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