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.
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21 * This product includes software developed by the University of
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39 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
47 #include <sys/param.h>
48 #include <sys/systm.h>
50 #include <sys/mutex.h>
51 #include <sys/sysproto.h>
54 #include <sys/mount.h>
55 #include <sys/vnode.h>
56 #include <sys/fcntl.h>
57 #include <sys/syslog.h>
58 #include <sys/kernel.h>
59 #include <sys/sysent.h>
60 #include <sys/sysctl.h>
61 #include <sys/namei.h>
63 #include <sys/resourcevar.h>
67 * The routines implemented in this file are described in:
68 * Leffler, et al.: The Design and Implementation of the 4.3BSD
69 * UNIX Operating System (Addison Welley, 1989)
72 * Arguably, to simplify accounting operations, this mechanism should
73 * be replaced by one in which an accounting log file (similar to /dev/klog)
74 * is read by a user process, etc. However, that has its own problems.
78 * Internal accounting functions.
79 * The former's operation is described in Leffler, et al., and the latter
80 * was provided by UCB with the 4.4BSD-Lite release
82 static comp_t encode_comp_t(u_long, u_long);
83 static void acctwatch(void *);
86 * Accounting callout used for periodic scheduling of acctwatch.
88 static struct callout acctwatch_callout;
91 * Accounting vnode pointer, saved vnode pointer, and flags for each.
93 static struct vnode *acctp;
94 static struct ucred *acctcred;
96 static struct vnode *savacctp;
97 static struct ucred *savacctcred;
98 static int savacctflags;
100 static struct mtx acct_mtx;
101 MTX_SYSINIT(acct, &acct_mtx, "accounting", MTX_DEF);
104 * Values associated with enabling and disabling accounting
106 static int acctsuspend = 2; /* stop accounting when < 2% free space left */
107 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
108 &acctsuspend, 0, "percentage of free disk space below which accounting stops");
110 static int acctresume = 4; /* resume when free space risen to > 4% */
111 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
112 &acctresume, 0, "percentage of free disk space above which accounting resumes");
114 static int acctchkfreq = 15; /* frequency (in seconds) to check space */
115 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
116 &acctchkfreq, 0, "frequency for checking the free space");
119 * Accounting system call. Written based on the specification and
120 * previous implementation done by Mark Tinguely.
127 struct acct_args /* {
134 /* Make sure that the caller is root. */
141 * If accounting is to be started to a file, open that file for
142 * appending and make sure it's a 'normal'.
144 if (uap->path != NULL) {
145 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, td);
146 flags = FWRITE | O_APPEND;
147 error = vn_open(&nd, &flags, 0, -1);
150 NDFREE(&nd, NDF_ONLY_PNBUF);
152 error = mac_check_system_acct(td->td_ucred, nd.ni_vp);
154 vn_close(nd.ni_vp, flags, td->td_ucred, td);
158 VOP_UNLOCK(nd.ni_vp, 0, td);
159 if (nd.ni_vp->v_type != VREG) {
160 vn_close(nd.ni_vp, flags, td->td_ucred, td);
166 error = mac_check_system_acct(td->td_ucred, NULL);
173 * If accounting was previously enabled, kill the old space-watcher,
174 * close the file, and (if no new file was specified, leave).
178 * XXX arr: Should not hold lock over vnode operation.
182 if (acctp != NULLVP || savacctp != NULLVP) {
183 callout_stop(&acctwatch_callout);
184 error = vn_close((acctp != NULLVP ? acctp : savacctp),
185 (acctp != NULLVP ? acctflags : savacctflags),
186 (acctcred != NOCRED ? acctcred : savacctcred), td);
187 acctp = savacctp = NULLVP;
188 crfree(acctcred != NOCRED ? acctcred : savacctcred);
189 acctcred = savacctcred = NOCRED;
190 log(LOG_NOTICE, "Accounting disabled\n");
192 if (uap->path == NULL) {
193 mtx_unlock(&acct_mtx);
198 * Save the new accounting file vnode, and schedule the new
199 * free space watcher.
202 acctcred = crhold(td->td_ucred);
204 callout_init(&acctwatch_callout, 0);
205 mtx_unlock(&acct_mtx);
206 log(LOG_NOTICE, "Accounting enabled\n");
214 * Write out process accounting information, on process exit.
215 * Data to be written out is specified in Leffler, et al.
216 * and are enumerated below. (They're also noted in the system
217 * "acct.h" header file.)
224 struct proc *p = td->td_proc;
227 struct timeval ut, st, tmp;
234 /* If accounting isn't enabled, don't bother */
237 mtx_unlock(&acct_mtx);
242 * Get process accounting information.
246 /* (1) The name of the command that ran */
247 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
249 /* (2) The amount of user and system time that was used */
250 mtx_lock_spin(&sched_lock);
251 calcru(p, &ut, &st, NULL);
252 mtx_unlock_spin(&sched_lock);
253 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
254 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
256 /* (3) The elapsed time the command ran (and its starting time) */
258 timevaladd(&tmp, &p->p_stats->p_start);
259 acct.ac_btime = tmp.tv_sec;
261 timevalsub(&tmp, &p->p_stats->p_start);
262 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
264 /* (4) The average amount of memory used */
265 r = &p->p_stats->p_ru;
267 timevaladd(&tmp, &st);
268 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
270 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
274 /* (5) The number of disk I/O operations done */
275 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
277 /* (6) The UID and GID of the process */
278 acct.ac_uid = p->p_ucred->cr_ruid;
279 acct.ac_gid = p->p_ucred->cr_rgid;
281 /* (7) The terminal from which the process was started */
282 SESS_LOCK(p->p_session);
283 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
284 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
286 acct.ac_tty = NOUDEV;
287 SESS_UNLOCK(p->p_session);
289 /* (8) The boolean flags that tell how the process terminated, etc. */
290 acct.ac_flag = p->p_acflag;
294 * Write the accounting information to the file.
296 uc = crhold(acctcred);
298 mtx_unlock(&acct_mtx);
301 * Eliminate any file size rlimit.
303 if (p->p_limit->p_refcnt > 1) {
304 p->p_limit->p_refcnt--;
305 p->p_limit = limcopy(p->p_limit);
307 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
309 VOP_LEASE(vp, td, uc, LEASE_WRITE);
310 ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
311 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, uc, NOCRED,
319 * Encode_comp_t converts from ticks in seconds and microseconds
320 * to ticks in 1/AHZ seconds. The encoding is described in
321 * Leffler, et al., on page 63.
324 #define MANTSIZE 13 /* 13 bit mantissa. */
325 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
326 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
337 s += us / (1000000 / AHZ); /* Maximize precision. */
339 while (s > MAXFRACT) {
340 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
341 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
345 /* If we need to round up, do it (and handle overflow correctly). */
346 if (rnd && (++s > MAXFRACT)) {
351 /* Clean it up and polish it off. */
352 exp <<= MANTSIZE; /* Shift the exponent into place */
353 exp += s; /* and add on the mantissa. */
358 * Periodically check the filesystem to see if accounting
359 * should be turned on or off. Beware the case where the vnode
360 * has been vgone()'d out from underneath us, e.g. when the file
361 * system containing the accounting file has been forcibly unmounted.
373 * XXX arr: Need to fix the issue of holding acct_mtx over
374 * the below vnode operations.
377 if (savacctp != NULLVP) {
378 if (savacctp->v_type == VBAD) {
379 (void) vn_close(savacctp, savacctflags, savacctcred,
382 savacctcred = NOCRED;
383 mtx_unlock(&acct_mtx);
386 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0);
387 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
389 acctcred = savacctcred;
390 acctflags = savacctflags;
392 savacctcred = NOCRED;
393 log(LOG_NOTICE, "Accounting resumed\n");
396 if (acctp == NULLVP) {
397 mtx_unlock(&acct_mtx);
400 if (acctp->v_type == VBAD) {
401 (void) vn_close(acctp, acctflags, acctcred, NULL);
405 mtx_unlock(&acct_mtx);
408 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0);
409 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
411 savacctflags = acctflags;
412 savacctcred = acctcred;
415 log(LOG_NOTICE, "Accounting suspended\n");
418 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL);
419 mtx_unlock(&acct_mtx);