Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c
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1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_compat.h" 41 #include "opt_kdtrace.h" 42 #include "opt_ktrace.h" 43 #include "opt_mac.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/sysproto.h> 48 #include <sys/eventhandler.h> 49 #include <sys/kernel.h> 50 #include <sys/malloc.h> 51 #include <sys/lock.h> 52 #include <sys/mutex.h> 53 #include <sys/proc.h> 54 #include <sys/pioctl.h> 55 #include <sys/jail.h> 56 #include <sys/tty.h> 57 #include <sys/wait.h> 58 #include <sys/vmmeter.h> 59 #include <sys/vnode.h> 60 #include <sys/resourcevar.h> 61 #include <sys/sbuf.h> 62 #include <sys/signalvar.h> 63 #include <sys/sched.h> 64 #include <sys/sx.h> 65 #include <sys/syscallsubr.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 #ifdef KTRACE 74 #include <sys/ktrace.h> 75 #endif 76 77 #include <security/audit/audit.h> 78 #include <security/mac/mac_framework.h> 79 80 #include <vm/vm.h> 81 #include <vm/vm_extern.h> 82 #include <vm/vm_param.h> 83 #include <vm/pmap.h> 84 #include <vm/vm_map.h> 85 #include <vm/vm_page.h> 86 #include <vm/uma.h> 87 88 #ifdef KDTRACE_HOOKS 89 #include <sys/dtrace_bsd.h> 90 dtrace_execexit_func_t dtrace_fasttrap_exit; 91 #endif 92 93 SDT_PROVIDER_DECLARE(proc); 94 SDT_PROBE_DEFINE(proc, kernel, , exit); 95 SDT_PROBE_ARGTYPE(proc, kernel, , exit, 0, "int"); 96 97 /* Required to be non-static for SysVR4 emulator */ 98 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 99 100 /* Hook for NFS teardown procedure. */ 101 void (*nlminfo_release_p)(struct proc *p); 102 103 /* 104 * exit -- death of process. 105 */ 106 void 107 sys_exit(struct thread *td, struct sys_exit_args *uap) 108 { 109 110 exit1(td, W_EXITCODE(uap->rval, 0)); 111 /* NOTREACHED */ 112 } 113 114 /* 115 * Exit: deallocate address space and other resources, change proc state to 116 * zombie, and unlink proc from allproc and parent's lists. Save exit status 117 * and rusage for wait(). Check for child processes and orphan them. 118 */ 119 void 120 exit1(struct thread *td, int rv) 121 { 122 struct proc *p, *nq, *q; 123 struct tty *tp; 124 struct vnode *ttyvp; 125 struct vnode *vtmp; 126 #ifdef KTRACE 127 struct vnode *tracevp; 128 struct ucred *tracecred; 129 #endif 130 struct plimit *plim; 131 int locked; 132 133 /* 134 * Drop Giant if caller has it. Eventually we should warn about 135 * being called with Giant held. 136 */ 137 while (mtx_owned(&Giant)) 138 mtx_unlock(&Giant); 139 140 p = td->td_proc; 141 if (p == initproc) { 142 printf("init died (signal %d, exit %d)\n", 143 WTERMSIG(rv), WEXITSTATUS(rv)); 144 panic("Going nowhere without my init!"); 145 } 146 147 /* 148 * MUST abort all other threads before proceeding past here. 149 */ 150 PROC_LOCK(p); 151 if (p->p_flag & P_HADTHREADS) { 152 retry: 153 /* 154 * First check if some other thread got here before us.. 155 * if so, act apropriatly, (exit or suspend); 156 */ 157 thread_suspend_check(0); 158 159 /* 160 * Kill off the other threads. This requires 161 * some co-operation from other parts of the kernel 162 * so it may not be instantaneous. With this state set 163 * any thread entering the kernel from userspace will 164 * thread_exit() in trap(). Any thread attempting to 165 * sleep will return immediately with EINTR or EWOULDBLOCK 166 * which will hopefully force them to back out to userland 167 * freeing resources as they go. Any thread attempting 168 * to return to userland will thread_exit() from userret(). 169 * thread_exit() will unsuspend us when the last of the 170 * other threads exits. 171 * If there is already a thread singler after resumption, 172 * calling thread_single will fail; in that case, we just 173 * re-check all suspension request, the thread should 174 * either be suspended there or exit. 175 */ 176 if (thread_single(SINGLE_EXIT)) 177 goto retry; 178 179 /* 180 * All other activity in this process is now stopped. 181 * Threading support has been turned off. 182 */ 183 } 184 KASSERT(p->p_numthreads == 1, 185 ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); 186 /* 187 * Wakeup anyone in procfs' PIOCWAIT. They should have a hold 188 * on our vmspace, so we should block below until they have 189 * released their reference to us. Note that if they have 190 * requested S_EXIT stops we will block here until they ack 191 * via PIOCCONT. 192 */ 193 _STOPEVENT(p, S_EXIT, rv); 194 195 /* 196 * Note that we are exiting and do another wakeup of anyone in 197 * PIOCWAIT in case they aren't listening for S_EXIT stops or 198 * decided to wait again after we told them we are exiting. 199 */ 200 p->p_flag |= P_WEXIT; 201 wakeup(&p->p_stype); 202 203 /* 204 * Wait for any processes that have a hold on our vmspace to 205 * release their reference. 206 */ 207 while (p->p_lock > 0) 208 msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); 209 210 PROC_UNLOCK(p); 211 /* Drain the limit callout while we don't have the proc locked */ 212 callout_drain(&p->p_limco); 213 214 #ifdef AUDIT 215 /* 216 * The Sun BSM exit token contains two components: an exit status as 217 * passed to exit(), and a return value to indicate what sort of exit 218 * it was. The exit status is WEXITSTATUS(rv), but it's not clear 219 * what the return value is. 220 */ 221 AUDIT_ARG(exit, WEXITSTATUS(rv), 0); 222 AUDIT_SYSCALL_EXIT(0, td); 223 #endif 224 225 /* Are we a task leader? */ 226 if (p == p->p_leader) { 227 mtx_lock(&ppeers_lock); 228 q = p->p_peers; 229 while (q != NULL) { 230 PROC_LOCK(q); 231 psignal(q, SIGKILL); 232 PROC_UNLOCK(q); 233 q = q->p_peers; 234 } 235 while (p->p_peers != NULL) 236 msleep(p, &ppeers_lock, PWAIT, "exit1", 0); 237 mtx_unlock(&ppeers_lock); 238 } 239 240 /* 241 * Check if any loadable modules need anything done at process exit. 242 * E.g. SYSV IPC stuff 243 * XXX what if one of these generates an error? 244 */ 245 EVENTHANDLER_INVOKE(process_exit, p); 246 247 /* 248 * If parent is waiting for us to exit or exec, 249 * P_PPWAIT is set; we will wakeup the parent below. 250 */ 251 PROC_LOCK(p); 252 stopprofclock(p); 253 p->p_flag &= ~(P_TRACED | P_PPWAIT); 254 255 /* 256 * Stop the real interval timer. If the handler is currently 257 * executing, prevent it from rearming itself and let it finish. 258 */ 259 if (timevalisset(&p->p_realtimer.it_value) && 260 callout_stop(&p->p_itcallout) == 0) { 261 timevalclear(&p->p_realtimer.it_interval); 262 msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); 263 KASSERT(!timevalisset(&p->p_realtimer.it_value), 264 ("realtime timer is still armed")); 265 } 266 PROC_UNLOCK(p); 267 268 /* 269 * Reset any sigio structures pointing to us as a result of 270 * F_SETOWN with our pid. 271 */ 272 funsetownlst(&p->p_sigiolst); 273 274 /* 275 * If this process has an nlminfo data area (for lockd), release it 276 */ 277 if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) 278 (*nlminfo_release_p)(p); 279 280 /* 281 * Close open files and release open-file table. 282 * This may block! 283 */ 284 fdfree(td); 285 286 /* 287 * If this thread tickled GEOM, we need to wait for the giggling to 288 * stop before we return to userland 289 */ 290 if (td->td_pflags & TDP_GEOM) 291 g_waitidle(); 292 293 /* 294 * Remove ourself from our leader's peer list and wake our leader. 295 */ 296 mtx_lock(&ppeers_lock); 297 if (p->p_leader->p_peers) { 298 q = p->p_leader; 299 while (q->p_peers != p) 300 q = q->p_peers; 301 q->p_peers = p->p_peers; 302 wakeup(p->p_leader); 303 } 304 mtx_unlock(&ppeers_lock); 305 306 vmspace_exit(td); 307 308 mtx_lock(&Giant); /* XXX TTY */ 309 sx_xlock(&proctree_lock); 310 if (SESS_LEADER(p)) { 311 struct session *sp; 312 313 sp = p->p_session; 314 if (sp->s_ttyvp) { 315 /* 316 * Controlling process. 317 * Signal foreground pgrp, 318 * drain controlling terminal 319 * and revoke access to controlling terminal. 320 */ 321 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 322 tp = sp->s_ttyp; 323 if (sp->s_ttyp->t_pgrp) { 324 PGRP_LOCK(sp->s_ttyp->t_pgrp); 325 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 326 PGRP_UNLOCK(sp->s_ttyp->t_pgrp); 327 } 328 /* XXX tp should be locked. */ 329 sx_xunlock(&proctree_lock); 330 (void) ttywait(tp); 331 sx_xlock(&proctree_lock); 332 /* 333 * The tty could have been revoked 334 * if we blocked. 335 */ 336 if (sp->s_ttyvp) { 337 ttyvp = sp->s_ttyvp; 338 SESS_LOCK(p->p_session); 339 sp->s_ttyvp = NULL; 340 SESS_UNLOCK(p->p_session); 341 sx_xunlock(&proctree_lock); 342 VOP_LOCK(ttyvp, LK_EXCLUSIVE, td); 343 VOP_REVOKE(ttyvp, REVOKEALL); 344 vput(ttyvp); 345 sx_xlock(&proctree_lock); 346 } 347 } 348 if (sp->s_ttyvp) { 349 ttyvp = sp->s_ttyvp; 350 SESS_LOCK(p->p_session); 351 sp->s_ttyvp = NULL; 352 SESS_UNLOCK(p->p_session); 353 vrele(ttyvp); 354 } 355 /* 356 * s_ttyp is not zero'd; we use this to indicate 357 * that the session once had a controlling terminal. 358 * (for logging and informational purposes) 359 */ 360 } 361 SESS_LOCK(p->p_session); 362 sp->s_leader = NULL; 363 SESS_UNLOCK(p->p_session); 364 } 365 fixjobc(p, p->p_pgrp, 0); 366 sx_xunlock(&proctree_lock); 367 (void)acct_process(td); 368 mtx_unlock(&Giant); 369 #ifdef KTRACE 370 /* 371 * Disable tracing, then drain any pending records and release 372 * the trace file. 373 */ 374 if (p->p_traceflag != 0) { 375 PROC_LOCK(p); 376 mtx_lock(&ktrace_mtx); 377 p->p_traceflag = 0; 378 mtx_unlock(&ktrace_mtx); 379 PROC_UNLOCK(p); 380 ktrprocexit(td); 381 PROC_LOCK(p); 382 mtx_lock(&ktrace_mtx); 383 tracevp = p->p_tracevp; 384 p->p_tracevp = NULL; 385 tracecred = p->p_tracecred; 386 p->p_tracecred = NULL; 387 mtx_unlock(&ktrace_mtx); 388 PROC_UNLOCK(p); 389 if (tracevp != NULL) { 390 locked = VFS_LOCK_GIANT(tracevp->v_mount); 391 vrele(tracevp); 392 VFS_UNLOCK_GIANT(locked); 393 } 394 if (tracecred != NULL) 395 crfree(tracecred); 396 } 397 #endif 398 /* 399 * Release reference to text vnode 400 */ 401 if ((vtmp = p->p_textvp) != NULL) { 402 p->p_textvp = NULL; 403 locked = VFS_LOCK_GIANT(vtmp->v_mount); 404 vrele(vtmp); 405 VFS_UNLOCK_GIANT(locked); 406 } 407 408 /* 409 * Release our limits structure. 410 */ 411 PROC_LOCK(p); 412 plim = p->p_limit; 413 p->p_limit = NULL; 414 PROC_UNLOCK(p); 415 lim_free(plim); 416 417 /* 418 * Remove proc from allproc queue and pidhash chain. 419 * Place onto zombproc. Unlink from parent's child list. 420 */ 421 sx_xlock(&allproc_lock); 422 LIST_REMOVE(p, p_list); 423 LIST_INSERT_HEAD(&zombproc, p, p_list); 424 LIST_REMOVE(p, p_hash); 425 sx_xunlock(&allproc_lock); 426 427 /* 428 * Call machine-dependent code to release any 429 * machine-dependent resources other than the address space. 430 * The address space is released by "vmspace_exitfree(p)" in 431 * vm_waitproc(). 432 */ 433 cpu_exit(td); 434 435 WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); 436 437 /* 438 * Reparent all of our children to init. 439 */ 440 sx_xlock(&proctree_lock); 441 q = LIST_FIRST(&p->p_children); 442 if (q != NULL) /* only need this if any child is S_ZOMB */ 443 wakeup(initproc); 444 for (; q != NULL; q = nq) { 445 nq = LIST_NEXT(q, p_sibling); 446 PROC_LOCK(q); 447 proc_reparent(q, initproc); 448 q->p_sigparent = SIGCHLD; 449 /* 450 * Traced processes are killed 451 * since their existence means someone is screwing up. 452 */ 453 if (q->p_flag & P_TRACED) { 454 q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); 455 psignal(q, SIGKILL); 456 } 457 PROC_UNLOCK(q); 458 } 459 460 /* Save exit status. */ 461 PROC_LOCK(p); 462 p->p_xstat = rv; 463 p->p_xthread = td; 464 465 /* In case we are jailed tell the prison that we are gone. */ 466 if (jailed(p->p_ucred)) 467 prison_proc_free(p->p_ucred->cr_prison); 468 469 #ifdef KDTRACE_HOOKS 470 /* 471 * Tell the DTrace fasttrap provider about the exit if it 472 * has declared an interest. 473 */ 474 if (dtrace_fasttrap_exit) 475 dtrace_fasttrap_exit(p); 476 #endif 477 478 /* 479 * Notify interested parties of our demise. 480 */ 481 KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); 482 483 #ifdef KDTRACE_HOOKS 484 int reason = CLD_EXITED; 485 if (WCOREDUMP(rv)) 486 reason = CLD_DUMPED; 487 else if (WIFSIGNALED(rv)) 488 reason = CLD_KILLED; 489 SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); 490 #endif 491 /* 492 * Just delete all entries in the p_klist. At this point we won't 493 * report any more events, and there are nasty race conditions that 494 * can beat us if we don't. 495 */ 496 knlist_clear(&p->p_klist, 1); 497 498 /* 499 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 500 * flag set, or if the handler is set to SIG_IGN, notify process 501 * 1 instead (and hope it will handle this situation). 502 */ 503 PROC_LOCK(p->p_pptr); 504 mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); 505 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { 506 struct proc *pp; 507 508 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 509 pp = p->p_pptr; 510 PROC_UNLOCK(pp); 511 proc_reparent(p, initproc); 512 p->p_sigparent = SIGCHLD; 513 PROC_LOCK(p->p_pptr); 514 /* 515 * If this was the last child of our parent, notify 516 * parent, so in case he was wait(2)ing, he will 517 * continue. 518 */ 519 if (LIST_EMPTY(&pp->p_children)) 520 wakeup(pp); 521 } else 522 mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); 523 524 if (p->p_pptr == initproc) 525 psignal(p->p_pptr, SIGCHLD); 526 else if (p->p_sigparent != 0) { 527 if (p->p_sigparent == SIGCHLD) 528 childproc_exited(p); 529 else /* LINUX thread */ 530 psignal(p->p_pptr, p->p_sigparent); 531 } 532 sx_xunlock(&proctree_lock); 533 534 /* 535 * The state PRS_ZOMBIE prevents other proesses from sending 536 * signal to the process, to avoid memory leak, we free memory 537 * for signal queue at the time when the state is set. 538 */ 539 sigqueue_flush(&p->p_sigqueue); 540 sigqueue_flush(&td->td_sigqueue); 541 542 /* 543 * We have to wait until after acquiring all locks before 544 * changing p_state. We need to avoid all possible context 545 * switches (including ones from blocking on a mutex) while 546 * marked as a zombie. We also have to set the zombie state 547 * before we release the parent process' proc lock to avoid 548 * a lost wakeup. So, we first call wakeup, then we grab the 549 * sched lock, update the state, and release the parent process' 550 * proc lock. 551 */ 552 wakeup(p->p_pptr); 553 PROC_SLOCK(p->p_pptr); 554 sched_exit(p->p_pptr, td); 555 PROC_SUNLOCK(p->p_pptr); 556 PROC_SLOCK(p); 557 p->p_state = PRS_ZOMBIE; 558 PROC_UNLOCK(p->p_pptr); 559 560 /* 561 * Hopefully no one will try to deliver a signal to the process this 562 * late in the game. 563 */ 564 knlist_destroy(&p->p_klist); 565 566 /* 567 * Save our children's rusage information in our exit rusage. 568 */ 569 ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); 570 571 /* 572 * Make sure the scheduler takes this thread out of its tables etc. 573 * This will also release this thread's reference to the ucred. 574 * Other thread parts to release include pcb bits and such. 575 */ 576 thread_exit(); 577 } 578 579 580 #ifndef _SYS_SYSPROTO_H_ 581 struct abort2_args { 582 char *why; 583 int nargs; 584 void **args; 585 }; 586 #endif 587 588 int 589 abort2(struct thread *td, struct abort2_args *uap) 590 { 591 struct proc *p = td->td_proc; 592 struct sbuf *sb; 593 void *uargs[16]; 594 int error, i, sig; 595 596 error = 0; /* satisfy compiler */ 597 598 /* 599 * Do it right now so we can log either proper call of abort2(), or 600 * note, that invalid argument was passed. 512 is big enough to 601 * handle 16 arguments' descriptions with additional comments. 602 */ 603 sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); 604 sbuf_clear(sb); 605 sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", 606 p->p_comm, p->p_pid, td->td_ucred->cr_uid); 607 /* 608 * Since we can't return from abort2(), send SIGKILL in cases, where 609 * abort2() was called improperly 610 */ 611 sig = SIGKILL; 612 /* Prevent from DoSes from user-space. */ 613 if (uap->nargs < 0 || uap->nargs > 16) 614 goto out; 615 if (uap->nargs > 0) { 616 if (uap->args == NULL) 617 goto out; 618 error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); 619 if (error != 0) 620 goto out; 621 } 622 /* 623 * Limit size of 'reason' string to 128. Will fit even when 624 * maximal number of arguments was chosen to be logged. 625 */ 626 if (uap->why != NULL) { 627 error = sbuf_copyin(sb, uap->why, 128); 628 if (error < 0) 629 goto out; 630 } else { 631 sbuf_printf(sb, "(null)"); 632 } 633 if (uap->nargs > 0) { 634 sbuf_printf(sb, "("); 635 for (i = 0;i < uap->nargs; i++) 636 sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); 637 sbuf_printf(sb, ")"); 638 } 639 /* 640 * Final stage: arguments were proper, string has been 641 * successfully copied from userspace, and copying pointers 642 * from user-space succeed. 643 */ 644 sig = SIGABRT; 645 out: 646 if (sig == SIGKILL) { 647 sbuf_trim(sb); 648 sbuf_printf(sb, " (Reason text inaccessible)"); 649 } 650 sbuf_cat(sb, "\n"); 651 sbuf_finish(sb); 652 log(LOG_INFO, "%s", sbuf_data(sb)); 653 sbuf_delete(sb); 654 exit1(td, W_EXITCODE(0, sig)); 655 return (0); 656 } 657 658 659 #ifdef COMPAT_43 660 /* 661 * The dirty work is handled by kern_wait(). 662 */ 663 int 664 owait(struct thread *td, struct owait_args *uap __unused) 665 { 666 int error, status; 667 668 error = kern_wait(td, WAIT_ANY, &status, 0, NULL); 669 if (error == 0) 670 td->td_retval[1] = status; 671 return (error); 672 } 673 #endif /* COMPAT_43 */ 674 675 /* 676 * The dirty work is handled by kern_wait(). 677 */ 678 int 679 wait4(struct thread *td, struct wait_args *uap) 680 { 681 struct rusage ru, *rup; 682 int error, status; 683 684 if (uap->rusage != NULL) 685 rup = &ru; 686 else 687 rup = NULL; 688 error = kern_wait(td, uap->pid, &status, uap->options, rup); 689 if (uap->status != NULL && error == 0) 690 error = copyout(&status, uap->status, sizeof(status)); 691 if (uap->rusage != NULL && error == 0) 692 error = copyout(&ru, uap->rusage, sizeof(struct rusage)); 693 return (error); 694 } 695 696 int 697 kern_wait(struct thread *td, pid_t pid, int *status, int options, 698 struct rusage *rusage) 699 { 700 struct proc *p, *q, *t; 701 int error, nfound; 702 703 AUDIT_ARG(pid, pid); 704 705 q = td->td_proc; 706 if (pid == 0) { 707 PROC_LOCK(q); 708 pid = -q->p_pgid; 709 PROC_UNLOCK(q); 710 } 711 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WNOWAIT|WLINUXCLONE)) 712 return (EINVAL); 713 loop: 714 if (q->p_flag & P_STATCHILD) { 715 PROC_LOCK(q); 716 q->p_flag &= ~P_STATCHILD; 717 PROC_UNLOCK(q); 718 } 719 nfound = 0; 720 sx_xlock(&proctree_lock); 721 LIST_FOREACH(p, &q->p_children, p_sibling) { 722 PROC_LOCK(p); 723 if (pid != WAIT_ANY && 724 p->p_pid != pid && p->p_pgid != -pid) { 725 PROC_UNLOCK(p); 726 continue; 727 } 728 if (p_canwait(td, p)) { 729 PROC_UNLOCK(p); 730 continue; 731 } 732 733 /* 734 * This special case handles a kthread spawned by linux_clone 735 * (see linux_misc.c). The linux_wait4 and linux_waitpid 736 * functions need to be able to distinguish between waiting 737 * on a process and waiting on a thread. It is a thread if 738 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 739 * signifies we want to wait for threads and not processes. 740 */ 741 if ((p->p_sigparent != SIGCHLD) ^ 742 ((options & WLINUXCLONE) != 0)) { 743 PROC_UNLOCK(p); 744 continue; 745 } 746 747 nfound++; 748 PROC_SLOCK(p); 749 if (p->p_state == PRS_ZOMBIE) { 750 if (rusage) { 751 *rusage = p->p_ru; 752 calcru(p, &rusage->ru_utime, &rusage->ru_stime); 753 } 754 PROC_SUNLOCK(p); 755 td->td_retval[0] = p->p_pid; 756 if (status) 757 *status = p->p_xstat; /* convert to int */ 758 if (options & WNOWAIT) { 759 760 /* 761 * Only poll, returning the status. 762 * Caller does not wish to release the proc 763 * struct just yet. 764 */ 765 PROC_UNLOCK(p); 766 sx_xunlock(&proctree_lock); 767 return (0); 768 } 769 770 PROC_LOCK(q); 771 sigqueue_take(p->p_ksi); 772 PROC_UNLOCK(q); 773 PROC_UNLOCK(p); 774 775 /* 776 * If we got the child via a ptrace 'attach', 777 * we need to give it back to the old parent. 778 */ 779 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { 780 PROC_LOCK(p); 781 p->p_oppid = 0; 782 proc_reparent(p, t); 783 PROC_UNLOCK(p); 784 tdsignal(t, NULL, SIGCHLD, p->p_ksi); 785 wakeup(t); 786 PROC_UNLOCK(t); 787 sx_xunlock(&proctree_lock); 788 return (0); 789 } 790 791 /* 792 * Remove other references to this process to ensure 793 * we have an exclusive reference. 794 */ 795 sx_xlock(&allproc_lock); 796 LIST_REMOVE(p, p_list); /* off zombproc */ 797 sx_xunlock(&allproc_lock); 798 LIST_REMOVE(p, p_sibling); 799 leavepgrp(p); 800 sx_xunlock(&proctree_lock); 801 802 /* 803 * As a side effect of this lock, we know that 804 * all other writes to this proc are visible now, so 805 * no more locking is needed for p. 806 */ 807 PROC_LOCK(p); 808 p->p_xstat = 0; /* XXX: why? */ 809 PROC_UNLOCK(p); 810 PROC_LOCK(q); 811 ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, 812 &p->p_rux); 813 PROC_UNLOCK(q); 814 815 /* 816 * Decrement the count of procs running with this uid. 817 */ 818 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 819 820 /* 821 * Free credentials, arguments, and sigacts. 822 */ 823 crfree(p->p_ucred); 824 p->p_ucred = NULL; 825 pargs_drop(p->p_args); 826 p->p_args = NULL; 827 sigacts_free(p->p_sigacts); 828 p->p_sigacts = NULL; 829 830 /* 831 * Do any thread-system specific cleanups. 832 */ 833 thread_wait(p); 834 835 /* 836 * Give vm and machine-dependent layer a chance 837 * to free anything that cpu_exit couldn't 838 * release while still running in process context. 839 */ 840 vm_waitproc(p); 841 #ifdef MAC 842 mac_destroy_proc(p); 843 #endif 844 KASSERT(FIRST_THREAD_IN_PROC(p), 845 ("kern_wait: no residual thread!")); 846 uma_zfree(proc_zone, p); 847 sx_xlock(&allproc_lock); 848 nprocs--; 849 sx_xunlock(&allproc_lock); 850 return (0); 851 } 852 if ((p->p_flag & P_STOPPED_SIG) && 853 (p->p_suspcount == p->p_numthreads) && 854 (p->p_flag & P_WAITED) == 0 && 855 (p->p_flag & P_TRACED || options & WUNTRACED)) { 856 PROC_SUNLOCK(p); 857 p->p_flag |= P_WAITED; 858 sx_xunlock(&proctree_lock); 859 td->td_retval[0] = p->p_pid; 860 if (status) 861 *status = W_STOPCODE(p->p_xstat); 862 863 PROC_LOCK(q); 864 sigqueue_take(p->p_ksi); 865 PROC_UNLOCK(q); 866 PROC_UNLOCK(p); 867 868 return (0); 869 } 870 PROC_SUNLOCK(p); 871 if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { 872 sx_xunlock(&proctree_lock); 873 td->td_retval[0] = p->p_pid; 874 p->p_flag &= ~P_CONTINUED; 875 876 PROC_LOCK(q); 877 sigqueue_take(p->p_ksi); 878 PROC_UNLOCK(q); 879 PROC_UNLOCK(p); 880 881 if (status) 882 *status = SIGCONT; 883 return (0); 884 } 885 PROC_UNLOCK(p); 886 } 887 if (nfound == 0) { 888 sx_xunlock(&proctree_lock); 889 return (ECHILD); 890 } 891 if (options & WNOHANG) { 892 sx_xunlock(&proctree_lock); 893 td->td_retval[0] = 0; 894 return (0); 895 } 896 PROC_LOCK(q); 897 sx_xunlock(&proctree_lock); 898 if (q->p_flag & P_STATCHILD) { 899 q->p_flag &= ~P_STATCHILD; 900 error = 0; 901 } else 902 error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); 903 PROC_UNLOCK(q); 904 if (error) 905 return (error); 906 goto loop; 907 } 908 909 /* 910 * Make process 'parent' the new parent of process 'child'. 911 * Must be called with an exclusive hold of proctree lock. 912 */ 913 void 914 proc_reparent(struct proc *child, struct proc *parent) 915 { 916 917 sx_assert(&proctree_lock, SX_XLOCKED); 918 PROC_LOCK_ASSERT(child, MA_OWNED); 919 if (child->p_pptr == parent) 920 return; 921 922 PROC_LOCK(child->p_pptr); 923 sigqueue_take(child->p_ksi); 924 PROC_UNLOCK(child->p_pptr); 925 LIST_REMOVE(child, p_sibling); 926 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 927 child->p_pptr = parent; 928 }
Cache object: 01a7f7abf792c2d58053bfa4d54dc743
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