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 * $DragonFly: src/sys/kern/kern_exit.c,v 1.2 2003/06/17 04:28:41 dillon Exp $ 41 */ 42 43 #include "opt_compat.h" 44 #include "opt_ktrace.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/sysproto.h> 49 #include <sys/kernel.h> 50 #include <sys/malloc.h> 51 #include <sys/proc.h> 52 #include <sys/pioctl.h> 53 #include <sys/tty.h> 54 #include <sys/wait.h> 55 #include <sys/vnode.h> 56 #include <sys/resourcevar.h> 57 #include <sys/signalvar.h> 58 #include <sys/ptrace.h> 59 #include <sys/acct.h> /* for acct_process() function prototype */ 60 #include <sys/filedesc.h> 61 #include <sys/shm.h> 62 #include <sys/sem.h> 63 #include <sys/aio.h> 64 #include <sys/jail.h> 65 66 #include <vm/vm.h> 67 #include <vm/vm_param.h> 68 #include <sys/lock.h> 69 #include <vm/pmap.h> 70 #include <vm/vm_map.h> 71 #include <vm/vm_zone.h> 72 #include <vm/vm_extern.h> 73 #include <sys/user.h> 74 75 /* Required to be non-static for SysVR4 emulator */ 76 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 77 78 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback"); 79 80 static int wait1 __P((struct proc *, struct wait_args *, int)); 81 82 /* 83 * callout list for things to do at exit time 84 */ 85 struct exitlist { 86 exitlist_fn function; 87 TAILQ_ENTRY(exitlist) next; 88 }; 89 90 TAILQ_HEAD(exit_list_head, exitlist); 91 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list); 92 93 /* 94 * exit -- 95 * Death of process. 96 */ 97 void 98 sys_exit(p, uap) 99 struct proc *p; 100 struct sys_exit_args /* { 101 int rval; 102 } */ *uap; 103 { 104 105 exit1(p, W_EXITCODE(uap->rval, 0)); 106 /* NOTREACHED */ 107 } 108 109 /* 110 * Exit: deallocate address space and other resources, change proc state 111 * to zombie, and unlink proc from allproc and parent's lists. Save exit 112 * status and rusage for wait(). Check for child processes and orphan them. 113 */ 114 void 115 exit1(p, rv) 116 register struct proc *p; 117 int rv; 118 { 119 register struct proc *q, *nq; 120 register struct vmspace *vm; 121 struct vnode *vtmp; 122 struct exitlist *ep; 123 124 if (p->p_pid == 1) { 125 printf("init died (signal %d, exit %d)\n", 126 WTERMSIG(rv), WEXITSTATUS(rv)); 127 panic("Going nowhere without my init!"); 128 } 129 130 aio_proc_rundown(p); 131 132 /* are we a task leader? */ 133 if(p == p->p_leader) { 134 struct kill_args killArgs; 135 killArgs.signum = SIGKILL; 136 q = p->p_peers; 137 while(q) { 138 killArgs.pid = q->p_pid; 139 /* 140 * The interface for kill is better 141 * than the internal signal 142 */ 143 kill(p, &killArgs); 144 nq = q; 145 q = q->p_peers; 146 } 147 while (p->p_peers) 148 tsleep((caddr_t)p, PWAIT, "exit1", 0); 149 } 150 151 #ifdef PGINPROF 152 vmsizmon(); 153 #endif 154 STOPEVENT(p, S_EXIT, rv); 155 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ 156 157 /* 158 * Check if any loadable modules need anything done at process exit. 159 * e.g. SYSV IPC stuff 160 * XXX what if one of these generates an error? 161 */ 162 TAILQ_FOREACH(ep, &exit_list, next) 163 (*ep->function)(p); 164 165 if (p->p_flag & P_PROFIL) 166 stopprofclock(p); 167 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 168 M_ZOMBIE, M_WAITOK); 169 /* 170 * If parent is waiting for us to exit or exec, 171 * P_PPWAIT is set; we will wakeup the parent below. 172 */ 173 p->p_flag &= ~(P_TRACED | P_PPWAIT); 174 p->p_flag |= P_WEXIT; 175 SIGEMPTYSET(p->p_siglist); 176 if (timevalisset(&p->p_realtimer.it_value)) 177 untimeout(realitexpire, (caddr_t)p, p->p_ithandle); 178 179 /* 180 * Reset any sigio structures pointing to us as a result of 181 * F_SETOWN with our pid. 182 */ 183 funsetownlst(&p->p_sigiolst); 184 185 /* 186 * Close open files and release open-file table. 187 * This may block! 188 */ 189 fdfree(p); 190 191 if(p->p_leader->p_peers) { 192 q = p->p_leader; 193 while(q->p_peers != p) 194 q = q->p_peers; 195 q->p_peers = p->p_peers; 196 wakeup((caddr_t)p->p_leader); 197 } 198 199 /* 200 * XXX Shutdown SYSV semaphores 201 */ 202 semexit(p); 203 204 /* The next two chunks should probably be moved to vmspace_exit. */ 205 vm = p->p_vmspace; 206 /* 207 * Release user portion of address space. 208 * This releases references to vnodes, 209 * which could cause I/O if the file has been unlinked. 210 * Need to do this early enough that we can still sleep. 211 * Can't free the entire vmspace as the kernel stack 212 * may be mapped within that space also. 213 * 214 * Processes sharing the same vmspace may exit in one order, and 215 * get cleaned up by vmspace_exit() in a different order. The 216 * last exiting process to reach this point releases as much of 217 * the environment as it can, and the last process cleaned up 218 * by vmspace_exit() (which decrements exitingcnt) cleans up the 219 * remainder. 220 */ 221 ++vm->vm_exitingcnt; 222 if (--vm->vm_refcnt == 0) { 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 if (SESS_LEADER(p)) { 232 register struct session *sp = p->p_session; 233 234 if (sp->s_ttyvp) { 235 /* 236 * Controlling process. 237 * Signal foreground pgrp, 238 * drain controlling terminal 239 * and revoke access to controlling terminal. 240 */ 241 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 242 if (sp->s_ttyp->t_pgrp) 243 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 244 (void) ttywait(sp->s_ttyp); 245 /* 246 * The tty could have been revoked 247 * if we blocked. 248 */ 249 if (sp->s_ttyvp) 250 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 251 } 252 if (sp->s_ttyvp) 253 vrele(sp->s_ttyvp); 254 sp->s_ttyvp = NULL; 255 /* 256 * s_ttyp is not zero'd; we use this to indicate 257 * that the session once had a controlling terminal. 258 * (for logging and informational purposes) 259 */ 260 } 261 sp->s_leader = NULL; 262 } 263 fixjobc(p, p->p_pgrp, 0); 264 (void)acct_process(p); 265 #ifdef KTRACE 266 /* 267 * release trace file 268 */ 269 p->p_traceflag = 0; /* don't trace the vrele() */ 270 if ((vtmp = p->p_tracep) != NULL) { 271 p->p_tracep = NULL; 272 vrele(vtmp); 273 } 274 #endif 275 /* 276 * Release reference to text vnode 277 */ 278 if ((vtmp = p->p_textvp) != NULL) { 279 p->p_textvp = NULL; 280 vrele(vtmp); 281 } 282 283 /* 284 * Remove proc from allproc queue and pidhash chain. 285 * Place onto zombproc. Unlink from parent's child list. 286 */ 287 LIST_REMOVE(p, p_list); 288 LIST_INSERT_HEAD(&zombproc, p, p_list); 289 p->p_stat = SZOMB; 290 291 LIST_REMOVE(p, p_hash); 292 293 q = LIST_FIRST(&p->p_children); 294 if (q) /* only need this if any child is S_ZOMB */ 295 wakeup((caddr_t) initproc); 296 for (; q != 0; q = nq) { 297 nq = LIST_NEXT(q, p_sibling); 298 LIST_REMOVE(q, p_sibling); 299 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling); 300 q->p_pptr = initproc; 301 q->p_sigparent = SIGCHLD; 302 /* 303 * Traced processes are killed 304 * since their existence means someone is screwing up. 305 */ 306 if (q->p_flag & P_TRACED) { 307 q->p_flag &= ~P_TRACED; 308 psignal(q, SIGKILL); 309 } 310 } 311 312 /* 313 * Save exit status and final rusage info, adding in child rusage 314 * info and self times. 315 */ 316 p->p_xstat = rv; 317 *p->p_ru = p->p_stats->p_ru; 318 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 319 ruadd(p->p_ru, &p->p_stats->p_cru); 320 321 /* 322 * Pretend that an mi_switch() to the next process occurs now. We 323 * must set `switchtime' directly since we will call cpu_switch() 324 * directly. Set it now so that the rest of the exit time gets 325 * counted somewhere if possible. 326 */ 327 microuptime(&switchtime); 328 switchticks = ticks; 329 330 /* 331 * notify interested parties of our demise. 332 */ 333 KNOTE(&p->p_klist, NOTE_EXIT); 334 335 /* 336 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 337 * flag set, notify process 1 instead (and hope it will handle 338 * this situation). 339 */ 340 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) { 341 struct proc *pp = p->p_pptr; 342 proc_reparent(p, initproc); 343 /* 344 * If this was the last child of our parent, notify 345 * parent, so in case he was wait(2)ing, he will 346 * continue. 347 */ 348 if (LIST_EMPTY(&pp->p_children)) 349 wakeup((caddr_t)pp); 350 } 351 352 if (p->p_sigparent && p->p_pptr != initproc) { 353 psignal(p->p_pptr, p->p_sigparent); 354 } else { 355 psignal(p->p_pptr, SIGCHLD); 356 } 357 358 wakeup((caddr_t)p->p_pptr); 359 #if defined(tahoe) 360 /* move this to cpu_exit */ 361 p->p_addr->u_pcb.pcb_savacc.faddr = (float *)NULL; 362 #endif 363 /* 364 * Clear curproc after we've done all operations 365 * that could block, and before tearing down the rest 366 * of the process state that might be used from clock, etc. 367 * Also, can't clear curproc while we're still runnable, 368 * as we're not on a run queue (we are current, just not 369 * a proper proc any longer!). 370 * 371 * Other substructures are freed from wait(). 372 */ 373 SET_CURPROC(NULL); 374 if (--p->p_limit->p_refcnt == 0) { 375 FREE(p->p_limit, M_SUBPROC); 376 p->p_limit = NULL; 377 } 378 379 /* 380 * Finally, call machine-dependent code to release the remaining 381 * resources including address space, the kernel stack and pcb. 382 * The address space is released by "vmspace_free(p->p_vmspace)"; 383 * This is machine-dependent, as we may have to change stacks 384 * or ensure that the current one isn't reallocated before we 385 * finish. cpu_exit will end with a call to cpu_switch(), finishing 386 * our execution (pun intended). 387 */ 388 cpu_exit(p); 389 } 390 391 #ifdef COMPAT_43 392 int 393 owait(p, uap) 394 struct proc *p; 395 register struct owait_args /* { 396 int dummy; 397 } */ *uap; 398 { 399 struct wait_args w; 400 401 w.options = 0; 402 w.rusage = NULL; 403 w.pid = WAIT_ANY; 404 w.status = NULL; 405 return (wait1(p, &w, 1)); 406 } 407 #endif /* COMPAT_43 */ 408 409 int 410 wait4(p, uap) 411 struct proc *p; 412 struct wait_args *uap; 413 { 414 415 return (wait1(p, uap, 0)); 416 } 417 418 static int 419 wait1(q, uap, compat) 420 register struct proc *q; 421 register struct wait_args /* { 422 int pid; 423 int *status; 424 int options; 425 struct rusage *rusage; 426 } */ *uap; 427 int compat; 428 { 429 register int nfound; 430 register struct proc *p, *t; 431 int status, error; 432 433 if (uap->pid == 0) 434 uap->pid = -q->p_pgid; 435 if (uap->options &~ (WUNTRACED|WNOHANG|WLINUXCLONE)) 436 return (EINVAL); 437 loop: 438 nfound = 0; 439 LIST_FOREACH(p, &q->p_children, p_sibling) { 440 if (uap->pid != WAIT_ANY && 441 p->p_pid != uap->pid && p->p_pgid != -uap->pid) 442 continue; 443 444 /* This special case handles a kthread spawned by linux_clone 445 * (see linux_misc.c). The linux_wait4 and linux_waitpid functions 446 * need to be able to distinguish between waiting on a process and 447 * waiting on a thread. It is a thread if p_sigparent is not SIGCHLD, 448 * and the WLINUXCLONE option signifies we want to wait for threads 449 * and not processes. 450 */ 451 if ((p->p_sigparent != SIGCHLD) ^ ((uap->options & WLINUXCLONE) != 0)) 452 continue; 453 454 nfound++; 455 if (p->p_stat == SZOMB) { 456 /* charge childs scheduling cpu usage to parent */ 457 if (curproc->p_pid != 1) { 458 curproc->p_estcpu = 459 ESTCPULIM(curproc->p_estcpu + p->p_estcpu); 460 } 461 462 q->p_retval[0] = p->p_pid; 463 #ifdef COMPAT_43 464 if (compat) 465 q->p_retval[1] = p->p_xstat; 466 else 467 #endif 468 if (uap->status) { 469 status = p->p_xstat; /* convert to int */ 470 if ((error = copyout((caddr_t)&status, 471 (caddr_t)uap->status, sizeof(status)))) 472 return (error); 473 } 474 if (uap->rusage && (error = copyout((caddr_t)p->p_ru, 475 (caddr_t)uap->rusage, sizeof (struct rusage)))) 476 return (error); 477 /* 478 * If we got the child via a ptrace 'attach', 479 * we need to give it back to the old parent. 480 */ 481 if (p->p_oppid && (t = pfind(p->p_oppid))) { 482 p->p_oppid = 0; 483 proc_reparent(p, t); 484 psignal(t, SIGCHLD); 485 wakeup((caddr_t)t); 486 return (0); 487 } 488 p->p_xstat = 0; 489 ruadd(&q->p_stats->p_cru, p->p_ru); 490 FREE(p->p_ru, M_ZOMBIE); 491 p->p_ru = NULL; 492 493 /* 494 * Decrement the count of procs running with this uid. 495 */ 496 (void)chgproccnt(p->p_cred->p_uidinfo, -1, 0); 497 498 /* 499 * Free up credentials. 500 */ 501 if (--p->p_cred->p_refcnt == 0) { 502 crfree(p->p_ucred); 503 uifree(p->p_cred->p_uidinfo); 504 FREE(p->p_cred, M_SUBPROC); 505 p->p_cred = NULL; 506 } 507 508 /* 509 * Destroy empty prisons 510 */ 511 if (p->p_prison && !--p->p_prison->pr_ref) { 512 if (p->p_prison->pr_linux != NULL) 513 FREE(p->p_prison->pr_linux, M_PRISON); 514 FREE(p->p_prison, M_PRISON); 515 } 516 517 /* 518 * Remove unused arguments 519 */ 520 if (p->p_args && --p->p_args->ar_ref == 0) 521 FREE(p->p_args, M_PARGS); 522 523 /* 524 * Finally finished with old proc entry. 525 * Unlink it from its process group and free it. 526 */ 527 leavepgrp(p); 528 LIST_REMOVE(p, p_list); /* off zombproc */ 529 LIST_REMOVE(p, p_sibling); 530 531 if (--p->p_procsig->ps_refcnt == 0) { 532 if (p->p_sigacts != &p->p_addr->u_sigacts) 533 FREE(p->p_sigacts, M_SUBPROC); 534 FREE(p->p_procsig, M_SUBPROC); 535 p->p_procsig = NULL; 536 } 537 538 /* 539 * Give machine-dependent layer a chance 540 * to free anything that cpu_exit couldn't 541 * release while still running in process context. 542 */ 543 vm_waitproc(p); 544 zfree(proc_zone, p); 545 nprocs--; 546 return (0); 547 } 548 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 549 (p->p_flag & P_TRACED || uap->options & WUNTRACED)) { 550 p->p_flag |= P_WAITED; 551 q->p_retval[0] = p->p_pid; 552 #ifdef COMPAT_43 553 if (compat) { 554 q->p_retval[1] = W_STOPCODE(p->p_xstat); 555 error = 0; 556 } else 557 #endif 558 if (uap->status) { 559 status = W_STOPCODE(p->p_xstat); 560 error = copyout((caddr_t)&status, 561 (caddr_t)uap->status, sizeof(status)); 562 } else 563 error = 0; 564 return (error); 565 } 566 } 567 if (nfound == 0) 568 return (ECHILD); 569 if (uap->options & WNOHANG) { 570 q->p_retval[0] = 0; 571 return (0); 572 } 573 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0))) 574 return (error); 575 goto loop; 576 } 577 578 /* 579 * make process 'parent' the new parent of process 'child'. 580 */ 581 void 582 proc_reparent(child, parent) 583 register struct proc *child; 584 register struct proc *parent; 585 { 586 587 if (child->p_pptr == parent) 588 return; 589 590 LIST_REMOVE(child, p_sibling); 591 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 592 child->p_pptr = parent; 593 } 594 595 /* 596 * The next two functions are to handle adding/deleting items on the 597 * exit callout list 598 * 599 * at_exit(): 600 * Take the arguments given and put them onto the exit callout list, 601 * However first make sure that it's not already there. 602 * returns 0 on success. 603 */ 604 605 int 606 at_exit(function) 607 exitlist_fn function; 608 { 609 struct exitlist *ep; 610 611 #ifdef INVARIANTS 612 /* Be noisy if the programmer has lost track of things */ 613 if (rm_at_exit(function)) 614 printf("WARNING: exit callout entry (%p) already present\n", 615 function); 616 #endif 617 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT); 618 if (ep == NULL) 619 return (ENOMEM); 620 ep->function = function; 621 TAILQ_INSERT_TAIL(&exit_list, ep, next); 622 return (0); 623 } 624 625 /* 626 * Scan the exit callout list for the given item and remove it. 627 * Returns the number of items removed (0 or 1) 628 */ 629 int 630 rm_at_exit(function) 631 exitlist_fn function; 632 { 633 struct exitlist *ep; 634 635 TAILQ_FOREACH(ep, &exit_list, next) { 636 if (ep->function == function) { 637 TAILQ_REMOVE(&exit_list, ep, next); 638 free(ep, M_ATEXIT); 639 return(1); 640 } 641 } 642 return (0); 643 } 644 645 void check_sigacts (void) 646 { 647 struct proc *p = curproc; 648 struct sigacts *pss; 649 int s; 650 651 if (p->p_procsig->ps_refcnt == 1 && 652 p->p_sigacts != &p->p_addr->u_sigacts) { 653 pss = p->p_sigacts; 654 s = splhigh(); 655 p->p_addr->u_sigacts = *pss; 656 p->p_sigacts = &p->p_addr->u_sigacts; 657 splx(s); 658 FREE(pss, M_SUBPROC); 659 } 660 } 661 662