FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_acct.c
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: releng/8.3/sys/kern/kern_acct.c 199583 2009-11-20 15:27:52Z jhb $");
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/mount.h>
82 #include <sys/mutex.h>
83 #include <sys/namei.h>
84 #include <sys/priv.h>
85 #include <sys/proc.h>
86 #include <sys/resourcevar.h>
87 #include <sys/sched.h>
88 #include <sys/sx.h>
89 #include <sys/sysctl.h>
90 #include <sys/sysent.h>
91 #include <sys/syslog.h>
92 #include <sys/sysproto.h>
93 #include <sys/tty.h>
94 #include <sys/vnode.h>
95
96 #include <security/mac/mac_framework.h>
97
98 /*
99 * The routines implemented in this file are described in:
100 * Leffler, et al.: The Design and Implementation of the 4.3BSD
101 * UNIX Operating System (Addison Welley, 1989)
102 * on pages 62-63.
103 * On May 2007 the historic 3 bits base 8 exponent, 13 bit fraction
104 * compt_t representation described in the above reference was replaced
105 * with that of IEEE-754 floats.
106 *
107 * Arguably, to simplify accounting operations, this mechanism should
108 * be replaced by one in which an accounting log file (similar to /dev/klog)
109 * is read by a user process, etc. However, that has its own problems.
110 */
111
112 /* Floating point definitions from <float.h>. */
113 #define FLT_MANT_DIG 24 /* p */
114 #define FLT_MAX_EXP 128 /* emax */
115
116 /*
117 * Internal accounting functions.
118 * The former's operation is described in Leffler, et al., and the latter
119 * was provided by UCB with the 4.4BSD-Lite release
120 */
121 static uint32_t encode_timeval(struct timeval);
122 static uint32_t encode_long(long);
123 static void acctwatch(void);
124 static void acct_thread(void *);
125 static int acct_disable(struct thread *);
126
127 /*
128 * Accounting vnode pointer, saved vnode pointer, and flags for each.
129 * acct_sx protects against changes to the active vnode and credentials
130 * while accounting records are being committed to disk.
131 */
132 static int acct_configured;
133 static int acct_suspended;
134 static struct vnode *acct_vp;
135 static struct ucred *acct_cred;
136 static int acct_flags;
137 static struct sx acct_sx;
138
139 SX_SYSINIT(acct, &acct_sx, "acct_sx");
140
141 /*
142 * State of the accounting kthread.
143 */
144 static int acct_state;
145
146 #define ACCT_RUNNING 1 /* Accounting kthread is running. */
147 #define ACCT_EXITREQ 2 /* Accounting kthread should exit. */
148
149 /*
150 * Values associated with enabling and disabling accounting
151 */
152 static int acctsuspend = 2; /* stop accounting when < 2% free space left */
153 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
154 &acctsuspend, 0, "percentage of free disk space below which accounting stops");
155
156 static int acctresume = 4; /* resume when free space risen to > 4% */
157 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
158 &acctresume, 0, "percentage of free disk space above which accounting resumes");
159
160 static int acctchkfreq = 15; /* frequency (in seconds) to check space */
161
162 static int
163 sysctl_acct_chkfreq(SYSCTL_HANDLER_ARGS)
164 {
165 int error, value;
166
167 /* Write out the old value. */
168 error = SYSCTL_OUT(req, &acctchkfreq, sizeof(int));
169 if (error || req->newptr == NULL)
170 return (error);
171
172 /* Read in and verify the new value. */
173 error = SYSCTL_IN(req, &value, sizeof(int));
174 if (error)
175 return (error);
176 if (value <= 0)
177 return (EINVAL);
178 acctchkfreq = value;
179 return (0);
180 }
181 SYSCTL_PROC(_kern, OID_AUTO, acct_chkfreq, CTLTYPE_INT|CTLFLAG_RW,
182 &acctchkfreq, 0, sysctl_acct_chkfreq, "I",
183 "frequency for checking the free space");
184
185 SYSCTL_INT(_kern, OID_AUTO, acct_configured, CTLFLAG_RD, &acct_configured, 0,
186 "Accounting configured or not");
187
188 SYSCTL_INT(_kern, OID_AUTO, acct_suspended, CTLFLAG_RD, &acct_suspended, 0,
189 "Accounting suspended or not");
190
191 /*
192 * Accounting system call. Written based on the specification and previous
193 * implementation done by Mark Tinguely.
194 */
195 int
196 acct(struct thread *td, struct acct_args *uap)
197 {
198 struct nameidata nd;
199 int error, flags, vfslocked;
200
201 error = priv_check(td, PRIV_ACCT);
202 if (error)
203 return (error);
204
205 /*
206 * If accounting is to be started to a file, open that file for
207 * appending and make sure it's a 'normal'.
208 */
209 if (uap->path != NULL) {
210 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE | AUDITVNODE1,
211 UIO_USERSPACE, uap->path, td);
212 flags = FWRITE | O_APPEND;
213 error = vn_open(&nd, &flags, 0, NULL);
214 if (error)
215 return (error);
216 vfslocked = NDHASGIANT(&nd);
217 NDFREE(&nd, NDF_ONLY_PNBUF);
218 #ifdef MAC
219 error = mac_system_check_acct(td->td_ucred, nd.ni_vp);
220 if (error) {
221 VOP_UNLOCK(nd.ni_vp, 0);
222 vn_close(nd.ni_vp, flags, td->td_ucred, td);
223 VFS_UNLOCK_GIANT(vfslocked);
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 VFS_UNLOCK_GIANT(vfslocked);
231 return (EACCES);
232 }
233 VFS_UNLOCK_GIANT(vfslocked);
234 #ifdef MAC
235 } else {
236 error = mac_system_check_acct(td->td_ucred, NULL);
237 if (error)
238 return (error);
239 #endif
240 }
241
242 /*
243 * Disallow concurrent access to the accounting vnode while we swap
244 * it out, in order to prevent access after close.
245 */
246 sx_xlock(&acct_sx);
247
248 /*
249 * If accounting was previously enabled, kill the old space-watcher,
250 * close the file, and (if no new file was specified, leave). Reset
251 * the suspended state regardless of whether accounting remains
252 * enabled.
253 */
254 acct_suspended = 0;
255 if (acct_vp != NULL) {
256 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount);
257 error = acct_disable(td);
258 VFS_UNLOCK_GIANT(vfslocked);
259 }
260 if (uap->path == NULL) {
261 if (acct_state & ACCT_RUNNING) {
262 acct_state |= ACCT_EXITREQ;
263 wakeup(&acct_state);
264 }
265 sx_xunlock(&acct_sx);
266 return (error);
267 }
268
269 /*
270 * Save the new accounting file vnode, and schedule the new
271 * free space watcher.
272 */
273 acct_vp = nd.ni_vp;
274 acct_cred = crhold(td->td_ucred);
275 acct_flags = flags;
276 if (acct_state & ACCT_RUNNING)
277 acct_state &= ~ACCT_EXITREQ;
278 else {
279 /*
280 * Try to start up an accounting kthread. We may start more
281 * than one, but if so the extras will commit suicide as
282 * soon as they start up.
283 */
284 error = kproc_create(acct_thread, NULL, NULL, 0, 0,
285 "accounting");
286 if (error) {
287 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount);
288 (void) vn_close(acct_vp, acct_flags, acct_cred, td);
289 VFS_UNLOCK_GIANT(vfslocked);
290 crfree(acct_cred);
291 acct_configured = 0;
292 acct_vp = NULL;
293 acct_cred = NULL;
294 acct_flags = 0;
295 sx_xunlock(&acct_sx);
296 log(LOG_NOTICE, "Unable to start accounting thread\n");
297 return (error);
298 }
299 }
300 acct_configured = 1;
301 sx_xunlock(&acct_sx);
302 log(LOG_NOTICE, "Accounting enabled\n");
303 return (error);
304 }
305
306 /*
307 * Disable currently in-progress accounting by closing the vnode, dropping
308 * our reference to the credential, and clearing the vnode's flags.
309 */
310 static int
311 acct_disable(struct thread *td)
312 {
313 int error;
314
315 sx_assert(&acct_sx, SX_XLOCKED);
316 error = vn_close(acct_vp, acct_flags, acct_cred, td);
317 crfree(acct_cred);
318 acct_configured = 0;
319 acct_vp = NULL;
320 acct_cred = NULL;
321 acct_flags = 0;
322 log(LOG_NOTICE, "Accounting disabled\n");
323 return (error);
324 }
325
326 /*
327 * Write out process accounting information, on process exit.
328 * Data to be written out is specified in Leffler, et al.
329 * and are enumerated below. (They're also noted in the system
330 * "acct.h" header file.)
331 */
332 int
333 acct_process(struct thread *td)
334 {
335 struct acctv2 acct;
336 struct timeval ut, st, tmp;
337 struct plimit *newlim, *oldlim;
338 struct proc *p;
339 struct rusage ru;
340 int t, ret, vfslocked;
341
342 /*
343 * Lockless check of accounting condition before doing the hard
344 * work.
345 */
346 if (acct_vp == NULL || acct_suspended)
347 return (0);
348
349 sx_slock(&acct_sx);
350
351 /*
352 * If accounting isn't enabled, don't bother. Have to check again
353 * once we own the lock in case we raced with disabling of accounting
354 * by another thread.
355 */
356 if (acct_vp == NULL || acct_suspended) {
357 sx_sunlock(&acct_sx);
358 return (0);
359 }
360
361 p = td->td_proc;
362
363 /*
364 * Get process accounting information.
365 */
366
367 sx_slock(&proctree_lock);
368 PROC_LOCK(p);
369
370 /* (1) The terminal from which the process was started */
371 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
372 acct.ac_tty = tty_udev(p->p_pgrp->pg_session->s_ttyp);
373 else
374 acct.ac_tty = NODEV;
375 sx_sunlock(&proctree_lock);
376
377 /* (2) The name of the command that ran */
378 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
379
380 /* (3) The amount of user and system time that was used */
381 rufetchcalc(p, &ru, &ut, &st);
382 acct.ac_utime = encode_timeval(ut);
383 acct.ac_stime = encode_timeval(st);
384
385 /* (4) The elapsed time the command ran (and its starting time) */
386 tmp = boottime;
387 timevaladd(&tmp, &p->p_stats->p_start);
388 acct.ac_btime = tmp.tv_sec;
389 microuptime(&tmp);
390 timevalsub(&tmp, &p->p_stats->p_start);
391 acct.ac_etime = encode_timeval(tmp);
392
393 /* (5) The average amount of memory used */
394 tmp = ut;
395 timevaladd(&tmp, &st);
396 /* Convert tmp (i.e. u + s) into hz units to match ru_i*. */
397 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
398 if (t)
399 acct.ac_mem = encode_long((ru.ru_ixrss + ru.ru_idrss +
400 + ru.ru_isrss) / t);
401 else
402 acct.ac_mem = 0;
403
404 /* (6) The number of disk I/O operations done */
405 acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock);
406
407 /* (7) The UID and GID of the process */
408 acct.ac_uid = p->p_ucred->cr_ruid;
409 acct.ac_gid = p->p_ucred->cr_rgid;
410
411 /* (8) The boolean flags that tell how the process terminated, etc. */
412 acct.ac_flagx = p->p_acflag;
413 PROC_UNLOCK(p);
414
415 /* Setup ancillary structure fields. */
416 acct.ac_flagx |= ANVER;
417 acct.ac_zero = 0;
418 acct.ac_version = 2;
419 acct.ac_len = acct.ac_len2 = sizeof(acct);
420
421 /*
422 * Eliminate any file size rlimit.
423 */
424 newlim = lim_alloc();
425 PROC_LOCK(p);
426 oldlim = p->p_limit;
427 lim_copy(newlim, oldlim);
428 newlim->pl_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
429 p->p_limit = newlim;
430 PROC_UNLOCK(p);
431 lim_free(oldlim);
432
433 /*
434 * Write the accounting information to the file.
435 */
436 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount);
437 ret = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct, sizeof (acct),
438 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NOCRED,
439 NULL, td);
440 VFS_UNLOCK_GIANT(vfslocked);
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)(((u_int64_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 sb;
557 int vfslocked;
558
559 sx_assert(&acct_sx, SX_XLOCKED);
560
561 /*
562 * If accounting was disabled before our kthread was scheduled,
563 * then acct_vp might be NULL. If so, just ask our kthread to
564 * exit and return.
565 */
566 if (acct_vp == NULL) {
567 acct_state |= ACCT_EXITREQ;
568 return;
569 }
570
571 /*
572 * If our vnode is no longer valid, tear it down and signal the
573 * accounting thread to die.
574 */
575 vfslocked = VFS_LOCK_GIANT(acct_vp->v_mount);
576 if (acct_vp->v_type == VBAD) {
577 (void) acct_disable(NULL);
578 VFS_UNLOCK_GIANT(vfslocked);
579 acct_state |= ACCT_EXITREQ;
580 return;
581 }
582
583 /*
584 * Stopping here is better than continuing, maybe it will be VBAD
585 * next time around.
586 */
587 if (VFS_STATFS(acct_vp->v_mount, &sb) < 0) {
588 VFS_UNLOCK_GIANT(vfslocked);
589 return;
590 }
591 VFS_UNLOCK_GIANT(vfslocked);
592 if (acct_suspended) {
593 if (sb.f_bavail > (int64_t)(acctresume * sb.f_blocks /
594 100)) {
595 acct_suspended = 0;
596 log(LOG_NOTICE, "Accounting resumed\n");
597 }
598 } else {
599 if (sb.f_bavail <= (int64_t)(acctsuspend * sb.f_blocks /
600 100)) {
601 acct_suspended = 1;
602 log(LOG_NOTICE, "Accounting suspended\n");
603 }
604 }
605 }
606
607 /*
608 * The main loop for the dedicated kernel thread that periodically calls
609 * acctwatch().
610 */
611 static void
612 acct_thread(void *dummy)
613 {
614 u_char pri;
615
616 /* This is a low-priority kernel thread. */
617 pri = PRI_MAX_KERN;
618 thread_lock(curthread);
619 sched_prio(curthread, pri);
620 thread_unlock(curthread);
621
622 /* If another accounting kthread is already running, just die. */
623 sx_xlock(&acct_sx);
624 if (acct_state & ACCT_RUNNING) {
625 sx_xunlock(&acct_sx);
626 kproc_exit(0);
627 }
628 acct_state |= ACCT_RUNNING;
629
630 /* Loop until we are asked to exit. */
631 while (!(acct_state & ACCT_EXITREQ)) {
632
633 /* Perform our periodic checks. */
634 acctwatch();
635
636 /*
637 * We check this flag again before sleeping since the
638 * acctwatch() might have shut down accounting and asked us
639 * to exit.
640 */
641 if (!(acct_state & ACCT_EXITREQ)) {
642 sx_sleep(&acct_state, &acct_sx, 0, "-",
643 acctchkfreq * hz);
644 }
645 }
646
647 /*
648 * Acknowledge the exit request and shutdown. We clear both the
649 * exit request and running flags.
650 */
651 acct_state = 0;
652 sx_xunlock(&acct_sx);
653 kproc_exit(0);
654 }
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