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 * $FreeBSD$
41 */
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/sysproto.h>
46 #include <sys/proc.h>
47 #include <sys/mount.h>
48 #include <sys/vnode.h>
49 #include <sys/fcntl.h>
50 #include <sys/syslog.h>
51 #include <sys/kernel.h>
52 #include <sys/sysent.h>
53 #include <sys/sysctl.h>
54 #include <sys/namei.h>
55 #include <sys/acct.h>
56 #include <sys/resourcevar.h>
57 #include <sys/tty.h>
58
59 /*
60 * The routines implemented in this file are described in:
61 * Leffler, et al.: The Design and Implementation of the 4.3BSD
62 * UNIX Operating System (Addison Welley, 1989)
63 * on pages 62-63.
64 *
65 * Arguably, to simplify accounting operations, this mechanism should
66 * be replaced by one in which an accounting log file (similar to /dev/klog)
67 * is read by a user process, etc. However, that has its own problems.
68 */
69
70 /*
71 * Internal accounting functions.
72 * The former's operation is described in Leffler, et al., and the latter
73 * was provided by UCB with the 4.4BSD-Lite release
74 */
75 static comp_t encode_comp_t __P((u_long, u_long));
76 static void acctwatch __P((void *));
77
78 /*
79 * Accounting callout handle used for periodic scheduling of
80 * acctwatch.
81 */
82 static struct callout_handle acctwatch_handle
83 = CALLOUT_HANDLE_INITIALIZER(&acctwatch_handle);
84
85 /*
86 * Accounting vnode pointer, and saved vnode pointer.
87 */
88 static struct vnode *acctp;
89 static struct vnode *savacctp;
90
91 /*
92 * Values associated with enabling and disabling accounting
93 */
94 static int acctsuspend = 2; /* stop accounting when < 2% free space left */
95 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
96 &acctsuspend, 0, "");
97
98 static int acctresume = 4; /* resume when free space risen to > 4% */
99 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
100 &acctresume, 0, "");
101
102 static int acctchkfreq = 15; /* frequency (in seconds) to check space */
103 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
104 &acctchkfreq, 0, "");
105
106 /*
107 * Accounting system call. Written based on the specification and
108 * previous implementation done by Mark Tinguely.
109 */
110 int
111 acct(a1, uap)
112 struct proc *a1;
113 struct acct_args /* {
114 syscallarg(char *) path;
115 } */ *uap;
116 {
117 struct proc *p = curproc; /* XXX */
118 struct nameidata nd;
119 int error;
120
121 /* Make sure that the caller is root. */
122 error = suser(p->p_ucred, &p->p_acflag);
123 if (error)
124 return (error);
125
126 /*
127 * If accounting is to be started to a file, open that file for
128 * writing and make sure it's a 'normal'.
129 */
130 if (SCARG(uap, path) != NULL) {
131 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
132 p);
133 error = vn_open(&nd, FWRITE, 0);
134 if (error)
135 return (error);
136 VOP_UNLOCK(nd.ni_vp, 0, p);
137 if (nd.ni_vp->v_type != VREG) {
138 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p);
139 return (EACCES);
140 }
141 }
142
143 /*
144 * If accounting was previously enabled, kill the old space-watcher,
145 * close the file, and (if no new file was specified, leave).
146 */
147 if (acctp != NULLVP || savacctp != NULLVP) {
148 untimeout(acctwatch, NULL, acctwatch_handle);
149 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE,
150 p->p_ucred, p);
151 acctp = savacctp = NULLVP;
152 }
153 if (SCARG(uap, path) == NULL)
154 return (error);
155
156 /*
157 * Save the new accounting file vnode, and schedule the new
158 * free space watcher.
159 */
160 acctp = nd.ni_vp;
161 acctwatch(NULL);
162 return (error);
163 }
164
165 /*
166 * Write out process accounting information, on process exit.
167 * Data to be written out is specified in Leffler, et al.
168 * and are enumerated below. (They're also noted in the system
169 * "acct.h" header file.)
170 */
171
172 int
173 acct_process(p)
174 struct proc *p;
175 {
176 struct acct acct;
177 struct rusage *r;
178 struct timeval ut, st, tmp;
179 int t;
180 struct vnode *vp;
181
182 /* If accounting isn't enabled, don't bother */
183 vp = acctp;
184 if (vp == NULLVP)
185 return (0);
186
187 /*
188 * Get process accounting information.
189 */
190
191 /* (1) The name of the command that ran */
192 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
193
194 /* (2) The amount of user and system time that was used */
195 calcru(p, &ut, &st, NULL);
196 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
197 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
198
199 /* (3) The elapsed time the commmand ran (and its starting time) */
200 acct.ac_btime = p->p_stats->p_start.tv_sec;
201 microtime(&tmp);
202 timevalsub(&tmp, &p->p_stats->p_start);
203 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
204
205 /* (4) The average amount of memory used */
206 r = &p->p_stats->p_ru;
207 tmp = ut;
208 timevaladd(&tmp, &st);
209 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
210 if (t)
211 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
212 else
213 acct.ac_mem = 0;
214
215 /* (5) The number of disk I/O operations done */
216 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
217
218 /* (6) The UID and GID of the process */
219 acct.ac_uid = p->p_cred->p_ruid;
220 acct.ac_gid = p->p_cred->p_rgid;
221
222 /* (7) The terminal from which the process was started */
223 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
224 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev;
225 else
226 acct.ac_tty = NODEV;
227
228 /* (8) The boolean flags that tell how the process terminated, etc. */
229 acct.ac_flag = p->p_acflag;
230
231 /*
232 * Eliminate any file size rlimit.
233 */
234 if (p->p_limit->p_refcnt > 1 &&
235 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) {
236 p->p_limit->p_refcnt--;
237 p->p_limit = limcopy(p->p_limit);
238 }
239 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
240
241 /*
242 * Write the accounting information to the file.
243 */
244 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
245 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
246 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred,
247 (int *)0, p));
248 }
249
250 /*
251 * Encode_comp_t converts from ticks in seconds and microseconds
252 * to ticks in 1/AHZ seconds. The encoding is described in
253 * Leffler, et al., on page 63.
254 */
255
256 #define MANTSIZE 13 /* 13 bit mantissa. */
257 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
258 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
259
260 static comp_t
261 encode_comp_t(s, us)
262 u_long s, us;
263 {
264 int exp, rnd;
265
266 exp = 0;
267 rnd = 0;
268 s *= AHZ;
269 s += us / (1000000 / AHZ); /* Maximize precision. */
270
271 while (s > MAXFRACT) {
272 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
273 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
274 exp++;
275 }
276
277 /* If we need to round up, do it (and handle overflow correctly). */
278 if (rnd && (++s > MAXFRACT)) {
279 s >>= EXPSIZE;
280 exp++;
281 }
282
283 /* Clean it up and polish it off. */
284 exp <<= MANTSIZE; /* Shift the exponent into place */
285 exp += s; /* and add on the mantissa. */
286 return (exp);
287 }
288
289 /*
290 * Periodically check the file system to see if accounting
291 * should be turned on or off. Beware the case where the vnode
292 * has been vgone()'d out from underneath us, e.g. when the file
293 * system containing the accounting file has been forcibly unmounted.
294 */
295 /* ARGSUSED */
296 static void
297 acctwatch(a)
298 void *a;
299 {
300 struct statfs sb;
301
302 if (savacctp != NULLVP) {
303 if (savacctp->v_type == VBAD) {
304 (void) vn_close(savacctp, FWRITE, NOCRED, NULL);
305 savacctp = NULLVP;
306 return;
307 }
308 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0);
309 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
310 acctp = savacctp;
311 savacctp = NULLVP;
312 log(LOG_NOTICE, "Accounting resumed\n");
313 }
314 } else {
315 if (acctp == NULLVP)
316 return;
317 if (acctp->v_type == VBAD) {
318 (void) vn_close(acctp, FWRITE, NOCRED, NULL);
319 acctp = NULLVP;
320 return;
321 }
322 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0);
323 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
324 savacctp = acctp;
325 acctp = NULLVP;
326 log(LOG_NOTICE, "Accounting suspended\n");
327 }
328 }
329 acctwatch_handle = timeout(acctwatch, NULL, acctchkfreq * hz);
330 }
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