1 /* $NetBSD: kern_exit.c,v 1.135 2004/02/09 13:11:21 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 1.135 2004/02/09 13:11:21 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 static void exit_psignal(struct proc *, struct proc *); 132 133 /* 134 * Fill in the appropriate signal information, and signal 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 if (p->p_flag & P_STOPEXIT) { 203 int s; 204 205 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); 267 268 doexithooks(p); 269 270 if (SESS_LEADER(p)) { 271 struct session *sp = p->p_session; 272 struct tty *tp; 273 274 if (sp->s_ttyvp) { 275 /* 276 * Controlling process. 277 * Signal foreground pgrp, 278 * drain controlling terminal 279 * and revoke access to controlling terminal. 280 */ 281 tp = sp->s_ttyp; 282 TTY_LOCK(tp); 283 if (tp->t_session == sp) { 284 if (tp->t_pgrp) 285 pgsignal(tp->t_pgrp, SIGHUP, 1); 286 /* we can't guarantee the revoke will do this */ 287 tp->t_pgrp = NULL; 288 tp->t_session = NULL; 289 TTY_UNLOCK(tp); 290 SESSRELE(sp); 291 (void) ttywait(tp); 292 /* 293 * The tty could have been revoked 294 * if we blocked. 295 */ 296 if (sp->s_ttyvp) 297 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 298 } else 299 TTY_UNLOCK(tp); 300 if (sp->s_ttyvp) 301 vrele(sp->s_ttyvp); 302 sp->s_ttyvp = NULL; 303 /* 304 * s_ttyp is not zero'd; we use this to indicate 305 * that the session once had a controlling terminal. 306 * (for logging and informational purposes) 307 */ 308 } 309 sp->s_leader = NULL; 310 } 311 fixjobc(p, p->p_pgrp, 0); 312 (void)acct_process(p); 313 #ifdef KTRACE 314 /* 315 * release trace file 316 */ 317 ktrderef(p); 318 #endif 319 #ifdef SYSTRACE 320 systrace_sys_exit(p); 321 #endif 322 /* 323 * If emulation has process exit hook, call it now. 324 */ 325 if (p->p_emul->e_proc_exit) 326 (*p->p_emul->e_proc_exit)(p); 327 328 /* 329 * Reset p_opptr pointer of all former children which got 330 * traced by another process and were reparented. We reset 331 * it to NULL here; the trace detach code then reparents 332 * the child to initproc. We only check allproc list, since 333 * eventual former children on zombproc list won't reference 334 * p_opptr anymore. 335 */ 336 s = proclist_lock_write(); 337 if (p->p_flag & P_CHTRACED) { 338 LIST_FOREACH(q, &allproc, p_list) { 339 if (q->p_opptr == p) 340 q->p_opptr = NULL; 341 } 342 } 343 344 /* 345 * Give orphaned children to init(8). 346 */ 347 q = LIST_FIRST(&p->p_children); 348 if (q) /* only need this if any child is SZOMB */ 349 wakeup(initproc); 350 for (; q != NULL; q = nq) { 351 nq = LIST_NEXT(q, p_sibling); 352 353 /* 354 * Traced processes are killed since their existence 355 * means someone is screwing up. Since we reset the 356 * trace flags, the logic in sys_wait4() would not be 357 * triggered to reparent the process to its 358 * original parent, so we must do this here. 359 */ 360 if (q->p_flag & P_TRACED) { 361 if (q->p_opptr != q->p_pptr) { 362 struct proc *t = q->p_opptr; 363 proc_reparent(q, t ? t : initproc); 364 q->p_opptr = NULL; 365 } else 366 proc_reparent(q, initproc); 367 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 368 psignal(q, SIGKILL); 369 } else { 370 proc_reparent(q, initproc); 371 } 372 } 373 proclist_unlock_write(s); 374 375 /* 376 * Free the VM resources we're still holding on to. 377 * We must do this from a valid thread because doing 378 * so may block. This frees vmspace, which we don't 379 * need anymore. The only remaining lwp is the one 380 * we run at this moment, nothing runs in userland 381 * anymore. 382 */ 383 uvm_proc_exit(p); 384 385 /* 386 * Give machine-dependent code a chance to free any 387 * MD LWP resources while we can still block. This must be done 388 * before uvm_lwp_exit(), in case these resources are in the 389 * PCB. 390 * THIS IS LAST BLOCKING OPERATION. 391 */ 392 #ifndef __NO_CPU_LWP_FREE 393 cpu_lwp_free(l, 1); 394 #endif 395 396 /* 397 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 398 */ 399 400 /* 401 * Save exit status and final rusage info, adding in child rusage 402 * info and self times. 403 * In order to pick up the time for the current execution, we must 404 * do this before unlinking the lwp from l_list. 405 */ 406 p->p_xstat = rv; 407 *p->p_ru = p->p_stats->p_ru; 408 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 409 ruadd(p->p_ru, &p->p_stats->p_cru); 410 411 /* 412 * Move proc from allproc to zombproc, it's now ready 413 * to be collected by parent. Remaining lwp resources 414 * will be freed in lwp_exit2() once we'd switch to idle 415 * context. 416 * Changing the state to SZOMB stops it being found by pfind(). 417 */ 418 s = proclist_lock_write(); 419 LIST_REMOVE(p, p_list); 420 LIST_INSERT_HEAD(&zombproc, p, p_list); 421 p->p_stat = SZOMB; 422 423 LIST_REMOVE(l, l_list); 424 l->l_flag |= L_DETACHED|L_PROCEXIT; /* detached from proc too */ 425 l->l_stat = LSDEAD; 426 427 p->p_nrlwps--; 428 p->p_nlwps--; 429 430 /* Put in front of parent's sibling list for parent to collect it */ 431 q = p->p_pptr; 432 q->p_nstopchild++; 433 if (LIST_FIRST(&q->p_children) != p) { 434 /* Put child where it can be found quickly */ 435 LIST_REMOVE(p, p_sibling); 436 LIST_INSERT_HEAD(&q->p_children, p, p_sibling); 437 } 438 439 proclist_unlock_write(s); 440 441 /* 442 * Notify interested parties of our demise. 443 */ 444 KNOTE(&p->p_klist, NOTE_EXIT); 445 446 #if PERFCTRS 447 /* 448 * Save final PMC information in parent process & clean up. 449 */ 450 if (PMC_ENABLED(p)) { 451 pmc_save_context(p); 452 pmc_accumulate(p->p_pptr, p); 453 pmc_process_exit(p); 454 } 455 #endif 456 457 /* 458 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 459 * flag set, notify init instead (and hope it will handle 460 * this situation). 461 */ 462 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 463 struct proc *pp = p->p_pptr; 464 proc_reparent(p, initproc); 465 466 /* 467 * If this was the last child of our parent, notify 468 * parent, so in case he was wait(2)ing, he will 469 * continue. 470 */ 471 if (LIST_FIRST(&pp->p_children) == NULL) 472 wakeup(pp); 473 } 474 475 /* Wake up the parent so it can get exit status. */ 476 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 477 exit_psignal(p, p->p_pptr); 478 wakeup(p->p_pptr); 479 480 /* 481 * Release the process's signal state. 482 */ 483 sigactsfree(p); 484 485 /* 486 * Clear curlwp after we've done all operations 487 * that could block, and before tearing down the rest 488 * of the process state that might be used from clock, etc. 489 * Also, can't clear curlwp while we're still runnable, 490 * as we're not on a run queue (we are current, just not 491 * a proper proc any longer!). 492 * 493 * Other substructures are freed from wait(). 494 */ 495 curlwp = NULL; 496 limfree(p->p_limit); 497 pstatsfree(p->p_stats); 498 p->p_limit = NULL; 499 500 /* This process no longer needs to hold the kernel lock. */ 501 KERNEL_PROC_UNLOCK(l); 502 503 pmap_deactivate(l); 504 505 #ifdef DEBUG 506 /* Nothing should use the process link anymore */ 507 l->l_proc = NULL; 508 #endif 509 510 /* 511 * Finally, call machine-dependent code to switch to a new 512 * context (possibly the idle context). Once we are no longer 513 * using the dead lwp's stack, lwp_exit2() will be called 514 * to arrange for the resources to be released. 515 * 516 * Note that cpu_exit() will end with a call equivalent to 517 * cpu_switch(), finishing our execution (pun intended). 518 */ 519 520 uvmexp.swtch++; 521 cpu_exit(l); 522 } 523 524 void 525 exit_lwps(struct lwp *l) 526 { 527 struct proc *p; 528 struct lwp *l2; 529 int s, error; 530 lwpid_t waited; 531 532 p = l->l_proc; 533 534 /* XXX SMP 535 * This would be the right place to IPI any LWPs running on 536 * other processors so that they can notice the userret exit hook. 537 */ 538 p->p_userret = lwp_exit_hook; 539 p->p_userret_arg = NULL; 540 541 if (p->p_sa) { 542 /* 543 * Make SA-cached LWPs normal process runnable LWPs so 544 * that they'll also self-destruct. 545 */ 546 DPRINTF(("exit_lwps: Making cached LWPs of %d runnable: ", 547 p->p_pid)); 548 SCHED_LOCK(s); 549 while ((l2 = sa_getcachelwp(p)) != 0) { 550 l2->l_priority = l2->l_usrpri; 551 setrunnable(l2); 552 DPRINTF(("%d ", l2->l_lid)); 553 } 554 DPRINTF(("\n")); 555 SCHED_UNLOCK(s); 556 557 /* Clear wokenq, the LWPs on the queue will run below */ 558 p->p_sa->sa_wokenq_head = NULL; 559 } 560 561 /* 562 * Interrupt LWPs in interruptable sleep, unsuspend suspended 563 * LWPs, make detached LWPs undetached (so we can wait for 564 * them) and then wait for everyone else to finish. 565 */ 566 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 567 l2->l_flag &= ~(L_DETACHED|L_SA); 568 569 if (p->p_sa && l2->l_wchan == p->p_sa) 570 l2->l_flag |= L_SINTR; 571 572 if ((l2->l_stat == LSSLEEP && (l2->l_flag & L_SINTR)) || 573 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 574 SCHED_LOCK(s); 575 setrunnable(l2); 576 SCHED_UNLOCK(s); 577 DPRINTF(("exit_lwps: Made %d.%d runnable\n", 578 p->p_pid, l2->l_lid)); 579 } 580 } 581 582 583 while (p->p_nlwps > 1) { 584 DPRINTF(("exit_lwps: waiting for %d LWPs (%d runnable, %d zombies)\n", 585 p->p_nlwps, p->p_nrlwps, p->p_nzlwps)); 586 error = lwp_wait1(l, 0, &waited, LWPWAIT_EXITCONTROL); 587 if (error) 588 panic("exit_lwps: lwp_wait1 failed with error %d\n", 589 error); 590 DPRINTF(("exit_lwps: Got LWP %d from lwp_wait1()\n", waited)); 591 } 592 593 p->p_userret = NULL; 594 } 595 596 /* Wrapper function for use in p_userret */ 597 static void 598 lwp_exit_hook(struct lwp *l, void *arg) 599 { 600 KERNEL_PROC_LOCK(l); 601 lwp_exit(l); 602 } 603 604 int 605 sys_wait4(struct lwp *l, void *v, register_t *retval) 606 { 607 struct sys_wait4_args /* { 608 syscallarg(int) pid; 609 syscallarg(int *) status; 610 syscallarg(int) options; 611 syscallarg(struct rusage *) rusage; 612 } */ *uap = v; 613 struct proc *child, *parent; 614 int status, error; 615 616 parent = l->l_proc; 617 618 if (SCARG(uap, pid) == 0) 619 SCARG(uap, pid) = -parent->p_pgid; 620 if (SCARG(uap, options) & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG)) 621 return (EINVAL); 622 623 error = find_stopped_child(parent, SCARG(uap,pid), SCARG(uap,options), 624 &child); 625 if (error != 0) 626 return error; 627 if (child == NULL) { 628 *retval = 0; 629 return 0; 630 } 631 632 /* 633 * Collect child u-areas. 634 */ 635 uvm_uarea_drain(FALSE); 636 637 retval[0] = child->p_pid; 638 639 if (child->p_stat == SZOMB) { 640 if (SCARG(uap, status)) { 641 status = child->p_xstat; /* convert to int */ 642 error = copyout(&status, SCARG(uap, status), 643 sizeof(status)); 644 if (error) 645 return (error); 646 } 647 if (SCARG(uap, rusage)) { 648 error = copyout(child->p_ru, SCARG(uap, rusage), 649 sizeof(struct rusage)); 650 if (error) 651 return (error); 652 } 653 654 proc_free(child); 655 return 0; 656 } 657 658 /* child state must be SSTOP */ 659 if (SCARG(uap, status)) { 660 status = W_STOPCODE(child->p_xstat); 661 return copyout(&status, SCARG(uap, status), sizeof(status)); 662 } 663 return 0; 664 } 665 666 /* 667 * Scan list of child processes for a child process that has stopped or 668 * exited. Used by sys_wait4 and 'compat' equivalents. 669 */ 670 int 671 find_stopped_child(struct proc *parent, pid_t pid, int options, 672 struct proc **child_p) 673 { 674 struct proc *child; 675 int error; 676 677 for (;;) { 678 proclist_lock_read(); 679 error = ECHILD; 680 LIST_FOREACH(child, &parent->p_children, p_sibling) { 681 if (pid >= 0) { 682 if (child->p_pid != pid) { 683 child = p_find(pid, PFIND_ZOMBIE | 684 PFIND_LOCKED); 685 if (child == NULL 686 || child->p_pptr != parent) { 687 child = NULL; 688 break; 689 } 690 } 691 } else 692 if (pid != WAIT_ANY && child->p_pgid != -pid) 693 /* child not in correct pgrp */ 694 continue; 695 /* 696 * Wait for processes with p_exitsig != SIGCHLD 697 * processes only if WALTSIG is set; wait for 698 * processes with p_exitsig == SIGCHLD only 699 * if WALTSIG is clear. 700 */ 701 if (((options & WALLSIG) == 0) && 702 (options & WALTSIG ? child->p_exitsig == SIGCHLD 703 : P_EXITSIG(child) != SIGCHLD)){ 704 if (child->p_pid == pid) { 705 child = NULL; 706 break; 707 } 708 continue; 709 } 710 711 error = 0; 712 if (child->p_stat == SZOMB && !(options & WNOZOMBIE)) 713 break; 714 715 if (child->p_stat == SSTOP && 716 (child->p_flag & P_WAITED) == 0 && 717 (child->p_flag & P_TRACED || options & WUNTRACED)) { 718 if ((options & WNOWAIT) == 0) { 719 child->p_flag |= P_WAITED; 720 parent->p_nstopchild--; 721 } 722 break; 723 } 724 if (parent->p_nstopchild == 0 || child->p_pid == pid) { 725 child = NULL; 726 break; 727 } 728 } 729 proclist_unlock_read(); 730 if (child != NULL || error != 0 || options & WNOHANG) { 731 *child_p = child; 732 return error; 733 } 734 error = tsleep(parent, PWAIT | PCATCH, "wait", 0); 735 if (error != 0) 736 return error; 737 } 738 } 739 740 /* 741 * Free a process after parent has taken all the state info. 742 */ 743 void 744 proc_free(struct proc *p) 745 { 746 struct proc *parent = p->p_pptr; 747 int s; 748 749 /* 750 * If we got the child via ptrace(2) or procfs, and 751 * the parent is different (meaning the process was 752 * attached, rather than run as a child), then we need 753 * to give it back to the old parent, and send the 754 * parent the exit signal. The rest of the cleanup 755 * will be done when the old parent waits on the child. 756 */ 757 if ((p->p_flag & P_TRACED) && p->p_opptr != parent){ 758 parent = p->p_opptr; 759 if (parent == NULL) 760 parent = initproc; 761 proc_reparent(p, parent); 762 p->p_opptr = NULL; 763 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 764 if (p->p_exitsig != 0) 765 exit_psignal(p, parent); 766 wakeup(parent); 767 return; 768 } 769 770 scheduler_wait_hook(parent, p); 771 p->p_xstat = 0; 772 773 ruadd(&parent->p_stats->p_cru, p->p_ru); 774 775 /* 776 * At this point we are going to start freeing the final resources. 777 * If anyone tries to access the proc structure after here they 778 * will get a shock - bits are missing. 779 * Attempt to make it hard! 780 */ 781 782 p->p_stat = SIDL; /* not even a zombie any more */ 783 784 pool_put(&rusage_pool, p->p_ru); 785 786 /* 787 * Finally finished with old proc entry. 788 * Unlink it from its process group and free it. 789 */ 790 leavepgrp(p); 791 792 s = proclist_lock_write(); 793 LIST_REMOVE(p, p_list); /* off zombproc */ 794 p->p_pptr->p_nstopchild--; 795 LIST_REMOVE(p, p_sibling); 796 proclist_unlock_write(s); 797 798 /* 799 * Decrement the count of procs running with this uid. 800 */ 801 (void)chgproccnt(p->p_cred->p_ruid, -1); 802 803 /* 804 * Free up credentials. 805 */ 806 if (--p->p_cred->p_refcnt == 0) { 807 crfree(p->p_cred->pc_ucred); 808 pool_put(&pcred_pool, p->p_cred); 809 } 810 811 /* 812 * Release reference to text vnode 813 */ 814 if (p->p_textvp) 815 vrele(p->p_textvp); 816 817 /* Release any SA state. */ 818 if (p->p_sa) 819 sa_release(p); 820 821 /* Free proc structure and let pid be reallocated */ 822 proc_free_mem(p); 823 } 824 825 /* 826 * make process 'parent' the new parent of process 'child'. 827 * 828 * Must be called with proclist_lock_write() held. 829 */ 830 void 831 proc_reparent(struct proc *child, struct proc *parent) 832 { 833 834 if (child->p_pptr == parent) 835 return; 836 837 if (child->p_stat == SZOMB 838 || (child->p_stat == SSTOP && !(child->p_flag & P_WAITED))) { 839 child->p_pptr->p_nstopchild--; 840 parent->p_nstopchild++; 841 } 842 if (parent == initproc) 843 child->p_exitsig = SIGCHLD; 844 845 LIST_REMOVE(child, p_sibling); 846 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 847 child->p_pptr = parent; 848 } 849