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sys/kern/kern_exit.c
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1 /* $NetBSD: kern_exit.c,v 1.162.2.1 2007/04/01 16:16:20 bouyer Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1989, 1991, 1993 42 * The Regents of the University of California. All rights reserved. 43 * (c) UNIX System Laboratories, Inc. 44 * All or some portions of this file are derived from material licensed 45 * to the University of California by American Telephone and Telegraph 46 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 47 * the permission of UNIX System Laboratories, Inc. 48 * 49 * Redistribution and use in source and binary forms, with or without 50 * modification, are permitted provided that the following conditions 51 * are met: 52 * 1. Redistributions of source code must retain the above copyright 53 * notice, this list of conditions and the following disclaimer. 54 * 2. Redistributions in binary form must reproduce the above copyright 55 * notice, this list of conditions and the following disclaimer in the 56 * documentation and/or other materials provided with the distribution. 57 * 3. Neither the name of the University nor the names of its contributors 58 * may be used to endorse or promote products derived from this software 59 * without specific prior written permission. 60 * 61 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 62 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 63 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 64 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 65 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 66 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 67 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 68 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 69 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 70 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 71 * SUCH DAMAGE. 72 * 73 * @(#)kern_exit.c 8.10 (Berkeley) 2/23/95 74 */ 75 76 #include <sys/cdefs.h> 77 __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.162.2.1 2007/04/01 16:16:20 bouyer 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 ksiginfo_t ksi; 192 int do_psignal = 0; 193 194 p = l->l_proc; 195 196 if (__predict_false(p == initproc)) 197 panic("init died (signal %d, exit %d)", 198 WTERMSIG(rv), WEXITSTATUS(rv)); 199 200 p->p_flag |= P_WEXIT; 201 if (p->p_flag & P_STOPEXIT) { 202 sigminusset(&contsigmask, &p->p_sigctx.ps_siglist); 203 SCHED_LOCK(s); 204 p->p_stat = SSTOP; 205 l->l_stat = LSSTOP; 206 p->p_nrlwps--; 207 mi_switch(l, NULL); 208 SCHED_ASSERT_UNLOCKED(); 209 splx(s); 210 } 211 212 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid)); 213 /* 214 * Disable scheduler activation upcalls. 215 * We're trying to get out of here. 216 */ 217 sa = 0; 218 if (p->p_sa != NULL) { 219 l->l_flag &= ~L_SA; 220 #if 0 221 p->p_flag &= ~P_SA; 222 #endif 223 sa = 1; 224 } 225 226 #ifdef PGINPROF 227 vmsizmon(); 228 #endif 229 if (p->p_flag & P_PROFIL) 230 stopprofclock(p); 231 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 232 /* 233 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 234 * wake up the parent early to avoid deadlock. 235 */ 236 if (p->p_flag & P_PPWAIT) { 237 p->p_flag &= ~P_PPWAIT; 238 wakeup(p->p_pptr); 239 } 240 sigfillset(&p->p_sigctx.ps_sigignore); 241 sigemptyset(&p->p_sigctx.ps_siglist); 242 p->p_sigctx.ps_sigcheck = 0; 243 p->p_stat = SDYING; 244 timers_free(p, TIMERS_ALL); 245 246 if (sa || (p->p_nlwps > 1)) { 247 exit_lwps(l); 248 249 /* 250 * Collect thread u-areas. 251 */ 252 uvm_uarea_drain(FALSE); 253 } 254 255 #if defined(__HAVE_RAS) 256 ras_purgeall(p); 257 #endif 258 259 /* 260 * Close open files and release open-file table. 261 * This may block! 262 */ 263 fdfree(l); 264 cwdfree(p->p_cwdi); 265 p->p_cwdi = 0; 266 267 doexithooks(p); 268 269 if (SESS_LEADER(p)) { 270 struct session *sp = p->p_session; 271 struct tty *tp; 272 273 if (sp->s_ttyvp) { 274 /* 275 * Controlling process. 276 * Signal foreground pgrp, 277 * drain controlling terminal 278 * and revoke access to controlling terminal. 279 */ 280 tp = sp->s_ttyp; 281 s = spltty(); 282 TTY_LOCK(tp); 283 if (tp->t_session == sp) { 284 if (tp->t_pgrp) 285 pgsignal(tp->t_pgrp, SIGHUP, 1); 286 /* we can't guarantee the revoke will do this */ 287 tp->t_pgrp = NULL; 288 tp->t_session = NULL; 289 TTY_UNLOCK(tp); 290 splx(s); 291 SESSRELE(sp); 292 (void) ttywait(tp); 293 /* 294 * The tty could have been revoked 295 * if we blocked. 296 */ 297 if (sp->s_ttyvp) 298 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 299 } else { 300 TTY_UNLOCK(tp); 301 splx(s); 302 } 303 if (sp->s_ttyvp) 304 vrele(sp->s_ttyvp); 305 sp->s_ttyvp = NULL; 306 /* 307 * s_ttyp is not zero'd; we use this to indicate 308 * that the session once had a controlling terminal. 309 * (for logging and informational purposes) 310 */ 311 } 312 sp->s_leader = NULL; 313 } 314 fixjobc(p, p->p_pgrp, 0); 315 316 /* 317 * Collect accounting flags from the last remaining LWP (this one), 318 * and write out accounting data. 319 */ 320 p->p_acflag |= l->l_acflag; 321 (void)acct_process(l); 322 323 #ifdef KTRACE 324 /* 325 * Release trace file. 326 */ 327 ktrderef(p); 328 #endif 329 #ifdef SYSTRACE 330 systrace_sys_exit(p); 331 #endif 332 333 /* 334 * If emulation has process exit hook, call it now. 335 * Set the exit status now so that the exit hook has 336 * an opportunity to tweak it (COMPAT_LINUX requires 337 * this for thread group emulation) 338 */ 339 p->p_xstat = rv; 340 if (p->p_emul->e_proc_exit) 341 (*p->p_emul->e_proc_exit)(p); 342 343 /* 344 * Free the VM resources we're still holding on to. 345 * We must do this from a valid thread because doing 346 * so may block. This frees vmspace, which we don't 347 * need anymore. The only remaining lwp is the one 348 * we run at this moment, nothing runs in userland 349 * anymore. 350 */ 351 uvm_proc_exit(p); 352 353 /* Release substructures. These might need to sleep. */ 354 kauth_cred_free(l->l_cred); 355 sigactsfree(p->p_sigacts); 356 p->p_sigacts = NULL; 357 358 /* 359 * Finalize the last LWP's specificdata, as well as the 360 * specificdata for the proc itself. 361 */ 362 lwp_finispecific(l); 363 proc_finispecific(p); 364 365 /* 366 * Give machine-dependent code a chance to free any 367 * MD LWP resources while we can still block. This must be done 368 * before uvm_lwp_exit(), in case these resources are in the 369 * PCB. 370 * THIS IS LAST BLOCKING OPERATION. 371 */ 372 #ifndef __NO_CPU_LWP_FREE 373 cpu_lwp_free(l, 1); 374 #endif 375 376 pmap_deactivate(l); 377 378 /* 379 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 380 */ 381 382 /* 383 * Save final rusage info, adding in child rusage info and self times. 384 * In order to pick up the time for the current execution, we must 385 * do this before unlinking the lwp from l_list. 386 */ 387 *p->p_ru = p->p_stats->p_ru; 388 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 389 ruadd(p->p_ru, &p->p_stats->p_cru); 390 391 /* 392 * Notify interested parties of our demise. 393 */ 394 KNOTE(&p->p_klist, NOTE_EXIT); 395 396 #if PERFCTRS 397 /* 398 * Save final PMC information in parent process & clean up. 399 */ 400 if (PMC_ENABLED(p)) { 401 pmc_save_context(p); 402 pmc_accumulate(p->p_pptr, p); 403 pmc_process_exit(p); 404 } 405 #endif 406 407 s = proclist_lock_write(); 408 /* 409 * Reset p_opptr pointer of all former children which got 410 * traced by another process and were reparented. We reset 411 * it to NULL here; the trace detach code then reparents 412 * the child to initproc. We only check allproc list, since 413 * eventual former children on zombproc list won't reference 414 * p_opptr anymore. 415 */ 416 if (p->p_flag & P_CHTRACED) { 417 PROCLIST_FOREACH(q, &allproc) { 418 if (q->p_opptr == p) 419 q->p_opptr = NULL; 420 } 421 } 422 423 /* 424 * Give orphaned children to init(8). 425 */ 426 q = LIST_FIRST(&p->p_children); 427 if (q) /* only need this if any child is SZOMB */ 428 wakeup(initproc); 429 for (; q != NULL; q = nq) { 430 nq = LIST_NEXT(q, p_sibling); 431 432 /* 433 * Traced processes are killed since their existence 434 * means someone is screwing up. Since we reset the 435 * trace flags, the logic in sys_wait4() would not be 436 * triggered to reparent the process to its 437 * original parent, so we must do this here. 438 */ 439 if (q->p_flag & P_TRACED) { 440 if (q->p_opptr != q->p_pptr) { 441 struct proc *t = q->p_opptr; 442 proc_reparent(q, t ? t : initproc); 443 q->p_opptr = NULL; 444 } else 445 proc_reparent(q, initproc); 446 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL); 447 killproc(q, "orphaned traced process"); 448 } else { 449 proc_reparent(q, initproc); 450 } 451 } 452 453 /* 454 * Move proc from allproc to zombproc, it's now ready 455 * to be collected by parent. Remaining lwp resources 456 * will be freed in lwp_exit2() once we've switch to idle 457 * context. 458 * Changing the state to SZOMB stops it being found by pfind(). 459 */ 460 LIST_REMOVE(p, p_list); 461 LIST_INSERT_HEAD(&zombproc, p, p_list); 462 p->p_stat = SZOMB; 463 464 LIST_REMOVE(l, l_list); 465 LIST_REMOVE(l, l_sibling); 466 l->l_flag |= L_DETACHED; /* detached from proc too */ 467 l->l_stat = LSDEAD; 468 469 KASSERT(p->p_nrlwps == 1); 470 KASSERT(p->p_nlwps == 1); 471 p->p_nrlwps--; 472 p->p_nlwps--; 473 474 /* Put in front of parent's sibling list for parent to collect it */ 475 q = p->p_pptr; 476 q->p_nstopchild++; 477 if (LIST_FIRST(&q->p_children) != p) { 478 /* Put child where it can be found quickly */ 479 LIST_REMOVE(p, p_sibling); 480 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 481 } 482 483 /* 484 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 485 * flag set, notify init instead (and hope it will handle 486 * this situation). 487 */ 488 if (q->p_flag & (P_NOCLDWAIT|P_CLDSIGIGN)) { 489 proc_reparent(p, initproc); 490 491 /* 492 * If this was the last child of our parent, notify 493 * parent, so in case he was wait(2)ing, he will 494 * continue. 495 */ 496 if (LIST_FIRST(&q->p_children) == NULL) 497 wakeup(q); 498 } 499 500 /* 501 * Clear curlwp after we've done all operations 502 * that could block, and before tearing down the rest 503 * of the process state that might be used from clock, etc. 504 * Also, can't clear curlwp while we're still runnable, 505 * as we're not on a run queue (we are current, just not 506 * a proper proc any longer!). 507 * 508 * Other substructures are freed from wait(). 509 */ 510 curlwp = 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 #ifdef DEBUG 534 /* Nothing should use the process link anymore */ 535 l->l_proc = NULL; 536 #endif 537 538 /* This process no longer needs to hold the kernel lock. */ 539 KERNEL_PROC_UNLOCK(l); 540 541 /* 542 * Finally, call machine-dependent code to switch to a new 543 * context (possibly the idle context). Once we are no longer 544 * using the dead lwp's stack, lwp_exit2() will be called 545 * to arrange for the resources to be released. 546 * 547 * Note that cpu_exit() will end with a call equivalent to 548 * cpu_switch(), finishing our execution (pun intended). 549 */ 550 551 uvmexp.swtch++; 552 cpu_exit(l); 553 } 554 555 void 556 exit_lwps(struct lwp *l) 557 { 558 struct proc *p; 559 struct lwp *l2; 560 struct sadata_vp *vp; 561 int s, error; 562 lwpid_t waited; 563 564 p = l->l_proc; 565 566 /* XXX SMP 567 * This would be the right place to IPI any LWPs running on 568 * other processors so that they can notice the userret exit hook. 569 */ 570 p->p_userret = lwp_exit_hook; 571 p->p_userret_arg = NULL; 572 573 if (p->p_sa) { 574 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 575 /* 576 * Make SA-cached LWPs normal process runnable 577 * LWPs so that they'll also self-destruct. 578 */ 579 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 580 p->p_pid, vp->savp_id)); 581 SCHED_LOCK(s); 582 while ((l2 = sa_getcachelwp(vp)) != 0) { 583 l2->l_priority = l2->l_usrpri; 584 setrunnable(l2); 585 DPRINTF(("%d ", l2->l_lid)); 586 } 587 SCHED_UNLOCK(s); 588 DPRINTF(("\n")); 589 590 /* 591 * Clear wokenq, the LWPs on the queue will 592 * run below. 593 */ 594 vp->savp_wokenq_head = NULL; 595 } 596 } 597 598 retry: 599 /* 600 * Interrupt LWPs in interruptable sleep, unsuspend suspended 601 * LWPs, make detached LWPs undetached (so we can wait for 602 * them) and then wait for everyone else to finish. 603 */ 604 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 605 l2->l_flag &= ~(L_DETACHED|L_SA); 606 607 SCHED_LOCK(s); 608 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 609 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 610 setrunnable(l2); 611 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 612 p->p_pid, l2->l_lid)); 613 } 614 SCHED_UNLOCK(s); 615 } 616 617 618 while (p->p_nlwps > 1) { 619 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 620 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 621 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 622 if (error == EDEADLK) { 623 /* 624 * LWPs can get suspended/slept behind us. 625 * (eg. sa_setwoken) 626 * kick them again and retry. 627 */ 628 goto retry; 629 } 630 if (error) 631 panic("exit_lwps: lwp_wait1 failed with error %d", 632 error); 633 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 634 } 635 636 p->p_userret = NULL; 637 } 638 639 /* Wrapper function for use in p_userret */ 640 static void 641 lwp_exit_hook(struct lwp *l, void *arg) 642 { 643 644 KERNEL_PROC_LOCK(l); 645 lwp_exit(l); 646 } 647 648 int 649 sys_wait4(struct lwp *l, void *v, register_t *retval) 650 { 651 struct sys_wait4_args /* { 652 syscallarg(int) pid; 653 syscallarg(int *) status; 654 syscallarg(int) options; 655 syscallarg(struct rusage *) rusage; 656 } */ *uap = v; 657 struct proc *child, *parent; 658 int status, error; 659 660 parent = l->l_proc; 661 662 if (SCARG(uap, pid) == 0) 663 SCARG(uap, pid) = -parent->p_pgid; 664 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 665 return (EINVAL); 666 667 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 668 &child); 669 if (error != 0) 670 return error; 671 if (child == NULL) { 672 *retval = 0; 673 return 0; 674 } 675 676 /* 677 * Collect child u-areas. 678 */ 679 uvm_uarea_drain(FALSE); 680 681 retval[0] = child->p_pid; 682 683 if (P_ZOMBIE(child)) { 684 if (SCARG(uap, status)) { 685 status = child->p_xstat; /* convert to int */ 686 error = copyout(&status, SCARG(uap, status), 687 sizeof(status)); 688 if (error) 689 return (error); 690 } 691 if (SCARG(uap, rusage)) { 692 error = copyout(child->p_ru, SCARG(uap, rusage), 693 sizeof(struct rusage)); 694 if (error) 695 return (error); 696 } 697 698 proc_free(child); 699 return 0; 700 } 701 702 /* child state must be SSTOP */ 703 if (SCARG(uap, status)) { 704 status = W_STOPCODE(child->p_xstat); 705 return copyout(&status, SCARG(uap, status), sizeof(status)); 706 } 707 return 0; 708 } 709 710 /* 711 * Scan list of child processes for a child process that has stopped or 712 * exited. Used by sys_wait4 and 'compat' equivalents. 713 */ 714 int 715 find_stopped_child(struct proc *parent, pid_t pid, int options, 716 struct proc **child_p) 717 { 718 struct proc *child; 719 int error; 720 721 for (;;) { 722 proclist_lock_read(); 723 error = ECHILD; 724 LIST_FOREACH(child, &parent->p_children, p_sibling) { 725 if (pid >= 0) { 726 if (child->p_pid != pid) { 727 child = p_find(pid, PFIND_ZOMBIE | 728 PFIND_LOCKED); 729 if (child == NULL 730 || child->p_pptr != parent) { 731 child = NULL; 732 break; 733 } 734 } 735 } else 736 if (pid != WAIT_ANY && child->p_pgid != -pid) 737 /* child not in correct pgrp */ 738 continue; 739 /* 740 * Wait for processes with p_exitsig != SIGCHLD 741 * processes only if WALTSIG is set; wait for 742 * processes with p_exitsig == SIGCHLD only 743 * if WALTSIG is clear. 744 */ 745 if (((options & WALLSIG) == 0) && 746 (options & WALTSIG ? child->p_exitsig == SIGCHLD 747 : P_EXITSIG(child) != SIGCHLD)){ 748 if (child->p_pid == pid) { 749 child = NULL; 750 break; 751 } 752 continue; 753 } 754 755 error = 0; 756 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 757 break; 758 759 if (child->p_stat == SSTOP && 760 (child->p_flag & P_WAITED) == 0 && 761 (child->p_flag & P_TRACED || options & WUNTRACED)) { 762 if ((options & WNOWAIT) == 0) { 763 child->p_flag |= P_WAITED; 764 parent->p_nstopchild--; 765 } 766 break; 767 } 768 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 769 child = NULL; 770 break; 771 } 772 } 773 proclist_unlock_read(); 774 if (child != NULL || error != 0 || options & WNOHANG) { 775 *child_p = child; 776 return error; 777 } 778 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 779 if (error != 0) 780 return error; 781 } 782 } 783 784 /* 785 * Free a process after parent has taken all the state info. 786 */ 787 void 788 proc_free(struct proc *p) 789 { 790 struct proc *parent = p->p_pptr; 791 ksiginfo_t ksi; 792 int s; 793 794 KASSERT(p->p_nlwps == 0); 795 KASSERT(p->p_nzlwps == 0); 796 KASSERT(p->p_nrlwps == 0); 797 KASSERT(LIST_EMPTY(&p->p_lwps)); 798 799 /* 800 * If we got the child via ptrace(2) or procfs, and 801 * the parent is different (meaning the process was 802 * attached, rather than run as a child), then we need 803 * to give it back to the old parent, and send the 804 * parent the exit signal. The rest of the cleanup 805 * will be done when the old parent waits on the child. 806 */ 807 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 808 parent = p->p_opptr; 809 if (parent == NULL) 810 parent = initproc; 811 proc_reparent(p, parent); 812 p->p_opptr = NULL; 813 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE|P_SYSCALL); 814 if (p->p_exitsig != 0) { 815 exit_psignal(p, parent, &ksi); 816 kpsignal(parent, &ksi, NULL); 817 } 818 wakeup(parent); 819 return; 820 } 821 822 scheduler_wait_hook(parent, p); 823 p->p_xstat = 0; 824 825 ruadd(&parent->p_stats->p_cru, p->p_ru); 826 827 /* 828 * At this point we are going to start freeing the final resources. 829 * If anyone tries to access the proc structure after here they 830 * will get a shock - bits are missing. 831 * Attempt to make it hard! 832 */ 833 834 p->p_stat = SIDL; /* not even a zombie any more */ 835 836 pool_put(&rusage_pool, p->p_ru); 837 838 /* 839 * Finally finished with old proc entry. 840 * Unlink it from its process group and free it. 841 */ 842 leavepgrp(p); 843 844 s = proclist_lock_write(); 845 LIST_REMOVE(p, p_list); /* off zombproc */ 846 p->p_pptr->p_nstopchild--; 847 LIST_REMOVE(p, p_sibling); 848 proclist_unlock_write(s); 849 850 /* 851 * Decrement the count of procs running with this uid. 852 */ 853 (void)chgproccnt(kauth_cred_getuid(p->p_cred), -1); 854 855 /* 856 * Free up credentials. 857 */ 858 kauth_cred_free(p->p_cred); 859 860 /* 861 * Release reference to text vnode 862 */ 863 if (p->p_textvp) 864 vrele(p->p_textvp); 865 866 /* Release any SA state. */ 867 if (p->p_sa) 868 sa_release(p); 869 870 /* Release remaining substructures. */ 871 limfree(p->p_limit); 872 pstatsfree(p->p_stats); 873 874 /* Free proc structure and let pid be reallocated */ 875 proc_free_mem(p); 876 } 877 878 /* 879 * make process 'parent' the new parent of process 'child'. 880 * 881 * Must be called with proclist_lock_write() held. 882 */ 883 void 884 proc_reparent(struct proc *child, struct proc *parent) 885 { 886 887 if (child->p_pptr == parent) 888 return; 889 890 if (child->p_stat == SZOMB 891 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 892 child->p_pptr->p_nstopchild--; 893 parent->p_nstopchild++; 894 } 895 if (parent == initproc) 896 child->p_exitsig = SIGCHLD; 897 898 LIST_REMOVE(child, p_sibling); 899 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 900 child->p_pptr = parent; 901 }
Cache object: 1926420b60f94bf8f3749120b407d95a
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