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: src/sys/kern/kern_exit.c,v 1.92.2.11 2003/01/13 22:51:16 dillon Exp $ 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/proc.h> 51 #include <sys/pioctl.h> 52 #include <sys/tty.h> 53 #include <sys/wait.h> 54 #include <sys/vnode.h> 55 #include <sys/resourcevar.h> 56 #include <sys/signalvar.h> 57 #include <sys/ptrace.h> 58 #include <sys/acct.h> /* for acct_process() function prototype */ 59 #include <sys/filedesc.h> 60 #include <sys/shm.h> 61 #include <sys/sem.h> 62 #include <sys/aio.h> 63 #include <sys/jail.h> 64 65 #include <vm/vm.h> 66 #include <vm/vm_param.h> 67 #include <sys/lock.h> 68 #include <vm/pmap.h> 69 #include <vm/vm_map.h> 70 #include <vm/vm_zone.h> 71 #include <vm/vm_extern.h> 72 #include <sys/user.h> 73 74 /* Required to be non-static for SysVR4 emulator */ 75 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 76 77 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback"); 78 79 static int wait1 __P((struct proc *, struct wait_args *, int)); 80 81 /* 82 * callout list for things to do at exit time 83 */ 84 struct exitlist { 85 exitlist_fn function; 86 TAILQ_ENTRY(exitlist) next; 87 }; 88 89 TAILQ_HEAD(exit_list_head, exitlist); 90 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list); 91 92 /* 93 * exit -- 94 * Death of process. 95 */ 96 void 97 sys_exit(p, uap) 98 struct proc *p; 99 struct sys_exit_args /* { 100 int rval; 101 } */ *uap; 102 { 103 104 exit1(p, W_EXITCODE(uap->rval, 0)); 105 /* NOTREACHED */ 106 } 107 108 /* 109 * Exit: deallocate address space and other resources, change proc state 110 * to zombie, and unlink proc from allproc and parent's lists. Save exit 111 * status and rusage for wait(). Check for child processes and orphan them. 112 */ 113 void 114 exit1(p, rv) 115 register struct proc *p; 116 int rv; 117 { 118 register struct proc *q, *nq; 119 register struct vmspace *vm; 120 struct vnode *vtmp; 121 struct exitlist *ep; 122 123 if (p->p_pid == 1) { 124 printf("init died (signal %d, exit %d)\n", 125 WTERMSIG(rv), WEXITSTATUS(rv)); 126 panic("Going nowhere without my init!"); 127 } 128 129 aio_proc_rundown(p); 130 131 /* are we a task leader? */ 132 if(p == p->p_leader) { 133 struct kill_args killArgs; 134 killArgs.signum = SIGKILL; 135 q = p->p_peers; 136 while(q) { 137 killArgs.pid = q->p_pid; 138 /* 139 * The interface for kill is better 140 * than the internal signal 141 */ 142 kill(p, &killArgs); 143 nq = q; 144 q = q->p_peers; 145 } 146 while (p->p_peers) 147 tsleep((caddr_t)p, PWAIT, "exit1", 0); 148 } 149 150 #ifdef PGINPROF 151 vmsizmon(); 152 #endif 153 STOPEVENT(p, S_EXIT, rv); 154 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ 155 156 /* 157 * Check if any loadable modules need anything done at process exit. 158 * e.g. SYSV IPC stuff 159 * XXX what if one of these generates an error? 160 */ 161 TAILQ_FOREACH(ep, &exit_list, next) 162 (*ep->function)(p); 163 164 if (p->p_flag & P_PROFIL) 165 stopprofclock(p); 166 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 167 M_ZOMBIE, M_WAITOK); 168 /* 169 * If parent is waiting for us to exit or exec, 170 * P_PPWAIT is set; we will wakeup the parent below. 171 */ 172 p->p_flag &= ~(P_TRACED | P_PPWAIT); 173 p->p_flag |= P_WEXIT; 174 SIGEMPTYSET(p->p_siglist); 175 if (timevalisset(&p->p_realtimer.it_value)) 176 untimeout(realitexpire, (caddr_t)p, p->p_ithandle); 177 178 /* 179 * Reset any sigio structures pointing to us as a result of 180 * F_SETOWN with our pid. 181 */ 182 funsetownlst(&p->p_sigiolst); 183 184 /* 185 * Close open files and release open-file table. 186 * This may block! 187 */ 188 fdfree(p); 189 190 if(p->p_leader->p_peers) { 191 q = p->p_leader; 192 while(q->p_peers != p) 193 q = q->p_peers; 194 q->p_peers = p->p_peers; 195 wakeup((caddr_t)p->p_leader); 196 } 197 198 /* 199 * XXX Shutdown SYSV semaphores 200 */ 201 semexit(p); 202 203 /* The next two chunks should probably be moved to vmspace_exit. */ 204 vm = p->p_vmspace; 205 /* 206 * Release user portion of address space. 207 * This releases references to vnodes, 208 * which could cause I/O if the file has been unlinked. 209 * Need to do this early enough that we can still sleep. 210 * Can't free the entire vmspace as the kernel stack 211 * may be mapped within that space also. 212 * 213 * Processes sharing the same vmspace may exit in one order, and 214 * get cleaned up by vmspace_exit() in a different order. The 215 * last exiting process to reach this point releases as much of 216 * the environment as it can, and the last process cleaned up 217 * by vmspace_exit() (which decrements exitingcnt) cleans up the 218 * remainder. 219 */ 220 ++vm->vm_exitingcnt; 221 if (--vm->vm_refcnt == 0) { 222 if (vm->vm_shm) 223 shmexit(p); 224 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS, 225 VM_MAXUSER_ADDRESS); 226 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS, 227 VM_MAXUSER_ADDRESS); 228 } 229 230 if (SESS_LEADER(p)) { 231 register struct session *sp = p->p_session; 232 233 if (sp->s_ttyvp) { 234 /* 235 * Controlling process. 236 * Signal foreground pgrp, 237 * drain controlling terminal 238 * and revoke access to controlling terminal. 239 */ 240 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 241 if (sp->s_ttyp->t_pgrp) 242 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 243 (void) ttywait(sp->s_ttyp); 244 /* 245 * The tty could have been revoked 246 * if we blocked. 247 */ 248 if (sp->s_ttyvp) 249 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 250 } 251 if (sp->s_ttyvp) 252 vrele(sp->s_ttyvp); 253 sp->s_ttyvp = NULL; 254 /* 255 * s_ttyp is not zero'd; we use this to indicate 256 * that the session once had a controlling terminal. 257 * (for logging and informational purposes) 258 */ 259 } 260 sp->s_leader = NULL; 261 } 262 fixjobc(p, p->p_pgrp, 0); 263 (void)acct_process(p); 264 #ifdef KTRACE 265 /* 266 * release trace file 267 */ 268 p->p_traceflag = 0; /* don't trace the vrele() */ 269 if ((vtmp = p->p_tracep) != NULL) { 270 p->p_tracep = NULL; 271 vrele(vtmp); 272 } 273 #endif 274 /* 275 * Release reference to text vnode 276 */ 277 if ((vtmp = p->p_textvp) != NULL) { 278 p->p_textvp = NULL; 279 vrele(vtmp); 280 } 281 282 /* 283 * Remove proc from allproc queue and pidhash chain. 284 * Place onto zombproc. Unlink from parent's child list. 285 */ 286 LIST_REMOVE(p, p_list); 287 LIST_INSERT_HEAD(&zombproc, p, p_list); 288 p->p_stat = SZOMB; 289 290 LIST_REMOVE(p, p_hash); 291 292 q = LIST_FIRST(&p->p_children); 293 if (q) /* only need this if any child is S_ZOMB */ 294 wakeup((caddr_t) initproc); 295 for (; q != 0; q = nq) { 296 nq = LIST_NEXT(q, p_sibling); 297 LIST_REMOVE(q, p_sibling); 298 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling); 299 q->p_pptr = initproc; 300 q->p_sigparent = SIGCHLD; 301 /* 302 * Traced processes are killed 303 * since their existence means someone is screwing up. 304 */ 305 if (q->p_flag & P_TRACED) { 306 q->p_flag &= ~P_TRACED; 307 psignal(q, SIGKILL); 308 } 309 } 310 311 /* 312 * Save exit status and final rusage info, adding in child rusage 313 * info and self times. 314 */ 315 p->p_xstat = rv; 316 *p->p_ru = p->p_stats->p_ru; 317 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 318 ruadd(p->p_ru, &p->p_stats->p_cru); 319 320 /* 321 * Pretend that an mi_switch() to the next process occurs now. We 322 * must set `switchtime' directly since we will call cpu_switch() 323 * directly. Set it now so that the rest of the exit time gets 324 * counted somewhere if possible. 325 */ 326 microuptime(&switchtime); 327 switchticks = ticks; 328 329 /* 330 * notify interested parties of our demise. 331 */ 332 KNOTE(&p->p_klist, NOTE_EXIT); 333 334 /* 335 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 336 * flag set, notify process 1 instead (and hope it will handle 337 * this situation). 338 */ 339 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) { 340 struct proc *pp = p->p_pptr; 341 proc_reparent(p, initproc); 342 /* 343 * If this was the last child of our parent, notify 344 * parent, so in case he was wait(2)ing, he will 345 * continue. 346 */ 347 if (LIST_EMPTY(&pp->p_children)) 348 wakeup((caddr_t)pp); 349 } 350 351 if (p->p_sigparent && p->p_pptr != initproc) { 352 psignal(p->p_pptr, p->p_sigparent); 353 } else { 354 psignal(p->p_pptr, SIGCHLD); 355 } 356 357 wakeup((caddr_t)p->p_pptr); 358 #if defined(tahoe) 359 /* move this to cpu_exit */ 360 p->p_addr->u_pcb.pcb_savacc.faddr = (float *)NULL; 361 #endif 362 /* 363 * Clear curproc after we've done all operations 364 * that could block, and before tearing down the rest 365 * of the process state that might be used from clock, etc. 366 * Also, can't clear curproc while we're still runnable, 367 * as we're not on a run queue (we are current, just not 368 * a proper proc any longer!). 369 * 370 * Other substructures are freed from wait(). 371 */ 372 SET_CURPROC(NULL); 373 if (--p->p_limit->p_refcnt == 0) { 374 FREE(p->p_limit, M_SUBPROC); 375 p->p_limit = NULL; 376 } 377 378 /* 379 * Finally, call machine-dependent code to release the remaining 380 * resources including address space, the kernel stack and pcb. 381 * The address space is released by "vmspace_free(p->p_vmspace)"; 382 * This is machine-dependent, as we may have to change stacks 383 * or ensure that the current one isn't reallocated before we 384 * finish. cpu_exit will end with a call to cpu_switch(), finishing 385 * our execution (pun intended). 386 */ 387 cpu_exit(p); 388 } 389 390 #ifdef COMPAT_43 391 int 392 owait(p, uap) 393 struct proc *p; 394 register struct owait_args /* { 395 int dummy; 396 } */ *uap; 397 { 398 struct wait_args w; 399 400 w.options = 0; 401 w.rusage = NULL; 402 w.pid = WAIT_ANY; 403 w.status = NULL; 404 return (wait1(p, &w, 1)); 405 } 406 #endif /* COMPAT_43 */ 407 408 int 409 wait4(p, uap) 410 struct proc *p; 411 struct wait_args *uap; 412 { 413 414 return (wait1(p, uap, 0)); 415 } 416 417 static int 418 wait1(q, uap, compat) 419 register struct proc *q; 420 register struct wait_args /* { 421 int pid; 422 int *status; 423 int options; 424 struct rusage *rusage; 425 } */ *uap; 426 int compat; 427 { 428 register int nfound; 429 register struct proc *p, *t; 430 int status, error; 431 432 if (uap->pid == 0) 433 uap->pid = -q->p_pgid; 434 if (uap->options &~ (WUNTRACED|WNOHANG|WLINUXCLONE)) 435 return (EINVAL); 436 loop: 437 nfound = 0; 438 LIST_FOREACH(p, &q->p_children, p_sibling) { 439 if (uap->pid != WAIT_ANY && 440 p->p_pid != uap->pid && p->p_pgid != -uap->pid) 441 continue; 442 443 /* This special case handles a kthread spawned by linux_clone 444 * (see linux_misc.c). The linux_wait4 and linux_waitpid functions 445 * need to be able to distinguish between waiting on a process and 446 * waiting on a thread. It is a thread if p_sigparent is not SIGCHLD, 447 * and the WLINUXCLONE option signifies we want to wait for threads 448 * and not processes. 449 */ 450 if ((p->p_sigparent != SIGCHLD) ^ ((uap->options & WLINUXCLONE) != 0)) 451 continue; 452 453 nfound++; 454 if (p->p_stat == SZOMB) { 455 /* charge childs scheduling cpu usage to parent */ 456 if (curproc->p_pid != 1) { 457 curproc->p_estcpu = 458 ESTCPULIM(curproc->p_estcpu + p->p_estcpu); 459 } 460 461 q->p_retval[0] = p->p_pid; 462 #ifdef COMPAT_43 463 if (compat) 464 q->p_retval[1] = p->p_xstat; 465 else 466 #endif 467 if (uap->status) { 468 status = p->p_xstat; /* convert to int */ 469 if ((error = copyout((caddr_t)&status, 470 (caddr_t)uap->status, sizeof(status)))) 471 return (error); 472 } 473 if (uap->rusage && (error = copyout((caddr_t)p->p_ru, 474 (caddr_t)uap->rusage, sizeof (struct rusage)))) 475 return (error); 476 /* 477 * If we got the child via a ptrace 'attach', 478 * we need to give it back to the old parent. 479 */ 480 if (p->p_oppid && (t = pfind(p->p_oppid))) { 481 p->p_oppid = 0; 482 proc_reparent(p, t); 483 psignal(t, SIGCHLD); 484 wakeup((caddr_t)t); 485 return (0); 486 } 487 p->p_xstat = 0; 488 ruadd(&q->p_stats->p_cru, p->p_ru); 489 FREE(p->p_ru, M_ZOMBIE); 490 p->p_ru = NULL; 491 492 /* 493 * Decrement the count of procs running with this uid. 494 */ 495 (void)chgproccnt(p->p_cred->p_uidinfo, -1, 0); 496 497 /* 498 * Free up credentials. 499 */ 500 if (--p->p_cred->p_refcnt == 0) { 501 crfree(p->p_ucred); 502 uifree(p->p_cred->p_uidinfo); 503 FREE(p->p_cred, M_SUBPROC); 504 p->p_cred = NULL; 505 } 506 507 /* 508 * Destroy empty prisons 509 */ 510 if (p->p_prison && !--p->p_prison->pr_ref) { 511 if (p->p_prison->pr_linux != NULL) 512 FREE(p->p_prison->pr_linux, M_PRISON); 513 FREE(p->p_prison, M_PRISON); 514 } 515 516 /* 517 * Remove unused arguments 518 */ 519 if (p->p_args && --p->p_args->ar_ref == 0) 520 FREE(p->p_args, M_PARGS); 521 522 /* 523 * Finally finished with old proc entry. 524 * Unlink it from its process group and free it. 525 */ 526 leavepgrp(p); 527 LIST_REMOVE(p, p_list); /* off zombproc */ 528 LIST_REMOVE(p, p_sibling); 529 530 if (--p->p_procsig->ps_refcnt == 0) { 531 if (p->p_sigacts != &p->p_addr->u_sigacts) 532 FREE(p->p_sigacts, M_SUBPROC); 533 FREE(p->p_procsig, M_SUBPROC); 534 p->p_procsig = NULL; 535 } 536 537 /* 538 * Give machine-dependent layer a chance 539 * to free anything that cpu_exit couldn't 540 * release while still running in process context. 541 */ 542 vm_waitproc(p); 543 zfree(proc_zone, p); 544 nprocs--; 545 return (0); 546 } 547 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 548 (p->p_flag & P_TRACED || uap->options & WUNTRACED)) { 549 p->p_flag |= P_WAITED; 550 q->p_retval[0] = p->p_pid; 551 #ifdef COMPAT_43 552 if (compat) { 553 q->p_retval[1] = W_STOPCODE(p->p_xstat); 554 error = 0; 555 } else 556 #endif 557 if (uap->status) { 558 status = W_STOPCODE(p->p_xstat); 559 error = copyout((caddr_t)&status, 560 (caddr_t)uap->status, sizeof(status)); 561 } else 562 error = 0; 563 return (error); 564 } 565 } 566 if (nfound == 0) 567 return (ECHILD); 568 if (uap->options & WNOHANG) { 569 q->p_retval[0] = 0; 570 return (0); 571 } 572 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0))) 573 return (error); 574 goto loop; 575 } 576 577 /* 578 * make process 'parent' the new parent of process 'child'. 579 */ 580 void 581 proc_reparent(child, parent) 582 register struct proc *child; 583 register struct proc *parent; 584 { 585 586 if (child->p_pptr == parent) 587 return; 588 589 LIST_REMOVE(child, p_sibling); 590 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 591 child->p_pptr = parent; 592 } 593 594 /* 595 * The next two functions are to handle adding/deleting items on the 596 * exit callout list 597 * 598 * at_exit(): 599 * Take the arguments given and put them onto the exit callout list, 600 * However first make sure that it's not already there. 601 * returns 0 on success. 602 */ 603 604 int 605 at_exit(function) 606 exitlist_fn function; 607 { 608 struct exitlist *ep; 609 610 #ifdef INVARIANTS 611 /* Be noisy if the programmer has lost track of things */ 612 if (rm_at_exit(function)) 613 printf("WARNING: exit callout entry (%p) already present\n", 614 function); 615 #endif 616 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT); 617 if (ep == NULL) 618 return (ENOMEM); 619 ep->function = function; 620 TAILQ_INSERT_TAIL(&exit_list, ep, next); 621 return (0); 622 } 623 624 /* 625 * Scan the exit callout list for the given item and remove it. 626 * Returns the number of items removed (0 or 1) 627 */ 628 int 629 rm_at_exit(function) 630 exitlist_fn function; 631 { 632 struct exitlist *ep; 633 634 TAILQ_FOREACH(ep, &exit_list, next) { 635 if (ep->function == function) { 636 TAILQ_REMOVE(&exit_list, ep, next); 637 free(ep, M_ATEXIT); 638 return(1); 639 } 640 } 641 return (0); 642 } 643 644 void check_sigacts (void) 645 { 646 struct proc *p = curproc; 647 struct sigacts *pss; 648 int s; 649 650 if (p->p_procsig->ps_refcnt == 1 && 651 p->p_sigacts != &p->p_addr->u_sigacts) { 652 pss = p->p_sigacts; 653 s = splhigh(); 654 p->p_addr->u_sigacts = *pss; 655 p->p_sigacts = &p->p_addr->u_sigacts; 656 splx(s); 657 FREE(pss, M_SUBPROC); 658 } 659 } 660 661