summaryrefslogtreecommitdiffstats
path: root/sys/kern/kern_acct.c
blob: 11db4e9460c0b9b5dcac00cea466f45ab14e3ecc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
/*-
 * Copyright (c) 1994 Christopher G. Demetriou
 * Copyright (c) 1982, 1986, 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)kern_acct.c	8.1 (Berkeley) 6/14/93
 *	$Id: kern_acct.c,v 1.18 1997/11/06 19:29:07 phk Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/fcntl.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/namei.h>
#include <sys/acct.h>
#include <sys/resourcevar.h>
#include <sys/tty.h>

/*
 * The routines implemented in this file are described in:
 *      Leffler, et al.: The Design and Implementation of the 4.3BSD
 *	    UNIX Operating System (Addison Welley, 1989)
 * on pages 62-63.
 *
 * Arguably, to simplify accounting operations, this mechanism should
 * be replaced by one in which an accounting log file (similar to /dev/klog)
 * is read by a user process, etc.  However, that has its own problems.
 */

/*
 * Internal accounting functions.
 * The former's operation is described in Leffler, et al., and the latter
 * was provided by UCB with the 4.4BSD-Lite release
 */
static comp_t	encode_comp_t __P((u_long, u_long));
static void	acctwatch __P((void *));

/*
 * Accounting callout handle used for periodic scheduling of
 * acctwatch.
 */
static struct	callout_handle acctwatch_handle
    = CALLOUT_HANDLE_INITIALIZER(&acctwatch_handle);

/*
 * Accounting vnode pointer, and saved vnode pointer.
 */
static struct	vnode *acctp;
static struct	vnode *savacctp;

/*
 * Values associated with enabling and disabling accounting
 */
static int acctsuspend = 2;	/* stop accounting when < 2% free space left */
SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
	&acctsuspend, 0, "");

static int acctresume = 4;	/* resume when free space risen to > 4% */
SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
	&acctresume, 0, "");

static int acctchkfreq = 15;	/* frequency (in seconds) to check space */
SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
	&acctchkfreq, 0, "");

/*
 * Accounting system call.  Written based on the specification and
 * previous implementation done by Mark Tinguely.
 */
int
acct(a1, uap)
	struct proc *a1;
	struct acct_args /* {
		syscallarg(char *) path;
	} */ *uap;
{
	struct proc *p = curproc;	/* XXX */
	struct nameidata nd;
	int error;

	/* Make sure that the caller is root. */
	error = suser(p->p_ucred, &p->p_acflag);
	if (error)
		return (error);

	/*
	 * If accounting is to be started to a file, open that file for
	 * writing and make sure it's a 'normal'.
	 */
	if (SCARG(uap, path) != NULL) {
		NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
		       p);
		error = vn_open(&nd, FWRITE, 0);
		if (error)
			return (error);
		VOP_UNLOCK(nd.ni_vp, 0, p);
		if (nd.ni_vp->v_type != VREG) {
			vn_close(nd.ni_vp, FWRITE, p->p_ucred, p);
			return (EACCES);
		}
	}

	/*
	 * If accounting was previously enabled, kill the old space-watcher,
	 * close the file, and (if no new file was specified, leave).
	 */
	if (acctp != NULLVP || savacctp != NULLVP) {
		untimeout(acctwatch, NULL, acctwatch_handle);
		error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE,
		    p->p_ucred, p);
		acctp = savacctp = NULLVP;
	}
	if (SCARG(uap, path) == NULL)
		return (error);

	/*
	 * Save the new accounting file vnode, and schedule the new
	 * free space watcher.
	 */
	acctp = nd.ni_vp;
	acctwatch(NULL);
	return (error);
}

/*
 * Write out process accounting information, on process exit.
 * Data to be written out is specified in Leffler, et al.
 * and are enumerated below.  (They're also noted in the system
 * "acct.h" header file.)
 */

int
acct_process(p)
	struct proc *p;
{
	struct acct acct;
	struct rusage *r;
	struct timeval ut, st, tmp;
	int t;
	struct vnode *vp;

	/* If accounting isn't enabled, don't bother */
	vp = acctp;
	if (vp == NULLVP)
		return (0);

	/*
	 * Get process accounting information.
	 */

	/* (1) The name of the command that ran */
	bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);

	/* (2) The amount of user and system time that was used */
	calcru(p, &ut, &st, NULL);
	acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
	acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);

	/* (3) The elapsed time the commmand ran (and its starting time) */
	acct.ac_btime = p->p_stats->p_start.tv_sec;
	microtime(&tmp);
	timevalsub(&tmp, &p->p_stats->p_start);
	acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);

	/* (4) The average amount of memory used */
	r = &p->p_stats->p_ru;
	tmp = ut;
	timevaladd(&tmp, &st);
	t = tmp.tv_sec * hz + tmp.tv_usec / tick;
	if (t)
		acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
	else
		acct.ac_mem = 0;

	/* (5) The number of disk I/O operations done */
	acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);

	/* (6) The UID and GID of the process */
	acct.ac_uid = p->p_cred->p_ruid;
	acct.ac_gid = p->p_cred->p_rgid;

	/* (7) The terminal from which the process was started */
	if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
		acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev;
	else
		acct.ac_tty = NODEV;

	/* (8) The boolean flags that tell how the process terminated, etc. */
	acct.ac_flag = p->p_acflag;

	/*
	 * Eliminate any file size rlimit.
	 */
	if (p->p_limit->p_refcnt > 1 &&
	    (p->p_limit->p_lflags & PL_SHAREMOD) == 0) {
		p->p_limit->p_refcnt--;
		p->p_limit = limcopy(p->p_limit);
	} 
	p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;

	/*
	 * Write the accounting information to the file.
	 */
	VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
	return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
	    (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred,
	    (int *)0, p));
}

/*
 * Encode_comp_t converts from ticks in seconds and microseconds
 * to ticks in 1/AHZ seconds.  The encoding is described in
 * Leffler, et al., on page 63.
 */

#define	MANTSIZE	13			/* 13 bit mantissa. */
#define	EXPSIZE		3			/* Base 8 (3 bit) exponent. */
#define	MAXFRACT	((1 << MANTSIZE) - 1)	/* Maximum fractional value. */

static comp_t
encode_comp_t(s, us)
	u_long s, us;
{
	int exp, rnd;

	exp = 0;
	rnd = 0;
	s *= AHZ;
	s += us / (1000000 / AHZ);	/* Maximize precision. */

	while (s > MAXFRACT) {
	rnd = s & (1 << (EXPSIZE - 1));	/* Round up? */
		s >>= EXPSIZE;		/* Base 8 exponent == 3 bit shift. */
		exp++;
	}

	/* If we need to round up, do it (and handle overflow correctly). */
	if (rnd && (++s > MAXFRACT)) {
		s >>= EXPSIZE;
		exp++;
	}

	/* Clean it up and polish it off. */
	exp <<= MANTSIZE;		/* Shift the exponent into place */
	exp += s;			/* and add on the mantissa. */
	return (exp);
}

/*
 * Periodically check the file system to see if accounting
 * should be turned on or off.  Beware the case where the vnode
 * has been vgone()'d out from underneath us, e.g. when the file
 * system containing the accounting file has been forcibly unmounted.
 */
/* ARGSUSED */
static void
acctwatch(a)
	void *a;
{
	struct statfs sb;

	if (savacctp != NULLVP) {
		if (savacctp->v_type == VBAD) {
			(void) vn_close(savacctp, FWRITE, NOCRED, NULL);
			savacctp = NULLVP;
			return;
		}
		(void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0);
		if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
			acctp = savacctp;
			savacctp = NULLVP;
			log(LOG_NOTICE, "Accounting resumed\n");
		}
	} else {
		if (acctp == NULLVP)
			return;
		if (acctp->v_type == VBAD) {
			(void) vn_close(acctp, FWRITE, NOCRED, NULL);
			acctp = NULLVP;
			return;
		}
		(void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0);
		if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
			savacctp = acctp;
			acctp = NULLVP;
			log(LOG_NOTICE, "Accounting suspended\n");
		}
	}
	acctwatch_handle = timeout(acctwatch, NULL, acctchkfreq * hz);
}
OpenPOWER on IntegriCloud