1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 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 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_ddb.h" 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/sysproto.h> 48 #include <sys/capsicum.h> 49 #include <sys/eventhandler.h> 50 #include <sys/kernel.h> 51 #include <sys/ktr.h> 52 #include <sys/malloc.h> 53 #include <sys/lock.h> 54 #include <sys/mutex.h> 55 #include <sys/proc.h> 56 #include <sys/procdesc.h> 57 #include <sys/jail.h> 58 #include <sys/tty.h> 59 #include <sys/wait.h> 60 #include <sys/vmmeter.h> 61 #include <sys/vnode.h> 62 #include <sys/racct.h> 63 #include <sys/resourcevar.h> 64 #include <sys/sbuf.h> 65 #include <sys/signalvar.h> 66 #include <sys/sched.h> 67 #include <sys/sx.h> 68 #include <sys/syscallsubr.h> 69 #include <sys/sysctl.h> 70 #include <sys/syslog.h> 71 #include <sys/ptrace.h> 72 #include <sys/acct.h> /* for acct_process() function prototype */ 73 #include <sys/filedesc.h> 74 #include <sys/sdt.h> 75 #include <sys/shm.h> 76 #include <sys/sem.h> 77 #include <sys/sysent.h> 78 #include <sys/timers.h> 79 #include <sys/umtxvar.h> 80 #ifdef KTRACE 81 #include <sys/ktrace.h> 82 #endif 83 84 #include <security/audit/audit.h> 85 #include <security/mac/mac_framework.h> 86 87 #include <vm/vm.h> 88 #include <vm/vm_extern.h> 89 #include <vm/vm_param.h> 90 #include <vm/pmap.h> 91 #include <vm/vm_map.h> 92 #include <vm/vm_page.h> 93 #include <vm/uma.h> 94 95 #ifdef KDTRACE_HOOKS 96 #include <sys/dtrace_bsd.h> 97 dtrace_execexit_func_t dtrace_fasttrap_exit; 98 #endif 99 100 SDT_PROVIDER_DECLARE(proc); 101 SDT_PROBE_DEFINE1(proc, , , exit, "int"); 102 103 static int kern_kill_on_dbg_exit = 1; 104 SYSCTL_INT(_kern, OID_AUTO, kill_on_debugger_exit, CTLFLAG_RWTUN, 105 &kern_kill_on_dbg_exit, 0, 106 "Kill ptraced processes when debugger exits"); 107 108 static bool kern_wait_dequeue_sigchld = 1; 109 SYSCTL_BOOL(_kern, OID_AUTO, wait_dequeue_sigchld, CTLFLAG_RWTUN, 110 &kern_wait_dequeue_sigchld, 0, 111 "Dequeue SIGCHLD on wait(2) for live process"); 112 113 struct proc * 114 proc_realparent(struct proc *child) 115 { 116 struct proc *p, *parent; 117 118 sx_assert(&proctree_lock, SX_LOCKED); 119 if ((child->p_treeflag & P_TREE_ORPHANED) == 0) 120 return (child->p_pptr->p_pid == child->p_oppid ? 121 child->p_pptr : child->p_reaper); 122 for (p = child; (p->p_treeflag & P_TREE_FIRST_ORPHAN) == 0;) { 123 /* Cannot use LIST_PREV(), since the list head is not known. */ 124 p = __containerof(p->p_orphan.le_prev, struct proc, 125 p_orphan.le_next); 126 KASSERT((p->p_treeflag & P_TREE_ORPHANED) != 0, 127 ("missing P_ORPHAN %p", p)); 128 } 129 parent = __containerof(p->p_orphan.le_prev, struct proc, 130 p_orphans.lh_first); 131 return (parent); 132 } 133 134 void 135 reaper_abandon_children(struct proc *p, bool exiting) 136 { 137 struct proc *p1, *p2, *ptmp; 138 139 sx_assert(&proctree_lock, SX_XLOCKED); 140 KASSERT(p != initproc, ("reaper_abandon_children for initproc")); 141 if ((p->p_treeflag & P_TREE_REAPER) == 0) 142 return; 143 p1 = p->p_reaper; 144 LIST_FOREACH_SAFE(p2, &p->p_reaplist, p_reapsibling, ptmp) { 145 LIST_REMOVE(p2, p_reapsibling); 146 p2->p_reaper = p1; 147 p2->p_reapsubtree = p->p_reapsubtree; 148 LIST_INSERT_HEAD(&p1->p_reaplist, p2, p_reapsibling); 149 if (exiting && p2->p_pptr == p) { 150 PROC_LOCK(p2); 151 proc_reparent(p2, p1, true); 152 PROC_UNLOCK(p2); 153 } 154 } 155 KASSERT(LIST_EMPTY(&p->p_reaplist), ("p_reaplist not empty")); 156 p->p_treeflag &= ~P_TREE_REAPER; 157 } 158 159 static void 160 reaper_clear(struct proc *p) 161 { 162 struct proc *p1; 163 bool clear; 164 165 sx_assert(&proctree_lock, SX_LOCKED); 166 LIST_REMOVE(p, p_reapsibling); 167 if (p->p_reapsubtree == 1) 168 return; 169 clear = true; 170 LIST_FOREACH(p1, &p->p_reaper->p_reaplist, p_reapsibling) { 171 if (p1->p_reapsubtree == p->p_reapsubtree) { 172 clear = false; 173 break; 174 } 175 } 176 if (clear) 177 proc_id_clear(PROC_ID_REAP, p->p_reapsubtree); 178 } 179 180 void 181 proc_clear_orphan(struct proc *p) 182 { 183 struct proc *p1; 184 185 sx_assert(&proctree_lock, SA_XLOCKED); 186 if ((p->p_treeflag & P_TREE_ORPHANED) == 0) 187 return; 188 if ((p->p_treeflag & P_TREE_FIRST_ORPHAN) != 0) { 189 p1 = LIST_NEXT(p, p_orphan); 190 if (p1 != NULL) 191 p1->p_treeflag |= P_TREE_FIRST_ORPHAN; 192 p->p_treeflag &= ~P_TREE_FIRST_ORPHAN; 193 } 194 LIST_REMOVE(p, p_orphan); 195 p->p_treeflag &= ~P_TREE_ORPHANED; 196 } 197 198 void 199 exit_onexit(struct proc *p) 200 { 201 MPASS(p->p_numthreads == 1); 202 umtx_thread_exit(FIRST_THREAD_IN_PROC(p)); 203 } 204 205 /* 206 * exit -- death of process. 207 */ 208 int 209 sys_exit(struct thread *td, struct exit_args *uap) 210 { 211 212 exit1(td, uap->rval, 0); 213 __unreachable(); 214 } 215 216 void 217 proc_set_p2_wexit(struct proc *p) 218 { 219 PROC_LOCK_ASSERT(p, MA_OWNED); 220 p->p_flag2 |= P2_WEXIT; 221 } 222 223 /* 224 * Exit: deallocate address space and other resources, change proc state to 225 * zombie, and unlink proc from allproc and parent's lists. Save exit status 226 * and rusage for wait(). Check for child processes and orphan them. 227 */ 228 void 229 exit1(struct thread *td, int rval, int signo) 230 { 231 struct proc *p, *nq, *q, *t; 232 struct thread *tdt; 233 ksiginfo_t *ksi, *ksi1; 234 int signal_parent; 235 236 mtx_assert(&Giant, MA_NOTOWNED); 237 KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo)); 238 TSPROCEXIT(td->td_proc->p_pid); 239 240 p = td->td_proc; 241 /* 242 * In case we're rebooting we just let init die in order to 243 * work around an issues where pid 1 might get a fatal signal. 244 * For instance, if network interface serving NFS root is 245 * going down due to reboot, page-in requests for text are 246 * failing. 247 */ 248 if (p == initproc && rebooting == 0) { 249 printf("init died (signal %d, exit %d)\n", signo, rval); 250 panic("Going nowhere without my init!"); 251 } 252 253 /* 254 * Process deferred operations, designated with ASTF_KCLEAR. 255 * For instance, we need to deref SU mp, since the thread does 256 * not return to userspace, and wait for geom to stabilize. 257 */ 258 ast_kclear(td); 259 260 /* 261 * MUST abort all other threads before proceeding past here. 262 */ 263 PROC_LOCK(p); 264 proc_set_p2_wexit(p); 265 266 /* 267 * First check if some other thread or external request got 268 * here before us. If so, act appropriately: exit or suspend. 269 * We must ensure that stop requests are handled before we set 270 * P_WEXIT. 271 */ 272 thread_suspend_check(0); 273 while (p->p_flag & P_HADTHREADS) { 274 /* 275 * Kill off the other threads. This requires 276 * some co-operation from other parts of the kernel 277 * so it may not be instantaneous. With this state set 278 * any thread attempting to interruptibly 279 * sleep will return immediately with EINTR or EWOULDBLOCK 280 * which will hopefully force them to back out to userland 281 * freeing resources as they go. Any thread attempting 282 * to return to userland will thread_exit() from ast(). 283 * thread_exit() will unsuspend us when the last of the 284 * other threads exits. 285 * If there is already a thread singler after resumption, 286 * calling thread_single() will fail; in that case, we just 287 * re-check all suspension request, the thread should 288 * either be suspended there or exit. 289 */ 290 if (!thread_single(p, SINGLE_EXIT)) 291 /* 292 * All other activity in this process is now 293 * stopped. Threading support has been turned 294 * off. 295 */ 296 break; 297 /* 298 * Recheck for new stop or suspend requests which 299 * might appear while process lock was dropped in 300 * thread_single(). 301 */ 302 thread_suspend_check(0); 303 } 304 KASSERT(p->p_numthreads == 1, 305 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 306 racct_sub(p, RACCT_NTHR, 1); 307 308 /* Let event handler change exit status */ 309 p->p_xexit = rval; 310 p->p_xsig = signo; 311 312 /* 313 * Ignore any pending request to stop due to a stop signal. 314 * Once P_WEXIT is set, future requests will be ignored as 315 * well. 316 */ 317 p->p_flag &= ~P_STOPPED_SIG; 318 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped")); 319 320 /* Note that we are exiting. */ 321 p->p_flag |= P_WEXIT; 322 323 /* 324 * Wait for any processes that have a hold on our vmspace to 325 * release their reference. 326 */ 327 while (p->p_lock > 0) 328 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 329 330 PROC_UNLOCK(p); 331 /* Drain the limit callout while we don't have the proc locked */ 332 callout_drain(&p->p_limco); 333 334 #ifdef AUDIT 335 /* 336 * The Sun BSM exit token contains two components: an exit status as 337 * passed to exit(), and a return value to indicate what sort of exit 338 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 339 * what the return value is. 340 */ 341 AUDIT_ARG_EXIT(rval, 0); 342 AUDIT_SYSCALL_EXIT(0, td); 343 #endif 344 345 /* Are we a task leader with peers? */ 346 if (p->p_peers != NULL && p == p->p_leader) { 347 mtx_lock(&ppeers_lock); 348 q = p->p_peers; 349 while (q != NULL) { 350 PROC_LOCK(q); 351 kern_psignal(q, SIGKILL); 352 PROC_UNLOCK(q); 353 q = q->p_peers; 354 } 355 while (p->p_peers != NULL) 356 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 357 mtx_unlock(&ppeers_lock); 358 } 359 360 itimers_exit(p); 361 362 /* 363 * Check if any loadable modules need anything done at process exit. 364 * E.g. SYSV IPC stuff. 365 * Event handler could change exit status. 366 * XXX what if one of these generates an error? 367 */ 368 EVENTHANDLER_DIRECT_INVOKE(process_exit, p); 369 370 /* 371 * If parent is waiting for us to exit or exec, 372 * P_PPWAIT is set; we will wakeup the parent below. 373 */ 374 PROC_LOCK(p); 375 stopprofclock(p); 376 p->p_ptevents = 0; 377 378 /* 379 * Stop the real interval timer. If the handler is currently 380 * executing, prevent it from rearming itself and let it finish. 381 */ 382 if (timevalisset(&p->p_realtimer.it_value) && 383 callout_stop(&p->p_itcallout) == 0) { 384 timevalclear(&p->p_realtimer.it_interval); 385 PROC_UNLOCK(p); 386 callout_drain(&p->p_itcallout); 387 } else { 388 PROC_UNLOCK(p); 389 } 390 391 if (p->p_sysent->sv_onexit != NULL) 392 p->p_sysent->sv_onexit(p); 393 seltdfini(td); 394 395 /* 396 * Reset any sigio structures pointing to us as a result of 397 * F_SETOWN with our pid. The P_WEXIT flag interlocks with fsetown(). 398 */ 399 funsetownlst(&p->p_sigiolst); 400 401 /* 402 * Close open files and release open-file table. 403 * This may block! 404 */ 405 pdescfree(td); 406 fdescfree(td); 407 408 /* 409 * Remove ourself from our leader's peer list and wake our leader. 410 */ 411 if (p->p_leader->p_peers != NULL) { 412 mtx_lock(&ppeers_lock); 413 if (p->p_leader->p_peers != NULL) { 414 q = p->p_leader; 415 while (q->p_peers != p) 416 q = q->p_peers; 417 q->p_peers = p->p_peers; 418 wakeup(p->p_leader); 419 } 420 mtx_unlock(&ppeers_lock); 421 } 422 423 exec_free_abi_mappings(p); 424 vmspace_exit(td); 425 (void)acct_process(td); 426 427 #ifdef KTRACE 428 ktrprocexit(td); 429 #endif 430 /* 431 * Release reference to text vnode etc 432 */ 433 if (p->p_textvp != NULL) { 434 vrele(p->p_textvp); 435 p->p_textvp = NULL; 436 } 437 if (p->p_textdvp != NULL) { 438 vrele(p->p_textdvp); 439 p->p_textdvp = NULL; 440 } 441 if (p->p_binname != NULL) { 442 free(p->p_binname, M_PARGS); 443 p->p_binname = NULL; 444 } 445 446 /* 447 * Release our limits structure. 448 */ 449 lim_free(p->p_limit); 450 p->p_limit = NULL; 451 452 tidhash_remove(td); 453 454 /* 455 * Call machine-dependent code to release any 456 * machine-dependent resources other than the address space. 457 * The address space is released by "vmspace_exitfree(p)" in 458 * vm_waitproc(). 459 */ 460 cpu_exit(td); 461 462 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 463 464 /* 465 * Remove from allproc. It still sits in the hash. 466 */ 467 sx_xlock(&allproc_lock); 468 LIST_REMOVE(p, p_list); 469 470 #ifdef DDB 471 /* 472 * Used by ddb's 'ps' command to find this process via the 473 * pidhash. 474 */ 475 p->p_list.le_prev = NULL; 476 #endif 477 prison_proc_unlink(p->p_ucred->cr_prison, p); 478 sx_xunlock(&allproc_lock); 479 480 sx_xlock(&proctree_lock); 481 if ((p->p_flag & (P_TRACED | P_PPWAIT | P_PPTRACE)) != 0) { 482 PROC_LOCK(p); 483 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE); 484 PROC_UNLOCK(p); 485 } 486 487 /* 488 * killjobc() might drop and re-acquire proctree_lock to 489 * revoke control tty if exiting process was a session leader. 490 */ 491 killjobc(); 492 493 /* 494 * Reparent all children processes: 495 * - traced ones to the original parent (or init if we are that parent) 496 * - the rest to init 497 */ 498 q = LIST_FIRST(&p->p_children); 499 if (q != NULL) /* only need this if any child is S_ZOMB */ 500 wakeup(q->p_reaper); 501 for (; q != NULL; q = nq) { 502 nq = LIST_NEXT(q, p_sibling); 503 ksi = ksiginfo_alloc(M_WAITOK); 504 PROC_LOCK(q); 505 q->p_sigparent = SIGCHLD; 506 507 if ((q->p_flag & P_TRACED) == 0) { 508 proc_reparent(q, q->p_reaper, true); 509 if (q->p_state == PRS_ZOMBIE) { 510 /* 511 * Inform reaper about the reparented 512 * zombie, since wait(2) has something 513 * new to report. Guarantee queueing 514 * of the SIGCHLD signal, similar to 515 * the _exit() behaviour, by providing 516 * our ksiginfo. Ksi is freed by the 517 * signal delivery. 518 */ 519 if (q->p_ksi == NULL) { 520 ksi1 = NULL; 521 } else { 522 ksiginfo_copy(q->p_ksi, ksi); 523 ksi->ksi_flags |= KSI_INS; 524 ksi1 = ksi; 525 ksi = NULL; 526 } 527 PROC_LOCK(q->p_reaper); 528 pksignal(q->p_reaper, SIGCHLD, ksi1); 529 PROC_UNLOCK(q->p_reaper); 530 } else if (q->p_pdeathsig > 0) { 531 /* 532 * The child asked to received a signal 533 * when we exit. 534 */ 535 kern_psignal(q, q->p_pdeathsig); 536 } 537 } else { 538 /* 539 * Traced processes are killed by default 540 * since their existence means someone is 541 * screwing up. 542 */ 543 t = proc_realparent(q); 544 if (t == p) { 545 proc_reparent(q, q->p_reaper, true); 546 } else { 547 PROC_LOCK(t); 548 proc_reparent(q, t, true); 549 PROC_UNLOCK(t); 550 } 551 /* 552 * Since q was found on our children list, the 553 * proc_reparent() call moved q to the orphan 554 * list due to present P_TRACED flag. Clear 555 * orphan link for q now while q is locked. 556 */ 557 proc_clear_orphan(q); 558 q->p_flag &= ~P_TRACED; 559 q->p_flag2 &= ~P2_PTRACE_FSTP; 560 q->p_ptevents = 0; 561 p->p_xthread = NULL; 562 FOREACH_THREAD_IN_PROC(q, tdt) { 563 tdt->td_dbgflags &= ~(TDB_SUSPEND | TDB_XSIG | 564 TDB_FSTP); 565 tdt->td_xsig = 0; 566 } 567 if (kern_kill_on_dbg_exit) { 568 q->p_flag &= ~P_STOPPED_TRACE; 569 kern_psignal(q, SIGKILL); 570 } else if ((q->p_flag & (P_STOPPED_TRACE | 571 P_STOPPED_SIG)) != 0) { 572 sigqueue_delete_proc(q, SIGTRAP); 573 ptrace_unsuspend(q); 574 } 575 } 576 PROC_UNLOCK(q); 577 if (ksi != NULL) 578 ksiginfo_free(ksi); 579 } 580 581 /* 582 * Also get rid of our orphans. 583 */ 584 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) { 585 PROC_LOCK(q); 586 KASSERT(q->p_oppid == p->p_pid, 587 ("orphan %p of %p has unexpected oppid %d", q, p, 588 q->p_oppid)); 589 q->p_oppid = q->p_reaper->p_pid; 590 591 /* 592 * If we are the real parent of this process 593 * but it has been reparented to a debugger, then 594 * check if it asked for a signal when we exit. 595 */ 596 if (q->p_pdeathsig > 0) 597 kern_psignal(q, q->p_pdeathsig); 598 CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid, 599 q->p_pid); 600 proc_clear_orphan(q); 601 PROC_UNLOCK(q); 602 } 603 604 #ifdef KDTRACE_HOOKS 605 if (SDT_PROBES_ENABLED()) { 606 int reason = CLD_EXITED; 607 if (WCOREDUMP(signo)) 608 reason = CLD_DUMPED; 609 else if (WIFSIGNALED(signo)) 610 reason = CLD_KILLED; 611 SDT_PROBE1(proc, , , exit, reason); 612 } 613 #endif 614 615 /* Save exit status. */ 616 PROC_LOCK(p); 617 p->p_xthread = td; 618 619 if (p->p_sysent->sv_ontdexit != NULL) 620 p->p_sysent->sv_ontdexit(td); 621 622 #ifdef KDTRACE_HOOKS 623 /* 624 * Tell the DTrace fasttrap provider about the exit if it 625 * has declared an interest. 626 */ 627 if (dtrace_fasttrap_exit) 628 dtrace_fasttrap_exit(p); 629 #endif 630 631 /* 632 * Notify interested parties of our demise. 633 */ 634 KNOTE_LOCKED(p->p_klist, NOTE_EXIT); 635 636 /* 637 * If this is a process with a descriptor, we may not need to deliver 638 * a signal to the parent. proctree_lock is held over 639 * procdesc_exit() to serialize concurrent calls to close() and 640 * exit(). 641 */ 642 signal_parent = 0; 643 if (p->p_procdesc == NULL || procdesc_exit(p)) { 644 /* 645 * Notify parent that we're gone. If parent has the 646 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN, 647 * notify process 1 instead (and hope it will handle this 648 * situation). 649 */ 650 PROC_LOCK(p->p_pptr); 651 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 652 if (p->p_pptr->p_sigacts->ps_flag & 653 (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 654 struct proc *pp; 655 656 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 657 pp = p->p_pptr; 658 PROC_UNLOCK(pp); 659 proc_reparent(p, p->p_reaper, true); 660 p->p_sigparent = SIGCHLD; 661 PROC_LOCK(p->p_pptr); 662 663 /* 664 * Notify parent, so in case he was wait(2)ing or 665 * executing waitpid(2) with our pid, he will 666 * continue. 667 */ 668 wakeup(pp); 669 } else 670 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 671 672 if (p->p_pptr == p->p_reaper || p->p_pptr == initproc) { 673 signal_parent = 1; 674 } else if (p->p_sigparent != 0) { 675 if (p->p_sigparent == SIGCHLD) { 676 signal_parent = 1; 677 } else { /* LINUX thread */ 678 signal_parent = 2; 679 } 680 } 681 } else 682 PROC_LOCK(p->p_pptr); 683 sx_xunlock(&proctree_lock); 684 685 if (signal_parent == 1) { 686 childproc_exited(p); 687 } else if (signal_parent == 2) { 688 kern_psignal(p->p_pptr, p->p_sigparent); 689 } 690 691 /* Tell the prison that we are gone. */ 692 prison_proc_free(p->p_ucred->cr_prison); 693 694 /* 695 * The state PRS_ZOMBIE prevents other processes from sending 696 * signal to the process, to avoid memory leak, we free memory 697 * for signal queue at the time when the state is set. 698 */ 699 sigqueue_flush(&p->p_sigqueue); 700 sigqueue_flush(&td->td_sigqueue); 701 702 /* 703 * We have to wait until after acquiring all locks before 704 * changing p_state. We need to avoid all possible context 705 * switches (including ones from blocking on a mutex) while 706 * marked as a zombie. We also have to set the zombie state 707 * before we release the parent process' proc lock to avoid 708 * a lost wakeup. So, we first call wakeup, then we grab the 709 * sched lock, update the state, and release the parent process' 710 * proc lock. 711 */ 712 wakeup(p->p_pptr); 713 cv_broadcast(&p->p_pwait); 714 sched_exit(p->p_pptr, td); 715 PROC_SLOCK(p); 716 p->p_state = PRS_ZOMBIE; 717 PROC_UNLOCK(p->p_pptr); 718 719 /* 720 * Save our children's rusage information in our exit rusage. 721 */ 722 PROC_STATLOCK(p); 723 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 724 PROC_STATUNLOCK(p); 725 726 /* 727 * Make sure the scheduler takes this thread out of its tables etc. 728 * This will also release this thread's reference to the ucred. 729 * Other thread parts to release include pcb bits and such. 730 */ 731 thread_exit(); 732 } 733 734 #ifndef _SYS_SYSPROTO_H_ 735 struct abort2_args { 736 char *why; 737 int nargs; 738 void **args; 739 }; 740 #endif 741 742 int 743 sys_abort2(struct thread *td, struct abort2_args *uap) 744 { 745 void *uargs[16]; 746 void **uargsp; 747 int error, nargs; 748 749 nargs = uap->nargs; 750 if (nargs < 0 || nargs > nitems(uargs)) 751 nargs = -1; 752 uargsp = NULL; 753 if (nargs > 0) { 754 if (uap->args != NULL) { 755 error = copyin(uap->args, uargs, 756 nargs * sizeof(void *)); 757 if (error != 0) 758 nargs = -1; 759 else 760 uargsp = uargs; 761 } else 762 nargs = -1; 763 } 764 return (kern_abort2(td, uap->why, nargs, uargsp)); 765 } 766 767 /* 768 * kern_abort2() 769 * Arguments: 770 * why - user pointer to why 771 * nargs - number of arguments copied or -1 if an error occurred in copying 772 * args - pointer to an array of pointers in kernel format 773 */ 774 int 775 kern_abort2(struct thread *td, const char *why, int nargs, void **uargs) 776 { 777 struct proc *p = td->td_proc; 778 struct sbuf *sb; 779 int error, i, sig; 780 781 /* 782 * Do it right now so we can log either proper call of abort2(), or 783 * note, that invalid argument was passed. 512 is big enough to 784 * handle 16 arguments' descriptions with additional comments. 785 */ 786 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 787 sbuf_clear(sb); 788 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 789 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 790 /* 791 * Since we can't return from abort2(), send SIGKILL in cases, where 792 * abort2() was called improperly 793 */ 794 sig = SIGKILL; 795 /* Prevent from DoSes from user-space. */ 796 if (nargs == -1) 797 goto out; 798 KASSERT(nargs >= 0 && nargs <= 16, ("called with too many args (%d)", 799 nargs)); 800 /* 801 * Limit size of 'reason' string to 128. Will fit even when 802 * maximal number of arguments was chosen to be logged. 803 */ 804 if (why != NULL) { 805 error = sbuf_copyin(sb, why, 128); 806 if (error < 0) 807 goto out; 808 } else { 809 sbuf_printf(sb, "(null)"); 810 } 811 if (nargs > 0) { 812 sbuf_printf(sb, "("); 813 for (i = 0;i < nargs; i++) 814 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 815 sbuf_printf(sb, ")"); 816 } 817 /* 818 * Final stage: arguments were proper, string has been 819 * successfully copied from userspace, and copying pointers 820 * from user-space succeed. 821 */ 822 sig = SIGABRT; 823 out: 824 if (sig == SIGKILL) { 825 sbuf_trim(sb); 826 sbuf_printf(sb, " (Reason text inaccessible)"); 827 } 828 sbuf_cat(sb, "\n"); 829 sbuf_finish(sb); 830 log(LOG_INFO, "%s", sbuf_data(sb)); 831 sbuf_delete(sb); 832 exit1(td, 0, sig); 833 return (0); 834 } 835 836 #ifdef COMPAT_43 837 /* 838 * The dirty work is handled by kern_wait(). 839 */ 840 int 841 owait(struct thread *td, struct owait_args *uap __unused) 842 { 843 int error, status; 844 845 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 846 if (error == 0) 847 td->td_retval[1] = status; 848 return (error); 849 } 850 #endif /* COMPAT_43 */ 851 852 /* 853 * The dirty work is handled by kern_wait(). 854 */ 855 int 856 sys_wait4(struct thread *td, struct wait4_args *uap) 857 { 858 struct rusage ru, *rup; 859 int error, status; 860 861 if (uap->rusage != NULL) 862 rup = &ru; 863 else 864 rup = NULL; 865 error = kern_wait(td, uap->pid, &status, uap->options, rup); 866 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0) 867 error = copyout(&status, uap->status, sizeof(status)); 868 if (uap->rusage != NULL && error == 0 && td->td_retval[0] != 0) 869 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 870 return (error); 871 } 872 873 int 874 sys_wait6(struct thread *td, struct wait6_args *uap) 875 { 876 struct __wrusage wru, *wrup; 877 siginfo_t si, *sip; 878 idtype_t idtype; 879 id_t id; 880 int error, status; 881 882 idtype = uap->idtype; 883 id = uap->id; 884 885 if (uap->wrusage != NULL) 886 wrup = &wru; 887 else 888 wrup = NULL; 889 890 if (uap->info != NULL) { 891 sip = &si; 892 bzero(sip, sizeof(*sip)); 893 } else 894 sip = NULL; 895 896 /* 897 * We expect all callers of wait6() to know about WEXITED and 898 * WTRAPPED. 899 */ 900 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip); 901 902 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0) 903 error = copyout(&status, uap->status, sizeof(status)); 904 if (uap->wrusage != NULL && error == 0 && td->td_retval[0] != 0) 905 error = copyout(&wru, uap->wrusage, sizeof(wru)); 906 if (uap->info != NULL && error == 0) 907 error = copyout(&si, uap->info, sizeof(si)); 908 return (error); 909 } 910 911 /* 912 * Reap the remains of a zombie process and optionally return status and 913 * rusage. Asserts and will release both the proctree_lock and the process 914 * lock as part of its work. 915 */ 916 void 917 proc_reap(struct thread *td, struct proc *p, int *status, int options) 918 { 919 struct proc *q, *t; 920 921 sx_assert(&proctree_lock, SA_XLOCKED); 922 PROC_LOCK_ASSERT(p, MA_OWNED); 923 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 924 925 mtx_spin_wait_unlocked(&p->p_slock); 926 927 q = td->td_proc; 928 929 if (status) 930 *status = KW_EXITCODE(p->p_xexit, p->p_xsig); 931 if (options & WNOWAIT) { 932 /* 933 * Only poll, returning the status. Caller does not wish to 934 * release the proc struct just yet. 935 */ 936 PROC_UNLOCK(p); 937 sx_xunlock(&proctree_lock); 938 return; 939 } 940 941 PROC_LOCK(q); 942 sigqueue_take(p->p_ksi); 943 PROC_UNLOCK(q); 944 945 /* 946 * If we got the child via a ptrace 'attach', we need to give it back 947 * to the old parent. 948 */ 949 if (p->p_oppid != p->p_pptr->p_pid) { 950 PROC_UNLOCK(p); 951 t = proc_realparent(p); 952 PROC_LOCK(t); 953 PROC_LOCK(p); 954 CTR2(KTR_PTRACE, 955 "wait: traced child %d moved back to parent %d", p->p_pid, 956 t->p_pid); 957 proc_reparent(p, t, false); 958 PROC_UNLOCK(p); 959 pksignal(t, SIGCHLD, p->p_ksi); 960 wakeup(t); 961 cv_broadcast(&p->p_pwait); 962 PROC_UNLOCK(t); 963 sx_xunlock(&proctree_lock); 964 return; 965 } 966 PROC_UNLOCK(p); 967 968 /* 969 * Remove other references to this process to ensure we have an 970 * exclusive reference. 971 */ 972 sx_xlock(PIDHASHLOCK(p->p_pid)); 973 LIST_REMOVE(p, p_hash); 974 sx_xunlock(PIDHASHLOCK(p->p_pid)); 975 LIST_REMOVE(p, p_sibling); 976 reaper_abandon_children(p, true); 977 reaper_clear(p); 978 PROC_LOCK(p); 979 proc_clear_orphan(p); 980 PROC_UNLOCK(p); 981 leavepgrp(p); 982 if (p->p_procdesc != NULL) 983 procdesc_reap(p); 984 sx_xunlock(&proctree_lock); 985 986 proc_id_clear(PROC_ID_PID, p->p_pid); 987 988 PROC_LOCK(p); 989 knlist_detach(p->p_klist); 990 p->p_klist = NULL; 991 PROC_UNLOCK(p); 992 993 /* 994 * Removal from allproc list and process group list paired with 995 * PROC_LOCK which was executed during that time should guarantee 996 * nothing can reach this process anymore. As such further locking 997 * is unnecessary. 998 */ 999 p->p_xexit = p->p_xsig = 0; /* XXX: why? */ 1000 1001 PROC_LOCK(q); 1002 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 1003 PROC_UNLOCK(q); 1004 1005 /* 1006 * Decrement the count of procs running with this uid. 1007 */ 1008 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 1009 1010 /* 1011 * Destroy resource accounting information associated with the process. 1012 */ 1013 #ifdef RACCT 1014 if (racct_enable) { 1015 PROC_LOCK(p); 1016 racct_sub(p, RACCT_NPROC, 1); 1017 PROC_UNLOCK(p); 1018 } 1019 #endif 1020 racct_proc_exit(p); 1021 1022 /* 1023 * Free credentials, arguments, and sigacts. 1024 */ 1025 proc_unset_cred(p); 1026 pargs_drop(p->p_args); 1027 p->p_args = NULL; 1028 sigacts_free(p->p_sigacts); 1029 p->p_sigacts = NULL; 1030 1031 /* 1032 * Do any thread-system specific cleanups. 1033 */ 1034 thread_wait(p); 1035 1036 /* 1037 * Give vm and machine-dependent layer a chance to free anything that 1038 * cpu_exit couldn't release while still running in process context. 1039 */ 1040 vm_waitproc(p); 1041 #ifdef MAC 1042 mac_proc_destroy(p); 1043 #endif 1044 1045 KASSERT(FIRST_THREAD_IN_PROC(p), 1046 ("proc_reap: no residual thread!")); 1047 uma_zfree(proc_zone, p); 1048 atomic_add_int(&nprocs, -1); 1049 } 1050 1051 static int 1052 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id, 1053 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo, 1054 int check_only) 1055 { 1056 struct rusage *rup; 1057 1058 sx_assert(&proctree_lock, SA_XLOCKED); 1059 1060 PROC_LOCK(p); 1061 1062 switch (idtype) { 1063 case P_ALL: 1064 if (p->p_procdesc == NULL || 1065 (p->p_pptr == td->td_proc && 1066 (p->p_flag & P_TRACED) != 0)) { 1067 break; 1068 } 1069 1070 PROC_UNLOCK(p); 1071 return (0); 1072 case P_PID: 1073 if (p->p_pid != (pid_t)id) { 1074 PROC_UNLOCK(p); 1075 return (0); 1076 } 1077 break; 1078 case P_PGID: 1079 if (p->p_pgid != (pid_t)id) { 1080 PROC_UNLOCK(p); 1081 return (0); 1082 } 1083 break; 1084 case P_SID: 1085 if (p->p_session->s_sid != (pid_t)id) { 1086 PROC_UNLOCK(p); 1087 return (0); 1088 } 1089 break; 1090 case P_UID: 1091 if (p->p_ucred->cr_uid != (uid_t)id) { 1092 PROC_UNLOCK(p); 1093 return (0); 1094 } 1095 break; 1096 case P_GID: 1097 if (p->p_ucred->cr_gid != (gid_t)id) { 1098 PROC_UNLOCK(p); 1099 return (0); 1100 } 1101 break; 1102 case P_JAILID: 1103 if (p->p_ucred->cr_prison->pr_id != (int)id) { 1104 PROC_UNLOCK(p); 1105 return (0); 1106 } 1107 break; 1108 /* 1109 * It seems that the thread structures get zeroed out 1110 * at process exit. This makes it impossible to 1111 * support P_SETID, P_CID or P_CPUID. 1112 */ 1113 default: 1114 PROC_UNLOCK(p); 1115 return (0); 1116 } 1117 1118 if (p_canwait(td, p)) { 1119 PROC_UNLOCK(p); 1120 return (0); 1121 } 1122 1123 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) { 1124 PROC_UNLOCK(p); 1125 return (0); 1126 } 1127 1128 /* 1129 * This special case handles a kthread spawned by linux_clone 1130 * (see linux_misc.c). The linux_wait4 and linux_waitpid 1131 * functions need to be able to distinguish between waiting 1132 * on a process and waiting on a thread. It is a thread if 1133 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 1134 * signifies we want to wait for threads and not processes. 1135 */ 1136 if ((p->p_sigparent != SIGCHLD) ^ 1137 ((options & WLINUXCLONE) != 0)) { 1138 PROC_UNLOCK(p); 1139 return (0); 1140 } 1141 1142 if (siginfo != NULL) { 1143 bzero(siginfo, sizeof(*siginfo)); 1144 siginfo->si_errno = 0; 1145 1146 /* 1147 * SUSv4 requires that the si_signo value is always 1148 * SIGCHLD. Obey it despite the rfork(2) interface 1149 * allows to request other signal for child exit 1150 * notification. 1151 */ 1152 siginfo->si_signo = SIGCHLD; 1153 1154 /* 1155 * This is still a rough estimate. We will fix the 1156 * cases TRAPPED, STOPPED, and CONTINUED later. 1157 */ 1158 if (WCOREDUMP(p->p_xsig)) { 1159 siginfo->si_code = CLD_DUMPED; 1160 siginfo->si_status = WTERMSIG(p->p_xsig); 1161 } else if (WIFSIGNALED(p->p_xsig)) { 1162 siginfo->si_code = CLD_KILLED; 1163 siginfo->si_status = WTERMSIG(p->p_xsig); 1164 } else { 1165 siginfo->si_code = CLD_EXITED; 1166 siginfo->si_status = p->p_xexit; 1167 } 1168 1169 siginfo->si_pid = p->p_pid; 1170 siginfo->si_uid = p->p_ucred->cr_uid; 1171 1172 /* 1173 * The si_addr field would be useful additional 1174 * detail, but apparently the PC value may be lost 1175 * when we reach this point. bzero() above sets 1176 * siginfo->si_addr to NULL. 1177 */ 1178 } 1179 1180 /* 1181 * There should be no reason to limit resources usage info to 1182 * exited processes only. A snapshot about any resources used 1183 * by a stopped process may be exactly what is needed. 1184 */ 1185 if (wrusage != NULL) { 1186 rup = &wrusage->wru_self; 1187 *rup = p->p_ru; 1188 PROC_STATLOCK(p); 1189 calcru(p, &rup->ru_utime, &rup->ru_stime); 1190 PROC_STATUNLOCK(p); 1191 1192 rup = &wrusage->wru_children; 1193 *rup = p->p_stats->p_cru; 1194 calccru(p, &rup->ru_utime, &rup->ru_stime); 1195 } 1196 1197 if (p->p_state == PRS_ZOMBIE && !check_only) { 1198 proc_reap(td, p, status, options); 1199 return (-1); 1200 } 1201 return (1); 1202 } 1203 1204 int 1205 kern_wait(struct thread *td, pid_t pid, int *status, int options, 1206 struct rusage *rusage) 1207 { 1208 struct __wrusage wru, *wrup; 1209 idtype_t idtype; 1210 id_t id; 1211 int ret; 1212 1213 /* 1214 * Translate the special pid values into the (idtype, pid) 1215 * pair for kern_wait6. The WAIT_MYPGRP case is handled by 1216 * kern_wait6() on its own. 1217 */ 1218 if (pid == WAIT_ANY) { 1219 idtype = P_ALL; 1220 id = 0; 1221 } else if (pid < 0) { 1222 idtype = P_PGID; 1223 id = (id_t)-pid; 1224 } else { 1225 idtype = P_PID; 1226 id = (id_t)pid; 1227 } 1228 1229 if (rusage != NULL) 1230 wrup = &wru; 1231 else 1232 wrup = NULL; 1233 1234 /* 1235 * For backward compatibility we implicitly add flags WEXITED 1236 * and WTRAPPED here. 1237 */ 1238 options |= WEXITED | WTRAPPED; 1239 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL); 1240 if (rusage != NULL) 1241 *rusage = wru.wru_self; 1242 return (ret); 1243 } 1244 1245 static void 1246 report_alive_proc(struct thread *td, struct proc *p, siginfo_t *siginfo, 1247 int *status, int options, int si_code) 1248 { 1249 bool cont; 1250 1251 PROC_LOCK_ASSERT(p, MA_OWNED); 1252 sx_assert(&proctree_lock, SA_XLOCKED); 1253 MPASS(si_code == CLD_TRAPPED || si_code == CLD_STOPPED || 1254 si_code == CLD_CONTINUED); 1255 1256 cont = si_code == CLD_CONTINUED; 1257 if ((options & WNOWAIT) == 0) { 1258 if (cont) 1259 p->p_flag &= ~P_CONTINUED; 1260 else 1261 p->p_flag |= P_WAITED; 1262 if (kern_wait_dequeue_sigchld && 1263 (td->td_proc->p_sysent->sv_flags & SV_SIG_WAITNDQ) == 0) { 1264 PROC_LOCK(td->td_proc); 1265 sigqueue_take(p->p_ksi); 1266 PROC_UNLOCK(td->td_proc); 1267 } 1268 } 1269 sx_xunlock(&proctree_lock); 1270 if (siginfo != NULL) { 1271 siginfo->si_code = si_code; 1272 siginfo->si_status = cont ? SIGCONT : p->p_xsig; 1273 } 1274 if (status != NULL) 1275 *status = cont ? SIGCONT : W_STOPCODE(p->p_xsig); 1276 td->td_retval[0] = p->p_pid; 1277 PROC_UNLOCK(p); 1278 } 1279 1280 int 1281 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status, 1282 int options, struct __wrusage *wrusage, siginfo_t *siginfo) 1283 { 1284 struct proc *p, *q; 1285 pid_t pid; 1286 int error, nfound, ret; 1287 bool report; 1288 1289 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */ 1290 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */ 1291 AUDIT_ARG_VALUE(options); 1292 1293 q = td->td_proc; 1294 1295 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { 1296 PROC_LOCK(q); 1297 id = (id_t)q->p_pgid; 1298 PROC_UNLOCK(q); 1299 idtype = P_PGID; 1300 } 1301 1302 /* If we don't know the option, just return. */ 1303 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT | 1304 WEXITED | WTRAPPED | WLINUXCLONE)) != 0) 1305 return (EINVAL); 1306 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) { 1307 /* 1308 * We will be unable to find any matching processes, 1309 * because there are no known events to look for. 1310 * Prefer to return error instead of blocking 1311 * indefinitely. 1312 */ 1313 return (EINVAL); 1314 } 1315 1316 loop: 1317 if (q->p_flag & P_STATCHILD) { 1318 PROC_LOCK(q); 1319 q->p_flag &= ~P_STATCHILD; 1320 PROC_UNLOCK(q); 1321 } 1322 sx_xlock(&proctree_lock); 1323 loop_locked: 1324 nfound = 0; 1325 LIST_FOREACH(p, &q->p_children, p_sibling) { 1326 pid = p->p_pid; 1327 ret = proc_to_reap(td, p, idtype, id, status, options, 1328 wrusage, siginfo, 0); 1329 if (ret == 0) 1330 continue; 1331 else if (ret != 1) { 1332 td->td_retval[0] = pid; 1333 return (0); 1334 } 1335 1336 nfound++; 1337 PROC_LOCK_ASSERT(p, MA_OWNED); 1338 1339 if ((options & WTRAPPED) != 0 && 1340 (p->p_flag & P_TRACED) != 0) { 1341 PROC_SLOCK(p); 1342 report = 1343 ((p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) && 1344 p->p_suspcount == p->p_numthreads && 1345 (p->p_flag & P_WAITED) == 0); 1346 PROC_SUNLOCK(p); 1347 if (report) { 1348 CTR4(KTR_PTRACE, 1349 "wait: returning trapped pid %d status %#x " 1350 "(xstat %d) xthread %d", 1351 p->p_pid, W_STOPCODE(p->p_xsig), p->p_xsig, 1352 p->p_xthread != NULL ? 1353 p->p_xthread->td_tid : -1); 1354 report_alive_proc(td, p, siginfo, status, 1355 options, CLD_TRAPPED); 1356 return (0); 1357 } 1358 } 1359 if ((options & WUNTRACED) != 0 && 1360 (p->p_flag & P_STOPPED_SIG) != 0) { 1361 PROC_SLOCK(p); 1362 report = (p->p_suspcount == p->p_numthreads && 1363 ((p->p_flag & P_WAITED) == 0)); 1364 PROC_SUNLOCK(p); 1365 if (report) { 1366 report_alive_proc(td, p, siginfo, status, 1367 options, CLD_STOPPED); 1368 return (0); 1369 } 1370 } 1371 if ((options & WCONTINUED) != 0 && 1372 (p->p_flag & P_CONTINUED) != 0) { 1373 report_alive_proc(td, p, siginfo, status, options, 1374 CLD_CONTINUED); 1375 return (0); 1376 } 1377 PROC_UNLOCK(p); 1378 } 1379 1380 /* 1381 * Look in the orphans list too, to allow the parent to 1382 * collect it's child exit status even if child is being 1383 * debugged. 1384 * 1385 * Debugger detaches from the parent upon successful 1386 * switch-over from parent to child. At this point due to 1387 * re-parenting the parent loses the child to debugger and a 1388 * wait4(2) call would report that it has no children to wait 1389 * for. By maintaining a list of orphans we allow the parent 1390 * to successfully wait until the child becomes a zombie. 1391 */ 1392 if (nfound == 0) { 1393 LIST_FOREACH(p, &q->p_orphans, p_orphan) { 1394 ret = proc_to_reap(td, p, idtype, id, NULL, options, 1395 NULL, NULL, 1); 1396 if (ret != 0) { 1397 KASSERT(ret != -1, ("reaped an orphan (pid %d)", 1398 (int)td->td_retval[0])); 1399 PROC_UNLOCK(p); 1400 nfound++; 1401 break; 1402 } 1403 } 1404 } 1405 if (nfound == 0) { 1406 sx_xunlock(&proctree_lock); 1407 return (ECHILD); 1408 } 1409 if (options & WNOHANG) { 1410 sx_xunlock(&proctree_lock); 1411 td->td_retval[0] = 0; 1412 return (0); 1413 } 1414 PROC_LOCK(q); 1415 if (q->p_flag & P_STATCHILD) { 1416 q->p_flag &= ~P_STATCHILD; 1417 PROC_UNLOCK(q); 1418 goto loop_locked; 1419 } 1420 sx_xunlock(&proctree_lock); 1421 error = msleep(q, &q->p_mtx, PWAIT | PCATCH | PDROP, "wait", 0); 1422 if (error) 1423 return (error); 1424 goto loop; 1425 } 1426 1427 void 1428 proc_add_orphan(struct proc *child, struct proc *parent) 1429 { 1430 1431 sx_assert(&proctree_lock, SX_XLOCKED); 1432 KASSERT((child->p_flag & P_TRACED) != 0, 1433 ("proc_add_orphan: not traced")); 1434 1435 if (LIST_EMPTY(&parent->p_orphans)) { 1436 child->p_treeflag |= P_TREE_FIRST_ORPHAN; 1437 LIST_INSERT_HEAD(&parent->p_orphans, child, p_orphan); 1438 } else { 1439 LIST_INSERT_AFTER(LIST_FIRST(&parent->p_orphans), 1440 child, p_orphan); 1441 } 1442 child->p_treeflag |= P_TREE_ORPHANED; 1443 } 1444 1445 /* 1446 * Make process 'parent' the new parent of process 'child'. 1447 * Must be called with an exclusive hold of proctree lock. 1448 */ 1449 void 1450 proc_reparent(struct proc *child, struct proc *parent, bool set_oppid) 1451 { 1452 1453 sx_assert(&proctree_lock, SX_XLOCKED); 1454 PROC_LOCK_ASSERT(child, MA_OWNED); 1455 if (child->p_pptr == parent) 1456 return; 1457 1458 PROC_LOCK(child->p_pptr); 1459 sigqueue_take(child->p_ksi); 1460 PROC_UNLOCK(child->p_pptr); 1461 LIST_REMOVE(child, p_sibling); 1462 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1463 1464 proc_clear_orphan(child); 1465 if ((child->p_flag & P_TRACED) != 0) { 1466 proc_add_orphan(child, child->p_pptr); 1467 } 1468 1469 child->p_pptr = parent; 1470 if (set_oppid) 1471 child->p_oppid = parent->p_pid; 1472 } 1473