NAME

utmp, wtmp, btmp − utmp, wtmp, btmp entry format

SYNOPSIS

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

DESCRIPTION

These files, which hold user and accounting information for such commands as last, who, write, and login (see last(1), who(1), write(1), and login(1)), have the following structure as defined by <utmp.h>:

#define UTMP_FILE   "/etc/utmp"
#define WTMP_FILE   "/var/adm/wtmp"
#define BTMP_FILE   "/var/adm/btmp"
#define ut_nameut_user
structutmp {
  char   ut_user[8];           /* User login name */
  char   ut_id[4];             /* /etc/inittab id(usually line#)*/
  char   ut_line[12]           /* device name (console, lnxx) */
  pid_t  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.*/
  unsigned short ut_reserved1; /* Reserved for future use*/
  time_t  ut_time;             /* time entry was made*/
  char    ut_host[16];         /* host name,if remote*/
  unsigned long ut_addr;       /* host Internet addr, if remote*/
};
/*  Definitions for ut_type  */
#defineEMPTY0
#defineRUN_LVL1
#defineBOOT_TIME2
#defineOLD_TIME3
#defineNEW_TIME4
#defineINIT_PROCESS5/* Process spawned by "init" */
#defineLOGIN_PROCESS6/* getty process awaiting login */
#defineUSER_PROCESS7/* A user process */
#defineDEAD_PROCESS8
#defineACCOUNTING9
#defineUTMAXTYPEACCOUNTING  /* Max. 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"

File utmp contains a record of all users logged onto the system.  File btmp contains bad login entries for each invalid logon attempt.  File wtmp contains a record of all logins and logouts. 

Note that wtmp and btmp tend to grow without bound, and should be checked regularly.  Information that is no longer useful should be removed periodically to prevent it from becoming too large.  Also note that wtmp and btmp are not created by the programs that maintain them.  Thus, if these files are removed, record-keeping is turned off. 

FILES

/etc/utmp
/var/adm/wtmp
/var/adm/btmp

AUTHOR

utmp, wtmp, and btmp were developed by HP and the University of California, Berkeley. 

SEE ALSO

last(1), login(1), who(1), write(1), acctcon(1M), fwtmp(1M), getut(3C). 

STANDARDS CONFORMANCE

<utmp.h>: XPG2

Hewlett-Packard Company  —  HP-UX Release 10.20:  July 1996