1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * Copyright (c) 2005 Robert N. M. Watson 8 * All rights reserved. 9 * 10 * All or some portions of this file are derived from material licensed 11 * to the University of California by American Telephone and Telegraph 12 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 13 * the permission of UNIX System Laboratories, Inc. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * Copyright (c) 1994 Christopher G. Demetriou 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 3. All advertising materials mentioning features or use of this software 50 * must display the following acknowledgement: 51 * This product includes software developed by the University of 52 * California, Berkeley and its contributors. 53 * 4. Neither the name of the University nor the names of its contributors 54 * may be used to endorse or promote products derived from this software 55 * without specific prior written permission. 56 * 57 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 58 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 59 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 60 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 61 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 62 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 63 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 64 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 65 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 66 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 67 * SUCH DAMAGE. 68 * 69 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 70 */ 71 72 #include <sys/cdefs.h> 73 __FBSDID("$FreeBSD$"); 74 75 #include <sys/param.h> 76 #include <sys/systm.h> 77 #include <sys/acct.h> 78 #include <sys/fcntl.h> 79 #include <sys/kernel.h> 80 #include <sys/kthread.h> 81 #include <sys/limits.h> 82 #include <sys/lock.h> 83 #include <sys/malloc.h> 84 #include <sys/mount.h> 85 #include <sys/mutex.h> 86 #include <sys/namei.h> 87 #include <sys/priv.h> 88 #include <sys/proc.h> 89 #include <sys/resourcevar.h> 90 #include <sys/sched.h> 91 #include <sys/sx.h> 92 #include <sys/sysctl.h> 93 #include <sys/syslog.h> 94 #include <sys/sysproto.h> 95 #include <sys/tty.h> 96 #include <sys/vnode.h> 97 98 #include <security/mac/mac_framework.h> 99 100 _Static_assert(sizeof(struct acctv3) - offsetof(struct acctv3, ac_trailer) == 101 sizeof(struct acctv2) - offsetof(struct acctv2, ac_trailer), "trailer"); 102 _Static_assert(sizeof(struct acctv3) - offsetof(struct acctv3, ac_len2) == 103 sizeof(struct acctv2) - offsetof(struct acctv2, ac_len2), "len2"); 104 105 /* 106 * The routines implemented in this file are described in: 107 * Leffler, et al.: The Design and Implementation of the 4.3BSD 108 * UNIX Operating System (Addison Welley, 1989) 109 * on pages 62-63. 110 * On May 2007 the historic 3 bits base 8 exponent, 13 bit fraction 111 * compt_t representation described in the above reference was replaced 112 * with that of IEEE-754 floats. 113 * 114 * Arguably, to simplify accounting operations, this mechanism should 115 * be replaced by one in which an accounting log file (similar to /dev/klog) 116 * is read by a user process, etc. However, that has its own problems. 117 */ 118 119 /* Floating point definitions from <float.h>. */ 120 #define FLT_MANT_DIG 24 /* p */ 121 #define FLT_MAX_EXP 128 /* emax */ 122 123 /* 124 * Internal accounting functions. 125 * The former's operation is described in Leffler, et al., and the latter 126 * was provided by UCB with the 4.4BSD-Lite release 127 */ 128 static uint32_t encode_timeval(struct timeval); 129 static uint32_t encode_long(long); 130 static void acctwatch(void); 131 static void acct_thread(void *); 132 static int acct_disable(struct thread *, int); 133 134 /* 135 * Accounting vnode pointer, saved vnode pointer, and flags for each. 136 * acct_sx protects against changes to the active vnode and credentials 137 * while accounting records are being committed to disk. 138 */ 139 static int acct_configured; 140 static int acct_suspended; 141 static struct vnode *acct_vp; 142 static struct ucred *acct_cred; 143 static int acct_flags; 144 static struct sx acct_sx; 145 146 SX_SYSINIT(acct, &acct_sx, "acct_sx"); 147 148 /* 149 * State of the accounting kthread. 150 */ 151 static int acct_state; 152 153 #define ACCT_RUNNING 1 /* Accounting kthread is running. */ 154 #define ACCT_EXITREQ 2 /* Accounting kthread should exit. */ 155 156 /* 157 * Values associated with enabling and disabling accounting 158 */ 159 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 160 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 161 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 162 163 static int acctresume = 4; /* resume when free space risen to > 4% */ 164 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 165 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 166 167 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 168 169 static int 170 sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS) 171 { 172 int error, value; 173 174 /* Write out the old value. */ 175 error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int)); 176 if (error || req->newptr == NULL) 177 return (error); 178 179 /* Read in and verify the new value. */ 180 error = SYSCTL_IN(req, &value, sizeof(int)); 181 if (error) 182 return (error); 183 if (value <= 0) 184 return (EINVAL); 185 acctchkfreq = value; 186 return (0); 187 } 188 SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq, 189 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, &acctchkfreq, 0, 190 sysctl_acct_chkfreq, "I", 191 "frequency for checking the free space"); 192 193 SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0, 194 "Accounting configured or not"); 195 196 SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0, 197 "Accounting suspended or not"); 198 199 /* 200 * Accounting system call. Written based on the specification and previous 201 * implementation done by Mark Tinguely. 202 */ 203 int 204 sys_acct(struct thread *td, struct acct_args *uap) 205 { 206 struct nameidata nd; 207 int error, flags, replacing; 208 209 error = priv_check(td, PRIV_ACCT); 210 if (error) 211 return (error); 212 213 /* 214 * If accounting is to be started to a file, open that file for 215 * appending and make sure it's a 'normal'. 216 */ 217 if (uap->path != NULL) { 218 NDINIT(&nd, LOOKUP, NOFOLLOW | AUDITVNODE1, UIO_USERSPACE, 219 uap->path); 220 flags = FWRITE | O_APPEND; 221 error = vn_open(&nd, &flags, 0, NULL); 222 if (error) 223 return (error); 224 NDFREE_PNBUF(&nd); 225 #ifdef MAC 226 error = mac_system_check_acct(td->td_ucred, nd.ni_vp); 227 if (error) { 228 VOP_UNLOCK(nd.ni_vp); 229 vn_close(nd.ni_vp, flags, td->td_ucred, td); 230 return (error); 231 } 232 #endif 233 VOP_UNLOCK(nd.ni_vp); 234 if (nd.ni_vp->v_type != VREG) { 235 vn_close(nd.ni_vp, flags, td->td_ucred, td); 236 return (EACCES); 237 } 238 #ifdef MAC 239 } else { 240 error = mac_system_check_acct(td->td_ucred, NULL); 241 if (error) 242 return (error); 243 #endif 244 } 245 246 /* 247 * Disallow concurrent access to the accounting vnode while we swap 248 * it out, in order to prevent access after close. 249 */ 250 sx_xlock(&acct_sx); 251 252 /* 253 * Don't log spurious disable/enable messages if we are 254 * switching from one accounting file to another due to log 255 * rotation. 256 */ 257 replacing = (acct_vp != NULL && uap->path != NULL); 258 259 /* 260 * If accounting was previously enabled, kill the old space-watcher, 261 * close the file, and (if no new file was specified, leave). Reset 262 * the suspended state regardless of whether accounting remains 263 * enabled. 264 */ 265 acct_suspended = 0; 266 if (acct_vp != NULL) 267 error = acct_disable(td, !replacing); 268 if (uap->path == NULL) { 269 if (acct_state & ACCT_RUNNING) { 270 acct_state |= ACCT_EXITREQ; 271 wakeup(&acct_state); 272 } 273 sx_xunlock(&acct_sx); 274 return (error); 275 } 276 277 /* 278 * Save the new accounting file vnode, and schedule the new 279 * free space watcher. 280 */ 281 acct_vp = nd.ni_vp; 282 acct_cred = crhold(td->td_ucred); 283 acct_flags = flags; 284 if (acct_state & ACCT_RUNNING) 285 acct_state &= ~ACCT_EXITREQ; 286 else { 287 /* 288 * Try to start up an accounting kthread. We may start more 289 * than one, but if so the extras will commit suicide as 290 * soon as they start up. 291 */ 292 error = kproc_create(acct_thread, NULL, NULL, 0, 0, 293 "accounting"); 294 if (error) { 295 (void) acct_disable(td, 0); 296 sx_xunlock(&acct_sx); 297 log(LOG_NOTICE, "Unable to start accounting thread\n"); 298 return (error); 299 } 300 } 301 acct_configured = 1; 302 sx_xunlock(&acct_sx); 303 if (!replacing) 304 log(LOG_NOTICE, "Accounting enabled\n"); 305 return (error); 306 } 307 308 /* 309 * Disable currently in-progress accounting by closing the vnode, dropping 310 * our reference to the credential, and clearing the vnode's flags. 311 */ 312 static int 313 acct_disable(struct thread *td, int logging) 314 { 315 int error; 316 317 sx_assert(&acct_sx, SX_XLOCKED); 318 error = vn_close(acct_vp, acct_flags, acct_cred, td); 319 crfree(acct_cred); 320 acct_configured = 0; 321 acct_vp = NULL; 322 acct_cred = NULL; 323 acct_flags = 0; 324 if (logging) 325 log(LOG_NOTICE, "Accounting disabled\n"); 326 return (error); 327 } 328 329 /* 330 * Write out process accounting information, on process exit. 331 * Data to be written out is specified in Leffler, et al. 332 * and are enumerated below. (They're also noted in the system 333 * "acct.h" header file.) 334 */ 335 int 336 acct_process(struct thread *td) 337 { 338 struct acctv3 acct; 339 struct timeval ut, st, tmp; 340 struct proc *p; 341 struct rusage ru; 342 int t, ret; 343 344 /* 345 * Lockless check of accounting condition before doing the hard 346 * work. 347 */ 348 if (acct_vp == NULL || acct_suspended) 349 return (0); 350 351 memset(&acct, 0, sizeof(acct)); 352 353 sx_slock(&acct_sx); 354 355 /* 356 * If accounting isn't enabled, don't bother. Have to check again 357 * once we own the lock in case we raced with disabling of accounting 358 * by another thread. 359 */ 360 if (acct_vp == NULL || acct_suspended) { 361 sx_sunlock(&acct_sx); 362 return (0); 363 } 364 365 p = td->td_proc; 366 td->td_pflags2 |= TDP2_ACCT; 367 368 /* 369 * Get process accounting information. 370 */ 371 372 sx_slock(&proctree_lock); 373 PROC_LOCK(p); 374 375 /* (1) The terminal from which the process was started */ 376 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 377 acct.ac_tty = tty_udev(p->p_pgrp->pg_session->s_ttyp); 378 else 379 acct.ac_tty = NODEV; 380 sx_sunlock(&proctree_lock); 381 382 /* (2) The name of the command that ran */ 383 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 384 385 /* (3) The amount of user and system time that was used */ 386 rufetchcalc(p, &ru, &ut, &st); 387 acct.ac_utime = encode_timeval(ut); 388 acct.ac_stime = encode_timeval(st); 389 390 /* (4) The elapsed time the command ran (and its starting time) */ 391 getboottime(&tmp); 392 timevaladd(&tmp, &p->p_stats->p_start); 393 acct.ac_btime = tmp.tv_sec; 394 microuptime(&tmp); 395 timevalsub(&tmp, &p->p_stats->p_start); 396 acct.ac_etime = encode_timeval(tmp); 397 398 /* (5) The average amount of memory used */ 399 tmp = ut; 400 timevaladd(&tmp, &st); 401 /* Convert tmp (i.e. u + s) into hz units to match ru_i*. */ 402 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 403 if (t) 404 acct.ac_mem = encode_long((ru.ru_ixrss + ru.ru_idrss + 405 + ru.ru_isrss) / t); 406 else 407 acct.ac_mem = 0; 408 409 /* (6) The number of disk I/O operations done */ 410 acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock); 411 412 /* (7) The UID and GID of the process */ 413 acct.ac_uid = p->p_ucred->cr_ruid; 414 acct.ac_gid = p->p_ucred->cr_rgid; 415 416 /* (8) The boolean flags that tell how the process terminated, etc. */ 417 acct.ac_flagx = p->p_acflag; 418 419 PROC_UNLOCK(p); 420 421 /* Setup ancillary structure fields. */ 422 acct.ac_flagx |= ANVER; 423 acct.ac_zero = 0; 424 acct.ac_version = 3; 425 acct.ac_len = acct.ac_len2 = sizeof(acct); 426 427 /* 428 * Write the accounting information to the file. 429 */ 430 ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct), 431 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED, 432 NULL, td); 433 sx_sunlock(&acct_sx); 434 td->td_pflags2 &= ~TDP2_ACCT; 435 return (ret); 436 } 437 438 /* FLOAT_CONVERSION_START (Regression testing; don't remove this line.) */ 439 440 /* Convert timevals and longs into IEEE-754 bit patterns. */ 441 442 /* Mantissa mask (MSB is implied, so subtract 1). */ 443 #define MANT_MASK ((1 << (FLT_MANT_DIG - 1)) - 1) 444 445 /* 446 * We calculate integer values to a precision of approximately 447 * 28 bits. 448 * This is high-enough precision to fill the 24 float bits 449 * and low-enough to avoid overflowing the 32 int bits. 450 */ 451 #define CALC_BITS 28 452 453 /* log_2(1000000). */ 454 #define LOG2_1M 20 455 456 /* 457 * Convert the elements of a timeval into a 32-bit word holding 458 * the bits of a IEEE-754 float. 459 * The float value represents the timeval's value in microsecond units. 460 */ 461 static uint32_t 462 encode_timeval(struct timeval tv) 463 { 464 int log2_s; 465 int val, exp; /* Unnormalized value and exponent */ 466 int norm_exp; /* Normalized exponent */ 467 int shift; 468 469 /* 470 * First calculate value and exponent to about CALC_BITS precision. 471 * Note that the following conditionals have been ordered so that 472 * the most common cases appear first. 473 */ 474 if (tv.tv_sec == 0) { 475 if (tv.tv_usec == 0) 476 return (0); 477 exp = 0; 478 val = tv.tv_usec; 479 } else { 480 /* 481 * Calculate the value to a precision of approximately 482 * CALC_BITS. 483 */ 484 log2_s = fls(tv.tv_sec) - 1; 485 if (log2_s + LOG2_1M < CALC_BITS) { 486 exp = 0; 487 val = 1000000 * tv.tv_sec + tv.tv_usec; 488 } else { 489 exp = log2_s + LOG2_1M - CALC_BITS; 490 val = (unsigned int)(((uint64_t)1000000 * tv.tv_sec + 491 tv.tv_usec) >> exp); 492 } 493 } 494 /* Now normalize and pack the value into an IEEE-754 float. */ 495 norm_exp = fls(val) - 1; 496 shift = FLT_MANT_DIG - norm_exp - 1; 497 #ifdef ACCT_DEBUG 498 printf("val=%d exp=%d shift=%d log2(val)=%d\n", 499 val, exp, shift, norm_exp); 500 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 501 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 502 #endif 503 return (((FLT_MAX_EXP - 1 + exp + norm_exp) << (FLT_MANT_DIG - 1)) | 504 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 505 } 506 507 /* 508 * Convert a non-negative long value into the bit pattern of 509 * an IEEE-754 float value. 510 */ 511 static uint32_t 512 encode_long(long val) 513 { 514 int norm_exp; /* Normalized exponent */ 515 int shift; 516 517 if (val == 0) 518 return (0); 519 if (val < 0) { 520 log(LOG_NOTICE, 521 "encode_long: negative value %ld in accounting record\n", 522 val); 523 val = LONG_MAX; 524 } 525 norm_exp = fls(val) - 1; 526 shift = FLT_MANT_DIG - norm_exp - 1; 527 #ifdef ACCT_DEBUG 528 printf("val=%d shift=%d log2(val)=%d\n", 529 val, shift, norm_exp); 530 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 531 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 532 #endif 533 return (((FLT_MAX_EXP - 1 + norm_exp) << (FLT_MANT_DIG - 1)) | 534 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 535 } 536 537 /* FLOAT_CONVERSION_END (Regression testing; don't remove this line.) */ 538 539 /* 540 * Periodically check the filesystem to see if accounting 541 * should be turned on or off. Beware the case where the vnode 542 * has been vgone()'d out from underneath us, e.g. when the file 543 * system containing the accounting file has been forcibly unmounted. 544 */ 545 /* ARGSUSED */ 546 static void 547 acctwatch(void) 548 { 549 struct statfs *sp; 550 551 sx_assert(&acct_sx, SX_XLOCKED); 552 553 /* 554 * If accounting was disabled before our kthread was scheduled, 555 * then acct_vp might be NULL. If so, just ask our kthread to 556 * exit and return. 557 */ 558 if (acct_vp == NULL) { 559 acct_state |= ACCT_EXITREQ; 560 return; 561 } 562 563 /* 564 * If our vnode is no longer valid, tear it down and signal the 565 * accounting thread to die. 566 */ 567 if (acct_vp->v_type == VBAD) { 568 (void) acct_disable(NULL, 1); 569 acct_state |= ACCT_EXITREQ; 570 return; 571 } 572 573 /* 574 * Stopping here is better than continuing, maybe it will be VBAD 575 * next time around. 576 */ 577 sp = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK); 578 if (VFS_STATFS(acct_vp->v_mount, sp) < 0) { 579 free(sp, M_STATFS); 580 return; 581 } 582 if (acct_suspended) { 583 if (sp->f_bavail > (int64_t)(acctresume * sp->f_blocks / 584 100)) { 585 acct_suspended = 0; 586 log(LOG_NOTICE, "Accounting resumed\n"); 587 } 588 } else { 589 if (sp->f_bavail <= (int64_t)(acctsuspend * sp->f_blocks / 590 100)) { 591 acct_suspended = 1; 592 log(LOG_NOTICE, "Accounting suspended\n"); 593 } 594 } 595 free(sp, M_STATFS); 596 } 597 598 /* 599 * The main loop for the dedicated kernel thread that periodically calls 600 * acctwatch(). 601 */ 602 static void 603 acct_thread(void *dummy) 604 { 605 u_char pri; 606 607 /* This is a low-priority kernel thread. */ 608 pri = PRI_MAX_KERN; 609 thread_lock(curthread); 610 sched_prio(curthread, pri); 611 thread_unlock(curthread); 612 613 /* If another accounting kthread is already running, just die. */ 614 sx_xlock(&acct_sx); 615 if (acct_state & ACCT_RUNNING) { 616 sx_xunlock(&acct_sx); 617 kproc_exit(0); 618 } 619 acct_state |= ACCT_RUNNING; 620 621 /* Loop until we are asked to exit. */ 622 while (!(acct_state & ACCT_EXITREQ)) { 623 /* Perform our periodic checks. */ 624 acctwatch(); 625 626 /* 627 * We check this flag again before sleeping since the 628 * acctwatch() might have shut down accounting and asked us 629 * to exit. 630 */ 631 if (!(acct_state & ACCT_EXITREQ)) { 632 sx_sleep(&acct_state, &acct_sx, 0, "-", 633 acctchkfreq * hz); 634 } 635 } 636 637 /* 638 * Acknowledge the exit request and shutdown. We clear both the 639 * exit request and running flags. 640 */ 641 acct_state = 0; 642 sx_xunlock(&acct_sx); 643 kproc_exit(0); 644 } 645