1 /* $NetBSD: kern_exit.c,v 1.127 2003/11/06 09:30:13 dsl 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 1.127 2003/11/06 09:30:13 dsl 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 static void exit_psignal(struct proc *, struct proc *); 132 133 /* 134 * Fill in the appropriate signal information, and kill the parent. 135 */ 136 static void 137 exit_psignal(struct proc *p, struct proc *pp) 138 { 139 ksiginfo_t ksi; 140 141 (void)memset(&ksi, 0, sizeof(ksi)); 142 if ((ksi.ksi_signo = P_EXITSIG(p)) == SIGCHLD) { 143 if (WIFSIGNALED(p->p_xstat)) { 144 if (WCOREDUMP(p->p_xstat)) 145 ksi.ksi_code = CLD_DUMPED; 146 else 147 ksi.ksi_code = CLD_KILLED; 148 } else { 149 ksi.ksi_code = CLD_EXITED; 150 } 151 } 152 /* 153 * we fill those in, even for non-SIGCHLD. 154 */ 155 ksi.ksi_pid = p->p_pid; 156 ksi.ksi_uid = p->p_ucred->cr_uid; 157 ksi.ksi_status = p->p_xstat; 158 /* XXX: is this still valid? */ 159 ksi.ksi_utime = p->p_ru->ru_utime.tv_sec; 160 ksi.ksi_stime = p->p_ru->ru_stime.tv_sec; 161 kpsignal(pp, &ksi, NULL); 162 } 163 164 /* 165 * exit -- 166 * Death of process. 167 */ 168 int 169 sys_exit(struct lwp *l, void *v, register_t *retval) 170 { 171 struct sys_exit_args /* { 172 syscallarg(int) rval; 173 } */ *uap = v; 174 175 /* Don't call exit1() multiple times in the same process.*/ 176 if (l->l_proc->p_flag & P_WEXIT) 177 lwp_exit(l); 178 179 exit1(l, W_EXITCODE(SCARG(uap, rval), 0)); 180 /* NOTREACHED */ 181 return (0); 182 } 183 184 /* 185 * Exit: deallocate address space and other resources, change proc state 186 * to zombie, and unlink proc from allproc and parent's lists. Save exit 187 * status and rusage for wait(). Check for child processes and orphan them. 188 */ 189 void 190 exit1(struct lwp *l, int rv) 191 { 192 struct proc *p, *q, *nq; 193 int s, sa; 194 195 p = l->l_proc; 196 197 if (__predict_false(p == initproc)) 198 panic("init died (signal %d, exit %d)", 199 WTERMSIG(rv), WEXITSTATUS(rv)); 200 201 p->p_flag |= P_WEXIT; 202 203 DPRINTF(("exit1: %d.%d exiting.\n", p->p_pid, l->l_lid)); 204 /* 205 * Disable scheduler activation upcalls. 206 * We're trying to get out of here. 207 */ 208 sa = 0; 209 if (p->p_sa != NULL) { 210 l->l_flag &= ~L_SA; 211 #if 0 212 p->p_flag &= ~P_SA; 213 #endif 214 sa = 1; 215 } 216 217 #ifdef PGINPROF 218 vmsizmon(); 219 #endif 220 if (p->p_flag & P_PROFIL) 221 stopprofclock(p); 222 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 223 /* 224 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 225 * wake up the parent early to avoid deadlock. 226 */ 227 if (p->p_flag & P_PPWAIT) { 228 p->p_flag &= ~P_PPWAIT; 229 wakeup(p->p_pptr); 230 } 231 sigfillset(&p->p_sigctx.ps_sigignore); 232 sigemptyset(&p->p_sigctx.ps_siglist); 233 p->p_sigctx.ps_sigcheck = 0; 234 timers_free(p, TIMERS_ALL); 235 236 if (sa || (p->p_nlwps > 1)) 237 exit_lwps(l); 238 239 #if defined(__HAVE_RAS) 240 ras_purgeall(p); 241 #endif 242 243 /* 244 * Close open files and release open-file table. 245 * This may block! 246 */ 247 fdfree(p); 248 cwdfree(p); 249 250 doexithooks(p); 251 252 if (SESS_LEADER(p)) { 253 struct session *sp = p->p_session; 254 struct tty *tp; 255 256 if (sp->s_ttyvp) { 257 /* 258 * Controlling process. 259 * Signal foreground pgrp, 260 * drain controlling terminal 261 * and revoke access to controlling terminal. 262 */ 263 tp = sp->s_ttyp; 264 TTY_LOCK(tp); 265 if (tp->t_session == sp) { 266 if (tp->t_pgrp) 267 pgsignal(tp->t_pgrp, SIGHUP, 1); 268 /* we can't guarantee the revoke will do this */ 269 tp->t_pgrp = NULL; 270 tp->t_session = NULL; 271 TTY_UNLOCK(tp); 272 SESSRELE(sp); 273 (void) ttywait(tp); 274 /* 275 * The tty could have been revoked 276 * if we blocked. 277 */ 278 if (sp->s_ttyvp) 279 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 280 } else 281 TTY_UNLOCK(tp); 282 if (sp->s_ttyvp) 283 vrele(sp->s_ttyvp); 284 sp->s_ttyvp = NULL; 285 /* 286 * s_ttyp is not zero'd; we use this to indicate 287 * that the session once had a controlling terminal. 288 * (for logging and informational purposes) 289 */ 290 } 291 sp->s_leader = NULL; 292 } 293 fixjobc(p, p->p_pgrp, 0); 294 (void)acct_process(p); 295 #ifdef KTRACE 296 /* 297 * release trace file 298 */ 299 ktrderef(p); 300 #endif 301 #ifdef SYSTRACE 302 systrace_sys_exit(p); 303 #endif 304 /* 305 * If emulation has process exit hook, call it now. 306 */ 307 if (p->p_emul->e_proc_exit) 308 (*p->p_emul->e_proc_exit)(p); 309 310 /* 311 * Give orphaned children to init(8). 312 */ 313 q = LIST_FIRST(&p->p_children); 314 if (q) /* only need this if any child is S_ZOMB */ 315 wakeup(initproc); 316 for (; q != 0; q = nq) { 317 nq = LIST_NEXT(q, p_sibling); 318 319 /* 320 * Traced processes are killed since their existence 321 * means someone is screwing up. Since we reset the 322 * trace flags, the logic in sys_wait4() would not be 323 * triggered to reparent the process to its 324 * original parent, so we must do this here. 325 */ 326 if (q->p_flag & P_TRACED) { 327 if (q->p_opptr != q->p_pptr) { 328 struct proc *t = q->p_opptr; 329 proc_reparent(q, t ? t : initproc); 330 q->p_opptr = NULL; 331 } else 332 proc_reparent(q, initproc); 333 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 334 psignal(q, SIGKILL); 335 } else { 336 proc_reparent(q, initproc); 337 } 338 } 339 340 /* 341 * Reset p_opptr pointer of all former children which got 342 * traced by another process and were reparented. We reset 343 * it to NULL here; the trace detach code then reparents 344 * the child to initproc. We only check allproc list, since 345 * eventual former children on zombproc list won't reference 346 * p_opptr anymore. 347 */ 348 if (p->p_flag & P_CHTRACED) { 349 struct proc *t; 350 351 proclist_lock_read(); 352 353 LIST_FOREACH(t, &allproc, p_list) { 354 if (t->p_opptr == p) 355 t->p_opptr = NULL; 356 } 357 358 proclist_unlock_read(); 359 } 360 361 /* 362 * Save exit status and final rusage info, adding in child rusage 363 * info and self times. 364 * In order to pick up the time for the current execution, we must 365 * do this before unlinking the lwp from l_list. 366 */ 367 p->p_xstat = rv; 368 *p->p_ru = p->p_stats->p_ru; 369 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 370 ruadd(p->p_ru, &p->p_stats->p_cru); 371 372 /* 373 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 374 */ 375 376 /* 377 * Move proc from allproc to zombproc, but do not yet 378 * wake up the reaper. We will put the proc on the 379 * deadproc list later (using the p_dead member), and 380 * wake up the reaper when we do. 381 * Changing the state to SDEAD stops it being found by pfind(). 382 */ 383 s = proclist_lock_write(); 384 p->p_stat = SDEAD; 385 p->p_nrlwps--; 386 l->l_stat = LSDEAD; 387 LIST_REMOVE(p, p_list); 388 LIST_INSERT_HEAD(&zombproc, p, p_list); 389 LIST_REMOVE(l, l_list); 390 l->l_flag |= L_DETACHED; 391 proclist_unlock_write(s); 392 393 /* 394 * Notify interested parties of our demise. 395 */ 396 KNOTE(&p->p_klist, NOTE_EXIT); 397 398 #if PERFCTRS 399 /* 400 * Save final PMC information in parent process & clean up. 401 */ 402 if (PMC_ENABLED(p)) { 403 pmc_save_context(p); 404 pmc_accumulate(p->p_pptr, p); 405 pmc_process_exit(p); 406 } 407 #endif 408 409 /* 410 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 411 * flag set, notify init instead (and hope it will handle 412 * this situation). 413 */ 414 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 415 struct proc *pp = p->p_pptr; 416 proc_reparent(p, initproc); 417 /* 418 * If this was the last child of our parent, notify 419 * parent, so in case he was wait(2)ing, he will 420 * continue. 421 */ 422 if (LIST_FIRST(&pp->p_children) == NULL) 423 wakeup(pp); 424 } 425 426 /* 427 * Release the process's signal state. 428 */ 429 sigactsfree(p); 430 431 /* 432 * Clear curlwp after we've done all operations 433 * that could block, and before tearing down the rest 434 * of the process state that might be used from clock, etc. 435 * Also, can't clear curlwp while we're still runnable, 436 * as we're not on a run queue (we are current, just not 437 * a proper proc any longer!). 438 * 439 * Other substructures are freed from wait(). 440 */ 441 curlwp = NULL; 442 limfree(p->p_limit); 443 pstatsfree(p->p_stats); 444 p->p_limit = NULL; 445 446 /* This process no longer needs to hold the kernel lock. */ 447 KERNEL_PROC_UNLOCK(l); 448 449 /* 450 * Finally, call machine-dependent code to switch to a new 451 * context (possibly the idle context). Once we are no longer 452 * using the dead process's vmspace and stack, exit2() will be 453 * called to schedule those resources to be released by the 454 * reaper thread. 455 * 456 * Note that cpu_exit() will end with a call equivalent to 457 * cpu_switch(), finishing our execution (pun intended). 458 */ 459 460 cpu_exit(l, 1); 461 } 462 463 void 464 exit_lwps(struct lwp *l) 465 { 466 struct proc *p; 467 struct lwp *l2; 468 int s, error; 469 lwpid_t waited; 470 471 p = l->l_proc; 472 473 /* XXX SMP 474 * This would be the right place to IPI any LWPs running on 475 * other processors so that they can notice the userret exit hook. 476 */ 477 p->p_userret = lwp_exit_hook; 478 p->p_userret_arg = NULL; 479 480 /* 481 * Make SA-cached LWPs normal process runnable LWPs so that 482 * they'll also self-destruct. 483 */ 484 if (p->p_sa && p->p_sa->sa_ncached > 0) { 485 DPRINTF(("exit_lwps: Making cached LWPs of %d runnable: ", 486 p->p_pid)); 487 SCHED_LOCK(s); 488 while ((l2 = sa_getcachelwp(p)) != 0) { 489 l2->l_priority = l2->l_usrpri; 490 setrunnable(l2); 491 DPRINTF(("%d ", l2->l_lid)); 492 } 493 DPRINTF(("\n")); 494 SCHED_UNLOCK(s); 495 } 496 497 /* 498 * Interrupt LWPs in interruptable sleep, unsuspend suspended 499 * LWPs, make detached LWPs undetached (so we can wait for 500 * them) and then wait for everyone else to finish. 501 */ 502 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 503 l2->l_flag &= ~(L_DETACHED|L_SA); 504 505 if (l2->l_wchan == &l2->l_upcallstack) 506 wakeup(&l2->l_upcallstack); 507 508 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 509 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 510 SCHED_LOCK(s); 511 setrunnable(l2); 512 SCHED_UNLOCK(s); 513 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 514 p->p_pid, l2->l_lid)); 515 } 516 } 517 518 519 while (p->p_nlwps > 1) { 520 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 521 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 522 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 523 if (error) 524 panic("exit_lwps: lwp_wait1 failed with error %d\n", 525 error); 526 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 527 } 528 529 p->p_userret = NULL; 530 } 531 532 /* Wrapper function for use in p_userret */ 533 static void 534 lwp_exit_hook(struct lwp *l, void *arg) 535 { 536 KERNEL_PROC_LOCK(l); 537 lwp_exit(l); 538 } 539 540 /* 541 * We are called from cpu_exit() once it is safe to schedule the 542 * dead process's resources to be freed (i.e., once we've switched to 543 * the idle PCB for the current CPU). 544 * 545 * NOTE: One must be careful with locking in this routine. It's 546 * called from a critical section in machine-dependent code, so 547 * we should refrain from changing any interrupt state. 548 * 549 * We lock the deadproc list (a spin lock), place the proc on that 550 * list (using the p_dead member), and wake up the reaper. 551 */ 552 void 553 exit2(struct lwp *l) 554 { 555 struct proc *p = l->l_proc; 556 557 simple_lock(&deadproc_slock); 558 SLIST_INSERT_HEAD(&deadprocs, p, p_dead); 559 simple_unlock(&deadproc_slock); 560 561 /* lwp_exit2() will wake up deadproc for us. */ 562 lwp_exit2(l); 563 } 564 565 /* 566 * Process reaper. This is run by a kernel thread to free the resources 567 * of a dead process. Once the resources are free, the process becomes 568 * a zombie, and the parent is allowed to read the undead's status. 569 */ 570 void 571 reaper(void *arg) 572 { 573 struct proc *p; 574 struct lwp *l; 575 576 KERNEL_PROC_UNLOCK(curlwp); 577 578 for (;;) { 579 simple_lock(&deadproc_slock); 580 p = SLIST_FIRST(&deadprocs); 581 l = LIST_FIRST(&deadlwp); 582 if (p == NULL && l == NULL) { 583 /* No work for us; go to sleep until someone exits. */ 584 (void) ltsleep(&deadprocs, PVM|PNORELOCK, 585 "reaper", 0, &deadproc_slock); 586 continue; 587 } 588 589 if (l != NULL ) { 590 p = l->l_proc; 591 592 /* Remove lwp from the deadlwp list. */ 593 LIST_REMOVE(l, l_list); 594 simple_unlock(&deadproc_slock); 595 KERNEL_PROC_LOCK(curlwp); 596 597 /* 598 * Give machine-dependent code a chance to free any 599 * resources it couldn't free while still running on 600 * that process's context. This must be done before 601 * uvm_lwp_exit(), in case these resources are in the 602 * PCB. 603 */ 604 cpu_wait(l); 605 606 /* 607 * Free the VM resources we're still holding on to. 608 */ 609 uvm_lwp_exit(l); 610 611 l->l_stat = LSZOMB; 612 if (l->l_flag & L_DETACHED) { 613 /* Nobody waits for detached LWPs. */ 614 LIST_REMOVE(l, l_sibling); 615 p->p_nlwps--; 616 pool_put(&lwp_pool, l); 617 } else { 618 p->p_nzlwps++; 619 wakeup(&p->p_nlwps); 620 } 621 /* XXXNJW where should this be with respect to 622 * the wakeup() above? */ 623 KERNEL_PROC_UNLOCK(curlwp); 624 } else { 625 /* Remove proc from the deadproc list. */ 626 SLIST_REMOVE_HEAD(&deadprocs, p_dead); 627 simple_unlock(&deadproc_slock); 628 KERNEL_PROC_LOCK(curlwp); 629 630 /* 631 * Free the VM resources we're still holding on to. 632 * We must do this from a valid thread because doing 633 * so may block. 634 */ 635 uvm_proc_exit(p); 636 637 /* Process is now a true zombie. */ 638 p->p_stat = SZOMB; 639 640 /* Wake up the parent so it can get exit status. */ 641 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 642 exit_psignal(p, p->p_pptr); 643 KERNEL_PROC_UNLOCK(curlwp); 644 wakeup(p->p_pptr); 645 } 646 } 647 } 648 649 int 650 sys_wait4(struct lwp *l, void *v, register_t *retval) 651 { 652 struct sys_wait4_args /* { 653 syscallarg(int) pid; 654 syscallarg(int *) status; 655 syscallarg(int) options; 656 syscallarg(struct rusage *) rusage; 657 } */ *uap = v; 658 struct proc *child, *parent; 659 int status, error; 660 661 parent = l->l_proc; 662 663 if (SCARG(uap, pid) == 0) 664 SCARG(uap, pid) = -parent->p_pgid; 665 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 666 return (EINVAL); 667 668 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 669 &child); 670 if (error != 0) 671 return error; 672 if (child == NULL) { 673 *retval = 0; 674 return 0; 675 } 676 677 retval[0] = child->p_pid; 678 679 if (child->p_stat == SZOMB) { 680 if (SCARG(uap, status)) { 681 status = child->p_xstat; /* convert to int */ 682 error = copyout(&status, SCARG(uap, status), 683 sizeof(status)); 684 if (error) 685 return (error); 686 } 687 if (SCARG(uap, rusage)) { 688 error = copyout(child->p_ru, SCARG(uap, rusage), 689 sizeof(struct rusage)); 690 if (error) 691 return (error); 692 } 693 694 proc_free(child); 695 return 0; 696 } 697 698 /* child state must be SSTOP */ 699 if (SCARG(uap, status)) { 700 status = W_STOPCODE(child->p_xstat); 701 return copyout(&status, SCARG(uap, status), sizeof (status)); 702 } 703 return 0; 704 } 705 706 /* 707 * Scan list of child processes for a child process that has stopped or 708 * exited. Used by sys_wait4 and 'compat' equivalents. 709 */ 710 int 711 find_stopped_child(struct proc *parent, pid_t pid, int options, 712 struct proc **child_p) 713 { 714 struct proc *child; 715 int c_found, error; 716 717 for (;;) { 718 c_found = 0; 719 LIST_FOREACH(child, &parent->p_children, p_sibling) { 720 if (pid != WAIT_ANY && 721 child->p_pid != pid && 722 child->p_pgid != -pid) 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 continue; 734 735 c_found = 1; 736 if (child->p_stat == SZOMB && 737 (options & WNOZOMBIE) == 0) { 738 *child_p = child; 739 return 0; 740 } 741 742 if (child->p_stat == SSTOP && 743 (child->p_flag & P_WAITED) == 0 && 744 (child->p_flag & P_TRACED || options & WUNTRACED)) { 745 if ((options & WNOWAIT) == 0) 746 child->p_flag |= P_WAITED; 747 *child_p = child; 748 return 0; 749 } 750 } 751 if (c_found == 0) 752 return ECHILD; 753 if (options & WNOHANG) { 754 *child_p = NULL; 755 return 0; 756 } 757 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 758 if (error != 0) 759 return error; 760 } 761 } 762 763 /* 764 * Free a process after parent has taken all the state info. 765 */ 766 void 767 proc_free(struct proc *p) 768 { 769 struct proc *parent = p->p_pptr; 770 int s; 771 772 /* 773 * If we got the child via ptrace(2) or procfs, and 774 * the parent is different (meaning the process was 775 * attached, rather than run as a child), then we need 776 * to give it back to the old parent, and send the 777 * parent the exit signal. The rest of the cleanup 778 * will be done when the old parent waits on the child. 779 */ 780 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 781 parent = p->p_opptr; 782 if (parent == NULL) 783 parent = initproc; 784 proc_reparent(p, parent); 785 p->p_opptr = NULL; 786 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 787 if (p->p_exitsig != 0) 788 exit_psignal(p, parent); 789 wakeup(parent); 790 return; 791 } 792 793 scheduler_wait_hook(parent, p); 794 p->p_xstat = 0; 795 796 ruadd(&parent->p_stats->p_cru, p->p_ru); 797 798 /* 799 * At this point we are going to start freeing the final resources. 800 * If anyone tries to access the proc structure after here they 801 * will get a shock - bits are missing. 802 * Attempt to make it hard! 803 */ 804 805 p->p_stat = SIDL; /* not even a zombie any more */ 806 807 pool_put(&rusage_pool, p->p_ru); 808 809 /* 810 * Finally finished with old proc entry. 811 * Unlink it from its process group and free it. 812 */ 813 leavepgrp(p); 814 815 s = proclist_lock_write(); 816 LIST_REMOVE(p, p_list); /* off zombproc */ 817 LIST_REMOVE(p, p_sibling); 818 proclist_unlock_write(s); 819 820 /* 821 * Decrement the count of procs running with this uid. 822 */ 823 (void)chgproccnt(p->p_cred->p_ruid, -1); 824 825 /* 826 * Free up credentials. 827 */ 828 if (--p->p_cred->p_refcnt == 0) { 829 crfree(p->p_cred->pc_ucred); 830 pool_put(&pcred_pool, p->p_cred); 831 } 832 833 /* 834 * Release reference to text vnode 835 */ 836 if (p->p_textvp) 837 vrele(p->p_textvp); 838 839 /* 840 * Release any SA state 841 */ 842 if (p->p_sa) { 843 free(p->p_sa->sa_stacks, M_SA); 844 pool_put(&sadata_pool, p->p_sa); 845 } 846 847 /* Free proc structure and let pid be reallocated */ 848 proc_free_mem(p); 849 } 850 851 /* 852 * make process 'parent' the new parent of process 'child'. 853 */ 854 void 855 proc_reparent(struct proc *child, struct proc *parent) 856 { 857 858 if (child->p_pptr == parent) 859 return; 860 861 if (parent == initproc) 862 child->p_exitsig = SIGCHLD; 863 864 LIST_REMOVE(child, p_sibling); 865 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 866 child->p_pptr = parent; 867 } 868