1 /* $NetBSD: kern_exit.c,v 1.94 2002/06/17 16:22:50 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 1999 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 <sys/cdefs.h> 81 __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.94 2002/06/17 16:22:50 christos Exp $"); 82 83 #include "opt_ktrace.h" 84 #include "opt_systrace.h" 85 #include "opt_sysv.h" 86 87 #include <sys/param.h> 88 #include <sys/systm.h> 89 #include <sys/map.h> 90 #include <sys/ioctl.h> 91 #include <sys/proc.h> 92 #include <sys/tty.h> 93 #include <sys/time.h> 94 #include <sys/resource.h> 95 #include <sys/kernel.h> 96 #include <sys/ktrace.h> 97 #include <sys/proc.h> 98 #include <sys/buf.h> 99 #include <sys/wait.h> 100 #include <sys/file.h> 101 #include <sys/vnode.h> 102 #include <sys/syslog.h> 103 #include <sys/malloc.h> 104 #include <sys/pool.h> 105 #include <sys/resourcevar.h> 106 #include <sys/ptrace.h> 107 #include <sys/acct.h> 108 #include <sys/filedesc.h> 109 #include <sys/signalvar.h> 110 #include <sys/sched.h> 111 #include <sys/mount.h> 112 #include <sys/syscallargs.h> 113 #include <sys/systrace.h> 114 115 #include <machine/cpu.h> 116 117 #include <uvm/uvm_extern.h> 118 119 120 /* 121 * exit -- 122 * Death of process. 123 */ 124 int 125 sys_exit(struct proc *p, void *v, register_t *retval) 126 { 127 struct sys_exit_args /* { 128 syscallarg(int) rval; 129 } */ *uap = v; 130 131 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 132 /* NOTREACHED */ 133 return (0); 134 } 135 136 /* 137 * Exit: deallocate address space and other resources, change proc state 138 * to zombie, and unlink proc from allproc and parent's lists. Save exit 139 * status and rusage for wait(). Check for child processes and orphan them. 140 */ 141 void 142 exit1(struct proc *p, int rv) 143 { 144 struct proc *q, *nq; 145 int s; 146 147 if (__predict_false(p == initproc)) 148 panic("init died (signal %d, exit %d)", 149 WTERMSIG(rv), WEXITSTATUS(rv)); 150 151 #ifdef PGINPROF 152 vmsizmon(); 153 #endif 154 if (p->p_flag & P_PROFIL) 155 stopprofclock(p); 156 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 157 /* 158 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 159 * wake up the parent early to avoid deadlock. 160 */ 161 p->p_flag |= P_WEXIT; 162 if (p->p_flag & P_PPWAIT) { 163 p->p_flag &= ~P_PPWAIT; 164 wakeup((caddr_t)p->p_pptr); 165 } 166 sigfillset(&p->p_sigctx.ps_sigignore); 167 sigemptyset(&p->p_sigctx.ps_siglist); 168 p->p_sigctx.ps_sigcheck = 0; 169 callout_stop(&p->p_realit_ch); 170 171 /* 172 * Close open files and release open-file table. 173 * This may block! 174 */ 175 fdfree(p); 176 cwdfree(p); 177 178 doexithooks(p); 179 180 if (SESS_LEADER(p)) { 181 struct session *sp = p->p_session; 182 183 if (sp->s_ttyvp) { 184 /* 185 * Controlling process. 186 * Signal foreground pgrp, 187 * drain controlling terminal 188 * and revoke access to controlling terminal. 189 */ 190 if (sp->s_ttyp->t_session == sp) { 191 if (sp->s_ttyp->t_pgrp) 192 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 193 (void) ttywait(sp->s_ttyp); 194 /* 195 * The tty could have been revoked 196 * if we blocked. 197 */ 198 if (sp->s_ttyvp) 199 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 200 } 201 if (sp->s_ttyvp) 202 vrele(sp->s_ttyvp); 203 sp->s_ttyvp = NULL; 204 /* 205 * s_ttyp is not zero'd; we use this to indicate 206 * that the session once had a controlling terminal. 207 * (for logging and informational purposes) 208 */ 209 } 210 sp->s_leader = NULL; 211 } 212 fixjobc(p, p->p_pgrp, 0); 213 (void)acct_process(p); 214 #ifdef KTRACE 215 /* 216 * release trace file 217 */ 218 ktrderef(p); 219 #endif 220 #ifdef SYSTRACE 221 systrace_sys_exit(p); 222 #endif 223 /* 224 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 225 */ 226 p->p_stat = SDEAD; 227 228 /* 229 * Remove proc from pidhash chain so looking it up won't 230 * work. Move it from allproc to zombproc, but do not yet 231 * wake up the reaper. We will put the proc on the 232 * deadproc list later (using the p_hash member), and 233 * wake up the reaper when we do. 234 */ 235 s = proclist_lock_write(); 236 LIST_REMOVE(p, p_hash); 237 LIST_REMOVE(p, p_list); 238 LIST_INSERT_HEAD(&zombproc, p, p_list); 239 proclist_unlock_write(s); 240 241 /* 242 * Give orphaned children to init(8). 243 */ 244 q = p->p_children.lh_first; 245 if (q) /* only need this if any child is S_ZOMB */ 246 wakeup((caddr_t)initproc); 247 for (; q != 0; q = nq) { 248 nq = q->p_sibling.le_next; 249 proc_reparent(q, initproc); 250 /* 251 * Traced processes are killed 252 * since their existence means someone is screwing up. 253 */ 254 if (q->p_flag & P_TRACED) { 255 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 256 psignal(q, SIGKILL); 257 } 258 } 259 260 /* 261 * Save exit status and final rusage info, adding in child rusage 262 * info and self times. 263 */ 264 p->p_xstat = rv; 265 *p->p_ru = p->p_stats->p_ru; 266 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 267 ruadd(p->p_ru, &p->p_stats->p_cru); 268 269 /* 270 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 271 * flag set, notify init instead (and hope it will handle 272 * this situation). 273 */ 274 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 275 struct proc *pp = p->p_pptr; 276 proc_reparent(p, initproc); 277 /* 278 * If this was the last child of our parent, notify 279 * parent, so in case he was wait(2)ing, he will 280 * continue. 281 */ 282 if (pp->p_children.lh_first == NULL) 283 wakeup((caddr_t)pp); 284 } 285 286 /* 287 * Release the process's signal state. 288 */ 289 sigactsfree(p); 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 limfree(p->p_limit); 303 p->p_limit = NULL; 304 305 /* 306 * If emulation has process exit hook, call it now. 307 */ 308 if (p->p_emul->e_proc_exit) 309 (*p->p_emul->e_proc_exit)(p); 310 311 /* This process no longer needs to hold the kernel lock. */ 312 KERNEL_PROC_UNLOCK(p); 313 314 /* 315 * Finally, call machine-dependent code to switch to a new 316 * context (possibly the idle context). Once we are no longer 317 * using the dead process's vmspace and stack, exit2() will be 318 * called to schedule those resources to be released by the 319 * reaper thread. 320 * 321 * Note that cpu_exit() will end with a call equivalent to 322 * cpu_switch(), finishing our execution (pun intended). 323 */ 324 cpu_exit(p); 325 } 326 327 /* 328 * We are called from cpu_exit() once it is safe to schedule the 329 * dead process's resources to be freed (i.e., once we've switched to 330 * the idle PCB for the current CPU). 331 * 332 * NOTE: One must be careful with locking in this routine. It's 333 * called from a critical section in machine-dependent code, so 334 * we should refrain from changing any interrupt state. 335 * 336 * We lock the deadproc list (a spin lock), place the proc on that 337 * list (using the p_hash member), and wake up the reaper. 338 */ 339 void 340 exit2(struct proc *p) 341 { 342 343 simple_lock(&deadproc_slock); 344 LIST_INSERT_HEAD(&deadproc, p, p_hash); 345 simple_unlock(&deadproc_slock); 346 347 wakeup(&deadproc); 348 } 349 350 /* 351 * Process reaper. This is run by a kernel thread to free the resources 352 * of a dead process. Once the resources are free, the process becomes 353 * a zombie, and the parent is allowed to read the undead's status. 354 */ 355 void 356 reaper(void *arg) 357 { 358 struct proc *p; 359 360 KERNEL_PROC_UNLOCK(curproc); 361 362 for (;;) { 363 simple_lock(&deadproc_slock); 364 p = LIST_FIRST(&deadproc); 365 if (p == NULL) { 366 /* No work for us; go to sleep until someone exits. */ 367 (void) ltsleep(&deadproc, PVM|PNORELOCK, 368 "reaper", 0, &deadproc_slock); 369 continue; 370 } 371 372 /* Remove us from the deadproc list. */ 373 LIST_REMOVE(p, p_hash); 374 simple_unlock(&deadproc_slock); 375 KERNEL_PROC_LOCK(curproc); 376 377 /* 378 * Give machine-dependent code a chance to free any 379 * resources it couldn't free while still running on 380 * that process's context. This must be done before 381 * uvm_exit(), in case these resources are in the PCB. 382 */ 383 cpu_wait(p); 384 385 /* 386 * Free the VM resources we're still holding on to. 387 * We must do this from a valid thread because doing 388 * so may block. 389 */ 390 uvm_exit(p); 391 392 /* Process is now a true zombie. */ 393 p->p_stat = SZOMB; 394 395 /* Wake up the parent so it can get exit status. */ 396 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 397 psignal(p->p_pptr, P_EXITSIG(p)); 398 KERNEL_PROC_UNLOCK(curproc); 399 wakeup((caddr_t)p->p_pptr); 400 } 401 } 402 403 int 404 sys_wait4(struct proc *q, void *v, register_t *retval) 405 { 406 struct sys_wait4_args /* { 407 syscallarg(int) pid; 408 syscallarg(int *) status; 409 syscallarg(int) options; 410 syscallarg(struct rusage *) rusage; 411 } */ *uap = v; 412 struct proc *p, *t; 413 int nfound, status, error, s; 414 415 if (SCARG(uap, pid) == 0) 416 SCARG(uap, pid) = -q->p_pgid; 417 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG)) 418 return (EINVAL); 419 420 loop: 421 nfound = 0; 422 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 423 if (SCARG(uap, pid) != WAIT_ANY && 424 p->p_pid != SCARG(uap, pid) && 425 p->p_pgid != -SCARG(uap, pid)) 426 continue; 427 /* 428 * Wait for processes with p_exitsig != SIGCHLD processes only 429 * if WALTSIG is set; wait for processes with p_exitsig == 430 * SIGCHLD only if WALTSIG is clear. 431 */ 432 if (((SCARG(uap, options) & WALLSIG) == 0) && 433 ((SCARG(uap, options) & WALTSIG) ? 434 (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD))) 435 continue; 436 437 nfound++; 438 if (p->p_stat == SZOMB) { 439 retval[0] = p->p_pid; 440 441 if (SCARG(uap, status)) { 442 status = p->p_xstat; /* convert to int */ 443 error = copyout((caddr_t)&status, 444 (caddr_t)SCARG(uap, status), 445 sizeof(status)); 446 if (error) 447 return (error); 448 } 449 if (SCARG(uap, rusage) && 450 (error = copyout((caddr_t)p->p_ru, 451 (caddr_t)SCARG(uap, rusage), 452 sizeof(struct rusage)))) 453 return (error); 454 /* 455 * If we got the child via ptrace(2) or procfs, and 456 * the parent is different (meaning the process was 457 * attached, rather than run as a child), then we need 458 * to give it back to the old parent, and send the 459 * parent the exit signal. The rest of the cleanup 460 * will be done when the old parent waits on the child. 461 */ 462 if ((p->p_flag & P_TRACED) && 463 p->p_oppid != p->p_pptr->p_pid) { 464 t = pfind(p->p_oppid); 465 proc_reparent(p, t ? t : initproc); 466 p->p_oppid = 0; 467 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 468 if (p->p_exitsig != 0) 469 psignal(p->p_pptr, P_EXITSIG(p)); 470 wakeup((caddr_t)p->p_pptr); 471 return (0); 472 } 473 scheduler_wait_hook(q, p); 474 p->p_xstat = 0; 475 ruadd(&q->p_stats->p_cru, p->p_ru); 476 pool_put(&rusage_pool, p->p_ru); 477 478 /* 479 * Finally finished with old proc entry. 480 * Unlink it from its process group and free it. 481 */ 482 leavepgrp(p); 483 484 s = proclist_lock_write(); 485 LIST_REMOVE(p, p_list); /* off zombproc */ 486 proclist_unlock_write(s); 487 488 LIST_REMOVE(p, p_sibling); 489 490 /* 491 * Decrement the count of procs running with this uid. 492 */ 493 (void)chgproccnt(p->p_cred->p_ruid, -1); 494 495 /* 496 * Free up credentials. 497 */ 498 if (--p->p_cred->p_refcnt == 0) { 499 crfree(p->p_cred->pc_ucred); 500 pool_put(&pcred_pool, p->p_cred); 501 } 502 503 /* 504 * Release reference to text vnode 505 */ 506 if (p->p_textvp) 507 vrele(p->p_textvp); 508 509 pool_put(&proc_pool, p); 510 nprocs--; 511 return (0); 512 } 513 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 514 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 515 p->p_flag |= P_WAITED; 516 retval[0] = p->p_pid; 517 518 if (SCARG(uap, status)) { 519 status = W_STOPCODE(p->p_xstat); 520 error = copyout((caddr_t)&status, 521 (caddr_t)SCARG(uap, status), 522 sizeof(status)); 523 } else 524 error = 0; 525 return (error); 526 } 527 } 528 if (nfound == 0) 529 return (ECHILD); 530 if (SCARG(uap, options) & WNOHANG) { 531 retval[0] = 0; 532 return (0); 533 } 534 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 535 return (error); 536 goto loop; 537 } 538 539 /* 540 * make process 'parent' the new parent of process 'child'. 541 */ 542 void 543 proc_reparent(struct proc *child, struct proc *parent) 544 { 545 546 if (child->p_pptr == parent) 547 return; 548 549 if (parent == initproc) 550 child->p_exitsig = SIGCHLD; 551 552 LIST_REMOVE(child, p_sibling); 553 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 554 child->p_pptr = parent; 555 } 556