1 /* $OpenBSD: kern_exit.c,v 1.43 2002/10/29 01:32:16 art Exp $ */ 2 /* $NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1989, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/ioctl.h> 47 #include <sys/proc.h> 48 #include <sys/tty.h> 49 #include <sys/time.h> 50 #include <sys/resource.h> 51 #include <sys/kernel.h> 52 #include <sys/proc.h> 53 #include <sys/buf.h> 54 #include <sys/wait.h> 55 #include <sys/file.h> 56 #include <sys/vnode.h> 57 #include <sys/syslog.h> 58 #include <sys/malloc.h> 59 #include <sys/resourcevar.h> 60 #include <sys/ptrace.h> 61 #include <sys/acct.h> 62 #include <sys/filedesc.h> 63 #include <sys/signalvar.h> 64 #include <sys/sched.h> 65 #include <sys/ktrace.h> 66 #include <sys/pool.h> 67 #ifdef SYSVSHM 68 #include <sys/shm.h> 69 #endif 70 #ifdef SYSVSEM 71 #include <sys/sem.h> 72 #endif 73 74 #include "systrace.h" 75 #include <dev/systrace.h> 76 77 #include <sys/mount.h> 78 #include <sys/syscallargs.h> 79 80 #include <machine/cpu.h> 81 82 #include <uvm/uvm_extern.h> 83 84 /* 85 * exit -- 86 * Death of process. 87 */ 88 int 89 sys_exit(p, v, retval) 90 struct proc *p; 91 void *v; 92 register_t *retval; 93 { 94 struct sys_exit_args /* { 95 syscallarg(int) rval; 96 } */ *uap = v; 97 98 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 99 /* NOTREACHED */ 100 return (0); 101 } 102 103 /* 104 * Exit: deallocate address space and other resources, change proc state 105 * to zombie, and unlink proc from allproc and parent's lists. Save exit 106 * status and rusage for wait(). Check for child processes and orphan them. 107 */ 108 void 109 exit1(p, rv) 110 struct proc *p; 111 int rv; 112 { 113 struct proc *q, *nq; 114 115 if (p->p_pid == 1) 116 panic("init died (signal %d, exit %d)", 117 WTERMSIG(rv), WEXITSTATUS(rv)); 118 119 if (p->p_flag & P_PROFIL) 120 stopprofclock(p); 121 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 122 /* 123 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 124 * wake up the parent early to avoid deadlock. 125 */ 126 p->p_flag |= P_WEXIT; 127 p->p_flag &= ~P_TRACED; 128 if (p->p_flag & P_PPWAIT) { 129 p->p_flag &= ~P_PPWAIT; 130 wakeup((caddr_t)p->p_pptr); 131 } 132 p->p_sigignore = ~0; 133 p->p_siglist = 0; 134 timeout_del(&p->p_realit_to); 135 136 /* 137 * Close open files and release open-file table. 138 * This may block! 139 */ 140 fdfree(p); 141 142 #ifdef SYSVSEM 143 semexit(p); 144 #endif 145 if (SESS_LEADER(p)) { 146 register struct session *sp = p->p_session; 147 148 if (sp->s_ttyvp) { 149 /* 150 * Controlling process. 151 * Signal foreground pgrp, 152 * drain controlling terminal 153 * and revoke access to controlling terminal. 154 */ 155 if (sp->s_ttyp->t_session == sp) { 156 if (sp->s_ttyp->t_pgrp) 157 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 158 (void) ttywait(sp->s_ttyp); 159 /* 160 * The tty could have been revoked 161 * if we blocked. 162 */ 163 if (sp->s_ttyvp) 164 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 165 } 166 if (sp->s_ttyvp) 167 vrele(sp->s_ttyvp); 168 sp->s_ttyvp = NULL; 169 /* 170 * s_ttyp is not zero'd; we use this to indicate 171 * that the session once had a controlling terminal. 172 * (for logging and informational purposes) 173 */ 174 } 175 sp->s_leader = NULL; 176 } 177 fixjobc(p, p->p_pgrp, 0); 178 (void)acct_process(p); 179 #ifdef KTRACE 180 /* 181 * release trace file 182 */ 183 p->p_traceflag = 0; /* don't trace the vrele() */ 184 if (p->p_tracep) 185 ktrsettracevnode(p, NULL); 186 #endif 187 #if NSYSTRACE > 0 188 if (ISSET(p->p_flag, P_SYSTRACE)) 189 systrace_exit(p); 190 #endif 191 /* 192 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 193 */ 194 p->p_stat = SDEAD; 195 196 /* 197 * Remove proc from pidhash chain so looking it up won't 198 * work. Move it from allproc to zombproc, but do not yet 199 * wake up the reaper. We will put the proc on the 200 * deadproc list later (using the p_hash member), and 201 * wake up the reaper when we do. 202 */ 203 LIST_REMOVE(p, p_hash); 204 LIST_REMOVE(p, p_list); 205 LIST_INSERT_HEAD(&zombproc, p, p_list); 206 207 /* 208 * Give orphaned children to init(8). 209 */ 210 q = p->p_children.lh_first; 211 if (q) /* only need this if any child is S_ZOMB */ 212 wakeup((caddr_t)initproc); 213 for (; q != 0; q = nq) { 214 nq = q->p_sibling.le_next; 215 proc_reparent(q, initproc); 216 /* 217 * Traced processes are killed 218 * since their existence means someone is screwing up. 219 */ 220 if (q->p_flag & P_TRACED) { 221 q->p_flag &= ~P_TRACED; 222 psignal(q, SIGKILL); 223 } 224 } 225 226 /* 227 * Save exit status and final rusage info, adding in child rusage 228 * info and self times. 229 */ 230 p->p_xstat = rv; 231 *p->p_ru = p->p_stats->p_ru; 232 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 233 ruadd(p->p_ru, &p->p_stats->p_cru); 234 235 /* 236 * clear %cpu usage during swap 237 */ 238 p->p_pctcpu = 0; 239 240 /* 241 * notify interested parties of our demise. 242 */ 243 KNOTE(&p->p_klist, NOTE_EXIT); 244 245 /* 246 * Notify parent that we're gone. If we have P_NOZOMBIE or parent has 247 * the P_NOCLDWAIT flag set, notify process 1 instead (and hope it 248 * will handle this situation). 249 */ 250 if ((p->p_flag & P_NOZOMBIE) || (p->p_pptr->p_flag & P_NOCLDWAIT)) { 251 struct proc *pp = p->p_pptr; 252 proc_reparent(p, initproc); 253 /* 254 * If this was the last child of our parent, notify 255 * parent, so in case he was wait(2)ing, he will 256 * continue. 257 */ 258 if (pp->p_children.lh_first == NULL) 259 wakeup((caddr_t)pp); 260 } 261 262 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 263 psignal(p->p_pptr, P_EXITSIG(p)); 264 wakeup((caddr_t)p->p_pptr); 265 266 /* 267 * Notify procfs debugger 268 */ 269 if (p->p_flag & P_FSTRACE) 270 wakeup((caddr_t)p); 271 272 /* 273 * Release the process's signal state. 274 */ 275 sigactsfree(p); 276 277 /* 278 * Clear curproc after we've done all operations 279 * that could block, and before tearing down the rest 280 * of the process state that might be used from clock, etc. 281 * Also, can't clear curproc while we're still runnable, 282 * as we're not on a run queue (we are current, just not 283 * a proper proc any longer!). 284 * 285 * Other substructures are freed from wait(). 286 */ 287 curproc = NULL; 288 limfree(p->p_limit); 289 p->p_limit = NULL; 290 291 /* 292 * Finally, call machine-dependent code to switch to a new 293 * context (possibly the idle context). Once we are no longer 294 * using the dead process's vmspace and stack, exit2() will be 295 * called to schedule those resources to be released by the 296 * reaper thread. 297 * 298 * Note that cpu_exit() will end with a call equivalent to 299 * cpu_switch(), finishing our execution (pun intended). 300 */ 301 cpu_exit(p); 302 } 303 304 /* 305 * We are called from cpu_exit() once it is safe to schedule the 306 * dead process's resources to be freed. 307 * 308 * NOTE: One must be careful with locking in this routine. It's 309 * called from a critical section in machine-dependent code, so 310 * we should refrain from changing any interrupt state. 311 * 312 * We lock the deadproc list (a spin lock), place the proc on that 313 * list (using the p_hash member), and wake up the reaper. 314 */ 315 void 316 exit2(p) 317 struct proc *p; 318 { 319 320 simple_lock(&deadproc_slock); 321 LIST_INSERT_HEAD(&deadproc, p, p_hash); 322 simple_unlock(&deadproc_slock); 323 324 wakeup(&deadproc); 325 } 326 327 /* 328 * Process reaper. This is run by a kernel thread to free the resources 329 * of a dead process. Once the resources are free, the process becomes 330 * a zombie, and the parent is allowed to read the undead's status. 331 */ 332 void 333 reaper(void) 334 { 335 struct proc *p; 336 337 for (;;) { 338 simple_lock(&deadproc_slock); 339 p = LIST_FIRST(&deadproc); 340 if (p == NULL) { 341 /* No work for us; go to sleep until someone exits. */ 342 simple_unlock(&deadproc_slock); 343 (void) tsleep(&deadproc, PVM, "reaper", 0); 344 continue; 345 } 346 347 /* Remove us from the deadproc list. */ 348 LIST_REMOVE(p, p_hash); 349 simple_unlock(&deadproc_slock); 350 351 /* 352 * Give machine-dependent code a chance to free any 353 * resources it couldn't free while still running on 354 * that process's context. This must be done before 355 * uvm_exit(), in case these resources are in the PCB. 356 */ 357 cpu_wait(p); 358 359 /* 360 * Free the VM resources we're still holding on to. 361 * We must do this from a valid thread because doing 362 * so may block. 363 */ 364 uvm_exit(p); 365 366 /* Process is now a true zombie. */ 367 if ((p->p_flag & P_NOZOMBIE) == 0) { 368 p->p_stat = SZOMB; 369 370 /* Wake up the parent so it can get exit status. */ 371 psignal(p->p_pptr, SIGCHLD); 372 wakeup((caddr_t)p->p_pptr); 373 } else { 374 /* Noone will wait for us. Just zap the process now */ 375 proc_zap(p); 376 } 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|WALTSIG)) 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 ((p->p_flag & P_NOZOMBIE) || 405 (SCARG(uap, pid) != WAIT_ANY && 406 p->p_pid != SCARG(uap, pid) && 407 p->p_pgid != -SCARG(uap, pid))) 408 continue; 409 410 /* 411 * Wait for processes with p_exitsig != SIGCHLD processes only 412 * if WALTSIG is set; wait for processes with pexitsig == 413 * SIGCHLD only if WALTSIG is clear. 414 */ 415 if ((SCARG(uap, options) & WALTSIG) ? 416 (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD)) 417 continue; 418 419 nfound++; 420 if (p->p_stat == SZOMB) { 421 retval[0] = p->p_pid; 422 423 if (SCARG(uap, status)) { 424 status = p->p_xstat; /* convert to int */ 425 error = copyout((caddr_t)&status, 426 (caddr_t)SCARG(uap, status), 427 sizeof(status)); 428 if (error) 429 return (error); 430 } 431 if (SCARG(uap, rusage) && 432 (error = copyout((caddr_t)p->p_ru, 433 (caddr_t)SCARG(uap, rusage), 434 sizeof(struct rusage)))) 435 return (error); 436 437 /* 438 * If we got the child via a ptrace 'attach', 439 * we need to give it back to the old parent. 440 */ 441 if (p->p_oppid && (t = pfind(p->p_oppid))) { 442 p->p_oppid = 0; 443 proc_reparent(p, t); 444 if (p->p_exitsig != 0) 445 psignal(t, P_EXITSIG(p)); 446 wakeup((caddr_t)t); 447 return (0); 448 } 449 450 scheduler_wait_hook(q, p); 451 p->p_xstat = 0; 452 ruadd(&q->p_stats->p_cru, p->p_ru); 453 454 proc_zap(p); 455 456 return (0); 457 } 458 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 459 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 460 p->p_flag |= P_WAITED; 461 retval[0] = p->p_pid; 462 463 if (SCARG(uap, status)) { 464 status = W_STOPCODE(p->p_xstat); 465 error = copyout((caddr_t)&status, 466 (caddr_t)SCARG(uap, status), 467 sizeof(status)); 468 } else 469 error = 0; 470 return (error); 471 } 472 } 473 if (nfound == 0) 474 return (ECHILD); 475 if (SCARG(uap, options) & WNOHANG) { 476 retval[0] = 0; 477 return (0); 478 } 479 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 480 return (error); 481 goto loop; 482 } 483 484 /* 485 * make process 'parent' the new parent of process 'child'. 486 */ 487 void 488 proc_reparent(child, parent) 489 register struct proc *child; 490 register struct proc *parent; 491 { 492 493 if (child->p_pptr == parent) 494 return; 495 496 if (parent == initproc) 497 child->p_exitsig = SIGCHLD; 498 499 LIST_REMOVE(child, p_sibling); 500 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 501 child->p_pptr = parent; 502 } 503 504 void 505 proc_zap(struct proc *p) 506 { 507 pool_put(&rusage_pool, p->p_ru); 508 509 /* 510 * Finally finished with old proc entry. 511 * Unlink it from its process group and free it. 512 */ 513 leavepgrp(p); 514 LIST_REMOVE(p, p_list); /* off zombproc */ 515 LIST_REMOVE(p, p_sibling); 516 517 /* 518 * Decrement the count of procs running with this uid. 519 */ 520 (void)chgproccnt(p->p_cred->p_ruid, -1); 521 522 /* 523 * Free up credentials. 524 */ 525 if (--p->p_cred->p_refcnt == 0) { 526 crfree(p->p_cred->pc_ucred); 527 pool_put(&pcred_pool, p->p_cred); 528 } 529 530 /* 531 * Release reference to text vnode 532 */ 533 if (p->p_textvp) 534 vrele(p->p_textvp); 535 536 pool_put(&proc_pool, p); 537 nprocs--; 538 } 539 540