1 /* $NetBSD: kern_exit.c,v 1.81 2000/06/27 17:41:18 mrg 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 <uvm/uvm_extern.h> 120 121 /* 122 * exit -- 123 * Death of process. 124 */ 125 int 126 sys_exit(p, v, retval) 127 struct proc *p; 128 void *v; 129 register_t *retval; 130 { 131 struct sys_exit_args /* { 132 syscallarg(int) rval; 133 } */ *uap = v; 134 135 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 136 /* NOTREACHED */ 137 return (0); 138 } 139 140 /* 141 * Exit: deallocate address space and other resources, change proc state 142 * to zombie, and unlink proc from allproc and parent's lists. Save exit 143 * status and rusage for wait(). Check for child processes and orphan them. 144 */ 145 void 146 exit1(p, rv) 147 struct proc *p; 148 int rv; 149 { 150 struct proc *q, *nq; 151 struct vmspace *vm; 152 int s; 153 154 if (__predict_false(p == initproc)) 155 panic("init died (signal %d, exit %d)", 156 WTERMSIG(rv), WEXITSTATUS(rv)); 157 158 #ifdef PGINPROF 159 vmsizmon(); 160 #endif 161 if (p->p_flag & P_PROFIL) 162 stopprofclock(p); 163 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 164 /* 165 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 166 * wake up the parent early to avoid deadlock. 167 */ 168 p->p_flag |= P_WEXIT; 169 if (p->p_flag & P_PPWAIT) { 170 p->p_flag &= ~P_PPWAIT; 171 wakeup((caddr_t)p->p_pptr); 172 } 173 sigfillset(&p->p_sigignore); 174 sigemptyset(&p->p_siglist); 175 p->p_sigcheck = 0; 176 callout_stop(&p->p_realit_ch); 177 178 /* 179 * Close open files and release open-file table. 180 * This may block! 181 */ 182 fdfree(p); 183 cwdfree(p); 184 185 /* The next three chunks should probably be moved to vmspace_exit. */ 186 vm = p->p_vmspace; 187 #ifdef SYSVSHM 188 if (vm->vm_shm && vm->vm_refcnt == 1) 189 shmexit(vm); 190 #endif 191 #ifdef SYSVSEM 192 semexit(p); 193 #endif 194 /* 195 * Release user portion of address space. 196 * This releases references to vnodes, 197 * which could cause I/O if the file has been unlinked. 198 * Need to do this early enough that we can still sleep. 199 * Can't free the entire vmspace as the kernel stack 200 * may be mapped within that space also. 201 */ 202 if (vm->vm_refcnt == 1) 203 (void) uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 204 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 205 206 if (SESS_LEADER(p)) { 207 struct session *sp = p->p_session; 208 209 if (sp->s_ttyvp) { 210 /* 211 * Controlling process. 212 * Signal foreground pgrp, 213 * drain controlling terminal 214 * and revoke access to controlling terminal. 215 */ 216 if (sp->s_ttyp->t_session == sp) { 217 if (sp->s_ttyp->t_pgrp) 218 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 219 (void) ttywait(sp->s_ttyp); 220 /* 221 * The tty could have been revoked 222 * if we blocked. 223 */ 224 if (sp->s_ttyvp) 225 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 226 } 227 if (sp->s_ttyvp) 228 vrele(sp->s_ttyvp); 229 sp->s_ttyvp = NULL; 230 /* 231 * s_ttyp is not zero'd; we use this to indicate 232 * that the session once had a controlling terminal. 233 * (for logging and informational purposes) 234 */ 235 } 236 sp->s_leader = NULL; 237 } 238 fixjobc(p, p->p_pgrp, 0); 239 (void)acct_process(p); 240 #ifdef KTRACE 241 /* 242 * release trace file 243 */ 244 ktrderef(p); 245 #endif 246 /* 247 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 248 */ 249 p->p_stat = SDEAD; 250 251 /* 252 * Remove proc from pidhash chain so looking it up won't 253 * work. Move it from allproc to zombproc, but do not yet 254 * wake up the reaper. We will put the proc on the 255 * deadproc list later (using the p_hash member), and 256 * wake up the reaper when we do. 257 */ 258 s = proclist_lock_write(); 259 LIST_REMOVE(p, p_hash); 260 LIST_REMOVE(p, p_list); 261 LIST_INSERT_HEAD(&zombproc, p, p_list); 262 proclist_unlock_write(s); 263 264 /* 265 * Give orphaned children to init(8). 266 */ 267 q = p->p_children.lh_first; 268 if (q) /* only need this if any child is S_ZOMB */ 269 wakeup((caddr_t)initproc); 270 for (; q != 0; q = nq) { 271 nq = q->p_sibling.le_next; 272 proc_reparent(q, initproc); 273 /* 274 * Traced processes are killed 275 * since their existence means someone is screwing up. 276 */ 277 if (q->p_flag & P_TRACED) { 278 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 279 psignal(q, SIGKILL); 280 } 281 } 282 283 /* 284 * Save exit status and final rusage info, adding in child rusage 285 * info and self times. 286 */ 287 p->p_xstat = rv; 288 *p->p_ru = p->p_stats->p_ru; 289 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 290 ruadd(p->p_ru, &p->p_stats->p_cru); 291 292 /* 293 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 294 * flag set, notify init instead (and hope it will handle 295 * this situation). 296 */ 297 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 298 struct proc *pp = p->p_pptr; 299 proc_reparent(p, initproc); 300 /* 301 * If this was the last child of our parent, notify 302 * parent, so in case he was wait(2)ing, he will 303 * continue. 304 */ 305 if (pp->p_children.lh_first == NULL) 306 wakeup((caddr_t)pp); 307 } 308 309 /* 310 * Release the process's signal state. 311 */ 312 sigactsfree(p); 313 314 /* 315 * Clear curproc after we've done all operations 316 * that could block, and before tearing down the rest 317 * of the process state that might be used from clock, etc. 318 * Also, can't clear curproc while we're still runnable, 319 * as we're not on a run queue (we are current, just not 320 * a proper proc any longer!). 321 * 322 * Other substructures are freed from wait(). 323 */ 324 curproc = NULL; 325 limfree(p->p_limit); 326 p->p_limit = NULL; 327 328 /* 329 * Finally, call machine-dependent code to switch to a new 330 * context (possibly the idle context). Once we are no longer 331 * using the dead process's vmspace and stack, exit2() will be 332 * called to schedule those resources to be released by the 333 * reaper thread. 334 * 335 * Note that cpu_exit() will end with a call equivalent to 336 * cpu_switch(), finishing our execution (pun intended). 337 */ 338 cpu_exit(p); 339 } 340 341 /* 342 * We are called from cpu_exit() once it is safe to schedule the 343 * dead process's resources to be freed. 344 * 345 * NOTE: One must be careful with locking in this routine. It's 346 * called from a critical section in machine-dependent code, so 347 * we should refrain from changing any interrupt state. 348 * 349 * We lock the deadproc list (a spin lock), place the proc on that 350 * list (using the p_hash member), and wake up the reaper. 351 */ 352 void 353 exit2(p) 354 struct proc *p; 355 { 356 357 simple_lock(&deadproc_slock); 358 LIST_INSERT_HEAD(&deadproc, p, p_hash); 359 simple_unlock(&deadproc_slock); 360 361 wakeup(&deadproc); 362 } 363 364 /* 365 * Process reaper. This is run by a kernel thread to free the resources 366 * of a dead process. Once the resources are free, the process becomes 367 * a zombie, and the parent is allowed to read the undead's status. 368 */ 369 void 370 reaper() 371 { 372 struct proc *p; 373 374 for (;;) { 375 simple_lock(&deadproc_slock); 376 p = LIST_FIRST(&deadproc); 377 if (p == NULL) { 378 /* No work for us; go to sleep until someone exits. */ 379 simple_unlock(&deadproc_slock); 380 (void) tsleep(&deadproc, PVM, "reaper", 0); 381 continue; 382 } 383 384 /* Remove us from the deadproc list. */ 385 LIST_REMOVE(p, p_hash); 386 simple_unlock(&deadproc_slock); 387 388 /* 389 * Give machine-dependent code a chance to free any 390 * resources it couldn't free while still running on 391 * that process's context. This must be done before 392 * uvm_exit(), in case these resources are in the PCB. 393 */ 394 cpu_wait(p); 395 396 /* 397 * Free the VM resources we're still holding on to. 398 * We must do this from a valid thread because doing 399 * so may block. 400 */ 401 uvm_exit(p); 402 403 /* Process is now a true zombie. */ 404 p->p_stat = SZOMB; 405 406 /* Wake up the parent so it can get exit status. */ 407 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 408 psignal(p->p_pptr, P_EXITSIG(p)); 409 wakeup((caddr_t)p->p_pptr); 410 } 411 } 412 413 int 414 sys_wait4(q, v, retval) 415 struct proc *q; 416 void *v; 417 register_t *retval; 418 { 419 struct sys_wait4_args /* { 420 syscallarg(int) pid; 421 syscallarg(int *) status; 422 syscallarg(int) options; 423 syscallarg(struct rusage *) rusage; 424 } */ *uap = v; 425 int nfound; 426 struct proc *p, *t; 427 int status, error, s; 428 429 if (SCARG(uap, pid) == 0) 430 SCARG(uap, pid) = -q->p_pgid; 431 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG)) 432 return (EINVAL); 433 434 loop: 435 nfound = 0; 436 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 437 if (SCARG(uap, pid) != WAIT_ANY && 438 p->p_pid != SCARG(uap, pid) && 439 p->p_pgid != -SCARG(uap, pid)) 440 continue; 441 /* 442 * Wait for processes with p_exitsig != SIGCHLD processes only 443 * if WALTSIG is set; wait for processes with p_exitsig == 444 * SIGCHLD only if WALTSIG is clear. 445 */ 446 if ((SCARG(uap, options) & WALTSIG) ? 447 (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD)) 448 continue; 449 450 nfound++; 451 if (p->p_stat == SZOMB) { 452 retval[0] = p->p_pid; 453 454 if (SCARG(uap, status)) { 455 status = p->p_xstat; /* convert to int */ 456 error = copyout((caddr_t)&status, 457 (caddr_t)SCARG(uap, status), 458 sizeof(status)); 459 if (error) 460 return (error); 461 } 462 if (SCARG(uap, rusage) && 463 (error = copyout((caddr_t)p->p_ru, 464 (caddr_t)SCARG(uap, rusage), 465 sizeof(struct rusage)))) 466 return (error); 467 /* 468 * If we got the child via ptrace(2) or procfs, and 469 * the parent is different (meaning the process was 470 * attached, rather than run as a child), then we need 471 * to give it back to the old parent, and send the 472 * parent the exit signal. The rest of the cleanup 473 * will be done when the old parent waits on the child. 474 */ 475 if ((p->p_flag & P_TRACED) && 476 p->p_oppid != p->p_pptr->p_pid) { 477 t = pfind(p->p_oppid); 478 proc_reparent(p, t ? t : initproc); 479 p->p_oppid = 0; 480 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 481 if (p->p_exitsig != 0) 482 psignal(p->p_pptr, P_EXITSIG(p)); 483 wakeup((caddr_t)p->p_pptr); 484 return (0); 485 } 486 scheduler_wait_hook(q, p); 487 p->p_xstat = 0; 488 ruadd(&q->p_stats->p_cru, p->p_ru); 489 pool_put(&rusage_pool, p->p_ru); 490 491 /* 492 * Finally finished with old proc entry. 493 * Unlink it from its process group and free it. 494 */ 495 leavepgrp(p); 496 497 s = proclist_lock_write(); 498 LIST_REMOVE(p, p_list); /* off zombproc */ 499 proclist_unlock_write(s); 500 501 LIST_REMOVE(p, p_sibling); 502 503 /* 504 * Decrement the count of procs running with this uid. 505 */ 506 (void)chgproccnt(p->p_cred->p_ruid, -1); 507 508 /* 509 * Free up credentials. 510 */ 511 if (--p->p_cred->p_refcnt == 0) { 512 crfree(p->p_cred->pc_ucred); 513 pool_put(&pcred_pool, p->p_cred); 514 } 515 516 /* 517 * Release reference to text vnode 518 */ 519 if (p->p_textvp) 520 vrele(p->p_textvp); 521 522 pool_put(&proc_pool, 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 || SCARG(uap, options) & WUNTRACED)) { 528 p->p_flag |= P_WAITED; 529 retval[0] = p->p_pid; 530 531 if (SCARG(uap, status)) { 532 status = W_STOPCODE(p->p_xstat); 533 error = copyout((caddr_t)&status, 534 (caddr_t)SCARG(uap, status), 535 sizeof(status)); 536 } else 537 error = 0; 538 return (error); 539 } 540 } 541 if (nfound == 0) 542 return (ECHILD); 543 if (SCARG(uap, options) & WNOHANG) { 544 retval[0] = 0; 545 return (0); 546 } 547 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 548 return (error); 549 goto loop; 550 } 551 552 /* 553 * make process 'parent' the new parent of process 'child'. 554 */ 555 void 556 proc_reparent(child, parent) 557 struct proc *child; 558 struct proc *parent; 559 { 560 561 if (child->p_pptr == parent) 562 return; 563 564 if (parent == initproc) 565 child->p_exitsig = SIGCHLD; 566 567 LIST_REMOVE(child, p_sibling); 568 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 569 child->p_pptr = parent; 570 } 571