1 /* $NetBSD: kern_exit.c,v 1.300 2025/03/16 15:52:18 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 1999, 2006, 2007, 2008, 2020, 2023 5 * The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 10 * NASA Ames Research Center, and by Andrew Doran. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1982, 1986, 1989, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * All or some portions of this file are derived from material licensed 39 * to the University of California by American Telephone and Telegraph 40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 41 * the permission of UNIX System Laboratories, Inc. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)kern_exit.c 8.10 (Berkeley) 2/23/95 68 */ 69 70 #include <sys/cdefs.h> 71 __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.300 2025/03/16 15:52:18 riastradh Exp $"); 72 73 #include "opt_ktrace.h" 74 #include "opt_dtrace.h" 75 #include "opt_sysv.h" 76 77 #include <sys/param.h> 78 #include <sys/types.h> 79 80 #include <sys/acct.h> 81 #include <sys/atomic.h> 82 #include <sys/buf.h> 83 #include <sys/cpu.h> 84 #include <sys/file.h> 85 #include <sys/filedesc.h> 86 #include <sys/fstrans.h> 87 #include <sys/ioctl.h> 88 #include <sys/kauth.h> 89 #include <sys/kernel.h> 90 #include <sys/ktrace.h> 91 #include <sys/lock.h> 92 #include <sys/lockdebug.h> 93 #include <sys/lwpctl.h> 94 #include <sys/mount.h> 95 #include <sys/pool.h> 96 #include <sys/proc.h> 97 #include <sys/psref.h> 98 #include <sys/ptrace.h> 99 #include <sys/ras.h> 100 #include <sys/resource.h> 101 #include <sys/sched.h> 102 #include <sys/sdt.h> 103 #include <sys/signalvar.h> 104 #include <sys/sleepq.h> 105 #include <sys/syscallargs.h> 106 #include <sys/syslog.h> 107 #include <sys/systm.h> 108 #include <sys/time.h> 109 #include <sys/tty.h> 110 #include <sys/uidinfo.h> 111 #include <sys/vnode.h> 112 #include <sys/wait.h> 113 114 #include <uvm/uvm_extern.h> 115 116 #ifdef DEBUG_EXIT 117 int debug_exit = 0; 118 #define DPRINTF(x) if (debug_exit) printf x 119 #else 120 #define DPRINTF(x) 121 #endif 122 123 static int find_stopped_child(struct proc *, idtype_t, id_t, int, 124 struct proc **, struct wrusage *, siginfo_t *); 125 static void proc_free(struct proc *, struct wrusage *); 126 127 /* 128 * DTrace SDT provider definitions 129 */ 130 SDT_PROVIDER_DECLARE(proc); 131 SDT_PROBE_DEFINE1(proc, kernel, , exit, "int"); 132 133 /* 134 * Fill in the appropriate signal information, and signal the parent. 135 */ 136 /* XXX noclone works around a gcc 4.5 bug on arm */ 137 static void __noclone 138 exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi) 139 { 140 141 KSI_INIT(ksi); 142 if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) { 143 if (p->p_xsig) { 144 if (p->p_sflag & PS_COREDUMP) 145 ksi->ksi_code = CLD_DUMPED; 146 else 147 ksi->ksi_code = CLD_KILLED; 148 ksi->ksi_status = p->p_xsig; 149 } else { 150 ksi->ksi_code = CLD_EXITED; 151 ksi->ksi_status = p->p_xexit; 152 } 153 } else { 154 ksi->ksi_code = SI_USER; 155 ksi->ksi_status = p->p_xsig; 156 } 157 /* 158 * We fill those in, even for non-SIGCHLD. 159 * It's safe to access p->p_cred unlocked here. 160 */ 161 ksi->ksi_pid = p->p_pid; 162 ksi->ksi_uid = kauth_cred_geteuid(p->p_cred); 163 /* XXX: is this still valid? */ 164 ksi->ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; 165 ksi->ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; 166 } 167 168 /* 169 * exit -- 170 * Death of process. 171 */ 172 int 173 sys_exit(struct lwp *l, const struct sys_exit_args *uap, register_t *retval) 174 { 175 /* { 176 syscallarg(int) rval; 177 } */ 178 struct proc *p = l->l_proc; 179 180 /* Don't call exit1() multiple times in the same process. */ 181 mutex_enter(p->p_lock); 182 if (p->p_sflag & PS_WEXIT) { 183 mutex_exit(p->p_lock); 184 lwp_exit(l); 185 } 186 187 /* exit1() will release the mutex. */ 188 exit1(l, SCARG(uap, rval), 0); 189 /* NOTREACHED */ 190 return (0); 191 } 192 193 /* 194 * Exit: deallocate address space and other resources, change proc state 195 * to zombie, and unlink proc from allproc and parent's lists. Save exit 196 * status and rusage for wait(). Check for child processes and orphan them. 197 * 198 * Must be called with p->p_lock held. Does not return. 199 */ 200 void 201 exit1(struct lwp *l, int exitcode, int signo) 202 { 203 struct proc *p, *child, *next_child, *old_parent, *new_parent; 204 struct pgrp *pgrp; 205 ksiginfo_t ksi; 206 ksiginfoq_t kq; 207 int wakeinit; 208 209 p = l->l_proc; 210 211 /* Verify that we hold no locks other than p->p_lock. */ 212 LOCKDEBUG_BARRIER(p->p_lock, 0); 213 214 /* XXX Temporary: something is leaking kernel_lock. */ 215 KERNEL_UNLOCK_ALL(l, NULL); 216 217 KASSERT(mutex_owned(p->p_lock)); 218 KASSERT(p->p_vmspace != NULL); 219 220 if (__predict_false(p == initproc)) { 221 panic("init died (signal %d, exit %d)", signo, exitcode); 222 } 223 224 p->p_sflag |= PS_WEXIT; 225 226 /* 227 * Force all other LWPs to exit before we do. Only then can we 228 * begin to tear down the rest of the process state. 229 */ 230 if (p->p_nlwps > 1) { 231 exit_lwps(l); 232 } 233 234 ksiginfo_queue_init(&kq); 235 236 /* 237 * If we have been asked to stop on exit, do so now. 238 */ 239 if (__predict_false(p->p_sflag & PS_STOPEXIT)) { 240 KASSERT(l->l_blcnt == 0); 241 sigclearall(p, &contsigmask, &kq); 242 243 if (!mutex_tryenter(&proc_lock)) { 244 mutex_exit(p->p_lock); 245 mutex_enter(&proc_lock); 246 mutex_enter(p->p_lock); 247 } 248 p->p_waited = 0; 249 p->p_pptr->p_nstopchild++; 250 p->p_stat = SSTOP; 251 mutex_exit(&proc_lock); 252 lwp_lock(l); 253 p->p_nrlwps--; 254 l->l_stat = LSSTOP; 255 lwp_unlock(l); 256 mutex_exit(p->p_lock); 257 lwp_lock(l); 258 spc_lock(l->l_cpu); 259 mi_switch(l); 260 mutex_enter(p->p_lock); 261 } 262 263 /* 264 * Bin any remaining signals and mark the process as dying so it will 265 * not be found for, e.g. signals. 266 */ 267 sigfillset(&p->p_sigctx.ps_sigignore); 268 sigclearall(p, NULL, &kq); 269 p->p_stat = SDYING; 270 271 /* 272 * Perform any required thread cleanup. Do this early so 273 * anyone wanting to look us up by our global thread ID 274 * will fail to find us. 275 * 276 * N.B. this will unlock p->p_lock on our behalf. 277 */ 278 lwp_thread_cleanup(l); 279 280 ksiginfo_queue_drain(&kq); 281 282 /* Destroy any lwpctl info. */ 283 if (p->p_lwpctl != NULL) 284 lwp_ctl_exit(); 285 286 /* 287 * Drain all remaining references that procfs, ptrace and others may 288 * have on the process. 289 */ 290 rw_enter(&p->p_reflock, RW_WRITER); 291 292 DPRINTF(("%s: %d.%d exiting.\n", __func__, p->p_pid, l->l_lid)); 293 294 ptimers_free(p, TIMERS_ALL); 295 #if defined(__HAVE_RAS) 296 ras_purgeall(); 297 #endif 298 299 /* 300 * Close open files, release open-file table and free signal 301 * actions. This may block! 302 */ 303 fd_free(); 304 cwdfree(p->p_cwdi); 305 p->p_cwdi = NULL; 306 doexithooks(p); 307 sigactsfree(p->p_sigacts); 308 309 /* 310 * Write out accounting data. 311 */ 312 (void)acct_process(l); 313 314 #ifdef KTRACE 315 /* 316 * Release trace file. 317 */ 318 if (p->p_tracep != NULL) { 319 mutex_enter(&ktrace_lock); 320 ktrderef(p); 321 mutex_exit(&ktrace_lock); 322 } 323 #endif 324 325 p->p_xexit = exitcode; 326 p->p_xsig = signo; 327 328 /* 329 * If emulation has process exit hook, call it now. 330 * Set the exit status now so that the exit hook has 331 * an opportunity to tweak it (COMPAT_LINUX requires 332 * this for thread group emulation) 333 */ 334 if (p->p_emul->e_proc_exit) 335 (*p->p_emul->e_proc_exit)(p); 336 337 /* 338 * Free the VM resources we're still holding on to. 339 * We must do this from a valid thread because doing 340 * so may block. This frees vmspace, which we don't 341 * need anymore. The only remaining lwp is the one 342 * we run at this moment, nothing runs in userland 343 * anymore. 344 */ 345 ruspace(p); /* Update our vm resource use */ 346 uvm_proc_exit(p); 347 348 /* 349 * Stop profiling. 350 */ 351 if (__predict_false((p->p_stflag & PST_PROFIL) != 0)) { 352 mutex_spin_enter(&p->p_stmutex); 353 stopprofclock(p); 354 mutex_spin_exit(&p->p_stmutex); 355 } 356 357 /* 358 * If parent is waiting for us to exit or exec, PL_PPWAIT is set; we 359 * wake up the parent early to avoid deadlock. We can do this once 360 * the VM resources are released. 361 */ 362 mutex_enter(&proc_lock); 363 if (p->p_lflag & PL_PPWAIT) { 364 lwp_t *lp; 365 366 l->l_lwpctl = NULL; /* was on loan from blocked parent */ 367 p->p_lflag &= ~PL_PPWAIT; 368 369 lp = p->p_vforklwp; 370 p->p_vforklwp = NULL; 371 lp->l_vforkwaiting = false; 372 cv_broadcast(&lp->l_waitcv); 373 } 374 375 if (SESS_LEADER(p)) { 376 struct vnode *vprele = NULL, *vprevoke = NULL; 377 struct session *sp = p->p_session; 378 struct tty *tp; 379 380 if (sp->s_ttyvp) { 381 /* 382 * Controlling process. 383 * Signal foreground pgrp, 384 * drain controlling terminal 385 * and revoke access to controlling terminal. 386 */ 387 tp = sp->s_ttyp; 388 mutex_spin_enter(&tty_lock); 389 if (tp->t_session == sp) { 390 /* we can't guarantee the revoke will do this */ 391 pgrp = tp->t_pgrp; 392 tp->t_pgrp = NULL; 393 tp->t_session = NULL; 394 mutex_spin_exit(&tty_lock); 395 if (pgrp != NULL) { 396 pgsignal(pgrp, SIGHUP, 1); 397 } 398 mutex_exit(&proc_lock); 399 (void) ttywait(tp); 400 mutex_enter(&proc_lock); 401 402 /* The tty could have been revoked. */ 403 vprevoke = sp->s_ttyvp; 404 } else 405 mutex_spin_exit(&tty_lock); 406 vprele = sp->s_ttyvp; 407 sp->s_ttyvp = NULL; 408 /* 409 * s_ttyp is not zero'd; we use this to indicate 410 * that the session once had a controlling terminal. 411 * (for logging and informational purposes) 412 */ 413 } 414 sp->s_leader = NULL; 415 416 if (vprevoke != NULL || vprele != NULL) { 417 if (vprevoke != NULL) { 418 /* Releases proc_lock. */ 419 proc_sessrele(sp); 420 VOP_REVOKE(vprevoke, REVOKEALL); 421 } else 422 mutex_exit(&proc_lock); 423 if (vprele != NULL) 424 vrele(vprele); 425 mutex_enter(&proc_lock); 426 } 427 } 428 fixjobc(p, p->p_pgrp, 0); 429 430 /* Release fstrans private data. */ 431 fstrans_lwp_dtor(l); 432 433 /* 434 * Finalize the last LWP's specificdata, as well as the 435 * specificdata for the proc itself. 436 */ 437 lwp_finispecific(l); 438 proc_finispecific(p); 439 440 /* 441 * Reset p_opptr pointer of all former children which got 442 * traced by another process and were reparented. We reset 443 * it to NULL here; the trace detach code then reparents 444 * the child to initproc. We only check allproc list, since 445 * eventual former children on zombproc list won't reference 446 * p_opptr anymore. 447 */ 448 if (__predict_false(p->p_slflag & PSL_CHTRACED)) { 449 struct proc *q; 450 PROCLIST_FOREACH(q, &allproc) { 451 if (q->p_opptr == p) 452 q->p_opptr = NULL; 453 } 454 PROCLIST_FOREACH(q, &zombproc) { 455 if (q->p_opptr == p) 456 q->p_opptr = NULL; 457 } 458 } 459 460 /* 461 * Give orphaned children to init(8). 462 */ 463 child = LIST_FIRST(&p->p_children); 464 wakeinit = (child != NULL); 465 for (; child != NULL; child = next_child) { 466 next_child = LIST_NEXT(child, p_sibling); 467 468 /* 469 * Traced processes are killed since their existence 470 * means someone is screwing up. Since we reset the 471 * trace flags, the logic in sys_wait4() would not be 472 * triggered to reparent the process to its 473 * original parent, so we must do this here. 474 */ 475 if (__predict_false(child->p_slflag & PSL_TRACED)) { 476 mutex_enter(p->p_lock); 477 child->p_slflag &= 478 ~(PSL_TRACED|PSL_SYSCALL); 479 mutex_exit(p->p_lock); 480 if (child->p_opptr != child->p_pptr) { 481 struct proc *t = child->p_opptr; 482 proc_reparent(child, t ? t : initproc); 483 child->p_opptr = NULL; 484 } else 485 proc_reparent(child, initproc); 486 killproc(child, "orphaned traced process"); 487 } else 488 proc_reparent(child, initproc); 489 } 490 491 /* 492 * Move proc from allproc to zombproc, it's now nearly ready to be 493 * collected by parent. 494 */ 495 LIST_REMOVE(l, l_list); 496 LIST_REMOVE(p, p_list); 497 LIST_INSERT_HEAD(&zombproc, p, p_list); 498 499 /* 500 * Mark the process as dead. We must do this before we signal 501 * the parent. 502 */ 503 p->p_stat = SDEAD; 504 505 /* 506 * Let anyone watching this DTrace probe know what we're 507 * on our way out. 508 */ 509 SDT_PROBE(proc, kernel, , exit, 510 ((p->p_sflag & PS_COREDUMP) ? CLD_DUMPED : 511 (p->p_xsig ? CLD_KILLED : CLD_EXITED)), 512 0,0,0,0); 513 514 /* Put in front of parent's sibling list for parent to collect it */ 515 old_parent = p->p_pptr; 516 old_parent->p_nstopchild++; 517 if (LIST_FIRST(&old_parent->p_children) != p) { 518 /* Put child where it can be found quickly */ 519 LIST_REMOVE(p, p_sibling); 520 LIST_INSERT_HEAD(&old_parent->p_children, p, p_sibling); 521 } 522 523 /* 524 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 525 * flag set, notify init instead (and hope it will handle 526 * this situation). 527 */ 528 if (old_parent->p_flag & (PK_NOCLDWAIT|PK_CLDSIGIGN)) { 529 proc_reparent(p, initproc); 530 wakeinit = 1; 531 532 /* 533 * If this was the last child of our parent, notify 534 * parent, so in case he was wait(2)ing, he will 535 * continue. 536 */ 537 if (LIST_FIRST(&old_parent->p_children) == NULL) 538 cv_broadcast(&old_parent->p_waitcv); 539 } 540 541 /* Reload parent pointer, since p may have been reparented above */ 542 new_parent = p->p_pptr; 543 544 if (__predict_false(p->p_exitsig != 0)) { 545 exit_psignal(p, new_parent, &ksi); 546 kpsignal(new_parent, &ksi, NULL); 547 } 548 549 /* Calculate the final rusage info. */ 550 calcru(p, &p->p_stats->p_ru.ru_utime, &p->p_stats->p_ru.ru_stime, 551 NULL, NULL); 552 553 callout_destroy(&l->l_timeout_ch); 554 555 /* 556 * Release any PCU resources before becoming a zombie. 557 */ 558 pcu_discard_all(l); 559 560 /* 561 * Notify other processes tracking us with a knote that 562 * we're exiting. 563 * 564 * N.B. we do this here because the process is now SDEAD, 565 * and thus cannot have any more knotes attached. Also, 566 * knote_proc_exit() expects that p->p_lock is already 567 * held (and will assert so). 568 */ 569 mutex_enter(p->p_lock); 570 if (!SLIST_EMPTY(&p->p_klist)) { 571 knote_proc_exit(p); 572 } 573 574 /* Free the LWP ID */ 575 proc_free_lwpid(p, l->l_lid); 576 lwp_drainrefs(l); 577 lwp_lock(l); 578 l->l_prflag &= ~LPR_DETACHED; 579 l->l_stat = LSZOMB; 580 lwp_unlock(l); 581 KASSERT(curlwp == l); 582 KASSERT(p->p_nrlwps == 1); 583 KASSERT(p->p_nlwps == 1); 584 p->p_stat = SZOMB; 585 p->p_nrlwps--; 586 p->p_nzlwps++; 587 p->p_ndlwps = 0; 588 mutex_exit(p->p_lock); 589 590 /* 591 * Signal the parent to collect us, and drop the proclist lock. 592 * Drop debugger/procfs lock; no new references can be gained. 593 */ 594 rw_exit(&p->p_reflock); 595 cv_broadcast(&p->p_pptr->p_waitcv); 596 mutex_exit(&proc_lock); 597 if (wakeinit) 598 cv_broadcast(&initproc->p_waitcv); 599 600 /* 601 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 602 */ 603 604 /* 605 * Give machine-dependent code a chance to free any MD LWP 606 * resources. This must be done before uvm_lwp_exit(), in 607 * case these resources are in the PCB. 608 */ 609 cpu_lwp_free(l, 1); 610 611 /* Switch away into oblivion. */ 612 lwp_lock(l); 613 spc_lock(l->l_cpu); 614 mi_switch(l); 615 panic("exit1"); 616 } 617 618 void 619 exit_lwps(struct lwp *l) 620 { 621 proc_t *p = l->l_proc; 622 lwp_t *l2; 623 624 retry: 625 KASSERT(mutex_owned(p->p_lock)); 626 627 /* 628 * Interrupt LWPs in interruptable sleep, unsuspend suspended 629 * LWPs and then wait for everyone else to finish. 630 */ 631 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 632 if (l2 == l) 633 continue; 634 lwp_lock(l2); 635 l2->l_flag |= LW_WEXIT; 636 lwp_need_userret(l2); 637 if ((l2->l_stat == LSSLEEP && (l2->l_flag & LW_SINTR)) || 638 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 639 l2->l_flag &= ~LW_DBGSUSPEND; 640 /* setrunnable() will release the lock. */ 641 setrunnable(l2); 642 continue; 643 } 644 lwp_unlock(l2); 645 } 646 647 /* 648 * Wait for every LWP to exit. Note: LWPs can get suspended/slept 649 * behind us or there may even be new LWPs created. Therefore, a 650 * full retry is required on error. 651 */ 652 while (p->p_nlwps > 1) { 653 if (lwp_wait(l, 0, NULL, true)) { 654 goto retry; 655 } 656 } 657 658 KASSERT(p->p_nlwps == 1); 659 } 660 661 int 662 do_sys_waitid(idtype_t idtype, id_t id, int *pid, int *status, int options, 663 struct wrusage *wru, siginfo_t *si) 664 { 665 proc_t *child; 666 int error; 667 668 669 if (wru != NULL) 670 memset(wru, 0, sizeof(*wru)); 671 if (si != NULL) 672 memset(si, 0, sizeof(*si)); 673 674 mutex_enter(&proc_lock); 675 error = find_stopped_child(curproc, idtype, id, options, &child, 676 wru, si); 677 if (child == NULL) { 678 mutex_exit(&proc_lock); 679 *pid = 0; 680 *status = 0; 681 return error; 682 } 683 *pid = child->p_pid; 684 685 if (child->p_stat == SZOMB) { 686 /* Child is exiting */ 687 *status = P_WAITSTATUS(child); 688 /* proc_free() will release the proc_lock. */ 689 if (options & WNOWAIT) { 690 mutex_exit(&proc_lock); 691 } else { 692 proc_free(child, wru); 693 } 694 } else { 695 /* Don't mark SIGCONT if we are being stopped */ 696 *status = (child->p_xsig == SIGCONT && child->p_stat != SSTOP) ? 697 W_CONTCODE() : W_STOPCODE(child->p_xsig); 698 mutex_exit(&proc_lock); 699 } 700 return 0; 701 } 702 703 int 704 do_sys_wait(int *pid, int *status, int options, struct rusage *ru) 705 { 706 idtype_t idtype; 707 id_t id; 708 int ret; 709 struct wrusage wru; 710 711 /* 712 * Translate the special pid values into the (idtype, pid) 713 * pair for wait6. The WAIT_MYPGRP case is handled by 714 * find_stopped_child() on its own. 715 */ 716 if (*pid == WAIT_ANY) { 717 idtype = P_ALL; 718 id = 0; 719 } else if (*pid < 0) { 720 idtype = P_PGID; 721 id = (id_t)-*pid; 722 } else { 723 idtype = P_PID; 724 id = (id_t)*pid; 725 } 726 options |= WEXITED | WTRAPPED; 727 ret = do_sys_waitid(idtype, id, pid, status, options, ru ? &wru : NULL, 728 NULL); 729 if (ru) 730 *ru = wru.wru_self; 731 return ret; 732 } 733 734 int 735 sys___wait450(struct lwp *l, const struct sys___wait450_args *uap, 736 register_t *retval) 737 { 738 /* { 739 syscallarg(int) pid; 740 syscallarg(int *) status; 741 syscallarg(int) options; 742 syscallarg(struct rusage *) rusage; 743 } */ 744 int error, status, pid = SCARG(uap, pid); 745 struct rusage ru; 746 747 error = do_sys_wait(&pid, &status, SCARG(uap, options), 748 SCARG(uap, rusage) != NULL ? &ru : NULL); 749 750 retval[0] = pid; 751 if (pid == 0) { 752 return error; 753 } 754 if (SCARG(uap, status)) { 755 error = copyout(&status, SCARG(uap, status), sizeof(status)); 756 } 757 if (SCARG(uap, rusage) && error == 0) { 758 error = copyout(&ru, SCARG(uap, rusage), sizeof(ru)); 759 } 760 return error; 761 } 762 763 int 764 sys_wait6(struct lwp *l, const struct sys_wait6_args *uap, register_t *retval) 765 { 766 /* { 767 syscallarg(idtype_t) idtype; 768 syscallarg(id_t) id; 769 syscallarg(int *) status; 770 syscallarg(int) options; 771 syscallarg(struct wrusage *) wru; 772 syscallarg(siginfo_t *) si; 773 } */ 774 struct wrusage wru, *wrup; 775 siginfo_t si, *sip; 776 idtype_t idtype; 777 int pid; 778 id_t id; 779 int error, status; 780 781 idtype = SCARG(uap, idtype); 782 id = SCARG(uap, id); 783 784 if (SCARG(uap, wru) != NULL) 785 wrup = &wru; 786 else 787 wrup = NULL; 788 789 if (SCARG(uap, info) != NULL) 790 sip = &si; 791 else 792 sip = NULL; 793 794 /* 795 * We expect all callers of wait6() to know about WEXITED and 796 * WTRAPPED. 797 */ 798 error = do_sys_waitid(idtype, id, &pid, &status, SCARG(uap, options), 799 wrup, sip); 800 801 retval[0] = pid; /* tell userland who it was */ 802 803 #if 0 804 /* 805 * should we copyout if there was no process, hence no useful data? 806 * We don't for an old style wait4() (etc) but I believe 807 * FreeBSD does for wait6(), so a tossup... Go with FreeBSD for now. 808 */ 809 if (pid == 0) 810 return error; 811 #endif 812 813 if (SCARG(uap, status) != NULL && error == 0) 814 error = copyout(&status, SCARG(uap, status), sizeof(status)); 815 if (SCARG(uap, wru) != NULL && error == 0) 816 error = copyout(&wru, SCARG(uap, wru), sizeof(wru)); 817 if (SCARG(uap, info) != NULL && error == 0) 818 error = copyout(&si, SCARG(uap, info), sizeof(si)); 819 return error; 820 } 821 822 823 /* 824 * Find a process that matches the provided criteria, and fill siginfo 825 * and resources if found. 826 * Returns: 827 * -1: Not found, abort early 828 * 0: Not matched 829 * 1: Matched, there might be more matches 830 * 2: This is the only match 831 */ 832 static int 833 match_process(const struct proc *pp, struct proc **q, idtype_t idtype, id_t id, 834 int options, struct wrusage *wrusage, siginfo_t *siginfo) 835 { 836 struct rusage *rup; 837 struct proc *p = *q; 838 int rv = 1; 839 840 switch (idtype) { 841 case P_ALL: 842 mutex_enter(p->p_lock); 843 break; 844 case P_PID: 845 if (p->p_pid != (pid_t)id) { 846 p = *q = proc_find_raw((pid_t)id); 847 if (p == NULL || p->p_stat == SIDL || p->p_pptr != pp) { 848 *q = NULL; 849 return -1; 850 } 851 } 852 mutex_enter(p->p_lock); 853 rv++; 854 break; 855 case P_PGID: 856 if (p->p_pgid != (pid_t)id) 857 return 0; 858 mutex_enter(p->p_lock); 859 break; 860 case P_SID: 861 if (p->p_session->s_sid != (pid_t)id) 862 return 0; 863 mutex_enter(p->p_lock); 864 break; 865 case P_UID: 866 mutex_enter(p->p_lock); 867 if (kauth_cred_geteuid(p->p_cred) != (uid_t)id) { 868 mutex_exit(p->p_lock); 869 return 0; 870 } 871 break; 872 case P_GID: 873 mutex_enter(p->p_lock); 874 if (kauth_cred_getegid(p->p_cred) != (gid_t)id) { 875 mutex_exit(p->p_lock); 876 return 0; 877 } 878 break; 879 case P_CID: 880 case P_PSETID: 881 case P_CPUID: 882 /* XXX: Implement me */ 883 default: 884 return 0; 885 } 886 887 if ((options & WEXITED) == 0 && p->p_stat == SZOMB) { 888 mutex_exit(p->p_lock); 889 return 0; 890 } 891 892 if (siginfo != NULL) { 893 siginfo->si_errno = 0; 894 895 /* 896 * SUSv4 requires that the si_signo value is always 897 * SIGCHLD. Obey it despite the rfork(2) interface 898 * allows to request other signal for child exit 899 * notification. 900 */ 901 siginfo->si_signo = SIGCHLD; 902 903 /* 904 * This is still a rough estimate. We will fix the 905 * cases TRAPPED, STOPPED, and CONTINUED later. 906 */ 907 if (p->p_sflag & PS_COREDUMP) { 908 siginfo->si_code = CLD_DUMPED; 909 siginfo->si_status = p->p_xsig; 910 } else if (p->p_xsig) { 911 siginfo->si_code = CLD_KILLED; 912 siginfo->si_status = p->p_xsig; 913 } else { 914 siginfo->si_code = CLD_EXITED; 915 siginfo->si_status = p->p_xexit; 916 } 917 918 siginfo->si_pid = p->p_pid; 919 siginfo->si_uid = kauth_cred_geteuid(p->p_cred); 920 siginfo->si_utime = p->p_stats->p_ru.ru_utime.tv_sec; 921 siginfo->si_stime = p->p_stats->p_ru.ru_stime.tv_sec; 922 } 923 924 /* 925 * There should be no reason to limit resources usage info to 926 * exited processes only. A snapshot about any resources used 927 * by a stopped process may be exactly what is needed. 928 */ 929 if (wrusage != NULL) { 930 rup = &wrusage->wru_self; 931 *rup = p->p_stats->p_ru; 932 calcru(p, &rup->ru_utime, &rup->ru_stime, NULL, NULL); 933 934 rup = &wrusage->wru_children; 935 *rup = p->p_stats->p_cru; 936 calcru(p, &rup->ru_utime, &rup->ru_stime, NULL, NULL); 937 } 938 939 mutex_exit(p->p_lock); 940 return rv; 941 } 942 943 /* 944 * Determine if there are existing processes being debugged 945 * that used to be (and sometime later will be again) children 946 * of a specific parent (while matching wait criteria) 947 */ 948 static bool 949 debugged_child_exists(idtype_t idtype, id_t id, int options, siginfo_t *si, 950 const struct proc *parent) 951 { 952 struct proc *pp; 953 954 /* 955 * If we are searching for a specific pid, we can optimise a little 956 */ 957 if (idtype == P_PID) { 958 /* 959 * Check the specific process to see if its real parent is us 960 */ 961 pp = proc_find_raw((pid_t)id); 962 if (pp != NULL && pp->p_stat != SIDL && pp->p_opptr == parent) { 963 /* 964 * using P_ALL here avoids match_process() doing the 965 * same work that we just did, but incorrectly for 966 * this scenario. 967 */ 968 if (match_process(parent, &pp, P_ALL, id, options, 969 NULL, si)) 970 return true; 971 } 972 return false; 973 } 974 975 /* 976 * For the hard cases, just look everywhere to see if some 977 * stolen (reparented) process is really our lost child. 978 * Then check if that process could satisfy the wait conditions. 979 */ 980 981 /* 982 * XXX inefficient, but hopefully fairly rare. 983 * XXX should really use a list of reparented processes. 984 */ 985 PROCLIST_FOREACH(pp, &allproc) { 986 if (pp->p_stat == SIDL) /* XXX impossible ?? */ 987 continue; 988 if (pp->p_opptr == parent && 989 match_process(parent, &pp, idtype, id, options, NULL, si)) 990 return true; 991 } 992 PROCLIST_FOREACH(pp, &zombproc) { 993 if (pp->p_stat == SIDL) /* XXX impossible ?? */ 994 continue; 995 if (pp->p_opptr == parent && 996 match_process(parent, &pp, idtype, id, options, NULL, si)) 997 return true; 998 } 999 1000 return false; 1001 } 1002 1003 /* 1004 * Scan list of child processes for a child process that has stopped or 1005 * exited. Used by sys_wait4 and 'compat' equivalents. 1006 * 1007 * Must be called with the proc_lock held, and may release while waiting. 1008 */ 1009 static int 1010 find_stopped_child(struct proc *parent, idtype_t idtype, id_t id, int options, 1011 struct proc **child_p, struct wrusage *wru, siginfo_t *si) 1012 { 1013 struct proc *child, *dead; 1014 int error; 1015 1016 KASSERT(mutex_owned(&proc_lock)); 1017 1018 if (options & ~WALLOPTS) { 1019 *child_p = NULL; 1020 return SET_ERROR(EINVAL); 1021 } 1022 1023 if ((options & WSELECTOPTS) == 0) { 1024 /* 1025 * We will be unable to find any matching processes, 1026 * because there are no known events to look for. 1027 * Prefer to return error instead of blocking 1028 * indefinitely. 1029 */ 1030 *child_p = NULL; 1031 return SET_ERROR(EINVAL); 1032 } 1033 1034 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { 1035 id = (id_t)parent->p_pgid; 1036 idtype = P_PGID; 1037 } 1038 1039 for (;;) { 1040 error = ECHILD; 1041 dead = NULL; 1042 1043 LIST_FOREACH(child, &parent->p_children, p_sibling) { 1044 int rv = match_process(parent, &child, idtype, id, 1045 options, wru, si); 1046 if (rv == -1) 1047 break; 1048 if (rv == 0) 1049 continue; 1050 1051 /* 1052 * Wait for processes with p_exitsig != SIGCHLD 1053 * processes only if WALTSIG is set; wait for 1054 * processes with p_exitsig == SIGCHLD only 1055 * if WALTSIG is clear. 1056 */ 1057 if (((options & WALLSIG) == 0) && 1058 (options & WALTSIG ? child->p_exitsig == SIGCHLD 1059 : P_EXITSIG(child) != SIGCHLD)){ 1060 if (rv == 2) { 1061 child = NULL; 1062 break; 1063 } 1064 continue; 1065 } 1066 1067 error = 0; 1068 if ((options & WNOZOMBIE) == 0) { 1069 if (child->p_stat == SZOMB) 1070 break; 1071 if (child->p_stat == SDEAD) { 1072 /* 1073 * We may occasionally arrive here 1074 * after receiving a signal, but 1075 * immediately before the child 1076 * process is zombified. The wait 1077 * will be short, so avoid returning 1078 * to userspace. 1079 */ 1080 dead = child; 1081 } 1082 } 1083 1084 if ((options & WCONTINUED) != 0 && 1085 child->p_xsig == SIGCONT && 1086 (child->p_sflag & PS_CONTINUED)) { 1087 if ((options & WNOWAIT) == 0) { 1088 child->p_sflag &= ~PS_CONTINUED; 1089 child->p_waited = 1; 1090 parent->p_nstopchild--; 1091 } 1092 if (si) { 1093 si->si_status = child->p_xsig; 1094 si->si_code = CLD_CONTINUED; 1095 } 1096 break; 1097 } 1098 1099 if ((options & (WTRAPPED|WSTOPPED)) != 0 && 1100 child->p_stat == SSTOP && 1101 child->p_waited == 0 && 1102 ((child->p_slflag & PSL_TRACED) || 1103 options & (WUNTRACED|WSTOPPED))) { 1104 if ((options & WNOWAIT) == 0) { 1105 child->p_waited = 1; 1106 parent->p_nstopchild--; 1107 } 1108 if (si) { 1109 si->si_status = child->p_xsig; 1110 si->si_code = 1111 (child->p_slflag & PSL_TRACED) ? 1112 CLD_TRAPPED : CLD_STOPPED; 1113 } 1114 break; 1115 } 1116 if (parent->p_nstopchild == 0 || rv == 2) { 1117 child = NULL; 1118 break; 1119 } 1120 } 1121 1122 /* 1123 * If we found nothing, but we are the bereaved parent 1124 * of a stolen child, look and see if that child (or 1125 * one of them) meets our search criteria. If so, then 1126 * we cannot succeed, but we can hang (wait...), 1127 * or if WNOHANG, return 0 instead of ECHILD 1128 */ 1129 if (child == NULL && error == ECHILD && 1130 (parent->p_slflag & PSL_CHTRACED) && 1131 debugged_child_exists(idtype, id, options, si, parent)) 1132 error = 0; 1133 1134 if (child != NULL || error != 0 || 1135 ((options & WNOHANG) != 0 && dead == NULL)) { 1136 *child_p = child; 1137 return SET_ERROR(error); 1138 } 1139 1140 /* 1141 * Wait for another child process to stop. 1142 */ 1143 error = cv_wait_sig(&parent->p_waitcv, &proc_lock); 1144 1145 if (error != 0) { 1146 *child_p = NULL; 1147 return error; 1148 } 1149 } 1150 } 1151 1152 /* 1153 * Free a process after parent has taken all the state info. Must be called 1154 * with the proclist lock held, and will release before returning. 1155 * 1156 * *ru is returned to the caller, and must be freed by the caller. 1157 */ 1158 static void 1159 proc_free(struct proc *p, struct wrusage *wru) 1160 { 1161 struct proc *parent = p->p_pptr; 1162 struct lwp *l; 1163 ksiginfo_t ksi; 1164 kauth_cred_t cred1, cred2; 1165 uid_t uid; 1166 1167 KASSERT(mutex_owned(&proc_lock)); 1168 KASSERT(p->p_nlwps == 1); 1169 KASSERT(p->p_nzlwps == 1); 1170 KASSERT(p->p_nrlwps == 0); 1171 KASSERT(p->p_stat == SZOMB); 1172 1173 /* 1174 * If we got the child via ptrace(2) or procfs, and 1175 * the parent is different (meaning the process was 1176 * attached, rather than run as a child), then we need 1177 * to give it back to the old parent, and send the 1178 * parent the exit signal. The rest of the cleanup 1179 * will be done when the old parent waits on the child. 1180 */ 1181 if ((p->p_slflag & PSL_TRACED) != 0 && p->p_opptr != parent) { 1182 mutex_enter(p->p_lock); 1183 p->p_slflag &= ~(PSL_TRACED|PSL_SYSCALL); 1184 mutex_exit(p->p_lock); 1185 parent = (p->p_opptr == NULL) ? initproc : p->p_opptr; 1186 proc_reparent(p, parent); 1187 p->p_opptr = NULL; 1188 if (p->p_exitsig != 0) { 1189 exit_psignal(p, parent, &ksi); 1190 kpsignal(parent, &ksi, NULL); 1191 } 1192 cv_broadcast(&parent->p_waitcv); 1193 mutex_exit(&proc_lock); 1194 return; 1195 } 1196 1197 sched_proc_exit(parent, p); 1198 1199 /* 1200 * Add child times of exiting process onto its own times. 1201 * This cannot be done any earlier else it might get done twice. 1202 */ 1203 l = LIST_FIRST(&p->p_lwps); 1204 ruadd(&p->p_stats->p_ru, &l->l_ru); 1205 ruadd(&p->p_stats->p_ru, &p->p_stats->p_cru); 1206 ruadd(&parent->p_stats->p_cru, &p->p_stats->p_ru); 1207 if (wru != NULL) { 1208 wru->wru_self = p->p_stats->p_ru; 1209 wru->wru_children = p->p_stats->p_cru; 1210 } 1211 p->p_xsig = 0; 1212 p->p_xexit = 0; 1213 1214 /* 1215 * At this point we are going to start freeing the final resources. 1216 * If anyone tries to access the proc structure after here they will 1217 * get a shock - bits are missing. Attempt to make it hard! We 1218 * don't bother with any further locking past this point. 1219 */ 1220 p->p_stat = SIDL; /* not even a zombie any more */ 1221 LIST_REMOVE(p, p_list); /* off zombproc */ 1222 parent->p_nstopchild--; 1223 LIST_REMOVE(p, p_sibling); 1224 1225 /* 1226 * Let pid be reallocated. 1227 */ 1228 proc_free_pid(p->p_pid); 1229 atomic_dec_uint(&nprocs); 1230 1231 /* 1232 * Unlink process from its process group. 1233 * Releases the proc_lock. 1234 */ 1235 proc_leavepgrp(p); 1236 1237 /* 1238 * Delay release until after lwp_free. 1239 */ 1240 cred2 = l->l_cred; 1241 1242 /* 1243 * Free the last LWP's resources. 1244 * 1245 * lwp_free ensures the LWP is no longer running on another CPU. 1246 */ 1247 lwp_free(l, false, true); 1248 1249 /* 1250 * Now no one except us can reach the process p. 1251 */ 1252 1253 /* 1254 * Decrement the count of procs running with this uid. 1255 */ 1256 cred1 = p->p_cred; 1257 uid = kauth_cred_getuid(cred1); 1258 (void)chgproccnt(uid, -1); 1259 1260 /* 1261 * Release substructures. 1262 */ 1263 1264 lim_free(p->p_limit); 1265 pstatsfree(p->p_stats); 1266 kauth_cred_free(cred1); 1267 kauth_cred_free(cred2); 1268 1269 /* 1270 * Release reference to text vnode 1271 */ 1272 if (p->p_textvp) 1273 vrele(p->p_textvp); 1274 kmem_strfree(p->p_path); 1275 1276 mutex_destroy(&p->p_auxlock); 1277 mutex_obj_free(p->p_lock); 1278 mutex_destroy(&p->p_stmutex); 1279 cv_destroy(&p->p_waitcv); 1280 cv_destroy(&p->p_lwpcv); 1281 rw_destroy(&p->p_reflock); 1282 1283 proc_free_mem(p); 1284 } 1285 1286 /* 1287 * Change the parent of a process for tracing purposes. 1288 */ 1289 void 1290 proc_changeparent(struct proc *t, struct proc *p) 1291 { 1292 SET(t->p_slflag, PSL_TRACED); 1293 t->p_opptr = t->p_pptr; 1294 if (t->p_pptr == p) 1295 return; 1296 struct proc *parent = t->p_pptr; 1297 1298 if (parent->p_lock < t->p_lock) { 1299 if (!mutex_tryenter(parent->p_lock)) { 1300 mutex_exit(t->p_lock); 1301 mutex_enter(parent->p_lock); 1302 mutex_enter(t->p_lock); 1303 } 1304 } else if (parent->p_lock > t->p_lock) { 1305 mutex_enter(parent->p_lock); 1306 } 1307 parent->p_slflag |= PSL_CHTRACED; 1308 proc_reparent(t, p); 1309 if (parent->p_lock != t->p_lock) 1310 mutex_exit(parent->p_lock); 1311 } 1312 1313 /* 1314 * make process 'parent' the new parent of process 'child'. 1315 * 1316 * Must be called with proc_lock held. 1317 */ 1318 void 1319 proc_reparent(struct proc *child, struct proc *parent) 1320 { 1321 1322 KASSERT(mutex_owned(&proc_lock)); 1323 1324 if (child->p_pptr == parent) 1325 return; 1326 1327 if (child->p_stat == SZOMB || child->p_stat == SDEAD || 1328 (child->p_stat == SSTOP && !child->p_waited)) { 1329 child->p_pptr->p_nstopchild--; 1330 parent->p_nstopchild++; 1331 } 1332 if (parent == initproc) { 1333 child->p_exitsig = SIGCHLD; 1334 child->p_ppid = parent->p_pid; 1335 } 1336 1337 LIST_REMOVE(child, p_sibling); 1338 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1339 child->p_pptr = parent; 1340 } 1341