1 /* $NetBSD: kern_exit.c,v 1.143 2004/10/01 16:30:52 yamt 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 1.143 2004/10/01 16:30:52 yamt 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); 269 270 doexithooks(p); 271 272 if (SESS_LEADER(p)) { 273 struct session *sp = p->p_session; 274 struct tty *tp; 275 276 if (sp->s_ttyvp) { 277 int s; 278 /* 279 * Controlling process. 280 * Signal foreground pgrp, 281 * drain controlling terminal 282 * and revoke access to controlling terminal. 283 */ 284 tp = sp->s_ttyp; 285 s = spltty(); 286 TTY_LOCK(tp); 287 if (tp->t_session == sp) { 288 if (tp->t_pgrp) 289 pgsignal(tp->t_pgrp, SIGHUP, 1); 290 /* we can't guarantee the revoke will do this */ 291 tp->t_pgrp = NULL; 292 tp->t_session = NULL; 293 TTY_UNLOCK(tp); 294 splx(s); 295 SESSRELE(sp); 296 (void) ttywait(tp); 297 /* 298 * The tty could have been revoked 299 * if we blocked. 300 */ 301 if (sp->s_ttyvp) 302 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 303 } else { 304 TTY_UNLOCK(tp); 305 splx(s); 306 } 307 if (sp->s_ttyvp) 308 vrele(sp->s_ttyvp); 309 sp->s_ttyvp = NULL; 310 /* 311 * s_ttyp is not zero'd; we use this to indicate 312 * that the session once had a controlling terminal. 313 * (for logging and informational purposes) 314 */ 315 } 316 sp->s_leader = NULL; 317 } 318 fixjobc(p, p->p_pgrp, 0); 319 (void)acct_process(p); 320 #ifdef KTRACE 321 /* 322 * release trace file 323 */ 324 ktrderef(p); 325 #endif 326 #ifdef SYSTRACE 327 systrace_sys_exit(p); 328 #endif 329 /* 330 * If emulation has process exit hook, call it now. 331 */ 332 if (p->p_emul->e_proc_exit) 333 (*p->p_emul->e_proc_exit)(p); 334 335 /* 336 * Free the VM resources we're still holding on to. 337 * We must do this from a valid thread because doing 338 * so may block. This frees vmspace, which we don't 339 * need anymore. The only remaining lwp is the one 340 * we run at this moment, nothing runs in userland 341 * anymore. 342 */ 343 uvm_proc_exit(p); 344 345 /* 346 * Give machine-dependent code a chance to free any 347 * MD LWP resources while we can still block. This must be done 348 * before uvm_lwp_exit(), in case these resources are in the 349 * PCB. 350 * THIS IS LAST BLOCKING OPERATION. 351 */ 352 #ifndef __NO_CPU_LWP_FREE 353 cpu_lwp_free(l, 1); 354 #endif 355 356 pmap_deactivate(l); 357 358 /* 359 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 360 */ 361 362 /* 363 * Save exit status and final rusage info, adding in child rusage 364 * info and self times. 365 * In order to pick up the time for the current execution, we must 366 * do this before unlinking the lwp from l_list. 367 */ 368 p->p_xstat = rv; 369 *p->p_ru = p->p_stats->p_ru; 370 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 371 ruadd(p->p_ru, &p->p_stats->p_cru); 372 373 /* 374 * Notify interested parties of our demise. 375 */ 376 KNOTE(&p->p_klist, NOTE_EXIT); 377 378 #if PERFCTRS 379 /* 380 * Save final PMC information in parent process & clean up. 381 */ 382 if (PMC_ENABLED(p)) { 383 pmc_save_context(p); 384 pmc_accumulate(p->p_pptr, p); 385 pmc_process_exit(p); 386 } 387 #endif 388 389 s = proclist_lock_write(); 390 /* 391 * Reset p_opptr pointer of all former children which got 392 * traced by another process and were reparented. We reset 393 * it to NULL here; the trace detach code then reparents 394 * the child to initproc. We only check allproc list, since 395 * eventual former children on zombproc list won't reference 396 * p_opptr anymore. 397 */ 398 if (p->p_flag & P_CHTRACED) { 399 PROCLIST_FOREACH(q, &allproc) { 400 if (q->p_opptr == p) 401 q->p_opptr = NULL; 402 } 403 } 404 405 /* 406 * Give orphaned children to init(8). 407 */ 408 q = LIST_FIRST(&p->p_children); 409 if (q) /* only need this if any child is SZOMB */ 410 wakeup(initproc); 411 for (; q != NULL; q = nq) { 412 nq = LIST_NEXT(q, p_sibling); 413 414 /* 415 * Traced processes are killed since their existence 416 * means someone is screwing up. Since we reset the 417 * trace flags, the logic in sys_wait4() would not be 418 * triggered to reparent the process to its 419 * original parent, so we must do this here. 420 */ 421 if (q->p_flag & P_TRACED) { 422 if (q->p_opptr != q->p_pptr) { 423 struct proc *t = q->p_opptr; 424 proc_reparent(q, t ? t : initproc); 425 q->p_opptr = NULL; 426 } else 427 proc_reparent(q, initproc); 428 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 429 psignal(q, SIGKILL); 430 } else { 431 proc_reparent(q, initproc); 432 } 433 } 434 435 /* 436 * Move proc from allproc to zombproc, it's now ready 437 * to be collected by parent. Remaining lwp resources 438 * will be freed in lwp_exit2() once we've switch to idle 439 * context. 440 * Changing the state to SZOMB stops it being found by pfind(). 441 */ 442 LIST_REMOVE(p, p_list); 443 LIST_INSERT_HEAD(&zombproc, p, p_list); 444 p->p_stat = SZOMB; 445 446 LIST_REMOVE(l, l_list); 447 LIST_REMOVE(l, l_sibling); 448 l->l_flag |= L_DETACHED|L_PROCEXIT; /* detached from proc too */ 449 l->l_stat = LSDEAD; 450 451 p->p_nrlwps--; 452 p->p_nlwps--; 453 454 /* Put in front of parent's sibling list for parent to collect it */ 455 q = p->p_pptr; 456 q->p_nstopchild++; 457 if (LIST_FIRST(&q->p_children) != p) { 458 /* Put child where it can be found quickly */ 459 LIST_REMOVE(p, p_sibling); 460 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 461 } 462 463 /* 464 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 465 * flag set, notify init instead (and hope it will handle 466 * this situation). 467 */ 468 if (q->p_flag & P_NOCLDWAIT) { 469 proc_reparent(p, initproc); 470 471 /* 472 * If this was the last child of our parent, notify 473 * parent, so in case he was wait(2)ing, he will 474 * continue. 475 */ 476 if (LIST_FIRST(&q->p_children) == NULL) 477 wakeup(q); 478 } 479 480 /* 481 * Clear curlwp after we've done all operations 482 * that could block, and before tearing down the rest 483 * of the process state that might be used from clock, etc. 484 * Also, can't clear curlwp while we're still runnable, 485 * as we're not on a run queue (we are current, just not 486 * a proper proc any longer!). 487 * 488 * Other substructures are freed from wait(). 489 */ 490 curlwp = NULL; 491 492 /* Delay release until after dropping the proclist lock */ 493 plim = p->p_limit; 494 pstats = p->p_stats; 495 ps = p->p_sigacts; 496 497 p->p_limit = NULL; 498 p->p_stats = NULL; 499 p->p_sigacts = NULL; 500 501 /* Reload parent pointer, since p may have been reparented above */ 502 q = p->p_pptr; 503 504 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) { 505 exit_psignal(p, q, &ksi); 506 do_psignal = 1; 507 } 508 509 /* 510 * Once we release the proclist lock, we shouldn't touch the 511 * process structure anymore, since it's now on the zombie 512 * list and available for collection by the parent. 513 */ 514 proclist_unlock_write(s); 515 516 if (do_psignal) 517 kpsignal(q, &ksi, NULL); 518 519 /* Wake up the parent so it can get exit status. */ 520 wakeup(q); 521 522 /* Release substructures */ 523 sigactsfree(ps); 524 limfree(plim); 525 pstatsfree(pstats); 526 527 #ifdef DEBUG 528 /* Nothing should use the process link anymore */ 529 l->l_proc = NULL; 530 #endif 531 532 /* This process no longer needs to hold the kernel lock. */ 533 KERNEL_PROC_UNLOCK(l); 534 535 /* 536 * Finally, call machine-dependent code to switch to a new 537 * context (possibly the idle context). Once we are no longer 538 * using the dead lwp's stack, lwp_exit2() will be called 539 * to arrange for the resources to be released. 540 * 541 * Note that cpu_exit() will end with a call equivalent to 542 * cpu_switch(), finishing our execution (pun intended). 543 */ 544 545 uvmexp.swtch++; 546 cpu_exit(l); 547 } 548 549 void 550 exit_lwps(struct lwp *l) 551 { 552 struct proc *p; 553 struct lwp *l2; 554 struct sadata_vp *vp; 555 int s, error; 556 lwpid_t waited; 557 558 p = l->l_proc; 559 560 /* XXX SMP 561 * This would be the right place to IPI any LWPs running on 562 * other processors so that they can notice the userret exit hook. 563 */ 564 p->p_userret = lwp_exit_hook; 565 p->p_userret_arg = NULL; 566 567 if (p->p_sa) { 568 SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { 569 /* 570 * Make SA-cached LWPs normal process runnable 571 * LWPs so that they'll also self-destruct. 572 */ 573 DPRINTF(("exit_lwps: Making cached LWPs of %d on VP %d runnable: ", 574 p->p_pid, vp->savp_id)); 575 SCHED_LOCK(s); 576 while ((l2 = sa_getcachelwp(vp)) != 0) { 577 l2->l_priority = l2->l_usrpri; 578 setrunnable(l2); 579 DPRINTF(("%d ", l2->l_lid)); 580 } 581 SCHED_UNLOCK(s); 582 DPRINTF(("\n")); 583 584 /* 585 * Clear wokenq, the LWPs on the queue will 586 * run below. 587 */ 588 vp->savp_wokenq_head = NULL; 589 } 590 } 591 592 /* 593 * Interrupt LWPs in interruptable sleep, unsuspend suspended 594 * LWPs, make detached LWPs undetached (so we can wait for 595 * them) and then wait for everyone else to finish. 596 */ 597 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 598 l2->l_flag &= ~(L_DETACHED|L_SA); 599 600 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 601 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 602 SCHED_LOCK(s); 603 setrunnable(l2); 604 SCHED_UNLOCK(s); 605 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 606 p->p_pid, l2->l_lid)); 607 } 608 } 609 610 611 while (p->p_nlwps > 1) { 612 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 613 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 614 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 615 if (error) 616 panic("exit_lwps: lwp_wait1 failed with error %d\n", 617 error); 618 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 619 } 620 621 p->p_userret = NULL; 622 } 623 624 /* Wrapper function for use in p_userret */ 625 static void 626 lwp_exit_hook(struct lwp *l, void *arg) 627 { 628 KERNEL_PROC_LOCK(l); 629 lwp_exit(l); 630 } 631 632 int 633 sys_wait4(struct lwp *l, void *v, register_t *retval) 634 { 635 struct sys_wait4_args /* { 636 syscallarg(int) pid; 637 syscallarg(int *) status; 638 syscallarg(int) options; 639 syscallarg(struct rusage *) rusage; 640 } */ *uap = v; 641 struct proc *child, *parent; 642 int status, error; 643 644 parent = l->l_proc; 645 646 if (SCARG(uap, pid) == 0) 647 SCARG(uap, pid) = -parent->p_pgid; 648 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 649 return (EINVAL); 650 651 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 652 &child); 653 if (error != 0) 654 return error; 655 if (child == NULL) { 656 *retval = 0; 657 return 0; 658 } 659 660 /* 661 * Collect child u-areas. 662 */ 663 uvm_uarea_drain(FALSE); 664 665 retval[0] = child->p_pid; 666 667 if (P_ZOMBIE(child)) { 668 if (SCARG(uap, status)) { 669 status = child->p_xstat; /* convert to int */ 670 error = copyout(&status, SCARG(uap, status), 671 sizeof(status)); 672 if (error) 673 return (error); 674 } 675 if (SCARG(uap, rusage)) { 676 error = copyout(child->p_ru, SCARG(uap, rusage), 677 sizeof(struct rusage)); 678 if (error) 679 return (error); 680 } 681 682 proc_free(child); 683 return 0; 684 } 685 686 /* child state must be SSTOP */ 687 if (SCARG(uap, status)) { 688 status = W_STOPCODE(child->p_xstat); 689 return copyout(&status, SCARG(uap, status), sizeof(status)); 690 } 691 return 0; 692 } 693 694 /* 695 * Scan list of child processes for a child process that has stopped or 696 * exited. Used by sys_wait4 and 'compat' equivalents. 697 */ 698 int 699 find_stopped_child(struct proc *parent, pid_t pid, int options, 700 struct proc **child_p) 701 { 702 struct proc *child; 703 int error; 704 705 for (;;) { 706 proclist_lock_read(); 707 error = ECHILD; 708 LIST_FOREACH(child, &parent->p_children, p_sibling) { 709 if (pid >= 0) { 710 if (child->p_pid != pid) { 711 child = p_find(pid, PFIND_ZOMBIE | 712 PFIND_LOCKED); 713 if (child == NULL 714 || child->p_pptr != parent) { 715 child = NULL; 716 break; 717 } 718 } 719 } else 720 if (pid != WAIT_ANY && child->p_pgid != -pid) 721 /* child not in correct pgrp */ 722 continue; 723 /* 724 * Wait for processes with p_exitsig != SIGCHLD 725 * processes only if WALTSIG is set; wait for 726 * processes with p_exitsig == SIGCHLD only 727 * if WALTSIG is clear. 728 */ 729 if (((options & WALLSIG) == 0) && 730 (options & WALTSIG ? child->p_exitsig == SIGCHLD 731 : P_EXITSIG(child) != SIGCHLD)){ 732 if (child->p_pid == pid) { 733 child = NULL; 734 break; 735 } 736 continue; 737 } 738 739 error = 0; 740 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 741 break; 742 743 if (child->p_stat == SSTOP && 744 (child->p_flag & P_WAITED) == 0 && 745 (child->p_flag & P_TRACED || options & WUNTRACED)) { 746 if ((options & WNOWAIT) == 0) { 747 child->p_flag |= P_WAITED; 748 parent->p_nstopchild--; 749 } 750 break; 751 } 752 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 753 child = NULL; 754 break; 755 } 756 } 757 proclist_unlock_read(); 758 if (child != NULL || error != 0 || options & WNOHANG) { 759 *child_p = child; 760 return error; 761 } 762 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 763 if (error != 0) 764 return error; 765 } 766 } 767 768 /* 769 * Free a process after parent has taken all the state info. 770 */ 771 void 772 proc_free(struct proc *p) 773 { 774 struct proc *parent = p->p_pptr; 775 ksiginfo_t ksi; 776 int s; 777 778 KASSERT(p->p_nlwps == 0); 779 KASSERT(p->p_nzlwps == 0); 780 KASSERT(p->p_nrlwps == 0); 781 KASSERT(LIST_EMPTY(&p->p_lwps)); 782 783 /* 784 * If we got the child via ptrace(2) or procfs, and 785 * the parent is different (meaning the process was 786 * attached, rather than run as a child), then we need 787 * to give it back to the old parent, and send the 788 * parent the exit signal. The rest of the cleanup 789 * will be done when the old parent waits on the child. 790 */ 791 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 792 parent = p->p_opptr; 793 if (parent == NULL) 794 parent = initproc; 795 proc_reparent(p, parent); 796 p->p_opptr = NULL; 797 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 798 if (p->p_exitsig != 0) { 799 exit_psignal(p, parent, &ksi); 800 kpsignal(parent, &ksi, NULL); 801 } 802 wakeup(parent); 803 return; 804 } 805 806 scheduler_wait_hook(parent, p); 807 p->p_xstat = 0; 808 809 ruadd(&parent->p_stats->p_cru, p->p_ru); 810 811 /* 812 * At this point we are going to start freeing the final resources. 813 * If anyone tries to access the proc structure after here they 814 * will get a shock - bits are missing. 815 * Attempt to make it hard! 816 */ 817 818 p->p_stat = SIDL; /* not even a zombie any more */ 819 820 pool_put(&rusage_pool, p->p_ru); 821 822 /* 823 * Finally finished with old proc entry. 824 * Unlink it from its process group and free it. 825 */ 826 leavepgrp(p); 827 828 s = proclist_lock_write(); 829 LIST_REMOVE(p, p_list); /* off zombproc */ 830 p->p_pptr->p_nstopchild--; 831 LIST_REMOVE(p, p_sibling); 832 proclist_unlock_write(s); 833 834 /* 835 * Decrement the count of procs running with this uid. 836 */ 837 (void)chgproccnt(p->p_cred->p_ruid, -1); 838 839 /* 840 * Free up credentials. 841 */ 842 if (--p->p_cred->p_refcnt == 0) { 843 crfree(p->p_cred->pc_ucred); 844 pool_put(&pcred_pool, p->p_cred); 845 } 846 847 /* 848 * Release reference to text vnode 849 */ 850 if (p->p_textvp) 851 vrele(p->p_textvp); 852 853 /* Release any SA state. */ 854 if (p->p_sa) 855 sa_release(p); 856 857 /* Free proc structure and let pid be reallocated */ 858 proc_free_mem(p); 859 } 860 861 /* 862 * make process 'parent' the new parent of process 'child'. 863 * 864 * Must be called with proclist_lock_write() held. 865 */ 866 void 867 proc_reparent(struct proc *child, struct proc *parent) 868 { 869 870 if (child->p_pptr == parent) 871 return; 872 873 if (child->p_stat == SZOMB 874 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 875 child->p_pptr->p_nstopchild--; 876 parent->p_nstopchild++; 877 } 878 if (parent == initproc) 879 child->p_exitsig = SIGCHLD; 880 881 LIST_REMOVE(child, p_sibling); 882 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 883 child->p_pptr = parent; 884 } 885