1 /* $NetBSD: kern_exit.c,v 1.146 2005/03/30 17:07:50 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 1.146 2005/03/30 17:07:50 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 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 p->p_nrlwps--; 453 p->p_nlwps--; 454 455 /* Put in front of parent's sibling list for parent to collect it */ 456 q = p->p_pptr; 457 q->p_nstopchild++; 458 if (LIST_FIRST(&q->p_children) != p) { 459 /* Put child where it can be found quickly */ 460 LIST_REMOVE(p, p_sibling); 461 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 462 } 463 464 /* 465 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 466 * flag set, notify init instead (and hope it will handle 467 * this situation). 468 */ 469 if (q->p_flag & (P_NOCLDWAIT|P_CLDSIGIGN)) { 470 proc_reparent(p, initproc); 471 472 /* 473 * If this was the last child of our parent, notify 474 * parent, so in case he was wait(2)ing, he will 475 * continue. 476 */ 477 if (LIST_FIRST(&q->p_children) == NULL) 478 wakeup(q); 479 } 480 481 /* 482 * Clear curlwp after we've done all operations 483 * that could block, and before tearing down the rest 484 * of the process state that might be used from clock, etc. 485 * Also, can't clear curlwp while we're still runnable, 486 * as we're not on a run queue (we are current, just not 487 * a proper proc any longer!). 488 * 489 * Other substructures are freed from wait(). 490 */ 491 curlwp = NULL; 492 493 /* Delay release until after dropping the proclist lock */ 494 plim = p->p_limit; 495 pstats = p->p_stats; 496 ps = p->p_sigacts; 497 498 p->p_limit = NULL; 499 p->p_stats = NULL; 500 p->p_sigacts = NULL; 501 502 /* Reload parent pointer, since p may have been reparented above */ 503 q = p->p_pptr; 504 505 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) { 506 exit_psignal(p, q, &ksi); 507 do_psignal = 1; 508 } 509 510 /* 511 * Once we release the proclist lock, we shouldn't touch the 512 * process structure anymore, since it's now on the zombie 513 * list and available for collection by the parent. 514 */ 515 proclist_unlock_write(s); 516 517 if (do_psignal) 518 kpsignal(q, &ksi, NULL); 519 520 /* Wake up the parent so it can get exit status. */ 521 wakeup(q); 522 523 /* Release substructures */ 524 sigactsfree(ps); 525 limfree(plim); 526 pstatsfree(pstats); 527 528 #ifdef DEBUG 529 /* Nothing should use the process link anymore */ 530 l->l_proc = NULL; 531 #endif 532 533 /* This process no longer needs to hold the kernel lock. */ 534 KERNEL_PROC_UNLOCK(l); 535 536 /* 537 * Finally, call machine-dependent code to switch to a new 538 * context (possibly the idle context). Once we are no longer 539 * using the dead lwp's stack, lwp_exit2() will be called 540 * to arrange for the resources to be released. 541 * 542 * Note that cpu_exit() will end with a call equivalent to 543 * cpu_switch(), finishing our execution (pun intended). 544 */ 545 546 uvmexp.swtch++; 547 cpu_exit(l); 548 } 549 550 void 551 exit_lwps(struct lwp *l) 552 { 553 struct proc *p; 554 struct lwp *l2; 555 struct sadata_vp *vp; 556 int s, error; 557 lwpid_t waited; 558 559 p = l->l_proc; 560 561 /* XXX SMP 562 * This would be the right place to IPI any LWPs running on 563 * other processors so that they can notice the userret exit hook. 564 */ 565 p->p_userret = lwp_exit_hook; 566 p->p_userret_arg = NULL; 567 568 if (p->p_sa) { 569 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 570 /* 571 * Make SA-cached LWPs normal process runnable 572 * LWPs so that they'll also self-destruct. 573 */ 574 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 575 p->p_pid, vp->savp_id)); 576 SCHED_LOCK(s); 577 while ((l2 = sa_getcachelwp(vp)) != 0) { 578 l2->l_priority = l2->l_usrpri; 579 setrunnable(l2); 580 DPRINTF(("%d ", l2->l_lid)); 581 } 582 SCHED_UNLOCK(s); 583 DPRINTF(("\n")); 584 585 /* 586 * Clear wokenq, the LWPs on the queue will 587 * run below. 588 */ 589 vp->savp_wokenq_head = NULL; 590 } 591 } 592 593 /* 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 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 602 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 603 SCHED_LOCK(s); 604 setrunnable(l2); 605 SCHED_UNLOCK(s); 606 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 607 p->p_pid, l2->l_lid)); 608 } 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) 617 panic("exit_lwps: lwp_wait1 failed with error %d\n", 618 error); 619 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 620 } 621 622 p->p_userret = NULL; 623 } 624 625 /* Wrapper function for use in p_userret */ 626 static void 627 lwp_exit_hook(struct lwp *l, void *arg) 628 { 629 KERNEL_PROC_LOCK(l); 630 lwp_exit(l); 631 } 632 633 int 634 sys_wait4(struct lwp *l, void *v, register_t *retval) 635 { 636 struct sys_wait4_args /* { 637 syscallarg(int) pid; 638 syscallarg(int *) status; 639 syscallarg(int) options; 640 syscallarg(struct rusage *) rusage; 641 } */ *uap = v; 642 struct proc *child, *parent; 643 int status, error; 644 645 parent = l->l_proc; 646 647 if (SCARG(uap, pid) == 0) 648 SCARG(uap, pid) = -parent->p_pgid; 649 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 650 return (EINVAL); 651 652 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 653 &child); 654 if (error != 0) 655 return error; 656 if (child == NULL) { 657 *retval = 0; 658 return 0; 659 } 660 661 /* 662 * Collect child u-areas. 663 */ 664 uvm_uarea_drain(FALSE); 665 666 retval[0] = child->p_pid; 667 668 if (P_ZOMBIE(child)) { 669 if (SCARG(uap, status)) { 670 status = child->p_xstat; /* convert to int */ 671 error = copyout(&status, SCARG(uap, status), 672 sizeof(status)); 673 if (error) 674 return (error); 675 } 676 if (SCARG(uap, rusage)) { 677 error = copyout(child->p_ru, SCARG(uap, rusage), 678 sizeof(struct rusage)); 679 if (error) 680 return (error); 681 } 682 683 proc_free(child); 684 return 0; 685 } 686 687 /* child state must be SSTOP */ 688 if (SCARG(uap, status)) { 689 status = W_STOPCODE(child->p_xstat); 690 return copyout(&status, SCARG(uap, status), sizeof(status)); 691 } 692 return 0; 693 } 694 695 /* 696 * Scan list of child processes for a child process that has stopped or 697 * exited. Used by sys_wait4 and 'compat' equivalents. 698 */ 699 int 700 find_stopped_child(struct proc *parent, pid_t pid, int options, 701 struct proc **child_p) 702 { 703 struct proc *child; 704 int error; 705 706 for (;;) { 707 proclist_lock_read(); 708 error = ECHILD; 709 LIST_FOREACH(child, &parent->p_children, p_sibling) { 710 if (pid >= 0) { 711 if (child->p_pid != pid) { 712 child = p_find(pid, PFIND_ZOMBIE | 713 PFIND_LOCKED); 714 if (child == NULL 715 || child->p_pptr != parent) { 716 child = NULL; 717 break; 718 } 719 } 720 } else 721 if (pid != WAIT_ANY && child->p_pgid != -pid) 722 /* child not in correct pgrp */ 723 continue; 724 /* 725 * Wait for processes with p_exitsig != SIGCHLD 726 * processes only if WALTSIG is set; wait for 727 * processes with p_exitsig == SIGCHLD only 728 * if WALTSIG is clear. 729 */ 730 if (((options & WALLSIG) == 0) && 731 (options & WALTSIG ? child->p_exitsig == SIGCHLD 732 : P_EXITSIG(child) != SIGCHLD)){ 733 if (child->p_pid == pid) { 734 child = NULL; 735 break; 736 } 737 continue; 738 } 739 740 error = 0; 741 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 742 break; 743 744 if (child->p_stat == SSTOP && 745 (child->p_flag & P_WAITED) == 0 && 746 (child->p_flag & P_TRACED || options & WUNTRACED)) { 747 if ((options & WNOWAIT) == 0) { 748 child->p_flag |= P_WAITED; 749 parent->p_nstopchild--; 750 } 751 break; 752 } 753 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 754 child = NULL; 755 break; 756 } 757 } 758 proclist_unlock_read(); 759 if (child != NULL || error != 0 || options & WNOHANG) { 760 *child_p = child; 761 return error; 762 } 763 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 764 if (error != 0) 765 return error; 766 } 767 } 768 769 /* 770 * Free a process after parent has taken all the state info. 771 */ 772 void 773 proc_free(struct proc *p) 774 { 775 struct proc *parent = p->p_pptr; 776 ksiginfo_t ksi; 777 int s; 778 779 KASSERT(p->p_nlwps == 0); 780 KASSERT(p->p_nzlwps == 0); 781 KASSERT(p->p_nrlwps == 0); 782 KASSERT(LIST_EMPTY(&p->p_lwps)); 783 784 /* 785 * If we got the child via ptrace(2) or procfs, and 786 * the parent is different (meaning the process was 787 * attached, rather than run as a child), then we need 788 * to give it back to the old parent, and send the 789 * parent the exit signal. The rest of the cleanup 790 * will be done when the old parent waits on the child. 791 */ 792 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 793 parent = p->p_opptr; 794 if (parent == NULL) 795 parent = initproc; 796 proc_reparent(p, parent); 797 p->p_opptr = NULL; 798 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 799 if (p->p_exitsig != 0) { 800 exit_psignal(p, parent, &ksi); 801 kpsignal(parent, &ksi, NULL); 802 } 803 wakeup(parent); 804 return; 805 } 806 807 scheduler_wait_hook(parent, p); 808 p->p_xstat = 0; 809 810 ruadd(&parent->p_stats->p_cru, p->p_ru); 811 812 /* 813 * At this point we are going to start freeing the final resources. 814 * If anyone tries to access the proc structure after here they 815 * will get a shock - bits are missing. 816 * Attempt to make it hard! 817 */ 818 819 p->p_stat = SIDL; /* not even a zombie any more */ 820 821 pool_put(&rusage_pool, p->p_ru); 822 823 /* 824 * Finally finished with old proc entry. 825 * Unlink it from its process group and free it. 826 */ 827 leavepgrp(p); 828 829 s = proclist_lock_write(); 830 LIST_REMOVE(p, p_list); /* off zombproc */ 831 p->p_pptr->p_nstopchild--; 832 LIST_REMOVE(p, p_sibling); 833 proclist_unlock_write(s); 834 835 /* 836 * Decrement the count of procs running with this uid. 837 */ 838 (void)chgproccnt(p->p_cred->p_ruid, -1); 839 840 /* 841 * Free up credentials. 842 */ 843 if (--p->p_cred->p_refcnt == 0) { 844 crfree(p->p_cred->pc_ucred); 845 pool_put(&pcred_pool, p->p_cred); 846 } 847 848 /* 849 * Release reference to text vnode 850 */ 851 if (p->p_textvp) 852 vrele(p->p_textvp); 853 854 /* Release any SA state. */ 855 if (p->p_sa) 856 sa_release(p); 857 858 /* Free proc structure and let pid be reallocated */ 859 proc_free_mem(p); 860 } 861 862 /* 863 * make process 'parent' the new parent of process 'child'. 864 * 865 * Must be called with proclist_lock_write() held. 866 */ 867 void 868 proc_reparent(struct proc *child, struct proc *parent) 869 { 870 871 if (child->p_pptr == parent) 872 return; 873 874 if (child->p_stat == SZOMB 875 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 876 child->p_pptr->p_nstopchild--; 877 parent->p_nstopchild++; 878 } 879 if (parent == initproc) 880 child->p_exitsig = SIGCHLD; 881 882 LIST_REMOVE(child, p_sibling); 883 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 884 child->p_pptr = parent; 885 } 886