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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 39 * $FreeBSD$ 40 */ 41 42 #include "opt_compat.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/kernel.h> 49 #include <sys/malloc.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/proc.h> 53 #include <sys/pioctl.h> 54 #include <sys/tty.h> 55 #include <sys/wait.h> 56 #include <sys/vnode.h> 57 #include <sys/vmmeter.h> 58 #include <sys/resourcevar.h> 59 #include <sys/signalvar.h> 60 #include <sys/sx.h> 61 #include <sys/ptrace.h> 62 #include <sys/acct.h> /* for acct_process() function prototype */ 63 #include <sys/filedesc.h> 64 #include <sys/shm.h> 65 #include <sys/sem.h> 66 #include <sys/jail.h> 67 68 #include <vm/vm.h> 69 #include <vm/vm_param.h> 70 #include <vm/vm_extern.h> 71 #include <vm/pmap.h> 72 #include <vm/vm_map.h> 73 #include <vm/vm_zone.h> 74 #include <sys/user.h> 75 76 /* Required to be non-static for SysVR4 emulator */ 77 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 78 79 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback"); 80 81 static int wait1 __P((struct thread *, struct wait_args *, int)); 82 83 /* 84 * callout list for things to do at exit time 85 */ 86 struct exitlist { 87 exitlist_fn function; 88 TAILQ_ENTRY(exitlist) next; 89 }; 90 91 TAILQ_HEAD(exit_list_head, exitlist); 92 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list); 93 94 /* 95 * exit -- 96 * Death of process. 97 * 98 * MPSAFE 99 */ 100 void 101 sys_exit(td, uap) 102 struct thread *td; 103 struct sys_exit_args /* { 104 int rval; 105 } */ *uap; 106 { 107 108 mtx_lock(&Giant); 109 exit1(td, W_EXITCODE(uap->rval, 0)); 110 /* NOTREACHED */ 111 } 112 113 /* 114 * Exit: deallocate address space and other resources, change proc state 115 * to zombie, and unlink proc from allproc and parent's lists. Save exit 116 * status and rusage for wait(). Check for child processes and orphan them. 117 */ 118 void 119 exit1(td, rv) 120 register struct thread *td; 121 int rv; 122 { 123 struct proc *p = td->td_proc; 124 register struct proc *q, *nq; 125 register struct vmspace *vm; 126 #ifdef KTRACE 127 struct vnode *vtmp; 128 #endif 129 struct exitlist *ep; 130 131 GIANT_REQUIRED; 132 133 if (p->p_pid == 1) { 134 printf("init died (signal %d, exit %d)\n", 135 WTERMSIG(rv), WEXITSTATUS(rv)); 136 panic("Going nowhere without my init!"); 137 } 138 139 /* XXXXKSE */ 140 /* MUST abort all other threads before proceeding past this point */ 141 142 /* are we a task leader? */ 143 PROC_LOCK(p); 144 if(p == p->p_leader) { 145 q = p->p_peers; 146 while (q != NULL) { 147 PROC_LOCK(q); 148 psignal(q, SIGKILL); 149 PROC_UNLOCK(q); 150 q = q->p_peers; 151 } 152 while (p->p_peers) 153 msleep((caddr_t)p, &p->p_mtx, PWAIT, "exit1", 0); 154 } 155 PROC_UNLOCK(p); 156 157 #ifdef PGINPROF 158 vmsizmon(); 159 #endif 160 STOPEVENT(p, S_EXIT, rv); 161 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ 162 163 /* 164 * Check if any loadable modules need anything done at process exit. 165 * e.g. SYSV IPC stuff 166 * XXX what if one of these generates an error? 167 */ 168 TAILQ_FOREACH(ep, &exit_list, next) 169 (*ep->function)(p); 170 171 stopprofclock(p); 172 173 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 174 M_ZOMBIE, M_WAITOK); 175 /* 176 * If parent is waiting for us to exit or exec, 177 * P_PPWAIT is set; we will wakeup the parent below. 178 */ 179 PROC_LOCK(p); 180 p->p_flag &= ~(P_TRACED | P_PPWAIT); 181 p->p_flag |= P_WEXIT; 182 SIGEMPTYSET(p->p_siglist); 183 PROC_UNLOCK(p); 184 if (timevalisset(&p->p_realtimer.it_value)) 185 callout_stop(&p->p_itcallout); 186 187 /* 188 * Reset any sigio structures pointing to us as a result of 189 * F_SETOWN with our pid. 190 */ 191 funsetownlst(&p->p_sigiolst); 192 193 /* 194 * Close open files and release open-file table. 195 * This may block! 196 */ 197 fdfree(td); /* XXXKSE *//* may not be the one in proc */ 198 199 /* 200 * Remove ourself from our leader's peer list and wake our leader. 201 */ 202 PROC_LOCK(p->p_leader); 203 if(p->p_leader->p_peers) { 204 q = p->p_leader; 205 while(q->p_peers != p) 206 q = q->p_peers; 207 q->p_peers = p->p_peers; 208 wakeup((caddr_t)p->p_leader); 209 } 210 PROC_UNLOCK(p->p_leader); 211 212 /* The next two chunks should probably be moved to vmspace_exit. */ 213 vm = p->p_vmspace; 214 /* 215 * Release user portion of address space. 216 * This releases references to vnodes, 217 * which could cause I/O if the file has been unlinked. 218 * Need to do this early enough that we can still sleep. 219 * Can't free the entire vmspace as the kernel stack 220 * may be mapped within that space also. 221 */ 222 if (vm->vm_refcnt == 1) { 223 if (vm->vm_shm) 224 shmexit(p); 225 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS, 226 VM_MAXUSER_ADDRESS); 227 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS, 228 VM_MAXUSER_ADDRESS); 229 } 230 231 PROC_LOCK(p); 232 if (SESS_LEADER(p)) { 233 register struct session *sp = p->p_session; 234 235 PROC_UNLOCK(p); 236 if (sp->s_ttyvp) { 237 /* 238 * Controlling process. 239 * Signal foreground pgrp, 240 * drain controlling terminal 241 * and revoke access to controlling terminal. 242 */ 243 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 244 if (sp->s_ttyp->t_pgrp) 245 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 246 (void) ttywait(sp->s_ttyp); 247 /* 248 * The tty could have been revoked 249 * if we blocked. 250 */ 251 if (sp->s_ttyvp) 252 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 253 } 254 if (sp->s_ttyvp) 255 vrele(sp->s_ttyvp); 256 sp->s_ttyvp = NULL; 257 /* 258 * s_ttyp is not zero'd; we use this to indicate 259 * that the session once had a controlling terminal. 260 * (for logging and informational purposes) 261 */ 262 } 263 sp->s_leader = NULL; 264 } else 265 PROC_UNLOCK(p); 266 fixjobc(p, p->p_pgrp, 0); 267 (void)acct_process(td); 268 #ifdef KTRACE 269 /* 270 * release trace file 271 */ 272 p->p_traceflag = 0; /* don't trace the vrele() */ 273 if ((vtmp = p->p_tracep) != NULL) { 274 p->p_tracep = NULL; 275 vrele(vtmp); 276 } 277 #endif 278 /* 279 * Remove proc from allproc queue and pidhash chain. 280 * Place onto zombproc. Unlink from parent's child list. 281 */ 282 sx_xlock(&allproc_lock); 283 LIST_REMOVE(p, p_list); 284 LIST_INSERT_HEAD(&zombproc, p, p_list); 285 LIST_REMOVE(p, p_hash); 286 sx_xunlock(&allproc_lock); 287 288 sx_xlock(&proctree_lock); 289 q = LIST_FIRST(&p->p_children); 290 if (q != NULL) /* only need this if any child is S_ZOMB */ 291 wakeup((caddr_t) initproc); 292 for (; q != NULL; q = nq) { 293 nq = LIST_NEXT(q, p_sibling); 294 PROC_LOCK(q); 295 proc_reparent(q, initproc); 296 q->p_sigparent = SIGCHLD; 297 /* 298 * Traced processes are killed 299 * since their existence means someone is screwing up. 300 */ 301 if (q->p_flag & P_TRACED) { 302 q->p_flag &= ~P_TRACED; 303 psignal(q, SIGKILL); 304 } 305 PROC_UNLOCK(q); 306 } 307 308 /* 309 * Save exit status and final rusage info, adding in child rusage 310 * info and self times. 311 */ 312 p->p_xstat = rv; 313 *p->p_ru = p->p_stats->p_ru; 314 mtx_lock_spin(&sched_lock); 315 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 316 mtx_unlock_spin(&sched_lock); 317 ruadd(p->p_ru, &p->p_stats->p_cru); 318 319 /* 320 * Pretend that an mi_switch() to the next process occurs now. We 321 * must set `switchtime' directly since we will call cpu_switch() 322 * directly. Set it now so that the rest of the exit time gets 323 * counted somewhere if possible. 324 */ 325 mtx_lock_spin(&sched_lock); 326 microuptime(PCPU_PTR(switchtime)); 327 PCPU_SET(switchticks, ticks); 328 mtx_unlock_spin(&sched_lock); 329 330 /* 331 * notify interested parties of our demise. 332 */ 333 PROC_LOCK(p); 334 KNOTE(&p->p_klist, NOTE_EXIT); 335 336 /* 337 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 338 * flag set, notify process 1 instead (and hope it will handle 339 * this situation). 340 */ 341 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) { 342 struct proc *pp = p->p_pptr; 343 proc_reparent(p, initproc); 344 /* 345 * If this was the last child of our parent, notify 346 * parent, so in case he was wait(2)ing, he will 347 * continue. 348 */ 349 if (LIST_EMPTY(&pp->p_children)) 350 wakeup((caddr_t)pp); 351 } 352 353 PROC_LOCK(p->p_pptr); 354 if (p->p_sigparent && p->p_pptr != initproc) 355 psignal(p->p_pptr, p->p_sigparent); 356 else 357 psignal(p->p_pptr, SIGCHLD); 358 PROC_UNLOCK(p->p_pptr); 359 360 /* 361 * If this is a kthread, then wakeup anyone waiting for it to exit. 362 */ 363 if (p->p_flag & P_KTHREAD) 364 wakeup((caddr_t)p); 365 PROC_UNLOCK(p); 366 sx_xunlock(&proctree_lock); 367 368 /* 369 * Clear curproc after we've done all operations 370 * that could block, and before tearing down the rest 371 * of the process state that might be used from clock, etc. 372 * Also, can't clear curproc while we're still runnable, 373 * as we're not on a run queue (we are current, just not 374 * a proper proc any longer!). 375 * 376 * Other substructures are freed from wait(). 377 */ 378 mtx_assert(&Giant, MA_OWNED); 379 if (--p->p_limit->p_refcnt == 0) { 380 FREE(p->p_limit, M_SUBPROC); 381 p->p_limit = NULL; 382 } 383 384 /* 385 * Release this thread's reference to the ucred. The actual proc 386 * reference will stay around until the proc is harvested by 387 * wait(). At this point the ucred is immutable (no other threads 388 * from this proc are around that can change it) so we leave the 389 * per-thread ucred pointer intact in case it is needed although 390 * in theory nothing should be using it at this point. 391 */ 392 crfree(td->td_ucred); 393 394 /* 395 * Finally, call machine-dependent code to release the remaining 396 * resources including address space, the kernel stack and pcb. 397 * The address space is released by "vmspace_free(p->p_vmspace)" 398 * in vm_waitproc(); 399 */ 400 cpu_exit(td); 401 402 PROC_LOCK(p); 403 mtx_lock_spin(&sched_lock); 404 while (mtx_owned(&Giant)) 405 mtx_unlock_flags(&Giant, MTX_NOSWITCH); 406 407 /* 408 * We have to wait until after releasing all locks before 409 * changing p_stat. If we block on a mutex then we will be 410 * back at SRUN when we resume and our parent will never 411 * harvest us. 412 */ 413 p->p_stat = SZOMB; 414 415 wakeup(p->p_pptr); 416 PROC_UNLOCK_NOSWITCH(p); 417 418 cnt.v_swtch++; 419 cpu_throw(); 420 panic("exit1"); 421 } 422 423 #ifdef COMPAT_43 424 /* 425 * MPSAFE, the dirty work is handled by wait1(). 426 */ 427 int 428 owait(td, uap) 429 struct thread *td; 430 register struct owait_args /* { 431 int dummy; 432 } */ *uap; 433 { 434 struct wait_args w; 435 436 w.options = 0; 437 w.rusage = NULL; 438 w.pid = WAIT_ANY; 439 w.status = NULL; 440 return (wait1(td, &w, 1)); 441 } 442 #endif /* COMPAT_43 */ 443 444 /* 445 * MPSAFE, the dirty work is handled by wait1(). 446 */ 447 int 448 wait4(td, uap) 449 struct thread *td; 450 struct wait_args *uap; 451 { 452 453 return (wait1(td, uap, 0)); 454 } 455 456 /* 457 * MPSAFE 458 */ 459 static int 460 wait1(td, uap, compat) 461 register struct thread *td; 462 register struct wait_args /* { 463 int pid; 464 int *status; 465 int options; 466 struct rusage *rusage; 467 } */ *uap; 468 int compat; 469 { 470 register int nfound; 471 register struct proc *q, *p, *t; 472 int status, error; 473 474 mtx_lock(&Giant); 475 q = td->td_proc; 476 if (uap->pid == 0) 477 uap->pid = -q->p_pgid; 478 if (uap->options &~ (WUNTRACED|WNOHANG|WLINUXCLONE)) { 479 error = EINVAL; 480 goto done2; 481 } 482 loop: 483 nfound = 0; 484 sx_slock(&proctree_lock); 485 LIST_FOREACH(p, &q->p_children, p_sibling) { 486 if (uap->pid != WAIT_ANY && 487 p->p_pid != uap->pid && p->p_pgid != -uap->pid) 488 continue; 489 490 /* 491 * This special case handles a kthread spawned by linux_clone 492 * (see linux_misc.c). The linux_wait4 and linux_waitpid 493 * functions need to be able to distinguish between waiting 494 * on a process and waiting on a thread. It is a thread if 495 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 496 * signifies we want to wait for threads and not processes. 497 */ 498 PROC_LOCK(p); 499 if ((p->p_sigparent != SIGCHLD) ^ 500 ((uap->options & WLINUXCLONE) != 0)) { 501 PROC_UNLOCK(p); 502 continue; 503 } 504 505 nfound++; 506 mtx_lock_spin(&sched_lock); 507 if (p->p_stat == SZOMB) { 508 /* 509 * charge childs scheduling cpu usage to parent 510 * XXXKSE assume only one thread & kse & ksegrp 511 * keep estcpu in each ksegrp 512 * so charge it to the ksegrp that did the wait 513 * since process estcpu is sum of all ksegrps, 514 * this is strictly as expected. 515 * Assume that the child process aggregated all 516 * tke estcpu into the 'build-in' ksegrp. 517 * XXXKSE 518 */ 519 if (curthread->td_proc->p_pid != 1) { 520 curthread->td_ksegrp->kg_estcpu = 521 ESTCPULIM(curthread->td_ksegrp->kg_estcpu + 522 p->p_ksegrp.kg_estcpu); 523 } 524 525 mtx_unlock_spin(&sched_lock); 526 PROC_UNLOCK(p); 527 sx_sunlock(&proctree_lock); 528 529 td->td_retval[0] = p->p_pid; 530 #ifdef COMPAT_43 531 if (compat) 532 td->td_retval[1] = p->p_xstat; 533 else 534 #endif 535 if (uap->status) { 536 status = p->p_xstat; /* convert to int */ 537 if ((error = copyout((caddr_t)&status, 538 (caddr_t)uap->status, sizeof(status)))) { 539 goto done2; 540 } 541 } 542 if (uap->rusage && (error = copyout((caddr_t)p->p_ru, 543 (caddr_t)uap->rusage, sizeof (struct rusage)))) { 544 goto done2; 545 } 546 /* 547 * If we got the child via a ptrace 'attach', 548 * we need to give it back to the old parent. 549 */ 550 sx_xlock(&proctree_lock); 551 if (p->p_oppid) { 552 if ((t = pfind(p->p_oppid)) != NULL) { 553 PROC_LOCK(p); 554 p->p_oppid = 0; 555 proc_reparent(p, t); 556 PROC_UNLOCK(p); 557 psignal(t, SIGCHLD); 558 wakeup((caddr_t)t); 559 PROC_UNLOCK(t); 560 sx_xunlock(&proctree_lock); 561 error = 0; 562 goto done2; 563 } 564 } 565 sx_xunlock(&proctree_lock); 566 PROC_LOCK(p); 567 p->p_xstat = 0; 568 PROC_UNLOCK(p); 569 ruadd(&q->p_stats->p_cru, p->p_ru); 570 FREE(p->p_ru, M_ZOMBIE); 571 p->p_ru = NULL; 572 573 /* 574 * Decrement the count of procs running with this uid. 575 */ 576 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 577 578 /* 579 * Release reference to text vnode 580 */ 581 if (p->p_textvp) 582 vrele(p->p_textvp); 583 584 /* 585 * Finally finished with old proc entry. 586 * Unlink it from its process group and free it. 587 */ 588 leavepgrp(p); 589 590 sx_xlock(&allproc_lock); 591 LIST_REMOVE(p, p_list); /* off zombproc */ 592 sx_xunlock(&allproc_lock); 593 594 sx_xlock(&proctree_lock); 595 LIST_REMOVE(p, p_sibling); 596 sx_xunlock(&proctree_lock); 597 598 /* 599 * Free up credentials. 600 */ 601 crfree(p->p_ucred); 602 p->p_ucred = NULL; 603 604 /* 605 * Remove unused arguments 606 */ 607 if (p->p_args && --p->p_args->ar_ref == 0) 608 FREE(p->p_args, M_PARGS); 609 610 if (--p->p_procsig->ps_refcnt == 0) { 611 if (p->p_sigacts != &p->p_uarea->u_sigacts) 612 FREE(p->p_sigacts, M_SUBPROC); 613 FREE(p->p_procsig, M_SUBPROC); 614 p->p_procsig = NULL; 615 } 616 617 /* 618 * Give vm and machine-dependent layer a chance 619 * to free anything that cpu_exit couldn't 620 * release while still running in process context. 621 */ 622 vm_waitproc(p); 623 mtx_destroy(&p->p_mtx); 624 zfree(proc_zone, p); 625 nprocs--; 626 error = 0; 627 goto done2; 628 } 629 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 630 (p->p_flag & P_TRACED || uap->options & WUNTRACED)) { 631 mtx_unlock_spin(&sched_lock); 632 p->p_flag |= P_WAITED; 633 PROC_UNLOCK(p); 634 sx_sunlock(&proctree_lock); 635 td->td_retval[0] = p->p_pid; 636 #ifdef COMPAT_43 637 if (compat) { 638 td->td_retval[1] = W_STOPCODE(p->p_xstat); 639 error = 0; 640 } else 641 #endif 642 if (uap->status) { 643 status = W_STOPCODE(p->p_xstat); 644 error = copyout((caddr_t)&status, 645 (caddr_t)uap->status, sizeof(status)); 646 } else 647 error = 0; 648 goto done2; 649 } 650 mtx_unlock_spin(&sched_lock); 651 PROC_UNLOCK(p); 652 } 653 sx_sunlock(&proctree_lock); 654 if (nfound == 0) { 655 error = ECHILD; 656 goto done2; 657 } 658 if (uap->options & WNOHANG) { 659 td->td_retval[0] = 0; 660 error = 0; 661 goto done2; 662 } 663 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 664 goto done2; 665 goto loop; 666 done2: 667 mtx_unlock(&Giant); 668 return(error); 669 } 670 671 /* 672 * Make process 'parent' the new parent of process 'child'. 673 * Must be called with an exclusive hold of proctree lock. 674 */ 675 void 676 proc_reparent(child, parent) 677 register struct proc *child; 678 register struct proc *parent; 679 { 680 681 sx_assert(&proctree_lock, SX_XLOCKED); 682 PROC_LOCK_ASSERT(child, MA_OWNED); 683 if (child->p_pptr == parent) 684 return; 685 686 LIST_REMOVE(child, p_sibling); 687 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 688 child->p_pptr = parent; 689 } 690 691 /* 692 * The next two functions are to handle adding/deleting items on the 693 * exit callout list 694 * 695 * at_exit(): 696 * Take the arguments given and put them onto the exit callout list, 697 * However first make sure that it's not already there. 698 * returns 0 on success. 699 */ 700 701 int 702 at_exit(function) 703 exitlist_fn function; 704 { 705 struct exitlist *ep; 706 707 #ifdef INVARIANTS 708 /* Be noisy if the programmer has lost track of things */ 709 if (rm_at_exit(function)) 710 printf("WARNING: exit callout entry (%p) already present\n", 711 function); 712 #endif 713 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT); 714 if (ep == NULL) 715 return (ENOMEM); 716 ep->function = function; 717 TAILQ_INSERT_TAIL(&exit_list, ep, next); 718 return (0); 719 } 720 721 /* 722 * Scan the exit callout list for the given item and remove it. 723 * Returns the number of items removed (0 or 1) 724 */ 725 int 726 rm_at_exit(function) 727 exitlist_fn function; 728 { 729 struct exitlist *ep; 730 731 TAILQ_FOREACH(ep, &exit_list, next) { 732 if (ep->function == function) { 733 TAILQ_REMOVE(&exit_list, ep, next); 734 free(ep, M_ATEXIT); 735 return(1); 736 } 737 } 738 return (0); 739 } 740