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 #include <vm/vm_zone.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 */
77 static comp_t encode_comp_t __P((u_long, u_long));
78 static void acctwatch __P((void *));
79
80 /*
81 * Accounting callout handle used for periodic scheduling of
82 * acctwatch.
83 */
84 static struct callout_handle acctwatch_handle
85 = CALLOUT_HANDLE_INITIALIZER(&acctwatch_handle);
86
87 /*
88 * Accounting vnode pointer, and saved vnode pointer.
89 */
90 static struct vnode *acctp;
91 static struct vnode *savacctp;
92
93 /*
94 * Values associated with enabling and disabling accounting
95 */
96 static int acctsuspend = 2; /* stop accounting when < 2% free space left */
97 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
98 &acctsuspend, 0, "");
99
100 static int acctresume = 4; /* resume when free space risen to > 4% */
101 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
102 &acctresume, 0, "");
103
104 static int acctchkfreq = 15; /* frequency (in seconds) to check space */
105 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
106 &acctchkfreq, 0, "");
107
108 /*
109 * Accounting system call. Written based on the specification and
110 * previous implementation done by Mark Tinguely.
111 */
112 int
113 acct(a1, uap)
114 struct proc *a1;
115 struct acct_args /* {
116 syscallarg(char *) path;
117 } */ *uap;
118 {
119 struct proc *p = curproc; /* XXX */
120 struct nameidata nd;
121 int error;
122
123 /* Make sure that the caller is root. */
124 error = suser(p);
125 if (error)
126 return (error);
127
128 /*
129 * If accounting is to be started to a file, open that file for
130 * appending and make sure it's a 'normal'.
131 */
132 if (SCARG(uap, path) != NULL) {
133 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
134 p);
135 error = vn_open(&nd, FWRITE | O_APPEND, 0);
136 if (error)
137 return (error);
138 NDFREE(&nd, NDF_ONLY_PNBUF);
139 VOP_UNLOCK(nd.ni_vp, 0, p);
140 if (nd.ni_vp->v_type != VREG) {
141 vn_close(nd.ni_vp, FWRITE | O_APPEND, p->p_ucred, p);
142 return (EACCES);
143 }
144 }
145
146 /*
147 * If accounting was previously enabled, kill the old space-watcher,
148 * close the file, and (if no new file was specified, leave).
149 */
150 if (acctp != NULLVP || savacctp != NULLVP) {
151 untimeout(acctwatch, NULL, acctwatch_handle);
152 error = vn_close((acctp != NULLVP ? acctp : savacctp),
153 FWRITE | O_APPEND, p->p_ucred, p);
154 acctp = savacctp = NULLVP;
155 }
156 if (SCARG(uap, path) == NULL)
157 return (error);
158
159 /*
160 * Save the new accounting file vnode, and schedule the new
161 * free space watcher.
162 */
163 acctp = nd.ni_vp;
164 acctwatch(NULL);
165 return (error);
166 }
167
168 /*
169 * Write out process accounting information, on process exit.
170 * Data to be written out is specified in Leffler, et al.
171 * and are enumerated below. (They're also noted in the system
172 * "acct.h" header file.)
173 */
174
175 int
176 acct_process(p)
177 struct proc *p;
178 {
179 struct acct acct;
180 struct rusage *r;
181 struct timeval ut, st, tmp;
182 int t;
183 struct vnode *vp;
184
185 /* If accounting isn't enabled, don't bother */
186 vp = acctp;
187 if (vp == NULLVP)
188 return (0);
189
190 /*
191 * Get process accounting information.
192 */
193
194 /* (1) The name of the command that ran */
195 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
196
197 /* (2) The amount of user and system time that was used */
198 calcru(p, &ut, &st, NULL);
199 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
200 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
201
202 /* (3) The elapsed time the commmand ran (and its starting time) */
203 acct.ac_btime = p->p_stats->p_start.tv_sec;
204 microtime(&tmp);
205 timevalsub(&tmp, &p->p_stats->p_start);
206 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
207
208 /* (4) The average amount of memory used */
209 r = &p->p_stats->p_ru;
210 tmp = ut;
211 timevaladd(&tmp, &st);
212 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
213 if (t)
214 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
215 else
216 acct.ac_mem = 0;
217
218 /* (5) The number of disk I/O operations done */
219 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
220
221 /* (6) The UID and GID of the process */
222 acct.ac_uid = p->p_cred->p_ruid;
223 acct.ac_gid = p->p_cred->p_rgid;
224
225 /* (7) The terminal from which the process was started */
226 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
227 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
228 else
229 acct.ac_tty = NOUDEV;
230
231 /* (8) The boolean flags that tell how the process terminated, etc. */
232 acct.ac_flag = p->p_acflag;
233
234 /*
235 * Eliminate any file size rlimit.
236 */
237 if (p->p_limit->p_refcnt > 1 &&
238 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) {
239 p->p_limit->p_refcnt--;
240 p->p_limit = limcopy(p->p_limit);
241 }
242 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
243
244 /*
245 * Write the accounting information to the file.
246 */
247 VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
248 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
249 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred,
250 (int *)0, p));
251 }
252
253 /*
254 * Encode_comp_t converts from ticks in seconds and microseconds
255 * to ticks in 1/AHZ seconds. The encoding is described in
256 * Leffler, et al., on page 63.
257 */
258
259 #define MANTSIZE 13 /* 13 bit mantissa. */
260 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
261 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
262
263 static comp_t
264 encode_comp_t(s, us)
265 u_long s, us;
266 {
267 int exp, rnd;
268
269 exp = 0;
270 rnd = 0;
271 s *= AHZ;
272 s += us / (1000000 / AHZ); /* Maximize precision. */
273
274 while (s > MAXFRACT) {
275 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
276 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
277 exp++;
278 }
279
280 /* If we need to round up, do it (and handle overflow correctly). */
281 if (rnd && (++s > MAXFRACT)) {
282 s >>= EXPSIZE;
283 exp++;
284 }
285
286 /* Clean it up and polish it off. */
287 exp <<= MANTSIZE; /* Shift the exponent into place */
288 exp += s; /* and add on the mantissa. */
289 return (exp);
290 }
291
292 /*
293 * Periodically check the file system to see if accounting
294 * should be turned on or off. Beware the case where the vnode
295 * has been vgone()'d out from underneath us, e.g. when the file
296 * system containing the accounting file has been forcibly unmounted.
297 */
298 /* ARGSUSED */
299 static void
300 acctwatch(a)
301 void *a;
302 {
303 struct statfs sb;
304
305 if (savacctp != NULLVP) {
306 if (savacctp->v_type == VBAD) {
307 (void) vn_close(savacctp, FWRITE | O_APPEND, NOCRED,
308 NULL);
309 savacctp = NULLVP;
310 return;
311 }
312 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0);
313 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
314 acctp = savacctp;
315 savacctp = NULLVP;
316 log(LOG_NOTICE, "Accounting resumed\n");
317 }
318 } else {
319 if (acctp == NULLVP)
320 return;
321 if (acctp->v_type == VBAD) {
322 (void) vn_close(acctp, FWRITE | O_APPEND, NOCRED, NULL);
323 acctp = NULLVP;
324 return;
325 }
326 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0);
327 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
328 savacctp = acctp;
329 acctp = NULLVP;
330 log(LOG_NOTICE, "Accounting suspended\n");
331 }
332 }
333 acctwatch_handle = timeout(acctwatch, NULL, acctchkfreq * hz);
334 }
Cache object: 86d112e27e99be923b3ad200f261d7a5
|