kern_exit.c revision 1.56
1 /* $NetBSD: kern_exit.c,v 1.56 1998/09/08 23:57:58 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 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 #ifdef SYSVSHM 107 #include <sys/shm.h> 108 #endif 109 #ifdef SYSVSEM 110 #include <sys/sem.h> 111 #endif 112 113 #include <sys/mount.h> 114 #include <sys/syscallargs.h> 115 116 #include <machine/cpu.h> 117 118 #include <vm/vm.h> 119 #include <vm/vm_kern.h> 120 121 #if defined(UVM) 122 #include <uvm/uvm_extern.h> 123 #endif 124 125 /* 126 * exit -- 127 * Death of process. 128 */ 129 int 130 sys_exit(p, v, retval) 131 struct proc *p; 132 void *v; 133 register_t *retval; 134 { 135 struct sys_exit_args /* { 136 syscallarg(int) rval; 137 } */ *uap = v; 138 139 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 140 /* NOTREACHED */ 141 return (0); 142 } 143 144 /* 145 * Exit: deallocate address space and other resources, change proc state 146 * to zombie, and unlink proc from allproc and parent's lists. Save exit 147 * status and rusage for wait(). Check for child processes and orphan them. 148 */ 149 void 150 exit1(p, rv) 151 register struct proc *p; 152 int rv; 153 { 154 register struct proc *q, *nq; 155 register struct vmspace *vm; 156 157 if (p->p_pid == 1) 158 panic("init died (signal %d, exit %d)", 159 WTERMSIG(rv), WEXITSTATUS(rv)); 160 #ifdef PGINPROF 161 vmsizmon(); 162 #endif 163 if (p->p_flag & P_PROFIL) 164 stopprofclock(p); 165 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 166 /* 167 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 168 * wake up the parent early to avoid deadlock. 169 */ 170 p->p_flag |= P_WEXIT; 171 if (p->p_flag & P_PPWAIT) { 172 p->p_flag &= ~P_PPWAIT; 173 wakeup((caddr_t)p->p_pptr); 174 } 175 p->p_sigignore = ~0; 176 p->p_siglist = 0; 177 untimeout(realitexpire, (caddr_t)p); 178 179 /* 180 * Close open files and release open-file table. 181 * This may block! 182 */ 183 fdfree(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 defined(UVM) 203 if (vm->vm_refcnt == 1) 204 (void) uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 205 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 206 #else 207 if (vm->vm_refcnt == 1) 208 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS, 209 VM_MAXUSER_ADDRESS); 210 #endif 211 212 if (SESS_LEADER(p)) { 213 register struct session *sp = p->p_session; 214 215 if (sp->s_ttyvp) { 216 /* 217 * Controlling process. 218 * Signal foreground pgrp, 219 * drain controlling terminal 220 * and revoke access to controlling terminal. 221 */ 222 if (sp->s_ttyp->t_session == sp) { 223 if (sp->s_ttyp->t_pgrp) 224 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 225 (void) ttywait(sp->s_ttyp); 226 /* 227 * The tty could have been revoked 228 * if we blocked. 229 */ 230 if (sp->s_ttyvp) 231 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 232 } 233 if (sp->s_ttyvp) 234 vrele(sp->s_ttyvp); 235 sp->s_ttyvp = NULL; 236 /* 237 * s_ttyp is not zero'd; we use this to indicate 238 * that the session once had a controlling terminal. 239 * (for logging and informational purposes) 240 */ 241 } 242 sp->s_leader = NULL; 243 } 244 fixjobc(p, p->p_pgrp, 0); 245 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 246 (void)acct_process(p); 247 #ifdef KTRACE 248 /* 249 * release trace file 250 */ 251 ktrderef(p); 252 #endif 253 /* 254 * Remove proc from allproc queue and pidhash chain. 255 * Unlink from parent's child list. 256 */ 257 LIST_REMOVE(p, p_list); 258 p->p_stat = SZOMB; 259 260 /* 261 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 262 */ 263 264 LIST_REMOVE(p, p_hash); 265 266 q = p->p_children.lh_first; 267 if (q) /* only need this if any child is S_ZOMB */ 268 wakeup((caddr_t)initproc); 269 for (; q != 0; q = nq) { 270 nq = q->p_sibling.le_next; 271 proc_reparent(q, initproc); 272 /* 273 * Traced processes are killed 274 * since their existence means someone is screwing up. 275 */ 276 if (q->p_flag & P_TRACED) { 277 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 278 psignal(q, SIGKILL); 279 } 280 } 281 282 /* 283 * Save exit status and final rusage info, adding in child rusage 284 * info and self times. 285 */ 286 p->p_xstat = rv; 287 *p->p_ru = p->p_stats->p_ru; 288 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 289 ruadd(p->p_ru, &p->p_stats->p_cru); 290 291 /* 292 * Clear curproc after we've done all operations 293 * that could block, and before tearing down the rest 294 * of the process state that might be used from clock, etc. 295 * Also, can't clear curproc while we're still runnable, 296 * as we're not on a run queue (we are current, just not 297 * a proper proc any longer!). 298 * 299 * Other substructures are freed from wait(). 300 */ 301 curproc = NULL; 302 if (--p->p_limit->p_refcnt == 0) 303 pool_put(&plimit_pool, p->p_limit); 304 305 /* 306 * Finally, call machine-dependent code to switch to a new 307 * context (possibly the idle context). Once we are no longer 308 * using the dead process's vmspace and stack, exit2() will be 309 * called to schedule those resources to be released by the 310 * reaper thread. 311 * 312 * Note that cpu_exit() will end with a call equivalent to 313 * cpu_switch(), finishing our execution (pun intended). 314 */ 315 cpu_exit(p); 316 } 317 318 /* 319 * We are called from cpu_exit() once it is safe to schedule the 320 * dead process's resources to be freed. 321 */ 322 void 323 exit2(p) 324 struct proc *p; 325 { 326 327 LIST_INSERT_HEAD(&deadproc, p, p_list); 328 wakeup(&deadproc); 329 } 330 331 /* 332 * Process reaper. This is run by a kernel thread to free the resources 333 * of a dead process. Once the resources are free, the process becomes 334 * a zombie, and the parent is allowed to read the undead's status. 335 */ 336 void 337 reaper() 338 { 339 struct proc *p; 340 341 for (;;) { 342 p = LIST_FIRST(&deadproc); 343 if (p == NULL) { 344 /* No work for us; go to sleep until someone exits. */ 345 (void) tsleep(&deadproc, PVM, "reaper", 0); 346 continue; 347 } 348 349 /* Remove us from the deadproc list. */ 350 LIST_REMOVE(p, p_list); 351 352 /* 353 * Free the VM resources we're still holding on to. 354 * We must do this from a valid thread because doing 355 * so may block. 356 */ 357 #if defined(UVM) 358 uvm_exit(p); 359 #else 360 vm_exit(p); 361 #endif 362 363 /* Process is now a true zombie. */ 364 LIST_INSERT_HEAD(&zombproc, p, p_list); 365 366 /* Wake up the parent so it can get exit satus. */ 367 if ((p->p_flag & P_FSTRACE) == 0) 368 psignal(p->p_pptr, SIGCHLD); 369 wakeup((caddr_t)p->p_pptr); 370 } 371 } 372 373 int 374 sys_wait4(q, v, retval) 375 register struct proc *q; 376 void *v; 377 register_t *retval; 378 { 379 register struct sys_wait4_args /* { 380 syscallarg(int) pid; 381 syscallarg(int *) status; 382 syscallarg(int) options; 383 syscallarg(struct rusage *) rusage; 384 } */ *uap = v; 385 register int nfound; 386 register struct proc *p, *t; 387 int status, error; 388 389 if (SCARG(uap, pid) == 0) 390 SCARG(uap, pid) = -q->p_pgid; 391 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG)) 392 return (EINVAL); 393 394 loop: 395 nfound = 0; 396 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 397 if (SCARG(uap, pid) != WAIT_ANY && 398 p->p_pid != SCARG(uap, pid) && 399 p->p_pgid != -SCARG(uap, pid)) 400 continue; 401 nfound++; 402 if (p->p_stat == SZOMB) { 403 retval[0] = p->p_pid; 404 405 if (SCARG(uap, status)) { 406 status = p->p_xstat; /* convert to int */ 407 error = copyout((caddr_t)&status, 408 (caddr_t)SCARG(uap, status), 409 sizeof(status)); 410 if (error) 411 return (error); 412 } 413 if (SCARG(uap, rusage) && 414 (error = copyout((caddr_t)p->p_ru, 415 (caddr_t)SCARG(uap, rusage), 416 sizeof(struct rusage)))) 417 return (error); 418 /* 419 * If we got the child via ptrace(2) or procfs, and 420 * the parent is different (meaning the process was 421 * attached, rather than run as a child), then we need 422 * to give it back to the old parent, and send the 423 * parent a SIGCHLD. The rest of the cleanup will be 424 * done when the old parent waits on the child. 425 */ 426 if ((p->p_flag & P_TRACED) && 427 p->p_oppid != p->p_pptr->p_pid) { 428 t = pfind(p->p_oppid); 429 proc_reparent(p, t ? t : initproc); 430 p->p_oppid = 0; 431 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 432 psignal(p->p_pptr, SIGCHLD); 433 wakeup((caddr_t)p->p_pptr); 434 return (0); 435 } 436 p->p_xstat = 0; 437 ruadd(&q->p_stats->p_cru, p->p_ru); 438 pool_put(&rusage_pool, p->p_ru); 439 440 /* 441 * Finally finished with old proc entry. 442 * Unlink it from its process group and free it. 443 */ 444 leavepgrp(p); 445 446 LIST_REMOVE(p, p_list); /* off zombproc */ 447 448 LIST_REMOVE(p, p_sibling); 449 450 /* 451 * Decrement the count of procs running with this uid. 452 */ 453 (void)chgproccnt(p->p_cred->p_ruid, -1); 454 455 /* 456 * Free up credentials. 457 */ 458 if (--p->p_cred->p_refcnt == 0) { 459 crfree(p->p_cred->pc_ucred); 460 pool_put(&pcred_pool, p->p_cred); 461 } 462 463 /* 464 * Release reference to text vnode 465 */ 466 if (p->p_textvp) 467 vrele(p->p_textvp); 468 469 /* 470 * Give machine-dependent layer a chance 471 * to free anything that cpu_exit couldn't 472 * release while still running in process context. 473 */ 474 cpu_wait(p); 475 pool_put(&proc_pool, p); 476 nprocs--; 477 return (0); 478 } 479 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 480 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 481 p->p_flag |= P_WAITED; 482 retval[0] = p->p_pid; 483 484 if (SCARG(uap, status)) { 485 status = W_STOPCODE(p->p_xstat); 486 error = copyout((caddr_t)&status, 487 (caddr_t)SCARG(uap, status), 488 sizeof(status)); 489 } else 490 error = 0; 491 return (error); 492 } 493 } 494 if (nfound == 0) 495 return (ECHILD); 496 if (SCARG(uap, options) & WNOHANG) { 497 retval[0] = 0; 498 return (0); 499 } 500 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 501 return (error); 502 goto loop; 503 } 504 505 /* 506 * make process 'parent' the new parent of process 'child'. 507 */ 508 void 509 proc_reparent(child, parent) 510 register struct proc *child; 511 register struct proc *parent; 512 { 513 514 if (child->p_pptr == parent) 515 return; 516 517 LIST_REMOVE(child, p_sibling); 518 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 519 child->p_pptr = parent; 520 } 521
Indexes created Mon Sep 22 13:09:51 GMT 2025