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ACCT(5)                       File Formats Manual                      ACCT(5)

     acct - execution accounting file

     #include <sys/acct.h>

     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;

     struct acct {
             char    ac_comm[10];    /* name of command */
             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;         /* memory usage average */
             comp_t  ac_io;          /* count of IO blocks */
             dev_t   ac_tty;         /* controlling tty */
     #define AFORK   0x01            /* forked but not execed */
     #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 */
             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 AHZ     64

     #ifdef KERNEL
     struct vnode    *acctp;

     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, ACORE, and AXSIG.

     The ASU flag is not recorded anymore because with the switch to kauth(9),
     the superuser model is optional and passing the affected process to every
     authorization call in order to record ASU in p_acflag, would require many
     source changes and would not reflect reality because the authorization
     decision might not have been done based on the secmodel_suser(9) model.

     The ACOMPAT flag was never recorded in NetBSD; we could consider setting
     when the a process is running under emulation, but this is not currently

     Both the ASU and the ACOMPAT flags are retained for source compatibility.

     lastcomm(1), acct(2), execve(2), accton(8), sa(8)

     A acct file format appeared in Version 7 AT&T UNIX.

NetBSD 10.99                   November 15, 2021                  NetBSD 10.99