1 /* $NetBSD: kern_exit.c,v 1.101 2002/09/04 01:32:32 matt Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1989, 1991, 1993 42 * The Regents of the University of California. All rights reserved. 43 * (c) UNIX System Laboratories, Inc. 44 * All or some portions of this file are derived from material licensed 45 * to the University of California by American Telephone and Telegraph 46 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 47 * the permission of UNIX System Laboratories, Inc. 48 * 49 * Redistribution and use in source and binary forms, with or without 50 * modification, are permitted provided that the following conditions 51 * are met: 52 * 1. Redistributions of source code must retain the above copyright 53 * notice, this list of conditions and the following disclaimer. 54 * 2. Redistributions in binary form must reproduce the above copyright 55 * notice, this list of conditions and the following disclaimer in the 56 * documentation and/or other materials provided with the distribution. 57 * 3. All advertising materials mentioning features or use of this software 58 * must display the following acknowledgement: 59 * This product includes software developed by the University of 60 * California, Berkeley and its contributors. 61 * 4. Neither the name of the University nor the names of its contributors 62 * may be used to endorse or promote products derived from this software 63 * without specific prior written permission. 64 * 65 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 66 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 67 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 68 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 69 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 70 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 71 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 72 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 73 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 74 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 75 * SUCH DAMAGE. 76 * 77 * @(#)kern_exit.c 8.10 (Berkeley) 2/23/95 78 */ 79 80 #include <sys/cdefs.h> 81 __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.101 2002/09/04 01:32:32 matt Exp $"); 82 83 #include "opt_ktrace.h" 84 #include "opt_perfctrs.h" 85 #include "opt_systrace.h" 86 #include "opt_sysv.h" 87 88 #include <sys/param.h> 89 #include <sys/systm.h> 90 #include <sys/map.h> 91 #include <sys/ioctl.h> 92 #include <sys/proc.h> 93 #include <sys/tty.h> 94 #include <sys/time.h> 95 #include <sys/resource.h> 96 #include <sys/kernel.h> 97 #include <sys/ktrace.h> 98 #include <sys/proc.h> 99 #include <sys/buf.h> 100 #include <sys/wait.h> 101 #include <sys/file.h> 102 #include <sys/vnode.h> 103 #include <sys/syslog.h> 104 #include <sys/malloc.h> 105 #include <sys/pool.h> 106 #include <sys/resourcevar.h> 107 #if defined(PERFCTRS) 108 #include <sys/pmc.h> 109 #endif 110 #include <sys/ptrace.h> 111 #include <sys/acct.h> 112 #include <sys/filedesc.h> 113 #include <sys/ras.h> 114 #include <sys/signalvar.h> 115 #include <sys/sched.h> 116 #include <sys/mount.h> 117 #include <sys/syscallargs.h> 118 #include <sys/systrace.h> 119 120 #include <machine/cpu.h> 121 122 #include <uvm/uvm_extern.h> 123 124 125 /* 126 * exit -- 127 * Death of process. 128 */ 129 int 130 sys_exit(struct proc *p, void *v, register_t *retval) 131 { 132 struct sys_exit_args /* { 133 syscallarg(int) rval; 134 } */ *uap = v; 135 136 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 137 /* NOTREACHED */ 138 return (0); 139 } 140 141 /* 142 * Exit: deallocate address space and other resources, change proc state 143 * to zombie, and unlink proc from allproc and parent's lists. Save exit 144 * status and rusage for wait(). Check for child processes and orphan them. 145 */ 146 void 147 exit1(struct proc *p, int rv) 148 { 149 struct proc *q, *nq; 150 int s; 151 152 if (__predict_false(p == initproc)) 153 panic("init died (signal %d, exit %d)", 154 WTERMSIG(rv), WEXITSTATUS(rv)); 155 156 #ifdef PGINPROF 157 vmsizmon(); 158 #endif 159 if (p->p_flag & P_PROFIL) 160 stopprofclock(p); 161 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 162 /* 163 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 164 * wake up the parent early to avoid deadlock. 165 */ 166 p->p_flag |= P_WEXIT; 167 if (p->p_flag & P_PPWAIT) { 168 p->p_flag &= ~P_PPWAIT; 169 wakeup((caddr_t)p->p_pptr); 170 } 171 sigfillset(&p->p_sigctx.ps_sigignore); 172 sigemptyset(&p->p_sigctx.ps_siglist); 173 p->p_sigctx.ps_sigcheck = 0; 174 callout_stop(&p->p_realit_ch); 175 176 #if defined(__HAVE_RAS) 177 ras_purgeall(p); 178 #endif 179 180 /* 181 * Close open files and release open-file table. 182 * This may block! 183 */ 184 fdfree(p); 185 cwdfree(p); 186 187 doexithooks(p); 188 189 if (SESS_LEADER(p)) { 190 struct session *sp = p->p_session; 191 192 if (sp->s_ttyvp) { 193 /* 194 * Controlling process. 195 * Signal foreground pgrp, 196 * drain controlling terminal 197 * and revoke access to controlling terminal. 198 */ 199 if (sp->s_ttyp->t_session == sp) { 200 if (sp->s_ttyp->t_pgrp) 201 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 202 (void) ttywait(sp->s_ttyp); 203 /* 204 * The tty could have been revoked 205 * if we blocked. 206 */ 207 if (sp->s_ttyvp) 208 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 209 } 210 if (sp->s_ttyvp) 211 vrele(sp->s_ttyvp); 212 sp->s_ttyvp = NULL; 213 /* 214 * s_ttyp is not zero'd; we use this to indicate 215 * that the session once had a controlling terminal. 216 * (for logging and informational purposes) 217 */ 218 } 219 sp->s_leader = NULL; 220 } 221 fixjobc(p, p->p_pgrp, 0); 222 (void)acct_process(p); 223 #ifdef KTRACE 224 /* 225 * release trace file 226 */ 227 ktrderef(p); 228 #endif 229 #ifdef SYSTRACE 230 systrace_sys_exit(p); 231 #endif 232 /* 233 * If emulation has process exit hook, call it now. 234 */ 235 if (p->p_emul->e_proc_exit) 236 (*p->p_emul->e_proc_exit)(p); 237 238 /* 239 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 240 */ 241 p->p_stat = SDEAD; 242 243 /* 244 * Remove proc from pidhash chain so looking it up won't 245 * work. Move it from allproc to zombproc, but do not yet 246 * wake up the reaper. We will put the proc on the 247 * deadproc list later (using the p_hash member), and 248 * wake up the reaper when we do. 249 */ 250 s = proclist_lock_write(); 251 LIST_REMOVE(p, p_hash); 252 LIST_REMOVE(p, p_list); 253 LIST_INSERT_HEAD(&zombproc, p, p_list); 254 proclist_unlock_write(s); 255 256 /* 257 * Give orphaned children to init(8). 258 */ 259 q = LIST_FIRST(&p->p_children); 260 if (q) /* only need this if any child is S_ZOMB */ 261 wakeup((caddr_t)initproc); 262 for (; q != 0; q = nq) { 263 nq = LIST_NEXT(q, p_sibling); 264 proc_reparent(q, initproc); 265 /* 266 * Traced processes are killed 267 * since their existence means someone is screwing up. 268 */ 269 if (q->p_flag & P_TRACED) { 270 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 271 psignal(q, SIGKILL); 272 } 273 } 274 275 /* 276 * Reset p_opptr pointer of all former children which got 277 * traced by another process and were reparented. We reset 278 * it to NULL here; the trace detach code then reparents 279 * the child to initproc. We only check allproc list, since 280 * eventual former children on zombproc list won't reference 281 * p_opptr anymore. 282 */ 283 if (p->p_flag & P_CHTRACED) { 284 struct proc *t; 285 286 proclist_lock_read(); 287 288 LIST_FOREACH(t, &allproc, p_list) { 289 if (t->p_opptr == p) 290 t->p_opptr = NULL; 291 } 292 293 proclist_unlock_read(); 294 } 295 296 /* 297 * Save exit status and final rusage info, adding in child rusage 298 * info and self times. 299 */ 300 p->p_xstat = rv; 301 *p->p_ru = p->p_stats->p_ru; 302 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 303 ruadd(p->p_ru, &p->p_stats->p_cru); 304 305 #if PERFCTRS 306 /* 307 * Save final PMC information in parent process & clean up. 308 */ 309 if (PMC_ENABLED(p)) { 310 pmc_save_context(p); 311 pmc_accumulate(p->p_pptr, p); 312 pmc_process_exit(p); 313 } 314 #endif 315 316 /* 317 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 318 * flag set, notify init instead (and hope it will handle 319 * this situation). 320 */ 321 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 322 struct proc *pp = p->p_pptr; 323 proc_reparent(p, initproc); 324 /* 325 * If this was the last child of our parent, notify 326 * parent, so in case he was wait(2)ing, he will 327 * continue. 328 */ 329 if (LIST_FIRST(&pp->p_children) == NULL) 330 wakeup((caddr_t)pp); 331 } 332 333 /* 334 * Release the process's signal state. 335 */ 336 sigactsfree(p); 337 338 /* 339 * Clear curproc after we've done all operations 340 * that could block, and before tearing down the rest 341 * of the process state that might be used from clock, etc. 342 * Also, can't clear curproc while we're still runnable, 343 * as we're not on a run queue (we are current, just not 344 * a proper proc any longer!). 345 * 346 * Other substructures are freed from wait(). 347 */ 348 curproc = NULL; 349 limfree(p->p_limit); 350 p->p_limit = NULL; 351 352 /* This process no longer needs to hold the kernel lock. */ 353 KERNEL_PROC_UNLOCK(p); 354 355 /* 356 * Finally, call machine-dependent code to switch to a new 357 * context (possibly the idle context). Once we are no longer 358 * using the dead process's vmspace and stack, exit2() will be 359 * called to schedule those resources to be released by the 360 * reaper thread. 361 * 362 * Note that cpu_exit() will end with a call equivalent to 363 * cpu_switch(), finishing our execution (pun intended). 364 */ 365 cpu_exit(p); 366 } 367 368 /* 369 * We are called from cpu_exit() once it is safe to schedule the 370 * dead process's resources to be freed (i.e., once we've switched to 371 * the idle PCB for the current CPU). 372 * 373 * NOTE: One must be careful with locking in this routine. It's 374 * called from a critical section in machine-dependent code, so 375 * we should refrain from changing any interrupt state. 376 * 377 * We lock the deadproc list (a spin lock), place the proc on that 378 * list (using the p_hash member), and wake up the reaper. 379 */ 380 void 381 exit2(struct proc *p) 382 { 383 384 simple_lock(&deadproc_slock); 385 LIST_INSERT_HEAD(&deadproc, p, p_hash); 386 simple_unlock(&deadproc_slock); 387 388 wakeup(&deadproc); 389 } 390 391 /* 392 * Process reaper. This is run by a kernel thread to free the resources 393 * of a dead process. Once the resources are free, the process becomes 394 * a zombie, and the parent is allowed to read the undead's status. 395 */ 396 void 397 reaper(void *arg) 398 { 399 struct proc *p; 400 401 KERNEL_PROC_UNLOCK(curproc); 402 403 for (;;) { 404 simple_lock(&deadproc_slock); 405 p = LIST_FIRST(&deadproc); 406 if (p == NULL) { 407 /* No work for us; go to sleep until someone exits. */ 408 (void) ltsleep(&deadproc, PVM|PNORELOCK, 409 "reaper", 0, &deadproc_slock); 410 continue; 411 } 412 413 /* Remove us from the deadproc list. */ 414 LIST_REMOVE(p, p_hash); 415 simple_unlock(&deadproc_slock); 416 KERNEL_PROC_LOCK(curproc); 417 418 /* 419 * Give machine-dependent code a chance to free any 420 * resources it couldn't free while still running on 421 * that process's context. This must be done before 422 * uvm_exit(), in case these resources are in the PCB. 423 */ 424 cpu_wait(p); 425 426 /* 427 * Free the VM resources we're still holding on to. 428 * We must do this from a valid thread because doing 429 * so may block. 430 */ 431 uvm_exit(p); 432 433 /* Process is now a true zombie. */ 434 p->p_stat = SZOMB; 435 436 /* Wake up the parent so it can get exit status. */ 437 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 438 psignal(p->p_pptr, P_EXITSIG(p)); 439 KERNEL_PROC_UNLOCK(curproc); 440 wakeup((caddr_t)p->p_pptr); 441 } 442 } 443 444 int 445 sys_wait4(struct proc *q, void *v, register_t *retval) 446 { 447 struct sys_wait4_args /* { 448 syscallarg(int) pid; 449 syscallarg(int *) status; 450 syscallarg(int) options; 451 syscallarg(struct rusage *) rusage; 452 } */ *uap = v; 453 struct proc *p, *t; 454 int nfound, status, error, s; 455 456 if (SCARG(uap, pid) == 0) 457 SCARG(uap, pid) = -q->p_pgid; 458 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG)) 459 return (EINVAL); 460 461 loop: 462 nfound = 0; 463 LIST_FOREACH(p, &q->p_children, p_sibling) { 464 if (SCARG(uap, pid) != WAIT_ANY && 465 p->p_pid != SCARG(uap, pid) && 466 p->p_pgid != -SCARG(uap, pid)) 467 continue; 468 /* 469 * Wait for processes with p_exitsig != SIGCHLD processes only 470 * if WALTSIG is set; wait for processes with p_exitsig == 471 * SIGCHLD only if WALTSIG is clear. 472 */ 473 if (((SCARG(uap, options) & WALLSIG) == 0) && 474 ((SCARG(uap, options) & WALTSIG) ? 475 (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD))) 476 continue; 477 478 nfound++; 479 if (p->p_stat == SZOMB) { 480 retval[0] = p->p_pid; 481 482 if (SCARG(uap, status)) { 483 status = p->p_xstat; /* convert to int */ 484 error = copyout((caddr_t)&status, 485 (caddr_t)SCARG(uap, status), 486 sizeof(status)); 487 if (error) 488 return (error); 489 } 490 if (SCARG(uap, rusage) && 491 (error = copyout((caddr_t)p->p_ru, 492 (caddr_t)SCARG(uap, rusage), 493 sizeof(struct rusage)))) 494 return (error); 495 /* 496 * If we got the child via ptrace(2) or procfs, and 497 * the parent is different (meaning the process was 498 * attached, rather than run as a child), then we need 499 * to give it back to the old parent, and send the 500 * parent the exit signal. The rest of the cleanup 501 * will be done when the old parent waits on the child. 502 */ 503 if ((p->p_flag & P_TRACED) && p->p_opptr != p->p_pptr){ 504 t = p->p_opptr; 505 proc_reparent(p, t ? t : initproc); 506 p->p_opptr = NULL; 507 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 508 if (p->p_exitsig != 0) 509 psignal(p->p_pptr, P_EXITSIG(p)); 510 wakeup((caddr_t)p->p_pptr); 511 return (0); 512 } 513 scheduler_wait_hook(q, p); 514 p->p_xstat = 0; 515 ruadd(&q->p_stats->p_cru, p->p_ru); 516 pool_put(&rusage_pool, p->p_ru); 517 518 /* 519 * Finally finished with old proc entry. 520 * Unlink it from its process group and free it. 521 */ 522 leavepgrp(p); 523 524 s = proclist_lock_write(); 525 LIST_REMOVE(p, p_list); /* off zombproc */ 526 proclist_unlock_write(s); 527 528 LIST_REMOVE(p, p_sibling); 529 530 /* 531 * Decrement the count of procs running with this uid. 532 */ 533 (void)chgproccnt(p->p_cred->p_ruid, -1); 534 535 /* 536 * Free up credentials. 537 */ 538 if (--p->p_cred->p_refcnt == 0) { 539 crfree(p->p_cred->pc_ucred); 540 pool_put(&pcred_pool, p->p_cred); 541 } 542 543 /* 544 * Release reference to text vnode 545 */ 546 if (p->p_textvp) 547 vrele(p->p_textvp); 548 549 pool_put(&proc_pool, p); 550 nprocs--; 551 return (0); 552 } 553 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 554 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 555 p->p_flag |= P_WAITED; 556 retval[0] = p->p_pid; 557 558 if (SCARG(uap, status)) { 559 status = W_STOPCODE(p->p_xstat); 560 error = copyout((caddr_t)&status, 561 (caddr_t)SCARG(uap, status), 562 sizeof(status)); 563 } else 564 error = 0; 565 return (error); 566 } 567 } 568 if (nfound == 0) 569 return (ECHILD); 570 if (SCARG(uap, options) & WNOHANG) { 571 retval[0] = 0; 572 return (0); 573 } 574 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 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 if (parent == initproc) 590 child->p_exitsig = SIGCHLD; 591 592 LIST_REMOVE(child, p_sibling); 593 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 594 child->p_pptr = parent; 595 } 596