1 /* $NetBSD: kern_exit.c,v 1.148 2005/05/29 22:24:15 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 1.148 2005/05/29 22:24:15 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(p); 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(p); 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 psignal(q, SIGKILL); 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|L_PROCEXIT; /* detached from proc too */ 447 l->l_stat = LSDEAD; 448 449 p->p_nrlwps--; 450 p->p_nlwps--; 451 452 /* Put in front of parent's sibling list for parent to collect it */ 453 q = p->p_pptr; 454 q->p_nstopchild++; 455 if (LIST_FIRST(&q->p_children) != p) { 456 /* Put child where it can be found quickly */ 457 LIST_REMOVE(p, p_sibling); 458 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 459 } 460 461 /* 462 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 463 * flag set, notify init instead (and hope it will handle 464 * this situation). 465 */ 466 if (q->p_flag & (P_NOCLDWAIT|P_CLDSIGIGN)) { 467 proc_reparent(p, initproc); 468 469 /* 470 * If this was the last child of our parent, notify 471 * parent, so in case he was wait(2)ing, he will 472 * continue. 473 */ 474 if (LIST_FIRST(&q->p_children) == NULL) 475 wakeup(q); 476 } 477 478 /* 479 * Clear curlwp after we've done all operations 480 * that could block, and before tearing down the rest 481 * of the process state that might be used from clock, etc. 482 * Also, can't clear curlwp while we're still runnable, 483 * as we're not on a run queue (we are current, just not 484 * a proper proc any longer!). 485 * 486 * Other substructures are freed from wait(). 487 */ 488 curlwp = NULL; 489 490 /* Delay release until after dropping the proclist lock */ 491 plim = p->p_limit; 492 pstats = p->p_stats; 493 ps = p->p_sigacts; 494 495 p->p_limit = NULL; 496 p->p_stats = NULL; 497 p->p_sigacts = NULL; 498 499 /* Reload parent pointer, since p may have been reparented above */ 500 q = p->p_pptr; 501 502 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) { 503 exit_psignal(p, q, &ksi); 504 do_psignal = 1; 505 } 506 507 /* 508 * Once we release the proclist lock, we shouldn't touch the 509 * process structure anymore, since it's now on the zombie 510 * list and available for collection by the parent. 511 */ 512 proclist_unlock_write(s); 513 514 if (do_psignal) 515 kpsignal(q, &ksi, NULL); 516 517 /* Wake up the parent so it can get exit status. */ 518 wakeup(q); 519 520 /* Release substructures */ 521 sigactsfree(ps); 522 limfree(plim); 523 pstatsfree(pstats); 524 525 #ifdef DEBUG 526 /* Nothing should use the process link anymore */ 527 l->l_proc = NULL; 528 #endif 529 530 /* This process no longer needs to hold the kernel lock. */ 531 KERNEL_PROC_UNLOCK(l); 532 533 /* 534 * Finally, call machine-dependent code to switch to a new 535 * context (possibly the idle context). Once we are no longer 536 * using the dead lwp's stack, lwp_exit2() will be called 537 * to arrange for the resources to be released. 538 * 539 * Note that cpu_exit() will end with a call equivalent to 540 * cpu_switch(), finishing our execution (pun intended). 541 */ 542 543 uvmexp.swtch++; 544 cpu_exit(l); 545 } 546 547 void 548 exit_lwps(struct lwp *l) 549 { 550 struct proc *p; 551 struct lwp *l2; 552 struct sadata_vp *vp; 553 int s, error; 554 lwpid_t waited; 555 556 p = l->l_proc; 557 558 /* XXX SMP 559 * This would be the right place to IPI any LWPs running on 560 * other processors so that they can notice the userret exit hook. 561 */ 562 p->p_userret = lwp_exit_hook; 563 p->p_userret_arg = NULL; 564 565 if (p->p_sa) { 566 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 567 /* 568 * Make SA-cached LWPs normal process runnable 569 * LWPs so that they'll also self-destruct. 570 */ 571 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 572 p->p_pid, vp->savp_id)); 573 SCHED_LOCK(s); 574 while ((l2 = sa_getcachelwp(vp)) != 0) { 575 l2->l_priority = l2->l_usrpri; 576 setrunnable(l2); 577 DPRINTF(("%d ", l2->l_lid)); 578 } 579 SCHED_UNLOCK(s); 580 DPRINTF(("\n")); 581 582 /* 583 * Clear wokenq, the LWPs on the queue will 584 * run below. 585 */ 586 vp->savp_wokenq_head = NULL; 587 } 588 } 589 590 /* 591 * Interrupt LWPs in interruptable sleep, unsuspend suspended 592 * LWPs, make detached LWPs undetached (so we can wait for 593 * them) and then wait for everyone else to finish. 594 */ 595 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 596 l2->l_flag &= ~(L_DETACHED|L_SA); 597 598 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 599 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 600 SCHED_LOCK(s); 601 setrunnable(l2); 602 SCHED_UNLOCK(s); 603 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 604 p->p_pid, l2->l_lid)); 605 } 606 } 607 608 609 while (p->p_nlwps > 1) { 610 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 611 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 612 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 613 if (error) 614 panic("exit_lwps: lwp_wait1 failed with error %d", 615 error); 616 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 617 } 618 619 p->p_userret = NULL; 620 } 621 622 /* Wrapper function for use in p_userret */ 623 static void 624 lwp_exit_hook(struct lwp *l, void *arg) 625 { 626 KERNEL_PROC_LOCK(l); 627 lwp_exit(l); 628 } 629 630 int 631 sys_wait4(struct lwp *l, void *v, register_t *retval) 632 { 633 struct sys_wait4_args /* { 634 syscallarg(int) pid; 635 syscallarg(int *) status; 636 syscallarg(int) options; 637 syscallarg(struct rusage *) rusage; 638 } */ *uap = v; 639 struct proc *child, *parent; 640 int status, error; 641 642 parent = l->l_proc; 643 644 if (SCARG(uap, pid) == 0) 645 SCARG(uap, pid) = -parent->p_pgid; 646 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 647 return (EINVAL); 648 649 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 650 &child); 651 if (error != 0) 652 return error; 653 if (child == NULL) { 654 *retval = 0; 655 return 0; 656 } 657 658 /* 659 * Collect child u-areas. 660 */ 661 uvm_uarea_drain(FALSE); 662 663 retval[0] = child->p_pid; 664 665 if (P_ZOMBIE(child)) { 666 if (SCARG(uap, status)) { 667 status = child->p_xstat; /* convert to int */ 668 error = copyout(&status, SCARG(uap, status), 669 sizeof(status)); 670 if (error) 671 return (error); 672 } 673 if (SCARG(uap, rusage)) { 674 error = copyout(child->p_ru, SCARG(uap, rusage), 675 sizeof(struct rusage)); 676 if (error) 677 return (error); 678 } 679 680 proc_free(child); 681 return 0; 682 } 683 684 /* child state must be SSTOP */ 685 if (SCARG(uap, status)) { 686 status = W_STOPCODE(child->p_xstat); 687 return copyout(&status, SCARG(uap, status), sizeof(status)); 688 } 689 return 0; 690 } 691 692 /* 693 * Scan list of child processes for a child process that has stopped or 694 * exited. Used by sys_wait4 and 'compat' equivalents. 695 */ 696 int 697 find_stopped_child(struct proc *parent, pid_t pid, int options, 698 struct proc **child_p) 699 { 700 struct proc *child; 701 int error; 702 703 for (;;) { 704 proclist_lock_read(); 705 error = ECHILD; 706 LIST_FOREACH(child, &parent->p_children, p_sibling) { 707 if (pid >= 0) { 708 if (child->p_pid != pid) { 709 child = p_find(pid, PFIND_ZOMBIE | 710 PFIND_LOCKED); 711 if (child == NULL 712 || child->p_pptr != parent) { 713 child = NULL; 714 break; 715 } 716 } 717 } else 718 if (pid != WAIT_ANY && child->p_pgid != -pid) 719 /* child not in correct pgrp */ 720 continue; 721 /* 722 * Wait for processes with p_exitsig != SIGCHLD 723 * processes only if WALTSIG is set; wait for 724 * processes with p_exitsig == SIGCHLD only 725 * if WALTSIG is clear. 726 */ 727 if (((options & WALLSIG) == 0) && 728 (options & WALTSIG ? child->p_exitsig == SIGCHLD 729 : P_EXITSIG(child) != SIGCHLD)){ 730 if (child->p_pid == pid) { 731 child = NULL; 732 break; 733 } 734 continue; 735 } 736 737 error = 0; 738 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 739 break; 740 741 if (child->p_stat == SSTOP && 742 (child->p_flag & P_WAITED) == 0 && 743 (child->p_flag & P_TRACED || options & WUNTRACED)) { 744 if ((options & WNOWAIT) == 0) { 745 child->p_flag |= P_WAITED; 746 parent->p_nstopchild--; 747 } 748 break; 749 } 750 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 751 child = NULL; 752 break; 753 } 754 } 755 proclist_unlock_read(); 756 if (child != NULL || error != 0 || options & WNOHANG) { 757 *child_p = child; 758 return error; 759 } 760 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 761 if (error != 0) 762 return error; 763 } 764 } 765 766 /* 767 * Free a process after parent has taken all the state info. 768 */ 769 void 770 proc_free(struct proc *p) 771 { 772 struct proc *parent = p->p_pptr; 773 ksiginfo_t ksi; 774 int s; 775 776 KASSERT(p->p_nlwps == 0); 777 KASSERT(p->p_nzlwps == 0); 778 KASSERT(p->p_nrlwps == 0); 779 KASSERT(LIST_EMPTY(&p->p_lwps)); 780 781 /* 782 * If we got the child via ptrace(2) or procfs, and 783 * the parent is different (meaning the process was 784 * attached, rather than run as a child), then we need 785 * to give it back to the old parent, and send the 786 * parent the exit signal. The rest of the cleanup 787 * will be done when the old parent waits on the child. 788 */ 789 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 790 parent = p->p_opptr; 791 if (parent == NULL) 792 parent = initproc; 793 proc_reparent(p, parent); 794 p->p_opptr = NULL; 795 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 796 if (p->p_exitsig != 0) { 797 exit_psignal(p, parent, &ksi); 798 kpsignal(parent, &ksi, NULL); 799 } 800 wakeup(parent); 801 return; 802 } 803 804 scheduler_wait_hook(parent, p); 805 p->p_xstat = 0; 806 807 ruadd(&parent->p_stats->p_cru, p->p_ru); 808 809 /* 810 * At this point we are going to start freeing the final resources. 811 * If anyone tries to access the proc structure after here they 812 * will get a shock - bits are missing. 813 * Attempt to make it hard! 814 */ 815 816 p->p_stat = SIDL; /* not even a zombie any more */ 817 818 pool_put(&rusage_pool, p->p_ru); 819 820 /* 821 * Finally finished with old proc entry. 822 * Unlink it from its process group and free it. 823 */ 824 leavepgrp(p); 825 826 s = proclist_lock_write(); 827 LIST_REMOVE(p, p_list); /* off zombproc */ 828 p->p_pptr->p_nstopchild--; 829 LIST_REMOVE(p, p_sibling); 830 proclist_unlock_write(s); 831 832 /* 833 * Decrement the count of procs running with this uid. 834 */ 835 (void)chgproccnt(p->p_cred->p_ruid, -1); 836 837 /* 838 * Free up credentials. 839 */ 840 if (--p->p_cred->p_refcnt == 0) { 841 crfree(p->p_cred->pc_ucred); 842 pool_put(&pcred_pool, p->p_cred); 843 } 844 845 /* 846 * Release reference to text vnode 847 */ 848 if (p->p_textvp) 849 vrele(p->p_textvp); 850 851 /* Release any SA state. */ 852 if (p->p_sa) 853 sa_release(p); 854 855 /* Free proc structure and let pid be reallocated */ 856 proc_free_mem(p); 857 } 858 859 /* 860 * make process 'parent' the new parent of process 'child'. 861 * 862 * Must be called with proclist_lock_write() held. 863 */ 864 void 865 proc_reparent(struct proc *child, struct proc *parent) 866 { 867 868 if (child->p_pptr == parent) 869 return; 870 871 if (child->p_stat == SZOMB 872 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 873 child->p_pptr->p_nstopchild--; 874 parent->p_nstopchild++; 875 } 876 if (parent == initproc) 877 child->p_exitsig = SIGCHLD; 878 879 LIST_REMOVE(child, p_sibling); 880 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 881 child->p_pptr = parent; 882 } 883