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