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_LOCKED); 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 /* 217 * Exit: deallocate address space and other resources, change proc state to 218 * zombie, and unlink proc from allproc and parent's lists. Save exit status 219 * and rusage for wait(). Check for child processes and orphan them. 220 */ 221 void 222 exit1(struct thread *td, int rval, int signo) 223 { 224 struct proc *p, *nq, *q, *t; 225 struct thread *tdt; 226 ksiginfo_t *ksi, *ksi1; 227 int signal_parent; 228 229 mtx_assert(&Giant, MA_NOTOWNED); 230 KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo)); 231 TSPROCEXIT(td->td_proc->p_pid); 232 233 p = td->td_proc; 234 /* 235 * XXX in case we're rebooting we just let init die in order to 236 * work around an unsolved stack overflow seen very late during 237 * shutdown on sparc64 when the gmirror worker process exists. 238 * XXX what to do now that sparc64 is gone... remove if? 239 */ 240 if (p == initproc && rebooting == 0) { 241 printf("init died (signal %d, exit %d)\n", signo, rval); 242 panic("Going nowhere without my init!"); 243 } 244 245 /* 246 * Deref SU mp, since the thread does not return to userspace. 247 */ 248 td_softdep_cleanup(td); 249 250 /* 251 * MUST abort all other threads before proceeding past here. 252 */ 253 PROC_LOCK(p); 254 /* 255 * First check if some other thread or external request got 256 * here before us. If so, act appropriately: exit or suspend. 257 * We must ensure that stop requests are handled before we set 258 * P_WEXIT. 259 */ 260 thread_suspend_check(0); 261 while (p->p_flag & P_HADTHREADS) { 262 /* 263 * Kill off the other threads. This requires 264 * some co-operation from other parts of the kernel 265 * so it may not be instantaneous. With this state set 266 * any thread entering the kernel from userspace will 267 * thread_exit() in trap(). Any thread attempting to 268 * sleep will return immediately with EINTR or EWOULDBLOCK 269 * which will hopefully force them to back out to userland 270 * freeing resources as they go. Any thread attempting 271 * to return to userland will thread_exit() from userret(). 272 * thread_exit() will unsuspend us when the last of the 273 * other threads exits. 274 * If there is already a thread singler after resumption, 275 * calling thread_single will fail; in that case, we just 276 * re-check all suspension request, the thread should 277 * either be suspended there or exit. 278 */ 279 if (!thread_single(p, SINGLE_EXIT)) 280 /* 281 * All other activity in this process is now 282 * stopped. Threading support has been turned 283 * off. 284 */ 285 break; 286 /* 287 * Recheck for new stop or suspend requests which 288 * might appear while process lock was dropped in 289 * thread_single(). 290 */ 291 thread_suspend_check(0); 292 } 293 KASSERT(p->p_numthreads == 1, 294 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 295 racct_sub(p, RACCT_NTHR, 1); 296 297 /* Let event handler change exit status */ 298 p->p_xexit = rval; 299 p->p_xsig = signo; 300 301 /* 302 * Ignore any pending request to stop due to a stop signal. 303 * Once P_WEXIT is set, future requests will be ignored as 304 * well. 305 */ 306 p->p_flag &= ~P_STOPPED_SIG; 307 KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped")); 308 309 /* Note that we are exiting. */ 310 p->p_flag |= P_WEXIT; 311 312 /* 313 * Wait for any processes that have a hold on our vmspace to 314 * release their reference. 315 */ 316 while (p->p_lock > 0) 317 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 318 319 PROC_UNLOCK(p); 320 /* Drain the limit callout while we don't have the proc locked */ 321 callout_drain(&p->p_limco); 322 323 #ifdef AUDIT 324 /* 325 * The Sun BSM exit token contains two components: an exit status as 326 * passed to exit(), and a return value to indicate what sort of exit 327 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 328 * what the return value is. 329 */ 330 AUDIT_ARG_EXIT(rval, 0); 331 AUDIT_SYSCALL_EXIT(0, td); 332 #endif 333 334 /* Are we a task leader with peers? */ 335 if (p->p_peers != NULL && p == p->p_leader) { 336 mtx_lock(&ppeers_lock); 337 q = p->p_peers; 338 while (q != NULL) { 339 PROC_LOCK(q); 340 kern_psignal(q, SIGKILL); 341 PROC_UNLOCK(q); 342 q = q->p_peers; 343 } 344 while (p->p_peers != NULL) 345 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 346 mtx_unlock(&ppeers_lock); 347 } 348 349 itimers_exit(p); 350 351 /* 352 * Check if any loadable modules need anything done at process exit. 353 * E.g. SYSV IPC stuff. 354 * Event handler could change exit status. 355 * XXX what if one of these generates an error? 356 */ 357 EVENTHANDLER_DIRECT_INVOKE(process_exit, p); 358 359 /* 360 * If parent is waiting for us to exit or exec, 361 * P_PPWAIT is set; we will wakeup the parent below. 362 */ 363 PROC_LOCK(p); 364 stopprofclock(p); 365 p->p_ptevents = 0; 366 367 /* 368 * Stop the real interval timer. If the handler is currently 369 * executing, prevent it from rearming itself and let it finish. 370 */ 371 if (timevalisset(&p->p_realtimer.it_value) && 372 _callout_stop_safe(&p->p_itcallout, CS_EXECUTING, NULL) == 0) { 373 timevalclear(&p->p_realtimer.it_interval); 374 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 375 KASSERT(!timevalisset(&p->p_realtimer.it_value), 376 ("realtime timer is still armed")); 377 } 378 379 PROC_UNLOCK(p); 380 381 if (p->p_sysent->sv_onexit != NULL) 382 p->p_sysent->sv_onexit(p); 383 seltdfini(td); 384 385 /* 386 * Reset any sigio structures pointing to us as a result of 387 * F_SETOWN with our pid. The P_WEXIT flag interlocks with fsetown(). 388 */ 389 funsetownlst(&p->p_sigiolst); 390 391 /* 392 * Close open files and release open-file table. 393 * This may block! 394 */ 395 pdescfree(td); 396 fdescfree(td); 397 398 /* 399 * If this thread tickled GEOM, we need to wait for the giggling to 400 * stop before we return to userland 401 */ 402 if (td->td_pflags & TDP_GEOM) 403 g_waitidle(); 404 405 /* 406 * Remove ourself from our leader's peer list and wake our leader. 407 */ 408 if (p->p_leader->p_peers != NULL) { 409 mtx_lock(&ppeers_lock); 410 if (p->p_leader->p_peers != NULL) { 411 q = p->p_leader; 412 while (q->p_peers != p) 413 q = q->p_peers; 414 q->p_peers = p->p_peers; 415 wakeup(p->p_leader); 416 } 417 mtx_unlock(&ppeers_lock); 418 } 419 420 exec_free_abi_mappings(p); 421 vmspace_exit(td); 422 (void)acct_process(td); 423 424 #ifdef KTRACE 425 ktrprocexit(td); 426 #endif 427 /* 428 * Release reference to text vnode etc 429 */ 430 if (p->p_textvp != NULL) { 431 vrele(p->p_textvp); 432 p->p_textvp = NULL; 433 } 434 if (p->p_textdvp != NULL) { 435 vrele(p->p_textdvp); 436 p->p_textdvp = NULL; 437 } 438 if (p->p_binname != NULL) { 439 free(p->p_binname, M_PARGS); 440 p->p_binname = NULL; 441 } 442 443 /* 444 * Release our limits structure. 445 */ 446 lim_free(p->p_limit); 447 p->p_limit = NULL; 448 449 tidhash_remove(td); 450 451 /* 452 * Call machine-dependent code to release any 453 * machine-dependent resources other than the address space. 454 * The address space is released by "vmspace_exitfree(p)" in 455 * vm_waitproc(). 456 */ 457 cpu_exit(td); 458 459 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 460 461 /* 462 * Remove from allproc. It still sits in the hash. 463 */ 464 sx_xlock(&allproc_lock); 465 LIST_REMOVE(p, p_list); 466 467 #ifdef DDB 468 /* 469 * Used by ddb's 'ps' command to find this process via the 470 * pidhash. 471 */ 472 p->p_list.le_prev = NULL; 473 #endif 474 sx_xunlock(&allproc_lock); 475 476 sx_xlock(&proctree_lock); 477 PROC_LOCK(p); 478 p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE); 479 PROC_UNLOCK(p); 480 481 /* 482 * killjobc() might drop and re-acquire proctree_lock to 483 * revoke control tty if exiting process was a session leader. 484 */ 485 killjobc(); 486 487 /* 488 * Reparent all children processes: 489 * - traced ones to the original parent (or init if we are that parent) 490 * - the rest to init 491 */ 492 q = LIST_FIRST(&p->p_children); 493 if (q != NULL) /* only need this if any child is S_ZOMB */ 494 wakeup(q->p_reaper); 495 for (; q != NULL; q = nq) { 496 nq = LIST_NEXT(q, p_sibling); 497 ksi = ksiginfo_alloc(TRUE); 498 PROC_LOCK(q); 499 q->p_sigparent = SIGCHLD; 500 501 if ((q->p_flag & P_TRACED) == 0) { 502 proc_reparent(q, q->p_reaper, true); 503 if (q->p_state == PRS_ZOMBIE) { 504 /* 505 * Inform reaper about the reparented 506 * zombie, since wait(2) has something 507 * new to report. Guarantee queueing 508 * of the SIGCHLD signal, similar to 509 * the _exit() behaviour, by providing 510 * our ksiginfo. Ksi is freed by the 511 * signal delivery. 512 */ 513 if (q->p_ksi == NULL) { 514 ksi1 = NULL; 515 } else { 516 ksiginfo_copy(q->p_ksi, ksi); 517 ksi->ksi_flags |= KSI_INS; 518 ksi1 = ksi; 519 ksi = NULL; 520 } 521 PROC_LOCK(q->p_reaper); 522 pksignal(q->p_reaper, SIGCHLD, ksi1); 523 PROC_UNLOCK(q->p_reaper); 524 } else if (q->p_pdeathsig > 0) { 525 /* 526 * The child asked to received a signal 527 * when we exit. 528 */ 529 kern_psignal(q, q->p_pdeathsig); 530 } 531 } else { 532 /* 533 * Traced processes are killed by default 534 * since their existence means someone is 535 * screwing up. 536 */ 537 t = proc_realparent(q); 538 if (t == p) { 539 proc_reparent(q, q->p_reaper, true); 540 } else { 541 PROC_LOCK(t); 542 proc_reparent(q, t, true); 543 PROC_UNLOCK(t); 544 } 545 /* 546 * Since q was found on our children list, the 547 * proc_reparent() call moved q to the orphan 548 * list due to present P_TRACED flag. Clear 549 * orphan link for q now while q is locked. 550 */ 551 proc_clear_orphan(q); 552 q->p_flag &= ~P_TRACED; 553 q->p_flag2 &= ~P2_PTRACE_FSTP; 554 q->p_ptevents = 0; 555 p->p_xthread = NULL; 556 FOREACH_THREAD_IN_PROC(q, tdt) { 557 tdt->td_dbgflags &= ~(TDB_SUSPEND | TDB_XSIG | 558 TDB_FSTP); 559 tdt->td_xsig = 0; 560 } 561 if (kern_kill_on_dbg_exit) { 562 q->p_flag &= ~P_STOPPED_TRACE; 563 kern_psignal(q, SIGKILL); 564 } else if ((q->p_flag & (P_STOPPED_TRACE | 565 P_STOPPED_SIG)) != 0) { 566 sigqueue_delete_proc(q, SIGTRAP); 567 ptrace_unsuspend(q); 568 } 569 } 570 PROC_UNLOCK(q); 571 if (ksi != NULL) 572 ksiginfo_free(ksi); 573 } 574 575 /* 576 * Also get rid of our orphans. 577 */ 578 while ((q = LIST_FIRST(&p->p_orphans)) != NULL) { 579 PROC_LOCK(q); 580 KASSERT(q->p_oppid == p->p_pid, 581 ("orphan %p of %p has unexpected oppid %d", q, p, 582 q->p_oppid)); 583 q->p_oppid = q->p_reaper->p_pid; 584 585 /* 586 * If we are the real parent of this process 587 * but it has been reparented to a debugger, then 588 * check if it asked for a signal when we exit. 589 */ 590 if (q->p_pdeathsig > 0) 591 kern_psignal(q, q->p_pdeathsig); 592 CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid, 593 q->p_pid); 594 proc_clear_orphan(q); 595 PROC_UNLOCK(q); 596 } 597 598 #ifdef KDTRACE_HOOKS 599 if (SDT_PROBES_ENABLED()) { 600 int reason = CLD_EXITED; 601 if (WCOREDUMP(signo)) 602 reason = CLD_DUMPED; 603 else if (WIFSIGNALED(signo)) 604 reason = CLD_KILLED; 605 SDT_PROBE1(proc, , , exit, reason); 606 } 607 #endif 608 609 /* Save exit status. */ 610 PROC_LOCK(p); 611 p->p_xthread = td; 612 613 if (p->p_sysent->sv_ontdexit != NULL) 614 p->p_sysent->sv_ontdexit(td); 615 616 #ifdef KDTRACE_HOOKS 617 /* 618 * Tell the DTrace fasttrap provider about the exit if it 619 * has declared an interest. 620 */ 621 if (dtrace_fasttrap_exit) 622 dtrace_fasttrap_exit(p); 623 #endif 624 625 /* 626 * Notify interested parties of our demise. 627 */ 628 KNOTE_LOCKED(p->p_klist, NOTE_EXIT); 629 630 /* 631 * If this is a process with a descriptor, we may not need to deliver 632 * a signal to the parent. proctree_lock is held over 633 * procdesc_exit() to serialize concurrent calls to close() and 634 * exit(). 635 */ 636 signal_parent = 0; 637 if (p->p_procdesc == NULL || procdesc_exit(p)) { 638 /* 639 * Notify parent that we're gone. If parent has the 640 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN, 641 * notify process 1 instead (and hope it will handle this 642 * situation). 643 */ 644 PROC_LOCK(p->p_pptr); 645 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 646 if (p->p_pptr->p_sigacts->ps_flag & 647 (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 648 struct proc *pp; 649 650 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 651 pp = p->p_pptr; 652 PROC_UNLOCK(pp); 653 proc_reparent(p, p->p_reaper, true); 654 p->p_sigparent = SIGCHLD; 655 PROC_LOCK(p->p_pptr); 656 657 /* 658 * Notify parent, so in case he was wait(2)ing or 659 * executing waitpid(2) with our pid, he will 660 * continue. 661 */ 662 wakeup(pp); 663 } else 664 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 665 666 if (p->p_pptr == p->p_reaper || p->p_pptr == initproc) { 667 signal_parent = 1; 668 } else if (p->p_sigparent != 0) { 669 if (p->p_sigparent == SIGCHLD) { 670 signal_parent = 1; 671 } else { /* LINUX thread */ 672 signal_parent = 2; 673 } 674 } 675 } else 676 PROC_LOCK(p->p_pptr); 677 sx_xunlock(&proctree_lock); 678 679 if (signal_parent == 1) { 680 childproc_exited(p); 681 } else if (signal_parent == 2) { 682 kern_psignal(p->p_pptr, p->p_sigparent); 683 } 684 685 /* Tell the prison that we are gone. */ 686 prison_proc_free(p->p_ucred->cr_prison); 687 688 /* 689 * The state PRS_ZOMBIE prevents other proesses from sending 690 * signal to the process, to avoid memory leak, we free memory 691 * for signal queue at the time when the state is set. 692 */ 693 sigqueue_flush(&p->p_sigqueue); 694 sigqueue_flush(&td->td_sigqueue); 695 696 /* 697 * We have to wait until after acquiring all locks before 698 * changing p_state. We need to avoid all possible context 699 * switches (including ones from blocking on a mutex) while 700 * marked as a zombie. We also have to set the zombie state 701 * before we release the parent process' proc lock to avoid 702 * a lost wakeup. So, we first call wakeup, then we grab the 703 * sched lock, update the state, and release the parent process' 704 * proc lock. 705 */ 706 wakeup(p->p_pptr); 707 cv_broadcast(&p->p_pwait); 708 sched_exit(p->p_pptr, td); 709 PROC_SLOCK(p); 710 p->p_state = PRS_ZOMBIE; 711 PROC_UNLOCK(p->p_pptr); 712 713 /* 714 * Save our children's rusage information in our exit rusage. 715 */ 716 PROC_STATLOCK(p); 717 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 718 PROC_STATUNLOCK(p); 719 720 /* 721 * Make sure the scheduler takes this thread out of its tables etc. 722 * This will also release this thread's reference to the ucred. 723 * Other thread parts to release include pcb bits and such. 724 */ 725 thread_exit(); 726 } 727 728 #ifndef _SYS_SYSPROTO_H_ 729 struct abort2_args { 730 char *why; 731 int nargs; 732 void **args; 733 }; 734 #endif 735 736 int 737 sys_abort2(struct thread *td, struct abort2_args *uap) 738 { 739 void *uargs[16]; 740 void **uargsp; 741 int error, nargs; 742 743 nargs = uap->nargs; 744 if (nargs < 0 || nargs > nitems(uargs)) 745 nargs = -1; 746 uargsp = NULL; 747 if (nargs > 0) { 748 if (uap->args != NULL) { 749 error = copyin(uap->args, uargs, 750 nargs * sizeof(void *)); 751 if (error != 0) 752 nargs = -1; 753 else 754 uargsp = uargs; 755 } else 756 nargs = -1; 757 } 758 return (kern_abort2(td, uap->why, nargs, uargsp)); 759 } 760 761 /* 762 * kern_abort2() 763 * Arguments: 764 * why - user pointer to why 765 * nargs - number of arguments copied or -1 if an error occured in copying 766 * args - pointer to an array of pointers in kernel format 767 */ 768 int 769 kern_abort2(struct thread *td, const char *why, int nargs, void **uargs) 770 { 771 struct proc *p = td->td_proc; 772 struct sbuf *sb; 773 int error, i, sig; 774 775 /* 776 * Do it right now so we can log either proper call of abort2(), or 777 * note, that invalid argument was passed. 512 is big enough to 778 * handle 16 arguments' descriptions with additional comments. 779 */ 780 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 781 sbuf_clear(sb); 782 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 783 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 784 /* 785 * Since we can't return from abort2(), send SIGKILL in cases, where 786 * abort2() was called improperly 787 */ 788 sig = SIGKILL; 789 /* Prevent from DoSes from user-space. */ 790 if (nargs == -1) 791 goto out; 792 KASSERT(nargs >= 0 && nargs <= 16, ("called with too many args (%d)", 793 nargs)); 794 /* 795 * Limit size of 'reason' string to 128. Will fit even when 796 * maximal number of arguments was chosen to be logged. 797 */ 798 if (why != NULL) { 799 error = sbuf_copyin(sb, why, 128); 800 if (error < 0) 801 goto out; 802 } else { 803 sbuf_printf(sb, "(null)"); 804 } 805 if (nargs > 0) { 806 sbuf_printf(sb, "("); 807 for (i = 0;i < nargs; i++) 808 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 809 sbuf_printf(sb, ")"); 810 } 811 /* 812 * Final stage: arguments were proper, string has been 813 * successfully copied from userspace, and copying pointers 814 * from user-space succeed. 815 */ 816 sig = SIGABRT; 817 out: 818 if (sig == SIGKILL) { 819 sbuf_trim(sb); 820 sbuf_printf(sb, " (Reason text inaccessible)"); 821 } 822 sbuf_cat(sb, "\n"); 823 sbuf_finish(sb); 824 log(LOG_INFO, "%s", sbuf_data(sb)); 825 sbuf_delete(sb); 826 exit1(td, 0, sig); 827 return (0); 828 } 829 830 #ifdef COMPAT_43 831 /* 832 * The dirty work is handled by kern_wait(). 833 */ 834 int 835 owait(struct thread *td, struct owait_args *uap __unused) 836 { 837 int error, status; 838 839 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 840 if (error == 0) 841 td->td_retval[1] = status; 842 return (error); 843 } 844 #endif /* COMPAT_43 */ 845 846 /* 847 * The dirty work is handled by kern_wait(). 848 */ 849 int 850 sys_wait4(struct thread *td, struct wait4_args *uap) 851 { 852 struct rusage ru, *rup; 853 int error, status; 854 855 if (uap->rusage != NULL) 856 rup = &ru; 857 else 858 rup = NULL; 859 error = kern_wait(td, uap->pid, &status, uap->options, rup); 860 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0) 861 error = copyout(&status, uap->status, sizeof(status)); 862 if (uap->rusage != NULL && error == 0 && td->td_retval[0] != 0) 863 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 864 return (error); 865 } 866 867 int 868 sys_wait6(struct thread *td, struct wait6_args *uap) 869 { 870 struct __wrusage wru, *wrup; 871 siginfo_t si, *sip; 872 idtype_t idtype; 873 id_t id; 874 int error, status; 875 876 idtype = uap->idtype; 877 id = uap->id; 878 879 if (uap->wrusage != NULL) 880 wrup = &wru; 881 else 882 wrup = NULL; 883 884 if (uap->info != NULL) { 885 sip = &si; 886 bzero(sip, sizeof(*sip)); 887 } else 888 sip = NULL; 889 890 /* 891 * We expect all callers of wait6() to know about WEXITED and 892 * WTRAPPED. 893 */ 894 error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip); 895 896 if (uap->status != NULL && error == 0 && td->td_retval[0] != 0) 897 error = copyout(&status, uap->status, sizeof(status)); 898 if (uap->wrusage != NULL && error == 0 && td->td_retval[0] != 0) 899 error = copyout(&wru, uap->wrusage, sizeof(wru)); 900 if (uap->info != NULL && error == 0) 901 error = copyout(&si, uap->info, sizeof(si)); 902 return (error); 903 } 904 905 /* 906 * Reap the remains of a zombie process and optionally return status and 907 * rusage. Asserts and will release both the proctree_lock and the process 908 * lock as part of its work. 909 */ 910 void 911 proc_reap(struct thread *td, struct proc *p, int *status, int options) 912 { 913 struct proc *q, *t; 914 915 sx_assert(&proctree_lock, SA_XLOCKED); 916 PROC_LOCK_ASSERT(p, MA_OWNED); 917 KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); 918 919 mtx_spin_wait_unlocked(&p->p_slock); 920 921 q = td->td_proc; 922 923 if (status) 924 *status = KW_EXITCODE(p->p_xexit, p->p_xsig); 925 if (options & WNOWAIT) { 926 /* 927 * Only poll, returning the status. Caller does not wish to 928 * release the proc struct just yet. 929 */ 930 PROC_UNLOCK(p); 931 sx_xunlock(&proctree_lock); 932 return; 933 } 934 935 PROC_LOCK(q); 936 sigqueue_take(p->p_ksi); 937 PROC_UNLOCK(q); 938 939 /* 940 * If we got the child via a ptrace 'attach', we need to give it back 941 * to the old parent. 942 */ 943 if (p->p_oppid != p->p_pptr->p_pid) { 944 PROC_UNLOCK(p); 945 t = proc_realparent(p); 946 PROC_LOCK(t); 947 PROC_LOCK(p); 948 CTR2(KTR_PTRACE, 949 "wait: traced child %d moved back to parent %d", p->p_pid, 950 t->p_pid); 951 proc_reparent(p, t, false); 952 PROC_UNLOCK(p); 953 pksignal(t, SIGCHLD, p->p_ksi); 954 wakeup(t); 955 cv_broadcast(&p->p_pwait); 956 PROC_UNLOCK(t); 957 sx_xunlock(&proctree_lock); 958 return; 959 } 960 PROC_UNLOCK(p); 961 962 /* 963 * Remove other references to this process to ensure we have an 964 * exclusive reference. 965 */ 966 sx_xlock(PIDHASHLOCK(p->p_pid)); 967 LIST_REMOVE(p, p_hash); 968 sx_xunlock(PIDHASHLOCK(p->p_pid)); 969 LIST_REMOVE(p, p_sibling); 970 reaper_abandon_children(p, true); 971 reaper_clear(p); 972 PROC_LOCK(p); 973 proc_clear_orphan(p); 974 PROC_UNLOCK(p); 975 leavepgrp(p); 976 if (p->p_procdesc != NULL) 977 procdesc_reap(p); 978 sx_xunlock(&proctree_lock); 979 980 proc_id_clear(PROC_ID_PID, p->p_pid); 981 982 PROC_LOCK(p); 983 knlist_detach(p->p_klist); 984 p->p_klist = NULL; 985 PROC_UNLOCK(p); 986 987 /* 988 * Removal from allproc list and process group list paired with 989 * PROC_LOCK which was executed during that time should guarantee 990 * nothing can reach this process anymore. As such further locking 991 * is unnecessary. 992 */ 993 p->p_xexit = p->p_xsig = 0; /* XXX: why? */ 994 995 PROC_LOCK(q); 996 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux); 997 PROC_UNLOCK(q); 998 999 /* 1000 * Decrement the count of procs running with this uid. 1001 */ 1002 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 1003 1004 /* 1005 * Destroy resource accounting information associated with the process. 1006 */ 1007 #ifdef RACCT 1008 if (racct_enable) { 1009 PROC_LOCK(p); 1010 racct_sub(p, RACCT_NPROC, 1); 1011 PROC_UNLOCK(p); 1012 } 1013 #endif 1014 racct_proc_exit(p); 1015 1016 /* 1017 * Free credentials, arguments, and sigacts. 1018 */ 1019 proc_unset_cred(p); 1020 pargs_drop(p->p_args); 1021 p->p_args = NULL; 1022 sigacts_free(p->p_sigacts); 1023 p->p_sigacts = NULL; 1024 1025 /* 1026 * Do any thread-system specific cleanups. 1027 */ 1028 thread_wait(p); 1029 1030 /* 1031 * Give vm and machine-dependent layer a chance to free anything that 1032 * cpu_exit couldn't release while still running in process context. 1033 */ 1034 vm_waitproc(p); 1035 #ifdef MAC 1036 mac_proc_destroy(p); 1037 #endif 1038 1039 KASSERT(FIRST_THREAD_IN_PROC(p), 1040 ("proc_reap: no residual thread!")); 1041 uma_zfree(proc_zone, p); 1042 atomic_add_int(&nprocs, -1); 1043 } 1044 1045 static int 1046 proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id, 1047 int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo, 1048 int check_only) 1049 { 1050 struct rusage *rup; 1051 1052 sx_assert(&proctree_lock, SA_XLOCKED); 1053 1054 PROC_LOCK(p); 1055 1056 switch (idtype) { 1057 case P_ALL: 1058 if (p->p_procdesc == NULL || 1059 (p->p_pptr == td->td_proc && 1060 (p->p_flag & P_TRACED) != 0)) { 1061 break; 1062 } 1063 1064 PROC_UNLOCK(p); 1065 return (0); 1066 case P_PID: 1067 if (p->p_pid != (pid_t)id) { 1068 PROC_UNLOCK(p); 1069 return (0); 1070 } 1071 break; 1072 case P_PGID: 1073 if (p->p_pgid != (pid_t)id) { 1074 PROC_UNLOCK(p); 1075 return (0); 1076 } 1077 break; 1078 case P_SID: 1079 if (p->p_session->s_sid != (pid_t)id) { 1080 PROC_UNLOCK(p); 1081 return (0); 1082 } 1083 break; 1084 case P_UID: 1085 if (p->p_ucred->cr_uid != (uid_t)id) { 1086 PROC_UNLOCK(p); 1087 return (0); 1088 } 1089 break; 1090 case P_GID: 1091 if (p->p_ucred->cr_gid != (gid_t)id) { 1092 PROC_UNLOCK(p); 1093 return (0); 1094 } 1095 break; 1096 case P_JAILID: 1097 if (p->p_ucred->cr_prison->pr_id != (int)id) { 1098 PROC_UNLOCK(p); 1099 return (0); 1100 } 1101 break; 1102 /* 1103 * It seems that the thread structures get zeroed out 1104 * at process exit. This makes it impossible to 1105 * support P_SETID, P_CID or P_CPUID. 1106 */ 1107 default: 1108 PROC_UNLOCK(p); 1109 return (0); 1110 } 1111 1112 if (p_canwait(td, p)) { 1113 PROC_UNLOCK(p); 1114 return (0); 1115 } 1116 1117 if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) { 1118 PROC_UNLOCK(p); 1119 return (0); 1120 } 1121 1122 /* 1123 * This special case handles a kthread spawned by linux_clone 1124 * (see linux_misc.c). The linux_wait4 and linux_waitpid 1125 * functions need to be able to distinguish between waiting 1126 * on a process and waiting on a thread. It is a thread if 1127 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 1128 * signifies we want to wait for threads and not processes. 1129 */ 1130 if ((p->p_sigparent != SIGCHLD) ^ 1131 ((options & WLINUXCLONE) != 0)) { 1132 PROC_UNLOCK(p); 1133 return (0); 1134 } 1135 1136 if (siginfo != NULL) { 1137 bzero(siginfo, sizeof(*siginfo)); 1138 siginfo->si_errno = 0; 1139 1140 /* 1141 * SUSv4 requires that the si_signo value is always 1142 * SIGCHLD. Obey it despite the rfork(2) interface 1143 * allows to request other signal for child exit 1144 * notification. 1145 */ 1146 siginfo->si_signo = SIGCHLD; 1147 1148 /* 1149 * This is still a rough estimate. We will fix the 1150 * cases TRAPPED, STOPPED, and CONTINUED later. 1151 */ 1152 if (WCOREDUMP(p->p_xsig)) { 1153 siginfo->si_code = CLD_DUMPED; 1154 siginfo->si_status = WTERMSIG(p->p_xsig); 1155 } else if (WIFSIGNALED(p->p_xsig)) { 1156 siginfo->si_code = CLD_KILLED; 1157 siginfo->si_status = WTERMSIG(p->p_xsig); 1158 } else { 1159 siginfo->si_code = CLD_EXITED; 1160 siginfo->si_status = p->p_xexit; 1161 } 1162 1163 siginfo->si_pid = p->p_pid; 1164 siginfo->si_uid = p->p_ucred->cr_uid; 1165 1166 /* 1167 * The si_addr field would be useful additional 1168 * detail, but apparently the PC value may be lost 1169 * when we reach this point. bzero() above sets 1170 * siginfo->si_addr to NULL. 1171 */ 1172 } 1173 1174 /* 1175 * There should be no reason to limit resources usage info to 1176 * exited processes only. A snapshot about any resources used 1177 * by a stopped process may be exactly what is needed. 1178 */ 1179 if (wrusage != NULL) { 1180 rup = &wrusage->wru_self; 1181 *rup = p->p_ru; 1182 PROC_STATLOCK(p); 1183 calcru(p, &rup->ru_utime, &rup->ru_stime); 1184 PROC_STATUNLOCK(p); 1185 1186 rup = &wrusage->wru_children; 1187 *rup = p->p_stats->p_cru; 1188 calccru(p, &rup->ru_utime, &rup->ru_stime); 1189 } 1190 1191 if (p->p_state == PRS_ZOMBIE && !check_only) { 1192 proc_reap(td, p, status, options); 1193 return (-1); 1194 } 1195 return (1); 1196 } 1197 1198 int 1199 kern_wait(struct thread *td, pid_t pid, int *status, int options, 1200 struct rusage *rusage) 1201 { 1202 struct __wrusage wru, *wrup; 1203 idtype_t idtype; 1204 id_t id; 1205 int ret; 1206 1207 /* 1208 * Translate the special pid values into the (idtype, pid) 1209 * pair for kern_wait6. The WAIT_MYPGRP case is handled by 1210 * kern_wait6() on its own. 1211 */ 1212 if (pid == WAIT_ANY) { 1213 idtype = P_ALL; 1214 id = 0; 1215 } else if (pid < 0) { 1216 idtype = P_PGID; 1217 id = (id_t)-pid; 1218 } else { 1219 idtype = P_PID; 1220 id = (id_t)pid; 1221 } 1222 1223 if (rusage != NULL) 1224 wrup = &wru; 1225 else 1226 wrup = NULL; 1227 1228 /* 1229 * For backward compatibility we implicitly add flags WEXITED 1230 * and WTRAPPED here. 1231 */ 1232 options |= WEXITED | WTRAPPED; 1233 ret = kern_wait6(td, idtype, id, status, options, wrup, NULL); 1234 if (rusage != NULL) 1235 *rusage = wru.wru_self; 1236 return (ret); 1237 } 1238 1239 static void 1240 report_alive_proc(struct thread *td, struct proc *p, siginfo_t *siginfo, 1241 int *status, int options, int si_code) 1242 { 1243 bool cont; 1244 1245 PROC_LOCK_ASSERT(p, MA_OWNED); 1246 sx_assert(&proctree_lock, SA_XLOCKED); 1247 MPASS(si_code == CLD_TRAPPED || si_code == CLD_STOPPED || 1248 si_code == CLD_CONTINUED); 1249 1250 cont = si_code == CLD_CONTINUED; 1251 if ((options & WNOWAIT) == 0) { 1252 if (cont) 1253 p->p_flag &= ~P_CONTINUED; 1254 else 1255 p->p_flag |= P_WAITED; 1256 if (kern_wait_dequeue_sigchld && 1257 (td->td_proc->p_sysent->sv_flags & SV_SIG_WAITNDQ) == 0) { 1258 PROC_LOCK(td->td_proc); 1259 sigqueue_take(p->p_ksi); 1260 PROC_UNLOCK(td->td_proc); 1261 } 1262 } 1263 sx_xunlock(&proctree_lock); 1264 if (siginfo != NULL) { 1265 siginfo->si_code = si_code; 1266 siginfo->si_status = cont ? SIGCONT : p->p_xsig; 1267 } 1268 if (status != NULL) 1269 *status = cont ? SIGCONT : W_STOPCODE(p->p_xsig); 1270 PROC_UNLOCK(p); 1271 td->td_retval[0] = p->p_pid; 1272 } 1273 1274 int 1275 kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status, 1276 int options, struct __wrusage *wrusage, siginfo_t *siginfo) 1277 { 1278 struct proc *p, *q; 1279 pid_t pid; 1280 int error, nfound, ret; 1281 bool report; 1282 1283 AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */ 1284 AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */ 1285 AUDIT_ARG_VALUE(options); 1286 1287 q = td->td_proc; 1288 1289 if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { 1290 PROC_LOCK(q); 1291 id = (id_t)q->p_pgid; 1292 PROC_UNLOCK(q); 1293 idtype = P_PGID; 1294 } 1295 1296 /* If we don't know the option, just return. */ 1297 if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT | 1298 WEXITED | WTRAPPED | WLINUXCLONE)) != 0) 1299 return (EINVAL); 1300 if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) { 1301 /* 1302 * We will be unable to find any matching processes, 1303 * because there are no known events to look for. 1304 * Prefer to return error instead of blocking 1305 * indefinitely. 1306 */ 1307 return (EINVAL); 1308 } 1309 1310 loop: 1311 if (q->p_flag & P_STATCHILD) { 1312 PROC_LOCK(q); 1313 q->p_flag &= ~P_STATCHILD; 1314 PROC_UNLOCK(q); 1315 } 1316 sx_xlock(&proctree_lock); 1317 loop_locked: 1318 nfound = 0; 1319 LIST_FOREACH(p, &q->p_children, p_sibling) { 1320 pid = p->p_pid; 1321 ret = proc_to_reap(td, p, idtype, id, status, options, 1322 wrusage, siginfo, 0); 1323 if (ret == 0) 1324 continue; 1325 else if (ret != 1) { 1326 td->td_retval[0] = pid; 1327 return (0); 1328 } 1329 1330 nfound++; 1331 PROC_LOCK_ASSERT(p, MA_OWNED); 1332 1333 if ((options & WTRAPPED) != 0 && 1334 (p->p_flag & P_TRACED) != 0) { 1335 PROC_SLOCK(p); 1336 report = 1337 ((p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) && 1338 p->p_suspcount == p->p_numthreads && 1339 (p->p_flag & P_WAITED) == 0); 1340 PROC_SUNLOCK(p); 1341 if (report) { 1342 CTR4(KTR_PTRACE, 1343 "wait: returning trapped pid %d status %#x " 1344 "(xstat %d) xthread %d", 1345 p->p_pid, W_STOPCODE(p->p_xsig), p->p_xsig, 1346 p->p_xthread != NULL ? 1347 p->p_xthread->td_tid : -1); 1348 report_alive_proc(td, p, siginfo, status, 1349 options, CLD_TRAPPED); 1350 return (0); 1351 } 1352 } 1353 if ((options & WUNTRACED) != 0 && 1354 (p->p_flag & P_STOPPED_SIG) != 0) { 1355 PROC_SLOCK(p); 1356 report = (p->p_suspcount == p->p_numthreads && 1357 ((p->p_flag & P_WAITED) == 0)); 1358 PROC_SUNLOCK(p); 1359 if (report) { 1360 report_alive_proc(td, p, siginfo, status, 1361 options, CLD_STOPPED); 1362 return (0); 1363 } 1364 } 1365 if ((options & WCONTINUED) != 0 && 1366 (p->p_flag & P_CONTINUED) != 0) { 1367 report_alive_proc(td, p, siginfo, status, options, 1368 CLD_CONTINUED); 1369 return (0); 1370 } 1371 PROC_UNLOCK(p); 1372 } 1373 1374 /* 1375 * Look in the orphans list too, to allow the parent to 1376 * collect it's child exit status even if child is being 1377 * debugged. 1378 * 1379 * Debugger detaches from the parent upon successful 1380 * switch-over from parent to child. At this point due to 1381 * re-parenting the parent loses the child to debugger and a 1382 * wait4(2) call would report that it has no children to wait 1383 * for. By maintaining a list of orphans we allow the parent 1384 * to successfully wait until the child becomes a zombie. 1385 */ 1386 if (nfound == 0) { 1387 LIST_FOREACH(p, &q->p_orphans, p_orphan) { 1388 ret = proc_to_reap(td, p, idtype, id, NULL, options, 1389 NULL, NULL, 1); 1390 if (ret != 0) { 1391 KASSERT(ret != -1, ("reaped an orphan (pid %d)", 1392 (int)td->td_retval[0])); 1393 PROC_UNLOCK(p); 1394 nfound++; 1395 break; 1396 } 1397 } 1398 } 1399 if (nfound == 0) { 1400 sx_xunlock(&proctree_lock); 1401 return (ECHILD); 1402 } 1403 if (options & WNOHANG) { 1404 sx_xunlock(&proctree_lock); 1405 td->td_retval[0] = 0; 1406 return (0); 1407 } 1408 PROC_LOCK(q); 1409 if (q->p_flag & P_STATCHILD) { 1410 q->p_flag &= ~P_STATCHILD; 1411 PROC_UNLOCK(q); 1412 goto loop_locked; 1413 } 1414 sx_xunlock(&proctree_lock); 1415 error = msleep(q, &q->p_mtx, PWAIT | PCATCH | PDROP, "wait", 0); 1416 if (error) 1417 return (error); 1418 goto loop; 1419 } 1420 1421 void 1422 proc_add_orphan(struct proc *child, struct proc *parent) 1423 { 1424 1425 sx_assert(&proctree_lock, SX_XLOCKED); 1426 KASSERT((child->p_flag & P_TRACED) != 0, 1427 ("proc_add_orphan: not traced")); 1428 1429 if (LIST_EMPTY(&parent->p_orphans)) { 1430 child->p_treeflag |= P_TREE_FIRST_ORPHAN; 1431 LIST_INSERT_HEAD(&parent->p_orphans, child, p_orphan); 1432 } else { 1433 LIST_INSERT_AFTER(LIST_FIRST(&parent->p_orphans), 1434 child, p_orphan); 1435 } 1436 child->p_treeflag |= P_TREE_ORPHANED; 1437 } 1438 1439 /* 1440 * Make process 'parent' the new parent of process 'child'. 1441 * Must be called with an exclusive hold of proctree lock. 1442 */ 1443 void 1444 proc_reparent(struct proc *child, struct proc *parent, bool set_oppid) 1445 { 1446 1447 sx_assert(&proctree_lock, SX_XLOCKED); 1448 PROC_LOCK_ASSERT(child, MA_OWNED); 1449 if (child->p_pptr == parent) 1450 return; 1451 1452 PROC_LOCK(child->p_pptr); 1453 sigqueue_take(child->p_ksi); 1454 PROC_UNLOCK(child->p_pptr); 1455 LIST_REMOVE(child, p_sibling); 1456 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 1457 1458 proc_clear_orphan(child); 1459 if ((child->p_flag & P_TRACED) != 0) { 1460 proc_add_orphan(child, child->p_pptr); 1461 } 1462 1463 child->p_pptr = parent; 1464 if (set_oppid) 1465 child->p_oppid = parent->p_pid; 1466 } 1467