[dragonfly.git] / 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
 * $FreeBSD: src/sys/kern/kern_acct.c,v 1.23.2.1 2002/07/24 18:33:55 johan Exp $
 * $DragonFly: src/sys/kern/kern_acct.c,v 1.28 2008/05/08 01:26:00 dillon Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/proc.h>
#include <sys/priv.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/nlookup.h>
#include <sys/acct.h>
#include <sys/resourcevar.h>
#include <sys/tty.h>

#include <vm/vm_zone.h>

#include <sys/mplock2.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 handle used for periodic scheduling of
 * acctwatch.
 */
static struct	callout acctwatch_handle;

/*
 * Accounting vnode pointer, and saved vnode pointer.
 */
static struct	vnode *acctp;
static struct	vnode *savacctp;

/*
 * 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 will be suspended");

static int acctresume = 4;	/* resume when free space risen to > 4% */
SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
	&acctresume, 0, "Minimum percentage of free disk space needed to resume accounting");

static int acctchkfreq = 15;	/* frequency (in seconds) to check space */
SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
	&acctchkfreq, 0, "Frequency (in seconds) of free disk space checking");

static void
acct_init(void *arg __unused)
{
	callout_init(&acctwatch_handle);
}
SYSINIT(acct, SI_SUB_DRIVERS, SI_ORDER_ANY, acct_init, NULL);

/*
 * Accounting system call.  Written based on the specification and
 * previous implementation done by Mark Tinguely.
 *
 * acct(char *path)
 *
 * MPALMOSTSAFE
 */
int
sys_acct(struct acct_args *uap)
{
	struct thread *td = curthread;
	struct nlookupdata nd;
	struct vnode *vp;
	int error;

	error = priv_check(td, PRIV_ACCT);
	if (error)
		return (error);

	get_mplock();

	/*
	 * 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) {
		error = nlookup_init(&nd, uap->path, UIO_USERSPACE,
					NLC_LOCKVP);
		if (error == 0)
			error = vn_open(&nd, NULL, FWRITE | O_APPEND, 0);
		if (error == 0 && nd.nl_open_vp->v_type != VREG) 
			error = EACCES;
		if (error) {
			nlookup_done(&nd);
			goto done;
		}
		vp = nd.nl_open_vp;
		nd.nl_open_vp = NULL;
		nlookup_done(&nd);

		vn_unlock(vp);
	} else {
		vp = NULL;
	}

	/*
	 * If accounting was previously enabled, kill the old space-watcher,
	 * close the file.
	 */
	if (acctp != NULLVP || savacctp != NULLVP) {
		callout_stop(&acctwatch_handle);
		error = vn_close((acctp != NULLVP ? acctp : savacctp),
				FWRITE | O_APPEND);
		acctp = savacctp = NULLVP;
	}

	/*
	 * If no new file opened then leave.  We never did an nlookup so
	 * don't try cleaning it up.
	 */
	if (uap->path == NULL)
		goto done;

	/*
	 * Save the new accounting file vnode, and schedule the new
	 * free space watcher.
	 */
	acctp = vp;
	acctwatch(NULL);
done:
	rel_mplock();
	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(struct proc *p)
{
	struct acct acct;
	struct rusage *r;
	struct rusage ru;
	struct timeval tmp;
	struct rlimit rlim;
	int t;
	struct vnode *vp;

	/* If accounting isn't enabled, don't bother */
	vp = acctp;
	if (vp == NULLVP)
		return (0);

	/*
	 * Get process accounting information.
	 */

	/* (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 */
	calcru_proc(p, &ru);
	acct.ac_utime = encode_comp_t(ru.ru_utime.tv_sec, ru.ru_utime.tv_usec);
	acct.ac_stime = encode_comp_t(ru.ru_stime.tv_sec, ru.ru_stime.tv_usec);

	/* (3) The elapsed time the commmand ran (and its starting time) */
	acct.ac_btime = p->p_start.tv_sec;
	microtime(&tmp);
	timevalsub(&tmp, &p->p_start);
	acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);

	/* (4) The average amount of memory used */
	r = &p->p_ru;
	tmp = ru.ru_utime;;
	timevaladd(&tmp, &ru.ru_stime);
	t = tmp.tv_sec * hz + tmp.tv_usec / ustick;
	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 */
	if ((p->p_flags & 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 = NOUDEV;

	/* (8) The boolean flags that tell how the process terminated, etc. */
	acct.ac_flag = p->p_acflag;

	/*
	 * Eliminate any file size rlimit.
	 */
	rlim.rlim_cur = RLIM_INFINITY;
	rlim.rlim_max = RLIM_INFINITY;
	plimit_modify(p, RLIMIT_FSIZE, &rlim);

	/*
	 * Write the accounting information to the file.
	 */
	return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
	    (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred,
	    NULL));
}

/*
 * 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(u_long s, u_long 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 file system 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(void *a)
{
	struct statfs sb;

	if (savacctp != NULLVP) {
		if (savacctp->v_type == VBAD) {
			(void) vn_close(savacctp, FWRITE | O_APPEND);
			savacctp = NULLVP;
			return;
		}
		(void)VFS_STATFS(savacctp->v_mount, &sb, proc0.p_ucred);
		if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
			acctp = savacctp;
			savacctp = NULLVP;
			log(LOG_NOTICE, "Accounting resumed\n");
		}
	} else {
		if (acctp == NULLVP)
			return;
		if (acctp->v_type == VBAD) {
			(void) vn_close(acctp, FWRITE | O_APPEND);
			acctp = NULLVP;
			return;
		}
		(void)VFS_STATFS(acctp->v_mount, &sb, proc0.p_ucred);
		if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
			savacctp = acctp;
			acctp = NULLVP;
			log(LOG_NOTICE, "Accounting suspended\n");
		}
	}
	callout_reset(&acctwatch_handle, acctchkfreq * hz, acctwatch, NULL);
}
Commit	Line	Data
984263bc MD	1	/*-
	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.
	6	* All or some portions of this file are derived from material licensed
	7	* to the University of California by American Telephone and Telegraph
	8	* Co. or Unix System Laboratories, Inc. and are reproduced herein with
	9	* the permission of UNIX System Laboratories, Inc.
	10	*
	11	* Redistribution and use in source and binary forms, with or without
	12	* modification, are permitted provided that the following conditions
	13	* are met:
	14	* 1. Redistributions of source code must retain the above copyright
	15	* notice, this list of conditions and the following disclaimer.
	16	* 2. Redistributions in binary form must reproduce the above copyright
	17	* notice, this list of conditions and the following disclaimer in the
	18	* documentation and/or other materials provided with the distribution.
	19	* 3. All advertising materials mentioning features or use of this software
	20	* must display the following acknowledgement:
	21	* This product includes software developed by the University of
	22	* California, Berkeley and its contributors.
	23	* 4. Neither the name of the University nor the names of its contributors
	24	* may be used to endorse or promote products derived from this software
	25	* without specific prior written permission.
	26	*
	27	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	28	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	29	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	30	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	31	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	32	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	33	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	34	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	35	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	36	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	37	* SUCH DAMAGE.
	38	*
	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 $
8f1f6170	41	* $DragonFly: src/sys/kern/kern_acct.c,v 1.28 2008/05/08 01:26:00 dillon Exp $
984263bc MD	42	*/
	43
	44	#include <sys/param.h>
	45	#include <sys/systm.h>
	46	#include <sys/sysproto.h>
	47	#include <sys/proc.h>
895c1f85	48	#include <sys/priv.h>
984263bc MD	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>
fad57d0e	56	#include <sys/nlookup.h>
984263bc MD	57	#include <sys/acct.h>
	58	#include <sys/resourcevar.h>
	59	#include <sys/tty.h>
	60
	61	#include <vm/vm_zone.h>
	62
684a93c4 MD	63	#include <sys/mplock2.h>
684a93c4 MD	64
984263bc MD	65	/*
	66	* The routines implemented in this file are described in:
	67	* Leffler, et al.: The Design and Implementation of the 4.3BSD
	68	* UNIX Operating System (Addison Welley, 1989)
	69	* on pages 62-63.
	70	*
	71	* Arguably, to simplify accounting operations, this mechanism should
	72	* be replaced by one in which an accounting log file (similar to /dev/klog)
	73	* is read by a user process, etc. However, that has its own problems.
	74	*/
	75
	76	/*
	77	* Internal accounting functions.
	78	* The former's operation is described in Leffler, et al., and the latter
	79	* was provided by UCB with the 4.4BSD-Lite release
	80	*/
402ed7e1 RG	81	static comp_t encode_comp_t (u_long, u_long);
402ed7e1 RG	82	static void acctwatch (void *);
984263bc MD	83
	84	/*
	85	* Accounting callout handle used for periodic scheduling of
	86	* acctwatch.
	87	*/
5972dfb9	88	static struct callout acctwatch_handle;
984263bc MD	89
	90	/*
	91	* Accounting vnode pointer, and saved vnode pointer.
	92	*/
	93	static struct vnode *acctp;
	94	static struct vnode *savacctp;
	95
	96	/*
	97	* Values associated with enabling and disabling accounting
	98	*/
	99	static int acctsuspend = 2; /* stop accounting when < 2% free space left */
	100	SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
06723abb	101	&acctsuspend, 0, "Percentage of free disk space below which accounting will be suspended");
984263bc MD	102
	103	static int acctresume = 4; /* resume when free space risen to > 4% */
	104	SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
06723abb	105	&acctresume, 0, "Minimum percentage of free disk space needed to resume accounting");
984263bc MD	106
	107	static int acctchkfreq = 15; /* frequency (in seconds) to check space */
	108	SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
06723abb	109	&acctchkfreq, 0, "Frequency (in seconds) of free disk space checking");
984263bc	110
9009d750 MD	111	static void
	112	acct_init(void *arg __unused)
	113	{
	114	callout_init(&acctwatch_handle);
	115	}
	116	SYSINIT(acct, SI_SUB_DRIVERS, SI_ORDER_ANY, acct_init, NULL);
	117
984263bc MD	118	/*
	119	* Accounting system call. Written based on the specification and
	120	* previous implementation done by Mark Tinguely.
77153250 CP	121	*
77153250 CP	122	* acct(char *path)
3919ced0 MD	123	*
3919ced0 MD	124	* MPALMOSTSAFE
984263bc MD	125	*/
984263bc MD	126	int
753fd850	127	sys_acct(struct acct_args *uap)
984263bc	128	{
dadab5e9	129	struct thread *td = curthread;
fad57d0e MD	130	struct nlookupdata nd;
fad57d0e MD	131	struct vnode *vp;
984263bc MD	132	int error;
984263bc MD	133
d550b5e6	134	error = priv_check(td, PRIV_ACCT);
984263bc MD	135	if (error)
	136	return (error);
	137
3919ced0 MD	138	get_mplock();
3919ced0 MD	139
984263bc MD	140	/*
	141	* If accounting is to be started to a file, open that file for
	142	* appending and make sure it's a 'normal'.
	143	*/
ab2eb4eb DR	144	if (uap->path != NULL) {
ab2eb4eb DR	145	error = nlookup_init(&nd, uap->path, UIO_USERSPACE,
fad57d0e MD	146	NLC_LOCKVP);
	147	if (error == 0)
	148	error = vn_open(&nd, NULL, FWRITE \| O_APPEND, 0);
	149	if (error == 0 && nd.nl_open_vp->v_type != VREG)
	150	error = EACCES;
	151	if (error) {
	152	nlookup_done(&nd);
3919ced0	153	goto done;
984263bc	154	}
fad57d0e MD	155	vp = nd.nl_open_vp;
	156	nd.nl_open_vp = NULL;
	157	nlookup_done(&nd);
	158
a11aaa81	159	vn_unlock(vp);
fad57d0e MD	160	} else {
fad57d0e MD	161	vp = NULL;
984263bc MD	162	}
	163
	164	/*
	165	* If accounting was previously enabled, kill the old space-watcher,
fad57d0e	166	* close the file.
984263bc MD	167	*/
984263bc MD	168	if (acctp != NULLVP \|\| savacctp != NULLVP) {
5972dfb9	169	callout_stop(&acctwatch_handle);
984263bc	170	error = vn_close((acctp != NULLVP ? acctp : savacctp),
87de5057	171	FWRITE \| O_APPEND);
984263bc MD	172	acctp = savacctp = NULLVP;
984263bc MD	173	}
fad57d0e MD	174
	175	/*
	176	* If no new file opened then leave. We never did an nlookup so
	177	* don't try cleaning it up.
	178	*/
ab2eb4eb	179	if (uap->path == NULL)
3919ced0	180	goto done;
984263bc MD	181
	182	/*
	183	* Save the new accounting file vnode, and schedule the new
	184	* free space watcher.
	185	*/
fad57d0e	186	acctp = vp;
984263bc	187	acctwatch(NULL);
3919ced0 MD	188	done:
3919ced0 MD	189	rel_mplock();
984263bc MD	190	return (error);
	191	}
	192
	193	/*
	194	* Write out process accounting information, on process exit.
	195	* Data to be written out is specified in Leffler, et al.
	196	* and are enumerated below. (They're also noted in the system
	197	* "acct.h" header file.)
	198	*/
	199
	200	int
dadab5e9	201	acct_process(struct proc *p)
984263bc MD	202	{
	203	struct acct acct;
	204	struct rusage *r;
fde7ac71 SS	205	struct rusage ru;
fde7ac71 SS	206	struct timeval tmp;
c0b8a06d	207	struct rlimit rlim;
984263bc MD	208	int t;
	209	struct vnode *vp;
	210
	211	/* If accounting isn't enabled, don't bother */
	212	vp = acctp;
	213	if (vp == NULLVP)
	214	return (0);
	215
	216	/*
	217	* Get process accounting information.
	218	*/
	219
	220	/* (1) The name of the command that ran */
	221	bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
	222
	223	/* (2) The amount of user and system time that was used */
fde7ac71 SS	224	calcru_proc(p, &ru);
	225	acct.ac_utime = encode_comp_t(ru.ru_utime.tv_sec, ru.ru_utime.tv_usec);
	226	acct.ac_stime = encode_comp_t(ru.ru_stime.tv_sec, ru.ru_stime.tv_usec);
984263bc MD	227
984263bc MD	228	/* (3) The elapsed time the commmand ran (and its starting time) */
d9fa5f67	229	acct.ac_btime = p->p_start.tv_sec;
984263bc	230	microtime(&tmp);
d9fa5f67	231	timevalsub(&tmp, &p->p_start);
984263bc MD	232	acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
	233
	234	/* (4) The average amount of memory used */
fde7ac71 SS	235	r = &p->p_ru;
	236	tmp = ru.ru_utime;;
	237	timevaladd(&tmp, &ru.ru_stime);
a591f597	238	t = tmp.tv_sec * hz + tmp.tv_usec / ustick;
984263bc MD	239	if (t)
	240	acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
	241	else
	242	acct.ac_mem = 0;
	243
	244	/* (5) The number of disk I/O operations done */
	245	acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
	246
	247	/* (6) The UID and GID of the process */
41c20dac MD	248	acct.ac_uid = p->p_ucred->cr_ruid;
41c20dac MD	249	acct.ac_gid = p->p_ucred->cr_rgid;
984263bc MD	250
984263bc MD	251	/* (7) The terminal from which the process was started */
4643740a	252	if ((p->p_flags & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
984263bc MD	253	acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
	254	else
	255	acct.ac_tty = NOUDEV;
	256
	257	/* (8) The boolean flags that tell how the process terminated, etc. */
	258	acct.ac_flag = p->p_acflag;
	259
	260	/*
	261	* Eliminate any file size rlimit.
	262	*/
c0b8a06d MD	263	rlim.rlim_cur = RLIM_INFINITY;
c0b8a06d MD	264	rlim.rlim_max = RLIM_INFINITY;
8f1f6170	265	plimit_modify(p, RLIMIT_FSIZE, &rlim);
984263bc MD	266
	267	/*
	268	* Write the accounting information to the file.
	269	*/
984263bc MD	270	return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
984263bc MD	271	(off_t)0, UIO_SYSSPACE, IO_APPEND\|IO_UNIT, p->p_ucred,
60233e58	272	NULL));
984263bc MD	273	}
	274
	275	/*
	276	* Encode_comp_t converts from ticks in seconds and microseconds
	277	* to ticks in 1/AHZ seconds. The encoding is described in
	278	* Leffler, et al., on page 63.
	279	*/
	280
	281	#define MANTSIZE 13 /* 13 bit mantissa. */
	282	#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
	283	#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
	284
	285	static comp_t
77153250	286	encode_comp_t(u_long s, u_long us)
984263bc MD	287	{
	288	int exp, rnd;
	289
	290	exp = 0;
	291	rnd = 0;
	292	s *= AHZ;
	293	s += us / (1000000 / AHZ); /* Maximize precision. */
	294
	295	while (s > MAXFRACT) {
	296	rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
	297	s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
	298	exp++;
	299	}
	300
	301	/* If we need to round up, do it (and handle overflow correctly). */
	302	if (rnd && (++s > MAXFRACT)) {
	303	s >>= EXPSIZE;
	304	exp++;
	305	}
	306
	307	/* Clean it up and polish it off. */
	308	exp <<= MANTSIZE; /* Shift the exponent into place */
	309	exp += s; /* and add on the mantissa. */
	310	return (exp);
	311	}
	312
	313	/*
	314	* Periodically check the file system to see if accounting
	315	* should be turned on or off. Beware the case where the vnode
	316	* has been vgone()'d out from underneath us, e.g. when the file
	317	* system containing the accounting file has been forcibly unmounted.
	318	*/
	319	/* ARGSUSED */
	320	static void
77153250	321	acctwatch(void *a)
984263bc MD	322	{
	323	struct statfs sb;
	324
	325	if (savacctp != NULLVP) {
	326	if (savacctp->v_type == VBAD) {
87de5057	327	(void) vn_close(savacctp, FWRITE \| O_APPEND);
984263bc MD	328	savacctp = NULLVP;
	329	return;
	330	}
acde96db	331	(void)VFS_STATFS(savacctp->v_mount, &sb, proc0.p_ucred);
984263bc MD	332	if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
	333	acctp = savacctp;
	334	savacctp = NULLVP;
	335	log(LOG_NOTICE, "Accounting resumed\n");
	336	}
	337	} else {
	338	if (acctp == NULLVP)
	339	return;
	340	if (acctp->v_type == VBAD) {
87de5057	341	(void) vn_close(acctp, FWRITE \| O_APPEND);
984263bc MD	342	acctp = NULLVP;
	343	return;
	344	}
acde96db	345	(void)VFS_STATFS(acctp->v_mount, &sb, proc0.p_ucred);
984263bc MD	346	if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
	347	savacctp = acctp;
	348	acctp = NULLVP;
	349	log(LOG_NOTICE, "Accounting suspended\n");
	350	}
	351	}
5972dfb9	352	callout_reset(&acctwatch_handle, acctchkfreq * hz, acctwatch, NULL);
984263bc	353	}