1 /* $NetBSD: kern_exit.c,v 1.124 2003/09/16 13:46:24 cl 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 1.124 2003/09/16 13:46:24 cl 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((caddr_t)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; 254 255 if (sp->s_ttyvp) { 256 /* 257 * Controlling process. 258 * Signal foreground pgrp, 259 * drain controlling terminal 260 * and revoke access to controlling terminal. 261 */ 262 if (sp->s_ttyp->t_session == sp) { 263 if (sp->s_ttyp->t_pgrp) 264 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 265 (void) ttywait(sp->s_ttyp); 266 /* 267 * The tty could have been revoked 268 * if we blocked. 269 */ 270 if (sp->s_ttyvp) 271 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 272 } 273 if (sp->s_ttyvp) 274 vrele(sp->s_ttyvp); 275 sp->s_ttyvp = NULL; 276 /* 277 * s_ttyp is not zero'd; we use this to indicate 278 * that the session once had a controlling terminal. 279 * (for logging and informational purposes) 280 */ 281 } 282 sp->s_leader = NULL; 283 } 284 fixjobc(p, p->p_pgrp, 0); 285 (void)acct_process(p); 286 #ifdef KTRACE 287 /* 288 * release trace file 289 */ 290 ktrderef(p); 291 #endif 292 #ifdef SYSTRACE 293 systrace_sys_exit(p); 294 #endif 295 /* 296 * If emulation has process exit hook, call it now. 297 */ 298 if (p->p_emul->e_proc_exit) 299 (*p->p_emul->e_proc_exit)(p); 300 301 /* 302 * Give orphaned children to init(8). 303 */ 304 q = LIST_FIRST(&p->p_children); 305 if (q) /* only need this if any child is S_ZOMB */ 306 wakeup((caddr_t)initproc); 307 for (; q != 0; q = nq) { 308 nq = LIST_NEXT(q, p_sibling); 309 310 /* 311 * Traced processes are killed since their existence 312 * means someone is screwing up. Since we reset the 313 * trace flags, the logic in sys_wait4() would not be 314 * triggered to reparent the process to its 315 * original parent, so we must do this here. 316 */ 317 if (q->p_flag & P_TRACED) { 318 if (q->p_opptr != q->p_pptr) { 319 struct proc *t = q->p_opptr; 320 proc_reparent(q, t ? t : initproc); 321 q->p_opptr = NULL; 322 } else 323 proc_reparent(q, initproc); 324 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 325 psignal(q, SIGKILL); 326 } else { 327 proc_reparent(q, initproc); 328 } 329 } 330 331 /* 332 * Reset p_opptr pointer of all former children which got 333 * traced by another process and were reparented. We reset 334 * it to NULL here; the trace detach code then reparents 335 * the child to initproc. We only check allproc list, since 336 * eventual former children on zombproc list won't reference 337 * p_opptr anymore. 338 */ 339 if (p->p_flag & P_CHTRACED) { 340 struct proc *t; 341 342 proclist_lock_read(); 343 344 LIST_FOREACH(t, &allproc, p_list) { 345 if (t->p_opptr == p) 346 t->p_opptr = NULL; 347 } 348 349 proclist_unlock_read(); 350 } 351 352 /* 353 * Save exit status and final rusage info, adding in child rusage 354 * info and self times. 355 * In order to pick up the time for the current execution, we must 356 * do this before unlinking the lwp from l_list. 357 */ 358 p->p_xstat = rv; 359 *p->p_ru = p->p_stats->p_ru; 360 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 361 ruadd(p->p_ru, &p->p_stats->p_cru); 362 363 /* 364 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 365 */ 366 367 /* 368 * Move proc from allproc to zombproc, but do not yet 369 * wake up the reaper. We will put the proc on the 370 * deadproc list later (using the p_dead member), and 371 * wake up the reaper when we do. 372 * Changing the state to SDEAD stops it being found by pfind(). 373 */ 374 s = proclist_lock_write(); 375 p->p_stat = SDEAD; 376 p->p_nrlwps--; 377 l->l_stat = LSDEAD; 378 LIST_REMOVE(p, p_list); 379 LIST_INSERT_HEAD(&zombproc, p, p_list); 380 LIST_REMOVE(l, l_list); 381 l->l_flag |= L_DETACHED; 382 proclist_unlock_write(s); 383 384 /* 385 * Notify interested parties of our demise. 386 */ 387 KNOTE(&p->p_klist, NOTE_EXIT); 388 389 #if PERFCTRS 390 /* 391 * Save final PMC information in parent process & clean up. 392 */ 393 if (PMC_ENABLED(p)) { 394 pmc_save_context(p); 395 pmc_accumulate(p->p_pptr, p); 396 pmc_process_exit(p); 397 } 398 #endif 399 400 /* 401 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 402 * flag set, notify init instead (and hope it will handle 403 * this situation). 404 */ 405 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 406 struct proc *pp = p->p_pptr; 407 proc_reparent(p, initproc); 408 /* 409 * If this was the last child of our parent, notify 410 * parent, so in case he was wait(2)ing, he will 411 * continue. 412 */ 413 if (LIST_FIRST(&pp->p_children) == NULL) 414 wakeup((caddr_t)pp); 415 } 416 417 /* 418 * Release the process's signal state. 419 */ 420 sigactsfree(p); 421 422 /* 423 * Clear curlwp after we've done all operations 424 * that could block, and before tearing down the rest 425 * of the process state that might be used from clock, etc. 426 * Also, can't clear curlwp while we're still runnable, 427 * as we're not on a run queue (we are current, just not 428 * a proper proc any longer!). 429 * 430 * Other substructures are freed from wait(). 431 */ 432 curlwp = NULL; 433 limfree(p->p_limit); 434 pstatsfree(p->p_stats); 435 p->p_limit = NULL; 436 437 /* This process no longer needs to hold the kernel lock. */ 438 KERNEL_PROC_UNLOCK(l); 439 440 /* 441 * Finally, call machine-dependent code to switch to a new 442 * context (possibly the idle context). Once we are no longer 443 * using the dead process's vmspace and stack, exit2() will be 444 * called to schedule those resources to be released by the 445 * reaper thread. 446 * 447 * Note that cpu_exit() will end with a call equivalent to 448 * cpu_switch(), finishing our execution (pun intended). 449 */ 450 451 cpu_exit(l, 1); 452 } 453 454 void 455 exit_lwps(struct lwp *l) 456 { 457 struct proc *p; 458 struct lwp *l2; 459 int s, error; 460 lwpid_t waited; 461 462 p = l->l_proc; 463 464 /* XXX SMP 465 * This would be the right place to IPI any LWPs running on 466 * other processors so that they can notice the userret exit hook. 467 */ 468 p->p_userret = lwp_exit_hook; 469 p->p_userret_arg = NULL; 470 471 /* 472 * Make SA-cached LWPs normal process runnable LWPs so that 473 * they'll also self-destruct. 474 */ 475 if (p->p_sa && p->p_sa->sa_ncached > 0) { 476 DPRINTF(("exit_lwps: Making cached LWPs of %d runnable: ", 477 p->p_pid)); 478 SCHED_LOCK(s); 479 while ((l2 = sa_getcachelwp(p)) != 0) { 480 l2->l_priority = l2->l_usrpri; 481 setrunnable(l2); 482 DPRINTF(("%d ", l2->l_lid)); 483 } 484 DPRINTF(("\n")); 485 SCHED_UNLOCK(s); 486 } 487 488 /* 489 * Interrupt LWPs in interruptable sleep, unsuspend suspended 490 * LWPs, make detached LWPs undetached (so we can wait for 491 * them) and then wait for everyone else to finish. 492 */ 493 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 494 #if 0 495 l2->l_flag &= ~(L_DETACHED|L_SA); 496 #endif 497 l2->l_flag &= ~(L_DETACHED); 498 499 if(l2->l_flag & L_SA_WANTS_VP) 500 wakeup(l2); 501 502 if (l2->l_wchan == &l2->l_upcallstack) 503 wakeup(&l2->l_upcallstack); 504 505 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 506 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 507 SCHED_LOCK(s); 508 setrunnable(l2); 509 SCHED_UNLOCK(s); 510 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 511 p->p_pid, l2->l_lid)); 512 } 513 } 514 515 516 while (p->p_nlwps > 1) { 517 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 518 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 519 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 520 if (error) 521 panic("exit_lwps: lwp_wait1 failed with error %d\n", 522 error); 523 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 524 } 525 526 p->p_userret = NULL; 527 } 528 529 /* Wrapper function for use in p_userret */ 530 static void 531 lwp_exit_hook(struct lwp *l, void *arg) 532 { 533 KERNEL_PROC_LOCK(l); 534 lwp_exit(l); 535 } 536 537 /* 538 * We are called from cpu_exit() once it is safe to schedule the 539 * dead process's resources to be freed (i.e., once we've switched to 540 * the idle PCB for the current CPU). 541 * 542 * NOTE: One must be careful with locking in this routine. It's 543 * called from a critical section in machine-dependent code, so 544 * we should refrain from changing any interrupt state. 545 * 546 * We lock the deadproc list (a spin lock), place the proc on that 547 * list (using the p_dead member), and wake up the reaper. 548 */ 549 void 550 exit2(struct lwp *l) 551 { 552 struct proc *p = l->l_proc; 553 554 simple_lock(&deadproc_slock); 555 SLIST_INSERT_HEAD(&deadprocs, p, p_dead); 556 simple_unlock(&deadproc_slock); 557 558 /* lwp_exit2() will wake up deadproc for us. */ 559 lwp_exit2(l); 560 } 561 562 /* 563 * Process reaper. This is run by a kernel thread to free the resources 564 * of a dead process. Once the resources are free, the process becomes 565 * a zombie, and the parent is allowed to read the undead's status. 566 */ 567 void 568 reaper(void *arg) 569 { 570 struct proc *p; 571 struct lwp *l; 572 573 KERNEL_PROC_UNLOCK(curlwp); 574 575 for (;;) { 576 simple_lock(&deadproc_slock); 577 p = SLIST_FIRST(&deadprocs); 578 l = LIST_FIRST(&deadlwp); 579 if (p == NULL && l == NULL) { 580 /* No work for us; go to sleep until someone exits. */ 581 (void) ltsleep(&deadprocs, PVM|PNORELOCK, 582 "reaper", 0, &deadproc_slock); 583 continue; 584 } 585 586 if (l != NULL ) { 587 p = l->l_proc; 588 589 /* Remove lwp from the deadlwp list. */ 590 LIST_REMOVE(l, l_list); 591 simple_unlock(&deadproc_slock); 592 KERNEL_PROC_LOCK(curlwp); 593 594 /* 595 * Give machine-dependent code a chance to free any 596 * resources it couldn't free while still running on 597 * that process's context. This must be done before 598 * uvm_lwp_exit(), in case these resources are in the 599 * PCB. 600 */ 601 cpu_wait(l); 602 603 /* 604 * Free the VM resources we're still holding on to. 605 */ 606 uvm_lwp_exit(l); 607 608 l->l_stat = LSZOMB; 609 if (l->l_flag & L_DETACHED) { 610 /* Nobody waits for detached LWPs. */ 611 LIST_REMOVE(l, l_sibling); 612 p->p_nlwps--; 613 pool_put(&lwp_pool, l); 614 } else { 615 p->p_nzlwps++; 616 wakeup((caddr_t)&p->p_nlwps); 617 } 618 /* XXXNJW where should this be with respect to 619 * the wakeup() above? */ 620 KERNEL_PROC_UNLOCK(curlwp); 621 } else { 622 /* Remove proc from the deadproc list. */ 623 SLIST_REMOVE_HEAD(&deadprocs, p_dead); 624 simple_unlock(&deadproc_slock); 625 KERNEL_PROC_LOCK(curlwp); 626 627 /* 628 * Free the VM resources we're still holding on to. 629 * We must do this from a valid thread because doing 630 * so may block. 631 */ 632 uvm_proc_exit(p); 633 634 /* Process is now a true zombie. */ 635 p->p_stat = SZOMB; 636 637 /* Wake up the parent so it can get exit status. */ 638 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 639 exit_psignal(p, p->p_pptr); 640 KERNEL_PROC_UNLOCK(curlwp); 641 wakeup((caddr_t)p->p_pptr); 642 } 643 } 644 } 645 646 int 647 sys_wait4(struct lwp *l, void *v, register_t *retval) 648 { 649 struct sys_wait4_args /* { 650 syscallarg(int) pid; 651 syscallarg(int *) status; 652 syscallarg(int) options; 653 syscallarg(struct rusage *) rusage; 654 } */ *uap = v; 655 struct proc *child, *parent; 656 int status, error; 657 658 parent = l->l_proc; 659 660 if (SCARG(uap, pid) == 0) 661 SCARG(uap, pid) = -parent->p_pgid; 662 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 663 return (EINVAL); 664 665 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 666 &child); 667 if (error != 0) 668 return error; 669 if (child == NULL) { 670 *retval = 0; 671 return 0; 672 } 673 674 retval[0] = child->p_pid; 675 676 if (child->p_stat == SZOMB) { 677 if (SCARG(uap, status)) { 678 status = child->p_xstat; /* convert to int */ 679 error = copyout((caddr_t)&status, 680 (caddr_t)SCARG(uap, status), 681 sizeof(status)); 682 if (error) 683 return (error); 684 } 685 if (SCARG(uap, rusage)) { 686 error = copyout((caddr_t)child->p_ru, 687 (caddr_t)SCARG(uap, rusage), 688 sizeof(struct rusage)); 689 if (error) 690 return (error); 691 } 692 693 proc_free(child); 694 return 0; 695 } 696 697 /* child state must be SSTOP */ 698 if (SCARG(uap, status)) { 699 status = W_STOPCODE(child->p_xstat); 700 return copyout((caddr_t)&status, 701 (caddr_t)SCARG(uap, status), 702 sizeof(status)); 703 } 704 return 0; 705 } 706 707 /* 708 * Scan list of child processes for a child process that has stopped or 709 * exited. Used by sys_wait4 and 'compat' equivalents. 710 */ 711 int 712 find_stopped_child(struct proc *parent, pid_t pid, int options, 713 struct proc **child_p) 714 { 715 struct proc *child; 716 int c_found, error; 717 718 for (;;) { 719 c_found = 0; 720 LIST_FOREACH(child, &parent->p_children, p_sibling) { 721 if (pid != WAIT_ANY && 722 child->p_pid != pid && 723 child->p_pgid != -pid) 724 continue; 725 /* 726 * Wait for processes with p_exitsig != SIGCHLD 727 * processes only if WALTSIG is set; wait for 728 * processes with p_exitsig == SIGCHLD only 729 * if WALTSIG is clear. 730 */ 731 if (((options & WALLSIG) == 0) && 732 (options & WALTSIG ? child->p_exitsig == SIGCHLD 733 : P_EXITSIG(child) != SIGCHLD)) 734 continue; 735 736 c_found = 1; 737 if (child->p_stat == SZOMB && 738 (options & WNOZOMBIE) == 0) { 739 *child_p = child; 740 return 0; 741 } 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 *child_p = child; 749 return 0; 750 } 751 } 752 if (c_found == 0) 753 return ECHILD; 754 if (options & WNOHANG) { 755 *child_p = NULL; 756 return 0; 757 } 758 error = tsleep((caddr_t)parent, PWAIT | PCATCH, "wait", 0); 759 if (error != 0) 760 return error; 761 } 762 } 763 764 /* 765 * Free a process after parent has taken all the state info. 766 */ 767 void 768 proc_free(struct proc *p) 769 { 770 struct proc *parent = p->p_pptr; 771 int s; 772 773 /* 774 * If we got the child via ptrace(2) or procfs, and 775 * the parent is different (meaning the process was 776 * attached, rather than run as a child), then we need 777 * to give it back to the old parent, and send the 778 * parent the exit signal. The rest of the cleanup 779 * will be done when the old parent waits on the child. 780 */ 781 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 782 parent = p->p_opptr; 783 if (parent == NULL) 784 parent = initproc; 785 proc_reparent(p, parent); 786 p->p_opptr = NULL; 787 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 788 if (p->p_exitsig != 0) 789 exit_psignal(p, parent); 790 wakeup((caddr_t)parent); 791 return; 792 } 793 794 scheduler_wait_hook(parent, p); 795 p->p_xstat = 0; 796 797 ruadd(&parent->p_stats->p_cru, p->p_ru); 798 799 /* 800 * At this point we are going to start freeing the final resources. 801 * If anyone tries to access the proc structure after here they 802 * will get a shock - bits are missing. 803 * Attempt to make it hard! 804 */ 805 806 p->p_stat = SIDL; /* not even a zombie any more */ 807 808 pool_put(&rusage_pool, p->p_ru); 809 810 /* 811 * Finally finished with old proc entry. 812 * Unlink it from its process group and free it. 813 */ 814 leavepgrp(p); 815 816 s = proclist_lock_write(); 817 LIST_REMOVE(p, p_list); /* off zombproc */ 818 LIST_REMOVE(p, p_sibling); 819 proclist_unlock_write(s); 820 821 /* 822 * Decrement the count of procs running with this uid. 823 */ 824 (void)chgproccnt(p->p_cred->p_ruid, -1); 825 826 /* 827 * Free up credentials. 828 */ 829 if (--p->p_cred->p_refcnt == 0) { 830 crfree(p->p_cred->pc_ucred); 831 pool_put(&pcred_pool, p->p_cred); 832 } 833 834 /* 835 * Release reference to text vnode 836 */ 837 if (p->p_textvp) 838 vrele(p->p_textvp); 839 840 /* 841 * Release any SA state 842 */ 843 if (p->p_sa) { 844 free(p->p_sa->sa_stacks, M_SA); 845 pool_put(&sadata_pool, p->p_sa); 846 } 847 848 /* Free proc structure and let pid be reallocated */ 849 proc_free_mem(p); 850 } 851 852 /* 853 * make process 'parent' the new parent of process 'child'. 854 */ 855 void 856 proc_reparent(struct proc *child, struct proc *parent) 857 { 858 859 if (child->p_pptr == parent) 860 return; 861 862 if (parent == initproc) 863 child->p_exitsig = SIGCHLD; 864 865 LIST_REMOVE(child, p_sibling); 866 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 867 child->p_pptr = parent; 868 } 869