1 /* $OpenBSD: kern_acct.c,v 1.21 2007/04/12 22:14:15 tedu Exp $ */
2 /* $NetBSD: kern_acct.c,v 1.42 1996/02/04 02:15:12 christos Exp $ */
3
4 /*-
5 * Copyright (c) 1994 Christopher G. Demetriou
6 * Copyright (c) 1982, 1986, 1989, 1993
7 * The Regents of the University of California. All rights reserved.
8 * (c) UNIX System Laboratories, Inc.
9 * All or some portions of this file are derived from material licensed
10 * to the University of California by American Telephone and Telegraph
11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
12 * the permission of UNIX System Laboratories, Inc.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
39 */
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/proc.h>
44 #include <sys/mount.h>
45 #include <sys/vnode.h>
46 #include <sys/file.h>
47 #include <sys/syslog.h>
48 #include <sys/kernel.h>
49 #include <sys/namei.h>
50 #include <sys/errno.h>
51 #include <sys/acct.h>
52 #include <sys/resourcevar.h>
53 #include <sys/ioctl.h>
54 #include <sys/tty.h>
55 #include <sys/kthread.h>
56
57 #include <sys/syscallargs.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 */
73 comp_t encode_comp_t(u_long, u_long);
74 int acct_start(void);
75 void acct_thread(void *);
76 void acct_shutdown(void);
77
78 /*
79 * Accounting vnode pointer, and saved vnode pointer.
80 */
81 struct vnode *acctp;
82 struct vnode *savacctp;
83
84 /*
85 * Values associated with enabling and disabling accounting
86 */
87 int acctsuspend = 2; /* stop accounting when < 2% free space left */
88 int acctresume = 4; /* resume when free space risen to > 4% */
89 int acctchkfreq = 15; /* frequency (in seconds) to check space */
90
91 struct proc *acct_proc;
92
93 /*
94 * Accounting system call. Written based on the specification and
95 * previous implementation done by Mark Tinguely.
96 */
97 int
98 sys_acct(struct proc *p, void *v, register_t *retval)
99 {
100 struct sys_acct_args /* {
101 syscallarg(const char *) path;
102 } */ *uap = v;
103 struct nameidata nd;
104 int error;
105
106 /* Make sure that the caller is root. */
107 if ((error = suser(p, 0)) != 0)
108 return (error);
109
110 /*
111 * If accounting is to be started to a file, open that file for
112 * writing and make sure it's 'normal'.
113 */
114 if (SCARG(uap, path) != NULL) {
115 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
116 p);
117 if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0)
118 return (error);
119 VOP_UNLOCK(nd.ni_vp, 0, p);
120 if (nd.ni_vp->v_type != VREG) {
121 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p);
122 return (EACCES);
123 }
124 }
125
126 /*
127 * If accounting was previously enabled, kill the old space-watcher,
128 * close the file, and (if no new file was specified, leave).
129 */
130 if (acctp != NULL || savacctp != NULL) {
131 wakeup(&acct_proc);
132 error = vn_close((acctp != NULL ? acctp : savacctp), FWRITE,
133 p->p_ucred, p);
134 acctp = savacctp = NULL;
135 }
136 if (SCARG(uap, path) == NULL)
137 return (0);
138
139 /*
140 * Save the new accounting file vnode, and schedule the new
141 * free space watcher.
142 */
143 acctp = nd.ni_vp;
144 if ((error = acct_start()) != 0) {
145 acctp = NULL;
146 (void)vn_close(nd.ni_vp, FWRITE, p->p_ucred, p);
147 return (error);
148 }
149 return (0);
150 }
151
152 /*
153 * Write out process accounting information, on process exit.
154 * Data to be written out is specified in Leffler, et al.
155 * and are enumerated below. (They're also noted in the system
156 * "acct.h" header file.)
157 */
158 int
159 acct_process(struct proc *p)
160 {
161 struct acct acct;
162 struct rusage *r;
163 struct timeval ut, st, tmp;
164 int t;
165 struct vnode *vp;
166 struct plimit *oplim = NULL;
167 int error;
168
169 /* If accounting isn't enabled, don't bother */
170 vp = acctp;
171 if (vp == NULL)
172 return (0);
173
174 /*
175 * Raise the file limit so that accounting can't be stopped by the
176 * user. (XXX - we should think about the cpu limit too).
177 */
178 if (p->p_p->ps_limit->p_refcnt > 1) {
179 oplim = p->p_p->ps_limit;
180 p->p_p->ps_limit = limcopy(p->p_p->ps_limit);
181 }
182 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
183
184 /*
185 * Get process accounting information.
186 */
187
188 /* (1) The name of the command that ran */
189 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
190
191 /* (2) The amount of user and system time that was used */
192 calcru(p, &ut, &st, NULL);
193 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
194 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
195
196 /* (3) The elapsed time the commmand ran (and its starting time) */
197 acct.ac_btime = p->p_stats->p_start.tv_sec;
198 getmicrotime(&tmp);
199 timersub(&tmp, &p->p_stats->p_start, &tmp);
200 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
201
202 /* (4) The average amount of memory used */
203 r = &p->p_stats->p_ru;
204 timeradd(&ut, &st, &tmp);
205 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
206 if (t)
207 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
208 else
209 acct.ac_mem = 0;
210
211 /* (5) The number of disk I/O operations done */
212 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
213
214 /* (6) The UID and GID of the process */
215 acct.ac_uid = p->p_cred->p_ruid;
216 acct.ac_gid = p->p_cred->p_rgid;
217
218 /* (7) The terminal from which the process was started */
219 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
220 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev;
221 else
222 acct.ac_tty = NODEV;
223
224 /* (8) The boolean flags that tell how the process terminated, etc. */
225 acct.ac_flag = p->p_acflag;
226
227 /*
228 * Now, just write the accounting information to the file.
229 */
230 error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
231 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, NULL, p);
232
233 if (oplim) {
234 limfree(p->p_p->ps_limit);
235 p->p_p->ps_limit = oplim;
236 }
237
238 return error;
239 }
240
241 /*
242 * Encode_comp_t converts from ticks in seconds and microseconds
243 * to ticks in 1/AHZ seconds. The encoding is described in
244 * Leffler, et al., on page 63.
245 */
246
247 #define MANTSIZE 13 /* 13 bit mantissa. */
248 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
249 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
250
251 comp_t
252 encode_comp_t(u_long s, u_long us)
253 {
254 int exp, rnd;
255
256 exp = 0;
257 rnd = 0;
258 s *= AHZ;
259 s += us / (1000000 / AHZ); /* Maximize precision. */
260
261 while (s > MAXFRACT) {
262 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
263 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
264 exp++;
265 }
266
267 /* If we need to round up, do it (and handle overflow correctly). */
268 if (rnd && (++s > MAXFRACT)) {
269 s >>= EXPSIZE;
270 exp++;
271 }
272
273 /* Clean it up and polish it off. */
274 exp <<= MANTSIZE; /* Shift the exponent into place */
275 exp += s; /* and add on the mantissa. */
276 return (exp);
277 }
278
279 int
280 acct_start(void)
281 {
282 /* Already running. */
283 if (acct_proc != NULL)
284 return (0);
285
286 return (kthread_create(acct_thread, NULL, &acct_proc, "acct"));
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 void
297 acct_thread(void *arg)
298 {
299 struct statfs sb;
300 struct proc *p = curproc;
301
302 for (;;) {
303 if (savacctp != NULL) {
304 if (savacctp->v_type == VBAD) {
305 (void) vn_close(savacctp, FWRITE, NOCRED, p);
306 savacctp = NULL;
307 break;
308 }
309 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0);
310 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
311 acctp = savacctp;
312 savacctp = NULL;
313 log(LOG_NOTICE, "Accounting resumed\n");
314 }
315 } else if (acctp != NULL) {
316 if (acctp->v_type == VBAD) {
317 (void) vn_close(acctp, FWRITE, NOCRED, p);
318 acctp = NULL;
319 break;
320 }
321 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0);
322 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
323 savacctp = acctp;
324 acctp = NULL;
325 log(LOG_NOTICE, "Accounting suspended\n");
326 }
327 } else {
328 break;
329 }
330 tsleep(&acct_proc, PPAUSE, "acct", acctchkfreq *hz);
331 }
332 acct_proc = NULL;
333 kthread_exit(0);
334 }
335
336 void
337 acct_shutdown(void)
338 {
339
340 struct proc *p = curproc;
341
342 if (acctp != NULL || savacctp != NULL) {
343 vn_close((acctp != NULL ? acctp : savacctp), FWRITE,
344 NOCRED, p);
345 acctp = savacctp = NULL;
346 }
347 }