1/*-
2 * Copyright (c) 1994 Christopher G. Demetriou
3 * Copyright (c) 1982, 1986, 1989, 1993
4 * The Regents of the University of California. All rights reserved.
5 * (c) UNIX System Laboratories, Inc.
6 * All or some portions of this file are derived from material licensed
7 * to the University of California by American Telephone and Telegraph
8 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
9 * the permission of UNIX System Laboratories, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. 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 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
| 1/*-
2 * Copyright (c) 1994 Christopher G. Demetriou
3 * Copyright (c) 1982, 1986, 1989, 1993
4 * The Regents of the University of California. All rights reserved.
5 * (c) UNIX System Laboratories, Inc.
6 * All or some portions of this file are derived from material licensed
7 * to the University of California by American Telephone and Telegraph
8 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
9 * the permission of UNIX System Laboratories, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. 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 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
|
40 * $FreeBSD: head/sys/kern/kern_acct.c 85844 2001-11-01 20:56:57Z rwatson $
| 40 * $FreeBSD: head/sys/kern/kern_acct.c 91140 2002-02-23 11:12:57Z tanimura $
|
41 */
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/lock.h>
46#include <sys/mutex.h>
47#include <sys/sysproto.h>
48#include <sys/proc.h>
49#include <sys/mount.h>
50#include <sys/vnode.h>
51#include <sys/fcntl.h>
52#include <sys/syslog.h>
53#include <sys/kernel.h>
54#include <sys/sysent.h>
55#include <sys/sysctl.h>
56#include <sys/namei.h>
57#include <sys/acct.h>
58#include <sys/resourcevar.h>
59#include <sys/tty.h>
60
61/*
62 * The routines implemented in this file are described in:
63 * Leffler, et al.: The Design and Implementation of the 4.3BSD
64 * UNIX Operating System (Addison Welley, 1989)
65 * on pages 62-63.
66 *
67 * Arguably, to simplify accounting operations, this mechanism should
68 * be replaced by one in which an accounting log file (similar to /dev/klog)
69 * is read by a user process, etc. However, that has its own problems.
70 */
71
72/*
73 * Internal accounting functions.
74 * The former's operation is described in Leffler, et al., and the latter
75 * was provided by UCB with the 4.4BSD-Lite release
76 */
77static comp_t encode_comp_t __P((u_long, u_long));
78static void acctwatch __P((void *));
79
80/*
81 * Accounting callout used for periodic scheduling of acctwatch.
82 */
83static struct callout acctwatch_callout;
84
85/*
86 * Accounting vnode pointer, and saved vnode pointer.
87 */
88static struct vnode *acctp;
89static struct vnode *savacctp;
90
91/*
92 * Values associated with enabling and disabling accounting
93 */
94static int acctsuspend = 2; /* stop accounting when < 2% free space left */
95SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
96 &acctsuspend, 0, "percentage of free disk space below which accounting stops");
97
98static int acctresume = 4; /* resume when free space risen to > 4% */
99SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
100 &acctresume, 0, "percentage of free disk space above which accounting resumes");
101
102static int acctchkfreq = 15; /* frequency (in seconds) to check space */
103SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
104 &acctchkfreq, 0, "frequency for checking the free space");
105
106/*
107 * Accounting system call. Written based on the specification and
108 * previous implementation done by Mark Tinguely.
109 *
110 * MPSAFE
111 */
112int
113acct(td, uap)
114 struct thread *td;
115 struct acct_args /* {
116 syscallarg(char *) path;
117 } */ *uap;
118{
119 struct nameidata nd;
120 int error, flags;
121
122 mtx_lock(&Giant);
123 if (td != curthread)
124 panic("acct"); /* XXXKSE DIAGNOSTIC */
125 /* Make sure that the caller is root. */
126 error = suser_xxx(td->td_proc->p_ucred, NULL, 0);
127 if (error)
128 goto done2;
129
130 /*
131 * If accounting is to be started to a file, open that file for
132 * writing and make sure it's a 'normal'.
133 */
134 if (SCARG(uap, path) != NULL) {
135 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
136 td);
137 flags = FWRITE;
138 error = vn_open(&nd, &flags, 0);
139 if (error)
140 goto done2;
141 NDFREE(&nd, NDF_ONLY_PNBUF);
142 VOP_UNLOCK(nd.ni_vp, 0, td);
143 if (nd.ni_vp->v_type != VREG) {
144 vn_close(nd.ni_vp, FWRITE, td->td_proc->p_ucred, td);
145 error = EACCES;
146 goto done2;
147 }
148 }
149
150 /*
151 * If accounting was previously enabled, kill the old space-watcher,
152 * close the file, and (if no new file was specified, leave).
153 */
154 if (acctp != NULLVP || savacctp != NULLVP) {
155 callout_stop(&acctwatch_callout);
156 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE,
157 td->td_proc->p_ucred, td);
158 acctp = savacctp = NULLVP;
159 }
160 if (SCARG(uap, path) == NULL)
161 goto done2;
162
163 /*
164 * Save the new accounting file vnode, and schedule the new
165 * free space watcher.
166 */
167 acctp = nd.ni_vp;
168 callout_init(&acctwatch_callout, 0);
169 acctwatch(NULL);
170done2:
171 mtx_unlock(&Giant);
172 return (error);
173}
174
175/*
176 * Write out process accounting information, on process exit.
177 * Data to be written out is specified in Leffler, et al.
178 * and are enumerated below. (They're also noted in the system
179 * "acct.h" header file.)
180 */
181
182int
183acct_process(td)
184 struct thread *td;
185{
186 struct proc *p = td->td_proc;
187 struct acct acct;
188 struct rusage *r;
189 struct timeval ut, st, tmp;
190 int t;
191 struct vnode *vp;
192
193 /* If accounting isn't enabled, don't bother */
194 vp = acctp;
195 if (vp == NULLVP)
196 return (0);
197
198 /*
199 * Get process accounting information.
200 */
201
202 /* (1) The name of the command that ran */
203 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
204
205 /* (2) The amount of user and system time that was used */
206 mtx_lock_spin(&sched_lock);
207 calcru(p, &ut, &st, NULL);
208 mtx_unlock_spin(&sched_lock);
209 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
210 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
211
212 /* (3) The elapsed time the commmand ran (and its starting time) */
213 acct.ac_btime = p->p_stats->p_start.tv_sec;
214 microtime(&tmp);
215 timevalsub(&tmp, &p->p_stats->p_start);
216 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
217
218 /* (4) The average amount of memory used */
219 r = &p->p_stats->p_ru;
220 tmp = ut;
221 timevaladd(&tmp, &st);
222 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
223 if (t)
224 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
225 else
226 acct.ac_mem = 0;
227
228 /* (5) The number of disk I/O operations done */
229 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
230
231 /* (6) The UID and GID of the process */
232 acct.ac_uid = p->p_ucred->cr_ruid;
233 acct.ac_gid = p->p_ucred->cr_rgid;
234
235 /* (7) The terminal from which the process was started */
| 41 */
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/lock.h>
46#include <sys/mutex.h>
47#include <sys/sysproto.h>
48#include <sys/proc.h>
49#include <sys/mount.h>
50#include <sys/vnode.h>
51#include <sys/fcntl.h>
52#include <sys/syslog.h>
53#include <sys/kernel.h>
54#include <sys/sysent.h>
55#include <sys/sysctl.h>
56#include <sys/namei.h>
57#include <sys/acct.h>
58#include <sys/resourcevar.h>
59#include <sys/tty.h>
60
61/*
62 * The routines implemented in this file are described in:
63 * Leffler, et al.: The Design and Implementation of the 4.3BSD
64 * UNIX Operating System (Addison Welley, 1989)
65 * on pages 62-63.
66 *
67 * Arguably, to simplify accounting operations, this mechanism should
68 * be replaced by one in which an accounting log file (similar to /dev/klog)
69 * is read by a user process, etc. However, that has its own problems.
70 */
71
72/*
73 * Internal accounting functions.
74 * The former's operation is described in Leffler, et al., and the latter
75 * was provided by UCB with the 4.4BSD-Lite release
76 */
77static comp_t encode_comp_t __P((u_long, u_long));
78static void acctwatch __P((void *));
79
80/*
81 * Accounting callout used for periodic scheduling of acctwatch.
82 */
83static struct callout acctwatch_callout;
84
85/*
86 * Accounting vnode pointer, and saved vnode pointer.
87 */
88static struct vnode *acctp;
89static struct vnode *savacctp;
90
91/*
92 * Values associated with enabling and disabling accounting
93 */
94static int acctsuspend = 2; /* stop accounting when < 2% free space left */
95SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
96 &acctsuspend, 0, "percentage of free disk space below which accounting stops");
97
98static int acctresume = 4; /* resume when free space risen to > 4% */
99SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
100 &acctresume, 0, "percentage of free disk space above which accounting resumes");
101
102static int acctchkfreq = 15; /* frequency (in seconds) to check space */
103SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
104 &acctchkfreq, 0, "frequency for checking the free space");
105
106/*
107 * Accounting system call. Written based on the specification and
108 * previous implementation done by Mark Tinguely.
109 *
110 * MPSAFE
111 */
112int
113acct(td, uap)
114 struct thread *td;
115 struct acct_args /* {
116 syscallarg(char *) path;
117 } */ *uap;
118{
119 struct nameidata nd;
120 int error, flags;
121
122 mtx_lock(&Giant);
123 if (td != curthread)
124 panic("acct"); /* XXXKSE DIAGNOSTIC */
125 /* Make sure that the caller is root. */
126 error = suser_xxx(td->td_proc->p_ucred, NULL, 0);
127 if (error)
128 goto done2;
129
130 /*
131 * If accounting is to be started to a file, open that file for
132 * writing and make sure it's a 'normal'.
133 */
134 if (SCARG(uap, path) != NULL) {
135 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
136 td);
137 flags = FWRITE;
138 error = vn_open(&nd, &flags, 0);
139 if (error)
140 goto done2;
141 NDFREE(&nd, NDF_ONLY_PNBUF);
142 VOP_UNLOCK(nd.ni_vp, 0, td);
143 if (nd.ni_vp->v_type != VREG) {
144 vn_close(nd.ni_vp, FWRITE, td->td_proc->p_ucred, td);
145 error = EACCES;
146 goto done2;
147 }
148 }
149
150 /*
151 * If accounting was previously enabled, kill the old space-watcher,
152 * close the file, and (if no new file was specified, leave).
153 */
154 if (acctp != NULLVP || savacctp != NULLVP) {
155 callout_stop(&acctwatch_callout);
156 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE,
157 td->td_proc->p_ucred, td);
158 acctp = savacctp = NULLVP;
159 }
160 if (SCARG(uap, path) == NULL)
161 goto done2;
162
163 /*
164 * Save the new accounting file vnode, and schedule the new
165 * free space watcher.
166 */
167 acctp = nd.ni_vp;
168 callout_init(&acctwatch_callout, 0);
169 acctwatch(NULL);
170done2:
171 mtx_unlock(&Giant);
172 return (error);
173}
174
175/*
176 * Write out process accounting information, on process exit.
177 * Data to be written out is specified in Leffler, et al.
178 * and are enumerated below. (They're also noted in the system
179 * "acct.h" header file.)
180 */
181
182int
183acct_process(td)
184 struct thread *td;
185{
186 struct proc *p = td->td_proc;
187 struct acct acct;
188 struct rusage *r;
189 struct timeval ut, st, tmp;
190 int t;
191 struct vnode *vp;
192
193 /* If accounting isn't enabled, don't bother */
194 vp = acctp;
195 if (vp == NULLVP)
196 return (0);
197
198 /*
199 * Get process accounting information.
200 */
201
202 /* (1) The name of the command that ran */
203 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
204
205 /* (2) The amount of user and system time that was used */
206 mtx_lock_spin(&sched_lock);
207 calcru(p, &ut, &st, NULL);
208 mtx_unlock_spin(&sched_lock);
209 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
210 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
211
212 /* (3) The elapsed time the commmand ran (and its starting time) */
213 acct.ac_btime = p->p_stats->p_start.tv_sec;
214 microtime(&tmp);
215 timevalsub(&tmp, &p->p_stats->p_start);
216 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
217
218 /* (4) The average amount of memory used */
219 r = &p->p_stats->p_ru;
220 tmp = ut;
221 timevaladd(&tmp, &st);
222 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
223 if (t)
224 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
225 else
226 acct.ac_mem = 0;
227
228 /* (5) The number of disk I/O operations done */
229 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
230
231 /* (6) The UID and GID of the process */
232 acct.ac_uid = p->p_ucred->cr_ruid;
233 acct.ac_gid = p->p_ucred->cr_rgid;
234
235 /* (7) The terminal from which the process was started */
|
| 236 PROC_LOCK(p);
237 SESS_LOCK(p->p_session);
|
236 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
237 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
238 else
239 acct.ac_tty = NOUDEV;
| 238 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
239 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
240 else
241 acct.ac_tty = NOUDEV;
|
| 242 SESS_UNLOCK(p->p_session);
243 PROC_UNLOCK(p);
|
240
241 /* (8) The boolean flags that tell how the process terminated, etc. */
242 acct.ac_flag = p->p_acflag;
243
244 /*
245 * Eliminate any file size rlimit.
246 */
247 if (p->p_limit->p_refcnt > 1 &&
248 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) {
249 p->p_limit->p_refcnt--;
250 p->p_limit = limcopy(p->p_limit);
251 }
252 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
253
254 /*
255 * Write the accounting information to the file.
256 */
257 VOP_LEASE(vp, td, td->td_proc->p_ucred, LEASE_WRITE);
258 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
259 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, td->td_proc->p_ucred,
260 (int *)0, td));
261}
262
263/*
264 * Encode_comp_t converts from ticks in seconds and microseconds
265 * to ticks in 1/AHZ seconds. The encoding is described in
266 * Leffler, et al., on page 63.
267 */
268
269#define MANTSIZE 13 /* 13 bit mantissa. */
270#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
271#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
272
273static comp_t
274encode_comp_t(s, us)
275 u_long s, us;
276{
277 int exp, rnd;
278
279 exp = 0;
280 rnd = 0;
281 s *= AHZ;
282 s += us / (1000000 / AHZ); /* Maximize precision. */
283
284 while (s > MAXFRACT) {
285 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
286 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
287 exp++;
288 }
289
290 /* If we need to round up, do it (and handle overflow correctly). */
291 if (rnd && (++s > MAXFRACT)) {
292 s >>= EXPSIZE;
293 exp++;
294 }
295
296 /* Clean it up and polish it off. */
297 exp <<= MANTSIZE; /* Shift the exponent into place */
298 exp += s; /* and add on the mantissa. */
299 return (exp);
300}
301
302/*
303 * Periodically check the file system to see if accounting
304 * should be turned on or off. Beware the case where the vnode
305 * has been vgone()'d out from underneath us, e.g. when the file
306 * system containing the accounting file has been forcibly unmounted.
307 */
308/* ARGSUSED */
309static void
310acctwatch(a)
311 void *a;
312{
313 struct statfs sb;
314
315 if (savacctp != NULLVP) {
316 if (savacctp->v_type == VBAD) {
317 (void) vn_close(savacctp, FWRITE, NOCRED, NULL);
318 savacctp = NULLVP;
319 return;
320 }
321 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0);
322 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
323 acctp = savacctp;
324 savacctp = NULLVP;
325 log(LOG_NOTICE, "Accounting resumed\n");
326 }
327 } else {
328 if (acctp == NULLVP)
329 return;
330 if (acctp->v_type == VBAD) {
331 (void) vn_close(acctp, FWRITE, NOCRED, NULL);
332 acctp = NULLVP;
333 return;
334 }
335 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0);
336 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
337 savacctp = acctp;
338 acctp = NULLVP;
339 log(LOG_NOTICE, "Accounting suspended\n");
340 }
341 }
342 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL);
343}
| 244
245 /* (8) The boolean flags that tell how the process terminated, etc. */
246 acct.ac_flag = p->p_acflag;
247
248 /*
249 * Eliminate any file size rlimit.
250 */
251 if (p->p_limit->p_refcnt > 1 &&
252 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) {
253 p->p_limit->p_refcnt--;
254 p->p_limit = limcopy(p->p_limit);
255 }
256 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
257
258 /*
259 * Write the accounting information to the file.
260 */
261 VOP_LEASE(vp, td, td->td_proc->p_ucred, LEASE_WRITE);
262 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
263 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, td->td_proc->p_ucred,
264 (int *)0, td));
265}
266
267/*
268 * Encode_comp_t converts from ticks in seconds and microseconds
269 * to ticks in 1/AHZ seconds. The encoding is described in
270 * Leffler, et al., on page 63.
271 */
272
273#define MANTSIZE 13 /* 13 bit mantissa. */
274#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
275#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
276
277static comp_t
278encode_comp_t(s, us)
279 u_long s, us;
280{
281 int exp, rnd;
282
283 exp = 0;
284 rnd = 0;
285 s *= AHZ;
286 s += us / (1000000 / AHZ); /* Maximize precision. */
287
288 while (s > MAXFRACT) {
289 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
290 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
291 exp++;
292 }
293
294 /* If we need to round up, do it (and handle overflow correctly). */
295 if (rnd && (++s > MAXFRACT)) {
296 s >>= EXPSIZE;
297 exp++;
298 }
299
300 /* Clean it up and polish it off. */
301 exp <<= MANTSIZE; /* Shift the exponent into place */
302 exp += s; /* and add on the mantissa. */
303 return (exp);
304}
305
306/*
307 * Periodically check the file system to see if accounting
308 * should be turned on or off. Beware the case where the vnode
309 * has been vgone()'d out from underneath us, e.g. when the file
310 * system containing the accounting file has been forcibly unmounted.
311 */
312/* ARGSUSED */
313static void
314acctwatch(a)
315 void *a;
316{
317 struct statfs sb;
318
319 if (savacctp != NULLVP) {
320 if (savacctp->v_type == VBAD) {
321 (void) vn_close(savacctp, FWRITE, NOCRED, NULL);
322 savacctp = NULLVP;
323 return;
324 }
325 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0);
326 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
327 acctp = savacctp;
328 savacctp = NULLVP;
329 log(LOG_NOTICE, "Accounting resumed\n");
330 }
331 } else {
332 if (acctp == NULLVP)
333 return;
334 if (acctp->v_type == VBAD) {
335 (void) vn_close(acctp, FWRITE, NOCRED, NULL);
336 acctp = NULLVP;
337 return;
338 }
339 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0);
340 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
341 savacctp = acctp;
342 acctp = NULLVP;
343 log(LOG_NOTICE, "Accounting suspended\n");
344 }
345 }
346 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL);
347}
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