UTMP(5)                              BSD                               UTMP(5)



NAME
     utmp, wtmp - login records

SYNOPSIS
     #include <utmp.h>
     #include <sys/types.h>

DESCRIPTION
     The utmp file records information about who is currently using the
     system.  The file is a sequence of entries with the following structure
     (declared in <utmp.h>):

     #define UTMP_$NAME_SIZE 32      /* size of user and host names in Apollo utmp files */

     #define UTMP_FILE       "/etc/utmp"
     #define WTMP_FILE       "/etc/wtmp"
     #define ut_name ut_user

     typedef struct {
             unsigned short  family;
             unsigned char   data[14];
     } ut_node_t;

     struct utmp
       {
             char ut_user[UTMP_$NAME_SIZE] ; /* User login name */
             char ut_id[4] ;                 /* /etc/lines id(usually line #) */
             char ut_line[12] ;              /* device name (console, lnxx) */
             short ut_pid ;                  /* process id */
             short ut_type ;                 /* type of entry */
             struct exit_status
               {
                 short e_termination ;       /* Process termination status */
                 short e_exit ;              /* Process exit status */
               }
             ut_exit ;                       /* The exit status of a process
                                              * marked as DEAD_PROCESS.
                                              */
             time_t ut_time ;                /* time entry was made */
             char ut_host[UTMP_$NAME_SIZE] ; /* host name, if remote */
             struct entry_loc                /* new fields for node and boot node info */
             {       ut_node_t       node;
                     ut_node_t       boot_node;
             } ut_loc;
       } ;

     /*      Definitions for ut_type                                         */

     #define EMPTY           0
     #define RUN_LVL         1
     #define BOOT_TIME       2
     #define OLD_TIME        3
     #define NEW_TIME        4
     #define INIT_PROCESS    5       /* Process spawned by "init" */
     #define LOGIN_PROCESS   6       /* A "getty" process waiting for login */
     #define USER_PROCESS    7       /* A user process */
     #define DEAD_PROCESS    8
     #define ACCOUNTING      9

     #define UTMAXTYPE       ACCOUNTING      /* Largest legal value of ut_type */

     /*      Special strings or formats used in the "ut_line" field when     */
     /*      accounting for something other than a process.                  */
     /*      No string for the ut_line field can be more than 11 chars +     */
     /*      a NULL in length.                                               */

     #define RUNLVL_MSG      "run-level %c"
     #define BOOT_MSG        "system boot"
     #define OTIME_MSG       "old time"
     #define NTIME_MSG       "new time"

     This structure gives the name of the special file associated with the
     user's terminal, the user's log-in name, and the time of the log-in in
     the form of time(3C).

     These files hold user and accounting information for such commands as
     who(1), write(1), and login(1).

     Wtmp is maintained by login(1) and init(8).  Neither of these programs
     creates the file, so if it is removed record-keeping is turned off.  It
     is summarized by ac(8).

FILES
     /etc/utmp
     /usr/adm/wtmp

SEE ALSO
     login(1), init(8), who(1), ac(8)