FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_acct.c
1 /* $NetBSD: kern_acct.c,v 1.69 2006/11/01 10:17:58 yamt Exp $ */
2
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 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)kern_acct.c 8.8 (Berkeley) 5/14/95
37 */
38
39 /*-
40 * Copyright (c) 1994 Christopher G. Demetriou
41 *
42 * Redistribution and use in source and binary forms, with or without
43 * modification, are permitted provided that the following conditions
44 * are met:
45 * 1. Redistributions of source code must retain the above copyright
46 * notice, this list of conditions and the following disclaimer.
47 * 2. Redistributions in binary form must reproduce the above copyright
48 * notice, this list of conditions and the following disclaimer in the
49 * documentation and/or other materials provided with the distribution.
50 * 3. All advertising materials mentioning features or use of this software
51 * must display the following acknowledgement:
52 * This product includes software developed by the University of
53 * California, Berkeley and its contributors.
54 * 4. Neither the name of the University nor the names of its contributors
55 * may be used to endorse or promote products derived from this software
56 * without specific prior written permission.
57 *
58 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
59 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
60 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
61 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
62 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
63 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
64 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
65 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
66 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
67 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68 * SUCH DAMAGE.
69 *
70 * @(#)kern_acct.c 8.8 (Berkeley) 5/14/95
71 */
72
73 #include <sys/cdefs.h>
74 __KERNEL_RCSID(0, "$NetBSD: kern_acct.c,v 1.69 2006/11/01 10:17:58 yamt Exp $");
75
76 #include <sys/param.h>
77 #include <sys/systm.h>
78 #include <sys/proc.h>
79 #include <sys/mount.h>
80 #include <sys/vnode.h>
81 #include <sys/file.h>
82 #include <sys/syslog.h>
83 #include <sys/kernel.h>
84 #include <sys/kthread.h>
85 #include <sys/lock.h>
86 #include <sys/malloc.h>
87 #include <sys/namei.h>
88 #include <sys/errno.h>
89 #include <sys/acct.h>
90 #include <sys/resourcevar.h>
91 #include <sys/ioctl.h>
92 #include <sys/tty.h>
93 #include <sys/kauth.h>
94
95 #include <sys/sa.h>
96 #include <sys/syscallargs.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 *
104 * Arguably, to simplify accounting operations, this mechanism should
105 * be replaced by one in which an accounting log file (similar to /dev/klog)
106 * is read by a user process, etc. However, that has its own problems.
107 */
108
109 /*
110 * Lock to serialize system calls and kernel threads.
111 */
112 static struct lock acct_lock;
113 #define ACCT_LOCK() \
114 do { \
115 (void) lockmgr(&acct_lock, LK_EXCLUSIVE, NULL); \
116 } while (/* CONSTCOND */0)
117 #define ACCT_UNLOCK() \
118 do { \
119 (void) lockmgr(&acct_lock, LK_RELEASE, NULL); \
120 } while (/* CONSTCOND */0)
121
122 /*
123 * The global accounting state and related data. Gain the lock before
124 * accessing these variables.
125 */
126 static enum {
127 ACCT_STOP,
128 ACCT_ACTIVE,
129 ACCT_SUSPENDED
130 } acct_state; /* The current accounting state. */
131 static struct vnode *acct_vp; /* Accounting vnode pointer. */
132 static kauth_cred_t acct_cred; /* Credential of accounting file
133 owner (i.e root). Used when
134 accounting file i/o. */
135 static struct proc *acct_dkwatcher; /* Free disk space checker. */
136
137 /*
138 * Values associated with enabling and disabling accounting
139 */
140 int acctsuspend = 2; /* stop accounting when < 2% free space left */
141 int acctresume = 4; /* resume when free space risen to > 4% */
142 int acctchkfreq = 15; /* frequency (in seconds) to check space */
143
144 /*
145 * Encode_comp_t converts from ticks in seconds and microseconds
146 * to ticks in 1/AHZ seconds. The encoding is described in
147 * Leffler, et al., on page 63.
148 */
149
150 #define MANTSIZE 13 /* 13 bit mantissa. */
151 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
152 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
153
154 static comp_t
155 encode_comp_t(u_long s, u_long us)
156 {
157 int exp, rnd;
158
159 exp = 0;
160 rnd = 0;
161 s *= AHZ;
162 s += us / (1000000 / AHZ); /* Maximize precision. */
163
164 while (s > MAXFRACT) {
165 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
166 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
167 exp++;
168 }
169
170 /* If we need to round up, do it (and handle overflow correctly). */
171 if (rnd && (++s > MAXFRACT)) {
172 s >>= EXPSIZE;
173 exp++;
174 }
175
176 /* Clean it up and polish it off. */
177 exp <<= MANTSIZE; /* Shift the exponent into place */
178 exp += s; /* and add on the mantissa. */
179 return (exp);
180 }
181
182 static int
183 acct_chkfree(void)
184 {
185 int error;
186 struct statvfs *sb;
187 int64_t bavail;
188
189 sb = malloc(sizeof(*sb), M_TEMP, M_WAITOK);
190 error = VFS_STATVFS(acct_vp->v_mount, sb, NULL);
191 if (error != 0)
192 return (error);
193
194 bavail = sb->f_bfree - sb->f_bresvd;
195
196 switch (acct_state) {
197 case ACCT_SUSPENDED:
198 if (bavail > acctresume * sb->f_blocks / 100) {
199 acct_state = ACCT_ACTIVE;
200 log(LOG_NOTICE, "Accounting resumed\n");
201 }
202 break;
203 case ACCT_ACTIVE:
204 if (bavail <= acctsuspend * sb->f_blocks / 100) {
205 acct_state = ACCT_SUSPENDED;
206 log(LOG_NOTICE, "Accounting suspended\n");
207 }
208 break;
209 case ACCT_STOP:
210 break;
211 }
212 free(sb, M_TEMP);
213 return (0);
214 }
215
216 static void
217 acct_stop(void)
218 {
219 int error;
220
221 if (acct_vp != NULLVP && acct_vp->v_type != VBAD) {
222 error = vn_close(acct_vp, FWRITE, acct_cred, NULL);
223 #ifdef DIAGNOSTIC
224 if (error != 0)
225 printf("acct_stop: failed to close, errno = %d\n",
226 error);
227 #endif
228 acct_vp = NULLVP;
229 }
230 if (acct_cred != NULL) {
231 kauth_cred_free(acct_cred);
232 acct_cred = NULL;
233 }
234 acct_state = ACCT_STOP;
235 }
236
237 /*
238 * Periodically check the file system to see if accounting
239 * should be turned on or off. Beware the case where the vnode
240 * has been vgone()'d out from underneath us, e.g. when the file
241 * system containing the accounting file has been forcibly unmounted.
242 */
243 static void
244 acctwatch(void *arg)
245 {
246 int error;
247
248 log(LOG_NOTICE, "Accounting started\n");
249 ACCT_LOCK();
250 while (acct_state != ACCT_STOP) {
251 if (acct_vp->v_type == VBAD) {
252 log(LOG_NOTICE, "Accounting terminated\n");
253 acct_stop();
254 continue;
255 }
256
257 error = acct_chkfree();
258 #ifdef DIAGNOSTIC
259 if (error != 0)
260 printf("acctwatch: failed to statvfs, error = %d\n",
261 error);
262 #endif
263
264 ACCT_UNLOCK();
265 error = tsleep(acctwatch, PSWP, "actwat", acctchkfreq * hz);
266 ACCT_LOCK();
267 #ifdef DIAGNOSTIC
268 if (error != 0 && error != EWOULDBLOCK)
269 printf("acctwatch: sleep error %d\n", error);
270 #endif
271 }
272 acct_dkwatcher = NULL;
273 ACCT_UNLOCK();
274
275 kthread_exit(0);
276 }
277
278 void
279 acct_init(void)
280 {
281
282 acct_state = ACCT_STOP;
283 acct_vp = NULLVP;
284 acct_cred = NULL;
285 lockinit(&acct_lock, PWAIT, "acctlk", 0, 0);
286 }
287
288 /*
289 * Accounting system call. Written based on the specification and
290 * previous implementation done by Mark Tinguely.
291 */
292 int
293 sys_acct(struct lwp *l, void *v, register_t *retval)
294 {
295 struct sys_acct_args /* {
296 syscallarg(const char *) path;
297 } */ *uap = v;
298 struct nameidata nd;
299 int error;
300
301 /* Make sure that the caller is root. */
302 if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_ACCOUNTING,
303 0, NULL, NULL, NULL)))
304 return (error);
305
306 /*
307 * If accounting is to be started to a file, open that file for
308 * writing and make sure it's a 'normal'.
309 */
310 if (SCARG(uap, path) != NULL) {
311 struct vattr va;
312 size_t pad;
313 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
314 l);
315 if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0)
316 return (error);
317 if (nd.ni_vp->v_type != VREG) {
318 VOP_UNLOCK(nd.ni_vp, 0);
319 error = EACCES;
320 goto bad;
321 }
322 if ((error = VOP_GETATTR(nd.ni_vp, &va, l->l_cred, l)) != 0) {
323 VOP_UNLOCK(nd.ni_vp, 0);
324 goto bad;
325 }
326
327 if ((pad = (va.va_size % sizeof(struct acct))) != 0) {
328 u_quad_t size = va.va_size - pad;
329 #ifdef DIAGNOSTIC
330 printf("Size of accounting file not a multiple of "
331 "%lu - incomplete record truncated\n",
332 (unsigned long)sizeof(struct acct));
333 #endif
334 VATTR_NULL(&va);
335 va.va_size = size;
336 error = VOP_SETATTR(nd.ni_vp, &va, l->l_cred, l);
337 if (error != 0) {
338 VOP_UNLOCK(nd.ni_vp, 0);
339 goto bad;
340 }
341 }
342 VOP_UNLOCK(nd.ni_vp, 0);
343 }
344
345 ACCT_LOCK();
346
347 /*
348 * If accounting was previously enabled, kill the old space-watcher,
349 * free credential for accounting file i/o,
350 * ... (and, if no new file was specified, leave).
351 */
352 acct_stop();
353 if (SCARG(uap, path) == NULL)
354 goto out;
355
356 /*
357 * Save the new accounting file vnode and credential,
358 * and schedule the new free space watcher.
359 */
360 acct_state = ACCT_ACTIVE;
361 acct_vp = nd.ni_vp;
362 acct_cred = l->l_cred;
363 kauth_cred_hold(acct_cred);
364
365 error = acct_chkfree(); /* Initial guess. */
366 if (error != 0) {
367 acct_stop();
368 goto out;
369 }
370
371 if (acct_dkwatcher == NULL) {
372 error = kthread_create1(acctwatch, NULL, &acct_dkwatcher,
373 "acctwatch");
374 if (error != 0)
375 acct_stop();
376 }
377
378 out:
379 ACCT_UNLOCK();
380 return (error);
381 bad:
382 vn_close(nd.ni_vp, FWRITE, l->l_cred, l);
383 return error;
384 }
385
386 /*
387 * Write out process accounting information, on process exit.
388 * Data to be written out is specified in Leffler, et al.
389 * and are enumerated below. (They're also noted in the system
390 * "acct.h" header file.)
391 */
392 int
393 acct_process(struct lwp *l)
394 {
395 struct acct acct;
396 struct timeval ut, st, tmp;
397 struct rusage *r;
398 int t, error = 0;
399 struct plimit *oplim = NULL;
400 struct proc *p = l->l_proc;
401
402 ACCT_LOCK();
403
404 /* If accounting isn't enabled, don't bother */
405 if (acct_state != ACCT_ACTIVE)
406 goto out;
407
408 /*
409 * Raise the file limit so that accounting can't be stopped by
410 * the user.
411 *
412 * XXX We should think about the CPU limit, too.
413 */
414 if (p->p_limit->p_refcnt > 1) {
415 oplim = p->p_limit;
416 p->p_limit = limcopy(p->p_limit);
417 }
418 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
419
420 /*
421 * Get process accounting information.
422 */
423
424 /* (1) The name of the command that ran */
425 memcpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm));
426
427 /* (2) The amount of user and system time that was used */
428 calcru(p, &ut, &st, NULL);
429 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
430 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
431
432 /* (3) The elapsed time the commmand ran (and its starting time) */
433 acct.ac_btime = p->p_stats->p_start.tv_sec;
434 getmicrotime(&tmp);
435 timersub(&tmp, &p->p_stats->p_start, &tmp);
436 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
437
438 /* (4) The average amount of memory used */
439 r = &p->p_stats->p_ru;
440 timeradd(&ut, &st, &tmp);
441 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
442 if (t)
443 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
444 else
445 acct.ac_mem = 0;
446
447 /* (5) The number of disk I/O operations done */
448 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
449
450 /* (6) The UID and GID of the process */
451 acct.ac_uid = kauth_cred_getuid(l->l_cred);
452 acct.ac_gid = kauth_cred_getgid(l->l_cred);
453
454 /* (7) The terminal from which the process was started */
455 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
456 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev;
457 else
458 acct.ac_tty = NODEV;
459
460 /* (8) The boolean flags that tell how the process terminated, etc. */
461 acct.ac_flag = p->p_acflag;
462
463 /*
464 * Now, just write the accounting information to the file.
465 */
466 VOP_LEASE(acct_vp, l, l->l_cred, LEASE_WRITE);
467 error = vn_rdwr(UIO_WRITE, acct_vp, (caddr_t)&acct,
468 sizeof(acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT,
469 acct_cred, NULL, NULL);
470 if (error != 0)
471 log(LOG_ERR, "Accounting: write failed %d\n", error);
472
473 if (oplim) {
474 limfree(p->p_limit);
475 p->p_limit = oplim;
476 }
477
478 out:
479 ACCT_UNLOCK();
480 return (error);
481 }
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