kern_acct.c revision 170174
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 * 4. 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: head/sys/kern/kern_acct.c 170174 2007-06-01 01:12:45Z jeff $"); 72 73#include "opt_mac.h" 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/lock.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 */ 122static uint32_t encode_timeval(struct timeval); 123static uint32_t encode_long(long); 124static void acctwatch(void); 125static void acct_thread(void *); 126static int acct_disable(struct thread *); 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 */ 133static int acct_configured; 134static int acct_suspended; 135static struct vnode *acct_vp; 136static struct ucred *acct_cred; 137static int acct_flags; 138static struct sx acct_sx; 139 140SX_SYSINIT(acct, &acct_sx, "acct_sx"); 141 142/* 143 * State of the accounting kthread. 144 */ 145static int acct_state; 146 147#define ACCT_RUNNING 1 /* Accounting kthread is running. */ 148#define ACCT_EXITREQ 2 /* Accounting kthread should exit. */ 149 150/* 151 * Values associated with enabling and disabling accounting 152 */ 153static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 154SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 155 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 156 157static int acctresume = 4; /* resume when free space risen to > 4% */ 158SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 159 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 160 161static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 162 163static int 164sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS) 165{ 166 int error, value; 167 168 /* Write out the old value. */ 169 error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int)); 170 if (error || req->newptr == NULL) 171 return (error); 172 173 /* Read in and verify the new value. */ 174 error = SYSCTL_IN(req, &value, sizeof(int)); 175 if (error) 176 return (error); 177 if (value <= 0) 178 return (EINVAL); 179 acctchkfreq = value; 180 return (0); 181} 182SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq, CTLTYPE_INT|CTLFLAG_RW, 183 &acctchkfreq, 0, sysctl_acct_chkfreq, "I", 184 "frequency for checking the free space"); 185 186SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0, 187 "Accounting configured or not"); 188 189SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0, 190 "Accounting suspended or not"); 191 192/* 193 * Accounting system call. Written based on the specification and previous 194 * implementation done by Mark Tinguely. 195 */ 196int 197acct(struct thread *td, struct acct_args *uap) 198{ 199 struct nameidata nd; 200 int error, flags, vfslocked; 201 202 error = priv_check(td, PRIV_ACCT); 203 if (error) 204 return (error); 205 206 /* 207 * If accounting is to be started to a file, open that file for 208 * appending and make sure it's a 'normal'. 209 */ 210 if (uap->path != NULL) { 211 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE | AUDITVNODE1, 212 UIO_USERSPACE, uap->path, td); 213 flags = FWRITE | O_APPEND; 214 error = vn_open(&nd, &flags, 0, NULL); 215 if (error) 216 return (error); 217 vfslocked = NDHASGIANT(&nd); 218 NDFREE(&nd, NDF_ONLY_PNBUF); 219#ifdef MAC 220 error = mac_check_system_acct(td->td_ucred, nd.ni_vp); 221 if (error) { 222 VOP_UNLOCK(nd.ni_vp, 0, td); 223 vn_close(nd.ni_vp, flags, td->td_ucred, td); 224 VFS_UNLOCK_GIANT(vfslocked); 225 return (error); 226 } 227#endif 228 VOP_UNLOCK(nd.ni_vp, 0, td); 229 if (nd.ni_vp->v_type != VREG) { 230 vn_close(nd.ni_vp, flags, td->td_ucred, td); 231 VFS_UNLOCK_GIANT(vfslocked); 232 return (EACCES); 233 } 234 VFS_UNLOCK_GIANT(vfslocked); 235#ifdef MAC 236 } else { 237 error = mac_check_system_acct(td->td_ucred, NULL); 238 if (error) 239 return (error); 240#endif 241 } 242 243 /* 244 * Disallow concurrent access to the accounting vnode while we swap 245 * it out, in order to prevent access after close. 246 */ 247 sx_xlock(&acct_sx); 248 249 /* 250 * If accounting was previously enabled, kill the old space-watcher, 251 * close the file, and (if no new file was specified, leave). Reset 252 * the suspended state regardless of whether accounting remains 253 * enabled. 254 */ 255 acct_suspended = 0; 256 if (acct_vp != NULL) { 257 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount); 258 error = acct_disable(td); 259 VFS_UNLOCK_GIANT(vfslocked); 260 } 261 if (uap->path == NULL) { 262 if (acct_state & ACCT_RUNNING) { 263 acct_state |= ACCT_EXITREQ; 264 wakeup(&acct_state); 265 } 266 sx_xunlock(&acct_sx); 267 return (error); 268 } 269 270 /* 271 * Save the new accounting file vnode, and schedule the new 272 * free space watcher. 273 */ 274 acct_vp = nd.ni_vp; 275 acct_cred = crhold(td->td_ucred); 276 acct_flags = flags; 277 if (acct_state & ACCT_RUNNING) 278 acct_state &= ~ACCT_EXITREQ; 279 else { 280 /* 281 * Try to start up an accounting kthread. We may start more 282 * than one, but if so the extras will commit suicide as 283 * soon as they start up. 284 */ 285 error = kthread_create(acct_thread, NULL, NULL, 0, 0, 286 "accounting"); 287 if (error) { 288 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount); 289 (void) vn_close(acct_vp, acct_flags, acct_cred, td); 290 VFS_UNLOCK_GIANT(vfslocked); 291 crfree(acct_cred); 292 acct_configured = 0; 293 acct_vp = NULL; 294 acct_cred = NULL; 295 acct_flags = 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 log(LOG_NOTICE, "Accounting enabled\n"); 304 return (error); 305} 306 307/* 308 * Disable currently in-progress accounting by closing the vnode, dropping 309 * our reference to the credential, and clearing the vnode's flags. 310 */ 311static int 312acct_disable(struct thread *td) 313{ 314 int error; 315 316 sx_assert(&acct_sx, SX_XLOCKED); 317 error = vn_close(acct_vp, acct_flags, acct_cred, td); 318 crfree(acct_cred); 319 acct_configured = 0; 320 acct_vp = NULL; 321 acct_cred = NULL; 322 acct_flags = 0; 323 log(LOG_NOTICE, "Accounting disabled\n"); 324 return (error); 325} 326 327/* 328 * Write out process accounting information, on process exit. 329 * Data to be written out is specified in Leffler, et al. 330 * and are enumerated below. (They're also noted in the system 331 * "acct.h" header file.) 332 */ 333int 334acct_process(struct thread *td) 335{ 336 struct acctv2 acct; 337 struct timeval ut, st, tmp; 338 struct plimit *newlim, *oldlim; 339 struct proc *p; 340 struct rusage ru; 341 int t, ret, vfslocked; 342 343 /* 344 * Lockless check of accounting condition before doing the hard 345 * work. 346 */ 347 if (acct_vp == NULL || acct_suspended) 348 return (0); 349 350 sx_slock(&acct_sx); 351 352 /* 353 * If accounting isn't enabled, don't bother. Have to check again 354 * once we own the lock in case we raced with disabling of accounting 355 * by another thread. 356 */ 357 if (acct_vp == NULL || acct_suspended) { 358 sx_sunlock(&acct_sx); 359 return (0); 360 } 361 362 p = td->td_proc; 363 364 /* 365 * Get process accounting information. 366 */ 367 368 PROC_LOCK(p); 369 /* (1) The name of the command that ran */ 370 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 371 372 /* (2) The amount of user and system time that was used */ 373 rufetch(p, &ru); 374 calcru(p, &ut, &st); 375 acct.ac_utime = encode_timeval(ut); 376 acct.ac_stime = encode_timeval(st); 377 378 /* (3) The elapsed time the command ran (and its starting time) */ 379 tmp = boottime; 380 timevaladd(&tmp, &p->p_stats->p_start); 381 acct.ac_btime = tmp.tv_sec; 382 microuptime(&tmp); 383 timevalsub(&tmp, &p->p_stats->p_start); 384 acct.ac_etime = encode_timeval(tmp); 385 386 /* (4) The average amount of memory used */ 387 tmp = ut; 388 timevaladd(&tmp, &st); 389 /* Convert tmp (i.e. u + s) into hz units to match ru_i*. */ 390 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 391 if (t) 392 acct.ac_mem = encode_long((ru.ru_ixrss + ru.ru_idrss + 393 + ru.ru_isrss) / t); 394 else 395 acct.ac_mem = 0; 396 397 /* (5) The number of disk I/O operations done */ 398 acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock); 399 400 /* (6) The UID and GID of the process */ 401 acct.ac_uid = p->p_ucred->cr_ruid; 402 acct.ac_gid = p->p_ucred->cr_rgid; 403 404 /* (7) The terminal from which the process was started */ 405 SESS_LOCK(p->p_session); 406 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 407 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 408 else 409 acct.ac_tty = NODEV; 410 SESS_UNLOCK(p->p_session); 411 412 /* (8) The boolean flags that tell how the process terminated, etc. */ 413 acct.ac_flagx = p->p_acflag; 414 PROC_UNLOCK(p); 415 416 /* Setup ancillary structure fields. */ 417 acct.ac_flagx |= ANVER; 418 acct.ac_zero = 0; 419 acct.ac_version = 2; 420 acct.ac_len = acct.ac_len2 = sizeof(acct); 421 422 /* 423 * Eliminate any file size rlimit. 424 */ 425 newlim = lim_alloc(); 426 PROC_LOCK(p); 427 oldlim = p->p_limit; 428 lim_copy(newlim, oldlim); 429 newlim->pl_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 430 p->p_limit = newlim; 431 PROC_UNLOCK(p); 432 lim_free(oldlim); 433 434 /* 435 * Write the accounting information to the file. 436 */ 437 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount); 438 VOP_LEASE(acct_vp, td, acct_cred, LEASE_WRITE); 439 ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct), 440 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED, 441 (int *)0, td); 442 VFS_UNLOCK_GIANT(vfslocked); 443 sx_sunlock(&acct_sx); 444 return (ret); 445} 446 447/* FLOAT_CONVERSION_START (Regression testing; don't remove this line.) */ 448 449/* Convert timevals and longs into IEEE-754 bit patterns. */ 450 451/* Mantissa mask (MSB is implied, so subtract 1). */ 452#define MANT_MASK ((1 << (FLT_MANT_DIG - 1)) - 1) 453 454/* 455 * We calculate integer values to a precision of approximately 456 * 28 bits. 457 * This is high-enough precision to fill the 24 float bits 458 * and low-enough to avoid overflowing the 32 int bits. 459 */ 460#define CALC_BITS 28 461 462/* log_2(1000000). */ 463#define LOG2_1M 20 464 465/* 466 * Convert the elements of a timeval into a 32-bit word holding 467 * the bits of a IEEE-754 float. 468 * The float value represents the timeval's value in microsecond units. 469 */ 470static uint32_t 471encode_timeval(struct timeval tv) 472{ 473 int log2_s; 474 int val, exp; /* Unnormalized value and exponent */ 475 int norm_exp; /* Normalized exponent */ 476 int shift; 477 478 /* 479 * First calculate value and exponent to about CALC_BITS precision. 480 * Note that the following conditionals have been ordered so that 481 * the most common cases appear first. 482 */ 483 if (tv.tv_sec == 0) { 484 if (tv.tv_usec == 0) 485 return (0); 486 exp = 0; 487 val = tv.tv_usec; 488 } else { 489 /* 490 * Calculate the value to a precision of approximately 491 * CALC_BITS. 492 */ 493 log2_s = fls(tv.tv_sec) - 1; 494 if (log2_s + LOG2_1M < CALC_BITS) { 495 exp = 0; 496 val = 1000000 * tv.tv_sec + tv.tv_usec; 497 } else { 498 exp = log2_s + LOG2_1M - CALC_BITS; 499 val = (unsigned int)(((u_int64_t)1000000 * tv.tv_sec + 500 tv.tv_usec) >> exp); 501 } 502 } 503 /* Now normalize and pack the value into an IEEE-754 float. */ 504 norm_exp = fls(val) - 1; 505 shift = FLT_MANT_DIG - norm_exp - 1; 506#ifdef ACCT_DEBUG 507 printf("val=%d exp=%d shift=%d log2(val)=%d\n", 508 val, exp, shift, norm_exp); 509 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 510 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 511#endif 512 return (((FLT_MAX_EXP - 1 + exp + norm_exp) << (FLT_MANT_DIG - 1)) | 513 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 514} 515 516/* 517 * Convert a non-negative long value into the bit pattern of 518 * an IEEE-754 float value. 519 */ 520static uint32_t 521encode_long(long val) 522{ 523 int norm_exp; /* Normalized exponent */ 524 int shift; 525 526 KASSERT(val >= 0, ("encode_long: -ve value %ld", val)); 527 if (val == 0) 528 return (0); 529 norm_exp = fls(val) - 1; 530 shift = FLT_MANT_DIG - norm_exp - 1; 531#ifdef ACCT_DEBUG 532 printf("val=%d shift=%d log2(val)=%d\n", 533 val, shift, norm_exp); 534 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 535 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 536#endif 537 return (((FLT_MAX_EXP - 1 + norm_exp) << (FLT_MANT_DIG - 1)) | 538 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 539} 540 541/* FLOAT_CONVERSION_END (Regression testing; don't remove this line.) */ 542 543/* 544 * Periodically check the filesystem to see if accounting 545 * should be turned on or off. Beware the case where the vnode 546 * has been vgone()'d out from underneath us, e.g. when the file 547 * system containing the accounting file has been forcibly unmounted. 548 */ 549/* ARGSUSED */ 550static void 551acctwatch(void) 552{ 553 struct statfs sb; 554 int vfslocked; 555 556 sx_assert(&acct_sx, SX_XLOCKED); 557 558 /* 559 * If accounting was disabled before our kthread was scheduled, 560 * then acct_vp might be NULL. If so, just ask our kthread to 561 * exit and return. 562 */ 563 if (acct_vp == NULL) { 564 acct_state |= ACCT_EXITREQ; 565 return; 566 } 567 568 /* 569 * If our vnode is no longer valid, tear it down and signal the 570 * accounting thread to die. 571 */ 572 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount); 573 if (acct_vp->v_type == VBAD) { 574 (void) acct_disable(NULL); 575 VFS_UNLOCK_GIANT(vfslocked); 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 if (VFS_STATFS(acct_vp->v_mount, &sb, curthread) < 0) { 585 VFS_UNLOCK_GIANT(vfslocked); 586 return; 587 } 588 VFS_UNLOCK_GIANT(vfslocked); 589 if (acct_suspended) { 590 if (sb.f_bavail > (int64_t)(acctresume * sb.f_blocks / 591 100)) { 592 acct_suspended = 0; 593 log(LOG_NOTICE, "Accounting resumed\n"); 594 } 595 } else { 596 if (sb.f_bavail <= (int64_t)(acctsuspend * sb.f_blocks / 597 100)) { 598 acct_suspended = 1; 599 log(LOG_NOTICE, "Accounting suspended\n"); 600 } 601 } 602} 603 604/* 605 * The main loop for the dedicated kernel thread that periodically calls 606 * acctwatch(). 607 */ 608static void 609acct_thread(void *dummy) 610{ 611 u_char pri; 612 613 /* This is a low-priority kernel thread. */ 614 pri = PRI_MAX_KERN; 615 mtx_lock_spin(&sched_lock); 616 sched_prio(curthread, pri); 617 mtx_unlock_spin(&sched_lock); 618 619 /* If another accounting kthread is already running, just die. */ 620 sx_xlock(&acct_sx); 621 if (acct_state & ACCT_RUNNING) { 622 sx_xunlock(&acct_sx); 623 kthread_exit(0); 624 } 625 acct_state |= ACCT_RUNNING; 626 627 /* Loop until we are asked to exit. */ 628 while (!(acct_state & ACCT_EXITREQ)) { 629 630 /* Perform our periodic checks. */ 631 acctwatch(); 632 633 /* 634 * We check this flag again before sleeping since the 635 * acctwatch() might have shut down accounting and asked us 636 * to exit. 637 */ 638 if (!(acct_state & ACCT_EXITREQ)) { 639 sx_sleep(&acct_state, &acct_sx, 0, "-", 640 acctchkfreq * hz); 641 } 642 } 643 644 /* 645 * Acknowledge the exit request and shutdown. We clear both the 646 * exit request and running flags. 647 */ 648 acct_state = 0; 649 sx_xunlock(&acct_sx); 650 kthread_exit(0); 651} 652