1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * Copyright (c) 2005 Robert N. M. Watson 6 * All rights reserved. 7 * 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. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * Copyright (c) 1994 Christopher G. Demetriou 38 * 39 * Redistribution and use in source and binary forms, with or without 40 * modification, are permitted provided that the following conditions 41 * are met: 42 * 1. Redistributions of source code must retain the above copyright 43 * notice, this list of conditions and the following disclaimer. 44 * 2. Redistributions in binary form must reproduce the above copyright 45 * notice, this list of conditions and the following disclaimer in the 46 * documentation and/or other materials provided with the distribution. 47 * 3. All advertising materials mentioning features or use of this software 48 * must display the following acknowledgement: 49 * This product includes software developed by the University of 50 * California, Berkeley and its contributors. 51 * 4. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 68 */ 69 70 #include <sys/cdefs.h> 71 __FBSDID("$FreeBSD$"); 72 73 #include <sys/param.h> 74 #include <sys/systm.h> 75 #include <sys/acct.h> 76 #include <sys/fcntl.h> 77 #include <sys/kernel.h> 78 #include <sys/kthread.h> 79 #include <sys/limits.h> 80 #include <sys/lock.h> 81 #include <sys/malloc.h> 82 #include <sys/mount.h> 83 #include <sys/mutex.h> 84 #include <sys/namei.h> 85 #include <sys/priv.h> 86 #include <sys/proc.h> 87 #include <sys/resourcevar.h> 88 #include <sys/sched.h> 89 #include <sys/sx.h> 90 #include <sys/sysctl.h> 91 #include <sys/sysent.h> 92 #include <sys/syslog.h> 93 #include <sys/sysproto.h> 94 #include <sys/tty.h> 95 #include <sys/vnode.h> 96 97 #include <security/mac/mac_framework.h> 98 99 /* 100 * The routines implemented in this file are described in: 101 * Leffler, et al.: The Design and Implementation of the 4.3BSD 102 * UNIX Operating System (Addison Welley, 1989) 103 * on pages 62-63. 104 * On May 2007 the historic 3 bits base 8 exponent, 13 bit fraction 105 * compt_t representation described in the above reference was replaced 106 * with that of IEEE-754 floats. 107 * 108 * Arguably, to simplify accounting operations, this mechanism should 109 * be replaced by one in which an accounting log file (similar to /dev/klog) 110 * is read by a user process, etc. However, that has its own problems. 111 */ 112 113 /* Floating point definitions from <float.h>. */ 114 #define FLT_MANT_DIG 24 /* p */ 115 #define FLT_MAX_EXP 128 /* emax */ 116 117 /* 118 * Internal accounting functions. 119 * The former's operation is described in Leffler, et al., and the latter 120 * was provided by UCB with the 4.4BSD-Lite release 121 */ 122 static uint32_t encode_timeval(struct timeval); 123 static uint32_t encode_long(long); 124 static void acctwatch(void); 125 static void acct_thread(void *); 126 static int acct_disable(struct thread *, int); 127 128 /* 129 * Accounting vnode pointer, saved vnode pointer, and flags for each. 130 * acct_sx protects against changes to the active vnode and credentials 131 * while accounting records are being committed to disk. 132 */ 133 static int acct_configured; 134 static int acct_suspended; 135 static struct vnode *acct_vp; 136 static struct ucred *acct_cred; 137 static struct plimit *acct_limit; 138 static int acct_flags; 139 static struct sx acct_sx; 140 141 SX_SYSINIT(acct, &acct_sx, "acct_sx"); 142 143 /* 144 * State of the accounting kthread. 145 */ 146 static int acct_state; 147 148 #define ACCT_RUNNING 1 /* Accounting kthread is running. */ 149 #define ACCT_EXITREQ 2 /* Accounting kthread should exit. */ 150 151 /* 152 * Values associated with enabling and disabling accounting 153 */ 154 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 155 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 156 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 157 158 static int acctresume = 4; /* resume when free space risen to > 4% */ 159 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 160 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 161 162 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 163 164 static int 165 sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS) 166 { 167 int error, value; 168 169 /* Write out the old value. */ 170 error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int)); 171 if (error || req->newptr == NULL) 172 return (error); 173 174 /* Read in and verify the new value. */ 175 error = SYSCTL_IN(req, &value, sizeof(int)); 176 if (error) 177 return (error); 178 if (value <= 0) 179 return (EINVAL); 180 acctchkfreq = value; 181 return (0); 182 } 183 SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq, CTLTYPE_INT|CTLFLAG_RW, 184 &acctchkfreq, 0, sysctl_acct_chkfreq, "I", 185 "frequency for checking the free space"); 186 187 SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0, 188 "Accounting configured or not"); 189 190 SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0, 191 "Accounting suspended or not"); 192 193 /* 194 * Accounting system call. Written based on the specification and previous 195 * implementation done by Mark Tinguely. 196 */ 197 int 198 sys_acct(struct thread *td, struct acct_args *uap) 199 { 200 struct nameidata nd; 201 int error, flags, i, replacing; 202 203 error = priv_check(td, PRIV_ACCT); 204 if (error) 205 return (error); 206 207 /* 208 * If accounting is to be started to a file, open that file for 209 * appending and make sure it's a 'normal'. 210 */ 211 if (uap->path != NULL) { 212 NDINIT(&nd, LOOKUP, NOFOLLOW | AUDITVNODE1, 213 UIO_USERSPACE, uap->path, td); 214 flags = FWRITE | O_APPEND; 215 error = vn_open(&nd, &flags, 0, NULL); 216 if (error) 217 return (error); 218 NDFREE(&nd, NDF_ONLY_PNBUF); 219 #ifdef MAC 220 error = mac_system_check_acct(td->td_ucred, nd.ni_vp); 221 if (error) { 222 VOP_UNLOCK(nd.ni_vp, 0); 223 vn_close(nd.ni_vp, flags, td->td_ucred, td); 224 return (error); 225 } 226 #endif 227 VOP_UNLOCK(nd.ni_vp, 0); 228 if (nd.ni_vp->v_type != VREG) { 229 vn_close(nd.ni_vp, flags, td->td_ucred, td); 230 return (EACCES); 231 } 232 #ifdef MAC 233 } else { 234 error = mac_system_check_acct(td->td_ucred, NULL); 235 if (error) 236 return (error); 237 #endif 238 } 239 240 /* 241 * Disallow concurrent access to the accounting vnode while we swap 242 * it out, in order to prevent access after close. 243 */ 244 sx_xlock(&acct_sx); 245 246 /* 247 * Don't log spurious disable/enable messages if we are 248 * switching from one accounting file to another due to log 249 * rotation. 250 */ 251 replacing = (acct_vp != NULL && uap->path != NULL); 252 253 /* 254 * If accounting was previously enabled, kill the old space-watcher, 255 * close the file, and (if no new file was specified, leave). Reset 256 * the suspended state regardless of whether accounting remains 257 * enabled. 258 */ 259 acct_suspended = 0; 260 if (acct_vp != NULL) 261 error = acct_disable(td, !replacing); 262 if (uap->path == NULL) { 263 if (acct_state & ACCT_RUNNING) { 264 acct_state |= ACCT_EXITREQ; 265 wakeup(&acct_state); 266 } 267 sx_xunlock(&acct_sx); 268 return (error); 269 } 270 271 /* 272 * Create our own plimit object without limits. It will be assigned 273 * to exiting processes. 274 */ 275 acct_limit = lim_alloc(); 276 for (i = 0; i < RLIM_NLIMITS; i++) 277 acct_limit->pl_rlimit[i].rlim_cur = 278 acct_limit->pl_rlimit[i].rlim_max = RLIM_INFINITY; 279 280 /* 281 * Save the new accounting file vnode, and schedule the new 282 * free space watcher. 283 */ 284 acct_vp = nd.ni_vp; 285 acct_cred = crhold(td->td_ucred); 286 acct_flags = flags; 287 if (acct_state & ACCT_RUNNING) 288 acct_state &= ~ACCT_EXITREQ; 289 else { 290 /* 291 * Try to start up an accounting kthread. We may start more 292 * than one, but if so the extras will commit suicide as 293 * soon as they start up. 294 */ 295 error = kproc_create(acct_thread, NULL, NULL, 0, 0, 296 "accounting"); 297 if (error) { 298 (void) acct_disable(td, 0); 299 sx_xunlock(&acct_sx); 300 log(LOG_NOTICE, "Unable to start accounting thread\n"); 301 return (error); 302 } 303 } 304 acct_configured = 1; 305 sx_xunlock(&acct_sx); 306 if (!replacing) 307 log(LOG_NOTICE, "Accounting enabled\n"); 308 return (error); 309 } 310 311 /* 312 * Disable currently in-progress accounting by closing the vnode, dropping 313 * our reference to the credential, and clearing the vnode's flags. 314 */ 315 static int 316 acct_disable(struct thread *td, int logging) 317 { 318 int error; 319 320 sx_assert(&acct_sx, SX_XLOCKED); 321 error = vn_close(acct_vp, acct_flags, acct_cred, td); 322 crfree(acct_cred); 323 lim_free(acct_limit); 324 acct_configured = 0; 325 acct_vp = NULL; 326 acct_cred = NULL; 327 acct_flags = 0; 328 if (logging) 329 log(LOG_NOTICE, "Accounting disabled\n"); 330 return (error); 331 } 332 333 /* 334 * Write out process accounting information, on process exit. 335 * Data to be written out is specified in Leffler, et al. 336 * and are enumerated below. (They're also noted in the system 337 * "acct.h" header file.) 338 */ 339 int 340 acct_process(struct thread *td) 341 { 342 struct acctv2 acct; 343 struct timeval ut, st, tmp; 344 struct plimit *oldlim; 345 struct proc *p; 346 struct rusage ru; 347 int t, ret; 348 349 /* 350 * Lockless check of accounting condition before doing the hard 351 * work. 352 */ 353 if (acct_vp == NULL || acct_suspended) 354 return (0); 355 356 sx_slock(&acct_sx); 357 358 /* 359 * If accounting isn't enabled, don't bother. Have to check again 360 * once we own the lock in case we raced with disabling of accounting 361 * by another thread. 362 */ 363 if (acct_vp == NULL || acct_suspended) { 364 sx_sunlock(&acct_sx); 365 return (0); 366 } 367 368 p = td->td_proc; 369 370 /* 371 * Get process accounting information. 372 */ 373 374 sx_slock(&proctree_lock); 375 PROC_LOCK(p); 376 377 /* (1) The terminal from which the process was started */ 378 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 379 acct.ac_tty = tty_udev(p->p_pgrp->pg_session->s_ttyp); 380 else 381 acct.ac_tty = NODEV; 382 sx_sunlock(&proctree_lock); 383 384 /* (2) The name of the command that ran */ 385 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 386 387 /* (3) The amount of user and system time that was used */ 388 rufetchcalc(p, &ru, &ut, &st); 389 acct.ac_utime = encode_timeval(ut); 390 acct.ac_stime = encode_timeval(st); 391 392 /* (4) The elapsed time the command ran (and its starting time) */ 393 getboottime(&tmp); 394 timevaladd(&tmp, &p->p_stats->p_start); 395 acct.ac_btime = tmp.tv_sec; 396 microuptime(&tmp); 397 timevalsub(&tmp, &p->p_stats->p_start); 398 acct.ac_etime = encode_timeval(tmp); 399 400 /* (5) The average amount of memory used */ 401 tmp = ut; 402 timevaladd(&tmp, &st); 403 /* Convert tmp (i.e. u + s) into hz units to match ru_i*. */ 404 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 405 if (t) 406 acct.ac_mem = encode_long((ru.ru_ixrss + ru.ru_idrss + 407 + ru.ru_isrss) / t); 408 else 409 acct.ac_mem = 0; 410 411 /* (6) The number of disk I/O operations done */ 412 acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock); 413 414 /* (7) The UID and GID of the process */ 415 acct.ac_uid = p->p_ucred->cr_ruid; 416 acct.ac_gid = p->p_ucred->cr_rgid; 417 418 /* (8) The boolean flags that tell how the process terminated, etc. */ 419 acct.ac_flagx = p->p_acflag; 420 421 /* Setup ancillary structure fields. */ 422 acct.ac_flagx |= ANVER; 423 acct.ac_zero = 0; 424 acct.ac_version = 2; 425 acct.ac_len = acct.ac_len2 = sizeof(acct); 426 427 /* 428 * Eliminate rlimits (file size limit in particular). 429 */ 430 oldlim = p->p_limit; 431 p->p_limit = lim_hold(acct_limit); 432 PROC_UNLOCK(p); 433 lim_free(oldlim); 434 435 /* 436 * Write the accounting information to the file. 437 */ 438 ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct), 439 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED, 440 NULL, td); 441 sx_sunlock(&acct_sx); 442 return (ret); 443 } 444 445 /* FLOAT_CONVERSION_START (Regression testing; don't remove this line.) */ 446 447 /* Convert timevals and longs into IEEE-754 bit patterns. */ 448 449 /* Mantissa mask (MSB is implied, so subtract 1). */ 450 #define MANT_MASK ((1 << (FLT_MANT_DIG - 1)) - 1) 451 452 /* 453 * We calculate integer values to a precision of approximately 454 * 28 bits. 455 * This is high-enough precision to fill the 24 float bits 456 * and low-enough to avoid overflowing the 32 int bits. 457 */ 458 #define CALC_BITS 28 459 460 /* log_2(1000000). */ 461 #define LOG2_1M 20 462 463 /* 464 * Convert the elements of a timeval into a 32-bit word holding 465 * the bits of a IEEE-754 float. 466 * The float value represents the timeval's value in microsecond units. 467 */ 468 static uint32_t 469 encode_timeval(struct timeval tv) 470 { 471 int log2_s; 472 int val, exp; /* Unnormalized value and exponent */ 473 int norm_exp; /* Normalized exponent */ 474 int shift; 475 476 /* 477 * First calculate value and exponent to about CALC_BITS precision. 478 * Note that the following conditionals have been ordered so that 479 * the most common cases appear first. 480 */ 481 if (tv.tv_sec == 0) { 482 if (tv.tv_usec == 0) 483 return (0); 484 exp = 0; 485 val = tv.tv_usec; 486 } else { 487 /* 488 * Calculate the value to a precision of approximately 489 * CALC_BITS. 490 */ 491 log2_s = fls(tv.tv_sec) - 1; 492 if (log2_s + LOG2_1M < CALC_BITS) { 493 exp = 0; 494 val = 1000000 * tv.tv_sec + tv.tv_usec; 495 } else { 496 exp = log2_s + LOG2_1M - CALC_BITS; 497 val = (unsigned int)(((uint64_t)1000000 * tv.tv_sec + 498 tv.tv_usec) >> exp); 499 } 500 } 501 /* Now normalize and pack the value into an IEEE-754 float. */ 502 norm_exp = fls(val) - 1; 503 shift = FLT_MANT_DIG - norm_exp - 1; 504 #ifdef ACCT_DEBUG 505 printf("val=%d exp=%d shift=%d log2(val)=%d\n", 506 val, exp, shift, norm_exp); 507 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 508 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 509 #endif 510 return (((FLT_MAX_EXP - 1 + exp + norm_exp) << (FLT_MANT_DIG - 1)) | 511 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 512 } 513 514 /* 515 * Convert a non-negative long value into the bit pattern of 516 * an IEEE-754 float value. 517 */ 518 static uint32_t 519 encode_long(long val) 520 { 521 int norm_exp; /* Normalized exponent */ 522 int shift; 523 524 if (val == 0) 525 return (0); 526 if (val < 0) { 527 log(LOG_NOTICE, 528 "encode_long: negative value %ld in accounting record\n", 529 val); 530 val = LONG_MAX; 531 } 532 norm_exp = fls(val) - 1; 533 shift = FLT_MANT_DIG - norm_exp - 1; 534 #ifdef ACCT_DEBUG 535 printf("val=%d shift=%d log2(val)=%d\n", 536 val, shift, norm_exp); 537 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 538 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 539 #endif 540 return (((FLT_MAX_EXP - 1 + norm_exp) << (FLT_MANT_DIG - 1)) | 541 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 542 } 543 544 /* FLOAT_CONVERSION_END (Regression testing; don't remove this line.) */ 545 546 /* 547 * Periodically check the filesystem to see if accounting 548 * should be turned on or off. Beware the case where the vnode 549 * has been vgone()'d out from underneath us, e.g. when the file 550 * system containing the accounting file has been forcibly unmounted. 551 */ 552 /* ARGSUSED */ 553 static void 554 acctwatch(void) 555 { 556 struct statfs *sp; 557 558 sx_assert(&acct_sx, SX_XLOCKED); 559 560 /* 561 * If accounting was disabled before our kthread was scheduled, 562 * then acct_vp might be NULL. If so, just ask our kthread to 563 * exit and return. 564 */ 565 if (acct_vp == NULL) { 566 acct_state |= ACCT_EXITREQ; 567 return; 568 } 569 570 /* 571 * If our vnode is no longer valid, tear it down and signal the 572 * accounting thread to die. 573 */ 574 if (acct_vp->v_type == VBAD) { 575 (void) acct_disable(NULL, 1); 576 acct_state |= ACCT_EXITREQ; 577 return; 578 } 579 580 /* 581 * Stopping here is better than continuing, maybe it will be VBAD 582 * next time around. 583 */ 584 sp = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK); 585 if (VFS_STATFS(acct_vp->v_mount, sp) < 0) { 586 free(sp, M_STATFS); 587 return; 588 } 589 if (acct_suspended) { 590 if (sp->f_bavail > (int64_t)(acctresume * sp->f_blocks / 591 100)) { 592 acct_suspended = 0; 593 log(LOG_NOTICE, "Accounting resumed\n"); 594 } 595 } else { 596 if (sp->f_bavail <= (int64_t)(acctsuspend * sp->f_blocks / 597 100)) { 598 acct_suspended = 1; 599 log(LOG_NOTICE, "Accounting suspended\n"); 600 } 601 } 602 free(sp, M_STATFS); 603 } 604 605 /* 606 * The main loop for the dedicated kernel thread that periodically calls 607 * acctwatch(). 608 */ 609 static void 610 acct_thread(void *dummy) 611 { 612 u_char pri; 613 614 /* This is a low-priority kernel thread. */ 615 pri = PRI_MAX_KERN; 616 thread_lock(curthread); 617 sched_prio(curthread, pri); 618 thread_unlock(curthread); 619 620 /* If another accounting kthread is already running, just die. */ 621 sx_xlock(&acct_sx); 622 if (acct_state & ACCT_RUNNING) { 623 sx_xunlock(&acct_sx); 624 kproc_exit(0); 625 } 626 acct_state |= ACCT_RUNNING; 627 628 /* Loop until we are asked to exit. */ 629 while (!(acct_state & ACCT_EXITREQ)) { 630 631 /* Perform our periodic checks. */ 632 acctwatch(); 633 634 /* 635 * We check this flag again before sleeping since the 636 * acctwatch() might have shut down accounting and asked us 637 * to exit. 638 */ 639 if (!(acct_state & ACCT_EXITREQ)) { 640 sx_sleep(&acct_state, &acct_sx, 0, "-", 641 acctchkfreq * hz); 642 } 643 } 644 645 /* 646 * Acknowledge the exit request and shutdown. We clear both the 647 * exit request and running flags. 648 */ 649 acct_state = 0; 650 sx_xunlock(&acct_sx); 651 kproc_exit(0); 652 } 653