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sys/kern/kern_exit.c
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1 /* $NetBSD: kern_exit.c,v 1.145.2.3 2005/10/04 14:16:42 tron 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 1.145.2.3 2005/10/04 14:16:42 tron 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 int s; 206 207 sigminusset(&contsigmask, &p->p_sigctx.ps_siglist); 208 SCHED_LOCK(s); 209 p->p_stat = SSTOP; 210 l->l_stat = LSSTOP; 211 p->p_nrlwps--; 212 mi_switch(l, NULL); 213 SCHED_ASSERT_UNLOCKED(); 214 splx(s); 215 } 216 217 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid)); 218 /* 219 * Disable scheduler activation upcalls. 220 * We're trying to get out of here. 221 */ 222 sa = 0; 223 if (p->p_sa != NULL) { 224 l->l_flag &= ~L_SA; 225 #if 0 226 p->p_flag &= ~P_SA; 227 #endif 228 sa = 1; 229 } 230 231 #ifdef PGINPROF 232 vmsizmon(); 233 #endif 234 if (p->p_flag & P_PROFIL) 235 stopprofclock(p); 236 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 237 /* 238 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 239 * wake up the parent early to avoid deadlock. 240 */ 241 if (p->p_flag & P_PPWAIT) { 242 p->p_flag &= ~P_PPWAIT; 243 wakeup(p->p_pptr); 244 } 245 sigfillset(&p->p_sigctx.ps_sigignore); 246 sigemptyset(&p->p_sigctx.ps_siglist); 247 p->p_sigctx.ps_sigcheck = 0; 248 timers_free(p, TIMERS_ALL); 249 250 if (sa || (p->p_nlwps > 1)) { 251 exit_lwps(l); 252 253 /* 254 * Collect thread u-areas. 255 */ 256 uvm_uarea_drain(FALSE); 257 } 258 259 #if defined(__HAVE_RAS) 260 ras_purgeall(p); 261 #endif 262 263 /* 264 * Close open files and release open-file table. 265 * This may block! 266 */ 267 fdfree(p); 268 cwdfree(p->p_cwdi); 269 p->p_cwdi = 0; 270 271 doexithooks(p); 272 273 if (SESS_LEADER(p)) { 274 struct session *sp = p->p_session; 275 struct tty *tp; 276 277 if (sp->s_ttyvp) { 278 int s; 279 /* 280 * Controlling process. 281 * Signal foreground pgrp, 282 * drain controlling terminal 283 * and revoke access to controlling terminal. 284 */ 285 tp = sp->s_ttyp; 286 s = spltty(); 287 TTY_LOCK(tp); 288 if (tp->t_session == sp) { 289 if (tp->t_pgrp) 290 pgsignal(tp->t_pgrp, SIGHUP, 1); 291 /* we can't guarantee the revoke will do this */ 292 tp->t_pgrp = NULL; 293 tp->t_session = NULL; 294 TTY_UNLOCK(tp); 295 splx(s); 296 SESSRELE(sp); 297 (void) ttywait(tp); 298 /* 299 * The tty could have been revoked 300 * if we blocked. 301 */ 302 if (sp->s_ttyvp) 303 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 304 } else { 305 TTY_UNLOCK(tp); 306 splx(s); 307 } 308 if (sp->s_ttyvp) 309 vrele(sp->s_ttyvp); 310 sp->s_ttyvp = NULL; 311 /* 312 * s_ttyp is not zero'd; we use this to indicate 313 * that the session once had a controlling terminal. 314 * (for logging and informational purposes) 315 */ 316 } 317 sp->s_leader = NULL; 318 } 319 fixjobc(p, p->p_pgrp, 0); 320 (void)acct_process(p); 321 #ifdef KTRACE 322 /* 323 * release trace file 324 */ 325 ktrderef(p); 326 #endif 327 #ifdef SYSTRACE 328 systrace_sys_exit(p); 329 #endif 330 /* 331 * If emulation has process exit hook, call it now. 332 */ 333 if (p->p_emul->e_proc_exit) 334 (*p->p_emul->e_proc_exit)(p); 335 336 /* 337 * Free the VM resources we're still holding on to. 338 * We must do this from a valid thread because doing 339 * so may block. This frees vmspace, which we don't 340 * need anymore. The only remaining lwp is the one 341 * we run at this moment, nothing runs in userland 342 * anymore. 343 */ 344 uvm_proc_exit(p); 345 346 /* 347 * Give machine-dependent code a chance to free any 348 * MD LWP resources while we can still block. This must be done 349 * before uvm_lwp_exit(), in case these resources are in the 350 * PCB. 351 * THIS IS LAST BLOCKING OPERATION. 352 */ 353 #ifndef __NO_CPU_LWP_FREE 354 cpu_lwp_free(l, 1); 355 #endif 356 357 pmap_deactivate(l); 358 359 /* 360 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 361 */ 362 363 /* 364 * Save exit status and final rusage info, adding in child rusage 365 * info and self times. 366 * In order to pick up the time for the current execution, we must 367 * do this before unlinking the lwp from l_list. 368 */ 369 p->p_xstat = rv; 370 *p->p_ru = p->p_stats->p_ru; 371 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 372 ruadd(p->p_ru, &p->p_stats->p_cru); 373 374 /* 375 * Notify interested parties of our demise. 376 */ 377 KNOTE(&p->p_klist, NOTE_EXIT); 378 379 #if PERFCTRS 380 /* 381 * Save final PMC information in parent process & clean up. 382 */ 383 if (PMC_ENABLED(p)) { 384 pmc_save_context(p); 385 pmc_accumulate(p->p_pptr, p); 386 pmc_process_exit(p); 387 } 388 #endif 389 390 s = proclist_lock_write(); 391 /* 392 * Reset p_opptr pointer of all former children which got 393 * traced by another process and were reparented. We reset 394 * it to NULL here; the trace detach code then reparents 395 * the child to initproc. We only check allproc list, since 396 * eventual former children on zombproc list won't reference 397 * p_opptr anymore. 398 */ 399 if (p->p_flag & P_CHTRACED) { 400 PROCLIST_FOREACH(q, &allproc) { 401 if (q->p_opptr == p) 402 q->p_opptr = NULL; 403 } 404 } 405 406 /* 407 * Give orphaned children to init(8). 408 */ 409 q = LIST_FIRST(&p->p_children); 410 if (q) /* only need this if any child is SZOMB */ 411 wakeup(initproc); 412 for (; q != NULL; q = nq) { 413 nq = LIST_NEXT(q, p_sibling); 414 415 /* 416 * Traced processes are killed since their existence 417 * means someone is screwing up. Since we reset the 418 * trace flags, the logic in sys_wait4() would not be 419 * triggered to reparent the process to its 420 * original parent, so we must do this here. 421 */ 422 if (q->p_flag & P_TRACED) { 423 if (q->p_opptr != q->p_pptr) { 424 struct proc *t = q->p_opptr; 425 proc_reparent(q, t ? t : initproc); 426 q->p_opptr = NULL; 427 } else 428 proc_reparent(q, initproc); 429 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 430 psignal(q, SIGKILL); 431 } else { 432 proc_reparent(q, initproc); 433 } 434 } 435 436 /* 437 * Move proc from allproc to zombproc, it's now ready 438 * to be collected by parent. Remaining lwp resources 439 * will be freed in lwp_exit2() once we've switch to idle 440 * context. 441 * Changing the state to SZOMB stops it being found by pfind(). 442 */ 443 LIST_REMOVE(p, p_list); 444 LIST_INSERT_HEAD(&zombproc, p, p_list); 445 p->p_stat = SZOMB; 446 447 LIST_REMOVE(l, l_list); 448 LIST_REMOVE(l, l_sibling); 449 l->l_flag |= L_DETACHED|L_PROCEXIT; /* detached from proc too */ 450 l->l_stat = LSDEAD; 451 452 KASSERT(p->p_nrlwps == 1); 453 KASSERT(p->p_nlwps == 1); 454 p->p_nrlwps--; 455 p->p_nlwps--; 456 457 /* Put in front of parent's sibling list for parent to collect it */ 458 q = p->p_pptr; 459 q->p_nstopchild++; 460 if (LIST_FIRST(&q->p_children) != p) { 461 /* Put child where it can be found quickly */ 462 LIST_REMOVE(p, p_sibling); 463 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 464 } 465 466 /* 467 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 468 * flag set, notify init instead (and hope it will handle 469 * this situation). 470 */ 471 if (q->p_flag & P_NOCLDWAIT) { 472 proc_reparent(p, initproc); 473 474 /* 475 * If this was the last child of our parent, notify 476 * parent, so in case he was wait(2)ing, he will 477 * continue. 478 */ 479 if (LIST_FIRST(&q->p_children) == NULL) 480 wakeup(q); 481 } 482 483 /* 484 * Clear curlwp after we've done all operations 485 * that could block, and before tearing down the rest 486 * of the process state that might be used from clock, etc. 487 * Also, can't clear curlwp while we're still runnable, 488 * as we're not on a run queue (we are current, just not 489 * a proper proc any longer!). 490 * 491 * Other substructures are freed from wait(). 492 */ 493 curlwp = NULL; 494 495 /* Delay release until after dropping the proclist lock */ 496 plim = p->p_limit; 497 pstats = p->p_stats; 498 ps = p->p_sigacts; 499 500 p->p_limit = NULL; 501 p->p_stats = NULL; 502 p->p_sigacts = NULL; 503 504 /* Reload parent pointer, since p may have been reparented above */ 505 q = p->p_pptr; 506 507 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) { 508 exit_psignal(p, q, &ksi); 509 do_psignal = 1; 510 } 511 512 /* 513 * Once we release the proclist lock, we shouldn't touch the 514 * process structure anymore, since it's now on the zombie 515 * list and available for collection by the parent. 516 */ 517 proclist_unlock_write(s); 518 519 if (do_psignal) 520 kpsignal(q, &ksi, NULL); 521 522 /* Wake up the parent so it can get exit status. */ 523 wakeup(q); 524 525 /* Release substructures */ 526 sigactsfree(ps); 527 limfree(plim); 528 pstatsfree(pstats); 529 530 #ifdef DEBUG 531 /* Nothing should use the process link anymore */ 532 l->l_proc = NULL; 533 #endif 534 535 /* This process no longer needs to hold the kernel lock. */ 536 KERNEL_PROC_UNLOCK(l); 537 538 /* 539 * Finally, call machine-dependent code to switch to a new 540 * context (possibly the idle context). Once we are no longer 541 * using the dead lwp's stack, lwp_exit2() will be called 542 * to arrange for the resources to be released. 543 * 544 * Note that cpu_exit() will end with a call equivalent to 545 * cpu_switch(), finishing our execution (pun intended). 546 */ 547 548 uvmexp.swtch++; 549 cpu_exit(l); 550 } 551 552 void 553 exit_lwps(struct lwp *l) 554 { 555 struct proc *p; 556 struct lwp *l2; 557 struct sadata_vp *vp; 558 int s, error; 559 lwpid_t waited; 560 561 p = l->l_proc; 562 563 /* XXX SMP 564 * This would be the right place to IPI any LWPs running on 565 * other processors so that they can notice the userret exit hook. 566 */ 567 p->p_userret = lwp_exit_hook; 568 p->p_userret_arg = NULL; 569 570 if (p->p_sa) { 571 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 572 /* 573 * Make SA-cached LWPs normal process runnable 574 * LWPs so that they'll also self-destruct. 575 */ 576 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 577 p->p_pid, vp->savp_id)); 578 SCHED_LOCK(s); 579 while ((l2 = sa_getcachelwp(vp)) != 0) { 580 l2->l_priority = l2->l_usrpri; 581 setrunnable(l2); 582 DPRINTF(("%d ", l2->l_lid)); 583 } 584 SCHED_UNLOCK(s); 585 DPRINTF(("\n")); 586 587 /* 588 * Clear wokenq, the LWPs on the queue will 589 * run below. 590 */ 591 vp->savp_wokenq_head = NULL; 592 } 593 } 594 595 retry: 596 /* 597 * Interrupt LWPs in interruptable sleep, unsuspend suspended 598 * LWPs, make detached LWPs undetached (so we can wait for 599 * them) and then wait for everyone else to finish. 600 */ 601 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 602 l2->l_flag &= ~(L_DETACHED|L_SA); 603 604 SCHED_LOCK(s); 605 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 606 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 607 setrunnable(l2); 608 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 609 p->p_pid, l2->l_lid)); 610 } 611 SCHED_UNLOCK(s); 612 } 613 614 615 while (p->p_nlwps > 1) { 616 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 617 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 618 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 619 if (error == EDEADLK) { 620 /* 621 * LWPs can get suspended/slept behind us. 622 * (eg. sa_setwoken) 623 * kick them again and retry. 624 */ 625 goto retry; 626 } 627 if (error) 628 panic("exit_lwps: lwp_wait1 failed with error %d\n", 629 error); 630 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 631 } 632 633 p->p_userret = NULL; 634 } 635 636 /* Wrapper function for use in p_userret */ 637 static void 638 lwp_exit_hook(struct lwp *l, void *arg) 639 { 640 KERNEL_PROC_LOCK(l); 641 lwp_exit(l); 642 } 643 644 int 645 sys_wait4(struct lwp *l, void *v, register_t *retval) 646 { 647 struct sys_wait4_args /* { 648 syscallarg(int) pid; 649 syscallarg(int *) status; 650 syscallarg(int) options; 651 syscallarg(struct rusage *) rusage; 652 } */ *uap = v; 653 struct proc *child, *parent; 654 int status, error; 655 656 parent = l->l_proc; 657 658 if (SCARG(uap, pid) == 0) 659 SCARG(uap, pid) = -parent->p_pgid; 660 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 661 return (EINVAL); 662 663 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 664 &child); 665 if (error != 0) 666 return error; 667 if (child == NULL) { 668 *retval = 0; 669 return 0; 670 } 671 672 /* 673 * Collect child u-areas. 674 */ 675 uvm_uarea_drain(FALSE); 676 677 retval[0] = child->p_pid; 678 679 if (P_ZOMBIE(child)) { 680 if (SCARG(uap, status)) { 681 status = child->p_xstat; /* convert to int */ 682 error = copyout(&status, SCARG(uap, status), 683 sizeof(status)); 684 if (error) 685 return (error); 686 } 687 if (SCARG(uap, rusage)) { 688 error = copyout(child->p_ru, SCARG(uap, rusage), 689 sizeof(struct rusage)); 690 if (error) 691 return (error); 692 } 693 694 proc_free(child); 695 return 0; 696 } 697 698 /* child state must be SSTOP */ 699 if (SCARG(uap, status)) { 700 status = W_STOPCODE(child->p_xstat); 701 return copyout(&status, SCARG(uap, status), sizeof(status)); 702 } 703 return 0; 704 } 705 706 /* 707 * Scan list of child processes for a child process that has stopped or 708 * exited. Used by sys_wait4 and 'compat' equivalents. 709 */ 710 int 711 find_stopped_child(struct proc *parent, pid_t pid, int options, 712 struct proc **child_p) 713 { 714 struct proc *child; 715 int error; 716 717 for (;;) { 718 proclist_lock_read(); 719 error = ECHILD; 720 LIST_FOREACH(child, &parent->p_children, p_sibling) { 721 if (pid >= 0) { 722 if (child->p_pid != pid) { 723 child = p_find(pid, PFIND_ZOMBIE | 724 PFIND_LOCKED); 725 if (child == NULL 726 || child->p_pptr != parent) { 727 child = NULL; 728 break; 729 } 730 } 731 } else 732 if (pid != WAIT_ANY && child->p_pgid != -pid) 733 /* child not in correct pgrp */ 734 continue; 735 /* 736 * Wait for processes with p_exitsig != SIGCHLD 737 * processes only if WALTSIG is set; wait for 738 * processes with p_exitsig == SIGCHLD only 739 * if WALTSIG is clear. 740 */ 741 if (((options & WALLSIG) == 0) && 742 (options & WALTSIG ? child->p_exitsig == SIGCHLD 743 : P_EXITSIG(child) != SIGCHLD)){ 744 if (child->p_pid == pid) { 745 child = NULL; 746 break; 747 } 748 continue; 749 } 750 751 error = 0; 752 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 753 break; 754 755 if (child->p_stat == SSTOP && 756 (child->p_flag & P_WAITED) == 0 && 757 (child->p_flag & P_TRACED || options & WUNTRACED)) { 758 if ((options & WNOWAIT) == 0) { 759 child->p_flag |= P_WAITED; 760 parent->p_nstopchild--; 761 } 762 break; 763 } 764 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 765 child = NULL; 766 break; 767 } 768 } 769 proclist_unlock_read(); 770 if (child != NULL || error != 0 || options & WNOHANG) { 771 *child_p = child; 772 return error; 773 } 774 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 775 if (error != 0) 776 return error; 777 } 778 } 779 780 /* 781 * Free a process after parent has taken all the state info. 782 */ 783 void 784 proc_free(struct proc *p) 785 { 786 struct proc *parent = p->p_pptr; 787 ksiginfo_t ksi; 788 int s; 789 790 KASSERT(p->p_nlwps == 0); 791 KASSERT(p->p_nzlwps == 0); 792 KASSERT(p->p_nrlwps == 0); 793 KASSERT(LIST_EMPTY(&p->p_lwps)); 794 795 /* 796 * If we got the child via ptrace(2) or procfs, and 797 * the parent is different (meaning the process was 798 * attached, rather than run as a child), then we need 799 * to give it back to the old parent, and send the 800 * parent the exit signal. The rest of the cleanup 801 * will be done when the old parent waits on the child. 802 */ 803 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 804 parent = p->p_opptr; 805 if (parent == NULL) 806 parent = initproc; 807 proc_reparent(p, parent); 808 p->p_opptr = NULL; 809 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 810 if (p->p_exitsig != 0) { 811 exit_psignal(p, parent, &ksi); 812 kpsignal(parent, &ksi, NULL); 813 } 814 wakeup(parent); 815 return; 816 } 817 818 scheduler_wait_hook(parent, p); 819 p->p_xstat = 0; 820 821 ruadd(&parent->p_stats->p_cru, p->p_ru); 822 823 /* 824 * At this point we are going to start freeing the final resources. 825 * If anyone tries to access the proc structure after here they 826 * will get a shock - bits are missing. 827 * Attempt to make it hard! 828 */ 829 830 p->p_stat = SIDL; /* not even a zombie any more */ 831 832 pool_put(&rusage_pool, p->p_ru); 833 834 /* 835 * Finally finished with old proc entry. 836 * Unlink it from its process group and free it. 837 */ 838 leavepgrp(p); 839 840 s = proclist_lock_write(); 841 LIST_REMOVE(p, p_list); /* off zombproc */ 842 p->p_pptr->p_nstopchild--; 843 LIST_REMOVE(p, p_sibling); 844 proclist_unlock_write(s); 845 846 /* 847 * Decrement the count of procs running with this uid. 848 */ 849 (void)chgproccnt(p->p_cred->p_ruid, -1); 850 851 /* 852 * Free up credentials. 853 */ 854 if (--p->p_cred->p_refcnt == 0) { 855 crfree(p->p_cred->pc_ucred); 856 pool_put(&pcred_pool, p->p_cred); 857 } 858 859 /* 860 * Release reference to text vnode 861 */ 862 if (p->p_textvp) 863 vrele(p->p_textvp); 864 865 /* Release any SA state. */ 866 if (p->p_sa) 867 sa_release(p); 868 869 /* Free proc structure and let pid be reallocated */ 870 proc_free_mem(p); 871 } 872 873 /* 874 * make process 'parent' the new parent of process 'child'. 875 * 876 * Must be called with proclist_lock_write() held. 877 */ 878 void 879 proc_reparent(struct proc *child, struct proc *parent) 880 { 881 882 if (child->p_pptr == parent) 883 return; 884 885 if (child->p_stat == SZOMB 886 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 887 child->p_pptr->p_nstopchild--; 888 parent->p_nstopchild++; 889 } 890 if (parent == initproc) 891 child->p_exitsig = SIGCHLD; 892 893 LIST_REMOVE(child, p_sibling); 894 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 895 child->p_pptr = parent; 896 }
Cache object: 6ff9ee963c0477ab889ca65161f856fa
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