1 /* $NetBSD: kern_exit.c,v 1.65 1999/03/24 05:51:22 mrg 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_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 register struct proc *p; 151 int rv; 152 { 153 register struct proc *q, *nq; 154 register struct vmspace *vm; 155 156 if (p->p_pid == 1) 157 panic("init died (signal %d, exit %d)", 158 WTERMSIG(rv), WEXITSTATUS(rv)); 159 #ifdef PGINPROF 160 vmsizmon(); 161 #endif 162 if (p->p_flag & P_PROFIL) 163 stopprofclock(p); 164 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 165 /* 166 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 167 * wake up the parent early to avoid deadlock. 168 */ 169 p->p_flag |= P_WEXIT; 170 if (p->p_flag & P_PPWAIT) { 171 p->p_flag &= ~P_PPWAIT; 172 wakeup((caddr_t)p->p_pptr); 173 } 174 sigfillset(&p->p_sigignore); 175 sigemptyset(&p->p_siglist); 176 p->p_sigcheck = 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 (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 register 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 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 240 (void)acct_process(p); 241 #ifdef KTRACE 242 /* 243 * release trace file 244 */ 245 ktrderef(p); 246 #endif 247 /* 248 * Remove proc from allproc queue and pidhash chain. 249 * Unlink from parent's child list. 250 */ 251 LIST_REMOVE(p, p_list); 252 p->p_stat = SZOMB; 253 254 /* 255 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 256 */ 257 258 LIST_REMOVE(p, p_hash); 259 260 q = p->p_children.lh_first; 261 if (q) /* only need this if any child is S_ZOMB */ 262 wakeup((caddr_t)initproc); 263 for (; q != 0; q = nq) { 264 nq = q->p_sibling.le_next; 265 proc_reparent(q, initproc); 266 /* 267 * Traced processes are killed 268 * since their existence means someone is screwing up. 269 */ 270 if (q->p_flag & P_TRACED) { 271 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 272 psignal(q, SIGKILL); 273 } 274 } 275 276 /* 277 * Save exit status and final rusage info, adding in child rusage 278 * info and self times. 279 */ 280 p->p_xstat = rv; 281 *p->p_ru = p->p_stats->p_ru; 282 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 283 ruadd(p->p_ru, &p->p_stats->p_cru); 284 285 /* 286 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 287 * flag set, notify init instead (and hope it will handle 288 * this situation). 289 */ 290 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 291 struct proc *pp = p->p_pptr; 292 proc_reparent(p, initproc); 293 /* 294 * If this was the last child of our parent, notify 295 * parent, so in case he was wait(2)ing, he will 296 * continue. 297 */ 298 if (pp->p_children.lh_first == NULL) 299 wakeup((caddr_t)pp); 300 } 301 302 /* 303 * Clear curproc after we've done all operations 304 * that could block, and before tearing down the rest 305 * of the process state that might be used from clock, etc. 306 * Also, can't clear curproc while we're still runnable, 307 * as we're not on a run queue (we are current, just not 308 * a proper proc any longer!). 309 * 310 * Other substructures are freed from wait(). 311 */ 312 curproc = NULL; 313 if (--p->p_limit->p_refcnt == 0) 314 pool_put(&plimit_pool, p->p_limit); 315 316 /* 317 * Finally, call machine-dependent code to switch to a new 318 * context (possibly the idle context). Once we are no longer 319 * using the dead process's vmspace and stack, exit2() will be 320 * called to schedule those resources to be released by the 321 * reaper thread. 322 * 323 * Note that cpu_exit() will end with a call equivalent to 324 * cpu_switch(), finishing our execution (pun intended). 325 */ 326 cpu_exit(p); 327 } 328 329 /* 330 * We are called from cpu_exit() once it is safe to schedule the 331 * dead process's resources to be freed. 332 */ 333 void 334 exit2(p) 335 struct proc *p; 336 { 337 338 LIST_INSERT_HEAD(&deadproc, p, p_list); 339 wakeup(&deadproc); 340 } 341 342 /* 343 * Process reaper. This is run by a kernel thread to free the resources 344 * of a dead process. Once the resources are free, the process becomes 345 * a zombie, and the parent is allowed to read the undead's status. 346 */ 347 void 348 reaper() 349 { 350 struct proc *p; 351 352 for (;;) { 353 p = LIST_FIRST(&deadproc); 354 if (p == NULL) { 355 /* No work for us; go to sleep until someone exits. */ 356 (void) tsleep(&deadproc, PVM, "reaper", 0); 357 continue; 358 } 359 360 /* Remove us from the deadproc list. */ 361 LIST_REMOVE(p, p_list); 362 363 /* 364 * Free the VM resources we're still holding on to. 365 * We must do this from a valid thread because doing 366 * so may block. 367 */ 368 uvm_exit(p); 369 370 /* Process is now a true zombie. */ 371 LIST_INSERT_HEAD(&zombproc, p, p_list); 372 373 /* Wake up the parent so it can get exit satus. */ 374 if ((p->p_flag & P_FSTRACE) == 0) 375 psignal(p->p_pptr, SIGCHLD); 376 wakeup((caddr_t)p->p_pptr); 377 } 378 } 379 380 int 381 sys_wait4(q, v, retval) 382 register struct proc *q; 383 void *v; 384 register_t *retval; 385 { 386 register struct sys_wait4_args /* { 387 syscallarg(int) pid; 388 syscallarg(int *) status; 389 syscallarg(int) options; 390 syscallarg(struct rusage *) rusage; 391 } */ *uap = v; 392 register int nfound; 393 register struct proc *p, *t; 394 int status, error; 395 396 if (SCARG(uap, pid) == 0) 397 SCARG(uap, pid) = -q->p_pgid; 398 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG)) 399 return (EINVAL); 400 401 loop: 402 nfound = 0; 403 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 404 if (SCARG(uap, pid) != WAIT_ANY && 405 p->p_pid != SCARG(uap, pid) && 406 p->p_pgid != -SCARG(uap, pid)) 407 continue; 408 nfound++; 409 if (p->p_stat == SZOMB) { 410 retval[0] = p->p_pid; 411 412 if (SCARG(uap, status)) { 413 status = p->p_xstat; /* convert to int */ 414 error = copyout((caddr_t)&status, 415 (caddr_t)SCARG(uap, status), 416 sizeof(status)); 417 if (error) 418 return (error); 419 } 420 if (SCARG(uap, rusage) && 421 (error = copyout((caddr_t)p->p_ru, 422 (caddr_t)SCARG(uap, rusage), 423 sizeof(struct rusage)))) 424 return (error); 425 /* 426 * If we got the child via ptrace(2) or procfs, and 427 * the parent is different (meaning the process was 428 * attached, rather than run as a child), then we need 429 * to give it back to the old parent, and send the 430 * parent a SIGCHLD. The rest of the cleanup will be 431 * done when the old parent waits on the child. 432 */ 433 if ((p->p_flag & P_TRACED) && 434 p->p_oppid != p->p_pptr->p_pid) { 435 t = pfind(p->p_oppid); 436 proc_reparent(p, t ? t : initproc); 437 p->p_oppid = 0; 438 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 439 psignal(p->p_pptr, SIGCHLD); 440 wakeup((caddr_t)p->p_pptr); 441 return (0); 442 } 443 scheduler_wait_hook(curproc, p); 444 p->p_xstat = 0; 445 ruadd(&q->p_stats->p_cru, p->p_ru); 446 pool_put(&rusage_pool, p->p_ru); 447 448 /* 449 * Finally finished with old proc entry. 450 * Unlink it from its process group and free it. 451 */ 452 leavepgrp(p); 453 454 LIST_REMOVE(p, p_list); /* off zombproc */ 455 456 LIST_REMOVE(p, p_sibling); 457 458 /* 459 * Decrement the count of procs running with this uid. 460 */ 461 (void)chgproccnt(p->p_cred->p_ruid, -1); 462 463 /* 464 * Free up credentials. 465 */ 466 if (--p->p_cred->p_refcnt == 0) { 467 crfree(p->p_cred->pc_ucred); 468 pool_put(&pcred_pool, p->p_cred); 469 } 470 471 /* 472 * Release reference to text vnode 473 */ 474 if (p->p_textvp) 475 vrele(p->p_textvp); 476 477 /* 478 * Give machine-dependent layer a chance 479 * to free anything that cpu_exit couldn't 480 * release while still running in process context. 481 */ 482 cpu_wait(p); 483 pool_put(&proc_pool, p); 484 nprocs--; 485 return (0); 486 } 487 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 488 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 489 p->p_flag |= P_WAITED; 490 retval[0] = p->p_pid; 491 492 if (SCARG(uap, status)) { 493 status = W_STOPCODE(p->p_xstat); 494 error = copyout((caddr_t)&status, 495 (caddr_t)SCARG(uap, status), 496 sizeof(status)); 497 } else 498 error = 0; 499 return (error); 500 } 501 } 502 if (nfound == 0) 503 return (ECHILD); 504 if (SCARG(uap, options) & WNOHANG) { 505 retval[0] = 0; 506 return (0); 507 } 508 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 509 return (error); 510 goto loop; 511 } 512 513 /* 514 * make process 'parent' the new parent of process 'child'. 515 */ 516 void 517 proc_reparent(child, parent) 518 register struct proc *child; 519 register struct proc *parent; 520 { 521 522 if (child->p_pptr == parent) 523 return; 524 525 LIST_REMOVE(child, p_sibling); 526 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 527 child->p_pptr = parent; 528 } 529