1 /* $NetBSD: kern_exit.c,v 1.154 2005/12/11 12:24:29 christos 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 1.154 2005/12/11 12:24:29 christos 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> 116 117 #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 = p->p_ucred->cr_uid; 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 (void)acct_process(l); 318 #ifdef KTRACE 319 /* 320 * release trace file 321 */ 322 ktrderef(p); 323 #endif 324 #ifdef SYSTRACE 325 systrace_sys_exit(p); 326 #endif 327 /* 328 * If emulation has process exit hook, call it now. 329 */ 330 if (p->p_emul->e_proc_exit) 331 (*p->p_emul->e_proc_exit)(p); 332 333 /* 334 * Free the VM resources we're still holding on to. 335 * We must do this from a valid thread because doing 336 * so may block. This frees vmspace, which we don't 337 * need anymore. The only remaining lwp is the one 338 * we run at this moment, nothing runs in userland 339 * anymore. 340 */ 341 uvm_proc_exit(p); 342 343 /* 344 * Give machine-dependent code a chance to free any 345 * MD LWP resources while we can still block. This must be done 346 * before uvm_lwp_exit(), in case these resources are in the 347 * PCB. 348 * THIS IS LAST BLOCKING OPERATION. 349 */ 350 #ifndef __NO_CPU_LWP_FREE 351 cpu_lwp_free(l, 1); 352 #endif 353 354 pmap_deactivate(l); 355 356 /* 357 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 358 */ 359 360 /* 361 * Save exit status and final rusage info, adding in child rusage 362 * info and self times. 363 * In order to pick up the time for the current execution, we must 364 * do this before unlinking the lwp from l_list. 365 */ 366 p->p_xstat = rv; 367 *p->p_ru = p->p_stats->p_ru; 368 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 369 ruadd(p->p_ru, &p->p_stats->p_cru); 370 371 /* 372 * Notify interested parties of our demise. 373 */ 374 KNOTE(&p->p_klist, NOTE_EXIT); 375 376 #if PERFCTRS 377 /* 378 * Save final PMC information in parent process & clean up. 379 */ 380 if (PMC_ENABLED(p)) { 381 pmc_save_context(p); 382 pmc_accumulate(p->p_pptr, p); 383 pmc_process_exit(p); 384 } 385 #endif 386 387 s = proclist_lock_write(); 388 /* 389 * Reset p_opptr pointer of all former children which got 390 * traced by another process and were reparented. We reset 391 * it to NULL here; the trace detach code then reparents 392 * the child to initproc. We only check allproc list, since 393 * eventual former children on zombproc list won't reference 394 * p_opptr anymore. 395 */ 396 if (p->p_flag & P_CHTRACED) { 397 PROCLIST_FOREACH(q, &allproc) { 398 if (q->p_opptr == p) 399 q->p_opptr = NULL; 400 } 401 } 402 403 /* 404 * Give orphaned children to init(8). 405 */ 406 q = LIST_FIRST(&p->p_children); 407 if (q) /* only need this if any child is SZOMB */ 408 wakeup(initproc); 409 for (; q != NULL; q = nq) { 410 nq = LIST_NEXT(q, p_sibling); 411 412 /* 413 * Traced processes are killed since their existence 414 * means someone is screwing up. Since we reset the 415 * trace flags, the logic in sys_wait4() would not be 416 * triggered to reparent the process to its 417 * original parent, so we must do this here. 418 */ 419 if (q->p_flag & P_TRACED) { 420 if (q->p_opptr != q->p_pptr) { 421 struct proc *t = q->p_opptr; 422 proc_reparent(q, t ? t : initproc); 423 q->p_opptr = NULL; 424 } else 425 proc_reparent(q, initproc); 426 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 427 killproc(q, "orphaned traced process"); 428 } else { 429 proc_reparent(q, initproc); 430 } 431 } 432 433 /* 434 * Move proc from allproc to zombproc, it's now ready 435 * to be collected by parent. Remaining lwp resources 436 * will be freed in lwp_exit2() once we've switch to idle 437 * context. 438 * Changing the state to SZOMB stops it being found by pfind(). 439 */ 440 LIST_REMOVE(p, p_list); 441 LIST_INSERT_HEAD(&zombproc, p, p_list); 442 p->p_stat = SZOMB; 443 444 LIST_REMOVE(l, l_list); 445 LIST_REMOVE(l, l_sibling); 446 l->l_flag |= L_DETACHED; /* detached from proc too */ 447 l->l_stat = LSDEAD; 448 449 KASSERT(p->p_nrlwps == 1); 450 KASSERT(p->p_nlwps == 1); 451 p->p_nrlwps--; 452 p->p_nlwps--; 453 454 /* Put in front of parent's sibling list for parent to collect it */ 455 q = p->p_pptr; 456 q->p_nstopchild++; 457 if (LIST_FIRST(&q->p_children) != p) { 458 /* Put child where it can be found quickly */ 459 LIST_REMOVE(p, p_sibling); 460 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 461 } 462 463 /* 464 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 465 * flag set, notify init instead (and hope it will handle 466 * this situation). 467 */ 468 if (q->p_flag & (P_NOCLDWAIT|P_CLDSIGIGN)) { 469 proc_reparent(p, initproc); 470 471 /* 472 * If this was the last child of our parent, notify 473 * parent, so in case he was wait(2)ing, he will 474 * continue. 475 */ 476 if (LIST_FIRST(&q->p_children) == NULL) 477 wakeup(q); 478 } 479 480 /* 481 * Clear curlwp after we've done all operations 482 * that could block, and before tearing down the rest 483 * of the process state that might be used from clock, etc. 484 * Also, can't clear curlwp while we're still runnable, 485 * as we're not on a run queue (we are current, just not 486 * a proper proc any longer!). 487 * 488 * Other substructures are freed from wait(). 489 */ 490 curlwp = NULL; 491 492 /* Delay release until after dropping the proclist lock */ 493 plim = p->p_limit; 494 pstats = p->p_stats; 495 ps = p->p_sigacts; 496 497 p->p_limit = NULL; 498 p->p_stats = NULL; 499 p->p_sigacts = NULL; 500 501 /* Reload parent pointer, since p may have been reparented above */ 502 q = p->p_pptr; 503 504 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) { 505 exit_psignal(p, q, &ksi); 506 do_psignal = 1; 507 } 508 509 /* 510 * Once we release the proclist lock, we shouldn't touch the 511 * process structure anymore, since it's now on the zombie 512 * list and available for collection by the parent. 513 */ 514 proclist_unlock_write(s); 515 516 if (do_psignal) 517 kpsignal(q, &ksi, NULL); 518 519 /* Wake up the parent so it can get exit status. */ 520 wakeup(q); 521 522 /* Release substructures */ 523 sigactsfree(ps); 524 limfree(plim); 525 pstatsfree(pstats); 526 527 #ifdef DEBUG 528 /* Nothing should use the process link anymore */ 529 l->l_proc = NULL; 530 #endif 531 532 /* This process no longer needs to hold the kernel lock. */ 533 KERNEL_PROC_UNLOCK(l); 534 535 /* 536 * Finally, call machine-dependent code to switch to a new 537 * context (possibly the idle context). Once we are no longer 538 * using the dead lwp's stack, lwp_exit2() will be called 539 * to arrange for the resources to be released. 540 * 541 * Note that cpu_exit() will end with a call equivalent to 542 * cpu_switch(), finishing our execution (pun intended). 543 */ 544 545 uvmexp.swtch++; 546 cpu_exit(l); 547 } 548 549 void 550 exit_lwps(struct lwp *l) 551 { 552 struct proc *p; 553 struct lwp *l2; 554 struct sadata_vp *vp; 555 int s, error; 556 lwpid_t waited; 557 558 p = l->l_proc; 559 560 /* XXX SMP 561 * This would be the right place to IPI any LWPs running on 562 * other processors so that they can notice the userret exit hook. 563 */ 564 p->p_userret = lwp_exit_hook; 565 p->p_userret_arg = NULL; 566 567 if (p->p_sa) { 568 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 569 /* 570 * Make SA-cached LWPs normal process runnable 571 * LWPs so that they'll also self-destruct. 572 */ 573 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 574 p->p_pid, vp->savp_id)); 575 SCHED_LOCK(s); 576 while ((l2 = sa_getcachelwp(vp)) != 0) { 577 l2->l_priority = l2->l_usrpri; 578 setrunnable(l2); 579 DPRINTF(("%d ", l2->l_lid)); 580 } 581 SCHED_UNLOCK(s); 582 DPRINTF(("\n")); 583 584 /* 585 * Clear wokenq, the LWPs on the queue will 586 * run below. 587 */ 588 vp->savp_wokenq_head = NULL; 589 } 590 } 591 592 retry: 593 /* 594 * Interrupt LWPs in interruptable sleep, unsuspend suspended 595 * LWPs, make detached LWPs undetached (so we can wait for 596 * them) and then wait for everyone else to finish. 597 */ 598 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 599 l2->l_flag &= ~(L_DETACHED|L_SA); 600 601 SCHED_LOCK(s); 602 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 603 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 604 setrunnable(l2); 605 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 606 p->p_pid, l2->l_lid)); 607 } 608 SCHED_UNLOCK(s); 609 } 610 611 612 while (p->p_nlwps > 1) { 613 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 614 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 615 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 616 if (error == EDEADLK) { 617 /* 618 * LWPs can get suspended/slept behind us. 619 * (eg. sa_setwoken) 620 * kick them again and retry. 621 */ 622 goto retry; 623 } 624 if (error) 625 panic("exit_lwps: lwp_wait1 failed with error %d", 626 error); 627 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 628 } 629 630 p->p_userret = NULL; 631 } 632 633 /* Wrapper function for use in p_userret */ 634 static void 635 lwp_exit_hook(struct lwp *l, void *arg) 636 { 637 KERNEL_PROC_LOCK(l); 638 lwp_exit(l); 639 } 640 641 int 642 sys_wait4(struct lwp *l, void *v, register_t *retval) 643 { 644 struct sys_wait4_args /* { 645 syscallarg(int) pid; 646 syscallarg(int *) status; 647 syscallarg(int) options; 648 syscallarg(struct rusage *) rusage; 649 } */ *uap = v; 650 struct proc *child, *parent; 651 int status, error; 652 653 parent = l->l_proc; 654 655 if (SCARG(uap, pid) == 0) 656 SCARG(uap, pid) = -parent->p_pgid; 657 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 658 return (EINVAL); 659 660 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 661 &child); 662 if (error != 0) 663 return error; 664 if (child == NULL) { 665 *retval = 0; 666 return 0; 667 } 668 669 /* 670 * Collect child u-areas. 671 */ 672 uvm_uarea_drain(FALSE); 673 674 retval[0] = child->p_pid; 675 676 if (P_ZOMBIE(child)) { 677 if (SCARG(uap, status)) { 678 status = child->p_xstat; /* convert to int */ 679 error = copyout(&status, SCARG(uap, status), 680 sizeof(status)); 681 if (error) 682 return (error); 683 } 684 if (SCARG(uap, rusage)) { 685 error = copyout(child->p_ru, SCARG(uap, rusage), 686 sizeof(struct rusage)); 687 if (error) 688 return (error); 689 } 690 691 proc_free(child); 692 return 0; 693 } 694 695 /* child state must be SSTOP */ 696 if (SCARG(uap, status)) { 697 status = W_STOPCODE(child->p_xstat); 698 return copyout(&status, SCARG(uap, status), sizeof(status)); 699 } 700 return 0; 701 } 702 703 /* 704 * Scan list of child processes for a child process that has stopped or 705 * exited. Used by sys_wait4 and 'compat' equivalents. 706 */ 707 int 708 find_stopped_child(struct proc *parent, pid_t pid, int options, 709 struct proc **child_p) 710 { 711 struct proc *child; 712 int error; 713 714 for (;;) { 715 proclist_lock_read(); 716 error = ECHILD; 717 LIST_FOREACH(child, &parent->p_children, p_sibling) { 718 if (pid >= 0) { 719 if (child->p_pid != pid) { 720 child = p_find(pid, PFIND_ZOMBIE | 721 PFIND_LOCKED); 722 if (child == NULL 723 || child->p_pptr != parent) { 724 child = NULL; 725 break; 726 } 727 } 728 } else 729 if (pid != WAIT_ANY && child->p_pgid != -pid) 730 /* child not in correct pgrp */ 731 continue; 732 /* 733 * Wait for processes with p_exitsig != SIGCHLD 734 * processes only if WALTSIG is set; wait for 735 * processes with p_exitsig == SIGCHLD only 736 * if WALTSIG is clear. 737 */ 738 if (((options & WALLSIG) == 0) && 739 (options & WALTSIG ? child->p_exitsig == SIGCHLD 740 : P_EXITSIG(child) != SIGCHLD)){ 741 if (child->p_pid == pid) { 742 child = NULL; 743 break; 744 } 745 continue; 746 } 747 748 error = 0; 749 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 750 break; 751 752 if (child->p_stat == SSTOP && 753 (child->p_flag & P_WAITED) == 0 && 754 (child->p_flag & P_TRACED || options & WUNTRACED)) { 755 if ((options & WNOWAIT) == 0) { 756 child->p_flag |= P_WAITED; 757 parent->p_nstopchild--; 758 } 759 break; 760 } 761 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 762 child = NULL; 763 break; 764 } 765 } 766 proclist_unlock_read(); 767 if (child != NULL || error != 0 || options & WNOHANG) { 768 *child_p = child; 769 return error; 770 } 771 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 772 if (error != 0) 773 return error; 774 } 775 } 776 777 /* 778 * Free a process after parent has taken all the state info. 779 */ 780 void 781 proc_free(struct proc *p) 782 { 783 struct proc *parent = p->p_pptr; 784 ksiginfo_t ksi; 785 int s; 786 787 KASSERT(p->p_nlwps == 0); 788 KASSERT(p->p_nzlwps == 0); 789 KASSERT(p->p_nrlwps == 0); 790 KASSERT(LIST_EMPTY(&p->p_lwps)); 791 792 /* 793 * If we got the child via ptrace(2) or procfs, and 794 * the parent is different (meaning the process was 795 * attached, rather than run as a child), then we need 796 * to give it back to the old parent, and send the 797 * parent the exit signal. The rest of the cleanup 798 * will be done when the old parent waits on the child. 799 */ 800 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 801 parent = p->p_opptr; 802 if (parent == NULL) 803 parent = initproc; 804 proc_reparent(p, parent); 805 p->p_opptr = NULL; 806 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 807 if (p->p_exitsig != 0) { 808 exit_psignal(p, parent, &ksi); 809 kpsignal(parent, &ksi, NULL); 810 } 811 wakeup(parent); 812 return; 813 } 814 815 scheduler_wait_hook(parent, p); 816 p->p_xstat = 0; 817 818 ruadd(&parent->p_stats->p_cru, p->p_ru); 819 820 /* 821 * At this point we are going to start freeing the final resources. 822 * If anyone tries to access the proc structure after here they 823 * will get a shock - bits are missing. 824 * Attempt to make it hard! 825 */ 826 827 p->p_stat = SIDL; /* not even a zombie any more */ 828 829 pool_put(&rusage_pool, p->p_ru); 830 831 /* 832 * Finally finished with old proc entry. 833 * Unlink it from its process group and free it. 834 */ 835 leavepgrp(p); 836 837 s = proclist_lock_write(); 838 LIST_REMOVE(p, p_list); /* off zombproc */ 839 p->p_pptr->p_nstopchild--; 840 LIST_REMOVE(p, p_sibling); 841 proclist_unlock_write(s); 842 843 /* 844 * Decrement the count of procs running with this uid. 845 */ 846 (void)chgproccnt(p->p_cred->p_ruid, -1); 847 848 /* 849 * Free up credentials. 850 */ 851 if (--p->p_cred->p_refcnt == 0) { 852 crfree(p->p_cred->pc_ucred); 853 pool_put(&pcred_pool, p->p_cred); 854 } 855 856 /* 857 * Release reference to text vnode 858 */ 859 if (p->p_textvp) 860 vrele(p->p_textvp); 861 862 /* Release any SA state. */ 863 if (p->p_sa) 864 sa_release(p); 865 866 /* Free proc structure and let pid be reallocated */ 867 proc_free_mem(p); 868 } 869 870 /* 871 * make process 'parent' the new parent of process 'child'. 872 * 873 * Must be called with proclist_lock_write() held. 874 */ 875 void 876 proc_reparent(struct proc *child, struct proc *parent) 877 { 878 879 if (child->p_pptr == parent) 880 return; 881 882 if (child->p_stat == SZOMB 883 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 884 child->p_pptr->p_nstopchild--; 885 parent->p_nstopchild++; 886 } 887 if (parent == initproc) 888 child->p_exitsig = SIGCHLD; 889 890 LIST_REMOVE(child, p_sibling); 891 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 892 child->p_pptr = parent; 893 } 894