1 /* $NetBSD: kern_exit.c,v 1.79 2000/05/27 00:11:12 sommerfeld 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 "opt_ktrace.h" 81 #include "opt_sysv.h" 82 83 #include <sys/param.h> 84 #include <sys/systm.h> 85 #include <sys/map.h> 86 #include <sys/ioctl.h> 87 #include <sys/proc.h> 88 #include <sys/tty.h> 89 #include <sys/time.h> 90 #include <sys/resource.h> 91 #include <sys/kernel.h> 92 #include <sys/ktrace.h> 93 #include <sys/proc.h> 94 #include <sys/buf.h> 95 #include <sys/wait.h> 96 #include <sys/file.h> 97 #include <sys/vnode.h> 98 #include <sys/syslog.h> 99 #include <sys/malloc.h> 100 #include <sys/pool.h> 101 #include <sys/resourcevar.h> 102 #include <sys/ptrace.h> 103 #include <sys/acct.h> 104 #include <sys/filedesc.h> 105 #include <sys/signalvar.h> 106 #include <sys/sched.h> 107 #ifdef SYSVSHM 108 #include <sys/shm.h> 109 #endif 110 #ifdef SYSVSEM 111 #include <sys/sem.h> 112 #endif 113 114 #include <sys/mount.h> 115 #include <sys/syscallargs.h> 116 117 #include <machine/cpu.h> 118 119 #include <vm/vm.h> 120 #include <vm/vm_kern.h> 121 122 #include <uvm/uvm_extern.h> 123 124 /* 125 * exit -- 126 * Death of process. 127 */ 128 int 129 sys_exit(p, v, retval) 130 struct proc *p; 131 void *v; 132 register_t *retval; 133 { 134 struct sys_exit_args /* { 135 syscallarg(int) rval; 136 } */ *uap = v; 137 138 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 139 /* NOTREACHED */ 140 return (0); 141 } 142 143 /* 144 * Exit: deallocate address space and other resources, change proc state 145 * to zombie, and unlink proc from allproc and parent's lists. Save exit 146 * status and rusage for wait(). Check for child processes and orphan them. 147 */ 148 void 149 exit1(p, rv) 150 struct proc *p; 151 int rv; 152 { 153 struct proc *q, *nq; 154 struct vmspace *vm; 155 int s; 156 157 if (__predict_false(p == initproc)) 158 panic("init died (signal %d, exit %d)", 159 WTERMSIG(rv), WEXITSTATUS(rv)); 160 161 #ifdef PGINPROF 162 vmsizmon(); 163 #endif 164 if (p->p_flag & P_PROFIL) 165 stopprofclock(p); 166 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 167 /* 168 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 169 * wake up the parent early to avoid deadlock. 170 */ 171 p->p_flag |= P_WEXIT; 172 if (p->p_flag & P_PPWAIT) { 173 p->p_flag &= ~P_PPWAIT; 174 wakeup((caddr_t)p->p_pptr); 175 } 176 sigfillset(&p->p_sigignore); 177 sigemptyset(&p->p_siglist); 178 p->p_sigcheck = 0; 179 callout_stop(&p->p_realit_ch); 180 181 /* 182 * Close open files and release open-file table. 183 * This may block! 184 */ 185 fdfree(p); 186 cwdfree(p); 187 188 /* The next three chunks should probably be moved to vmspace_exit. */ 189 vm = p->p_vmspace; 190 #ifdef SYSVSHM 191 if (vm->vm_shm && vm->vm_refcnt == 1) 192 shmexit(vm); 193 #endif 194 #ifdef SYSVSEM 195 semexit(p); 196 #endif 197 /* 198 * Release user portion of address space. 199 * This releases references to vnodes, 200 * which could cause I/O if the file has been unlinked. 201 * Need to do this early enough that we can still sleep. 202 * Can't free the entire vmspace as the kernel stack 203 * may be mapped within that space also. 204 */ 205 if (vm->vm_refcnt == 1) 206 (void) uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 207 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 208 209 if (SESS_LEADER(p)) { 210 struct session *sp = p->p_session; 211 212 if (sp->s_ttyvp) { 213 /* 214 * Controlling process. 215 * Signal foreground pgrp, 216 * drain controlling terminal 217 * and revoke access to controlling terminal. 218 */ 219 if (sp->s_ttyp->t_session == sp) { 220 if (sp->s_ttyp->t_pgrp) 221 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 222 (void) ttywait(sp->s_ttyp); 223 /* 224 * The tty could have been revoked 225 * if we blocked. 226 */ 227 if (sp->s_ttyvp) 228 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 229 } 230 if (sp->s_ttyvp) 231 vrele(sp->s_ttyvp); 232 sp->s_ttyvp = NULL; 233 /* 234 * s_ttyp is not zero'd; we use this to indicate 235 * that the session once had a controlling terminal. 236 * (for logging and informational purposes) 237 */ 238 } 239 sp->s_leader = NULL; 240 } 241 fixjobc(p, p->p_pgrp, 0); 242 (void)acct_process(p); 243 #ifdef KTRACE 244 /* 245 * release trace file 246 */ 247 ktrderef(p); 248 #endif 249 /* 250 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 251 */ 252 p->p_stat = SDEAD; 253 254 /* 255 * Remove proc from pidhash chain so looking it up won't 256 * work. Move it from allproc to zombproc, but do not yet 257 * wake up the reaper. We will put the proc on the 258 * deadproc list later (using the p_hash member), and 259 * wake up the reaper when we do. 260 */ 261 s = proclist_lock_write(); 262 LIST_REMOVE(p, p_hash); 263 LIST_REMOVE(p, p_list); 264 LIST_INSERT_HEAD(&zombproc, p, p_list); 265 proclist_unlock_write(s); 266 267 /* 268 * Give orphaned children to init(8). 269 */ 270 q = p->p_children.lh_first; 271 if (q) /* only need this if any child is S_ZOMB */ 272 wakeup((caddr_t)initproc); 273 for (; q != 0; q = nq) { 274 nq = q->p_sibling.le_next; 275 proc_reparent(q, initproc); 276 /* 277 * Traced processes are killed 278 * since their existence means someone is screwing up. 279 */ 280 if (q->p_flag & P_TRACED) { 281 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 282 psignal(q, SIGKILL); 283 } 284 } 285 286 /* 287 * Save exit status and final rusage info, adding in child rusage 288 * info and self times. 289 */ 290 p->p_xstat = rv; 291 *p->p_ru = p->p_stats->p_ru; 292 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 293 ruadd(p->p_ru, &p->p_stats->p_cru); 294 295 /* 296 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 297 * flag set, notify init instead (and hope it will handle 298 * this situation). 299 */ 300 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 301 struct proc *pp = p->p_pptr; 302 proc_reparent(p, initproc); 303 /* 304 * If this was the last child of our parent, notify 305 * parent, so in case he was wait(2)ing, he will 306 * continue. 307 */ 308 if (pp->p_children.lh_first == NULL) 309 wakeup((caddr_t)pp); 310 } 311 312 /* 313 * Release the process's signal state. 314 */ 315 sigactsfree(p); 316 317 /* 318 * Clear curproc after we've done all operations 319 * that could block, and before tearing down the rest 320 * of the process state that might be used from clock, etc. 321 * Also, can't clear curproc while we're still runnable, 322 * as we're not on a run queue (we are current, just not 323 * a proper proc any longer!). 324 * 325 * Other substructures are freed from wait(). 326 */ 327 curproc = NULL; 328 limfree(p->p_limit); 329 p->p_limit = NULL; 330 331 /* 332 * Finally, call machine-dependent code to switch to a new 333 * context (possibly the idle context). Once we are no longer 334 * using the dead process's vmspace and stack, exit2() will be 335 * called to schedule those resources to be released by the 336 * reaper thread. 337 * 338 * Note that cpu_exit() will end with a call equivalent to 339 * cpu_switch(), finishing our execution (pun intended). 340 */ 341 cpu_exit(p); 342 } 343 344 /* 345 * We are called from cpu_exit() once it is safe to schedule the 346 * dead process's resources to be freed. 347 * 348 * NOTE: One must be careful with locking in this routine. It's 349 * called from a critical section in machine-dependent code, so 350 * we should refrain from changing any interrupt state. 351 * 352 * We lock the deadproc list (a spin lock), place the proc on that 353 * list (using the p_hash member), and wake up the reaper. 354 */ 355 void 356 exit2(p) 357 struct proc *p; 358 { 359 360 simple_lock(&deadproc_slock); 361 LIST_INSERT_HEAD(&deadproc, p, p_hash); 362 simple_unlock(&deadproc_slock); 363 364 wakeup(&deadproc); 365 } 366 367 /* 368 * Process reaper. This is run by a kernel thread to free the resources 369 * of a dead process. Once the resources are free, the process becomes 370 * a zombie, and the parent is allowed to read the undead's status. 371 */ 372 void 373 reaper() 374 { 375 struct proc *p; 376 377 for (;;) { 378 simple_lock(&deadproc_slock); 379 p = LIST_FIRST(&deadproc); 380 if (p == NULL) { 381 /* No work for us; go to sleep until someone exits. */ 382 simple_unlock(&deadproc_slock); 383 (void) tsleep(&deadproc, PVM, "reaper", 0); 384 continue; 385 } 386 387 /* Remove us from the deadproc list. */ 388 LIST_REMOVE(p, p_hash); 389 simple_unlock(&deadproc_slock); 390 391 /* 392 * Give machine-dependent code a chance to free any 393 * resources it couldn't free while still running on 394 * that process's context. This must be done before 395 * uvm_exit(), in case these resources are in the PCB. 396 */ 397 cpu_wait(p); 398 399 /* 400 * Free the VM resources we're still holding on to. 401 * We must do this from a valid thread because doing 402 * so may block. 403 */ 404 uvm_exit(p); 405 406 /* Process is now a true zombie. */ 407 p->p_stat = SZOMB; 408 409 /* Wake up the parent so it can get exit status. */ 410 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 411 psignal(p->p_pptr, P_EXITSIG(p)); 412 wakeup((caddr_t)p->p_pptr); 413 } 414 } 415 416 int 417 sys_wait4(q, v, retval) 418 struct proc *q; 419 void *v; 420 register_t *retval; 421 { 422 struct sys_wait4_args /* { 423 syscallarg(int) pid; 424 syscallarg(int *) status; 425 syscallarg(int) options; 426 syscallarg(struct rusage *) rusage; 427 } */ *uap = v; 428 int nfound; 429 struct proc *p, *t; 430 int status, error, s; 431 432 if (SCARG(uap, pid) == 0) 433 SCARG(uap, pid) = -q->p_pgid; 434 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG)) 435 return (EINVAL); 436 437 loop: 438 nfound = 0; 439 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 440 if (SCARG(uap, pid) != WAIT_ANY && 441 p->p_pid != SCARG(uap, pid) && 442 p->p_pgid != -SCARG(uap, pid)) 443 continue; 444 /* 445 * Wait for processes with p_exitsig != SIGCHLD processes only 446 * if WALTSIG is set; wait for processes with p_exitsig == 447 * SIGCHLD only if WALTSIG is clear. 448 */ 449 if ((SCARG(uap, options) & WALTSIG) ? 450 (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD)) 451 continue; 452 453 nfound++; 454 if (p->p_stat == SZOMB) { 455 retval[0] = p->p_pid; 456 457 if (SCARG(uap, status)) { 458 status = p->p_xstat; /* convert to int */ 459 error = copyout((caddr_t)&status, 460 (caddr_t)SCARG(uap, status), 461 sizeof(status)); 462 if (error) 463 return (error); 464 } 465 if (SCARG(uap, rusage) && 466 (error = copyout((caddr_t)p->p_ru, 467 (caddr_t)SCARG(uap, rusage), 468 sizeof(struct rusage)))) 469 return (error); 470 /* 471 * If we got the child via ptrace(2) or procfs, and 472 * the parent is different (meaning the process was 473 * attached, rather than run as a child), then we need 474 * to give it back to the old parent, and send the 475 * parent the exit signal. The rest of the cleanup 476 * will be done when the old parent waits on the child. 477 */ 478 if ((p->p_flag & P_TRACED) && 479 p->p_oppid != p->p_pptr->p_pid) { 480 t = pfind(p->p_oppid); 481 proc_reparent(p, t ? t : initproc); 482 p->p_oppid = 0; 483 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 484 if (p->p_exitsig != 0) 485 psignal(p->p_pptr, P_EXITSIG(p)); 486 wakeup((caddr_t)p->p_pptr); 487 return (0); 488 } 489 scheduler_wait_hook(q, p); 490 p->p_xstat = 0; 491 ruadd(&q->p_stats->p_cru, p->p_ru); 492 pool_put(&rusage_pool, p->p_ru); 493 494 /* 495 * Finally finished with old proc entry. 496 * Unlink it from its process group and free it. 497 */ 498 leavepgrp(p); 499 500 s = proclist_lock_write(); 501 LIST_REMOVE(p, p_list); /* off zombproc */ 502 proclist_unlock_write(s); 503 504 LIST_REMOVE(p, p_sibling); 505 506 /* 507 * Decrement the count of procs running with this uid. 508 */ 509 (void)chgproccnt(p->p_cred->p_ruid, -1); 510 511 /* 512 * Free up credentials. 513 */ 514 if (--p->p_cred->p_refcnt == 0) { 515 crfree(p->p_cred->pc_ucred); 516 pool_put(&pcred_pool, p->p_cred); 517 } 518 519 /* 520 * Release reference to text vnode 521 */ 522 if (p->p_textvp) 523 vrele(p->p_textvp); 524 525 pool_put(&proc_pool, p); 526 nprocs--; 527 return (0); 528 } 529 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 530 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 531 p->p_flag |= P_WAITED; 532 retval[0] = p->p_pid; 533 534 if (SCARG(uap, status)) { 535 status = W_STOPCODE(p->p_xstat); 536 error = copyout((caddr_t)&status, 537 (caddr_t)SCARG(uap, status), 538 sizeof(status)); 539 } else 540 error = 0; 541 return (error); 542 } 543 } 544 if (nfound == 0) 545 return (ECHILD); 546 if (SCARG(uap, options) & WNOHANG) { 547 retval[0] = 0; 548 return (0); 549 } 550 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 551 return (error); 552 goto loop; 553 } 554 555 /* 556 * make process 'parent' the new parent of process 'child'. 557 */ 558 void 559 proc_reparent(child, parent) 560 struct proc *child; 561 struct proc *parent; 562 { 563 564 if (child->p_pptr == parent) 565 return; 566 567 if (parent == initproc) 568 child->p_exitsig = SIGCHLD; 569 570 LIST_REMOVE(child, p_sibling); 571 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 572 child->p_pptr = parent; 573 } 574