1 /* $OpenBSD: kern_exit.c,v 1.41 2002/03/14 01:27:04 millert 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 <sys/mount.h> 75 #include <sys/syscallargs.h> 76 77 #include <machine/cpu.h> 78 79 #include <uvm/uvm_extern.h> 80 81 void proc_zap(struct proc *); 82 83 /* 84 * exit -- 85 * Death of process. 86 */ 87 int 88 sys_exit(p, v, retval) 89 struct proc *p; 90 void *v; 91 register_t *retval; 92 { 93 struct sys_exit_args /* { 94 syscallarg(int) rval; 95 } */ *uap = v; 96 97 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 98 /* NOTREACHED */ 99 return (0); 100 } 101 102 /* 103 * Exit: deallocate address space and other resources, change proc state 104 * to zombie, and unlink proc from allproc and parent's lists. Save exit 105 * status and rusage for wait(). Check for child processes and orphan them. 106 */ 107 void 108 exit1(p, rv) 109 struct proc *p; 110 int rv; 111 { 112 struct proc *q, *nq; 113 struct vmspace *vm; 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 /* The next three chunks should probably be moved to vmspace_exit. */ 143 vm = p->p_vmspace; 144 #ifdef SYSVSEM 145 semexit(p); 146 #endif 147 /* 148 * Release user portion of address space. 149 * This releases references to vnodes, 150 * which could cause I/O if the file has been unlinked. 151 * Need to do this early enough that we can still sleep. 152 * Can't free the entire vmspace as the kernel stack 153 * may be mapped within that space also. 154 */ 155 if (vm->vm_refcnt == 1) 156 (void) uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 157 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 158 159 if (SESS_LEADER(p)) { 160 register struct session *sp = p->p_session; 161 162 if (sp->s_ttyvp) { 163 /* 164 * Controlling process. 165 * Signal foreground pgrp, 166 * drain controlling terminal 167 * and revoke access to controlling terminal. 168 */ 169 if (sp->s_ttyp->t_session == sp) { 170 if (sp->s_ttyp->t_pgrp) 171 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 172 (void) ttywait(sp->s_ttyp); 173 /* 174 * The tty could have been revoked 175 * if we blocked. 176 */ 177 if (sp->s_ttyvp) 178 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 179 } 180 if (sp->s_ttyvp) 181 vrele(sp->s_ttyvp); 182 sp->s_ttyvp = NULL; 183 /* 184 * s_ttyp is not zero'd; we use this to indicate 185 * that the session once had a controlling terminal. 186 * (for logging and informational purposes) 187 */ 188 } 189 sp->s_leader = NULL; 190 } 191 fixjobc(p, p->p_pgrp, 0); 192 (void)acct_process(p); 193 #ifdef KTRACE 194 /* 195 * release trace file 196 */ 197 p->p_traceflag = 0; /* don't trace the vrele() */ 198 if (p->p_tracep) 199 ktrsettracevnode(p, NULL); 200 #endif 201 /* 202 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 203 */ 204 p->p_stat = SDEAD; 205 206 /* 207 * Remove proc from pidhash chain so looking it up won't 208 * work. Move it from allproc to zombproc, but do not yet 209 * wake up the reaper. We will put the proc on the 210 * deadproc list later (using the p_hash member), and 211 * wake up the reaper when we do. 212 */ 213 LIST_REMOVE(p, p_hash); 214 LIST_REMOVE(p, p_list); 215 LIST_INSERT_HEAD(&zombproc, p, p_list); 216 217 /* 218 * Give orphaned children to init(8). 219 */ 220 q = p->p_children.lh_first; 221 if (q) /* only need this if any child is S_ZOMB */ 222 wakeup((caddr_t)initproc); 223 for (; q != 0; q = nq) { 224 nq = q->p_sibling.le_next; 225 proc_reparent(q, initproc); 226 /* 227 * Traced processes are killed 228 * since their existence means someone is screwing up. 229 */ 230 if (q->p_flag & P_TRACED) { 231 q->p_flag &= ~P_TRACED; 232 psignal(q, SIGKILL); 233 } 234 } 235 236 /* 237 * Save exit status and final rusage info, adding in child rusage 238 * info and self times. 239 */ 240 p->p_xstat = rv; 241 *p->p_ru = p->p_stats->p_ru; 242 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 243 ruadd(p->p_ru, &p->p_stats->p_cru); 244 245 /* 246 * clear %cpu usage during swap 247 */ 248 p->p_pctcpu = 0; 249 250 /* 251 * notify interested parties of our demise. 252 */ 253 KNOTE(&p->p_klist, NOTE_EXIT); 254 255 /* 256 * Notify parent that we're gone. If we have P_NOZOMBIE or parent has 257 * the P_NOCLDWAIT flag set, notify process 1 instead (and hope it 258 * will handle this situation). 259 */ 260 if ((p->p_flag & P_NOZOMBIE) || (p->p_pptr->p_flag & P_NOCLDWAIT)) { 261 struct proc *pp = p->p_pptr; 262 proc_reparent(p, initproc); 263 /* 264 * If this was the last child of our parent, notify 265 * parent, so in case he was wait(2)ing, he will 266 * continue. 267 */ 268 if (pp->p_children.lh_first == NULL) 269 wakeup((caddr_t)pp); 270 } 271 272 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 273 psignal(p->p_pptr, P_EXITSIG(p)); 274 wakeup((caddr_t)p->p_pptr); 275 276 /* 277 * Notify procfs debugger 278 */ 279 if (p->p_flag & P_FSTRACE) 280 wakeup((caddr_t)p); 281 282 /* 283 * Release the process's signal state. 284 */ 285 sigactsfree(p); 286 287 /* 288 * Clear curproc after we've done all operations 289 * that could block, and before tearing down the rest 290 * of the process state that might be used from clock, etc. 291 * Also, can't clear curproc while we're still runnable, 292 * as we're not on a run queue (we are current, just not 293 * a proper proc any longer!). 294 * 295 * Other substructures are freed from wait(). 296 */ 297 curproc = NULL; 298 limfree(p->p_limit); 299 p->p_limit = NULL; 300 301 /* 302 * Finally, call machine-dependent code to switch to a new 303 * context (possibly the idle context). Once we are no longer 304 * using the dead process's vmspace and stack, exit2() will be 305 * called to schedule those resources to be released by the 306 * reaper thread. 307 * 308 * Note that cpu_exit() will end with a call equivalent to 309 * cpu_switch(), finishing our execution (pun intended). 310 */ 311 cpu_exit(p); 312 } 313 314 /* 315 * We are called from cpu_exit() once it is safe to schedule the 316 * dead process's resources to be freed. 317 * 318 * NOTE: One must be careful with locking in this routine. It's 319 * called from a critical section in machine-dependent code, so 320 * we should refrain from changing any interrupt state. 321 * 322 * We lock the deadproc list (a spin lock), place the proc on that 323 * list (using the p_hash member), and wake up the reaper. 324 */ 325 void 326 exit2(p) 327 struct proc *p; 328 { 329 330 simple_lock(&deadproc_slock); 331 LIST_INSERT_HEAD(&deadproc, p, p_hash); 332 simple_unlock(&deadproc_slock); 333 334 wakeup(&deadproc); 335 } 336 337 /* 338 * Process reaper. This is run by a kernel thread to free the resources 339 * of a dead process. Once the resources are free, the process becomes 340 * a zombie, and the parent is allowed to read the undead's status. 341 */ 342 void 343 reaper() 344 { 345 struct proc *p; 346 347 for (;;) { 348 simple_lock(&deadproc_slock); 349 p = LIST_FIRST(&deadproc); 350 if (p == NULL) { 351 /* No work for us; go to sleep until someone exits. */ 352 simple_unlock(&deadproc_slock); 353 (void) tsleep(&deadproc, PVM, "reaper", 0); 354 continue; 355 } 356 357 /* Remove us from the deadproc list. */ 358 LIST_REMOVE(p, p_hash); 359 simple_unlock(&deadproc_slock); 360 361 /* 362 * Give machine-dependent code a chance to free any 363 * resources it couldn't free while still running on 364 * that process's context. This must be done before 365 * uvm_exit(), in case these resources are in the PCB. 366 */ 367 cpu_wait(p); 368 369 /* 370 * Free the VM resources we're still holding on to. 371 * We must do this from a valid thread because doing 372 * so may block. 373 */ 374 uvm_exit(p); 375 376 /* Process is now a true zombie. */ 377 if ((p->p_flag & P_NOZOMBIE) == 0) { 378 p->p_stat = SZOMB; 379 380 /* Wake up the parent so it can get exit status. */ 381 psignal(p->p_pptr, SIGCHLD); 382 wakeup((caddr_t)p->p_pptr); 383 } else { 384 /* Noone will wait for us. Just zap the process now */ 385 proc_zap(p); 386 } 387 } 388 } 389 390 int 391 sys_wait4(q, v, retval) 392 register struct proc *q; 393 void *v; 394 register_t *retval; 395 { 396 register struct sys_wait4_args /* { 397 syscallarg(int) pid; 398 syscallarg(int *) status; 399 syscallarg(int) options; 400 syscallarg(struct rusage *) rusage; 401 } */ *uap = v; 402 register int nfound; 403 register struct proc *p, *t; 404 int status, error; 405 406 if (SCARG(uap, pid) == 0) 407 SCARG(uap, pid) = -q->p_pgid; 408 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG)) 409 return (EINVAL); 410 411 loop: 412 nfound = 0; 413 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 414 if ((p->p_flag & P_NOZOMBIE) || 415 (SCARG(uap, pid) != WAIT_ANY && 416 p->p_pid != SCARG(uap, pid) && 417 p->p_pgid != -SCARG(uap, pid))) 418 continue; 419 420 /* 421 * Wait for processes with p_exitsig != SIGCHLD processes only 422 * if WALTSIG is set; wait for processes with pexitsig == 423 * SIGCHLD only if WALTSIG is clear. 424 */ 425 if ((SCARG(uap, options) & WALTSIG) ? 426 (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD)) 427 continue; 428 429 nfound++; 430 if (p->p_stat == SZOMB) { 431 retval[0] = p->p_pid; 432 433 if (SCARG(uap, status)) { 434 status = p->p_xstat; /* convert to int */ 435 error = copyout((caddr_t)&status, 436 (caddr_t)SCARG(uap, status), 437 sizeof(status)); 438 if (error) 439 return (error); 440 } 441 if (SCARG(uap, rusage) && 442 (error = copyout((caddr_t)p->p_ru, 443 (caddr_t)SCARG(uap, rusage), 444 sizeof(struct rusage)))) 445 return (error); 446 447 /* 448 * If we got the child via a ptrace 'attach', 449 * we need to give it back to the old parent. 450 */ 451 if (p->p_oppid && (t = pfind(p->p_oppid))) { 452 p->p_oppid = 0; 453 proc_reparent(p, t); 454 if (p->p_exitsig != 0) 455 psignal(t, P_EXITSIG(p)); 456 wakeup((caddr_t)t); 457 return (0); 458 } 459 460 scheduler_wait_hook(q, p); 461 p->p_xstat = 0; 462 ruadd(&q->p_stats->p_cru, p->p_ru); 463 464 proc_zap(p); 465 466 return (0); 467 } 468 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 469 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 470 p->p_flag |= P_WAITED; 471 retval[0] = p->p_pid; 472 473 if (SCARG(uap, status)) { 474 status = W_STOPCODE(p->p_xstat); 475 error = copyout((caddr_t)&status, 476 (caddr_t)SCARG(uap, status), 477 sizeof(status)); 478 } else 479 error = 0; 480 return (error); 481 } 482 } 483 if (nfound == 0) 484 return (ECHILD); 485 if (SCARG(uap, options) & WNOHANG) { 486 retval[0] = 0; 487 return (0); 488 } 489 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 490 return (error); 491 goto loop; 492 } 493 494 /* 495 * make process 'parent' the new parent of process 'child'. 496 */ 497 void 498 proc_reparent(child, parent) 499 register struct proc *child; 500 register struct proc *parent; 501 { 502 503 if (child->p_pptr == parent) 504 return; 505 506 if (parent == initproc) 507 child->p_exitsig = SIGCHLD; 508 509 LIST_REMOVE(child, p_sibling); 510 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 511 child->p_pptr = parent; 512 } 513 514 void 515 proc_zap(p) 516 struct proc *p; 517 { 518 519 pool_put(&rusage_pool, p->p_ru); 520 521 /* 522 * Finally finished with old proc entry. 523 * Unlink it from its process group and free it. 524 */ 525 leavepgrp(p); 526 LIST_REMOVE(p, p_list); /* off zombproc */ 527 LIST_REMOVE(p, p_sibling); 528 529 /* 530 * Decrement the count of procs running with this uid. 531 */ 532 (void)chgproccnt(p->p_cred->p_ruid, -1); 533 534 /* 535 * Free up credentials. 536 */ 537 if (--p->p_cred->p_refcnt == 0) { 538 crfree(p->p_cred->pc_ucred); 539 pool_put(&pcred_pool, p->p_cred); 540 } 541 542 /* 543 * Release reference to text vnode 544 */ 545 if (p->p_textvp) 546 vrele(p->p_textvp); 547 548 pool_put(&proc_pool, p); 549 nprocs--; 550 } 551 552