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 void 224 exit1(struct thread *td, int rval, int signo) 225 { 226 exit2(td, rval, signo, false); 227 } 228 229 /* 230 * Exit: deallocate address space and other resources, change proc state to 231 * zombie, and unlink proc from allproc and parent's lists. Save exit status 232 * and rusage for wait(). Check for child processes and orphan them. 233 */ 234 void 235 exit2(struct thread *td, int rval, int signo, bool dec_killpg_cnt) 236 { 237 struct proc *p, *nq, *q, *t; 238 struct thread *tdt; 239 ksiginfo_t *ksi, *ksi1; 240 int signal_parent; 241 242 mtx_assert(&Giant, MA_NOTOWNED); 243 KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo)); 244 TSPROCEXIT(td->td_proc->p_pid); 245 246 p = td->td_proc; 247 /* 248 * XXX in case we're rebooting we just let init die in order to 249 * work around an unsolved stack overflow seen very late during 250 * shutdown on sparc64 when the gmirror worker process exists. 251 * XXX what to do now that sparc64 is gone... remove if? 252 */ 253 if (p == initproc && rebooting == 0) { 254 printf("init died (signal %d, exit %d)\n", signo, rval); 255 panic("Going nowhere without my init!"); 256 } 257 258 /* 259 * Process deferred operations, designated with ASTF_KCLEAR. 260 * For instance, we need to deref SU mp, since the thread does 261 * not return to userspace, and wait for geom to stabilize. 262 */ 263 ast_kclear(td); 264 265 /* 266 * MUST abort all other threads before proceeding past here. 267 */ 268 PROC_LOCK(p); 269 proc_set_p2_wexit(p); 270 271 /* 272 * First check if some other thread or external request got 273 * here before us. If so, act appropriately: exit or suspend. 274 * We must ensure that stop requests are handled before we set 275 * P_WEXIT. 276 */ 277 thread_suspend_check(0); 278 while (p->p_flag & P_HADTHREADS) { 279 /* 280 * Kill off the other threads. This requires 281 * some co-operation from other parts of the kernel 282 * so it may not be instantaneous. With this state set 283 * any thread attempting to interruptibly 284 * sleep will return immediately with EINTR or EWOULDBLOCK 285 * which will hopefully force them to back out to userland 286 * freeing resources as they go. Any thread attempting 287 * to return to userland will thread_exit() from ast(). 288 * thread_exit() will unsuspend us when the last of the 289 * other threads exits. 290 * If there is already a thread singler after resumption, 291 * calling thread_single() will fail; in that case, we just 292 * re-check all suspension request, the thread should 293 * either be suspended there or exit. 294 */ 295 if (!thread_single(p, SINGLE_EXIT)) 296 /* 297 * All other activity in this process is now 298 * stopped. Threading support has been turned 299 * off. 300 */ 301 break; 302 /* 303 * Recheck for new stop or suspend requests which 304 * might appear while process lock was dropped in 305 * thread_single(). 306 */ 307 thread_suspend_check(0); 308 } 309 KASSERT(p->p_numthreads == 1, 310 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 311 racct_sub(p, RACCT_NTHR, 1); 312 313 if (dec_killpg_cnt) { 314 MPASS(atomic_load_int(&p->p_killpg_cnt) > 0); 315 atomic_add_int(&p->p_killpg_cnt, -1); 316 } 317 318 /* Let event handler change exit status */ 319 p->p_xexit = rval; 320 p->p_xsig = signo; 321 322 /* 323 * Ignore any pending request to stop due to a stop signal. 324 * Once P_WEXIT is set, future requests will be ignored as 325 * well. 326 */ 327 p->p_flag &= ~P_STOPPED_SIG; 328 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped")); 329 330 /* Note that we are exiting. */ 331 p->p_flag |= P_WEXIT; 332 333 /* 334 * Wait for any processes that have a hold on our vmspace to 335 * release their reference. 336 */ 337 while (p->p_lock > 0) 338 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 339 340 PROC_UNLOCK(p); 341 /* Drain the limit callout while we don't have the proc locked */ 342 callout_drain(&p->p_limco); 343 344 #ifdef AUDIT 345 /* 346 * The Sun BSM exit token contains two components: an exit status as 347 * passed to exit(), and a return value to indicate what sort of exit 348 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 349 * what the return value is. 350 */ 351 AUDIT_ARG_EXIT(rval, 0); 352 AUDIT_SYSCALL_EXIT(0, td); 353 #endif 354 355 /* Are we a task leader with peers? */ 356 if (p->p_peers != NULL && p == p->p_leader) { 357 mtx_lock(&ppeers_lock); 358 q = p->p_peers; 359 while (q != NULL) { 360 PROC_LOCK(q); 361 kern_psignal(q, SIGKILL); 362 PROC_UNLOCK(q); 363 q = q->p_peers; 364 } 365 while (p->p_peers != NULL) 366 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 367 mtx_unlock(&ppeers_lock); 368 } 369 370 itimers_exit(p); 371 372 /* 373 * Check if any loadable modules need anything done at process exit. 374 * E.g. SYSV IPC stuff. 375 * Event handler could change exit status. 376 * XXX what if one of these generates an error? 377 */ 378 EVENTHANDLER_DIRECT_INVOKE(process_exit, p); 379 380 /* 381 * If parent is waiting for us to exit or exec, 382 * P_PPWAIT is set; we will wakeup the parent below. 383 */ 384 PROC_LOCK(p); 385 stopprofclock(p); 386 p->p_ptevents = 0; 387 388 /* 389 * Stop the real interval timer. If the handler is currently 390 * executing, prevent it from rearming itself and let it finish. 391 */ 392 if (timevalisset(&p->p_realtimer.it_value) && 393 callout_stop(&p->p_itcallout) == 0) { 394 timevalclear(&p->p_realtimer.it_interval); 395 PROC_UNLOCK(p); 396 callout_drain(&p->p_itcallout); 397 } else { 398 PROC_UNLOCK(p); 399 } 400 401 if (p->p_sysent->sv_onexit != NULL) 402 p->p_sysent->sv_onexit(p); 403 seltdfini(td); 404 405 /* 406 * Reset any sigio structures pointing to us as a result of 407 * F_SETOWN with our pid. The P_WEXIT flag interlocks with fsetown(). 408 */ 409 funsetownlst(&p->p_sigiolst); 410 411 /* 412 * Close open files and release open-file table. 413 * This may block! 414 */ 415 pdescfree(td); 416 fdescfree(td); 417 418 /* 419 * Remove ourself from our leader's peer list and wake our leader. 420 */ 421 if (p->p_leader->p_peers != NULL) { 422 mtx_lock(&ppeers_lock); 423 if (p->p_leader->p_peers != NULL) { 424 q = p->p_leader; 425 while (q->p_peers != p) 426 q = q->p_peers; 427 q->p_peers = p->p_peers; 428 wakeup(p->p_leader); 429 } 430 mtx_unlock(&ppeers_lock); 431 } 432 433 exec_free_abi_mappings(p); 434 vmspace_exit(td); 435 (void)acct_process(td); 436 437 #ifdef KTRACE 438 ktrprocexit(td); 439 #endif 440 /* 441 * Release reference to text vnode etc 442 */ 443 if (p->p_textvp != NULL) { 444 vrele(p->p_textvp); 445 p->p_textvp = NULL; 446 } 447 if (p->p_textdvp != NULL) { 448 vrele(p->p_textdvp); 449 p->p_textdvp = NULL; 450 } 451 if (p->p_binname != NULL) { 452 free(p->p_binname, M_PARGS); 453 p->p_binname = NULL; 454 } 455 456 /* 457 * Release our limits structure. 458 */ 459 lim_free(p->p_limit); 460 p->p_limit = NULL; 461 462 tidhash_remove(td); 463 464 /* 465 * Call machine-dependent code to release any 466 * machine-dependent resources other than the address space. 467 * The address space is released by "vmspace_exitfree(p)" in 468 * vm_waitproc(). 469 */ 470 cpu_exit(td); 471 472 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 473 474 /* 475 * Remove from allproc. It still sits in the hash. 476 */ 477 sx_xlock(&allproc_lock); 478 LIST_REMOVE(p, p_list); 479 480 #ifdef DDB 481 /* 482 * Used by ddb's 'ps' command to find this process via the 483 * pidhash. 484 */ 485 p->p_list.le_prev = NULL; 486 #endif 487 prison_proc_unlink(p->p_ucred->cr_prison, p); 488 sx_xunlock(&allproc_lock); 489 490 sx_xlock(&proctree_lock); 491 if ((p->p_flag & (P_TRACED | P_PPWAIT | P_PPTRACE)) != 0) { 492 PROC_LOCK(p); 493 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE); 494 PROC_UNLOCK(p); 495 } 496 497 /* 498 * killjobc() might drop and re-acquire proctree_lock to 499 * revoke control tty if exiting process was a session leader. 500 */ 501 killjobc(); 502 503 /* 504 * Reparent all children processes: 505 * - traced ones to the original parent (or init if we are that parent) 506 * - the rest to init 507 */ 508 q = LIST_FIRST(&p->p_children); 509 if (q != NULL) /* only need this if any child is S_ZOMB */ 510 wakeup(q->p_reaper); 511 for (; q != NULL; q = nq) { 512 nq = LIST_NEXT(q, p_sibling); 513 ksi = ksiginfo_alloc(M_WAITOK); 514 PROC_LOCK(q); 515 q->p_sigparent = SIGCHLD; 516 517 if ((q->p_flag & P_TRACED) == 0) { 518 proc_reparent(q, q->p_reaper, true); 519 if (q->p_state == PRS_ZOMBIE) { 520 /* 521 * Inform reaper about the reparented 522 * zombie, since wait(2) has something 523 * new to report. Guarantee queueing 524 * of the SIGCHLD signal, similar to 525 * the _exit() behaviour, by providing 526 * our ksiginfo. Ksi is freed by the 527 * signal delivery. 528 */ 529 if (q->p_ksi == NULL) { 530 ksi1 = NULL; 531 } else { 532 ksiginfo_copy(q->p_ksi, ksi); 533 ksi->ksi_flags |= KSI_INS; 534 ksi1 = ksi; 535 ksi = NULL; 536 } 537 PROC_LOCK(q->p_reaper); 538 pksignal(q->p_reaper, SIGCHLD, ksi1); 539 PROC_UNLOCK(q->p_reaper); 540 } else if (q->p_pdeathsig > 0) { 541 /* 542 * The child asked to received a signal 543 * when we exit. 544 */ 545 kern_psignal(q, q->p_pdeathsig); 546 } 547 } else { 548 /* 549 * Traced processes are killed by default 550 * since their existence means someone is 551 * screwing up. 552 */ 553 t = proc_realparent(q); 554 if (t == p) { 555 proc_reparent(q, q->p_reaper, true); 556 } else { 557 PROC_LOCK(t); 558 proc_reparent(q, t, true); 559 PROC_UNLOCK(t); 560 } 561 /* 562 * Since q was found on our children list, the 563 * proc_reparent() call moved q to the orphan 564 * list due to present P_TRACED flag. Clear 565 * orphan link for q now while q is locked. 566 */ 567 proc_clear_orphan(q); 568 q->p_flag &= ~P_TRACED; 569 q->p_flag2 &= ~P2_PTRACE_FSTP; 570 q->p_ptevents = 0; 571 p->p_xthread = NULL; 572 FOREACH_THREAD_IN_PROC(q, tdt) { 573 tdt->td_dbgflags &= ~(TDB_SUSPEND | TDB_XSIG | 574 TDB_FSTP); 575 tdt->td_xsig = 0; 576 } 577 if (kern_kill_on_dbg_exit) { 578 q->p_flag &= ~P_STOPPED_TRACE; 579 kern_psignal(q, SIGKILL); 580 } else if ((q->p_flag & (P_STOPPED_TRACE | 581 P_STOPPED_SIG)) != 0) { 582 sigqueue_delete_proc(q, SIGTRAP); 583 ptrace_unsuspend(q); 584 } 585 } 586 PROC_UNLOCK(q); 587 if (ksi != NULL) 588 ksiginfo_free(ksi); 589 } 590 591 /* 592 * Also get rid of our orphans. 593 */ 594 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) { 595 PROC_LOCK(q); 596 KASSERT(q->p_oppid == p->p_pid, 597 ("orphan %p of %p has unexpected oppid %d", q, p, 598 q->p_oppid)); 599 q->p_oppid = q->p_reaper->p_pid; 600 601 /* 602 * If we are the real parent of this process 603 * but it has been reparented to a debugger, then 604 * check if it asked for a signal when we exit. 605 */ 606 if (q->p_pdeathsig > 0) 607 kern_psignal(q, q->p_pdeathsig); 608 CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid, 609 q->p_pid); 610 proc_clear_orphan(q); 611 PROC_UNLOCK(q); 612 } 613 614 #ifdef KDTRACE_HOOKS 615 if (SDT_PROBES_ENABLED()) { 616 int reason = CLD_EXITED; 617 if (WCOREDUMP(signo)) 618 reason = CLD_DUMPED; 619 else if (WIFSIGNALED(signo)) 620 reason = CLD_KILLED; 621 SDT_PROBE1(proc, , , exit, reason); 622 } 623 #endif 624 625 /* Save exit status. */ 626 PROC_LOCK(p); 627 p->p_xthread = td; 628 629 if (p->p_sysent->sv_ontdexit != NULL) 630 p->p_sysent->sv_ontdexit(td); 631 632 #ifdef KDTRACE_HOOKS 633 /* 634 * Tell the DTrace fasttrap provider about the exit if it 635 * has declared an interest. 636 */ 637 if (dtrace_fasttrap_exit) 638 dtrace_fasttrap_exit(p); 639 #endif 640 641 /* 642 * Notify interested parties of our demise. 643 */ 644 KNOTE_LOCKED(p->p_klist, NOTE_EXIT); 645 646 /* 647 * If this is a process with a descriptor, we may not need to deliver 648 * a signal to the parent. proctree_lock is held over 649 * procdesc_exit() to serialize concurrent calls to close() and 650 * exit(). 651 */ 652 signal_parent = 0; 653 if (p->p_procdesc == NULL || procdesc_exit(p)) { 654 /* 655 * Notify parent that we're gone. If parent has the 656 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN, 657 * notify process 1 instead (and hope it will handle this 658 * situation). 659 */ 660 PROC_LOCK(p->p_pptr); 661 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 662 if (p->p_pptr->p_sigacts->ps_flag & 663 (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 664 struct proc *pp; 665 666 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 667 pp = p->p_pptr; 668 PROC_UNLOCK(pp); 669 proc_reparent(p, p->p_reaper, true); 670 p->p_sigparent = SIGCHLD; 671 PROC_LOCK(p->p_pptr); 672 673 /* 674 * Notify parent, so in case he was wait(2)ing or 675 * executing waitpid(2) with our pid, he will 676 * continue. 677 */ 678 wakeup(pp); 679 } else 680 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 681 682 if (p->p_pptr == p->p_reaper || p->p_pptr == initproc) { 683 signal_parent = 1; 684 } else if (p->p_sigparent != 0) { 685 if (p->p_sigparent == SIGCHLD) { 686 signal_parent = 1; 687 } else { /* LINUX thread */ 688 signal_parent = 2; 689 } 690 } 691 } else 692 PROC_LOCK(p->p_pptr); 693 sx_xunlock(&proctree_lock); 694 695 if (signal_parent == 1) { 696 childproc_exited(p); 697 } else if (signal_parent == 2) { 698 kern_psignal(p->p_pptr, p->p_sigparent); 699 } 700 701 /* Tell the prison that we are gone. */ 702 prison_proc_free(p->p_ucred->cr_prison); 703 704 /* 705 * The state PRS_ZOMBIE prevents other proesses from sending 706 * signal to the process, to avoid memory leak, we free memory 707 * for signal queue at the time when the state is set. 708 */ 709 sigqueue_flush(&p->p_sigqueue); 710 sigqueue_flush(&td->td_sigqueue); 711 712 /* 713 * We have to wait until after acquiring all locks before 714 * changing p_state. We need to avoid all possible context 715 * switches (including ones from blocking on a mutex) while 716 * marked as a zombie. We also have to set the zombie state 717 * before we release the parent process' proc lock to avoid 718 * a lost wakeup. So, we first call wakeup, then we grab the 719 * sched lock, update the state, and release the parent process' 720 * proc lock. 721 */ 722 wakeup(p->p_pptr); 723 cv_broadcast(&p->p_pwait); 724 sched_exit(p->p_pptr, td); 725 PROC_SLOCK(p); 726 p->p_state = PRS_ZOMBIE; 727 PROC_UNLOCK(p->p_pptr); 728 729 /* 730 * Save our children's rusage information in our exit rusage. 731 */ 732 PROC_STATLOCK(p); 733 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 734 PROC_STATUNLOCK(p); 735 736 /* 737 * Make sure the scheduler takes this thread out of its tables etc. 738 * This will also release this thread's reference to the ucred. 739 * Other thread parts to release include pcb bits and such. 740 */ 741 thread_exit(); 742 } 743 744 #ifndef _SYS_SYSPROTO_H_ 745 struct abort2_args { 746 char *why; 747 int nargs; 748 void **args; 749 }; 750 #endif 751 752 int 753 sys_abort2(struct thread *td, struct abort2_args *uap) 754 { 755 void *uargs[16]; 756 void **uargsp; 757 int error, nargs; 758 759 nargs = uap->nargs; 760 if (nargs < 0 || nargs > nitems(uargs)) 761 nargs = -1; 762 uargsp = NULL; 763 if (nargs > 0) { 764 if (uap->args != NULL) { 765 error = copyin(uap->args, uargs, 766 nargs * sizeof(void *)); 767 if (error != 0) 768 nargs = -1; 769 else 770 uargsp = uargs; 771 } else 772 nargs = -1; 773 } 774 return (kern_abort2(td, uap->why, nargs, uargsp)); 775 } 776 777 /* 778 * kern_abort2() 779 * Arguments: 780 * why - user pointer to why 781 * nargs - number of arguments copied or -1 if an error occurred in copying 782 * args - pointer to an array of pointers in kernel format 783 */ 784 int 785 kern_abort2(struct thread *td, const char *why, int nargs, void **uargs) 786 { 787 struct proc *p = td->td_proc; 788 struct sbuf *sb; 789 int error, i, sig; 790 791 /* 792 * Do it right now so we can log either proper call of abort2(), or 793 * note, that invalid argument was passed. 512 is big enough to 794 * handle 16 arguments' descriptions with additional comments. 795 */ 796 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 797 sbuf_clear(sb); 798 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 799 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 800 /* 801 * Since we can't return from abort2(), send SIGKILL in cases, where 802 * abort2() was called improperly 803 */ 804 sig = SIGKILL; 805 /* Prevent from DoSes from user-space. */ 806 if (nargs == -1) 807 goto out; 808 KASSERT(nargs >= 0 && nargs <= 16, ("called with too many args (%d)", 809 nargs)); 810 /* 811 * Limit size of 'reason' string to 128. Will fit even when 812 * maximal number of arguments was chosen to be logged. 813 */ 814 if (why != NULL) { 815 error = sbuf_copyin(sb, why, 128); 816 if (error < 0) 817 goto out; 818 } else { 819 sbuf_printf(sb, "(null)"); 820 } 821 if (nargs > 0) { 822 sbuf_printf(sb, "("); 823 for (i = 0;i < nargs; i++) 824 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 825 sbuf_printf(sb, ")"); 826 } 827 /* 828 * Final stage: arguments were proper, string has been 829 * successfully copied from userspace, and copying pointers 830 * from user-space succeed. 831 */ 832 sig = SIGABRT; 833 out: 834 if (sig == SIGKILL) { 835 sbuf_trim(sb); 836 sbuf_printf(sb, " (Reason text inaccessible)"); 837 } 838 sbuf_cat(sb, "\n"); 839 sbuf_finish(sb); 840 log(LOG_INFO, "%s", sbuf_data(sb)); 841 sbuf_delete(sb); 842 exit1(td, 0, sig); 843 return (0); 844 } 845 846 #ifdef COMPAT_43 847 /* 848 * The dirty work is handled by kern_wait(). 849 */ 850 int 851 owait(struct thread *td, struct owait_args *uap __unused) 852 { 853 int error, status; 854 855 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 856 if (error == 0) 857 td->td_retval[1] = status; 858 return (error); 859 } 860 #endif /* COMPAT_43 */ 861 862 /* 863 * The dirty work is handled by kern_wait(). 864 */ 865 int 866 sys_wait4(struct thread *td, struct wait4_args *uap) 867 { 868 struct rusage ru, *rup; 869 int error, status; 870 871 if (uap->rusage != NULL) 872 rup = &ru; 873 else 874 rup = NULL; 875 error = kern_wait(td, uap->pid, &status, uap->options, rup); 876 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0) 877 error = copyout(&status, uap->status, sizeof(status)); 878 if (uap->rusage != NULL && error == 0 && td->td_retval[0] != 0) 879 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 880 return (error); 881 } 882 883 int 884 sys_wait6(struct thread *td, struct wait6_args *uap) 885 { 886 struct __wrusage wru, *wrup; 887 siginfo_t si, *sip; 888 idtype_t idtype; 889 id_t id; 890 int error, status; 891 892 idtype = uap->idtype; 893 id = uap->id; 894 895 if (uap->wrusage != NULL) 896 wrup = &wru; 897 else 898 wrup = NULL; 899 900 if (uap->info != NULL) { 901 sip = &si; 902 bzero(sip, sizeof(*sip)); 903 } else 904 sip = NULL; 905 906 /* 907 * We expect all callers of wait6() to know about WEXITED and 908 * WTRAPPED. 909 */ 910 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip); 911 912 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0) 913 error = copyout(&status, uap->status, sizeof(status)); 914 if (uap->wrusage != NULL && error == 0 && td->td_retval[0] != 0) 915 error = copyout(&wru, uap->wrusage, sizeof(wru)); 916 if (uap->info != NULL && error == 0) 917 error = copyout(&si, uap->info, sizeof(si)); 918 return (error); 919 } 920 921 /* 922 * Reap the remains of a zombie process and optionally return status and 923 * rusage. Asserts and will release both the proctree_lock and the process 924 * lock as part of its work. 925 */ 926 void 927 proc_reap(struct thread *td, struct proc *p, int *status, int options) 928 { 929 struct proc *q, *t; 930 931 sx_assert(&proctree_lock, SA_XLOCKED); 932 PROC_LOCK_ASSERT(p, MA_OWNED); 933 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 934 935 mtx_spin_wait_unlocked(&p->p_slock); 936 937 q = td->td_proc; 938 939 if (status) 940 *status = KW_EXITCODE(p->p_xexit, p->p_xsig); 941 if (options & WNOWAIT) { 942 /* 943 * Only poll, returning the status. Caller does not wish to 944 * release the proc struct just yet. 945 */ 946 PROC_UNLOCK(p); 947 sx_xunlock(&proctree_lock); 948 return; 949 } 950 951 PROC_LOCK(q); 952 sigqueue_take(p->p_ksi); 953 PROC_UNLOCK(q); 954 955 /* 956 * If we got the child via a ptrace 'attach', we need to give it back 957 * to the old parent. 958 */ 959 if (p->p_oppid != p->p_pptr->p_pid) { 960 PROC_UNLOCK(p); 961 t = proc_realparent(p); 962 PROC_LOCK(t); 963 PROC_LOCK(p); 964 CTR2(KTR_PTRACE, 965 "wait: traced child %d moved back to parent %d", p->p_pid, 966 t->p_pid); 967 proc_reparent(p, t, false); 968 PROC_UNLOCK(p); 969 pksignal(t, SIGCHLD, p->p_ksi); 970 wakeup(t); 971 cv_broadcast(&p->p_pwait); 972 PROC_UNLOCK(t); 973 sx_xunlock(&proctree_lock); 974 return; 975 } 976 PROC_UNLOCK(p); 977 978 /* 979 * Remove other references to this process to ensure we have an 980 * exclusive reference. 981 */ 982 sx_xlock(PIDHASHLOCK(p->p_pid)); 983 LIST_REMOVE(p, p_hash); 984 sx_xunlock(PIDHASHLOCK(p->p_pid)); 985 LIST_REMOVE(p, p_sibling); 986 reaper_abandon_children(p, true); 987 reaper_clear(p); 988 PROC_LOCK(p); 989 proc_clear_orphan(p); 990 PROC_UNLOCK(p); 991 leavepgrp(p); 992 if (p->p_procdesc != NULL) 993 procdesc_reap(p); 994 sx_xunlock(&proctree_lock); 995 996 proc_id_clear(PROC_ID_PID, p->p_pid); 997 998 PROC_LOCK(p); 999 knlist_detach(p->p_klist); 1000 p->p_klist = NULL; 1001 PROC_UNLOCK(p); 1002 1003 /* 1004 * Removal from allproc list and process group list paired with 1005 * PROC_LOCK which was executed during that time should guarantee 1006 * nothing can reach this process anymore. As such further locking 1007 * is unnecessary. 1008 */ 1009 p->p_xexit = p->p_xsig = 0; /* XXX: why? */ 1010 1011 PROC_LOCK(q); 1012 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 1013 PROC_UNLOCK(q); 1014 1015 /* 1016 * Decrement the count of procs running with this uid. 1017 */ 1018 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 1019 1020 /* 1021 * Destroy resource accounting information associated with the process. 1022 */ 1023 #ifdef RACCT 1024 if (racct_enable) { 1025 PROC_LOCK(p); 1026 racct_sub(p, RACCT_NPROC, 1); 1027 PROC_UNLOCK(p); 1028 } 1029 #endif 1030 racct_proc_exit(p); 1031 1032 /* 1033 * Free credentials, arguments, and sigacts. 1034 */ 1035 proc_unset_cred(p); 1036 pargs_drop(p->p_args); 1037 p->p_args = NULL; 1038 sigacts_free(p->p_sigacts); 1039 p->p_sigacts = NULL; 1040 1041 /* 1042 * Do any thread-system specific cleanups. 1043 */ 1044 thread_wait(p); 1045 1046 /* 1047 * Give vm and machine-dependent layer a chance to free anything that 1048 * cpu_exit couldn't release while still running in process context. 1049 */ 1050 vm_waitproc(p); 1051 #ifdef MAC 1052 mac_proc_destroy(p); 1053 #endif 1054 1055 KASSERT(FIRST_THREAD_IN_PROC(p), 1056 ("proc_reap: no residual thread!")); 1057 uma_zfree(proc_zone, p); 1058 atomic_add_int(&nprocs, -1); 1059 } 1060 1061 static int 1062 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id, 1063 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo, 1064 int check_only) 1065 { 1066 struct rusage *rup; 1067 1068 sx_assert(&proctree_lock, SA_XLOCKED); 1069 1070 PROC_LOCK(p); 1071 1072 switch (idtype) { 1073 case P_ALL: 1074 if (p->p_procdesc == NULL || 1075 (p->p_pptr == td->td_proc && 1076 (p->p_flag & P_TRACED) != 0)) { 1077 break; 1078 } 1079 1080 PROC_UNLOCK(p); 1081 return (0); 1082 case P_PID: 1083 if (p->p_pid != (pid_t)id) { 1084 PROC_UNLOCK(p); 1085 return (0); 1086 } 1087 break; 1088 case P_PGID: 1089 if (p->p_pgid != (pid_t)id) { 1090 PROC_UNLOCK(p); 1091 return (0); 1092 } 1093 break; 1094 case P_SID: 1095 if (p->p_session->s_sid != (pid_t)id) { 1096 PROC_UNLOCK(p); 1097 return (0); 1098 } 1099 break; 1100 case P_UID: 1101 if (p->p_ucred->cr_uid != (uid_t)id) { 1102 PROC_UNLOCK(p); 1103 return (0); 1104 } 1105 break; 1106 case P_GID: 1107 if (p->p_ucred->cr_gid != (gid_t)id) { 1108 PROC_UNLOCK(p); 1109 return (0); 1110 } 1111 break; 1112 case P_JAILID: 1113 if (p->p_ucred->cr_prison->pr_id != (int)id) { 1114 PROC_UNLOCK(p); 1115 return (0); 1116 } 1117 break; 1118 /* 1119 * It seems that the thread structures get zeroed out 1120 * at process exit. This makes it impossible to 1121 * support P_SETID, P_CID or P_CPUID. 1122 */ 1123 default: 1124 PROC_UNLOCK(p); 1125 return (0); 1126 } 1127 1128 if (p_canwait(td, p)) { 1129 PROC_UNLOCK(p); 1130 return (0); 1131 } 1132 1133 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) { 1134 PROC_UNLOCK(p); 1135 return (0); 1136 } 1137 1138 /* 1139 * This special case handles a kthread spawned by linux_clone 1140 * (see linux_misc.c). The linux_wait4 and linux_waitpid 1141 * functions need to be able to distinguish between waiting 1142 * on a process and waiting on a thread. It is a thread if 1143 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 1144 * signifies we want to wait for threads and not processes. 1145 */ 1146 if ((p->p_sigparent != SIGCHLD) ^ 1147 ((options & WLINUXCLONE) != 0)) { 1148 PROC_UNLOCK(p); 1149 return (0); 1150 } 1151 1152 if (siginfo != NULL) { 1153 bzero(siginfo, sizeof(*siginfo)); 1154 siginfo->si_errno = 0; 1155 1156 /* 1157 * SUSv4 requires that the si_signo value is always 1158 * SIGCHLD. Obey it despite the rfork(2) interface 1159 * allows to request other signal for child exit 1160 * notification. 1161 */ 1162 siginfo->si_signo = SIGCHLD; 1163 1164 /* 1165 * This is still a rough estimate. We will fix the 1166 * cases TRAPPED, STOPPED, and CONTINUED later. 1167 */ 1168 if (WCOREDUMP(p->p_xsig)) { 1169 siginfo->si_code = CLD_DUMPED; 1170 siginfo->si_status = WTERMSIG(p->p_xsig); 1171 } else if (WIFSIGNALED(p->p_xsig)) { 1172 siginfo->si_code = CLD_KILLED; 1173 siginfo->si_status = WTERMSIG(p->p_xsig); 1174 } else { 1175 siginfo->si_code = CLD_EXITED; 1176 siginfo->si_status = p->p_xexit; 1177 } 1178 1179 siginfo->si_pid = p->p_pid; 1180 siginfo->si_uid = p->p_ucred->cr_uid; 1181 1182 /* 1183 * The si_addr field would be useful additional 1184 * detail, but apparently the PC value may be lost 1185 * when we reach this point. bzero() above sets 1186 * siginfo->si_addr to NULL. 1187 */ 1188 } 1189 1190 /* 1191 * There should be no reason to limit resources usage info to 1192 * exited processes only. A snapshot about any resources used 1193 * by a stopped process may be exactly what is needed. 1194 */ 1195 if (wrusage != NULL) { 1196 rup = &wrusage->wru_self; 1197 *rup = p->p_ru; 1198 PROC_STATLOCK(p); 1199 calcru(p, &rup->ru_utime, &rup->ru_stime); 1200 PROC_STATUNLOCK(p); 1201 1202 rup = &wrusage->wru_children; 1203 *rup = p->p_stats->p_cru; 1204 calccru(p, &rup->ru_utime, &rup->ru_stime); 1205 } 1206 1207 if (p->p_state == PRS_ZOMBIE && !check_only) { 1208 proc_reap(td, p, status, options); 1209 return (-1); 1210 } 1211 return (1); 1212 } 1213 1214 int 1215 kern_wait(struct thread *td, pid_t pid, int *status, int options, 1216 struct rusage *rusage) 1217 { 1218 struct __wrusage wru, *wrup; 1219 idtype_t idtype; 1220 id_t id; 1221 int ret; 1222 1223 /* 1224 * Translate the special pid values into the (idtype, pid) 1225 * pair for kern_wait6. The WAIT_MYPGRP case is handled by 1226 * kern_wait6() on its own. 1227 */ 1228 if (pid == WAIT_ANY) { 1229 idtype = P_ALL; 1230 id = 0; 1231 } else if (pid < 0) { 1232 idtype = P_PGID; 1233 id = (id_t)-pid; 1234 } else { 1235 idtype = P_PID; 1236 id = (id_t)pid; 1237 } 1238 1239 if (rusage != NULL) 1240 wrup = &wru; 1241 else 1242 wrup = NULL; 1243 1244 /* 1245 * For backward compatibility we implicitly add flags WEXITED 1246 * and WTRAPPED here. 1247 */ 1248 options |= WEXITED | WTRAPPED; 1249 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL); 1250 if (rusage != NULL) 1251 *rusage = wru.wru_self; 1252 return (ret); 1253 } 1254 1255 static void 1256 report_alive_proc(struct thread *td, struct proc *p, siginfo_t *siginfo, 1257 int *status, int options, int si_code) 1258 { 1259 bool cont; 1260 1261 PROC_LOCK_ASSERT(p, MA_OWNED); 1262 sx_assert(&proctree_lock, SA_XLOCKED); 1263 MPASS(si_code == CLD_TRAPPED || si_code == CLD_STOPPED || 1264 si_code == CLD_CONTINUED); 1265 1266 cont = si_code == CLD_CONTINUED; 1267 if ((options & WNOWAIT) == 0) { 1268 if (cont) 1269 p->p_flag &= ~P_CONTINUED; 1270 else 1271 p->p_flag |= P_WAITED; 1272 if (kern_wait_dequeue_sigchld && 1273 (td->td_proc->p_sysent->sv_flags & SV_SIG_WAITNDQ) == 0) { 1274 PROC_LOCK(td->td_proc); 1275 sigqueue_take(p->p_ksi); 1276 PROC_UNLOCK(td->td_proc); 1277 } 1278 } 1279 sx_xunlock(&proctree_lock); 1280 if (siginfo != NULL) { 1281 siginfo->si_code = si_code; 1282 siginfo->si_status = cont ? SIGCONT : p->p_xsig; 1283 } 1284 if (status != NULL) 1285 *status = cont ? SIGCONT : W_STOPCODE(p->p_xsig); 1286 td->td_retval[0] = p->p_pid; 1287 PROC_UNLOCK(p); 1288 } 1289 1290 int 1291 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status, 1292 int options, struct __wrusage *wrusage, siginfo_t *siginfo) 1293 { 1294 struct proc *p, *q; 1295 pid_t pid; 1296 int error, nfound, ret; 1297 bool report; 1298 1299 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */ 1300 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */ 1301 AUDIT_ARG_VALUE(options); 1302 1303 q = td->td_proc; 1304 1305 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { 1306 PROC_LOCK(q); 1307 id = (id_t)q->p_pgid; 1308 PROC_UNLOCK(q); 1309 idtype = P_PGID; 1310 } 1311 1312 /* If we don't know the option, just return. */ 1313 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT | 1314 WEXITED | WTRAPPED | WLINUXCLONE)) != 0) 1315 return (EINVAL); 1316 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) { 1317 /* 1318 * We will be unable to find any matching processes, 1319 * because there are no known events to look for. 1320 * Prefer to return error instead of blocking 1321 * indefinitely. 1322 */ 1323 return (EINVAL); 1324 } 1325 1326 loop: 1327 if (q->p_flag & P_STATCHILD) { 1328 PROC_LOCK(q); 1329 q->p_flag &= ~P_STATCHILD; 1330 PROC_UNLOCK(q); 1331 } 1332 sx_xlock(&proctree_lock); 1333 loop_locked: 1334 nfound = 0; 1335 LIST_FOREACH(p, &q->p_children, p_sibling) { 1336 pid = p->p_pid; 1337 ret = proc_to_reap(td, p, idtype, id, status, options, 1338 wrusage, siginfo, 0); 1339 if (ret == 0) 1340 continue; 1341 else if (ret != 1) { 1342 td->td_retval[0] = pid; 1343 return (0); 1344 } 1345 1346 nfound++; 1347 PROC_LOCK_ASSERT(p, MA_OWNED); 1348 1349 if ((options & WTRAPPED) != 0 && 1350 (p->p_flag & P_TRACED) != 0) { 1351 PROC_SLOCK(p); 1352 report = 1353 ((p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) && 1354 p->p_suspcount == p->p_numthreads && 1355 (p->p_flag & P_WAITED) == 0); 1356 PROC_SUNLOCK(p); 1357 if (report) { 1358 CTR4(KTR_PTRACE, 1359 "wait: returning trapped pid %d status %#x " 1360 "(xstat %d) xthread %d", 1361 p->p_pid, W_STOPCODE(p->p_xsig), p->p_xsig, 1362 p->p_xthread != NULL ? 1363 p->p_xthread->td_tid : -1); 1364 report_alive_proc(td, p, siginfo, status, 1365 options, CLD_TRAPPED); 1366 return (0); 1367 } 1368 } 1369 if ((options & WUNTRACED) != 0 && 1370 (p->p_flag & P_STOPPED_SIG) != 0) { 1371 PROC_SLOCK(p); 1372 report = (p->p_suspcount == p->p_numthreads && 1373 ((p->p_flag & P_WAITED) == 0)); 1374 PROC_SUNLOCK(p); 1375 if (report) { 1376 report_alive_proc(td, p, siginfo, status, 1377 options, CLD_STOPPED); 1378 return (0); 1379 } 1380 } 1381 if ((options & WCONTINUED) != 0 && 1382 (p->p_flag & P_CONTINUED) != 0) { 1383 report_alive_proc(td, p, siginfo, status, options, 1384 CLD_CONTINUED); 1385 return (0); 1386 } 1387 PROC_UNLOCK(p); 1388 } 1389 1390 /* 1391 * Look in the orphans list too, to allow the parent to 1392 * collect it's child exit status even if child is being 1393 * debugged. 1394 * 1395 * Debugger detaches from the parent upon successful 1396 * switch-over from parent to child. At this point due to 1397 * re-parenting the parent loses the child to debugger and a 1398 * wait4(2) call would report that it has no children to wait 1399 * for. By maintaining a list of orphans we allow the parent 1400 * to successfully wait until the child becomes a zombie. 1401 */ 1402 if (nfound == 0) { 1403 LIST_FOREACH(p, &q->p_orphans, p_orphan) { 1404 ret = proc_to_reap(td, p, idtype, id, NULL, options, 1405 NULL, NULL, 1); 1406 if (ret != 0) { 1407 KASSERT(ret != -1, ("reaped an orphan (pid %d)", 1408 (int)td->td_retval[0])); 1409 PROC_UNLOCK(p); 1410 nfound++; 1411 break; 1412 } 1413 } 1414 } 1415 if (nfound == 0) { 1416 sx_xunlock(&proctree_lock); 1417 return (ECHILD); 1418 } 1419 if (options & WNOHANG) { 1420 sx_xunlock(&proctree_lock); 1421 td->td_retval[0] = 0; 1422 return (0); 1423 } 1424 PROC_LOCK(q); 1425 if (q->p_flag & P_STATCHILD) { 1426 q->p_flag &= ~P_STATCHILD; 1427 PROC_UNLOCK(q); 1428 goto loop_locked; 1429 } 1430 sx_xunlock(&proctree_lock); 1431 error = msleep(q, &q->p_mtx, PWAIT | PCATCH | PDROP, "wait", 0); 1432 if (error) 1433 return (error); 1434 goto loop; 1435 } 1436 1437 void 1438 proc_add_orphan(struct proc *child, struct proc *parent) 1439 { 1440 1441 sx_assert(&proctree_lock, SX_XLOCKED); 1442 KASSERT((child->p_flag & P_TRACED) != 0, 1443 ("proc_add_orphan: not traced")); 1444 1445 if (LIST_EMPTY(&parent->p_orphans)) { 1446 child->p_treeflag |= P_TREE_FIRST_ORPHAN; 1447 LIST_INSERT_HEAD(&parent->p_orphans, child, p_orphan); 1448 } else { 1449 LIST_INSERT_AFTER(LIST_FIRST(&parent->p_orphans), 1450 child, p_orphan); 1451 } 1452 child->p_treeflag |= P_TREE_ORPHANED; 1453 } 1454 1455 /* 1456 * Make process 'parent' the new parent of process 'child'. 1457 * Must be called with an exclusive hold of proctree lock. 1458 */ 1459 void 1460 proc_reparent(struct proc *child, struct proc *parent, bool set_oppid) 1461 { 1462 1463 sx_assert(&proctree_lock, SX_XLOCKED); 1464 PROC_LOCK_ASSERT(child, MA_OWNED); 1465 if (child->p_pptr == parent) 1466 return; 1467 1468 PROC_LOCK(child->p_pptr); 1469 sigqueue_take(child->p_ksi); 1470 PROC_UNLOCK(child->p_pptr); 1471 LIST_REMOVE(child, p_sibling); 1472 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1473 1474 proc_clear_orphan(child); 1475 if ((child->p_flag & P_TRACED) != 0) { 1476 proc_add_orphan(child, child->p_pptr); 1477 } 1478 1479 child->p_pptr = parent; 1480 if (set_oppid) 1481 child->p_oppid = parent->p_pid; 1482 } 1483