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
43 #include <sys/param.h>
44 #include <sys/systm.h>
46 #include <sys/mutex.h>
47 #include <sys/sysproto.h>
49 #include <sys/mount.h>
50 #include <sys/vnode.h>
51 #include <sys/fcntl.h>
52 #include <sys/syslog.h>
53 #include <sys/kernel.h>
54 #include <sys/sysent.h>
55 #include <sys/sysctl.h>
56 #include <sys/namei.h>
58 #include <sys/resourcevar.h>
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)
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.
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
77 static comp_t encode_comp_t(u_long, u_long);
78 static void acctwatch(void *);
81 * Accounting callout used for periodic scheduling of acctwatch.
83 static struct callout acctwatch_callout;
86 * Accounting vnode pointer, and saved vnode pointer.
88 static struct vnode *acctp;
89 static struct vnode *savacctp;
92 * Values associated with enabling and disabling accounting
94 static int acctsuspend = 2; /* stop accounting when < 2% free space left */
95 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
96 &acctsuspend, 0, "percentage of free disk space below which accounting stops");
98 static int acctresume = 4; /* resume when free space risen to > 4% */
99 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
100 &acctresume, 0, "percentage of free disk space above which accounting resumes");
102 static int acctchkfreq = 15; /* frequency (in seconds) to check space */
103 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
104 &acctchkfreq, 0, "frequency for checking the free space");
107 * Accounting system call. Written based on the specification and
108 * previous implementation done by Mark Tinguely.
115 struct acct_args /* {
116 syscallarg(char *) path;
124 panic("acct"); /* XXXKSE DIAGNOSTIC */
125 /* Make sure that the caller is root. */
126 error = suser_xxx(td->td_proc->p_ucred, NULL, 0);
131 * If accounting is to be started to a file, open that file for
132 * writing and make sure it's a 'normal'.
134 if (SCARG(uap, path) != NULL) {
135 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
138 error = vn_open(&nd, &flags, 0);
141 NDFREE(&nd, NDF_ONLY_PNBUF);
142 VOP_UNLOCK(nd.ni_vp, 0, td);
143 if (nd.ni_vp->v_type != VREG) {
144 vn_close(nd.ni_vp, FWRITE, td->td_ucred, td);
151 * If accounting was previously enabled, kill the old space-watcher,
152 * close the file, and (if no new file was specified, leave).
154 if (acctp != NULLVP || savacctp != NULLVP) {
155 callout_stop(&acctwatch_callout);
156 error = vn_close((acctp != NULLVP ? acctp : savacctp), FWRITE,
158 acctp = savacctp = NULLVP;
160 if (SCARG(uap, path) == NULL)
164 * Save the new accounting file vnode, and schedule the new
165 * free space watcher.
168 callout_init(&acctwatch_callout, 0);
176 * Write out process accounting information, on process exit.
177 * Data to be written out is specified in Leffler, et al.
178 * and are enumerated below. (They're also noted in the system
179 * "acct.h" header file.)
186 struct proc *p = td->td_proc;
189 struct timeval ut, st, tmp;
193 /* If accounting isn't enabled, don't bother */
199 * Get process accounting information.
202 /* (1) The name of the command that ran */
203 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
205 /* (2) The amount of user and system time that was used */
206 mtx_lock_spin(&sched_lock);
207 calcru(p, &ut, &st, NULL);
208 mtx_unlock_spin(&sched_lock);
209 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
210 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
212 /* (3) The elapsed time the commmand ran (and its starting time) */
213 acct.ac_btime = p->p_stats->p_start.tv_sec;
215 timevalsub(&tmp, &p->p_stats->p_start);
216 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
218 /* (4) The average amount of memory used */
219 r = &p->p_stats->p_ru;
221 timevaladd(&tmp, &st);
222 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
224 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
228 /* (5) The number of disk I/O operations done */
229 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
231 /* (6) The UID and GID of the process */
232 acct.ac_uid = p->p_ucred->cr_ruid;
233 acct.ac_gid = p->p_ucred->cr_rgid;
235 /* (7) The terminal from which the process was started */
237 SESS_LOCK(p->p_session);
238 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
239 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
241 acct.ac_tty = NOUDEV;
242 SESS_UNLOCK(p->p_session);
245 /* (8) The boolean flags that tell how the process terminated, etc. */
246 acct.ac_flag = p->p_acflag;
249 * Eliminate any file size rlimit.
251 if (p->p_limit->p_refcnt > 1 &&
252 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) {
253 p->p_limit->p_refcnt--;
254 p->p_limit = limcopy(p->p_limit);
256 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
259 * Write the accounting information to the file.
261 VOP_LEASE(vp, td, td->td_ucred, LEASE_WRITE);
262 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
263 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, td->td_ucred,
268 * Encode_comp_t converts from ticks in seconds and microseconds
269 * to ticks in 1/AHZ seconds. The encoding is described in
270 * Leffler, et al., on page 63.
273 #define MANTSIZE 13 /* 13 bit mantissa. */
274 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
275 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
286 s += us / (1000000 / AHZ); /* Maximize precision. */
288 while (s > MAXFRACT) {
289 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
290 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
294 /* If we need to round up, do it (and handle overflow correctly). */
295 if (rnd && (++s > MAXFRACT)) {
300 /* Clean it up and polish it off. */
301 exp <<= MANTSIZE; /* Shift the exponent into place */
302 exp += s; /* and add on the mantissa. */
307 * Periodically check the file system to see if accounting
308 * should be turned on or off. Beware the case where the vnode
309 * has been vgone()'d out from underneath us, e.g. when the file
310 * system containing the accounting file has been forcibly unmounted.
319 if (savacctp != NULLVP) {
320 if (savacctp->v_type == VBAD) {
321 (void) vn_close(savacctp, FWRITE, NOCRED, NULL);
325 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0);
326 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
329 log(LOG_NOTICE, "Accounting resumed\n");
334 if (acctp->v_type == VBAD) {
335 (void) vn_close(acctp, FWRITE, NOCRED, NULL);
339 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0);
340 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
343 log(LOG_NOTICE, "Accounting suspended\n");
346 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL);