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 1.47 2005/10/11 09:59:56 corecode 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 #include <sys/kern_syscall.h> 66 #include <sys/upcall.h> 67 #include <sys/caps.h> 68 69 #include <vm/vm.h> 70 #include <vm/vm_param.h> 71 #include <sys/lock.h> 72 #include <vm/pmap.h> 73 #include <vm/vm_map.h> 74 #include <vm/vm_zone.h> 75 #include <vm/vm_extern.h> 76 #include <sys/user.h> 77 78 #include <sys/thread2.h> 79 80 /* Required to be non-static for SysVR4 emulator */ 81 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); 82 83 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback"); 84 85 /* 86 * callout list for things to do at exit time 87 */ 88 struct exitlist { 89 exitlist_fn function; 90 TAILQ_ENTRY(exitlist) next; 91 }; 92 93 TAILQ_HEAD(exit_list_head, exitlist); 94 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list); 95 96 /* 97 * exit -- 98 * Death of process. 99 * 100 * SYS_EXIT_ARGS(int rval) 101 */ 102 void 103 sys_exit(struct sys_exit_args *uap) 104 { 105 exit1(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(int rv) 116 { 117 struct proc *p = curproc; 118 struct lwp *lp; 119 struct proc *q, *nq; 120 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 lp = &p->p_lwp; /* XXX lwp kill other threads */ 131 132 sysmsg_rundown(lp, 1); 133 caps_exit(lp->lwp_thread); 134 aio_proc_rundown(p); 135 136 /* are we a task leader? */ 137 if(p == p->p_leader) { 138 struct kill_args killArgs; 139 killArgs.signum = SIGKILL; 140 q = p->p_peers; 141 while(q) { 142 killArgs.pid = q->p_pid; 143 /* 144 * The interface for kill is better 145 * than the internal signal 146 */ 147 kill(&killArgs); 148 nq = q; 149 q = q->p_peers; 150 } 151 while (p->p_peers) 152 tsleep((caddr_t)p, 0, "exit1", 0); 153 } 154 155 #ifdef PGINPROF 156 vmsizmon(); 157 #endif 158 STOPEVENT(p, S_EXIT, rv); 159 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ 160 161 /* 162 * Check if any loadable modules need anything done at process exit. 163 * e.g. SYSV IPC stuff 164 * XXX what if one of these generates an error? 165 */ 166 TAILQ_FOREACH(ep, &exit_list, next) 167 (*ep->function)(p->p_thread); 168 169 if (p->p_flag & P_PROFIL) 170 stopprofclock(p); 171 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 172 M_ZOMBIE, M_WAITOK); 173 /* 174 * If parent is waiting for us to exit or exec, 175 * P_PPWAIT is set; we will wakeup the parent below. 176 */ 177 p->p_flag &= ~(P_TRACED | P_PPWAIT); 178 p->p_flag |= P_WEXIT; 179 SIGEMPTYSET(p->p_siglist); 180 if (timevalisset(&p->p_realtimer.it_value)) 181 callout_stop(&p->p_ithandle); 182 183 /* 184 * Reset any sigio structures pointing to us as a result of 185 * F_SETOWN with our pid. 186 */ 187 funsetownlst(&p->p_sigiolst); 188 189 /* 190 * Close open files and release open-file table. 191 * This may block! 192 */ 193 fdfree(p); 194 p->p_fd = NULL; 195 196 if(p->p_leader->p_peers) { 197 q = p->p_leader; 198 while(q->p_peers != p) 199 q = q->p_peers; 200 q->p_peers = p->p_peers; 201 wakeup((caddr_t)p->p_leader); 202 } 203 204 /* 205 * XXX Shutdown SYSV semaphores 206 */ 207 semexit(p); 208 209 KKASSERT(p->p_numposixlocks == 0); 210 211 /* The next two chunks should probably be moved to vmspace_exit. */ 212 vm = p->p_vmspace; 213 214 /* 215 * Release upcalls associated with this process 216 */ 217 if (vm->vm_upcalls) 218 upc_release(vm, &p->p_lwp); 219 220 /* 221 * Release user portion of address space. 222 * This releases references to vnodes, 223 * which could cause I/O if the file has been unlinked. 224 * Need to do this early enough that we can still sleep. 225 * Can't free the entire vmspace as the kernel stack 226 * may be mapped within that space also. 227 * 228 * Processes sharing the same vmspace may exit in one order, and 229 * get cleaned up by vmspace_exit() in a different order. The 230 * last exiting process to reach this point releases as much of 231 * the environment as it can, and the last process cleaned up 232 * by vmspace_exit() (which decrements exitingcnt) cleans up the 233 * remainder. 234 */ 235 ++vm->vm_exitingcnt; 236 if (--vm->vm_refcnt == 0) { 237 shmexit(vm); 238 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS, 239 VM_MAXUSER_ADDRESS); 240 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS, 241 VM_MAXUSER_ADDRESS); 242 } 243 244 if (SESS_LEADER(p)) { 245 struct session *sp = p->p_session; 246 struct vnode *vp; 247 248 if (sp->s_ttyvp) { 249 /* 250 * We are the controlling process. Signal the 251 * foreground process group, drain the controlling 252 * terminal, and revoke access to the controlling 253 * terminal. 254 * 255 * NOTE: while waiting for the process group to exit 256 * it is possible that one of the processes in the 257 * group will revoke the tty, so we have to recheck. 258 */ 259 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 260 if (sp->s_ttyp->t_pgrp) 261 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 262 (void) ttywait(sp->s_ttyp); 263 /* 264 * The tty could have been revoked 265 * if we blocked. 266 */ 267 if ((vp = sp->s_ttyvp) != NULL) { 268 ttyclosesession(sp, 0); 269 if (vx_lock(vp) == 0) { 270 VOP_REVOKE(vp, REVOKEALL); 271 vx_unlock(vp); 272 } 273 vrele(vp); /* s_ttyvp ref */ 274 } 275 } 276 /* 277 * Release the tty. If someone has it open via 278 * /dev/tty then close it (since they no longer can 279 * once we've NULL'd it out). 280 */ 281 if (sp->s_ttyvp) 282 ttyclosesession(sp, 1); 283 /* 284 * s_ttyp is not zero'd; we use this to indicate 285 * that the session once had a controlling terminal. 286 * (for logging and informational purposes) 287 */ 288 } 289 sp->s_leader = NULL; 290 } 291 fixjobc(p, p->p_pgrp, 0); 292 (void)acct_process(p); 293 #ifdef KTRACE 294 /* 295 * release trace file 296 */ 297 p->p_traceflag = 0; /* don't trace the vrele() */ 298 if ((vtmp = p->p_tracep) != NULL) { 299 p->p_tracep = NULL; 300 vrele(vtmp); 301 } 302 #endif 303 /* 304 * Release reference to text vnode 305 */ 306 if ((vtmp = p->p_textvp) != NULL) { 307 p->p_textvp = NULL; 308 vrele(vtmp); 309 } 310 311 /* 312 * Once we set SZOMB the process can get reaped. The wait1 code 313 * will also wait for TDF_RUNNING to be cleared in the thread's flags, 314 * indicating that it has been completely switched out. 315 */ 316 317 /* 318 * Remove proc from allproc queue and pidhash chain. 319 * Place onto zombproc. Unlink from parent's child list. 320 */ 321 LIST_REMOVE(p, p_list); 322 LIST_INSERT_HEAD(&zombproc, p, p_list); 323 p->p_stat = SZOMB; 324 325 LIST_REMOVE(p, p_hash); 326 327 q = LIST_FIRST(&p->p_children); 328 if (q) /* only need this if any child is S_ZOMB */ 329 wakeup((caddr_t) initproc); 330 for (; q != 0; q = nq) { 331 nq = LIST_NEXT(q, p_sibling); 332 LIST_REMOVE(q, p_sibling); 333 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling); 334 q->p_pptr = initproc; 335 q->p_sigparent = SIGCHLD; 336 /* 337 * Traced processes are killed 338 * since their existence means someone is screwing up. 339 */ 340 if (q->p_flag & P_TRACED) { 341 q->p_flag &= ~P_TRACED; 342 psignal(q, SIGKILL); 343 } 344 } 345 346 /* 347 * Save exit status and final rusage info, adding in child rusage 348 * info and self times. 349 */ 350 p->p_xstat = rv; 351 *p->p_ru = p->p_stats->p_ru; 352 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 353 ruadd(p->p_ru, &p->p_stats->p_cru); 354 355 /* 356 * notify interested parties of our demise. 357 */ 358 KNOTE(&p->p_klist, NOTE_EXIT); 359 360 /* 361 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT 362 * flag set, notify process 1 instead (and hope it will handle 363 * this situation). 364 */ 365 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) { 366 struct proc *pp = p->p_pptr; 367 proc_reparent(p, initproc); 368 /* 369 * If this was the last child of our parent, notify 370 * parent, so in case he was wait(2)ing, he will 371 * continue. 372 */ 373 if (LIST_EMPTY(&pp->p_children)) 374 wakeup((caddr_t)pp); 375 } 376 377 if (p->p_sigparent && p->p_pptr != initproc) { 378 psignal(p->p_pptr, p->p_sigparent); 379 } else { 380 psignal(p->p_pptr, SIGCHLD); 381 } 382 383 wakeup((caddr_t)p->p_pptr); 384 /* 385 * cpu_exit is responsible for clearing curproc, since 386 * it is heavily integrated with the thread/switching sequence. 387 * 388 * Other substructures are freed from wait(). 389 */ 390 if (--p->p_limit->p_refcnt == 0) { 391 FREE(p->p_limit, M_SUBPROC); 392 p->p_limit = NULL; 393 } 394 395 /* 396 * Release the current user process designation on the process so 397 * the userland scheduler can work in someone else. 398 */ 399 p->p_usched->release_curproc(lp); 400 401 /* 402 * Finally, call machine-dependent code to release the remaining 403 * resources including address space, the kernel stack and pcb. 404 * The address space is released by "vmspace_free(p->p_vmspace)"; 405 * This is machine-dependent, as we may have to change stacks 406 * or ensure that the current one isn't reallocated before we 407 * finish. cpu_exit will end with a call to cpu_switch(), finishing 408 * our execution (pun intended). 409 */ 410 cpu_proc_exit(); 411 } 412 413 int 414 wait4(struct wait_args *uap) 415 { 416 struct rusage rusage; 417 int error, status; 418 419 error = kern_wait(uap->pid, uap->status ? &status : NULL, 420 uap->options, uap->rusage ? &rusage : NULL, &uap->sysmsg_fds[0]); 421 422 if (error == 0 && uap->status) 423 error = copyout(&status, uap->status, sizeof(*uap->status)); 424 if (error == 0 && uap->rusage) 425 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage)); 426 return (error); 427 } 428 429 /* 430 * wait1() 431 * 432 * wait_args(int pid, int *status, int options, struct rusage *rusage) 433 */ 434 int 435 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res) 436 { 437 struct thread *td = curthread; 438 struct proc *q = td->td_proc; 439 struct proc *p, *t; 440 int nfound, error; 441 442 if (pid == 0) 443 pid = -q->p_pgid; 444 if (options &~ (WUNTRACED|WNOHANG|WLINUXCLONE)) 445 return (EINVAL); 446 loop: 447 nfound = 0; 448 LIST_FOREACH(p, &q->p_children, p_sibling) { 449 if (pid != WAIT_ANY && 450 p->p_pid != pid && p->p_pgid != -pid) 451 continue; 452 453 /* This special case handles a kthread spawned by linux_clone 454 * (see linux_misc.c). The linux_wait4 and linux_waitpid 455 * functions need to be able to distinguish between waiting 456 * on a process and waiting on a thread. It is a thread if 457 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option 458 * signifies we want to wait for threads and not processes. 459 */ 460 if ((p->p_sigparent != SIGCHLD) ^ 461 ((options & WLINUXCLONE) != 0)) { 462 continue; 463 } 464 465 nfound++; 466 if (p->p_stat == SZOMB) { 467 /* 468 * The process's thread may still be in the middle 469 * of switching away, we can't rip its stack out from 470 * under it until TDF_RUNNING clears! 471 * 472 * YYY no wakeup occurs so we depend on the timeout. 473 */ 474 if ((p->p_thread->td_flags & TDF_RUNNING) != 0) { 475 tsleep(p->p_thread, 0, "reap", 1); 476 goto loop; 477 } 478 479 /* 480 * Other kernel threads may be in the middle of 481 * accessing the proc. For example, kern/kern_proc.c 482 * could be blocked writing proc data to a sysctl. 483 * At the moment, if this occurs, we are not woken 484 * up and rely on a one-second retry. 485 */ 486 if (p->p_lock) { 487 while (p->p_lock) 488 tsleep(p, 0, "reap2", hz); 489 } 490 lwkt_wait_free(p->p_thread); 491 492 /* scheduling hook for heuristic */ 493 p->p_usched->heuristic_exiting(td->td_lwp, &p->p_lwp); 494 495 /* Take care of our return values. */ 496 *res = p->p_pid; 497 if (status) 498 *status = p->p_xstat; 499 if (rusage) 500 *rusage = *p->p_ru; 501 /* 502 * If we got the child via a ptrace 'attach', 503 * we need to give it back to the old parent. 504 */ 505 if (p->p_oppid && (t = pfind(p->p_oppid))) { 506 p->p_oppid = 0; 507 proc_reparent(p, t); 508 psignal(t, SIGCHLD); 509 wakeup((caddr_t)t); 510 return (0); 511 } 512 p->p_xstat = 0; 513 ruadd(&q->p_stats->p_cru, p->p_ru); 514 FREE(p->p_ru, M_ZOMBIE); 515 p->p_ru = NULL; 516 517 /* 518 * Decrement the count of procs running with this uid. 519 */ 520 chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); 521 522 /* 523 * Free up credentials. 524 */ 525 crfree(p->p_ucred); 526 p->p_ucred = NULL; 527 528 /* 529 * Remove unused arguments 530 */ 531 if (p->p_args && --p->p_args->ar_ref == 0) 532 FREE(p->p_args, M_PARGS); 533 534 /* 535 * Finally finished with old proc entry. 536 * Unlink it from its process group and free it. 537 */ 538 leavepgrp(p); 539 LIST_REMOVE(p, p_list); /* off zombproc */ 540 LIST_REMOVE(p, p_sibling); 541 542 if (--p->p_procsig->ps_refcnt == 0) { 543 if (p->p_sigacts != &p->p_addr->u_sigacts) 544 FREE(p->p_sigacts, M_SUBPROC); 545 FREE(p->p_procsig, M_SUBPROC); 546 p->p_procsig = NULL; 547 } 548 549 vm_waitproc(p); 550 zfree(proc_zone, p); 551 nprocs--; 552 return (0); 553 } 554 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 555 (p->p_flag & P_TRACED || options & WUNTRACED)) { 556 p->p_flag |= P_WAITED; 557 558 *res = p->p_pid; 559 if (status) 560 *status = W_STOPCODE(p->p_xstat); 561 /* Zero rusage so we get something consistent. */ 562 if (rusage) 563 bzero(rusage, sizeof(rusage)); 564 return (0); 565 } 566 } 567 if (nfound == 0) 568 return (ECHILD); 569 if (options & WNOHANG) { 570 *res = 0; 571 return (0); 572 } 573 error = tsleep((caddr_t)q, PCATCH, "wait", 0); 574 if (error) 575 return (error); 576 goto loop; 577 } 578 579 /* 580 * make process 'parent' the new parent of process 'child'. 581 */ 582 void 583 proc_reparent(struct proc *child, 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(exitlist_fn function) 606 { 607 struct exitlist *ep; 608 609 #ifdef INVARIANTS 610 /* Be noisy if the programmer has lost track of things */ 611 if (rm_at_exit(function)) 612 printf("WARNING: exit callout entry (%p) already present\n", 613 function); 614 #endif 615 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT); 616 if (ep == NULL) 617 return (ENOMEM); 618 ep->function = function; 619 TAILQ_INSERT_TAIL(&exit_list, ep, next); 620 return (0); 621 } 622 623 /* 624 * Scan the exit callout list for the given item and remove it. 625 * Returns the number of items removed (0 or 1) 626 */ 627 int 628 rm_at_exit(exitlist_fn function) 629 { 630 struct exitlist *ep; 631 632 TAILQ_FOREACH(ep, &exit_list, next) { 633 if (ep->function == function) { 634 TAILQ_REMOVE(&exit_list, ep, next); 635 free(ep, M_ATEXIT); 636 return(1); 637 } 638 } 639 return (0); 640 } 641 642 void 643 check_sigacts(void) 644 { 645 struct proc *p = curproc; 646 struct sigacts *pss; 647 648 if (p->p_procsig->ps_refcnt == 1 && 649 p->p_sigacts != &p->p_addr->u_sigacts) { 650 pss = p->p_sigacts; 651 crit_enter(); 652 p->p_addr->u_sigacts = *pss; 653 p->p_sigacts = &p->p_addr->u_sigacts; 654 crit_exit(); 655 FREE(pss, M_SUBPROC); 656 } 657 } 658 659