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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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. */
142 * If accounting is to be started to a file, open that file for
143 * appending and make sure it's a 'normal'.
145 if (uap->path != NULL) {
146 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, td);
147 flags = FWRITE | O_APPEND;
148 error = vn_open(&nd, &flags, 0, -1);
151 NDFREE(&nd, NDF_ONLY_PNBUF);
153 error = mac_check_system_acct(td->td_ucred, nd.ni_vp);
155 VOP_UNLOCK(nd.ni_vp, 0, td);
156 vn_close(nd.ni_vp, flags, td->td_ucred, td);
160 VOP_UNLOCK(nd.ni_vp, 0, td);
161 if (nd.ni_vp->v_type != VREG) {
162 vn_close(nd.ni_vp, flags, td->td_ucred, td);
168 error = mac_check_system_acct(td->td_ucred, NULL);
177 * If accounting was previously enabled, kill the old space-watcher,
178 * close the file, and (if no new file was specified, leave).
180 * 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");
215 * Write out process accounting information, on process exit.
216 * Data to be written out is specified in Leffler, et al.
217 * and are enumerated below. (They're also noted in the system
218 * "acct.h" header file.)
225 struct timeval ut, st, tmp;
226 struct plimit *newlim, *oldlim;
234 * Lockless check of accounting condition before doing the hard
243 * If accounting isn't enabled, don't bother. Have to check again
244 * once we own the lock in case we raced with disabling of accounting
249 mtx_unlock(&acct_mtx);
256 * Get process accounting information.
260 /* (1) The name of the command that ran */
261 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
263 /* (2) The amount of user and system time that was used */
265 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
266 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
268 /* (3) The elapsed time the command ran (and its starting time) */
270 timevaladd(&tmp, &p->p_stats->p_start);
271 acct.ac_btime = tmp.tv_sec;
273 timevalsub(&tmp, &p->p_stats->p_start);
274 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
276 /* (4) The average amount of memory used */
277 r = &p->p_stats->p_ru;
279 timevaladd(&tmp, &st);
280 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
282 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
286 /* (5) The number of disk I/O operations done */
287 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
289 /* (6) The UID and GID of the process */
290 acct.ac_uid = p->p_ucred->cr_ruid;
291 acct.ac_gid = p->p_ucred->cr_rgid;
293 /* (7) The terminal from which the process was started */
294 SESS_LOCK(p->p_session);
295 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
296 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
299 SESS_UNLOCK(p->p_session);
301 /* (8) The boolean flags that tell how the process terminated, etc. */
302 acct.ac_flag = p->p_acflag;
306 * Finish doing things that require acct_mtx, and release acct_mtx.
308 uc = crhold(acctcred);
310 mtx_unlock(&acct_mtx);
313 * Eliminate any file size rlimit.
315 newlim = lim_alloc();
318 lim_copy(newlim, oldlim);
319 newlim->pl_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
325 * Write the accounting information to the file.
327 VOP_LEASE(vp, td, uc, LEASE_WRITE);
328 ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
329 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, uc, NOCRED,
337 * Encode_comp_t converts from ticks in seconds and microseconds
338 * to ticks in 1/AHZ seconds. The encoding is described in
339 * Leffler, et al., on page 63.
342 #define MANTSIZE 13 /* 13 bit mantissa. */
343 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
344 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
355 s += us / (1000000 / AHZ); /* Maximize precision. */
357 while (s > MAXFRACT) {
358 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
359 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
363 /* If we need to round up, do it (and handle overflow correctly). */
364 if (rnd && (++s > MAXFRACT)) {
369 /* Clean it up and polish it off. */
370 exp <<= MANTSIZE; /* Shift the exponent into place */
371 exp += s; /* and add on the mantissa. */
376 * Periodically check the filesystem to see if accounting
377 * should be turned on or off. Beware the case where the vnode
378 * has been vgone()'d out from underneath us, e.g. when the file
379 * system containing the accounting file has been forcibly unmounted.
391 * XXX arr: need to fix the issue of holding acct_mtx over
392 * the below vnode operations.
394 if (savacctp != NULLVP) {
395 if (savacctp->v_type == VBAD) {
396 (void) vn_close(savacctp, savacctflags, savacctcred,
399 savacctcred = NOCRED;
400 mtx_unlock(&acct_mtx);
403 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0);
404 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
406 acctcred = savacctcred;
407 acctflags = savacctflags;
409 savacctcred = NOCRED;
410 log(LOG_NOTICE, "Accounting resumed\n");
413 if (acctp == NULLVP) {
414 mtx_unlock(&acct_mtx);
417 if (acctp->v_type == VBAD) {
418 (void) vn_close(acctp, acctflags, acctcred, NULL);
422 mtx_unlock(&acct_mtx);
425 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0);
426 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
428 savacctflags = acctflags;
429 savacctcred = acctcred;
432 log(LOG_NOTICE, "Accounting suspended\n");
435 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL);
436 mtx_unlock(&acct_mtx);