1 /* $OpenBSD: kern_exit.c,v 1.42 2002/05/16 16:16:51 provos 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 void proc_zap(struct proc *); 85 86 /* 87 * exit -- 88 * Death of process. 89 */ 90 int 91 sys_exit(p, v, retval) 92 struct proc *p; 93 void *v; 94 register_t *retval; 95 { 96 struct sys_exit_args /* { 97 syscallarg(int) rval; 98 } */ *uap = v; 99 100 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 101 /* NOTREACHED */ 102 return (0); 103 } 104 105 /* 106 * Exit: deallocate address space and other resources, change proc state 107 * to zombie, and unlink proc from allproc and parent's lists. Save exit 108 * status and rusage for wait(). Check for child processes and orphan them. 109 */ 110 void 111 exit1(p, rv) 112 struct proc *p; 113 int rv; 114 { 115 struct proc *q, *nq; 116 struct vmspace *vm; 117 118 if (p->p_pid == 1) 119 panic("init died (signal %d, exit %d)", 120 WTERMSIG(rv), WEXITSTATUS(rv)); 121 122 if (p->p_flag & P_PROFIL) 123 stopprofclock(p); 124 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 125 /* 126 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 127 * wake up the parent early to avoid deadlock. 128 */ 129 p->p_flag |= P_WEXIT; 130 p->p_flag &= ~P_TRACED; 131 if (p->p_flag & P_PPWAIT) { 132 p->p_flag &= ~P_PPWAIT; 133 wakeup((caddr_t)p->p_pptr); 134 } 135 p->p_sigignore = ~0; 136 p->p_siglist = 0; 137 timeout_del(&p->p_realit_to); 138 139 /* 140 * Close open files and release open-file table. 141 * This may block! 142 */ 143 fdfree(p); 144 145 /* The next three chunks should probably be moved to vmspace_exit. */ 146 vm = p->p_vmspace; 147 #ifdef SYSVSEM 148 semexit(p); 149 #endif 150 /* 151 * Release user portion of address space. 152 * This releases references to vnodes, 153 * which could cause I/O if the file has been unlinked. 154 * Need to do this early enough that we can still sleep. 155 * Can't free the entire vmspace as the kernel stack 156 * may be mapped within that space also. 157 */ 158 if (vm->vm_refcnt == 1) 159 (void) uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 160 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 161 162 if (SESS_LEADER(p)) { 163 register struct session *sp = p->p_session; 164 165 if (sp->s_ttyvp) { 166 /* 167 * Controlling process. 168 * Signal foreground pgrp, 169 * drain controlling terminal 170 * and revoke access to controlling terminal. 171 */ 172 if (sp->s_ttyp->t_session == sp) { 173 if (sp->s_ttyp->t_pgrp) 174 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 175 (void) ttywait(sp->s_ttyp); 176 /* 177 * The tty could have been revoked 178 * if we blocked. 179 */ 180 if (sp->s_ttyvp) 181 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 182 } 183 if (sp->s_ttyvp) 184 vrele(sp->s_ttyvp); 185 sp->s_ttyvp = NULL; 186 /* 187 * s_ttyp is not zero'd; we use this to indicate 188 * that the session once had a controlling terminal. 189 * (for logging and informational purposes) 190 */ 191 } 192 sp->s_leader = NULL; 193 } 194 fixjobc(p, p->p_pgrp, 0); 195 (void)acct_process(p); 196 #ifdef KTRACE 197 /* 198 * release trace file 199 */ 200 p->p_traceflag = 0; /* don't trace the vrele() */ 201 if (p->p_tracep) 202 ktrsettracevnode(p, NULL); 203 #endif 204 #if NSYSTRACE > 0 205 if (ISSET(p->p_flag, P_SYSTRACE)) 206 systrace_exit(p); 207 #endif 208 /* 209 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 210 */ 211 p->p_stat = SDEAD; 212 213 /* 214 * Remove proc from pidhash chain so looking it up won't 215 * work. Move it from allproc to zombproc, but do not yet 216 * wake up the reaper. We will put the proc on the 217 * deadproc list later (using the p_hash member), and 218 * wake up the reaper when we do. 219 */ 220 LIST_REMOVE(p, p_hash); 221 LIST_REMOVE(p, p_list); 222 LIST_INSERT_HEAD(&zombproc, p, p_list); 223 224 /* 225 * Give orphaned children to init(8). 226 */ 227 q = p->p_children.lh_first; 228 if (q) /* only need this if any child is S_ZOMB */ 229 wakeup((caddr_t)initproc); 230 for (; q != 0; q = nq) { 231 nq = q->p_sibling.le_next; 232 proc_reparent(q, initproc); 233 /* 234 * Traced processes are killed 235 * since their existence means someone is screwing up. 236 */ 237 if (q->p_flag & P_TRACED) { 238 q->p_flag &= ~P_TRACED; 239 psignal(q, SIGKILL); 240 } 241 } 242 243 /* 244 * Save exit status and final rusage info, adding in child rusage 245 * info and self times. 246 */ 247 p->p_xstat = rv; 248 *p->p_ru = p->p_stats->p_ru; 249 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 250 ruadd(p->p_ru, &p->p_stats->p_cru); 251 252 /* 253 * clear %cpu usage during swap 254 */ 255 p->p_pctcpu = 0; 256 257 /* 258 * notify interested parties of our demise. 259 */ 260 KNOTE(&p->p_klist, NOTE_EXIT); 261 262 /* 263 * Notify parent that we're gone. If we have P_NOZOMBIE or parent has 264 * the P_NOCLDWAIT flag set, notify process 1 instead (and hope it 265 * will handle this situation). 266 */ 267 if ((p->p_flag & P_NOZOMBIE) || (p->p_pptr->p_flag & P_NOCLDWAIT)) { 268 struct proc *pp = p->p_pptr; 269 proc_reparent(p, initproc); 270 /* 271 * If this was the last child of our parent, notify 272 * parent, so in case he was wait(2)ing, he will 273 * continue. 274 */ 275 if (pp->p_children.lh_first == NULL) 276 wakeup((caddr_t)pp); 277 } 278 279 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 280 psignal(p->p_pptr, P_EXITSIG(p)); 281 wakeup((caddr_t)p->p_pptr); 282 283 /* 284 * Notify procfs debugger 285 */ 286 if (p->p_flag & P_FSTRACE) 287 wakeup((caddr_t)p); 288 289 /* 290 * Release the process's signal state. 291 */ 292 sigactsfree(p); 293 294 /* 295 * Clear curproc after we've done all operations 296 * that could block, and before tearing down the rest 297 * of the process state that might be used from clock, etc. 298 * Also, can't clear curproc while we're still runnable, 299 * as we're not on a run queue (we are current, just not 300 * a proper proc any longer!). 301 * 302 * Other substructures are freed from wait(). 303 */ 304 curproc = NULL; 305 limfree(p->p_limit); 306 p->p_limit = NULL; 307 308 /* 309 * Finally, call machine-dependent code to switch to a new 310 * context (possibly the idle context). Once we are no longer 311 * using the dead process's vmspace and stack, exit2() will be 312 * called to schedule those resources to be released by the 313 * reaper thread. 314 * 315 * Note that cpu_exit() will end with a call equivalent to 316 * cpu_switch(), finishing our execution (pun intended). 317 */ 318 cpu_exit(p); 319 } 320 321 /* 322 * We are called from cpu_exit() once it is safe to schedule the 323 * dead process's resources to be freed. 324 * 325 * NOTE: One must be careful with locking in this routine. It's 326 * called from a critical section in machine-dependent code, so 327 * we should refrain from changing any interrupt state. 328 * 329 * We lock the deadproc list (a spin lock), place the proc on that 330 * list (using the p_hash member), and wake up the reaper. 331 */ 332 void 333 exit2(p) 334 struct proc *p; 335 { 336 337 simple_lock(&deadproc_slock); 338 LIST_INSERT_HEAD(&deadproc, p, p_hash); 339 simple_unlock(&deadproc_slock); 340 341 wakeup(&deadproc); 342 } 343 344 /* 345 * Process reaper. This is run by a kernel thread to free the resources 346 * of a dead process. Once the resources are free, the process becomes 347 * a zombie, and the parent is allowed to read the undead's status. 348 */ 349 void 350 reaper() 351 { 352 struct proc *p; 353 354 for (;;) { 355 simple_lock(&deadproc_slock); 356 p = LIST_FIRST(&deadproc); 357 if (p == NULL) { 358 /* No work for us; go to sleep until someone exits. */ 359 simple_unlock(&deadproc_slock); 360 (void) tsleep(&deadproc, PVM, "reaper", 0); 361 continue; 362 } 363 364 /* Remove us from the deadproc list. */ 365 LIST_REMOVE(p, p_hash); 366 simple_unlock(&deadproc_slock); 367 368 /* 369 * Give machine-dependent code a chance to free any 370 * resources it couldn't free while still running on 371 * that process's context. This must be done before 372 * uvm_exit(), in case these resources are in the PCB. 373 */ 374 cpu_wait(p); 375 376 /* 377 * Free the VM resources we're still holding on to. 378 * We must do this from a valid thread because doing 379 * so may block. 380 */ 381 uvm_exit(p); 382 383 /* Process is now a true zombie. */ 384 if ((p->p_flag & P_NOZOMBIE) == 0) { 385 p->p_stat = SZOMB; 386 387 /* Wake up the parent so it can get exit status. */ 388 psignal(p->p_pptr, SIGCHLD); 389 wakeup((caddr_t)p->p_pptr); 390 } else { 391 /* Noone will wait for us. Just zap the process now */ 392 proc_zap(p); 393 } 394 } 395 } 396 397 int 398 sys_wait4(q, v, retval) 399 register struct proc *q; 400 void *v; 401 register_t *retval; 402 { 403 register struct sys_wait4_args /* { 404 syscallarg(int) pid; 405 syscallarg(int *) status; 406 syscallarg(int) options; 407 syscallarg(struct rusage *) rusage; 408 } */ *uap = v; 409 register int nfound; 410 register struct proc *p, *t; 411 int status, error; 412 413 if (SCARG(uap, pid) == 0) 414 SCARG(uap, pid) = -q->p_pgid; 415 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG)) 416 return (EINVAL); 417 418 loop: 419 nfound = 0; 420 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 421 if ((p->p_flag & P_NOZOMBIE) || 422 (SCARG(uap, pid) != WAIT_ANY && 423 p->p_pid != SCARG(uap, pid) && 424 p->p_pgid != -SCARG(uap, pid))) 425 continue; 426 427 /* 428 * Wait for processes with p_exitsig != SIGCHLD processes only 429 * if WALTSIG is set; wait for processes with pexitsig == 430 * SIGCHLD only if WALTSIG is clear. 431 */ 432 if ((SCARG(uap, options) & WALTSIG) ? 433 (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD)) 434 continue; 435 436 nfound++; 437 if (p->p_stat == SZOMB) { 438 retval[0] = p->p_pid; 439 440 if (SCARG(uap, status)) { 441 status = p->p_xstat; /* convert to int */ 442 error = copyout((caddr_t)&status, 443 (caddr_t)SCARG(uap, status), 444 sizeof(status)); 445 if (error) 446 return (error); 447 } 448 if (SCARG(uap, rusage) && 449 (error = copyout((caddr_t)p->p_ru, 450 (caddr_t)SCARG(uap, rusage), 451 sizeof(struct rusage)))) 452 return (error); 453 454 /* 455 * If we got the child via a ptrace 'attach', 456 * we need to give it back to the old parent. 457 */ 458 if (p->p_oppid && (t = pfind(p->p_oppid))) { 459 p->p_oppid = 0; 460 proc_reparent(p, t); 461 if (p->p_exitsig != 0) 462 psignal(t, P_EXITSIG(p)); 463 wakeup((caddr_t)t); 464 return (0); 465 } 466 467 scheduler_wait_hook(q, p); 468 p->p_xstat = 0; 469 ruadd(&q->p_stats->p_cru, p->p_ru); 470 471 proc_zap(p); 472 473 return (0); 474 } 475 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 476 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 477 p->p_flag |= P_WAITED; 478 retval[0] = p->p_pid; 479 480 if (SCARG(uap, status)) { 481 status = W_STOPCODE(p->p_xstat); 482 error = copyout((caddr_t)&status, 483 (caddr_t)SCARG(uap, status), 484 sizeof(status)); 485 } else 486 error = 0; 487 return (error); 488 } 489 } 490 if (nfound == 0) 491 return (ECHILD); 492 if (SCARG(uap, options) & WNOHANG) { 493 retval[0] = 0; 494 return (0); 495 } 496 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 497 return (error); 498 goto loop; 499 } 500 501 /* 502 * make process 'parent' the new parent of process 'child'. 503 */ 504 void 505 proc_reparent(child, parent) 506 register struct proc *child; 507 register struct proc *parent; 508 { 509 510 if (child->p_pptr == parent) 511 return; 512 513 if (parent == initproc) 514 child->p_exitsig = SIGCHLD; 515 516 LIST_REMOVE(child, p_sibling); 517 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 518 child->p_pptr = parent; 519 } 520 521 void 522 proc_zap(p) 523 struct proc *p; 524 { 525 526 pool_put(&rusage_pool, p->p_ru); 527 528 /* 529 * Finally finished with old proc entry. 530 * Unlink it from its process group and free it. 531 */ 532 leavepgrp(p); 533 LIST_REMOVE(p, p_list); /* off zombproc */ 534 LIST_REMOVE(p, p_sibling); 535 536 /* 537 * Decrement the count of procs running with this uid. 538 */ 539 (void)chgproccnt(p->p_cred->p_ruid, -1); 540 541 /* 542 * Free up credentials. 543 */ 544 if (--p->p_cred->p_refcnt == 0) { 545 crfree(p->p_cred->pc_ucred); 546 pool_put(&pcred_pool, p->p_cred); 547 } 548 549 /* 550 * Release reference to text vnode 551 */ 552 if (p->p_textvp) 553 vrele(p->p_textvp); 554 555 pool_put(&proc_pool, p); 556 nprocs--; 557 } 558 559