Line data Source code
1 : /* $OpenBSD: kern_acct.c,v 1.36 2018/04/28 03:13:04 visa 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/fcntl.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 0 : sys_acct(struct proc *p, void *v, register_t *retval)
99 : {
100 : struct sys_acct_args /* {
101 : syscallarg(const char *) path;
102 0 : } */ *uap = v;
103 0 : struct nameidata nd;
104 : int error;
105 :
106 : /* Make sure that the caller is root. */
107 0 : if ((error = suser(p)) != 0)
108 0 : 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 0 : if (SCARG(uap, path) != NULL) {
115 0 : NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
116 : p);
117 0 : if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0)
118 0 : return (error);
119 0 : VOP_UNLOCK(nd.ni_vp);
120 0 : if (nd.ni_vp->v_type != VREG) {
121 0 : vn_close(nd.ni_vp, FWRITE, p->p_ucred, p);
122 0 : 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 0 : if (acctp != NULL || savacctp != NULL) {
131 0 : wakeup(&acct_proc);
132 0 : error = vn_close((acctp != NULL ? acctp : savacctp), FWRITE,
133 0 : p->p_ucred, p);
134 0 : acctp = savacctp = NULL;
135 0 : }
136 0 : if (SCARG(uap, path) == NULL)
137 0 : return (0);
138 :
139 : /*
140 : * Save the new accounting file vnode, and schedule the new
141 : * free space watcher.
142 : */
143 0 : acctp = nd.ni_vp;
144 0 : if ((error = acct_start()) != 0) {
145 0 : acctp = NULL;
146 0 : (void)vn_close(nd.ni_vp, FWRITE, p->p_ucred, p);
147 0 : return (error);
148 : }
149 0 : return (0);
150 0 : }
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 0 : acct_process(struct proc *p)
160 : {
161 0 : struct acct acct;
162 0 : struct process *pr = p->p_p;
163 : struct rusage *r;
164 0 : struct timespec ut, st, tmp;
165 : int t;
166 : struct vnode *vp;
167 : int error;
168 :
169 : /* If accounting isn't enabled, don't bother */
170 0 : vp = acctp;
171 0 : if (vp == NULL)
172 0 : return (0);
173 :
174 : /*
175 : * Get process accounting information.
176 : */
177 :
178 : /* (1) The name of the command that ran */
179 0 : memcpy(acct.ac_comm, pr->ps_comm, sizeof acct.ac_comm);
180 :
181 : /* (2) The amount of user and system time that was used */
182 0 : calctsru(&pr->ps_tu, &ut, &st, NULL);
183 0 : acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_nsec);
184 0 : acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_nsec);
185 :
186 : /* (3) The elapsed time the command ran (and its starting time) */
187 0 : acct.ac_btime = pr->ps_start.tv_sec;
188 0 : getnanotime(&tmp);
189 0 : timespecsub(&tmp, &pr->ps_start, &tmp);
190 0 : acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_nsec);
191 :
192 : /* (4) The average amount of memory used */
193 0 : r = &p->p_ru;
194 0 : timespecadd(&ut, &st, &tmp);
195 0 : t = tmp.tv_sec * hz + tmp.tv_nsec / (1000 * tick);
196 0 : if (t)
197 0 : acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
198 : else
199 0 : acct.ac_mem = 0;
200 :
201 : /* (5) The number of disk I/O operations done */
202 0 : acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
203 :
204 : /* (6) The UID and GID of the process */
205 0 : acct.ac_uid = pr->ps_ucred->cr_ruid;
206 0 : acct.ac_gid = pr->ps_ucred->cr_rgid;
207 :
208 : /* (7) The terminal from which the process was started */
209 0 : if ((pr->ps_flags & PS_CONTROLT) &&
210 0 : pr->ps_pgrp->pg_session->s_ttyp)
211 0 : acct.ac_tty = pr->ps_pgrp->pg_session->s_ttyp->t_dev;
212 : else
213 0 : acct.ac_tty = NODEV;
214 :
215 : /* (8) The boolean flags that tell how the process terminated, etc. */
216 0 : acct.ac_flag = pr->ps_acflag;
217 :
218 : /*
219 : * Now, just write the accounting information to the file.
220 : */
221 0 : error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
222 : (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT|IO_NOLIMIT,
223 0 : p->p_ucred, NULL, p);
224 :
225 0 : return error;
226 0 : }
227 :
228 : /*
229 : * Encode_comp_t converts from ticks in seconds and microseconds
230 : * to ticks in 1/AHZ seconds. The encoding is described in
231 : * Leffler, et al., on page 63.
232 : */
233 :
234 : #define MANTSIZE 13 /* 13 bit mantissa. */
235 : #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
236 : #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
237 :
238 : comp_t
239 0 : encode_comp_t(u_long s, u_long ns)
240 : {
241 : int exp, rnd;
242 :
243 : exp = 0;
244 : rnd = 0;
245 0 : s *= AHZ;
246 0 : s += ns / (1000000000 / AHZ); /* Maximize precision. */
247 :
248 0 : while (s > MAXFRACT) {
249 0 : rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
250 0 : s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
251 0 : exp++;
252 : }
253 :
254 : /* If we need to round up, do it (and handle overflow correctly). */
255 0 : if (rnd && (++s > MAXFRACT)) {
256 0 : s >>= EXPSIZE;
257 0 : exp++;
258 0 : }
259 :
260 : /* Clean it up and polish it off. */
261 0 : exp <<= MANTSIZE; /* Shift the exponent into place */
262 0 : exp += s; /* and add on the mantissa. */
263 0 : return (exp);
264 : }
265 :
266 : int
267 0 : acct_start(void)
268 : {
269 : /* Already running. */
270 0 : if (acct_proc != NULL)
271 0 : return (0);
272 :
273 0 : return (kthread_create(acct_thread, NULL, &acct_proc, "acct"));
274 0 : }
275 :
276 : /*
277 : * Periodically check the file system to see if accounting
278 : * should be turned on or off. Beware the case where the vnode
279 : * has been vgone()'d out from underneath us, e.g. when the file
280 : * system containing the accounting file has been forcibly unmounted.
281 : */
282 : void
283 0 : acct_thread(void *arg)
284 : {
285 0 : struct statfs sb;
286 0 : struct proc *p = curproc;
287 :
288 0 : for (;;) {
289 0 : if (savacctp != NULL) {
290 0 : if (savacctp->v_type == VBAD) {
291 0 : (void) vn_close(savacctp, FWRITE, NOCRED, p);
292 0 : savacctp = NULL;
293 0 : break;
294 : }
295 0 : (void)VFS_STATFS(savacctp->v_mount, &sb, NULL);
296 0 : if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
297 0 : acctp = savacctp;
298 0 : savacctp = NULL;
299 0 : log(LOG_NOTICE, "Accounting resumed\n");
300 0 : }
301 0 : } else if (acctp != NULL) {
302 0 : if (acctp->v_type == VBAD) {
303 0 : (void) vn_close(acctp, FWRITE, NOCRED, p);
304 0 : acctp = NULL;
305 0 : break;
306 : }
307 0 : (void)VFS_STATFS(acctp->v_mount, &sb, NULL);
308 0 : if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
309 0 : savacctp = acctp;
310 0 : acctp = NULL;
311 0 : log(LOG_NOTICE, "Accounting suspended\n");
312 0 : }
313 : } else {
314 : break;
315 : }
316 0 : tsleep(&acct_proc, PPAUSE, "acct", acctchkfreq *hz);
317 : }
318 0 : acct_proc = NULL;
319 0 : kthread_exit(0);
320 : }
321 :
322 : void
323 0 : acct_shutdown(void)
324 : {
325 :
326 0 : struct proc *p = curproc;
327 :
328 0 : if (acctp != NULL || savacctp != NULL) {
329 0 : vn_close((acctp != NULL ? acctp : savacctp), FWRITE,
330 : NOCRED, p);
331 0 : acctp = savacctp = NULL;
332 0 : }
333 0 : }
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