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