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