FreeBSD-5.3/sys/kern/kern_acct.c
/*-
* Copyright (c) 1994 Christopher G. Demetriou
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/kern_acct.c,v 1.71 2004/06/17 17:16:48 phk Exp $");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysproto.h>
#include <sys/proc.h>
#include <sys/mac.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/fcntl.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/namei.h>
#include <sys/acct.h>
#include <sys/resourcevar.h>
#include <sys/tty.h>
/*
* The routines implemented in this file are described in:
* Leffler, et al.: The Design and Implementation of the 4.3BSD
* UNIX Operating System (Addison Welley, 1989)
* on pages 62-63.
*
* Arguably, to simplify accounting operations, this mechanism should
* be replaced by one in which an accounting log file (similar to /dev/klog)
* is read by a user process, etc. However, that has its own problems.
*/
/*
* Internal accounting functions.
* The former's operation is described in Leffler, et al., and the latter
* was provided by UCB with the 4.4BSD-Lite release
*/
static comp_t encode_comp_t(u_long, u_long);
static void acctwatch(void *);
/*
* Accounting callout used for periodic scheduling of acctwatch.
*/
static struct callout acctwatch_callout;
/*
* Accounting vnode pointer, saved vnode pointer, and flags for each.
*/
static struct vnode *acctp;
static struct ucred *acctcred;
static int acctflags;
static struct vnode *savacctp;
static struct ucred *savacctcred;
static int savacctflags;
static struct mtx acct_mtx;
MTX_SYSINIT(acct, &acct_mtx, "accounting", MTX_DEF);
/*
* Values associated with enabling and disabling accounting
*/
static int acctsuspend = 2; /* stop accounting when < 2% free space left */
SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
&acctsuspend, 0, "percentage of free disk space below which accounting stops");
static int acctresume = 4; /* resume when free space risen to > 4% */
SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
&acctresume, 0, "percentage of free disk space above which accounting resumes");
static int acctchkfreq = 15; /* frequency (in seconds) to check space */
SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
&acctchkfreq, 0, "frequency for checking the free space");
/*
* Accounting system call. Written based on the specification and
* previous implementation done by Mark Tinguely.
*
* MPSAFE
*/
int
acct(td, uap)
struct thread *td;
struct acct_args /* {
char *path;
} */ *uap;
{
struct nameidata nd;
int error, flags;
/* Make sure that the caller is root. */
error = suser(td);
if (error)
return (error);
mtx_lock(&Giant);
/*
* If accounting is to be started to a file, open that file for
* appending and make sure it's a 'normal'.
*/
if (uap->path != NULL) {
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->path, td);
flags = FWRITE | O_APPEND;
error = vn_open(&nd, &flags, 0, -1);
if (error)
goto done2;
NDFREE(&nd, NDF_ONLY_PNBUF);
#ifdef MAC
error = mac_check_system_acct(td->td_ucred, nd.ni_vp);
if (error) {
vn_close(nd.ni_vp, flags, td->td_ucred, td);
goto done2;
}
#endif
VOP_UNLOCK(nd.ni_vp, 0, td);
if (nd.ni_vp->v_type != VREG) {
vn_close(nd.ni_vp, flags, td->td_ucred, td);
error = EACCES;
goto done2;
}
#ifdef MAC
} else {
error = mac_check_system_acct(td->td_ucred, NULL);
if (error)
goto done2;
#endif
}
mtx_lock(&acct_mtx);
/*
* If accounting was previously enabled, kill the old space-watcher,
* close the file, and (if no new file was specified, leave).
*
* XXX arr: should not hold lock over vnode operation.
*/
if (acctp != NULLVP || savacctp != NULLVP) {
callout_stop(&acctwatch_callout);
error = vn_close((acctp != NULLVP ? acctp : savacctp),
(acctp != NULLVP ? acctflags : savacctflags),
(acctcred != NOCRED ? acctcred : savacctcred), td);
acctp = savacctp = NULLVP;
crfree(acctcred != NOCRED ? acctcred : savacctcred);
acctcred = savacctcred = NOCRED;
log(LOG_NOTICE, "Accounting disabled\n");
}
if (uap->path == NULL) {
mtx_unlock(&acct_mtx);
goto done2;
}
/*
* Save the new accounting file vnode, and schedule the new
* free space watcher.
*/
acctp = nd.ni_vp;
acctcred = crhold(td->td_ucred);
acctflags = flags;
callout_init(&acctwatch_callout, 0);
mtx_unlock(&acct_mtx);
log(LOG_NOTICE, "Accounting enabled\n");
acctwatch(NULL);
done2:
mtx_unlock(&Giant);
return (error);
}
/*
* Write out process accounting information, on process exit.
* Data to be written out is specified in Leffler, et al.
* and are enumerated below. (They're also noted in the system
* "acct.h" header file.)
*/
int
acct_process(td)
struct thread *td;
{
struct acct acct;
struct timeval ut, st, tmp;
struct plimit *newlim, *oldlim;
struct proc *p;
struct rusage *r;
struct ucred *uc;
struct vnode *vp;
int t, ret;
mtx_lock(&acct_mtx);
/* If accounting isn't enabled, don't bother */
vp = acctp;
if (vp == NULLVP) {
mtx_unlock(&acct_mtx);
return (0);
}
p = td->td_proc;
/*
* Get process accounting information.
*/
PROC_LOCK(p);
/* (1) The name of the command that ran */
bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
/* (2) The amount of user and system time that was used */
mtx_lock_spin(&sched_lock);
calcru(p, &ut, &st, NULL);
mtx_unlock_spin(&sched_lock);
acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
/* (3) The elapsed time the command ran (and its starting time) */
tmp = boottime;
timevaladd(&tmp, &p->p_stats->p_start);
acct.ac_btime = tmp.tv_sec;
microuptime(&tmp);
timevalsub(&tmp, &p->p_stats->p_start);
acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
/* (4) The average amount of memory used */
r = &p->p_stats->p_ru;
tmp = ut;
timevaladd(&tmp, &st);
t = tmp.tv_sec * hz + tmp.tv_usec / tick;
if (t)
acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
else
acct.ac_mem = 0;
/* (5) The number of disk I/O operations done */
acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
/* (6) The UID and GID of the process */
acct.ac_uid = p->p_ucred->cr_ruid;
acct.ac_gid = p->p_ucred->cr_rgid;
/* (7) The terminal from which the process was started */
SESS_LOCK(p->p_session);
if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
else
acct.ac_tty = NODEV;
SESS_UNLOCK(p->p_session);
/* (8) The boolean flags that tell how the process terminated, etc. */
acct.ac_flag = p->p_acflag;
PROC_UNLOCK(p);
/*
* Finish doing things that require acct_mtx, and release acct_mtx.
*/
uc = crhold(acctcred);
vref(vp);
mtx_unlock(&acct_mtx);
/*
* Eliminate any file size rlimit.
*/
newlim = lim_alloc();
PROC_LOCK(p);
oldlim = p->p_limit;
lim_copy(newlim, oldlim);
newlim->pl_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
p->p_limit = newlim;
PROC_UNLOCK(p);
lim_free(oldlim);
/*
* Write the accounting information to the file.
*/
VOP_LEASE(vp, td, uc, LEASE_WRITE);
ret = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
(off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, uc, NOCRED,
(int *)0, td);
vrele(vp);
crfree(uc);
return (ret);
}
/*
* Encode_comp_t converts from ticks in seconds and microseconds
* to ticks in 1/AHZ seconds. The encoding is described in
* Leffler, et al., on page 63.
*/
#define MANTSIZE 13 /* 13 bit mantissa. */
#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
static comp_t
encode_comp_t(s, us)
u_long s, us;
{
int exp, rnd;
exp = 0;
rnd = 0;
s *= AHZ;
s += us / (1000000 / AHZ); /* Maximize precision. */
while (s > MAXFRACT) {
rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
exp++;
}
/* If we need to round up, do it (and handle overflow correctly). */
if (rnd && (++s > MAXFRACT)) {
s >>= EXPSIZE;
exp++;
}
/* Clean it up and polish it off. */
exp <<= MANTSIZE; /* Shift the exponent into place */
exp += s; /* and add on the mantissa. */
return (exp);
}
/*
* Periodically check the filesystem to see if accounting
* should be turned on or off. Beware the case where the vnode
* has been vgone()'d out from underneath us, e.g. when the file
* system containing the accounting file has been forcibly unmounted.
*/
/* ARGSUSED */
static void
acctwatch(a)
void *a;
{
struct statfs sb;
mtx_lock(&acct_mtx);
/*
* XXX arr: need to fix the issue of holding acct_mtx over
* the below vnode operations.
*/
if (savacctp != NULLVP) {
if (savacctp->v_type == VBAD) {
(void) vn_close(savacctp, savacctflags, savacctcred,
NULL);
savacctp = NULLVP;
savacctcred = NOCRED;
mtx_unlock(&acct_mtx);
return;
}
(void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0);
if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
acctp = savacctp;
acctcred = savacctcred;
acctflags = savacctflags;
savacctp = NULLVP;
savacctcred = NOCRED;
log(LOG_NOTICE, "Accounting resumed\n");
}
} else {
if (acctp == NULLVP) {
mtx_unlock(&acct_mtx);
return;
}
if (acctp->v_type == VBAD) {
(void) vn_close(acctp, acctflags, acctcred, NULL);
acctp = NULLVP;
crfree(acctcred);
acctcred = NOCRED;
mtx_unlock(&acct_mtx);
return;
}
(void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0);
if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
savacctp = acctp;
savacctflags = acctflags;
savacctcred = acctcred;
acctp = NULLVP;
acctcred = NOCRED;
log(LOG_NOTICE, "Accounting suspended\n");
}
}
callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL);
mtx_unlock(&acct_mtx);
}