1 /* $NetBSD: kern_exit.c,v 1.87 2000/12/22 22:59:00 jdolecek 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 "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 <uvm/uvm_extern.h> 120 121 /* 122 * exit -- 123 * Death of process. 124 */ 125 int 126 sys_exit(struct proc *p, void *v, register_t *retval) 127 { 128 struct sys_exit_args /* { 129 syscallarg(int) rval; 130 } */ *uap = v; 131 132 exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); 133 /* NOTREACHED */ 134 return (0); 135 } 136 137 /* 138 * Exit: deallocate address space and other resources, change proc state 139 * to zombie, and unlink proc from allproc and parent's lists. Save exit 140 * status and rusage for wait(). Check for child processes and orphan them. 141 */ 142 void 143 exit1(struct proc *p, int rv) 144 { 145 struct proc *q, *nq; 146 struct vmspace *vm; 147 int s; 148 149 if (__predict_false(p == initproc)) 150 panic("init died (signal %d, exit %d)", 151 WTERMSIG(rv), WEXITSTATUS(rv)); 152 153 #ifdef PGINPROF 154 vmsizmon(); 155 #endif 156 if (p->p_flag & P_PROFIL) 157 stopprofclock(p); 158 p->p_ru = pool_get(&rusage_pool, PR_WAITOK); 159 /* 160 * If parent is waiting for us to exit or exec, P_PPWAIT is set; we 161 * wake up the parent early to avoid deadlock. 162 */ 163 p->p_flag |= P_WEXIT; 164 if (p->p_flag & P_PPWAIT) { 165 p->p_flag &= ~P_PPWAIT; 166 wakeup((caddr_t)p->p_pptr); 167 } 168 sigfillset(&p->p_sigctx.ps_sigignore); 169 sigemptyset(&p->p_sigctx.ps_siglist); 170 p->p_sigctx.ps_sigcheck = 0; 171 callout_stop(&p->p_realit_ch); 172 173 /* 174 * Close open files and release open-file table. 175 * This may block! 176 */ 177 fdfree(p); 178 cwdfree(p); 179 180 /* The next three chunks should probably be moved to vmspace_exit. */ 181 vm = p->p_vmspace; 182 #ifdef SYSVSHM 183 if (vm->vm_shm && vm->vm_refcnt == 1) 184 shmexit(vm); 185 #endif 186 #ifdef SYSVSEM 187 semexit(p); 188 #endif 189 /* 190 * Release user portion of address space. 191 * This releases references to vnodes, 192 * which could cause I/O if the file has been unlinked. 193 * Need to do this early enough that we can still sleep. 194 * Can't free the entire vmspace as the kernel stack 195 * may be mapped within that space also. 196 */ 197 if (vm->vm_refcnt == 1) 198 (void) uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 199 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 200 201 if (SESS_LEADER(p)) { 202 struct session *sp = p->p_session; 203 204 if (sp->s_ttyvp) { 205 /* 206 * Controlling process. 207 * Signal foreground pgrp, 208 * drain controlling terminal 209 * and revoke access to controlling terminal. 210 */ 211 if (sp->s_ttyp->t_session == sp) { 212 if (sp->s_ttyp->t_pgrp) 213 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 214 (void) ttywait(sp->s_ttyp); 215 /* 216 * The tty could have been revoked 217 * if we blocked. 218 */ 219 if (sp->s_ttyvp) 220 VOP_REVOKE(sp->s_ttyvp, REVOKEALL); 221 } 222 if (sp->s_ttyvp) 223 vrele(sp->s_ttyvp); 224 sp->s_ttyvp = NULL; 225 /* 226 * s_ttyp is not zero'd; we use this to indicate 227 * that the session once had a controlling terminal. 228 * (for logging and informational purposes) 229 */ 230 } 231 sp->s_leader = NULL; 232 } 233 fixjobc(p, p->p_pgrp, 0); 234 (void)acct_process(p); 235 #ifdef KTRACE 236 /* 237 * release trace file 238 */ 239 ktrderef(p); 240 #endif 241 /* 242 * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! 243 */ 244 p->p_stat = SDEAD; 245 246 /* 247 * Remove proc from pidhash chain so looking it up won't 248 * work. Move it from allproc to zombproc, but do not yet 249 * wake up the reaper. We will put the proc on the 250 * deadproc list later (using the p_hash member), and 251 * wake up the reaper when we do. 252 */ 253 s = proclist_lock_write(); 254 LIST_REMOVE(p, p_hash); 255 LIST_REMOVE(p, p_list); 256 LIST_INSERT_HEAD(&zombproc, p, p_list); 257 proclist_unlock_write(s); 258 259 /* 260 * Give orphaned children to init(8). 261 */ 262 q = p->p_children.lh_first; 263 if (q) /* only need this if any child is S_ZOMB */ 264 wakeup((caddr_t)initproc); 265 for (; q != 0; q = nq) { 266 nq = q->p_sibling.le_next; 267 proc_reparent(q, initproc); 268 /* 269 * Traced processes are killed 270 * since their existence means someone is screwing up. 271 */ 272 if (q->p_flag & P_TRACED) { 273 q->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 274 psignal(q, SIGKILL); 275 } 276 } 277 278 /* 279 * Save exit status and final rusage info, adding in child rusage 280 * info and self times. 281 */ 282 p->p_xstat = rv; 283 *p->p_ru = p->p_stats->p_ru; 284 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 285 ruadd(p->p_ru, &p->p_stats->p_cru); 286 287 /* 288 * Notify parent that we're gone. If parent has the P_NOCLDWAIT 289 * flag set, notify init instead (and hope it will handle 290 * this situation). 291 */ 292 if (p->p_pptr->p_flag & P_NOCLDWAIT) { 293 struct proc *pp = p->p_pptr; 294 proc_reparent(p, initproc); 295 /* 296 * If this was the last child of our parent, notify 297 * parent, so in case he was wait(2)ing, he will 298 * continue. 299 */ 300 if (pp->p_children.lh_first == NULL) 301 wakeup((caddr_t)pp); 302 } 303 304 /* 305 * Release the process's signal state. 306 */ 307 sigactsfree(p); 308 309 /* 310 * Clear curproc after we've done all operations 311 * that could block, and before tearing down the rest 312 * of the process state that might be used from clock, etc. 313 * Also, can't clear curproc while we're still runnable, 314 * as we're not on a run queue (we are current, just not 315 * a proper proc any longer!). 316 * 317 * Other substructures are freed from wait(). 318 */ 319 curproc = NULL; 320 limfree(p->p_limit); 321 p->p_limit = NULL; 322 323 /* 324 * If emulation has process exit hook, call it now. 325 */ 326 if (p->p_emul->e_proc_exit) 327 (*p->p_emul->e_proc_exit)(p); 328 329 /* This process no longer needs to hold the kernel lock. */ 330 KERNEL_PROC_UNLOCK(p); 331 332 /* 333 * Finally, call machine-dependent code to switch to a new 334 * context (possibly the idle context). Once we are no longer 335 * using the dead process's vmspace and stack, exit2() will be 336 * called to schedule those resources to be released by the 337 * reaper thread. 338 * 339 * Note that cpu_exit() will end with a call equivalent to 340 * cpu_switch(), finishing our execution (pun intended). 341 */ 342 cpu_exit(p); 343 } 344 345 /* 346 * We are called from cpu_exit() once it is safe to schedule the 347 * dead process's resources to be freed (i.e., once we've switched to 348 * the idle PCB for the current CPU). 349 * 350 * NOTE: One must be careful with locking in this routine. It's 351 * called from a critical section in machine-dependent code, so 352 * we should refrain from changing any interrupt state. 353 * 354 * We lock the deadproc list (a spin lock), place the proc on that 355 * list (using the p_hash member), and wake up the reaper. 356 */ 357 void 358 exit2(struct proc *p) 359 { 360 361 simple_lock(&deadproc_slock); 362 LIST_INSERT_HEAD(&deadproc, p, p_hash); 363 simple_unlock(&deadproc_slock); 364 365 wakeup(&deadproc); 366 } 367 368 /* 369 * Process reaper. This is run by a kernel thread to free the resources 370 * of a dead process. Once the resources are free, the process becomes 371 * a zombie, and the parent is allowed to read the undead's status. 372 */ 373 void 374 reaper(void *arg) 375 { 376 struct proc *p; 377 378 for (;;) { 379 simple_lock(&deadproc_slock); 380 p = LIST_FIRST(&deadproc); 381 if (p == NULL) { 382 /* No work for us; go to sleep until someone exits. */ 383 (void) ltsleep(&deadproc, PVM|PNORELOCK, 384 "reaper", 0, &deadproc_slock); 385 continue; 386 } 387 388 /* Remove us from the deadproc list. */ 389 LIST_REMOVE(p, p_hash); 390 simple_unlock(&deadproc_slock); 391 392 /* 393 * Give machine-dependent code a chance to free any 394 * resources it couldn't free while still running on 395 * that process's context. This must be done before 396 * uvm_exit(), in case these resources are in the PCB. 397 */ 398 cpu_wait(p); 399 400 /* 401 * Free the VM resources we're still holding on to. 402 * We must do this from a valid thread because doing 403 * so may block. 404 */ 405 uvm_exit(p); 406 407 /* Process is now a true zombie. */ 408 p->p_stat = SZOMB; 409 410 /* Wake up the parent so it can get exit status. */ 411 if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) 412 psignal(p->p_pptr, P_EXITSIG(p)); 413 wakeup((caddr_t)p->p_pptr); 414 } 415 } 416 417 int 418 sys_wait4(struct proc *q, void *v, register_t *retval) 419 { 420 struct sys_wait4_args /* { 421 syscallarg(int) pid; 422 syscallarg(int *) status; 423 syscallarg(int) options; 424 syscallarg(struct rusage *) rusage; 425 } */ *uap = v; 426 int nfound; 427 struct proc *p, *t; 428 int status, error, s; 429 430 if (SCARG(uap, pid) == 0) 431 SCARG(uap, pid) = -q->p_pgid; 432 if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG)) 433 return (EINVAL); 434 435 loop: 436 nfound = 0; 437 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 438 if (SCARG(uap, pid) != WAIT_ANY && 439 p->p_pid != SCARG(uap, pid) && 440 p->p_pgid != -SCARG(uap, pid)) 441 continue; 442 /* 443 * Wait for processes with p_exitsig != SIGCHLD processes only 444 * if WALTSIG is set; wait for processes with p_exitsig == 445 * SIGCHLD only if WALTSIG is clear. 446 */ 447 if ((SCARG(uap, options) & WALTSIG) ? 448 (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD)) 449 continue; 450 451 nfound++; 452 if (p->p_stat == SZOMB) { 453 retval[0] = p->p_pid; 454 455 if (SCARG(uap, status)) { 456 status = p->p_xstat; /* convert to int */ 457 error = copyout((caddr_t)&status, 458 (caddr_t)SCARG(uap, status), 459 sizeof(status)); 460 if (error) 461 return (error); 462 } 463 if (SCARG(uap, rusage) && 464 (error = copyout((caddr_t)p->p_ru, 465 (caddr_t)SCARG(uap, rusage), 466 sizeof(struct rusage)))) 467 return (error); 468 /* 469 * If we got the child via ptrace(2) or procfs, and 470 * the parent is different (meaning the process was 471 * attached, rather than run as a child), then we need 472 * to give it back to the old parent, and send the 473 * parent the exit signal. The rest of the cleanup 474 * will be done when the old parent waits on the child. 475 */ 476 if ((p->p_flag & P_TRACED) && 477 p->p_oppid != p->p_pptr->p_pid) { 478 t = pfind(p->p_oppid); 479 proc_reparent(p, t ? t : initproc); 480 p->p_oppid = 0; 481 p->p_flag &= ~(P_TRACED|P_WAITED|P_FSTRACE); 482 if (p->p_exitsig != 0) 483 psignal(p->p_pptr, P_EXITSIG(p)); 484 wakeup((caddr_t)p->p_pptr); 485 return (0); 486 } 487 scheduler_wait_hook(q, p); 488 p->p_xstat = 0; 489 ruadd(&q->p_stats->p_cru, p->p_ru); 490 pool_put(&rusage_pool, p->p_ru); 491 492 /* 493 * Finally finished with old proc entry. 494 * Unlink it from its process group and free it. 495 */ 496 leavepgrp(p); 497 498 s = proclist_lock_write(); 499 LIST_REMOVE(p, p_list); /* off zombproc */ 500 proclist_unlock_write(s); 501 502 LIST_REMOVE(p, p_sibling); 503 504 /* 505 * Decrement the count of procs running with this uid. 506 */ 507 (void)chgproccnt(p->p_cred->p_ruid, -1); 508 509 /* 510 * Free up credentials. 511 */ 512 if (--p->p_cred->p_refcnt == 0) { 513 crfree(p->p_cred->pc_ucred); 514 pool_put(&pcred_pool, p->p_cred); 515 } 516 517 /* 518 * Release reference to text vnode 519 */ 520 if (p->p_textvp) 521 vrele(p->p_textvp); 522 523 pool_put(&proc_pool, p); 524 nprocs--; 525 return (0); 526 } 527 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 528 (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { 529 p->p_flag |= P_WAITED; 530 retval[0] = p->p_pid; 531 532 if (SCARG(uap, status)) { 533 status = W_STOPCODE(p->p_xstat); 534 error = copyout((caddr_t)&status, 535 (caddr_t)SCARG(uap, status), 536 sizeof(status)); 537 } else 538 error = 0; 539 return (error); 540 } 541 } 542 if (nfound == 0) 543 return (ECHILD); 544 if (SCARG(uap, options) & WNOHANG) { 545 retval[0] = 0; 546 return (0); 547 } 548 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) 549 return (error); 550 goto loop; 551 } 552 553 /* 554 * make process 'parent' the new parent of process 'child'. 555 */ 556 void 557 proc_reparent(struct proc *child, struct proc *parent) 558 { 559 560 if (child->p_pptr == parent) 561 return; 562 563 if (parent == initproc) 564 child->p_exitsig = SIGCHLD; 565 566 LIST_REMOVE(child, p_sibling); 567 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 568 child->p_pptr = parent; 569 } 570