2 * Copyright (c) 1994 Christopher G. Demetriou
3 * Copyright (c) 1982, 1986, 1989, 1993
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5 * (c) UNIX System Laboratories, Inc.
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39 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
40 * $FreeBSD: src/sys/kern/kern_acct.c,v 1.23.2.1 2002/07/24 18:33:55 johan Exp $
41 * $DragonFly: src/sys/kern/kern_acct.c,v 1.14 2004/09/17 17:06:59 dillon Exp $
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/sysproto.h>
48 #include <sys/mount.h>
49 #include <sys/vnode.h>
50 #include <sys/fcntl.h>
51 #include <sys/syslog.h>
52 #include <sys/kernel.h>
53 #include <sys/sysent.h>
54 #include <sys/sysctl.h>
55 #include <sys/namei.h>
57 #include <sys/resourcevar.h>
60 #include <vm/vm_zone.h>
63 * The routines implemented in this file are described in:
64 * Leffler, et al.: The Design and Implementation of the 4.3BSD
65 * UNIX Operating System (Addison Welley, 1989)
68 * Arguably, to simplify accounting operations, this mechanism should
69 * be replaced by one in which an accounting log file (similar to /dev/klog)
70 * is read by a user process, etc. However, that has its own problems.
74 * Internal accounting functions.
75 * The former's operation is described in Leffler, et al., and the latter
76 * was provided by UCB with the 4.4BSD-Lite release
78 static comp_t encode_comp_t (u_long, u_long);
79 static void acctwatch (void *);
82 * Accounting callout handle used for periodic scheduling of
85 static struct callout acctwatch_handle;
88 * Accounting vnode pointer, and saved vnode pointer.
90 static struct vnode *acctp;
91 static struct vnode *savacctp;
94 * Values associated with enabling and disabling accounting
96 static int acctsuspend = 2; /* stop accounting when < 2% free space left */
97 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
98 &acctsuspend, 0, "Percentage of free disk space below which accounting will be suspended");
100 static int acctresume = 4; /* resume when free space risen to > 4% */
101 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
102 &acctresume, 0, "Minimum percentage of free disk space needed to resume accounting");
104 static int acctchkfreq = 15; /* frequency (in seconds) to check space */
105 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
106 &acctchkfreq, 0, "Frequency (in seconds) of free disk space checking");
109 acct_init(void *arg __unused)
111 callout_init(&acctwatch_handle);
113 SYSINIT(acct, SI_SUB_DRIVERS, SI_ORDER_ANY, acct_init, NULL);
116 * Accounting system call. Written based on the specification and
117 * previous implementation done by Mark Tinguely.
121 struct acct_args /* {
122 syscallarg(char *) path;
125 struct thread *td = curthread;
129 /* Make sure that the caller is root. */
135 * If accounting is to be started to a file, open that file for
136 * appending and make sure it's a 'normal'.
138 if (SCARG(uap, path) != NULL) {
139 NDINIT(&nd, NAMEI_LOOKUP, 0, UIO_USERSPACE,
140 SCARG(uap, path), td);
141 error = vn_open(&nd, FWRITE | O_APPEND, 0);
144 NDFREE(&nd, NDF_ONLY_PNBUF);
145 VOP_UNLOCK(nd.ni_vp, NULL, 0, td);
146 if (nd.ni_vp->v_type != VREG) {
147 vn_close(nd.ni_vp, FWRITE | O_APPEND, td);
153 * If accounting was previously enabled, kill the old space-watcher,
154 * close the file, and (if no new file was specified, leave).
156 if (acctp != NULLVP || savacctp != NULLVP) {
157 callout_stop(&acctwatch_handle);
158 error = vn_close((acctp != NULLVP ? acctp : savacctp),
159 FWRITE | O_APPEND, td);
160 acctp = savacctp = NULLVP;
162 if (SCARG(uap, path) == NULL)
166 * Save the new accounting file vnode, and schedule the new
167 * free space watcher.
175 * Write out process accounting information, on process exit.
176 * Data to be written out is specified in Leffler, et al.
177 * and are enumerated below. (They're also noted in the system
178 * "acct.h" header file.)
182 acct_process(struct proc *p)
186 struct timeval ut, st, tmp;
189 struct thread *td = p->p_thread;
191 /* If accounting isn't enabled, don't bother */
197 * Get process accounting information.
200 /* (1) The name of the command that ran */
201 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
203 /* (2) The amount of user and system time that was used */
204 calcru(p, &ut, &st, NULL);
205 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
206 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
208 /* (3) The elapsed time the commmand ran (and its starting time) */
209 acct.ac_btime = p->p_thread->td_start.tv_sec;
211 timevalsub(&tmp, &p->p_thread->td_start);
212 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
214 /* (4) The average amount of memory used */
215 r = &p->p_stats->p_ru;
217 timevaladd(&tmp, &st);
218 t = tmp.tv_sec * hz + tmp.tv_usec / tick;
220 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
224 /* (5) The number of disk I/O operations done */
225 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
227 /* (6) The UID and GID of the process */
228 acct.ac_uid = p->p_ucred->cr_ruid;
229 acct.ac_gid = p->p_ucred->cr_rgid;
231 /* (7) The terminal from which the process was started */
232 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
233 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
235 acct.ac_tty = NOUDEV;
237 /* (8) The boolean flags that tell how the process terminated, etc. */
238 acct.ac_flag = p->p_acflag;
241 * Eliminate any file size rlimit.
243 if (p->p_limit->p_refcnt > 1 &&
244 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) {
245 p->p_limit->p_refcnt--;
246 p->p_limit = limcopy(p->p_limit);
248 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
251 * Write the accounting information to the file.
253 VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE);
254 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
255 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred,
260 * Encode_comp_t converts from ticks in seconds and microseconds
261 * to ticks in 1/AHZ seconds. The encoding is described in
262 * Leffler, et al., on page 63.
265 #define MANTSIZE 13 /* 13 bit mantissa. */
266 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
267 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
278 s += us / (1000000 / AHZ); /* Maximize precision. */
280 while (s > MAXFRACT) {
281 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
282 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
286 /* If we need to round up, do it (and handle overflow correctly). */
287 if (rnd && (++s > MAXFRACT)) {
292 /* Clean it up and polish it off. */
293 exp <<= MANTSIZE; /* Shift the exponent into place */
294 exp += s; /* and add on the mantissa. */
299 * Periodically check the file system to see if accounting
300 * should be turned on or off. Beware the case where the vnode
301 * has been vgone()'d out from underneath us, e.g. when the file
302 * system containing the accounting file has been forcibly unmounted.
311 if (savacctp != NULLVP) {
312 if (savacctp->v_type == VBAD) {
313 (void) vn_close(savacctp, FWRITE | O_APPEND, NULL);
317 (void)VFS_STATFS(savacctp->v_mount, &sb, NULL);
318 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
321 log(LOG_NOTICE, "Accounting resumed\n");
326 if (acctp->v_type == VBAD) {
327 (void) vn_close(acctp, FWRITE | O_APPEND, NULL);
331 (void)VFS_STATFS(acctp->v_mount, &sb, NULL);
332 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
335 log(LOG_NOTICE, "Accounting suspended\n");
338 callout_reset(&acctwatch_handle, acctchkfreq * hz, acctwatch, NULL);