1 /* $NetBSD: kern_exit.c,v 1.258 2016/04/27 21:15:40 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 1999, 2006, 2007, 2008 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, and by Andrew Doran. 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 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1982, 1986, 1989, 1991, 1993 35 * The Regents of the University of California. All rights reserved. 36 * (c) UNIX System Laboratories, Inc. 37 * All or some portions of this file are derived from material licensed 38 * to the University of California by American Telephone and Telegraph 39 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 40 * the permission of UNIX System Laboratories, Inc. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)kern_exit.c 8.10 (Berkeley) 2/23/95 67 */ 68 69 #include <sys/cdefs.h> 70 __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.258 2016/04/27 21:15:40 christos Exp $"); 71 72 #include "opt_ktrace.h" 73 #include "opt_dtrace.h" 74 #include "opt_perfctrs.h" 75 #include "opt_sysv.h" 76 77 #include <sys/param.h> 78 #include <sys/systm.h> 79 #include <sys/ioctl.h> 80 #include <sys/tty.h> 81 #include <sys/time.h> 82 #include <sys/resource.h> 83 #include <sys/kernel.h> 84 #include <sys/proc.h> 85 #include <sys/buf.h> 86 #include <sys/wait.h> 87 #include <sys/file.h> 88 #include <sys/vnode.h> 89 #include <sys/syslog.h> 90 #include <sys/pool.h> 91 #include <sys/uidinfo.h> 92 #if defined(PERFCTRS) 93 #include <sys/pmc.h> 94 #endif 95 #include <sys/ptrace.h> 96 #include <sys/acct.h> 97 #include <sys/filedesc.h> 98 #include <sys/ras.h> 99 #include <sys/signalvar.h> 100 #include <sys/sched.h> 101 #include <sys/mount.h> 102 #include <sys/syscallargs.h> 103 #include <sys/kauth.h> 104 #include <sys/sleepq.h> 105 #include <sys/lockdebug.h> 106 #include <sys/ktrace.h> 107 #include <sys/cpu.h> 108 #include <sys/lwpctl.h> 109 #include <sys/atomic.h> 110 #include <sys/sdt.h> 111 112 #include <uvm/uvm_extern.h> 113 114 #ifdef DEBUG_EXIT 115 int debug_exit = 0; 116 #define DPRINTF(x) if (debug_exit) printf x 117 #else 118 #define DPRINTF(x) 119 #endif 120 121 static int find_stopped_child(struct proc *, idtype_t, id_t, int, 122 struct proc **, struct wrusage *, siginfo_t *); 123 static void proc_free(struct proc *, struct wrusage *); 124 125 /* 126 * DTrace SDT provider definitions 127 */ 128 SDT_PROVIDER_DECLARE(proc); 129 SDT_PROBE_DEFINE1(proc, kernel, , exit, "int"); 130 131 /* 132 * Fill in the appropriate signal information, and signal the parent. 133 */ 134 /* XXX noclone works around a gcc 4.5 bug on arm */ 135 static void __noclone 136 exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi) 137 { 138 139 KSI_INIT(ksi); 140 if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) { 141 if (p->p_xsig) { 142 if (p->p_sflag & PS_COREDUMP) 143 ksi->ksi_code = CLD_DUMPED; 144 else 145 ksi->ksi_code = CLD_KILLED; 146 ksi->ksi_status = p->p_xsig; 147 } else { 148 ksi->ksi_code = CLD_EXITED; 149 ksi->ksi_status = p->p_xexit; 150 } 151 } else { 152 ksi->ksi_code = SI_USER; 153 ksi->ksi_status = p->p_xsig; 154 } 155 /* 156 * We fill those in, even for non-SIGCHLD. 157 * It's safe to access p->p_cred unlocked here. 158 */ 159 ksi->ksi_pid = p->p_pid; 160 ksi->ksi_uid = kauth_cred_geteuid(p->p_cred); 161 /* XXX: is this still valid? */ 162 ksi->ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; 163 ksi->ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; 164 } 165 166 /* 167 * exit -- 168 * Death of process. 169 */ 170 int 171 sys_exit(struct lwp *l, const struct sys_exit_args *uap, register_t *retval) 172 { 173 /* { 174 syscallarg(int) rval; 175 } */ 176 struct proc *p = l->l_proc; 177 178 /* Don't call exit1() multiple times in the same process. */ 179 mutex_enter(p->p_lock); 180 if (p->p_sflag & PS_WEXIT) { 181 mutex_exit(p->p_lock); 182 lwp_exit(l); 183 } 184 185 /* exit1() will release the mutex. */ 186 exit1(l, SCARG(uap, rval), 0); 187 /* NOTREACHED */ 188 return (0); 189 } 190 191 /* 192 * Exit: deallocate address space and other resources, change proc state 193 * to zombie, and unlink proc from allproc and parent's lists. Save exit 194 * status and rusage for wait(). Check for child processes and orphan them. 195 * 196 * Must be called with p->p_lock held. Does not return. 197 */ 198 void 199 exit1(struct lwp *l, int exitcode, int signo) 200 { 201 struct proc *p, *child, *next_child, *old_parent, *new_parent; 202 struct pgrp *pgrp; 203 ksiginfo_t ksi; 204 ksiginfoq_t kq; 205 int wakeinit; 206 207 p = l->l_proc; 208 209 KASSERT(mutex_owned(p->p_lock)); 210 KASSERT(p->p_vmspace != NULL); 211 212 if (__predict_false(p == initproc)) { 213 panic("init died (signal %d, exit %d)", signo, exitcode); 214 } 215 216 p->p_sflag |= PS_WEXIT; 217 218 /* 219 * Force all other LWPs to exit before we do. Only then can we 220 * begin to tear down the rest of the process state. 221 */ 222 if (p->p_nlwps > 1) { 223 exit_lwps(l); 224 } 225 226 ksiginfo_queue_init(&kq); 227 228 /* 229 * If we have been asked to stop on exit, do so now. 230 */ 231 if (__predict_false(p->p_sflag & PS_STOPEXIT)) { 232 KERNEL_UNLOCK_ALL(l, &l->l_biglocks); 233 sigclearall(p, &contsigmask, &kq); 234 235 if (!mutex_tryenter(proc_lock)) { 236 mutex_exit(p->p_lock); 237 mutex_enter(proc_lock); 238 mutex_enter(p->p_lock); 239 } 240 p->p_waited = 0; 241 p->p_pptr->p_nstopchild++; 242 p->p_stat = SSTOP; 243 mutex_exit(proc_lock); 244 lwp_lock(l); 245 p->p_nrlwps--; 246 l->l_stat = LSSTOP; 247 lwp_unlock(l); 248 mutex_exit(p->p_lock); 249 lwp_lock(l); 250 mi_switch(l); 251 KERNEL_LOCK(l->l_biglocks, l); 252 mutex_enter(p->p_lock); 253 } 254 255 /* 256 * Bin any remaining signals and mark the process as dying so it will 257 * not be found for, e.g. signals. 258 */ 259 sigfillset(&p->p_sigctx.ps_sigignore); 260 sigclearall(p, NULL, &kq); 261 p->p_stat = SDYING; 262 mutex_exit(p->p_lock); 263 ksiginfo_queue_drain(&kq); 264 265 /* Destroy any lwpctl info. */ 266 if (p->p_lwpctl != NULL) 267 lwp_ctl_exit(); 268 269 /* 270 * Drain all remaining references that procfs, ptrace and others may 271 * have on the process. 272 */ 273 rw_enter(&p->p_reflock, RW_WRITER); 274 275 DPRINTF(("%s: %d.%d exiting.\n", __func__, p->p_pid, l->l_lid)); 276 277 timers_free(p, TIMERS_ALL); 278 #if defined(__HAVE_RAS) 279 ras_purgeall(); 280 #endif 281 282 /* 283 * Close open files, release open-file table and free signal 284 * actions. This may block! 285 */ 286 fd_free(); 287 cwdfree(p->p_cwdi); 288 p->p_cwdi = NULL; 289 doexithooks(p); 290 sigactsfree(p->p_sigacts); 291 292 /* 293 * Write out accounting data. 294 */ 295 (void)acct_process(l); 296 297 #ifdef KTRACE 298 /* 299 * Release trace file. 300 */ 301 if (p->p_tracep != NULL) { 302 mutex_enter(&ktrace_lock); 303 ktrderef(p); 304 mutex_exit(&ktrace_lock); 305 } 306 #endif 307 308 p->p_xexit = exitcode; 309 p->p_xsig = signo; 310 311 /* 312 * If emulation has process exit hook, call it now. 313 * Set the exit status now so that the exit hook has 314 * an opportunity to tweak it (COMPAT_LINUX requires 315 * this for thread group emulation) 316 */ 317 if (p->p_emul->e_proc_exit) 318 (*p->p_emul->e_proc_exit)(p); 319 320 /* 321 * Free the VM resources we're still holding on to. 322 * We must do this from a valid thread because doing 323 * so may block. This frees vmspace, which we don't 324 * need anymore. The only remaining lwp is the one 325 * we run at this moment, nothing runs in userland 326 * anymore. 327 */ 328 uvm_proc_exit(p); 329 330 /* 331 * Stop profiling. 332 */ 333 if (__predict_false((p->p_stflag & PST_PROFIL) != 0)) { 334 mutex_spin_enter(&p->p_stmutex); 335 stopprofclock(p); 336 mutex_spin_exit(&p->p_stmutex); 337 } 338 339 /* 340 * If parent is waiting for us to exit or exec, PL_PPWAIT is set; we 341 * wake up the parent early to avoid deadlock. We can do this once 342 * the VM resources are released. 343 */ 344 mutex_enter(proc_lock); 345 if (p->p_lflag & PL_PPWAIT) { 346 #if 0 347 lwp_t *lp; 348 349 l->l_lwpctl = NULL; /* was on loan from blocked parent */ 350 p->p_lflag &= ~PL_PPWAIT; 351 352 lp = p->p_vforklwp; 353 p->p_vforklwp = NULL; 354 lp->l_pflag &= ~LP_VFORKWAIT; /* XXX */ 355 cv_broadcast(&lp->l_waitcv); 356 #else 357 l->l_lwpctl = NULL; /* was on loan from blocked parent */ 358 p->p_lflag &= ~PL_PPWAIT; 359 cv_broadcast(&p->p_pptr->p_waitcv); 360 #endif 361 } 362 363 if (SESS_LEADER(p)) { 364 struct vnode *vprele = NULL, *vprevoke = NULL; 365 struct session *sp = p->p_session; 366 struct tty *tp; 367 368 if (sp->s_ttyvp) { 369 /* 370 * Controlling process. 371 * Signal foreground pgrp, 372 * drain controlling terminal 373 * and revoke access to controlling terminal. 374 */ 375 tp = sp->s_ttyp; 376 mutex_spin_enter(&tty_lock); 377 if (tp->t_session == sp) { 378 /* we can't guarantee the revoke will do this */ 379 pgrp = tp->t_pgrp; 380 tp->t_pgrp = NULL; 381 tp->t_session = NULL; 382 mutex_spin_exit(&tty_lock); 383 if (pgrp != NULL) { 384 pgsignal(pgrp, SIGHUP, 1); 385 } 386 mutex_exit(proc_lock); 387 (void) ttywait(tp); 388 mutex_enter(proc_lock); 389 390 /* The tty could have been revoked. */ 391 vprevoke = sp->s_ttyvp; 392 } else 393 mutex_spin_exit(&tty_lock); 394 vprele = sp->s_ttyvp; 395 sp->s_ttyvp = NULL; 396 /* 397 * s_ttyp is not zero'd; we use this to indicate 398 * that the session once had a controlling terminal. 399 * (for logging and informational purposes) 400 */ 401 } 402 sp->s_leader = NULL; 403 404 if (vprevoke != NULL || vprele != NULL) { 405 if (vprevoke != NULL) { 406 /* Releases proc_lock. */ 407 proc_sessrele(sp); 408 VOP_REVOKE(vprevoke, REVOKEALL); 409 } else 410 mutex_exit(proc_lock); 411 if (vprele != NULL) 412 vrele(vprele); 413 mutex_enter(proc_lock); 414 } 415 } 416 fixjobc(p, p->p_pgrp, 0); 417 418 /* 419 * Finalize the last LWP's specificdata, as well as the 420 * specificdata for the proc itself. 421 */ 422 lwp_finispecific(l); 423 proc_finispecific(p); 424 425 /* 426 * Notify interested parties of our demise. 427 */ 428 KNOTE(&p->p_klist, NOTE_EXIT); 429 430 SDT_PROBE(proc, kernel, , exit, 431 ((p->p_sflag & PS_COREDUMP) ? CLD_DUMPED : 432 (p->p_xsig ? CLD_KILLED : CLD_EXITED)), 433 0,0,0,0); 434 435 #if PERFCTRS 436 /* 437 * Save final PMC information in parent process & clean up. 438 */ 439 if (PMC_ENABLED(p)) { 440 pmc_save_context(p); 441 pmc_accumulate(p->p_pptr, p); 442 pmc_process_exit(p); 443 } 444 #endif 445 446 /* 447 * Reset p_opptr pointer of all former children which got 448 * traced by another process and were reparented. We reset 449 * it to NULL here; the trace detach code then reparents 450 * the child to initproc. We only check allproc list, since 451 * eventual former children on zombproc list won't reference 452 * p_opptr anymore. 453 */ 454 if (__predict_false(p->p_slflag & PSL_CHTRACED)) { 455 struct proc *q; 456 PROCLIST_FOREACH(q, &allproc) { 457 if (q->p_opptr == p) 458 q->p_opptr = NULL; 459 } 460 } 461 462 /* 463 * Give orphaned children to init(8). 464 */ 465 child = LIST_FIRST(&p->p_children); 466 wakeinit = (child != NULL); 467 for (; child != NULL; child = next_child) { 468 next_child = LIST_NEXT(child, p_sibling); 469 470 /* 471 * Traced processes are killed since their existence 472 * means someone is screwing up. Since we reset the 473 * trace flags, the logic in sys_wait4() would not be 474 * triggered to reparent the process to its 475 * original parent, so we must do this here. 476 */ 477 if (__predict_false(child->p_slflag & PSL_TRACED)) { 478 mutex_enter(p->p_lock); 479 child->p_slflag &= 480 ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); 481 mutex_exit(p->p_lock); 482 if (child->p_opptr != child->p_pptr) { 483 struct proc *t = child->p_opptr; 484 proc_reparent(child, t ? t : initproc); 485 child->p_opptr = NULL; 486 } else 487 proc_reparent(child, initproc); 488 killproc(child, "orphaned traced process"); 489 } else 490 proc_reparent(child, initproc); 491 } 492 493 /* 494 * Move proc from allproc to zombproc, it's now nearly ready to be 495 * collected by parent. 496 */ 497 LIST_REMOVE(l, l_list); 498 LIST_REMOVE(p, p_list); 499 LIST_INSERT_HEAD(&zombproc, p, p_list); 500 501 /* 502 * Mark the process as dead. We must do this before we signal 503 * the parent. 504 */ 505 p->p_stat = SDEAD; 506 507 /* Put in front of parent's sibling list for parent to collect it */ 508 old_parent = p->p_pptr; 509 old_parent->p_nstopchild++; 510 if (LIST_FIRST(&old_parent->p_children) != p) { 511 /* Put child where it can be found quickly */ 512 LIST_REMOVE(p, p_sibling); 513 LIST_INSERT_HEAD(&old_parent->p_children, p, p_sibling); 514 } 515 516 /* 517 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 518 * flag set, notify init instead (and hope it will handle 519 * this situation). 520 */ 521 if (old_parent->p_flag & (PK_NOCLDWAIT|PK_CLDSIGIGN)) { 522 proc_reparent(p, initproc); 523 wakeinit = 1; 524 525 /* 526 * If this was the last child of our parent, notify 527 * parent, so in case he was wait(2)ing, he will 528 * continue. 529 */ 530 if (LIST_FIRST(&old_parent->p_children) == NULL) 531 cv_broadcast(&old_parent->p_waitcv); 532 } 533 534 /* Reload parent pointer, since p may have been reparented above */ 535 new_parent = p->p_pptr; 536 537 if (__predict_false((p->p_slflag & PSL_FSTRACE) == 0 && 538 p->p_exitsig != 0)) { 539 exit_psignal(p, new_parent, &ksi); 540 kpsignal(new_parent, &ksi, NULL); 541 } 542 543 /* Calculate the final rusage info. */ 544 calcru(p, &p->p_stats->p_ru.ru_utime, &p->p_stats->p_ru.ru_stime, 545 NULL, NULL); 546 547 if (wakeinit) 548 cv_broadcast(&initproc->p_waitcv); 549 550 callout_destroy(&l->l_timeout_ch); 551 552 /* 553 * Release any PCU resources before becoming a zombie. 554 */ 555 pcu_discard_all(l); 556 557 mutex_enter(p->p_lock); 558 /* Free the linux lwp id */ 559 if ((l->l_pflag & LP_PIDLID) != 0 && l->l_lid != p->p_pid) 560 proc_free_pid(l->l_lid); 561 lwp_drainrefs(l); 562 lwp_lock(l); 563 l->l_prflag &= ~LPR_DETACHED; 564 l->l_stat = LSZOMB; 565 lwp_unlock(l); 566 KASSERT(curlwp == l); 567 KASSERT(p->p_nrlwps == 1); 568 KASSERT(p->p_nlwps == 1); 569 p->p_stat = SZOMB; 570 p->p_nrlwps--; 571 p->p_nzlwps++; 572 p->p_ndlwps = 0; 573 mutex_exit(p->p_lock); 574 575 /* 576 * Signal the parent to collect us, and drop the proclist lock. 577 * Drop debugger/procfs lock; no new references can be gained. 578 */ 579 cv_broadcast(&p->p_pptr->p_waitcv); 580 rw_exit(&p->p_reflock); 581 mutex_exit(proc_lock); 582 583 /* Verify that we hold no locks other than the kernel lock. */ 584 LOCKDEBUG_BARRIER(&kernel_lock, 0); 585 586 /* 587 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 588 */ 589 590 /* 591 * Give machine-dependent code a chance to free any MD LWP 592 * resources. This must be done before uvm_lwp_exit(), in 593 * case these resources are in the PCB. 594 */ 595 cpu_lwp_free(l, 1); 596 597 pmap_deactivate(l); 598 599 /* This process no longer needs to hold the kernel lock. */ 600 #ifdef notyet 601 /* XXXSMP hold in lwp_userret() */ 602 KERNEL_UNLOCK_LAST(l); 603 #else 604 KERNEL_UNLOCK_ALL(l, NULL); 605 #endif 606 607 lwp_exit_switchaway(l); 608 } 609 610 void 611 exit_lwps(struct lwp *l) 612 { 613 proc_t *p = l->l_proc; 614 lwp_t *l2; 615 int nlocks; 616 617 KERNEL_UNLOCK_ALL(l, &nlocks); 618 retry: 619 KASSERT(mutex_owned(p->p_lock)); 620 621 /* 622 * Interrupt LWPs in interruptable sleep, unsuspend suspended 623 * LWPs and then wait for everyone else to finish. 624 */ 625 LIST_FOREACH(l2, &p->p_lwps, l_sibling) { 626 if (l2 == l) 627 continue; 628 lwp_lock(l2); 629 l2->l_flag |= LW_WEXIT; 630 if ((l2->l_stat == LSSLEEP && (l2->l_flag & LW_SINTR)) || 631 l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { 632 /* setrunnable() will release the lock. */ 633 setrunnable(l2); 634 continue; 635 } 636 lwp_unlock(l2); 637 } 638 639 /* 640 * Wait for every LWP to exit. Note: LWPs can get suspended/slept 641 * behind us or there may even be new LWPs created. Therefore, a 642 * full retry is required on error. 643 */ 644 while (p->p_nlwps > 1) { 645 if (lwp_wait(l, 0, NULL, true)) { 646 goto retry; 647 } 648 } 649 650 KERNEL_LOCK(nlocks, l); 651 KASSERT(p->p_nlwps == 1); 652 } 653 654 static int 655 do_sys_waitid(idtype_t idtype, id_t id, int *pid, int *status, int options, 656 struct wrusage *wru, siginfo_t *si) 657 { 658 proc_t *child; 659 int error; 660 661 662 if (wru != NULL) 663 memset(wru, 0, sizeof(*wru)); 664 if (si != NULL) 665 memset(si, 0, sizeof(*si)); 666 667 mutex_enter(proc_lock); 668 error = find_stopped_child(curproc, idtype, id, options, &child, 669 wru, si); 670 if (child == NULL) { 671 mutex_exit(proc_lock); 672 *pid = 0; 673 return error; 674 } 675 *pid = child->p_pid; 676 677 if (child->p_stat == SZOMB) { 678 /* Child is exiting */ 679 *status = P_WAITSTATUS(child); 680 /* proc_free() will release the proc_lock. */ 681 if (options & WNOWAIT) { 682 mutex_exit(proc_lock); 683 } else { 684 proc_free(child, wru); 685 } 686 } else { 687 /* Child state must have been SSTOP. */ 688 *status = child->p_xsig == SIGCONT ? W_CONTCODE() : 689 W_STOPCODE(child->p_xsig); 690 mutex_exit(proc_lock); 691 } 692 return 0; 693 } 694 695 int 696 do_sys_wait(int *pid, int *status, int options, struct rusage *ru) 697 { 698 idtype_t idtype; 699 id_t id; 700 int ret; 701 struct wrusage wru; 702 703 /* 704 * Translate the special pid values into the (idtype, pid) 705 * pair for wait6. The WAIT_MYPGRP case is handled by 706 * find_stopped_child() on its own. 707 */ 708 if (*pid == WAIT_ANY) { 709 idtype = P_ALL; 710 id = 0; 711 } else if (*pid < 0) { 712 idtype = P_PGID; 713 id = (id_t)-*pid; 714 } else { 715 idtype = P_PID; 716 id = (id_t)*pid; 717 } 718 options |= WEXITED | WTRAPPED; 719 ret = do_sys_waitid(idtype, id, pid, status, options, ru ? &wru : NULL, 720 NULL); 721 if (ru) 722 *ru = wru.wru_self; 723 return ret; 724 } 725 726 int 727 sys___wait450(struct lwp *l, const struct sys___wait450_args *uap, 728 register_t *retval) 729 { 730 /* { 731 syscallarg(int) pid; 732 syscallarg(int *) status; 733 syscallarg(int) options; 734 syscallarg(struct rusage *) rusage; 735 } */ 736 int error, status, pid = SCARG(uap, pid); 737 struct rusage ru; 738 739 error = do_sys_wait(&pid, &status, SCARG(uap, options), 740 SCARG(uap, rusage) != NULL ? &ru : NULL); 741 742 retval[0] = pid; 743 if (pid == 0) { 744 return error; 745 } 746 if (SCARG(uap, status)) { 747 error = copyout(&status, SCARG(uap, status), sizeof(status)); 748 } 749 if (SCARG(uap, rusage) && error == 0) { 750 error = copyout(&ru, SCARG(uap, rusage), sizeof(ru)); 751 } 752 return error; 753 } 754 755 int 756 sys_wait6(struct lwp *l, const struct sys_wait6_args *uap, register_t *retval) 757 { 758 /* { 759 syscallarg(idtype_t) idtype; 760 syscallarg(id_t) id; 761 syscallarg(int *) status; 762 syscallarg(int) options; 763 syscallarg(struct wrusage *) wru; 764 syscallarg(siginfo_t *) si; 765 } */ 766 struct wrusage wru, *wrup; 767 siginfo_t si, *sip; 768 idtype_t idtype; 769 int pid; 770 id_t id; 771 int error, status; 772 773 idtype = SCARG(uap, idtype); 774 id = SCARG(uap, id); 775 776 if (SCARG(uap, wru) != NULL) 777 wrup = &wru; 778 else 779 wrup = NULL; 780 781 if (SCARG(uap, info) != NULL) 782 sip = &si; 783 else 784 sip = NULL; 785 786 /* 787 * We expect all callers of wait6() to know about WEXITED and 788 * WTRAPPED. 789 */ 790 error = do_sys_waitid(idtype, id, &pid, &status, SCARG(uap, options), 791 wrup, sip); 792 793 retval[0] = pid; /* tell userland who it was */ 794 795 #if 0 796 /* 797 * should we copyout if there was no process, hence no useful data? 798 * We don't for an old sytle wait4() (etc) but I believe 799 * FreeBSD does for wait6(), so a tossup... Go with FreeBSD for now. 800 */ 801 if (pid == 0) 802 return error; 803 #endif 804 805 if (SCARG(uap, status) != NULL && error == 0) 806 error = copyout(&status, SCARG(uap, status), sizeof(status)); 807 if (SCARG(uap, wru) != NULL && error == 0) 808 error = copyout(&wru, SCARG(uap, wru), sizeof(wru)); 809 if (SCARG(uap, info) != NULL && error == 0) 810 error = copyout(&si, SCARG(uap, info), sizeof(si)); 811 return error; 812 } 813 814 815 /* 816 * Find a process that matches the provided criteria, and fill siginfo 817 * and resources if found. 818 * Returns: 819 * -1: Not found, abort early 820 * 0: Not matched 821 * 1: Matched, there might be more matches 822 * 2: This is the only match 823 */ 824 static int 825 match_process(struct proc *pp, struct proc **q, idtype_t idtype, id_t id, 826 int options, struct wrusage *wrusage, siginfo_t *siginfo) 827 { 828 struct rusage *rup; 829 struct proc *p = *q; 830 int rv = 1; 831 832 mutex_enter(p->p_lock); 833 switch (idtype) { 834 case P_ALL: 835 break; 836 case P_PID: 837 if (p->p_pid != (pid_t)id) { 838 mutex_exit(p->p_lock); 839 p = *q = proc_find_raw((pid_t)id); 840 if (p == NULL || p->p_stat == SIDL || p->p_pptr != pp) { 841 *q = NULL; 842 return -1; 843 } 844 mutex_enter(p->p_lock); 845 } 846 rv++; 847 break; 848 case P_PGID: 849 if (p->p_pgid != (pid_t)id) 850 goto out; 851 break; 852 case P_SID: 853 if (p->p_session->s_sid != (pid_t)id) 854 goto out; 855 break; 856 case P_UID: 857 if (kauth_cred_geteuid(p->p_cred) != (uid_t)id) 858 goto out; 859 break; 860 case P_GID: 861 if (kauth_cred_getegid(p->p_cred) != (gid_t)id) 862 goto out; 863 break; 864 case P_CID: 865 case P_PSETID: 866 case P_CPUID: 867 /* XXX: Implement me */ 868 default: 869 out: 870 mutex_exit(p->p_lock); 871 return 0; 872 } 873 874 if ((options & WEXITED) == 0 && p->p_stat == SZOMB) 875 goto out; 876 877 if (siginfo != NULL) { 878 siginfo->si_errno = 0; 879 880 /* 881 * SUSv4 requires that the si_signo value is always 882 * SIGCHLD. Obey it despite the rfork(2) interface 883 * allows to request other signal for child exit 884 * notification. 885 */ 886 siginfo->si_signo = SIGCHLD; 887 888 /* 889 * This is still a rough estimate. We will fix the 890 * cases TRAPPED, STOPPED, and CONTINUED later. 891 */ 892 if (p->p_sflag & PS_COREDUMP) { 893 siginfo->si_code = CLD_DUMPED; 894 siginfo->si_status = p->p_xsig; 895 } else if (p->p_xsig) { 896 siginfo->si_code = CLD_KILLED; 897 siginfo->si_status = p->p_xsig; 898 } else { 899 siginfo->si_code = CLD_EXITED; 900 siginfo->si_status = p->p_xexit; 901 } 902 903 siginfo->si_pid = p->p_pid; 904 siginfo->si_uid = kauth_cred_geteuid(p->p_cred); 905 siginfo->si_utime = p->p_stats->p_ru.ru_utime.tv_sec; 906 siginfo->si_stime = p->p_stats->p_ru.ru_stime.tv_sec; 907 } 908 909 /* 910 * There should be no reason to limit resources usage info to 911 * exited processes only. A snapshot about any resources used 912 * by a stopped process may be exactly what is needed. 913 */ 914 if (wrusage != NULL) { 915 rup = &wrusage->wru_self; 916 *rup = p->p_stats->p_ru; 917 calcru(p, &rup->ru_utime, &rup->ru_stime, NULL, NULL); 918 919 rup = &wrusage->wru_children; 920 *rup = p->p_stats->p_cru; 921 calcru(p, &rup->ru_utime, &rup->ru_stime, NULL, NULL); 922 } 923 924 mutex_exit(p->p_lock); 925 return rv; 926 } 927 928 /* 929 * Scan list of child processes for a child process that has stopped or 930 * exited. Used by sys_wait4 and 'compat' equivalents. 931 * 932 * Must be called with the proc_lock held, and may release while waiting. 933 */ 934 static int 935 find_stopped_child(struct proc *parent, idtype_t idtype, id_t id, int options, 936 struct proc **child_p, struct wrusage *wru, siginfo_t *si) 937 { 938 struct proc *child, *dead; 939 int error; 940 941 KASSERT(mutex_owned(proc_lock)); 942 943 if (options & ~(WUNTRACED|WNOHANG|WALTSIG|WALLSIG|WTRAPPED|WEXITED| 944 WNOWAIT|WCONTINUED) 945 && !(options & WOPTSCHECKED)) { 946 *child_p = NULL; 947 return EINVAL; 948 } 949 950 if ((options & (WEXITED|WUNTRACED|WCONTINUED|WTRAPPED)) == 0) { 951 /* 952 * We will be unable to find any matching processes, 953 * because there are no known events to look for. 954 * Prefer to return error instead of blocking 955 * indefinitely. 956 */ 957 *child_p = NULL; 958 return EINVAL; 959 } 960 961 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { 962 mutex_enter(parent->p_lock); 963 id = (id_t)parent->p_pgid; 964 mutex_exit(parent->p_lock); 965 idtype = P_PGID; 966 } 967 968 for (;;) { 969 error = ECHILD; 970 dead = NULL; 971 972 LIST_FOREACH(child, &parent->p_children, p_sibling) { 973 int rv = match_process(parent, &child, idtype, id, 974 options, wru, si); 975 if (rv == -1) 976 break; 977 if (rv == 0) 978 continue; 979 980 /* 981 * Wait for processes with p_exitsig != SIGCHLD 982 * processes only if WALTSIG is set; wait for 983 * processes with p_exitsig == SIGCHLD only 984 * if WALTSIG is clear. 985 */ 986 if (((options & WALLSIG) == 0) && 987 (options & WALTSIG ? child->p_exitsig == SIGCHLD 988 : P_EXITSIG(child) != SIGCHLD)){ 989 if (rv == 2) { 990 child = NULL; 991 break; 992 } 993 continue; 994 } 995 996 error = 0; 997 if ((options & WNOZOMBIE) == 0) { 998 if (child->p_stat == SZOMB) 999 break; 1000 if (child->p_stat == SDEAD) { 1001 /* 1002 * We may occasionally arrive here 1003 * after receiving a signal, but 1004 * immediately before the child 1005 * process is zombified. The wait 1006 * will be short, so avoid returning 1007 * to userspace. 1008 */ 1009 dead = child; 1010 } 1011 } 1012 1013 if ((options & WCONTINUED) != 0 && 1014 child->p_xsig == SIGCONT && 1015 (child->p_sflag & PS_CONTINUED)) { 1016 if ((options & WNOWAIT) == 0) { 1017 child->p_sflag &= ~PS_CONTINUED; 1018 child->p_waited = 1; 1019 parent->p_nstopchild--; 1020 } 1021 if (si) { 1022 si->si_status = child->p_xsig; 1023 si->si_code = CLD_CONTINUED; 1024 } 1025 break; 1026 } 1027 1028 if ((options & (WTRAPPED|WSTOPPED)) != 0 && 1029 child->p_stat == SSTOP && 1030 child->p_waited == 0 && 1031 ((child->p_slflag & PSL_TRACED) || 1032 options & (WUNTRACED|WSTOPPED))) { 1033 if ((options & WNOWAIT) == 0) { 1034 child->p_waited = 1; 1035 parent->p_nstopchild--; 1036 } 1037 if (si) { 1038 si->si_status = child->p_xsig; 1039 si->si_code = 1040 (child->p_slflag & PSL_TRACED) ? 1041 CLD_TRAPPED : CLD_STOPPED; 1042 } 1043 break; 1044 } 1045 if (parent->p_nstopchild == 0 || rv == 2) { 1046 child = NULL; 1047 break; 1048 } 1049 } 1050 1051 if (child != NULL || error != 0 || 1052 ((options & WNOHANG) != 0 && dead == NULL)) { 1053 *child_p = child; 1054 return error; 1055 } 1056 1057 /* 1058 * Wait for another child process to stop. 1059 */ 1060 error = cv_wait_sig(&parent->p_waitcv, proc_lock); 1061 1062 if (error != 0) { 1063 *child_p = NULL; 1064 return error; 1065 } 1066 } 1067 } 1068 1069 /* 1070 * Free a process after parent has taken all the state info. Must be called 1071 * with the proclist lock held, and will release before returning. 1072 * 1073 * *ru is returned to the caller, and must be freed by the caller. 1074 */ 1075 static void 1076 proc_free(struct proc *p, struct wrusage *wru) 1077 { 1078 struct proc *parent = p->p_pptr; 1079 struct lwp *l; 1080 ksiginfo_t ksi; 1081 kauth_cred_t cred1, cred2; 1082 uid_t uid; 1083 1084 KASSERT(mutex_owned(proc_lock)); 1085 KASSERT(p->p_nlwps == 1); 1086 KASSERT(p->p_nzlwps == 1); 1087 KASSERT(p->p_nrlwps == 0); 1088 KASSERT(p->p_stat == SZOMB); 1089 1090 /* 1091 * If we got the child via ptrace(2) or procfs, and 1092 * the parent is different (meaning the process was 1093 * attached, rather than run as a child), then we need 1094 * to give it back to the old parent, and send the 1095 * parent the exit signal. The rest of the cleanup 1096 * will be done when the old parent waits on the child. 1097 */ 1098 if ((p->p_slflag & PSL_TRACED) != 0 && p->p_opptr != parent) { 1099 mutex_enter(p->p_lock); 1100 p->p_slflag &= ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); 1101 mutex_exit(p->p_lock); 1102 parent = (p->p_opptr == NULL) ? initproc : p->p_opptr; 1103 proc_reparent(p, parent); 1104 p->p_opptr = NULL; 1105 if (p->p_exitsig != 0) { 1106 exit_psignal(p, parent, &ksi); 1107 kpsignal(parent, &ksi, NULL); 1108 } 1109 cv_broadcast(&parent->p_waitcv); 1110 mutex_exit(proc_lock); 1111 return; 1112 } 1113 1114 sched_proc_exit(parent, p); 1115 1116 /* 1117 * Add child times of exiting process onto its own times. 1118 * This cannot be done any earlier else it might get done twice. 1119 */ 1120 l = LIST_FIRST(&p->p_lwps); 1121 p->p_stats->p_ru.ru_nvcsw += (l->l_ncsw - l->l_nivcsw); 1122 p->p_stats->p_ru.ru_nivcsw += l->l_nivcsw; 1123 ruadd(&p->p_stats->p_ru, &l->l_ru); 1124 ruadd(&p->p_stats->p_ru, &p->p_stats->p_cru); 1125 ruadd(&parent->p_stats->p_cru, &p->p_stats->p_ru); 1126 if (wru != NULL) { 1127 wru->wru_self = p->p_stats->p_ru; 1128 wru->wru_children = p->p_stats->p_cru; 1129 } 1130 p->p_xsig = 0; 1131 p->p_xexit = 0; 1132 1133 /* 1134 * At this point we are going to start freeing the final resources. 1135 * If anyone tries to access the proc structure after here they will 1136 * get a shock - bits are missing. Attempt to make it hard! We 1137 * don't bother with any further locking past this point. 1138 */ 1139 p->p_stat = SIDL; /* not even a zombie any more */ 1140 LIST_REMOVE(p, p_list); /* off zombproc */ 1141 parent->p_nstopchild--; 1142 LIST_REMOVE(p, p_sibling); 1143 1144 /* 1145 * Let pid be reallocated. 1146 */ 1147 proc_free_pid(p->p_pid); 1148 1149 /* 1150 * Unlink process from its process group. 1151 * Releases the proc_lock. 1152 */ 1153 proc_leavepgrp(p); 1154 1155 /* 1156 * Delay release until after lwp_free. 1157 */ 1158 cred2 = l->l_cred; 1159 1160 /* 1161 * Free the last LWP's resources. 1162 * 1163 * lwp_free ensures the LWP is no longer running on another CPU. 1164 */ 1165 lwp_free(l, false, true); 1166 1167 /* 1168 * Now no one except us can reach the process p. 1169 */ 1170 1171 /* 1172 * Decrement the count of procs running with this uid. 1173 */ 1174 cred1 = p->p_cred; 1175 uid = kauth_cred_getuid(cred1); 1176 (void)chgproccnt(uid, -1); 1177 1178 /* 1179 * Release substructures. 1180 */ 1181 1182 lim_free(p->p_limit); 1183 pstatsfree(p->p_stats); 1184 kauth_cred_free(cred1); 1185 kauth_cred_free(cred2); 1186 1187 /* 1188 * Release reference to text vnode 1189 */ 1190 if (p->p_textvp) 1191 vrele(p->p_textvp); 1192 1193 mutex_destroy(&p->p_auxlock); 1194 mutex_obj_free(p->p_lock); 1195 mutex_destroy(&p->p_stmutex); 1196 cv_destroy(&p->p_waitcv); 1197 cv_destroy(&p->p_lwpcv); 1198 rw_destroy(&p->p_reflock); 1199 1200 proc_free_mem(p); 1201 } 1202 1203 /* 1204 * make process 'parent' the new parent of process 'child'. 1205 * 1206 * Must be called with proc_lock held. 1207 */ 1208 void 1209 proc_reparent(struct proc *child, struct proc *parent) 1210 { 1211 1212 KASSERT(mutex_owned(proc_lock)); 1213 1214 if (child->p_pptr == parent) 1215 return; 1216 1217 if (child->p_stat == SZOMB || child->p_stat == SDEAD || 1218 (child->p_stat == SSTOP && !child->p_waited)) { 1219 child->p_pptr->p_nstopchild--; 1220 parent->p_nstopchild++; 1221 } 1222 if (parent == initproc) 1223 child->p_exitsig = SIGCHLD; 1224 1225 LIST_REMOVE(child, p_sibling); 1226 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1227 child->p_pptr = parent; 1228 child->p_ppid = parent->p_pid; 1229 } 1230