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/sysent.h> 94#include <sys/syslog.h> 95#include <sys/sysproto.h> 96#include <sys/tty.h> 97#include <sys/vnode.h> 98 99#include <security/mac/mac_framework.h> 100 101_Static_assert(sizeof(struct acctv3) - offsetof(struct acctv3, ac_trailer) == 102 sizeof(struct acctv2) - offsetof(struct acctv2, ac_trailer), "trailer"); 103_Static_assert(sizeof(struct acctv3) - offsetof(struct acctv3, ac_len2) == 104 sizeof(struct acctv2) - offsetof(struct acctv2, ac_len2), "len2"); 105 106/* 107 * The routines implemented in this file are described in: 108 * Leffler, et al.: The Design and Implementation of the 4.3BSD 109 * UNIX Operating System (Addison Welley, 1989) 110 * on pages 62-63. 111 * On May 2007 the historic 3 bits base 8 exponent, 13 bit fraction 112 * compt_t representation described in the above reference was replaced 113 * with that of IEEE-754 floats. 114 * 115 * Arguably, to simplify accounting operations, this mechanism should 116 * be replaced by one in which an accounting log file (similar to /dev/klog) 117 * is read by a user process, etc. However, that has its own problems. 118 */ 119 120/* Floating point definitions from <float.h>. */ 121#define FLT_MANT_DIG 24 /* p */ 122#define FLT_MAX_EXP 128 /* emax */ 123 124/* 125 * Internal accounting functions. 126 * The former's operation is described in Leffler, et al., and the latter 127 * was provided by UCB with the 4.4BSD-Lite release 128 */ 129static uint32_t encode_timeval(struct timeval); 130static uint32_t encode_long(long); 131static void acctwatch(void); 132static void acct_thread(void *); 133static int acct_disable(struct thread *, int); 134 135/* 136 * Accounting vnode pointer, saved vnode pointer, and flags for each. 137 * acct_sx protects against changes to the active vnode and credentials 138 * while accounting records are being committed to disk. 139 */ 140static int acct_configured; 141static int acct_suspended; 142static struct vnode *acct_vp; 143static struct ucred *acct_cred; 144static struct plimit *acct_limit; 145static int acct_flags; 146static struct sx acct_sx; 147 148SX_SYSINIT(acct, &acct_sx, "acct_sx"); 149 150/* 151 * State of the accounting kthread. 152 */ 153static int acct_state; 154 155#define ACCT_RUNNING 1 /* Accounting kthread is running. */ 156#define ACCT_EXITREQ 2 /* Accounting kthread should exit. */ 157 158/* 159 * Values associated with enabling and disabling accounting 160 */ 161static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 162SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 163 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 164 165static int acctresume = 4; /* resume when free space risen to > 4% */ 166SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 167 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 168 169static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 170 171static int 172sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS) 173{ 174 int error, value; 175 176 /* Write out the old value. */ 177 error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int)); 178 if (error || req->newptr == NULL) 179 return (error); 180 181 /* Read in and verify the new value. */ 182 error = SYSCTL_IN(req, &value, sizeof(int)); 183 if (error) 184 return (error); 185 if (value <= 0) 186 return (EINVAL); 187 acctchkfreq = value; 188 return (0); 189} 190SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq, CTLTYPE_INT|CTLFLAG_RW, 191 &acctchkfreq, 0, sysctl_acct_chkfreq, "I", 192 "frequency for checking the free space"); 193 194SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0, 195 "Accounting configured or not"); 196 197SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0, 198 "Accounting suspended or not"); 199 200/* 201 * Accounting system call. Written based on the specification and previous 202 * implementation done by Mark Tinguely. 203 */ 204int 205sys_acct(struct thread *td, struct acct_args *uap) 206{ 207 struct nameidata nd; 208 int error, flags, i, replacing; 209 210 error = priv_check(td, PRIV_ACCT); 211 if (error) 212 return (error); 213 214 /* 215 * If accounting is to be started to a file, open that file for 216 * appending and make sure it's a 'normal'. 217 */ 218 if (uap->path != NULL) { 219 NDINIT(&nd, LOOKUP, NOFOLLOW | AUDITVNODE1, 220 UIO_USERSPACE, uap->path, td); 221 flags = FWRITE | O_APPEND; 222 error = vn_open(&nd, &flags, 0, NULL); 223 if (error) 224 return (error); 225 NDFREE(&nd, NDF_ONLY_PNBUF); 226#ifdef MAC 227 error = mac_system_check_acct(td->td_ucred, nd.ni_vp); 228 if (error) { 229 VOP_UNLOCK(nd.ni_vp, 0); 230 vn_close(nd.ni_vp, flags, td->td_ucred, td); 231 return (error); 232 } 233#endif 234 VOP_UNLOCK(nd.ni_vp, 0); 235 if (nd.ni_vp->v_type != VREG) { 236 vn_close(nd.ni_vp, flags, td->td_ucred, td); 237 return (EACCES); 238 } 239#ifdef MAC 240 } else { 241 error = mac_system_check_acct(td->td_ucred, NULL); 242 if (error) 243 return (error); 244#endif 245 } 246 247 /* 248 * Disallow concurrent access to the accounting vnode while we swap 249 * it out, in order to prevent access after close. 250 */ 251 sx_xlock(&acct_sx); 252 253 /* 254 * Don't log spurious disable/enable messages if we are 255 * switching from one accounting file to another due to log 256 * rotation. 257 */ 258 replacing = (acct_vp != NULL && uap->path != NULL); 259 260 /* 261 * If accounting was previously enabled, kill the old space-watcher, 262 * close the file, and (if no new file was specified, leave). Reset 263 * the suspended state regardless of whether accounting remains 264 * enabled. 265 */ 266 acct_suspended = 0; 267 if (acct_vp != NULL) 268 error = acct_disable(td, !replacing); 269 if (uap->path == NULL) { 270 if (acct_state & ACCT_RUNNING) { 271 acct_state |= ACCT_EXITREQ; 272 wakeup(&acct_state); 273 } 274 sx_xunlock(&acct_sx); 275 return (error); 276 } 277 278 /* 279 * Create our own plimit object without limits. It will be assigned 280 * to exiting processes. 281 */ 282 acct_limit = lim_alloc(); 283 for (i = 0; i < RLIM_NLIMITS; i++) 284 acct_limit->pl_rlimit[i].rlim_cur = 285 acct_limit->pl_rlimit[i].rlim_max = RLIM_INFINITY; 286 287 /* 288 * Save the new accounting file vnode, and schedule the new 289 * free space watcher. 290 */ 291 acct_vp = nd.ni_vp; 292 acct_cred = crhold(td->td_ucred); 293 acct_flags = flags; 294 if (acct_state & ACCT_RUNNING) 295 acct_state &= ~ACCT_EXITREQ; 296 else { 297 /* 298 * Try to start up an accounting kthread. We may start more 299 * than one, but if so the extras will commit suicide as 300 * soon as they start up. 301 */ 302 error = kproc_create(acct_thread, NULL, NULL, 0, 0, 303 "accounting"); 304 if (error) { 305 (void) acct_disable(td, 0); 306 sx_xunlock(&acct_sx); 307 log(LOG_NOTICE, "Unable to start accounting thread\n"); 308 return (error); 309 } 310 } 311 acct_configured = 1; 312 sx_xunlock(&acct_sx); 313 if (!replacing) 314 log(LOG_NOTICE, "Accounting enabled\n"); 315 return (error); 316} 317 318/* 319 * Disable currently in-progress accounting by closing the vnode, dropping 320 * our reference to the credential, and clearing the vnode's flags. 321 */ 322static int 323acct_disable(struct thread *td, int logging) 324{ 325 int error; 326 327 sx_assert(&acct_sx, SX_XLOCKED); 328 error = vn_close(acct_vp, acct_flags, acct_cred, td); 329 crfree(acct_cred); 330 lim_free(acct_limit); 331 acct_configured = 0; 332 acct_vp = NULL; 333 acct_cred = NULL; 334 acct_flags = 0; 335 if (logging) 336 log(LOG_NOTICE, "Accounting disabled\n"); 337 return (error); 338} 339 340/* 341 * Write out process accounting information, on process exit. 342 * Data to be written out is specified in Leffler, et al. 343 * and are enumerated below. (They're also noted in the system 344 * "acct.h" header file.) 345 */ 346int 347acct_process(struct thread *td) 348{ 349 struct acctv3 acct; 350 struct timeval ut, st, tmp; 351 struct plimit *oldlim; 352 struct proc *p; 353 struct rusage ru; 354 int t, ret; 355 356 /* 357 * Lockless check of accounting condition before doing the hard 358 * work. 359 */ 360 if (acct_vp == NULL || acct_suspended) 361 return (0); 362 363 sx_slock(&acct_sx); 364 365 /* 366 * If accounting isn't enabled, don't bother. Have to check again 367 * once we own the lock in case we raced with disabling of accounting 368 * by another thread. 369 */ 370 if (acct_vp == NULL || acct_suspended) { 371 sx_sunlock(&acct_sx); 372 return (0); 373 } 374 375 p = td->td_proc; 376 377 /* 378 * Get process accounting information. 379 */ 380 381 sx_slock(&proctree_lock); 382 PROC_LOCK(p); 383 384 /* (1) The terminal from which the process was started */ 385 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 386 acct.ac_tty = tty_udev(p->p_pgrp->pg_session->s_ttyp); 387 else 388 acct.ac_tty = NODEV; 389 sx_sunlock(&proctree_lock); 390 391 /* (2) The name of the command that ran */ 392 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 393 394 /* (3) The amount of user and system time that was used */ 395 rufetchcalc(p, &ru, &ut, &st); 396 acct.ac_utime = encode_timeval(ut); 397 acct.ac_stime = encode_timeval(st); 398 399 /* (4) The elapsed time the command ran (and its starting time) */ 400 getboottime(&tmp); 401 timevaladd(&tmp, &p->p_stats->p_start); 402 acct.ac_btime = tmp.tv_sec; 403 microuptime(&tmp); 404 timevalsub(&tmp, &p->p_stats->p_start); 405 acct.ac_etime = encode_timeval(tmp); 406 407 /* (5) The average amount of memory used */ 408 tmp = ut; 409 timevaladd(&tmp, &st); 410 /* Convert tmp (i.e. u + s) into hz units to match ru_i*. */ 411 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 412 if (t) 413 acct.ac_mem = encode_long((ru.ru_ixrss + ru.ru_idrss + 414 + ru.ru_isrss) / t); 415 else 416 acct.ac_mem = 0; 417 418 /* (6) The number of disk I/O operations done */ 419 acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock); 420 421 /* (7) The UID and GID of the process */ 422 acct.ac_uid = p->p_ucred->cr_ruid; 423 acct.ac_gid = p->p_ucred->cr_rgid; 424 425 /* (8) The boolean flags that tell how the process terminated, etc. */ 426 acct.ac_flagx = p->p_acflag; 427 428 /* Setup ancillary structure fields. */ 429 acct.ac_flagx |= ANVER; 430 acct.ac_zero = 0; 431 acct.ac_version = 3; 432 acct.ac_len = acct.ac_len2 = sizeof(acct); 433 434 /* 435 * Eliminate rlimits (file size limit in particular). 436 */ 437 oldlim = p->p_limit; 438 p->p_limit = lim_hold(acct_limit); 439 PROC_UNLOCK(p); 440 lim_free(oldlim); 441 442 /* 443 * Write the accounting information to the file. 444 */ 445 ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct), 446 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED, 447 NULL, td); 448 sx_sunlock(&acct_sx); 449 return (ret); 450} 451 452/* FLOAT_CONVERSION_START (Regression testing; don't remove this line.) */ 453 454/* Convert timevals and longs into IEEE-754 bit patterns. */ 455 456/* Mantissa mask (MSB is implied, so subtract 1). */ 457#define MANT_MASK ((1 << (FLT_MANT_DIG - 1)) - 1) 458 459/* 460 * We calculate integer values to a precision of approximately 461 * 28 bits. 462 * This is high-enough precision to fill the 24 float bits 463 * and low-enough to avoid overflowing the 32 int bits. 464 */ 465#define CALC_BITS 28 466 467/* log_2(1000000). */ 468#define LOG2_1M 20 469 470/* 471 * Convert the elements of a timeval into a 32-bit word holding 472 * the bits of a IEEE-754 float. 473 * The float value represents the timeval's value in microsecond units. 474 */ 475static uint32_t 476encode_timeval(struct timeval tv) 477{ 478 int log2_s; 479 int val, exp; /* Unnormalized value and exponent */ 480 int norm_exp; /* Normalized exponent */ 481 int shift; 482 483 /* 484 * First calculate value and exponent to about CALC_BITS precision. 485 * Note that the following conditionals have been ordered so that 486 * the most common cases appear first. 487 */ 488 if (tv.tv_sec == 0) { 489 if (tv.tv_usec == 0) 490 return (0); 491 exp = 0; 492 val = tv.tv_usec; 493 } else { 494 /* 495 * Calculate the value to a precision of approximately 496 * CALC_BITS. 497 */ 498 log2_s = fls(tv.tv_sec) - 1; 499 if (log2_s + LOG2_1M < CALC_BITS) { 500 exp = 0; 501 val = 1000000 * tv.tv_sec + tv.tv_usec; 502 } else { 503 exp = log2_s + LOG2_1M - CALC_BITS; 504 val = (unsigned int)(((uint64_t)1000000 * tv.tv_sec + 505 tv.tv_usec) >> exp); 506 } 507 } 508 /* Now normalize and pack the value into an IEEE-754 float. */ 509 norm_exp = fls(val) - 1; 510 shift = FLT_MANT_DIG - norm_exp - 1; 511#ifdef ACCT_DEBUG 512 printf("val=%d exp=%d shift=%d log2(val)=%d\n", 513 val, exp, shift, norm_exp); 514 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 515 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 516#endif 517 return (((FLT_MAX_EXP - 1 + exp + norm_exp) << (FLT_MANT_DIG - 1)) | 518 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 519} 520 521/* 522 * Convert a non-negative long value into the bit pattern of 523 * an IEEE-754 float value. 524 */ 525static uint32_t 526encode_long(long val) 527{ 528 int norm_exp; /* Normalized exponent */ 529 int shift; 530 531 if (val == 0) 532 return (0); 533 if (val < 0) { 534 log(LOG_NOTICE, 535 "encode_long: negative value %ld in accounting record\n", 536 val); 537 val = LONG_MAX; 538 } 539 norm_exp = fls(val) - 1; 540 shift = FLT_MANT_DIG - norm_exp - 1; 541#ifdef ACCT_DEBUG 542 printf("val=%d shift=%d log2(val)=%d\n", 543 val, shift, norm_exp); 544 printf("exp=%x mant=%x\n", FLT_MAX_EXP - 1 + exp + norm_exp, 545 ((shift > 0 ? (val << shift) : (val >> -shift)) & MANT_MASK)); 546#endif 547 return (((FLT_MAX_EXP - 1 + norm_exp) << (FLT_MANT_DIG - 1)) | 548 ((shift > 0 ? val << shift : val >> -shift) & MANT_MASK)); 549} 550 551/* FLOAT_CONVERSION_END (Regression testing; don't remove this line.) */ 552 553/* 554 * Periodically check the filesystem to see if accounting 555 * should be turned on or off. Beware the case where the vnode 556 * has been vgone()'d out from underneath us, e.g. when the file 557 * system containing the accounting file has been forcibly unmounted. 558 */ 559/* ARGSUSED */ 560static void 561acctwatch(void) 562{ 563 struct statfs *sp; 564 565 sx_assert(&acct_sx, SX_XLOCKED); 566 567 /* 568 * If accounting was disabled before our kthread was scheduled, 569 * then acct_vp might be NULL. If so, just ask our kthread to 570 * exit and return. 571 */ 572 if (acct_vp == NULL) { 573 acct_state |= ACCT_EXITREQ; 574 return; 575 } 576 577 /* 578 * If our vnode is no longer valid, tear it down and signal the 579 * accounting thread to die. 580 */ 581 if (acct_vp->v_type == VBAD) { 582 (void) acct_disable(NULL, 1); 583 acct_state |= ACCT_EXITREQ; 584 return; 585 } 586 587 /* 588 * Stopping here is better than continuing, maybe it will be VBAD 589 * next time around. 590 */ 591 sp = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK); 592 if (VFS_STATFS(acct_vp->v_mount, sp) < 0) { 593 free(sp, M_STATFS); 594 return; 595 } 596 if (acct_suspended) { 597 if (sp->f_bavail > (int64_t)(acctresume * sp->f_blocks / 598 100)) { 599 acct_suspended = 0; 600 log(LOG_NOTICE, "Accounting resumed\n"); 601 } 602 } else { 603 if (sp->f_bavail <= (int64_t)(acctsuspend * sp->f_blocks / 604 100)) { 605 acct_suspended = 1; 606 log(LOG_NOTICE, "Accounting suspended\n"); 607 } 608 } 609 free(sp, M_STATFS); 610} 611 612/* 613 * The main loop for the dedicated kernel thread that periodically calls 614 * acctwatch(). 615 */ 616static void 617acct_thread(void *dummy) 618{ 619 u_char pri; 620 621 /* This is a low-priority kernel thread. */ 622 pri = PRI_MAX_KERN; 623 thread_lock(curthread); 624 sched_prio(curthread, pri); 625 thread_unlock(curthread); 626 627 /* If another accounting kthread is already running, just die. */ 628 sx_xlock(&acct_sx); 629 if (acct_state & ACCT_RUNNING) { 630 sx_xunlock(&acct_sx); 631 kproc_exit(0); 632 } 633 acct_state |= ACCT_RUNNING; 634 635 /* Loop until we are asked to exit. */ 636 while (!(acct_state & ACCT_EXITREQ)) { 637 638 /* Perform our periodic checks. */ 639 acctwatch(); 640 641 /* 642 * We check this flag again before sleeping since the 643 * acctwatch() might have shut down accounting and asked us 644 * to exit. 645 */ 646 if (!(acct_state & ACCT_EXITREQ)) { 647 sx_sleep(&acct_state, &acct_sx, 0, "-", 648 acctchkfreq * hz); 649 } 650 } 651 652 /* 653 * Acknowledge the exit request and shutdown. We clear both the 654 * exit request and running flags. 655 */ 656 acct_state = 0; 657 sx_xunlock(&acct_sx); 658 kproc_exit(0); 659} 660