FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_acct.c
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: releng/5.1/sys/kern/kern_acct.c 114434 2003-05-01 16:59:23Z des $
41 */
42
43 #include "opt_mac.h"
44
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/lock.h>
48 #include <sys/mutex.h>
49 #include <sys/sysproto.h>
50 #include <sys/proc.h>
51 #include <sys/mac.h>
52 #include <sys/mount.h>
53 #include <sys/vnode.h>
54 #include <sys/fcntl.h>
55 #include <sys/syslog.h>
56 #include <sys/kernel.h>
57 #include <sys/sysent.h>
58 #include <sys/sysctl.h>
59 #include <sys/namei.h>
60 #include <sys/acct.h>
61 #include <sys/resourcevar.h>
62 #include <sys/tty.h>
63
64 /*
65 * The routines implemented in this file are described in:
66 * Leffler, et al.: The Design and Implementation of the 4.3BSD
67 * UNIX Operating System (Addison Welley, 1989)
68 * on pages 62-63.
69 *
70 * Arguably, to simplify accounting operations, this mechanism should
71 * be replaced by one in which an accounting log file (similar to /dev/klog)
72 * is read by a user process, etc. However, that has its own problems.
73 */
74
75 /*
76 * Internal accounting functions.
77 * The former's operation is described in Leffler, et al., and the latter
78 * was provided by UCB with the 4.4BSD-Lite release
79 */
80 static comp_t encode_comp_t(u_long, u_long);
81 static void acctwatch(void *);
82
83 /*
84 * Accounting callout used for periodic scheduling of acctwatch.
85 */
86 static struct callout acctwatch_callout;
87
88 /*
89 * Accounting vnode pointer, saved vnode pointer, and flags for each.
90 */
91 static struct vnode *acctp;
92 static struct ucred *acctcred;
93 static int acctflags;
94 static struct vnode *savacctp;
95 static struct ucred *savacctcred;
96 static int savacctflags;
97
98 static struct mtx acct_mtx;
99 MTX_SYSINIT(acct, &acct_mtx, "accounting", MTX_DEF);
100
101 /*
102 * Values associated with enabling and disabling accounting
103 */
104 static int acctsuspend = 2; /* stop accounting when < 2% free space left */
105 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
106 &acctsuspend, 0, "percentage of free disk space below which accounting stops");
107
108 static int acctresume = 4; /* resume when free space risen to > 4% */
109 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
110 &acctresume, 0, "percentage of free disk space above which accounting resumes");
111
112 static int acctchkfreq = 15; /* frequency (in seconds) to check space */
113 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
114 &acctchkfreq, 0, "frequency for checking the free space");
115
116 /*
117 * Accounting system call. Written based on the specification and
118 * previous implementation done by Mark Tinguely.
119 *
120 * MPSAFE
121 */
122 int
123 acct(td, uap)
124 struct thread *td;
125 struct acct_args /* {
126 char *path;
127 } */ *uap;
128 {
129 struct nameidata nd;
130 int error, flags;
131
132 /* Make sure that the caller is root. */
133 error = suser(td);
134 if (error)
135 return (error);
136
137 mtx_lock(&Giant);
138 /*
139 * If accounting is to be started to a file, open that file for
140 * appending and make sure it's a 'normal'.
141 */
142 if (uap->path != NULL) {
143 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, td);
144 flags = FWRITE | O_APPEND;
145 error = vn_open(&nd, &flags, 0);
146 if (error)
147 goto done2;
148 NDFREE(&nd, NDF_ONLY_PNBUF);
149 #ifdef MAC
150 error = mac_check_system_acct(td->td_ucred, nd.ni_vp);
151 if (error) {
152 vn_close(nd.ni_vp, flags, td->td_ucred, td);
153 goto done2;
154 }
155 #endif
156 VOP_UNLOCK(nd.ni_vp, 0, td);
157 if (nd.ni_vp->v_type != VREG) {
158 vn_close(nd.ni_vp, flags, td->td_ucred, td);
159 error = EACCES;
160 goto done2;
161 }
162 #ifdef MAC
163 } else {
164 error = mac_check_system_acct(td->td_ucred, NULL);
165 if (error)
166 goto done2;
167 #endif
168 }
169
170 /*
171 * If accounting was previously enabled, kill the old space-watcher,
172 * close the file, and (if no new file was specified, leave).
173 */
174
175 /*
176 * XXX arr: Should not hold lock over vnode operation.
177 */
178
179 mtx_lock(&acct_mtx);
180 if (acctp != NULLVP || savacctp != NULLVP) {
181 callout_stop(&acctwatch_callout);
182 error = vn_close((acctp != NULLVP ? acctp : savacctp),
183 (acctp != NULLVP ? acctflags : savacctflags),
184 (acctcred != NOCRED ? acctcred : savacctcred), td);
185 acctp = savacctp = NULLVP;
186 crfree(acctcred != NOCRED ? acctcred : savacctcred);
187 acctcred = savacctcred = NOCRED;
188 }
189 if (uap->path == NULL) {
190 mtx_unlock(&acct_mtx);
191 goto done2;
192 }
193
194 /*
195 * Save the new accounting file vnode, and schedule the new
196 * free space watcher.
197 */
198 acctp = nd.ni_vp;
199 acctcred = crhold(td->td_ucred);
200 acctflags = flags;
201 callout_init(&acctwatch_callout, 0);
202 mtx_unlock(&acct_mtx);
203 acctwatch(NULL);
204 done2:
205 mtx_unlock(&Giant);
206 return (error);
207 }
208
209 /*
210 * Write out process accounting information, on process exit.
211 * Data to be written out is specified in Leffler, et al.
212 * and are enumerated below. (They're also noted in the system
213 * "acct.h" header file.)
214 */
215
216 int
217 acct_process(td)
218 struct thread *td;
219 {
220 struct proc *p = td->td_proc;
221 struct acct acct;
222 struct rusage *r;
223 struct timeval ut, st, tmp;
224 int t, ret;
225 struct vnode *vp;
226 struct ucred *uc;
227
228 mtx_lock(&acct_mtx);
229
230 /* If accounting isn't enabled, don't bother */
231 vp = acctp;
232 if (vp == NULLVP) {
233 mtx_unlock(&acct_mtx);
234 return (0);
235 }
236
237 /*
238 * Get process accounting information.
239 */
240
241 PROC_LOCK(p);
242 /* (1) The name of the command that ran */
243 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
244
245 /* (2) The amount of user and system time that was used */
246 mtx_lock_spin(&sched_lock);
247 calcru(p, &ut, &st, NULL);
248 mtx_unlock_spin(&sched_lock);
249 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
250 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
251
252 /* (3) The elapsed time the command ran (and its starting time) */
253 tmp = boottime;
254 timevaladd(&tmp, &p->p_stats->p_start);
255 acct.ac_btime = tmp.tv_sec;
256 microuptime(&tmp);
257 timevalsub(&tmp, &p->p_stats->p_start);
258 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
259
260 /* (4) The average amount of memory used */
261 r = &p->p_stats->p_ru;
262 tmp = ut;
263 timevaladd(&tmp, &st);
264 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
265 if (t)
266 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
267 else
268 acct.ac_mem = 0;
269
270 /* (5) The number of disk I/O operations done */
271 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
272
273 /* (6) The UID and GID of the process */
274 acct.ac_uid = p->p_ucred->cr_ruid;
275 acct.ac_gid = p->p_ucred->cr_rgid;
276
277 /* (7) The terminal from which the process was started */
278 SESS_LOCK(p->p_session);
279 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
280 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
281 else
282 acct.ac_tty = NOUDEV;
283 SESS_UNLOCK(p->p_session);
284
285 /* (8) The boolean flags that tell how the process terminated, etc. */
286 acct.ac_flag = p->p_acflag;
287 PROC_UNLOCK(p);
288
289 /*
290 * Write the accounting information to the file.
291 */
292 uc = crhold(acctcred);
293 vref(vp);
294 mtx_unlock(&acct_mtx);
295
296 /*
297 * Eliminate any file size rlimit.
298 */
299 if (p->p_limit->p_refcnt > 1) {
300 p->p_limit->p_refcnt--;
301 p->p_limit = limcopy(p->p_limit);
302 }
303 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
304
305 VOP_LEASE(vp, td, uc, LEASE_WRITE);
306 ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
307 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, uc, NOCRED,
308 (int *)0, td);
309 vrele(vp);
310 crfree(uc);
311 return (ret);
312 }
313
314 /*
315 * Encode_comp_t converts from ticks in seconds and microseconds
316 * to ticks in 1/AHZ seconds. The encoding is described in
317 * Leffler, et al., on page 63.
318 */
319
320 #define MANTSIZE 13 /* 13 bit mantissa. */
321 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
322 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
323
324 static comp_t
325 encode_comp_t(s, us)
326 u_long s, us;
327 {
328 int exp, rnd;
329
330 exp = 0;
331 rnd = 0;
332 s *= AHZ;
333 s += us / (1000000 / AHZ); /* Maximize precision. */
334
335 while (s > MAXFRACT) {
336 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
337 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
338 exp++;
339 }
340
341 /* If we need to round up, do it (and handle overflow correctly). */
342 if (rnd && (++s > MAXFRACT)) {
343 s >>= EXPSIZE;
344 exp++;
345 }
346
347 /* Clean it up and polish it off. */
348 exp <<= MANTSIZE; /* Shift the exponent into place */
349 exp += s; /* and add on the mantissa. */
350 return (exp);
351 }
352
353 /*
354 * Periodically check the filesystem to see if accounting
355 * should be turned on or off. Beware the case where the vnode
356 * has been vgone()'d out from underneath us, e.g. when the file
357 * system containing the accounting file has been forcibly unmounted.
358 */
359 /* ARGSUSED */
360 static void
361 acctwatch(a)
362 void *a;
363 {
364 struct statfs sb;
365
366 mtx_lock(&acct_mtx);
367
368 /*
369 * XXX arr: Need to fix the issue of holding acct_mtx over
370 * the below vnode operations.
371 */
372
373 if (savacctp != NULLVP) {
374 if (savacctp->v_type == VBAD) {
375 (void) vn_close(savacctp, savacctflags, savacctcred,
376 NULL);
377 savacctp = NULLVP;
378 savacctcred = NOCRED;
379 mtx_unlock(&acct_mtx);
380 return;
381 }
382 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0);
383 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
384 acctp = savacctp;
385 acctcred = savacctcred;
386 acctflags = savacctflags;
387 savacctp = NULLVP;
388 savacctcred = NOCRED;
389 log(LOG_NOTICE, "Accounting resumed\n");
390 }
391 } else {
392 if (acctp == NULLVP) {
393 mtx_unlock(&acct_mtx);
394 return;
395 }
396 if (acctp->v_type == VBAD) {
397 (void) vn_close(acctp, acctflags, acctcred, NULL);
398 acctp = NULLVP;
399 crfree(acctcred);
400 acctcred = NOCRED;
401 mtx_unlock(&acct_mtx);
402 return;
403 }
404 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0);
405 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
406 savacctp = acctp;
407 savacctflags = acctflags;
408 savacctcred = acctcred;
409 acctp = NULLVP;
410 acctcred = NOCRED;
411 log(LOG_NOTICE, "Accounting suspended\n");
412 }
413 }
414 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL);
415 mtx_unlock(&acct_mtx);
416 }
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