.\"	$OpenBSD: acct.5,v 1.13 2010/11/01 22:07:08 jmc Exp $
.\"	$NetBSD: acct.5,v 1.4 1995/10/22 01:40:10 ghudson Exp $
.\"
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.\"     @(#)acct.5	8.1 (Berkeley) 6/5/93
.\"
.Dd $Mdocdate: November 1 2010 $
.Dt ACCT 5
.Os
.Sh NAME
.Nm acct
.Nd execution accounting file
.Sh SYNOPSIS
.Fd #include <sys/acct.h>
.Sh DESCRIPTION
The kernel maintains the following
.Fa acct
information structure for all
processes.
If a process terminates, and accounting is enabled, the kernel calls the
.Xr acct 2
function call to prepare and append the record
to the accounting file.
.Bd -literal
/*
 * Accounting structures; these use a comp_t type which is a 3 bits base 8
 * exponent, 13 bit fraction ``floating point'' number.  Units are 1/AHZ
 * seconds.
 */
typedef u_int16_t comp_t;

struct acct {
	char	  ac_comm[10];	/* command name */
	comp_t	  ac_utime;	/* user time */
	comp_t	  ac_stime;	/* system time */
	comp_t	  ac_etime;	/* elapsed time */
	time_t	  ac_btime;	/* starting time */
	uid_t	  ac_uid;	/* user id */
	gid_t	  ac_gid;	/* group id */
	u_int16_t ac_mem;	/* average memory usage */
	comp_t	  ac_io;	/* count of IO blocks */
	dev_t	  ac_tty;	/* controlling tty */

#define	AFORK	0x01		/* fork'd but not exec'd */
#define	ASU	0x02		/* used super-user permissions */
#define	ACOMPAT	0x04		/* used compatibility mode */
#define	ACORE	0x08		/* dumped core */
#define	AXSIG	0x10		/* killed by a signal */
	u_int8_t  ac_flag;	/* accounting flags */
};

/*
 * 1/AHZ is the granularity of the data encoded in the comp_t fields.
 * This is not necessarily equal to hz.
 */
#define	AHZ	64

#ifdef _KERNEL
int	acct_process(struct proc *p);
#endif
.Ed
.Pp
If a terminated process was created by an
.Xr execve 2 ,
the name of the executed file (at most ten characters of it)
is saved in the field
.Fa ac_comm
and its status is saved by setting one or more of the following flags in
.Fa ac_flag :
.Dv AFORK ,
.Dv ASU ,
.Dv ACOMPAT ,
.Dv ACORE ,
and
.Dv AXSIG .
.Sh SEE ALSO
.Xr lastcomm 1 ,
.Xr acct 2 ,
.Xr execve 2 ,
.Xr accton 8 ,
.Xr sa 8
.Sh HISTORY
An
.Nm
file format first appeared in
.At v7 .