DESCRIPTION
The kernel maintains the following acct information structure for all processes. If a process terminates, and accounting is enabled, the kernel calls the acct(2) function call to prepare and append the record to the accounting file.
/*
* 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_short comp_t;
#define AC_COMM_LEN 16
struct acct {
char ac_comm[AC_COMM_LEN]; /* 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 */
short ac_mem; /* average memory usage */
comp_t ac_io;/* count of IO blocks */
dev_t ac_tty; /* controlling tty */
#define AFORK 0x01 /* forked but not exec’ed */
#define ASU0x02 /* used super-user permissions */
#define ACOMPAT 0x04 /* used compatibility mode */
#define ACORE 0x08 /* dumped core */
#define AXSIG 0x10 /* killed by a signal */
char 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 AHZ64
If a terminated process was created by an execve(2), the name of the executed file (at most ten characters of it) is saved in the field ac_comm and its status is saved by setting one of more of the following flags in ac_flag: AFORK, ACOMPAT, ACORE and ASIG. ASU is no longer supported.
SEE ALSO
acct(2), execve(2), sa(8)
HISTORY
