Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exit.c
Version:
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1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 39 * $FreeBSD: src/sys/kern/kern_exit.c,v 1.41.2.2 1999/09/05 08:14:53 peter Exp $ 40 */ 41 42 #include "opt_ktrace.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/sysproto.h> 47 #include <sys/sysent.h> 48 #include <sys/ioctl.h> 49 #include <sys/proc.h> 50 #include <sys/tty.h> 51 #include <sys/time.h> 52 #include <sys/resource.h> 53 #include <sys/kernel.h> 54 #include <sys/buf.h> 55 #include <sys/wait.h> 56 #include <sys/file.h> 57 #include <sys/vnode.h> 58 #include <sys/syslog.h> 59 #include <sys/malloc.h> 60 #include <sys/resourcevar.h> 61 #include <sys/signalvar.h> 62 #include <sys/ptrace.h> 63 #include <sys/acct.h> /* for acct_process() function prototype */ 64 #include <sys/filedesc.h> 65 #include <sys/shm.h> 66 #include <sys/sem.h> 67 68 #ifdef COMPAT_43 69 #include <machine/reg.h> 70 #include <machine/psl.h> 71 #endif 72 73 #include <vm/vm.h> 74 #include <vm/vm_param.h> 75 #include <vm/vm_prot.h> 76 #include <vm/lock.h> 77 #include <vm/pmap.h> 78 #include <vm/vm_map.h> 79 #include <vm/vm_kern.h> 80 81 static int wait1 __P((struct proc *, struct wait_args *, int [], int)); 82 83 /* 84 * callout list for things to do at exit time 85 */ 86 typedef struct exit_list_element { 87 struct exit_list_element *next; 88 exitlist_fn function; 89 } *ele_p; 90 91 static ele_p exit_list; 92 93 /* 94 * exit -- 95 * Death of process. 96 */ 97 void 98 exit(p, uap, retval) 99 struct proc *p; 100 struct rexit_args /* { 101 int rval; 102 } */ *uap; 103 int *retval; 104 { 105 106 exit1(p, W_EXITCODE(uap->rval, 0)); 107 /* NOTREACHED */ 108 } 109 110 /* 111 * Exit: deallocate address space and other resources, change proc state 112 * to zombie, and unlink proc from allproc and parent's lists. Save exit 113 * status and rusage for wait(). Check for child processes and orphan them. 114 */ 115 void 116 exit1(p, rv) 117 register struct proc *p; 118 int rv; 119 { 120 register struct proc *q, *nq; 121 register struct vmspace *vm; 122 ele_p ep = exit_list; 123 124 if (p->p_pid == 1) { 125 printf("init died (signal %d, exit %d)\n", 126 WTERMSIG(rv), WEXITSTATUS(rv)); 127 panic("Going nowhere without my init!"); 128 } 129 #ifdef PGINPROF 130 vmsizmon(); 131 #endif 132 /* 133 * Check if any LKMs need anything done at process exit. 134 * e.g. SYSV IPC stuff 135 * XXX what if one of these generates an error? 136 */ 137 while (ep) { 138 (*ep->function)(p); 139 ep = ep->next; 140 } 141 142 if (p->p_flag & P_PROFIL) 143 stopprofclock(p); 144 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), 145 M_ZOMBIE, M_WAITOK); 146 /* 147 * If parent is waiting for us to exit or exec, 148 * P_PPWAIT is set; we will wakeup the parent below. 149 */ 150 p->p_flag &= ~(P_TRACED | P_PPWAIT); 151 p->p_flag |= P_WEXIT; 152 p->p_sigignore = ~0; 153 p->p_siglist = 0; 154 untimeout(realitexpire, (caddr_t)p); 155 156 /* 157 * Close open files and release open-file table. 158 * This may block! 159 */ 160 fdfree(p); 161 162 /* 163 * Delete select() buffers 164 */ 165 if (p->p_selbits) 166 free (p->p_selbits, M_SELECT); 167 168 /* 169 * XXX Shutdown SYSV semaphores 170 */ 171 semexit(p); 172 173 /* The next two chunks should probably be moved to vmspace_exit. */ 174 vm = p->p_vmspace; 175 if (vm->vm_shm) 176 shmexit(p); 177 /* 178 * Release user portion of address space. 179 * This releases references to vnodes, 180 * which could cause I/O if the file has been unlinked. 181 * Need to do this early enough that we can still sleep. 182 * Can't free the entire vmspace as the kernel stack 183 * may be mapped within that space also. 184 */ 185 if (vm->vm_refcnt == 1) { 186 pmap_remove_pages(&vm->vm_pmap, VM_MIN_ADDRESS, 187 VM_MAXUSER_ADDRESS); 188 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS, 189 VM_MAXUSER_ADDRESS); 190 } 191 192 if (SESS_LEADER(p)) { 193 register struct session *sp = p->p_session; 194 195 if (sp->s_ttyvp) { 196 /* 197 * Controlling process. 198 * Signal foreground pgrp, 199 * drain controlling terminal 200 * and revoke access to controlling terminal. 201 */ 202 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { 203 if (sp->s_ttyp->t_pgrp) 204 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); 205 (void) ttywait(sp->s_ttyp); 206 /* 207 * The tty could have been revoked 208 * if we blocked. 209 */ 210 if (sp->s_ttyvp) 211 vgoneall(sp->s_ttyvp); 212 } 213 if (sp->s_ttyvp) 214 vrele(sp->s_ttyvp); 215 sp->s_ttyvp = NULL; 216 /* 217 * s_ttyp is not zero'd; we use this to indicate 218 * that the session once had a controlling terminal. 219 * (for logging and informational purposes) 220 */ 221 } 222 sp->s_leader = NULL; 223 } 224 fixjobc(p, p->p_pgrp, 0); 225 if (p->p_limit->p_refcnt > 1 && 226 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) { 227 p->p_limit->p_refcnt--; 228 p->p_limit = limcopy(p->p_limit); 229 } 230 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 231 (void)acct_process(p); 232 #ifdef KTRACE 233 /* 234 * release trace file 235 */ 236 p->p_traceflag = 0; /* don't trace the vrele() */ 237 if (p->p_tracep) 238 vrele(p->p_tracep); 239 #endif 240 /* 241 * Remove proc from allproc queue and pidhash chain. 242 * Place onto zombproc. Unlink from parent's child list. 243 */ 244 LIST_REMOVE(p, p_list); 245 LIST_INSERT_HEAD(&zombproc, p, p_list); 246 p->p_stat = SZOMB; 247 248 LIST_REMOVE(p, p_hash); 249 250 q = p->p_children.lh_first; 251 if (q) /* only need this if any child is S_ZOMB */ 252 wakeup((caddr_t) initproc); 253 for (; q != 0; q = nq) { 254 nq = q->p_sibling.le_next; 255 LIST_REMOVE(q, p_sibling); 256 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling); 257 q->p_pptr = initproc; 258 /* 259 * Traced processes are killed 260 * since their existence means someone is screwing up. 261 */ 262 if (q->p_flag & P_TRACED) { 263 q->p_flag &= ~P_TRACED; 264 psignal(q, SIGKILL); 265 } 266 } 267 268 /* 269 * Save exit status and final rusage info, adding in child rusage 270 * info and self times. 271 */ 272 p->p_xstat = rv; 273 *p->p_ru = p->p_stats->p_ru; 274 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); 275 ruadd(p->p_ru, &p->p_stats->p_cru); 276 277 /* 278 * Notify parent that we're gone. 279 */ 280 psignal(p->p_pptr, SIGCHLD); 281 wakeup((caddr_t)p->p_pptr); 282 #if defined(tahoe) 283 /* move this to cpu_exit */ 284 p->p_addr->u_pcb.pcb_savacc.faddr = (float *)NULL; 285 #endif 286 /* 287 * Clear curproc after we've done all operations 288 * that could block, and before tearing down the rest 289 * of the process state that might be used from clock, etc. 290 * Also, can't clear curproc while we're still runnable, 291 * as we're not on a run queue (we are current, just not 292 * a proper proc any longer!). 293 * 294 * Other substructures are freed from wait(). 295 */ 296 curproc = NULL; 297 if (--p->p_limit->p_refcnt == 0) { 298 FREE(p->p_limit, M_SUBPROC); 299 p->p_limit = NULL; 300 } 301 302 /* 303 * Finally, call machine-dependent code to release the remaining 304 * resources including address space, the kernel stack and pcb. 305 * The address space is released by "vmspace_free(p->p_vmspace)"; 306 * This is machine-dependent, as we may have to change stacks 307 * or ensure that the current one isn't reallocated before we 308 * finish. cpu_exit will end with a call to cpu_switch(), finishing 309 * our execution (pun intended). 310 */ 311 cpu_exit(p); 312 } 313 314 #ifdef COMPAT_43 315 #if defined(hp300) || defined(luna68k) 316 #include <machine/frame.h> 317 #define GETPS(rp) ((struct frame *)(rp))->f_sr 318 #else 319 #define GETPS(rp) (rp)[PS] 320 #endif 321 322 int 323 owait(p, uap, retval) 324 struct proc *p; 325 register struct owait_args /* { 326 int dummy; 327 } */ *uap; 328 int *retval; 329 { 330 struct wait_args w; 331 332 #ifdef PSL_ALLCC 333 if ((GETPS(p->p_md.md_regs) & PSL_ALLCC) != PSL_ALLCC) { 334 w.options = 0; 335 w.rusage = NULL; 336 } else { 337 w.options = p->p_md.md_regs[R0]; 338 w.rusage = (struct rusage *)p->p_md.md_regs[R1]; 339 } 340 #else 341 w.options = 0; 342 w.rusage = NULL; 343 #endif 344 w.pid = WAIT_ANY; 345 w.status = NULL; 346 return (wait1(p, &w, retval, 1)); 347 } 348 #endif /* COMPAT_43 */ 349 350 int 351 wait4(p, uap, retval) 352 struct proc *p; 353 struct wait_args *uap; 354 int *retval; 355 { 356 357 return (wait1(p, uap, retval, 0)); 358 } 359 360 static int 361 wait1(q, uap, retval, compat) 362 register struct proc *q; 363 register struct wait_args /* { 364 int pid; 365 int *status; 366 int options; 367 struct rusage *rusage; 368 } */ *uap; 369 int retval[]; 370 int compat; 371 { 372 register int nfound; 373 register struct proc *p, *t; 374 int status, error; 375 376 if (uap->pid == 0) 377 uap->pid = -q->p_pgid; 378 #ifdef notyet 379 if (uap->options &~ (WUNTRACED|WNOHANG)) 380 return (EINVAL); 381 #endif 382 loop: 383 nfound = 0; 384 for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { 385 if (uap->pid != WAIT_ANY && 386 p->p_pid != uap->pid && p->p_pgid != -uap->pid) 387 continue; 388 nfound++; 389 if (p->p_stat == SZOMB) { 390 /* charge childs scheduling cpu usage to parent */ 391 if (curproc->p_pid != 1) { 392 curproc->p_estcpu = min(curproc->p_estcpu + 393 p->p_estcpu, UCHAR_MAX); 394 } 395 396 retval[0] = p->p_pid; 397 #ifdef COMPAT_43 398 if (compat) 399 retval[1] = p->p_xstat; 400 else 401 #endif 402 if (uap->status) { 403 status = p->p_xstat; /* convert to int */ 404 if ((error = copyout((caddr_t)&status, 405 (caddr_t)uap->status, sizeof(status)))) 406 return (error); 407 } 408 if (uap->rusage && (error = copyout((caddr_t)p->p_ru, 409 (caddr_t)uap->rusage, sizeof (struct rusage)))) 410 return (error); 411 /* 412 * If we got the child via a ptrace 'attach', 413 * we need to give it back to the old parent. 414 */ 415 if (p->p_oppid && (t = pfind(p->p_oppid))) { 416 p->p_oppid = 0; 417 proc_reparent(p, t); 418 psignal(t, SIGCHLD); 419 wakeup((caddr_t)t); 420 return (0); 421 } 422 p->p_xstat = 0; 423 ruadd(&q->p_stats->p_cru, p->p_ru); 424 FREE(p->p_ru, M_ZOMBIE); 425 p->p_ru = NULL; 426 427 /* 428 * Decrement the count of procs running with this uid. 429 */ 430 (void)chgproccnt(p->p_cred->p_ruid, -1); 431 432 /* 433 * Release reference to text vnode 434 */ 435 if (p->p_textvp) 436 vrele(p->p_textvp); 437 438 /* 439 * Free up credentials. 440 */ 441 if (--p->p_cred->p_refcnt == 0) { 442 crfree(p->p_cred->pc_ucred); 443 FREE(p->p_cred, M_SUBPROC); 444 p->p_cred = NULL; 445 } 446 447 /* 448 * Finally finished with old proc entry. 449 * Unlink it from its process group and free it. 450 */ 451 leavepgrp(p); 452 LIST_REMOVE(p, p_list); /* off zombproc */ 453 LIST_REMOVE(p, p_sibling); 454 455 /* 456 * Give machine-dependent layer a chance 457 * to free anything that cpu_exit couldn't 458 * release while still running in process context. 459 */ 460 cpu_wait(p); 461 FREE(p, M_PROC); 462 nprocs--; 463 return (0); 464 } 465 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && 466 (p->p_flag & P_TRACED || uap->options & WUNTRACED)) { 467 p->p_flag |= P_WAITED; 468 retval[0] = p->p_pid; 469 #ifdef COMPAT_43 470 if (compat) { 471 retval[1] = W_STOPCODE(p->p_xstat); 472 error = 0; 473 } else 474 #endif 475 if (uap->status) { 476 status = W_STOPCODE(p->p_xstat); 477 error = copyout((caddr_t)&status, 478 (caddr_t)uap->status, sizeof(status)); 479 } else 480 error = 0; 481 return (error); 482 } 483 } 484 if (nfound == 0) 485 return (ECHILD); 486 if (uap->options & WNOHANG) { 487 retval[0] = 0; 488 return (0); 489 } 490 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0))) 491 return (error); 492 goto loop; 493 } 494 495 /* 496 * make process 'parent' the new parent of process 'child'. 497 */ 498 void 499 proc_reparent(child, parent) 500 register struct proc *child; 501 register struct proc *parent; 502 { 503 504 if (child->p_pptr == parent) 505 return; 506 507 LIST_REMOVE(child, p_sibling); 508 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); 509 child->p_pptr = parent; 510 } 511 512 /* 513 * The next two functions are to handle adding/deleting items on the 514 * exit callout list 515 * 516 * at_exit(): 517 * Take the arguments given and put them onto the exit callout list, 518 * However first make sure that it's not already there. 519 * returns 0 on success. 520 */ 521 int 522 at_exit(exitlist_fn function) 523 { 524 ele_p ep; 525 526 /* Be noisy if the programmer has lost track of things */ 527 if (rm_at_exit(function)) 528 printf("exit callout entry already present\n"); 529 ep = malloc(sizeof(*ep), M_TEMP, M_NOWAIT); 530 if (ep == NULL) 531 return (ENOMEM); 532 ep->next = exit_list; 533 ep->function = function; 534 exit_list = ep; 535 return (0); 536 } 537 /* 538 * Scan the exit callout list for the given items and remove them. 539 * Returns the number of items removed. 540 * Logically this can only be 0 or 1. 541 */ 542 int 543 rm_at_exit(exitlist_fn function) 544 { 545 ele_p *epp, ep; 546 int count; 547 548 count = 0; 549 epp = &exit_list; 550 ep = *epp; 551 while (ep) { 552 if (ep->function == function) { 553 *epp = ep->next; 554 free(ep, M_TEMP); 555 count++; 556 } else { 557 epp = &ep->next; 558 } 559 ep = *epp; 560 } 561 return (count); 562 } 563 564
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