1 /* $NetBSD: kern_exit.c,v 1.61 1998/11/11 22:37:13 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 1998 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_uvm.h" 82 #include "opt_sysv.h" 83 84 #include <sys/param.h> 85 #include <sys/systm.h> 86 #include <sys/map.h> 87 #include <sys/ioctl.h> 88 #include <sys/proc.h> 89 #include <sys/tty.h> 90 #include <sys/time.h> 91 #include <sys/resource.h> 92 #include <sys/kernel.h> 93 #include <sys/ktrace.h> 94 #include <sys/proc.h> 95 #include <sys/buf.h> 96 #include <sys/wait.h> 97 #include <sys/file.h> 98 #include <sys/vnode.h> 99 #include <sys/syslog.h> 100 #include <sys/malloc.h> 101 #include <sys/pool.h> 102 #include <sys/resourcevar.h> 103 #include <sys/ptrace.h> 104 #include <sys/acct.h> 105 #include <sys/filedesc.h> 106 #include <sys/signalvar.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 #if defined(UVM) 123 #include <uvm/uvm_extern.h> 124 #endif 125 126 /* 127 * exit -- 128 * Death of process. 129 */ 130 int 131 sys_exit(p, v, retval) 132 struct proc *p; 133 void *v; 134 register_t *retval; 135 { 136 struct sys_exit_args /* { 137 syscallarg(int) rval; 138 } */ *uap = v; 139 140 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 141 /* NOTREACHED */ 142 return (0); 143 } 144 145 /* 146 * Exit: deallocate address space and other resources, change proc state 147 * to zombie, and unlink proc from allproc and parent's lists. Save exit 148 * status and rusage for wait(). Check for child processes and orphan them. 149 */ 150 void 151 exit1(p, rv) 152 register struct proc *p; 153 int rv; 154 { 155 register struct proc *q, *nq; 156 register struct vmspace *vm; 157 158 if (p->p_pid == 1) 159 panic("init died (signal %d, exit %d)", 160 WTERMSIG(rv), WEXITSTATUS(rv)); 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 untimeout(realitexpire, (caddr_t)p); 180 181 /* 182 * Close open files and release open-file table. 183 * This may block! 184 */ 185 fdfree(p); 186 187 /* The next three chunks should probably be moved to vmspace_exit. */ 188 vm = p->p_vmspace; 189 #ifdef SYSVSHM 190 if (vm->vm_shm && vm->vm_refcnt == 1) 191 shmexit(vm); 192 #endif 193 #ifdef SYSVSEM 194 semexit(p); 195 #endif 196 /* 197 * Release user portion of address space. 198 * This releases references to vnodes, 199 * which could cause I/O if the file has been unlinked. 200 * Need to do this early enough that we can still sleep. 201 * Can't free the entire vmspace as the kernel stack 202 * may be mapped within that space also. 203 */ 204 #if defined(UVM) 205 if (vm->vm_refcnt == 1) 206 (void) uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 207 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 208 #else 209 if (vm->vm_refcnt == 1) 210 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS, 211 VM_MAXUSER_ADDRESS); 212 #endif 213 214 if (SESS_LEADER(p)) { 215 register struct session *sp = p->p_session; 216 217 if (sp->s_ttyvp) { 218 /* 219 * Controlling process. 220 * Signal foreground pgrp, 221 * drain controlling terminal 222 * and revoke access to controlling terminal. 223 */ 224 if (sp->s_ttyp->t_session == sp) { 225 if (sp->s_ttyp->t_pgrp) 226 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 227 (void) ttywait(sp->s_ttyp); 228 /* 229 * The tty could have been revoked 230 * if we blocked. 231 */ 232 if (sp->s_ttyvp) 233 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 234 } 235 if (sp->s_ttyvp) 236 vrele(sp->s_ttyvp); 237 sp->s_ttyvp = NULL; 238 /* 239 * s_ttyp is not zero'd; we use this to indicate 240 * that the session once had a controlling terminal. 241 * (for logging and informational purposes) 242 */ 243 } 244 sp->s_leader = NULL; 245 } 246 fixjobc(p, p->p_pgrp, 0); 247 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 248 (void)acct_process(p); 249 #ifdef KTRACE 250 /* 251 * release trace file 252 */ 253 ktrderef(p); 254 #endif 255 /* 256 * Remove proc from allproc queue and pidhash chain. 257 * Unlink from parent's child list. 258 */ 259 LIST_REMOVE(p, p_list); 260 p->p_stat = SZOMB; 261 262 /* 263 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 264 */ 265 266 LIST_REMOVE(p, p_hash); 267 268 q = p->p_children.lh_first; 269 if (q) /* only need this if any child is S_ZOMB */ 270 wakeup((caddr_t)initproc); 271 for (; q != 0; q = nq) { 272 nq = q->p_sibling.le_next; 273 proc_reparent(q, initproc); 274 /* 275 * Traced processes are killed 276 * since their existence means someone is screwing up. 277 */ 278 if (q->p_flag & P_TRACED) { 279 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 280 psignal(q, SIGKILL); 281 } 282 } 283 284 /* 285 * Save exit status and final rusage info, adding in child rusage 286 * info and self times. 287 */ 288 p->p_xstat = rv; 289 *p->p_ru = p->p_stats->p_ru; 290 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 291 ruadd(p->p_ru, &p->p_stats->p_cru); 292 293 /* 294 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 295 * flag set, notify init instead (and hope it will handle 296 * this situation). 297 */ 298 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 299 struct proc *pp = p->p_pptr; 300 proc_reparent(p, initproc); 301 /* 302 * If this was the last child of our parent, notify 303 * parent, so in case he was wait(2)ing, he will 304 * continue. 305 */ 306 if (pp->p_children.lh_first == NULL) 307 wakeup((caddr_t)pp); 308 } 309 310 /* 311 * Clear curproc after we've done all operations 312 * that could block, and before tearing down the rest 313 * of the process state that might be used from clock, etc. 314 * Also, can't clear curproc while we're still runnable, 315 * as we're not on a run queue (we are current, just not 316 * a proper proc any longer!). 317 * 318 * Other substructures are freed from wait(). 319 */ 320 curproc = NULL; 321 if (--p->p_limit->p_refcnt == 0) 322 pool_put(&plimit_pool, p->p_limit); 323 324 /* 325 * Finally, call machine-dependent code to switch to a new 326 * context (possibly the idle context). Once we are no longer 327 * using the dead process's vmspace and stack, exit2() will be 328 * called to schedule those resources to be released by the 329 * reaper thread. 330 * 331 * Note that cpu_exit() will end with a call equivalent to 332 * cpu_switch(), finishing our execution (pun intended). 333 */ 334 cpu_exit(p); 335 } 336 337 /* 338 * We are called from cpu_exit() once it is safe to schedule the 339 * dead process's resources to be freed. 340 */ 341 void 342 exit2(p) 343 struct proc *p; 344 { 345 346 LIST_INSERT_HEAD(&deadproc, p, p_list); 347 wakeup(&deadproc); 348 } 349 350 /* 351 * Process reaper. This is run by a kernel thread to free the resources 352 * of a dead process. Once the resources are free, the process becomes 353 * a zombie, and the parent is allowed to read the undead's status. 354 */ 355 void 356 reaper() 357 { 358 struct proc *p; 359 360 for (;;) { 361 p = LIST_FIRST(&deadproc); 362 if (p == NULL) { 363 /* No work for us; go to sleep until someone exits. */ 364 (void) tsleep(&deadproc, PVM, "reaper", 0); 365 continue; 366 } 367 368 /* Remove us from the deadproc list. */ 369 LIST_REMOVE(p, p_list); 370 371 /* 372 * Free the VM resources we're still holding on to. 373 * We must do this from a valid thread because doing 374 * so may block. 375 */ 376 #if defined(UVM) 377 uvm_exit(p); 378 #else 379 vm_exit(p); 380 #endif 381 382 /* Process is now a true zombie. */ 383 LIST_INSERT_HEAD(&zombproc, p, p_list); 384 385 /* Wake up the parent so it can get exit satus. */ 386 if ((p->p_flag & P_FSTRACE) == 0) 387 psignal(p->p_pptr, SIGCHLD); 388 wakeup((caddr_t)p->p_pptr); 389 } 390 } 391 392 int 393 sys_wait4(q, v, retval) 394 register struct proc *q; 395 void *v; 396 register_t *retval; 397 { 398 register struct sys_wait4_args /* { 399 syscallarg(int) pid; 400 syscallarg(int *) status; 401 syscallarg(int) options; 402 syscallarg(struct rusage *) rusage; 403 } */ *uap = v; 404 register int nfound; 405 register struct proc *p, *t; 406 int status, error; 407 408 if (SCARG(uap, pid) == 0) 409 SCARG(uap, pid) = -q->p_pgid; 410 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG)) 411 return (EINVAL); 412 413 loop: 414 nfound = 0; 415 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 416 if (SCARG(uap, pid) != WAIT_ANY && 417 p->p_pid != SCARG(uap, pid) && 418 p->p_pgid != -SCARG(uap, pid)) 419 continue; 420 nfound++; 421 if (p->p_stat == SZOMB) { 422 retval[0] = p->p_pid; 423 424 if (SCARG(uap, status)) { 425 status = p->p_xstat; /* convert to int */ 426 error = copyout((caddr_t)&status, 427 (caddr_t)SCARG(uap, status), 428 sizeof(status)); 429 if (error) 430 return (error); 431 } 432 if (SCARG(uap, rusage) && 433 (error = copyout((caddr_t)p->p_ru, 434 (caddr_t)SCARG(uap, rusage), 435 sizeof(struct rusage)))) 436 return (error); 437 /* 438 * If we got the child via ptrace(2) or procfs, and 439 * the parent is different (meaning the process was 440 * attached, rather than run as a child), then we need 441 * to give it back to the old parent, and send the 442 * parent a SIGCHLD. The rest of the cleanup will be 443 * done when the old parent waits on the child. 444 */ 445 if ((p->p_flag & P_TRACED) && 446 p->p_oppid != p->p_pptr->p_pid) { 447 t = pfind(p->p_oppid); 448 proc_reparent(p, t ? t : initproc); 449 p->p_oppid = 0; 450 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 451 psignal(p->p_pptr, SIGCHLD); 452 wakeup((caddr_t)p->p_pptr); 453 return (0); 454 } 455 p->p_xstat = 0; 456 ruadd(&q->p_stats->p_cru, p->p_ru); 457 pool_put(&rusage_pool, p->p_ru); 458 459 /* 460 * Finally finished with old proc entry. 461 * Unlink it from its process group and free it. 462 */ 463 leavepgrp(p); 464 465 LIST_REMOVE(p, p_list); /* off zombproc */ 466 467 LIST_REMOVE(p, p_sibling); 468 469 /* 470 * Decrement the count of procs running with this uid. 471 */ 472 (void)chgproccnt(p->p_cred->p_ruid, -1); 473 474 /* 475 * Free up credentials. 476 */ 477 if (--p->p_cred->p_refcnt == 0) { 478 crfree(p->p_cred->pc_ucred); 479 pool_put(&pcred_pool, p->p_cred); 480 } 481 482 /* 483 * Release reference to text vnode 484 */ 485 if (p->p_textvp) 486 vrele(p->p_textvp); 487 488 /* 489 * Give machine-dependent layer a chance 490 * to free anything that cpu_exit couldn't 491 * release while still running in process context. 492 */ 493 cpu_wait(p); 494 pool_put(&proc_pool, p); 495 nprocs--; 496 return (0); 497 } 498 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 499 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 500 p->p_flag |= P_WAITED; 501 retval[0] = p->p_pid; 502 503 if (SCARG(uap, status)) { 504 status = W_STOPCODE(p->p_xstat); 505 error = copyout((caddr_t)&status, 506 (caddr_t)SCARG(uap, status), 507 sizeof(status)); 508 } else 509 error = 0; 510 return (error); 511 } 512 } 513 if (nfound == 0) 514 return (ECHILD); 515 if (SCARG(uap, options) & WNOHANG) { 516 retval[0] = 0; 517 return (0); 518 } 519 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 520 return (error); 521 goto loop; 522 } 523 524 /* 525 * make process 'parent' the new parent of process 'child'. 526 */ 527 void 528 proc_reparent(child, parent) 529 register struct proc *child; 530 register struct proc *parent; 531 { 532 533 if (child->p_pptr == parent) 534 return; 535 536 LIST_REMOVE(child, p_sibling); 537 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 538 child->p_pptr = parent; 539 } 540