVE(p, p_sibling); 470 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 471 } 472 473 /* 474 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 475 * flag set, notify init instead (and hope it will handle 476 * this situation). 477 */ 478 if (q->p_flag & (P_NOCLDWAIT|P_CLDSIGIGN)) { 479 proc_reparent(p, initproc); 480 481 /* 482 * If this was the last child of our parent, notify 483 * parent, so in case he was wait(2)ing, he will 484 * continue. 485 */ 486 if (LIST_FIRST(&q->p_children) == NULL) 487 wakeup(q); 488 } 489 490 /* 491 * Clear curlwp after we've done all operations 492 * that could block, and before tearing down the rest 493 * of the process state that might be used from clock, etc. 494 * Also, can't clear curlwp while we're still runnable, 495 * as we're not on a run queue (we are current, just not 496 * a proper proc any longer!). 497 * 498 * Other substructures are freed from wait(). 499 */ 500 curlwp = NULL; 501 502 /* Delay release until after dropping the proclist lock */ 503 plim = p->p_limit; 504 pstats = p->p_stats; 505 ps = p->p_sigacts; 506 507 p->p_limit = NULL; 508 p->p_stats = NULL; 509 p->p_sigacts = NULL; 510 511 /* Reload parent pointer, since p may have been reparented above */ 512 q = p->p_pptr; 513 514 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) { 515 exit_psignal(p, q, &ksi); 516 do_psignal = 1; 517 } 518 519 /* 520 * Once we release the proclist lock, we shouldn't touch the 521 * process structure anymore, since it's now on the zombie 522 * list and available for collection by the parent. 523 */ 524 proclist_unlock_write(s); 525 526 if (do_psignal) 527 kpsignal(q, &ksi, NULL); 528 529 /* Wake up the parent so it can get exit status. */ 530 wakeup(q); 531 532 /* Release substructures */ 533 sigactsfree(ps); 534 limfree(plim); 535 pstatsfree(pstats); 536 537 /* Release cached credentials. */ 538 kauth_cred_free(l->l_cred); 539 540 #ifdef DEBUG 541 /* Nothing should use the process link anymore */ 542 l->l_proc = NULL; 543 #endif 544 545 /* This process no longer needs to hold the kernel lock. */ 546 KERNEL_PROC_UNLOCK(l); 547 548 /* 549 * Finally, call machine-dependent code to switch to a new 550 * context (possibly the idle context). Once we are no longer 551 * using the dead lwp's stack, lwp_exit2() will be called 552 * to arrange for the resources to be released. 553 * 554 * Note that cpu_exit() will end with a call equivalent to 555 * cpu_switch(), finishing our execution (pun intended). 556 */ 557 558 uvmexp.swtch++; 559 cpu_exit(l); 560 } 561 562 void 563 exit_lwps(struct lwp *l) 564 { 565 struct proc *p; 566 struct lwp *l2; 567 struct sadata_vp *vp; 568 int s, error; 569 lwpid_t waited; 570 571 p = l->l_proc; 572 573 /* XXX SMP 574 * This would be the right place to IPI any LWPs running on 575 * other processors so that they can notice the userret exit hook. 576 */ 577 p->p_userret = lwp_exit_hook; 578 p->p_userret_arg = NULL; 579 580 if (p->p_sa) { 581 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 582 /* 583 * Make SA-cached LWPs normal process runnable 584 * LWPs so that they'll also self-destruct. 585 */ 586 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 587 p->p_pid, vp->savp_id)); 588 SCHED_LOCK(s); 589 while ((l2 = sa_getcachelwp(vp)) != 0) { 590 l2->l_priority = l2->l_usrpri; 591 setrunnable(l2); 592 DPRINTF(("%d ", l2->l_lid)); 593 } 594 SCHED_UNLOCK(s); 595 DPRINTF(("\n")); 596 597 /* 598 * Clear wokenq, the LWPs on the queue will 599 * run below. 600 */ 601 vp->savp_wokenq_head = NULL; 602 } 603 } 604 605 retry: 606 /* 607 * Interrupt LWPs in interruptable sleep, unsuspend suspended 608 * LWPs, make detached LWPs undetached (so we can wait for 609 * them) and then wait for everyone else to finish. 610 */ 611 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 612 l2->l_flag &= ~(L_DETACHED|L_SA); 613 614 SCHED_LOCK(s); 615 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 616 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 617 setrunnable(l2); 618 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 619 p->p_pid, l2->l_lid)); 620 } 621 SCHED_UNLOCK(s); 622 } 623 624 625 while (p->p_nlwps > 1) { 626 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 627 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 628 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 629 if (error == EDEADLK) { 630 /* 631 * LWPs can get suspended/slept behind us. 632 * (eg. sa_setwoken) 633 * kick them again and retry. 634 */ 635 goto retry; 636 } 637 if (error) 638 panic("exit_lwps: lwp_wait1 failed with error %d", 639 error); 640 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 641 } 642 643 p->p_userret = NULL; 644 } 645 646 /* Wrapper function for use in p_userret */ 647 static void 648 lwp_exit_hook(struct lwp *l, void *arg) 649 { 650 KERNEL_PROC_LOCK(l); 651 lwp_exit(l); 652 } 653 654 int 655 sys_wait4(struct lwp *l, void *v, register_t *retval) 656 { 657 struct sys_wait4_args /* { 658 syscallarg(int) pid; 659 syscallarg(int *) status; 660 syscallarg(int) options; 661 syscallarg(struct rusage *) rusage; 662 } */ *uap = v; 663 struct proc *child, *parent; 664 int status, error; 665 666 parent = l->l_proc; 667 668 if (SCARG(uap, pid) == 0) 669 SCARG(uap, pid) = -parent->p_pgid; 670 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 671 return (EINVAL); 672 673 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 674 &child); 675 if (error != 0) 676 return error; 677 if (child == NULL) { 678 *retval = 0; 679 return 0; 680 } 681 682 /* 683 * Collect child u-areas. 684 */ 685 uvm_uarea_drain(FALSE); 686 687 retval[0] = child->p_pid; 688 689 if (P_ZOMBIE(child)) { 690 if (SCARG(uap, status)) { 691 status = child->p_xstat; /* convert to int */ 692 error = copyout(&status, SCARG(uap, status), 693 sizeof(status)); 694 if (error) 695 return (error); 696 } 697 if (SCARG(uap, rusage)) { 698 error = copyout(child->p_ru, SCARG(uap, rusage), 699 sizeof(struct rusage)); 700 if (error) 701 return (error); 702 } 703 704 proc_free(child); 705 return 0; 706 } 707 708 /* child state must be SSTOP */ 709 if (SCARG(uap, status)) { 710 status = W_STOPCODE(child->p_xstat); 711 return copyout(&status, SCARG(uap, status), sizeof(status)); 712 } 713 return 0; 714 } 715 716 /* 717 * Scan list of child processes for a child process that has stopped or 718 * exited. Used by sys_wait4 and 'compat' equivalents. 719 */ 720 int 721 find_stopped_child(struct proc *parent, pid_t pid, int options, 722 struct proc **child_p) 723 { 724 struct proc *child; 725 int error; 726 727 for (;;) { 728 proclist_lock_read(); 729 error = ECHILD; 730 LIST_FOREACH(child, &parent->p_children, p_sibling) { 731 if (pid >= 0) { 732 if (child->p_pid != pid) { 733 child = p_find(pid, PFIND_ZOMBIE | 734 PFIND_LOCKED); 735 if (child == NULL 736 || child->p_pptr != parent) { 737 child = NULL; 738 break; 739 } 740 } 741 } else 742 if (pid != WAIT_ANY && child->p_pgid != -pid) 743 /* child not in correct pgrp */ 744 continue; 745 /* 746 * Wait for processes with p_exitsig != SIGCHLD 747 * processes only if WALTSIG is set; wait for 748 * processes with p_exitsig == SIGCHLD only 749 * if WALTSIG is clear. 750 */ 751 if (((options & WALLSIG) == 0) && 752 (options & WALTSIG ? child->p_exitsig == SIGCHLD 753 : P_EXITSIG(child) != SIGCHLD)){ 754 if (child->p_pid == pid) { 755 child = NULL; 756 break; 757 } 758 continue; 759 } 760 761 error = 0; 762 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 763 break; 764 765 if (child->p_stat == SSTOP && 766 (child->p_flag & P_WAITED) == 0 && 767 (child->p_flag & P_TRACED || options & WUNTRACED)) { 768 if ((options & WNOWAIT) == 0) { 769 child->p_flag |= P_WAITED; 770 parent->p_nstopchild--; 771 } 772 break; 773 } 774 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 775 child = NULL; 776 break; 777 } 778 } 779 proclist_unlock_read(); 780 if (child != NULL || error != 0 || options & WNOHANG) { 781 *child_p = child; 782 return error; 783 } 784 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 785 if (error != 0) 786 return error; 787 } 788 } 789 790 /* 791 * Free a process after parent has taken all the state info. 792 */ 793 void 794 proc_free(struct proc *p) 795 { 796 struct proc *parent = p->p_pptr; 797 ksiginfo_t ksi; 798 int s; 799 800 KASSERT(p->p_nlwps == 0); 801 KASSERT(p->p_nzlwps == 0); 802 KASSERT(p->p_nrlwps == 0); 803 KASSERT(LIST_EMPTY(&p->p_lwps)); 804 805 /* 806 * If we got the child via ptrace(2) or procfs, and 807 * the parent is different (meaning the process was 808 * attached, rather than run as a child), then we need 809 * to give it back to the old parent, and send the 810 * parent the exit signal. The rest of the cleanup 811 * will be done when the old parent waits on the child. 812 */ 813 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 814 parent = p->p_opptr; 815 if (parent == NULL) 816 parent = initproc; 817 proc_reparent(p, parent); 818 p->p_opptr = NULL; 819 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL); 820 if (p->p_exitsig != 0) { 821 exit_psignal(p, parent, &ksi); 822 kpsignal(parent, &ksi, NULL); 823 } 824 wakeup(parent); 825 return; 826 } 827 828 scheduler_wait_hook(parent, p); 829 p->p_xstat = 0; 830 831 ruadd(&parent->p_stats->p_cru, p->p_ru); 832 833 /* 834 * At this point we are going to start freeing the final resources. 835 * If anyone tries to access the proc structure after here they 836 * will get a shock - bits are missing. 837 * Attempt to make it hard! 838 */ 839 840 p->p_stat = SIDL; /* not even a zombie any more */ 841 842 pool_put(&rusage_pool, p->p_ru); 843 844 /* 845 * Finally finished with old proc entry. 846 * Unlink it from its process group and free it. 847 */ 848 leavepgrp(p); 849 850 s = proclist_lock_write(); 851 LIST_REMOVE(p, p_list); /* off zombproc */ 852 p->p_pptr->p_nstopchild--; 853 LIST_REMOVE(p, p_sibling); 854 proclist_unlock_write(s); 855 856 /* 857 * Decrement the count of procs running with this uid. 858 */ 859 (void)chgproccnt(kauth_cred_getuid(p->p_cred), -1); 860 861 /* 862 * Free up credentials. 863 */ 864 kauth_cred_free(p->p_cred); 865 866 /* 867 * Release reference to text vnode 868 */ 869 if (p->p_textvp) 870 vrele(p->p_textvp); 871 872 /* Release any SA state. */ 873 if (p->p_sa) 874 sa_release(p); 875 876 /* Free proc structure and let pid be reallocated */ 877 proc_free_mem(p); 878 } 879 880 /* 881 * make process 'parent' the new parent of process 'child'. 882 * 883 * Must be called with proclist_lock_write() held. 884 */ 885 void 886 proc_reparent(struct proc *child, struct proc *parent) 887 { 888 889 if (child->p_pptr == parent) 890 return; 891 892 if (child->p_stat == SZOMB 893 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 894 child->p_pptr->p_nstopchild--; 895 parent->p_nstopchild++; 896 } 897 if (parent == initproc) 898 child->p_exitsig = SIGCHLD; 899 900 LIST_REMOVE(child, p_sibling); 901 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 902 child->p_pptr = parent; 903 } 904