[apple/xnu.git] / bsd / kern / kern_acct.c

/*
 * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*-
 * 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
 */
/* HISTORY
 * 08-May-95  Mac Gillon (mgillon) at NeXT
 *	Purged old history
 *  	New version based on 4.4
 */
/*
 * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */


#include <sys/param.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/mount_internal.h>
#include <sys/vnode_internal.h>
#include <sys/file_internal.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
#include <sys/namei.h>
#include <sys/errno.h>
#include <sys/acct.h>
#include <sys/resourcevar.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/sysproto.h>
#if CONFIG_MACF
#include <security/mac_framework.h>
#endif

/*
 * 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
 */
comp_t	encode_comp_t(uint32_t, uint32_t);
void	acctwatch(void *);
void	acct_init(void);

/*
 * Accounting vnode pointer, and suspended accounting vnode pointer.  States
 * are as follows:
 *
 *	acctp		suspend_acctp	state
 *	-------------	------------	------------------------------
 *	NULL		NULL		Accounting disabled
 *	!NULL		NULL		Accounting enabled
 *	NULL		!NULL		Accounting enabled, but suspended
 *	!NULL		!NULL		<not allowed>
 */
struct	vnode *acctp;
struct	vnode *suspend_acctp;

/*
 * Values associated with enabling and disabling accounting
 */
int	acctsuspend = 2;	/* stop accounting when < 2% free space left */
int	acctresume = 4;		/* resume when free space risen to > 4% */
int	acctchkfreq = 15;	/* frequency (in seconds) to check space */


static lck_grp_t       *acct_subsys_lck_grp;
static lck_mtx_t       *acct_subsys_mutex;

#define ACCT_SUBSYS_LOCK() lck_mtx_lock(acct_subsys_mutex)
#define ACCT_SUBSYS_UNLOCK() lck_mtx_unlock(acct_subsys_mutex)

void
acct_init(void)
{
	acct_subsys_lck_grp = lck_grp_alloc_init("acct", NULL);
	acct_subsys_mutex = lck_mtx_alloc_init(acct_subsys_lck_grp, NULL);
}


/*
 * Accounting system call.  Written based on the specification and
 * previous implementation done by Mark Tinguely.
 */
int
acct(proc_t p, struct acct_args *uap, __unused int *retval)
{
	struct nameidata nd;
	int error;
	struct vfs_context *ctx; 

	ctx = vfs_context_current();

	/* Make sure that the caller is root. */
	if ((error = suser(vfs_context_ucred(ctx), &p->p_acflag)))
		return (error);

	/*
	 * If accounting is to be started to a file, open that file for
	 * writing and make sure it's a 'normal'.
	 */
	if (uap->path != USER_ADDR_NULL) {
		NDINIT(&nd, LOOKUP, OP_OPEN, NOFOLLOW, UIO_USERSPACE, uap->path, ctx);
		if ((error = vn_open(&nd, FWRITE, 0)))
			return (error);
#if CONFIG_MACF
		error = mac_system_check_acct(vfs_context_ucred(ctx), nd.ni_vp);
		if (error) {
			vnode_put(nd.ni_vp);
			vn_close(nd.ni_vp, FWRITE, ctx);
			return (error);
		}
#endif
		vnode_put(nd.ni_vp);

		if (nd.ni_vp->v_type != VREG) {
			vn_close(nd.ni_vp, FWRITE, ctx);
			return (EACCES);
		}
	}
#if CONFIG_MACF
	else {
		error = mac_system_check_acct(vfs_context_ucred(ctx), NULL);
		if (error)
			return (error);
	}
#endif

	/*
	 * If accounting was previously enabled, kill the old space-watcher,
	 * close the file, and (if no new file was specified, leave).
	 */
	ACCT_SUBSYS_LOCK();
	if (acctp != NULLVP || suspend_acctp != NULLVP) {
		untimeout(acctwatch, NULL);
		error = vn_close((acctp != NULLVP ? acctp : suspend_acctp),
				FWRITE, vfs_context_current());

		acctp = suspend_acctp = NULLVP;
	}
	if (uap->path == USER_ADDR_NULL) {
		ACCT_SUBSYS_UNLOCK();
		return (error);
	}

	/*
	 * Save the new accounting file vnode, and schedule the new
	 * free space watcher.
	 */
	acctp = nd.ni_vp;
	ACCT_SUBSYS_UNLOCK();

	acctwatch(NULL);
	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(proc_t p)
{
	struct acct an_acct;
	struct rusage rup, *r;
	struct timeval ut, st, tmp;
	int t;
	int error;
	struct vnode *vp;
	kauth_cred_t safecred;
	struct session * sessp;
	struct  tty *tp;

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

	/*
	 * Get process accounting information.
	 */

	/* (1) The name of the command that ran */
	bcopy(p->p_comm, an_acct.ac_comm, sizeof an_acct.ac_comm);

	/* (2) The amount of user and system time that was used */
	calcru(p, &ut, &st, NULL);
	an_acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
	an_acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);

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

	/* (4) The average amount of memory used */
	proc_lock(p);
	rup = p->p_stats->p_ru;
	proc_unlock(p);
	r = &rup;
	tmp = ut;
	timevaladd(&tmp, &st);
	t = tmp.tv_sec * hz + tmp.tv_usec / tick;
	if (t)
		an_acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
	else
		an_acct.ac_mem = 0;

	/* (5) The number of disk I/O operations done */
	an_acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);

	/* (6) The UID and GID of the process */
	safecred = kauth_cred_proc_ref(p);

	an_acct.ac_uid = kauth_cred_getruid(safecred);
	an_acct.ac_gid = kauth_cred_getrgid(safecred);

	/* (7) The terminal from which the process was started */
	
	sessp = proc_session(p);
	if ((p->p_flag & P_CONTROLT) && (sessp != SESSION_NULL) && ((tp = SESSION_TP(sessp)) != TTY_NULL)) {
		tty_lock(tp);
		an_acct.ac_tty = tp->t_dev;
		tty_unlock(tp);
	 }else
		an_acct.ac_tty = NODEV;

	if (sessp != SESSION_NULL)
		session_rele(sessp);

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

	/*
	 * Now, just write the accounting information to the file.
	 */
	if ((error = vnode_getwithref(vp)) == 0) {
	        error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&an_acct, sizeof (an_acct),
				(off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, safecred,
				(int *)0, p);
		vnode_put(vp);
	}

	kauth_cred_unref(&safecred);
	ACCT_SUBSYS_UNLOCK();

	return (error);
}

/*
 * 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. */

comp_t
encode_comp_t(uint32_t s, uint32_t 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 */
void
acctwatch(__unused void *a)
{
	vfs_context_t ctx = vfs_context_current();
	struct vfs_attr va;

	VFSATTR_INIT(&va);
	VFSATTR_WANTED(&va, f_blocks);
	VFSATTR_WANTED(&va, f_bavail);

	ACCT_SUBSYS_LOCK();
	if (suspend_acctp != NULLVP) {
		/*
		 * Resuming accounting when accounting is suspended, and the
		 * filesystem containing the suspended accounting file goes
		 * below a low watermark
		 */
		if (suspend_acctp->v_type == VBAD) {
			(void) vn_close(suspend_acctp, FWRITE, vfs_context_kernel());
			suspend_acctp = NULLVP;
			ACCT_SUBSYS_UNLOCK();
			return;
		}
		(void)vfs_getattr(suspend_acctp->v_mount, &va, ctx);
		if (va.f_bavail > acctresume * va.f_blocks / 100) {
			acctp = suspend_acctp;
			suspend_acctp = NULLVP;
			log(LOG_NOTICE, "Accounting resumed\n");
		}
	} else if (acctp != NULLVP) {
		/*
		 * Suspending accounting when accounting is currently active,
		 * and the filesystem containing the active accounting file
		 * goes over a high watermark
		 */
		if (acctp->v_type == VBAD) {
			(void) vn_close(acctp, FWRITE, vfs_context_kernel());
			acctp = NULLVP;
			ACCT_SUBSYS_UNLOCK();
			return;
		}
		(void)vfs_getattr(acctp->v_mount, &va, ctx);
		if (va.f_bavail <= acctsuspend * va.f_blocks / 100) {
			suspend_acctp = acctp;
			acctp = NULLVP;
			log(LOG_NOTICE, "Accounting suspended\n");
		}
	} else {
		ACCT_SUBSYS_UNLOCK();
		return;
	}
	ACCT_SUBSYS_UNLOCK();
    
	timeout(acctwatch, NULL, acctchkfreq * hz);
}
Commit	Line	Data
1c79356b	1	/*
6d2010ae	2	* Copyright (c) 2000-2010 Apple Inc. All rights reserved.
5d5c5d0d	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
8f6c56a5	14	*
2d21ac55 A	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
	29	/*-
	30	* Copyright (c) 1982, 1986, 1989, 1993
	31	* The Regents of the University of California. All rights reserved.
	32	* (c) UNIX System Laboratories, Inc.
	33	* All or some portions of this file are derived from material licensed
	34	* to the University of California by American Telephone and Telegraph
	35	* Co. or Unix System Laboratories, Inc. and are reproduced herein with
	36	* the permission of UNIX System Laboratories, Inc.
	37	*
	38	* Redistribution and use in source and binary forms, with or without
	39	* modification, are permitted provided that the following conditions
	40	* are met:
	41	* 1. Redistributions of source code must retain the above copyright
	42	* notice, this list of conditions and the following disclaimer.
	43	* 2. Redistributions in binary form must reproduce the above copyright
	44	* notice, this list of conditions and the following disclaimer in the
	45	* documentation and/or other materials provided with the distribution.
	46	* 3. All advertising materials mentioning features or use of this software
	47	* must display the following acknowledgement:
	48	* This product includes software developed by the University of
	49	* California, Berkeley and its contributors.
	50	* 4. Neither the name of the University nor the names of its contributors
	51	* may be used to endorse or promote products derived from this software
	52	* without specific prior written permission.
	53	*
	54	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	55	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	56	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	57	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	58	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	59	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	60	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	61	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	62	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	63	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	64	* SUCH DAMAGE.
	65	*
	66	* @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
	67	*/
	68	/* HISTORY
	69	* 08-May-95 Mac Gillon (mgillon) at NeXT
	70	* Purged old history
	71	* New version based on 4.4
	72	*/
2d21ac55 A	73	/*
	74	* NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
	75	* support for mandatory and extensible security protections. This notice
	76	* is included in support of clause 2.2 (b) of the Apple Public License,
	77	* Version 2.0.
	78	*/
1c79356b A	79
	80
	81	#include <sys/param.h>
91447636 A	82	#include <sys/proc_internal.h>
	83	#include <sys/kauth.h>
	84	#include <sys/mount_internal.h>
	85	#include <sys/vnode_internal.h>
	86	#include <sys/file_internal.h>
1c79356b A	87	#include <sys/syslog.h>
	88	#include <sys/kernel.h>
	89	#include <sys/namei.h>
	90	#include <sys/errno.h>
	91	#include <sys/acct.h>
	92	#include <sys/resourcevar.h>
	93	#include <sys/ioctl.h>
	94	#include <sys/tty.h>
91447636	95	#include <sys/sysproto.h>
2d21ac55 A	96	#if CONFIG_MACF
	97	#include <security/mac_framework.h>
	98	#endif
1c79356b A	99
	100	/*
	101	* The routines implemented in this file are described in:
	102	* Leffler, et al.: The Design and Implementation of the 4.3BSD
	103	* UNIX Operating System (Addison Welley, 1989)
	104	* on pages 62-63.
	105	*
	106	* Arguably, to simplify accounting operations, this mechanism should
	107	* be replaced by one in which an accounting log file (similar to /dev/klog)
	108	* is read by a user process, etc. However, that has its own problems.
	109	*/
	110
	111	/*
	112	* Internal accounting functions.
	113	* The former's operation is described in Leffler, et al., and the latter
	114	* was provided by UCB with the 4.4BSD-Lite release
	115	*/
b0d623f7	116	comp_t encode_comp_t(uint32_t, uint32_t);
91447636	117	void acctwatch(void *);
fe8ab488	118	void acct_init(void);
1c79356b A	119
1c79356b A	120	/*
91447636 A	121	* Accounting vnode pointer, and suspended accounting vnode pointer. States
	122	* are as follows:
	123	*
	124	* acctp suspend_acctp state
	125	* ------------- ------------ ------------------------------
	126	* NULL NULL Accounting disabled
	127	* !NULL NULL Accounting enabled
	128	* NULL !NULL Accounting enabled, but suspended
	129	* !NULL !NULL <not allowed>
1c79356b A	130	*/
1c79356b A	131	struct vnode *acctp;
91447636	132	struct vnode *suspend_acctp;
1c79356b A	133
	134	/*
	135	* Values associated with enabling and disabling accounting
	136	*/
	137	int acctsuspend = 2; /* stop accounting when < 2% free space left */
	138	int acctresume = 4; /* resume when free space risen to > 4% */
	139	int acctchkfreq = 15; /* frequency (in seconds) to check space */
	140
fe8ab488 A	141
	142	static lck_grp_t *acct_subsys_lck_grp;
	143	static lck_mtx_t *acct_subsys_mutex;
	144
	145	#define ACCT_SUBSYS_LOCK() lck_mtx_lock(acct_subsys_mutex)
	146	#define ACCT_SUBSYS_UNLOCK() lck_mtx_unlock(acct_subsys_mutex)
	147
	148	void
	149	acct_init(void)
	150	{
	151	acct_subsys_lck_grp = lck_grp_alloc_init("acct", NULL);
	152	acct_subsys_mutex = lck_mtx_alloc_init(acct_subsys_lck_grp, NULL);
	153	}
	154
	155
1c79356b A	156	/*
	157	* Accounting system call. Written based on the specification and
	158	* previous implementation done by Mark Tinguely.
	159	*/
91447636	160	int
2d21ac55	161	acct(proc_t p, struct acct_args uap, __unused int retval)
1c79356b A	162	{
	163	struct nameidata nd;
	164	int error;
2d21ac55	165	struct vfs_context *ctx;
91447636	166
2d21ac55	167	ctx = vfs_context_current();
1c79356b A	168
1c79356b A	169	/* Make sure that the caller is root. */
2d21ac55	170	if ((error = suser(vfs_context_ucred(ctx), &p->p_acflag)))
1c79356b A	171	return (error);
	172
	173	/*
	174	* If accounting is to be started to a file, open that file for
	175	* writing and make sure it's a 'normal'.
	176	*/
91447636	177	if (uap->path != USER_ADDR_NULL) {
6d2010ae	178	NDINIT(&nd, LOOKUP, OP_OPEN, NOFOLLOW, UIO_USERSPACE, uap->path, ctx);
91447636	179	if ((error = vn_open(&nd, FWRITE, 0)))
1c79356b	180	return (error);
2d21ac55 A	181	#if CONFIG_MACF
	182	error = mac_system_check_acct(vfs_context_ucred(ctx), nd.ni_vp);
	183	if (error) {
	184	vnode_put(nd.ni_vp);
	185	vn_close(nd.ni_vp, FWRITE, ctx);
	186	return (error);
	187	}
	188	#endif
91447636 A	189	vnode_put(nd.ni_vp);
91447636 A	190
1c79356b	191	if (nd.ni_vp->v_type != VREG) {
2d21ac55	192	vn_close(nd.ni_vp, FWRITE, ctx);
1c79356b A	193	return (EACCES);
	194	}
	195	}
2d21ac55 A	196	#if CONFIG_MACF
	197	else {
	198	error = mac_system_check_acct(vfs_context_ucred(ctx), NULL);
	199	if (error)
	200	return (error);
	201	}
	202	#endif
1c79356b A	203
	204	/*
	205	* If accounting was previously enabled, kill the old space-watcher,
	206	* close the file, and (if no new file was specified, leave).
	207	*/
fe8ab488	208	ACCT_SUBSYS_LOCK();
91447636	209	if (acctp != NULLVP \|\| suspend_acctp != NULLVP) {
fe8ab488	210	untimeout(acctwatch, NULL);
2d21ac55 A	211	error = vn_close((acctp != NULLVP ? acctp : suspend_acctp),
2d21ac55 A	212	FWRITE, vfs_context_current());
91447636 A	213
91447636 A	214	acctp = suspend_acctp = NULLVP;
1c79356b	215	}
fe8ab488 A	216	if (uap->path == USER_ADDR_NULL) {
fe8ab488 A	217	ACCT_SUBSYS_UNLOCK();
1c79356b	218	return (error);
fe8ab488	219	}
1c79356b A	220
	221	/*
	222	* Save the new accounting file vnode, and schedule the new
	223	* free space watcher.
	224	*/
	225	acctp = nd.ni_vp;
fe8ab488 A	226	ACCT_SUBSYS_UNLOCK();
fe8ab488 A	227
1c79356b A	228	acctwatch(NULL);
	229	return (error);
	230	}
	231
	232	/*
	233	* Write out process accounting information, on process exit.
	234	* Data to be written out is specified in Leffler, et al.
	235	* and are enumerated below. (They're also noted in the system
	236	* "acct.h" header file.)
	237	*/
91447636	238	int
2d21ac55	239	acct_process(proc_t p)
1c79356b	240	{
91447636	241	struct acct an_acct;
2d21ac55	242	struct rusage rup, *r;
1c79356b	243	struct timeval ut, st, tmp;
91447636 A	244	int t;
91447636 A	245	int error;
1c79356b	246	struct vnode *vp;
0c530ab8	247	kauth_cred_t safecred;
2d21ac55	248	struct session * sessp;
b0d623f7	249	struct tty *tp;
1c79356b A	250
1c79356b A	251	/* If accounting isn't enabled, don't bother */
fe8ab488	252	ACCT_SUBSYS_LOCK();
1c79356b	253	vp = acctp;
fe8ab488 A	254	if (vp == NULLVP) {
fe8ab488 A	255	ACCT_SUBSYS_UNLOCK();
1c79356b	256	return (0);
fe8ab488	257	}
1c79356b A	258
	259	/*
	260	* Get process accounting information.
	261	*/
	262
	263	/* (1) The name of the command that ran */
91447636	264	bcopy(p->p_comm, an_acct.ac_comm, sizeof an_acct.ac_comm);
1c79356b A	265
	266	/* (2) The amount of user and system time that was used */
	267	calcru(p, &ut, &st, NULL);
91447636 A	268	an_acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
91447636 A	269	an_acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
1c79356b A	270
1c79356b A	271	/* (3) The elapsed time the commmand ran (and its starting time) */
2d21ac55	272	an_acct.ac_btime = p->p_start.tv_sec;
91447636	273	microtime(&tmp);
2d21ac55	274	timevalsub(&tmp, &p->p_start);
91447636	275	an_acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
1c79356b A	276
1c79356b A	277	/* (4) The average amount of memory used */
2d21ac55 A	278	proc_lock(p);
	279	rup = p->p_stats->p_ru;
	280	proc_unlock(p);
	281	r = &rup;
1c79356b A	282	tmp = ut;
	283	timevaladd(&tmp, &st);
	284	t = tmp.tv_sec * hz + tmp.tv_usec / tick;
	285	if (t)
91447636	286	an_acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
1c79356b	287	else
91447636	288	an_acct.ac_mem = 0;
1c79356b A	289
1c79356b A	290	/* (5) The number of disk I/O operations done */
91447636	291	an_acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
1c79356b A	292
1c79356b A	293	/* (6) The UID and GID of the process */
2d21ac55 A	294	safecred = kauth_cred_proc_ref(p);
2d21ac55 A	295
6d2010ae A	296	an_acct.ac_uid = kauth_cred_getruid(safecred);
6d2010ae A	297	an_acct.ac_gid = kauth_cred_getrgid(safecred);
1c79356b A	298
1c79356b A	299	/* (7) The terminal from which the process was started */
2d21ac55 A	300
2d21ac55 A	301	sessp = proc_session(p);
b0d623f7 A	302	if ((p->p_flag & P_CONTROLT) && (sessp != SESSION_NULL) && ((tp = SESSION_TP(sessp)) != TTY_NULL)) {
	303	tty_lock(tp);
	304	an_acct.ac_tty = tp->t_dev;
	305	tty_unlock(tp);
2d21ac55	306	}else
91447636	307	an_acct.ac_tty = NODEV;
1c79356b	308
2d21ac55 A	309	if (sessp != SESSION_NULL)
	310	session_rele(sessp);
	311
1c79356b	312	/* (8) The boolean flags that tell how the process terminated, etc. */
91447636	313	an_acct.ac_flag = p->p_acflag;
1c79356b A	314
	315	/*
	316	* Now, just write the accounting information to the file.
	317	*/
91447636 A	318	if ((error = vnode_getwithref(vp)) == 0) {
91447636 A	319	error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&an_acct, sizeof (an_acct),
b0d623f7	320	(off_t)0, UIO_SYSSPACE, IO_APPEND\|IO_UNIT, safecred,
91447636 A	321	(int *)0, p);
	322	vnode_put(vp);
	323	}
2d21ac55	324
0c530ab8	325	kauth_cred_unref(&safecred);
fe8ab488 A	326	ACCT_SUBSYS_UNLOCK();
fe8ab488 A	327
91447636	328	return (error);
1c79356b A	329	}
	330
	331	/*
	332	* Encode_comp_t converts from ticks in seconds and microseconds
	333	* to ticks in 1/AHZ seconds. The encoding is described in
	334	* Leffler, et al., on page 63.
	335	*/
	336
	337	#define MANTSIZE 13 /* 13 bit mantissa. */
	338	#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
	339	#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
	340
	341	comp_t
b0d623f7	342	encode_comp_t(uint32_t s, uint32_t us)
1c79356b A	343	{
	344	int exp, rnd;
	345
	346	exp = 0;
	347	rnd = 0;
	348	s *= AHZ;
	349	s += us / (1000000 / AHZ); /* Maximize precision. */
	350
	351	while (s > MAXFRACT) {
	352	rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
	353	s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
	354	exp++;
	355	}
	356
	357	/* If we need to round up, do it (and handle overflow correctly). */
	358	if (rnd && (++s > MAXFRACT)) {
	359	s >>= EXPSIZE;
	360	exp++;
	361	}
	362
	363	/* Clean it up and polish it off. */
	364	exp <<= MANTSIZE; /* Shift the exponent into place */
	365	exp += s; /* and add on the mantissa. */
	366	return (exp);
	367	}
	368
1c79356b A	369	/*
	370	* Periodically check the file system to see if accounting
	371	* should be turned on or off. Beware the case where the vnode
	372	* has been vgone()'d out from underneath us, e.g. when the file
	373	* system containing the accounting file has been forcibly unmounted.
	374	*/
	375	/* ARGSUSED */
	376	void
91447636	377	acctwatch(__unused void *a)
1c79356b	378	{
2d21ac55	379	vfs_context_t ctx = vfs_context_current();
91447636 A	380	struct vfs_attr va;
	381
	382	VFSATTR_INIT(&va);
	383	VFSATTR_WANTED(&va, f_blocks);
	384	VFSATTR_WANTED(&va, f_bavail);
91447636	385
fe8ab488	386	ACCT_SUBSYS_LOCK();
91447636 A	387	if (suspend_acctp != NULLVP) {
	388	/*
	389	* Resuming accounting when accounting is suspended, and the
	390	* filesystem containing the suspended accounting file goes
	391	* below a low watermark
	392	*/
	393	if (suspend_acctp->v_type == VBAD) {
2d21ac55	394	(void) vn_close(suspend_acctp, FWRITE, vfs_context_kernel());
91447636	395	suspend_acctp = NULLVP;
fe8ab488	396	ACCT_SUBSYS_UNLOCK();
1c79356b A	397	return;
1c79356b A	398	}
2d21ac55	399	(void)vfs_getattr(suspend_acctp->v_mount, &va, ctx);
91447636 A	400	if (va.f_bavail > acctresume * va.f_blocks / 100) {
	401	acctp = suspend_acctp;
	402	suspend_acctp = NULLVP;
1c79356b A	403	log(LOG_NOTICE, "Accounting resumed\n");
	404	}
	405	} else if (acctp != NULLVP) {
91447636 A	406	/*
	407	* Suspending accounting when accounting is currently active,
	408	* and the filesystem containing the active accounting file
	409	* goes over a high watermark
	410	*/
1c79356b	411	if (acctp->v_type == VBAD) {
2d21ac55	412	(void) vn_close(acctp, FWRITE, vfs_context_kernel());
1c79356b	413	acctp = NULLVP;
fe8ab488	414	ACCT_SUBSYS_UNLOCK();
1c79356b A	415	return;
1c79356b A	416	}
2d21ac55	417	(void)vfs_getattr(acctp->v_mount, &va, ctx);
91447636 A	418	if (va.f_bavail <= acctsuspend * va.f_blocks / 100) {
91447636 A	419	suspend_acctp = acctp;
1c79356b A	420	acctp = NULLVP;
	421	log(LOG_NOTICE, "Accounting suspended\n");
	422	}
	423	} else {
fe8ab488	424	ACCT_SUBSYS_UNLOCK();
1c79356b	425	return;
fe8ab488 A	426	}
	427	ACCT_SUBSYS_UNLOCK();
	428
	429	timeout(acctwatch, NULL, acctchkfreq * hz);
1c79356b	430	}