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 while (p->p_singlethr > 0) 222 msleep(&p->p_singlethr, &p->p_mtx, PWAIT | PCATCH, "exit1t", 0); 223 } 224 225 /* 226 * Exit: deallocate address space and other resources, change proc state to 227 * zombie, and unlink proc from allproc and parent's lists. Save exit status 228 * and rusage for wait(). Check for child processes and orphan them. 229 */ 230 void 231 exit1(struct thread *td, int rval, int signo) 232 { 233 struct proc *p, *nq, *q, *t; 234 struct thread *tdt; 235 ksiginfo_t *ksi, *ksi1; 236 int signal_parent; 237 238 mtx_assert(&Giant, MA_NOTOWNED); 239 KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo)); 240 TSPROCEXIT(td->td_proc->p_pid); 241 242 p = td->td_proc; 243 /* 244 * XXX in case we're rebooting we just let init die in order to 245 * work around an unsolved stack overflow seen very late during 246 * shutdown on sparc64 when the gmirror worker process exists. 247 * XXX what to do now that sparc64 is gone... remove if? 248 */ 249 if (p == initproc && rebooting == 0) { 250 printf("init died (signal %d, exit %d)\n", signo, rval); 251 panic("Going nowhere without my init!"); 252 } 253 254 /* 255 * Process deferred operations, designated with ASTF_KCLEAR. 256 * For instance, we need to deref SU mp, since the thread does 257 * not return to userspace, and wait for geom to stabilize. 258 */ 259 ast_kclear(td); 260 261 /* 262 * MUST abort all other threads before proceeding past here. 263 */ 264 PROC_LOCK(p); 265 proc_set_p2_wexit(p); 266 267 /* 268 * First check if some other thread or external request got 269 * here before us. If so, act appropriately: exit or suspend. 270 * We must ensure that stop requests are handled before we set 271 * P_WEXIT. 272 */ 273 thread_suspend_check(0); 274 while (p->p_flag & P_HADTHREADS) { 275 /* 276 * Kill off the other threads. This requires 277 * some co-operation from other parts of the kernel 278 * so it may not be instantaneous. With this state set 279 * any thread entering the kernel from userspace will 280 * thread_exit() in trap(). Any thread attempting to 281 * sleep will return immediately with EINTR or EWOULDBLOCK 282 * which will hopefully force them to back out to userland 283 * freeing resources as they go. Any thread attempting 284 * to return to userland will thread_exit() from userret(). 285 * thread_exit() will unsuspend us when the last of the 286 * other threads exits. 287 * If there is already a thread singler after resumption, 288 * calling thread_single will fail; in that case, we just 289 * re-check all suspension request, the thread should 290 * either be suspended there or exit. 291 */ 292 if (!thread_single(p, SINGLE_EXIT)) 293 /* 294 * All other activity in this process is now 295 * stopped. Threading support has been turned 296 * off. 297 */ 298 break; 299 /* 300 * Recheck for new stop or suspend requests which 301 * might appear while process lock was dropped in 302 * thread_single(). 303 */ 304 thread_suspend_check(0); 305 } 306 KASSERT(p->p_numthreads == 1, 307 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 308 racct_sub(p, RACCT_NTHR, 1); 309 310 /* Let event handler change exit status */ 311 p->p_xexit = rval; 312 p->p_xsig = signo; 313 314 /* 315 * Ignore any pending request to stop due to a stop signal. 316 * Once P_WEXIT is set, future requests will be ignored as 317 * well. 318 */ 319 p->p_flag &= ~P_STOPPED_SIG; 320 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped")); 321 322 /* Note that we are exiting. */ 323 p->p_flag |= P_WEXIT; 324 325 /* 326 * Wait for any processes that have a hold on our vmspace to 327 * release their reference. 328 */ 329 while (p->p_lock > 0) 330 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 331 332 PROC_UNLOCK(p); 333 /* Drain the limit callout while we don't have the proc locked */ 334 callout_drain(&p->p_limco); 335 336 #ifdef AUDIT 337 /* 338 * The Sun BSM exit token contains two components: an exit status as 339 * passed to exit(), and a return value to indicate what sort of exit 340 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 341 * what the return value is. 342 */ 343 AUDIT_ARG_EXIT(rval, 0); 344 AUDIT_SYSCALL_EXIT(0, td); 345 #endif 346 347 /* Are we a task leader with peers? */ 348 if (p->p_peers != NULL && p == p->p_leader) { 349 mtx_lock(&ppeers_lock); 350 q = p->p_peers; 351 while (q != NULL) { 352 PROC_LOCK(q); 353 kern_psignal(q, SIGKILL); 354 PROC_UNLOCK(q); 355 q = q->p_peers; 356 } 357 while (p->p_peers != NULL) 358 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 359 mtx_unlock(&ppeers_lock); 360 } 361 362 itimers_exit(p); 363 364 /* 365 * Check if any loadable modules need anything done at process exit. 366 * E.g. SYSV IPC stuff. 367 * Event handler could change exit status. 368 * XXX what if one of these generates an error? 369 */ 370 EVENTHANDLER_DIRECT_INVOKE(process_exit, p); 371 372 /* 373 * If parent is waiting for us to exit or exec, 374 * P_PPWAIT is set; we will wakeup the parent below. 375 */ 376 PROC_LOCK(p); 377 stopprofclock(p); 378 p->p_ptevents = 0; 379 380 /* 381 * Stop the real interval timer. If the handler is currently 382 * executing, prevent it from rearming itself and let it finish. 383 */ 384 if (timevalisset(&p->p_realtimer.it_value) && 385 callout_stop(&p->p_itcallout) == 0) { 386 timevalclear(&p->p_realtimer.it_interval); 387 PROC_UNLOCK(p); 388 callout_drain(&p->p_itcallout); 389 } else { 390 PROC_UNLOCK(p); 391 } 392 393 if (p->p_sysent->sv_onexit != NULL) 394 p->p_sysent->sv_onexit(p); 395 seltdfini(td); 396 397 /* 398 * Reset any sigio structures pointing to us as a result of 399 * F_SETOWN with our pid. The P_WEXIT flag interlocks with fsetown(). 400 */ 401 funsetownlst(&p->p_sigiolst); 402 403 /* 404 * Close open files and release open-file table. 405 * This may block! 406 */ 407 pdescfree(td); 408 fdescfree(td); 409 410 /* 411 * Remove ourself from our leader's peer list and wake our leader. 412 */ 413 if (p->p_leader->p_peers != NULL) { 414 mtx_lock(&ppeers_lock); 415 if (p->p_leader->p_peers != NULL) { 416 q = p->p_leader; 417 while (q->p_peers != p) 418 q = q->p_peers; 419 q->p_peers = p->p_peers; 420 wakeup(p->p_leader); 421 } 422 mtx_unlock(&ppeers_lock); 423 } 424 425 exec_free_abi_mappings(p); 426 vmspace_exit(td); 427 (void)acct_process(td); 428 429 #ifdef KTRACE 430 ktrprocexit(td); 431 #endif 432 /* 433 * Release reference to text vnode etc 434 */ 435 if (p->p_textvp != NULL) { 436 vrele(p->p_textvp); 437 p->p_textvp = NULL; 438 } 439 if (p->p_textdvp != NULL) { 440 vrele(p->p_textdvp); 441 p->p_textdvp = NULL; 442 } 443 if (p->p_binname != NULL) { 444 free(p->p_binname, M_PARGS); 445 p->p_binname = NULL; 446 } 447 448 /* 449 * Release our limits structure. 450 */ 451 lim_free(p->p_limit); 452 p->p_limit = NULL; 453 454 tidhash_remove(td); 455 456 /* 457 * Call machine-dependent code to release any 458 * machine-dependent resources other than the address space. 459 * The address space is released by "vmspace_exitfree(p)" in 460 * vm_waitproc(). 461 */ 462 cpu_exit(td); 463 464 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 465 466 /* 467 * Remove from allproc. It still sits in the hash. 468 */ 469 sx_xlock(&allproc_lock); 470 LIST_REMOVE(p, p_list); 471 472 #ifdef DDB 473 /* 474 * Used by ddb's 'ps' command to find this process via the 475 * pidhash. 476 */ 477 p->p_list.le_prev = NULL; 478 #endif 479 sx_xunlock(&allproc_lock); 480 481 sx_xlock(&proctree_lock); 482 PROC_LOCK(p); 483 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE); 484 PROC_UNLOCK(p); 485 486 /* 487 * killjobc() might drop and re-acquire proctree_lock to 488 * revoke control tty if exiting process was a session leader. 489 */ 490 killjobc(); 491 492 /* 493 * Reparent all children processes: 494 * - traced ones to the original parent (or init if we are that parent) 495 * - the rest to init 496 */ 497 q = LIST_FIRST(&p->p_children); 498 if (q != NULL) /* only need this if any child is S_ZOMB */ 499 wakeup(q->p_reaper); 500 for (; q != NULL; q = nq) { 501 nq = LIST_NEXT(q, p_sibling); 502 ksi = ksiginfo_alloc(TRUE); 503 PROC_LOCK(q); 504 q->p_sigparent = SIGCHLD; 505 506 if ((q->p_flag & P_TRACED) == 0) { 507 proc_reparent(q, q->p_reaper, true); 508 if (q->p_state == PRS_ZOMBIE) { 509 /* 510 * Inform reaper about the reparented 511 * zombie, since wait(2) has something 512 * new to report. Guarantee queueing 513 * of the SIGCHLD signal, similar to 514 * the _exit() behaviour, by providing 515 * our ksiginfo. Ksi is freed by the 516 * signal delivery. 517 */ 518 if (q->p_ksi == NULL) { 519 ksi1 = NULL; 520 } else { 521 ksiginfo_copy(q->p_ksi, ksi); 522 ksi->ksi_flags |= KSI_INS; 523 ksi1 = ksi; 524 ksi = NULL; 525 } 526 PROC_LOCK(q->p_reaper); 527 pksignal(q->p_reaper, SIGCHLD, ksi1); 528 PROC_UNLOCK(q->p_reaper); 529 } else if (q->p_pdeathsig > 0) { 530 /* 531 * The child asked to received a signal 532 * when we exit. 533 */ 534 kern_psignal(q, q->p_pdeathsig); 535 } 536 } else { 537 /* 538 * Traced processes are killed by default 539 * since their existence means someone is 540 * screwing up. 541 */ 542 t = proc_realparent(q); 543 if (t == p) { 544 proc_reparent(q, q->p_reaper, true); 545 } else { 546 PROC_LOCK(t); 547 proc_reparent(q, t, true); 548 PROC_UNLOCK(t); 549 } 550 /* 551 * Since q was found on our children list, the 552 * proc_reparent() call moved q to the orphan 553 * list due to present P_TRACED flag. Clear 554 * orphan link for q now while q is locked. 555 */ 556 proc_clear_orphan(q); 557 q->p_flag &= ~P_TRACED; 558 q->p_flag2 &= ~P2_PTRACE_FSTP; 559 q->p_ptevents = 0; 560 p->p_xthread = NULL; 561 FOREACH_THREAD_IN_PROC(q, tdt) { 562 tdt->td_dbgflags &= ~(TDB_SUSPEND | TDB_XSIG | 563 TDB_FSTP); 564 tdt->td_xsig = 0; 565 } 566 if (kern_kill_on_dbg_exit) { 567 q->p_flag &= ~P_STOPPED_TRACE; 568 kern_psignal(q, SIGKILL); 569 } else if ((q->p_flag & (P_STOPPED_TRACE | 570 P_STOPPED_SIG)) != 0) { 571 sigqueue_delete_proc(q, SIGTRAP); 572 ptrace_unsuspend(q); 573 } 574 } 575 PROC_UNLOCK(q); 576 if (ksi != NULL) 577 ksiginfo_free(ksi); 578 } 579 580 /* 581 * Also get rid of our orphans. 582 */ 583 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) { 584 PROC_LOCK(q); 585 KASSERT(q->p_oppid == p->p_pid, 586 ("orphan %p of %p has unexpected oppid %d", q, p, 587 q->p_oppid)); 588 q->p_oppid = q->p_reaper->p_pid; 589 590 /* 591 * If we are the real parent of this process 592 * but it has been reparented to a debugger, then 593 * check if it asked for a signal when we exit. 594 */ 595 if (q->p_pdeathsig > 0) 596 kern_psignal(q, q->p_pdeathsig); 597 CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid, 598 q->p_pid); 599 proc_clear_orphan(q); 600 PROC_UNLOCK(q); 601 } 602 603 #ifdef KDTRACE_HOOKS 604 if (SDT_PROBES_ENABLED()) { 605 int reason = CLD_EXITED; 606 if (WCOREDUMP(signo)) 607 reason = CLD_DUMPED; 608 else if (WIFSIGNALED(signo)) 609 reason = CLD_KILLED; 610 SDT_PROBE1(proc, , , exit, reason); 611 } 612 #endif 613 614 /* Save exit status. */ 615 PROC_LOCK(p); 616 p->p_xthread = td; 617 618 if (p->p_sysent->sv_ontdexit != NULL) 619 p->p_sysent->sv_ontdexit(td); 620 621 #ifdef KDTRACE_HOOKS 622 /* 623 * Tell the DTrace fasttrap provider about the exit if it 624 * has declared an interest. 625 */ 626 if (dtrace_fasttrap_exit) 627 dtrace_fasttrap_exit(p); 628 #endif 629 630 /* 631 * Notify interested parties of our demise. 632 */ 633 KNOTE_LOCKED(p->p_klist, NOTE_EXIT); 634 635 /* 636 * If this is a process with a descriptor, we may not need to deliver 637 * a signal to the parent. proctree_lock is held over 638 * procdesc_exit() to serialize concurrent calls to close() and 639 * exit(). 640 */ 641 signal_parent = 0; 642 if (p->p_procdesc == NULL || procdesc_exit(p)) { 643 /* 644 * Notify parent that we're gone. If parent has the 645 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN, 646 * notify process 1 instead (and hope it will handle this 647 * situation). 648 */ 649 PROC_LOCK(p->p_pptr); 650 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 651 if (p->p_pptr->p_sigacts->ps_flag & 652 (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 653 struct proc *pp; 654 655 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 656 pp = p->p_pptr; 657 PROC_UNLOCK(pp); 658 proc_reparent(p, p->p_reaper, true); 659 p->p_sigparent = SIGCHLD; 660 PROC_LOCK(p->p_pptr); 661 662 /* 663 * Notify parent, so in case he was wait(2)ing or 664 * executing waitpid(2) with our pid, he will 665 * continue. 666 */ 667 wakeup(pp); 668 } else 669 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 670 671 if (p->p_pptr == p->p_reaper || p->p_pptr == initproc) { 672 signal_parent = 1; 673 } else if (p->p_sigparent != 0) { 674 if (p->p_sigparent == SIGCHLD) { 675 signal_parent = 1; 676 } else { /* LINUX thread */ 677 signal_parent = 2; 678 } 679 } 680 } else 681 PROC_LOCK(p->p_pptr); 682 sx_xunlock(&proctree_lock); 683 684 if (signal_parent == 1) { 685 childproc_exited(p); 686 } else if (signal_parent == 2) { 687 kern_psignal(p->p_pptr, p->p_sigparent); 688 } 689 690 /* Tell the prison that we are gone. */ 691 prison_proc_free(p->p_ucred->cr_prison); 692 693 /* 694 * The state PRS_ZOMBIE prevents other proesses from sending 695 * signal to the process, to avoid memory leak, we free memory 696 * for signal queue at the time when the state is set. 697 */ 698 sigqueue_flush(&p->p_sigqueue); 699 sigqueue_flush(&td->td_sigqueue); 700 701 /* 702 * We have to wait until after acquiring all locks before 703 * changing p_state. We need to avoid all possible context 704 * switches (including ones from blocking on a mutex) while 705 * marked as a zombie. We also have to set the zombie state 706 * before we release the parent process' proc lock to avoid 707 * a lost wakeup. So, we first call wakeup, then we grab the 708 * sched lock, update the state, and release the parent process' 709 * proc lock. 710 */ 711 wakeup(p->p_pptr); 712 cv_broadcast(&p->p_pwait); 713 sched_exit(p->p_pptr, td); 714 PROC_SLOCK(p); 715 p->p_state = PRS_ZOMBIE; 716 PROC_UNLOCK(p->p_pptr); 717 718 /* 719 * Save our children's rusage information in our exit rusage. 720 */ 721 PROC_STATLOCK(p); 722 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 723 PROC_STATUNLOCK(p); 724 725 /* 726 * Make sure the scheduler takes this thread out of its tables etc. 727 * This will also release this thread's reference to the ucred. 728 * Other thread parts to release include pcb bits and such. 729 */ 730 thread_exit(); 731 } 732 733 #ifndef _SYS_SYSPROTO_H_ 734 struct abort2_args { 735 char *why; 736 int nargs; 737 void **args; 738 }; 739 #endif 740 741 int 742 sys_abort2(struct thread *td, struct abort2_args *uap) 743 { 744 void *uargs[16]; 745 void **uargsp; 746 int error, nargs; 747 748 nargs = uap->nargs; 749 if (nargs < 0 || nargs > nitems(uargs)) 750 nargs = -1; 751 uargsp = NULL; 752 if (nargs > 0) { 753 if (uap->args != NULL) { 754 error = copyin(uap->args, uargs, 755 nargs * sizeof(void *)); 756 if (error != 0) 757 nargs = -1; 758 else 759 uargsp = uargs; 760 } else 761 nargs = -1; 762 } 763 return (kern_abort2(td, uap->why, nargs, uargsp)); 764 } 765 766 /* 767 * kern_abort2() 768 * Arguments: 769 * why - user pointer to why 770 * nargs - number of arguments copied or -1 if an error occured in copying 771 * args - pointer to an array of pointers in kernel format 772 */ 773 int 774 kern_abort2(struct thread *td, const char *why, int nargs, void **uargs) 775 { 776 struct proc *p = td->td_proc; 777 struct sbuf *sb; 778 int error, i, sig; 779 780 /* 781 * Do it right now so we can log either proper call of abort2(), or 782 * note, that invalid argument was passed. 512 is big enough to 783 * handle 16 arguments' descriptions with additional comments. 784 */ 785 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 786 sbuf_clear(sb); 787 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 788 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 789 /* 790 * Since we can't return from abort2(), send SIGKILL in cases, where 791 * abort2() was called improperly 792 */ 793 sig = SIGKILL; 794 /* Prevent from DoSes from user-space. */ 795 if (nargs == -1) 796 goto out; 797 KASSERT(nargs >= 0 && nargs <= 16, ("called with too many args (%d)", 798 nargs)); 799 /* 800 * Limit size of 'reason' string to 128. Will fit even when 801 * maximal number of arguments was chosen to be logged. 802 */ 803 if (why != NULL) { 804 error = sbuf_copyin(sb, why, 128); 805 if (error < 0) 806 goto out; 807 } else { 808 sbuf_printf(sb, "(null)"); 809 } 810 if (nargs > 0) { 811 sbuf_printf(sb, "("); 812 for (i = 0;i < nargs; i++) 813 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 814 sbuf_printf(sb, ")"); 815 } 816 /* 817 * Final stage: arguments were proper, string has been 818 * successfully copied from userspace, and copying pointers 819 * from user-space succeed. 820 */ 821 sig = SIGABRT; 822 out: 823 if (sig == SIGKILL) { 824 sbuf_trim(sb); 825 sbuf_printf(sb, " (Reason text inaccessible)"); 826 } 827 sbuf_cat(sb, "\n"); 828 sbuf_finish(sb); 829 log(LOG_INFO, "%s", sbuf_data(sb)); 830 sbuf_delete(sb); 831 exit1(td, 0, sig); 832 return (0); 833 } 834 835 #ifdef COMPAT_43 836 /* 837 * The dirty work is handled by kern_wait(). 838 */ 839 int 840 owait(struct thread *td, struct owait_args *uap __unused) 841 { 842 int error, status; 843 844 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 845 if (error == 0) 846 td->td_retval[1] = status; 847 return (error); 848 } 849 #endif /* COMPAT_43 */ 850 851 /* 852 * The dirty work is handled by kern_wait(). 853 */ 854 int 855 sys_wait4(struct thread *td, struct wait4_args *uap) 856 { 857 struct rusage ru, *rup; 858 int error, status; 859 860 if (uap->rusage != NULL) 861 rup = &ru; 862 else 863 rup = NULL; 864 error = kern_wait(td, uap->pid, &status, uap->options, rup); 865 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0) 866 error = copyout(&status, uap->status, sizeof(status)); 867 if (uap->rusage != NULL && error == 0 && td->td_retval[0] != 0) 868 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 869 return (error); 870 } 871 872 int 873 sys_wait6(struct thread *td, struct wait6_args *uap) 874 { 875 struct __wrusage wru, *wrup; 876 siginfo_t si, *sip; 877 idtype_t idtype; 878 id_t id; 879 int error, status; 880 881 idtype = uap->idtype; 882 id = uap->id; 883 884 if (uap->wrusage != NULL) 885 wrup = &wru; 886 else 887 wrup = NULL; 888 889 if (uap->info != NULL) { 890 sip = &si; 891 bzero(sip, sizeof(*sip)); 892 } else 893 sip = NULL; 894 895 /* 896 * We expect all callers of wait6() to know about WEXITED and 897 * WTRAPPED. 898 */ 899 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip); 900 901 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0) 902 error = copyout(&status, uap->status, sizeof(status)); 903 if (uap->wrusage != NULL && error == 0 && td->td_retval[0] != 0) 904 error = copyout(&wru, uap->wrusage, sizeof(wru)); 905 if (uap->info != NULL && error == 0) 906 error = copyout(&si, uap->info, sizeof(si)); 907 return (error); 908 } 909 910 /* 911 * Reap the remains of a zombie process and optionally return status and 912 * rusage. Asserts and will release both the proctree_lock and the process 913 * lock as part of its work. 914 */ 915 void 916 proc_reap(struct thread *td, struct proc *p, int *status, int options) 917 { 918 struct proc *q, *t; 919 920 sx_assert(&proctree_lock, SA_XLOCKED); 921 PROC_LOCK_ASSERT(p, MA_OWNED); 922 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 923 924 mtx_spin_wait_unlocked(&p->p_slock); 925 926 q = td->td_proc; 927 928 if (status) 929 *status = KW_EXITCODE(p->p_xexit, p->p_xsig); 930 if (options & WNOWAIT) { 931 /* 932 * Only poll, returning the status. Caller does not wish to 933 * release the proc struct just yet. 934 */ 935 PROC_UNLOCK(p); 936 sx_xunlock(&proctree_lock); 937 return; 938 } 939 940 PROC_LOCK(q); 941 sigqueue_take(p->p_ksi); 942 PROC_UNLOCK(q); 943 944 /* 945 * If we got the child via a ptrace 'attach', we need to give it back 946 * to the old parent. 947 */ 948 if (p->p_oppid != p->p_pptr->p_pid) { 949 PROC_UNLOCK(p); 950 t = proc_realparent(p); 951 PROC_LOCK(t); 952 PROC_LOCK(p); 953 CTR2(KTR_PTRACE, 954 "wait: traced child %d moved back to parent %d", p->p_pid, 955 t->p_pid); 956 proc_reparent(p, t, false); 957 PROC_UNLOCK(p); 958 pksignal(t, SIGCHLD, p->p_ksi); 959 wakeup(t); 960 cv_broadcast(&p->p_pwait); 961 PROC_UNLOCK(t); 962 sx_xunlock(&proctree_lock); 963 return; 964 } 965 PROC_UNLOCK(p); 966 967 /* 968 * Remove other references to this process to ensure we have an 969 * exclusive reference. 970 */ 971 sx_xlock(PIDHASHLOCK(p->p_pid)); 972 LIST_REMOVE(p, p_hash); 973 sx_xunlock(PIDHASHLOCK(p->p_pid)); 974 LIST_REMOVE(p, p_sibling); 975 reaper_abandon_children(p, true); 976 reaper_clear(p); 977 PROC_LOCK(p); 978 proc_clear_orphan(p); 979 PROC_UNLOCK(p); 980 leavepgrp(p); 981 if (p->p_procdesc != NULL) 982 procdesc_reap(p); 983 sx_xunlock(&proctree_lock); 984 985 proc_id_clear(PROC_ID_PID, p->p_pid); 986 987 PROC_LOCK(p); 988 knlist_detach(p->p_klist); 989 p->p_klist = NULL; 990 PROC_UNLOCK(p); 991 992 /* 993 * Removal from allproc list and process group list paired with 994 * PROC_LOCK which was executed during that time should guarantee 995 * nothing can reach this process anymore. As such further locking 996 * is unnecessary. 997 */ 998 p->p_xexit = p->p_xsig = 0; /* XXX: why? */ 999 1000 PROC_LOCK(q); 1001 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 1002 PROC_UNLOCK(q); 1003 1004 /* 1005 * Decrement the count of procs running with this uid. 1006 */ 1007 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 1008 1009 /* 1010 * Destroy resource accounting information associated with the process. 1011 */ 1012 #ifdef RACCT 1013 if (racct_enable) { 1014 PROC_LOCK(p); 1015 racct_sub(p, RACCT_NPROC, 1); 1016 PROC_UNLOCK(p); 1017 } 1018 #endif 1019 racct_proc_exit(p); 1020 1021 /* 1022 * Free credentials, arguments, and sigacts. 1023 */ 1024 proc_unset_cred(p); 1025 pargs_drop(p->p_args); 1026 p->p_args = NULL; 1027 sigacts_free(p->p_sigacts); 1028 p->p_sigacts = NULL; 1029 1030 /* 1031 * Do any thread-system specific cleanups. 1032 */ 1033 thread_wait(p); 1034 1035 /* 1036 * Give vm and machine-dependent layer a chance to free anything that 1037 * cpu_exit couldn't release while still running in process context. 1038 */ 1039 vm_waitproc(p); 1040 #ifdef MAC 1041 mac_proc_destroy(p); 1042 #endif 1043 1044 KASSERT(FIRST_THREAD_IN_PROC(p), 1045 ("proc_reap: no residual thread!")); 1046 uma_zfree(proc_zone, p); 1047 atomic_add_int(&nprocs, -1); 1048 } 1049 1050 static int 1051 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id, 1052 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo, 1053 int check_only) 1054 { 1055 struct rusage *rup; 1056 1057 sx_assert(&proctree_lock, SA_XLOCKED); 1058 1059 PROC_LOCK(p); 1060 1061 switch (idtype) { 1062 case P_ALL: 1063 if (p->p_procdesc == NULL || 1064 (p->p_pptr == td->td_proc && 1065 (p->p_flag & P_TRACED) != 0)) { 1066 break; 1067 } 1068 1069 PROC_UNLOCK(p); 1070 return (0); 1071 case P_PID: 1072 if (p->p_pid != (pid_t)id) { 1073 PROC_UNLOCK(p); 1074 return (0); 1075 } 1076 break; 1077 case P_PGID: 1078 if (p->p_pgid != (pid_t)id) { 1079 PROC_UNLOCK(p); 1080 return (0); 1081 } 1082 break; 1083 case P_SID: 1084 if (p->p_session->s_sid != (pid_t)id) { 1085 PROC_UNLOCK(p); 1086 return (0); 1087 } 1088 break; 1089 case P_UID: 1090 if (p->p_ucred->cr_uid != (uid_t)id) { 1091 PROC_UNLOCK(p); 1092 return (0); 1093 } 1094 break; 1095 case P_GID: 1096 if (p->p_ucred->cr_gid != (gid_t)id) { 1097 PROC_UNLOCK(p); 1098 return (0); 1099 } 1100 break; 1101 case P_JAILID: 1102 if (p->p_ucred->cr_prison->pr_id != (int)id) { 1103 PROC_UNLOCK(p); 1104 return (0); 1105 } 1106 break; 1107 /* 1108 * It seems that the thread structures get zeroed out 1109 * at process exit. This makes it impossible to 1110 * support P_SETID, P_CID or P_CPUID. 1111 */ 1112 default: 1113 PROC_UNLOCK(p); 1114 return (0); 1115 } 1116 1117 if (p_canwait(td, p)) { 1118 PROC_UNLOCK(p); 1119 return (0); 1120 } 1121 1122 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) { 1123 PROC_UNLOCK(p); 1124 return (0); 1125 } 1126 1127 /* 1128 * This special case handles a kthread spawned by linux_clone 1129 * (see linux_misc.c). The linux_wait4 and linux_waitpid 1130 * functions need to be able to distinguish between waiting 1131 * on a process and waiting on a thread. It is a thread if 1132 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 1133 * signifies we want to wait for threads and not processes. 1134 */ 1135 if ((p->p_sigparent != SIGCHLD) ^ 1136 ((options & WLINUXCLONE) != 0)) { 1137 PROC_UNLOCK(p); 1138 return (0); 1139 } 1140 1141 if (siginfo != NULL) { 1142 bzero(siginfo, sizeof(*siginfo)); 1143 siginfo->si_errno = 0; 1144 1145 /* 1146 * SUSv4 requires that the si_signo value is always 1147 * SIGCHLD. Obey it despite the rfork(2) interface 1148 * allows to request other signal for child exit 1149 * notification. 1150 */ 1151 siginfo->si_signo = SIGCHLD; 1152 1153 /* 1154 * This is still a rough estimate. We will fix the 1155 * cases TRAPPED, STOPPED, and CONTINUED later. 1156 */ 1157 if (WCOREDUMP(p->p_xsig)) { 1158 siginfo->si_code = CLD_DUMPED; 1159 siginfo->si_status = WTERMSIG(p->p_xsig); 1160 } else if (WIFSIGNALED(p->p_xsig)) { 1161 siginfo->si_code = CLD_KILLED; 1162 siginfo->si_status = WTERMSIG(p->p_xsig); 1163 } else { 1164 siginfo->si_code = CLD_EXITED; 1165 siginfo->si_status = p->p_xexit; 1166 } 1167 1168 siginfo->si_pid = p->p_pid; 1169 siginfo->si_uid = p->p_ucred->cr_uid; 1170 1171 /* 1172 * The si_addr field would be useful additional 1173 * detail, but apparently the PC value may be lost 1174 * when we reach this point. bzero() above sets 1175 * siginfo->si_addr to NULL. 1176 */ 1177 } 1178 1179 /* 1180 * There should be no reason to limit resources usage info to 1181 * exited processes only. A snapshot about any resources used 1182 * by a stopped process may be exactly what is needed. 1183 */ 1184 if (wrusage != NULL) { 1185 rup = &wrusage->wru_self; 1186 *rup = p->p_ru; 1187 PROC_STATLOCK(p); 1188 calcru(p, &rup->ru_utime, &rup->ru_stime); 1189 PROC_STATUNLOCK(p); 1190 1191 rup = &wrusage->wru_children; 1192 *rup = p->p_stats->p_cru; 1193 calccru(p, &rup->ru_utime, &rup->ru_stime); 1194 } 1195 1196 if (p->p_state == PRS_ZOMBIE && !check_only) { 1197 proc_reap(td, p, status, options); 1198 return (-1); 1199 } 1200 return (1); 1201 } 1202 1203 int 1204 kern_wait(struct thread *td, pid_t pid, int *status, int options, 1205 struct rusage *rusage) 1206 { 1207 struct __wrusage wru, *wrup; 1208 idtype_t idtype; 1209 id_t id; 1210 int ret; 1211 1212 /* 1213 * Translate the special pid values into the (idtype, pid) 1214 * pair for kern_wait6. The WAIT_MYPGRP case is handled by 1215 * kern_wait6() on its own. 1216 */ 1217 if (pid == WAIT_ANY) { 1218 idtype = P_ALL; 1219 id = 0; 1220 } else if (pid < 0) { 1221 idtype = P_PGID; 1222 id = (id_t)-pid; 1223 } else { 1224 idtype = P_PID; 1225 id = (id_t)pid; 1226 } 1227 1228 if (rusage != NULL) 1229 wrup = &wru; 1230 else 1231 wrup = NULL; 1232 1233 /* 1234 * For backward compatibility we implicitly add flags WEXITED 1235 * and WTRAPPED here. 1236 */ 1237 options |= WEXITED | WTRAPPED; 1238 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL); 1239 if (rusage != NULL) 1240 *rusage = wru.wru_self; 1241 return (ret); 1242 } 1243 1244 static void 1245 report_alive_proc(struct thread *td, struct proc *p, siginfo_t *siginfo, 1246 int *status, int options, int si_code) 1247 { 1248 bool cont; 1249 1250 PROC_LOCK_ASSERT(p, MA_OWNED); 1251 sx_assert(&proctree_lock, SA_XLOCKED); 1252 MPASS(si_code == CLD_TRAPPED || si_code == CLD_STOPPED || 1253 si_code == CLD_CONTINUED); 1254 1255 cont = si_code == CLD_CONTINUED; 1256 if ((options & WNOWAIT) == 0) { 1257 if (cont) 1258 p->p_flag &= ~P_CONTINUED; 1259 else 1260 p->p_flag |= P_WAITED; 1261 if (kern_wait_dequeue_sigchld && 1262 (td->td_proc->p_sysent->sv_flags & SV_SIG_WAITNDQ) == 0) { 1263 PROC_LOCK(td->td_proc); 1264 sigqueue_take(p->p_ksi); 1265 PROC_UNLOCK(td->td_proc); 1266 } 1267 } 1268 sx_xunlock(&proctree_lock); 1269 if (siginfo != NULL) { 1270 siginfo->si_code = si_code; 1271 siginfo->si_status = cont ? SIGCONT : p->p_xsig; 1272 } 1273 if (status != NULL) 1274 *status = cont ? SIGCONT : W_STOPCODE(p->p_xsig); 1275 PROC_UNLOCK(p); 1276 td->td_retval[0] = p->p_pid; 1277 } 1278 1279 int 1280 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status, 1281 int options, struct __wrusage *wrusage, siginfo_t *siginfo) 1282 { 1283 struct proc *p, *q; 1284 pid_t pid; 1285 int error, nfound, ret; 1286 bool report; 1287 1288 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */ 1289 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */ 1290 AUDIT_ARG_VALUE(options); 1291 1292 q = td->td_proc; 1293 1294 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { 1295 PROC_LOCK(q); 1296 id = (id_t)q->p_pgid; 1297 PROC_UNLOCK(q); 1298 idtype = P_PGID; 1299 } 1300 1301 /* If we don't know the option, just return. */ 1302 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT | 1303 WEXITED | WTRAPPED | WLINUXCLONE)) != 0) 1304 return (EINVAL); 1305 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) { 1306 /* 1307 * We will be unable to find any matching processes, 1308 * because there are no known events to look for. 1309 * Prefer to return error instead of blocking 1310 * indefinitely. 1311 */ 1312 return (EINVAL); 1313 } 1314 1315 loop: 1316 if (q->p_flag & P_STATCHILD) { 1317 PROC_LOCK(q); 1318 q->p_flag &= ~P_STATCHILD; 1319 PROC_UNLOCK(q); 1320 } 1321 sx_xlock(&proctree_lock); 1322 loop_locked: 1323 nfound = 0; 1324 LIST_FOREACH(p, &q->p_children, p_sibling) { 1325 pid = p->p_pid; 1326 ret = proc_to_reap(td, p, idtype, id, status, options, 1327 wrusage, siginfo, 0); 1328 if (ret == 0) 1329 continue; 1330 else if (ret != 1) { 1331 td->td_retval[0] = pid; 1332 return (0); 1333 } 1334 1335 nfound++; 1336 PROC_LOCK_ASSERT(p, MA_OWNED); 1337 1338 if ((options & WTRAPPED) != 0 && 1339 (p->p_flag & P_TRACED) != 0) { 1340 PROC_SLOCK(p); 1341 report = 1342 ((p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) && 1343 p->p_suspcount == p->p_numthreads && 1344 (p->p_flag & P_WAITED) == 0); 1345 PROC_SUNLOCK(p); 1346 if (report) { 1347 CTR4(KTR_PTRACE, 1348 "wait: returning trapped pid %d status %#x " 1349 "(xstat %d) xthread %d", 1350 p->p_pid, W_STOPCODE(p->p_xsig), p->p_xsig, 1351 p->p_xthread != NULL ? 1352 p->p_xthread->td_tid : -1); 1353 report_alive_proc(td, p, siginfo, status, 1354 options, CLD_TRAPPED); 1355 return (0); 1356 } 1357 } 1358 if ((options & WUNTRACED) != 0 && 1359 (p->p_flag & P_STOPPED_SIG) != 0) { 1360 PROC_SLOCK(p); 1361 report = (p->p_suspcount == p->p_numthreads && 1362 ((p->p_flag & P_WAITED) == 0)); 1363 PROC_SUNLOCK(p); 1364 if (report) { 1365 report_alive_proc(td, p, siginfo, status, 1366 options, CLD_STOPPED); 1367 return (0); 1368 } 1369 } 1370 if ((options & WCONTINUED) != 0 && 1371 (p->p_flag & P_CONTINUED) != 0) { 1372 report_alive_proc(td, p, siginfo, status, options, 1373 CLD_CONTINUED); 1374 return (0); 1375 } 1376 PROC_UNLOCK(p); 1377 } 1378 1379 /* 1380 * Look in the orphans list too, to allow the parent to 1381 * collect it's child exit status even if child is being 1382 * debugged. 1383 * 1384 * Debugger detaches from the parent upon successful 1385 * switch-over from parent to child. At this point due to 1386 * re-parenting the parent loses the child to debugger and a 1387 * wait4(2) call would report that it has no children to wait 1388 * for. By maintaining a list of orphans we allow the parent 1389 * to successfully wait until the child becomes a zombie. 1390 */ 1391 if (nfound == 0) { 1392 LIST_FOREACH(p, &q->p_orphans, p_orphan) { 1393 ret = proc_to_reap(td, p, idtype, id, NULL, options, 1394 NULL, NULL, 1); 1395 if (ret != 0) { 1396 KASSERT(ret != -1, ("reaped an orphan (pid %d)", 1397 (int)td->td_retval[0])); 1398 PROC_UNLOCK(p); 1399 nfound++; 1400 break; 1401 } 1402 } 1403 } 1404 if (nfound == 0) { 1405 sx_xunlock(&proctree_lock); 1406 return (ECHILD); 1407 } 1408 if (options & WNOHANG) { 1409 sx_xunlock(&proctree_lock); 1410 td->td_retval[0] = 0; 1411 return (0); 1412 } 1413 PROC_LOCK(q); 1414 if (q->p_flag & P_STATCHILD) { 1415 q->p_flag &= ~P_STATCHILD; 1416 PROC_UNLOCK(q); 1417 goto loop_locked; 1418 } 1419 sx_xunlock(&proctree_lock); 1420 error = msleep(q, &q->p_mtx, PWAIT | PCATCH | PDROP, "wait", 0); 1421 if (error) 1422 return (error); 1423 goto loop; 1424 } 1425 1426 void 1427 proc_add_orphan(struct proc *child, struct proc *parent) 1428 { 1429 1430 sx_assert(&proctree_lock, SX_XLOCKED); 1431 KASSERT((child->p_flag & P_TRACED) != 0, 1432 ("proc_add_orphan: not traced")); 1433 1434 if (LIST_EMPTY(&parent->p_orphans)) { 1435 child->p_treeflag |= P_TREE_FIRST_ORPHAN; 1436 LIST_INSERT_HEAD(&parent->p_orphans, child, p_orphan); 1437 } else { 1438 LIST_INSERT_AFTER(LIST_FIRST(&parent->p_orphans), 1439 child, p_orphan); 1440 } 1441 child->p_treeflag |= P_TREE_ORPHANED; 1442 } 1443 1444 /* 1445 * Make process 'parent' the new parent of process 'child'. 1446 * Must be called with an exclusive hold of proctree lock. 1447 */ 1448 void 1449 proc_reparent(struct proc *child, struct proc *parent, bool set_oppid) 1450 { 1451 1452 sx_assert(&proctree_lock, SX_XLOCKED); 1453 PROC_LOCK_ASSERT(child, MA_OWNED); 1454 if (child->p_pptr == parent) 1455 return; 1456 1457 PROC_LOCK(child->p_pptr); 1458 sigqueue_take(child->p_ksi); 1459 PROC_UNLOCK(child->p_pptr); 1460 LIST_REMOVE(child, p_sibling); 1461 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1462 1463 proc_clear_orphan(child); 1464 if ((child->p_flag & P_TRACED) != 0) { 1465 proc_add_orphan(child, child->p_pptr); 1466 } 1467 1468 child->p_pptr = parent; 1469 if (set_oppid) 1470 child->p_oppid = parent->p_pid; 1471 } 1472