NAME
utmp
, wtmp
,
lastlog
—
login records (DEPRECATED)
SYNOPSIS
#include
<utmp.h>
DESCRIPTION
The interfaces in file ⟨utmp.h⟩ are all DEPRECATED and are only provided for compatibility with previous releases of Mac OS X. See pututxline(3) and utmpx(5) for the supported interfaces.
⟨utmp.h⟩ declares the
structures used to record information about current users in the file
utmp
, logins and logouts in the file
wtmp
, and last logins in the file
lastlog
. The time stamps of date changes, shutdowns
and reboots are also logged in the wtmp
file.
These files can grow rapidly on busy systems, daily or weekly rotation is recommended. If any of these files do not exist, it is not created. These files must be created manually and are normally maintained in either the script /etc/daily or the script /etc/weekly. (See cron(8).)
#define _PATH_UTMP "/var/run/utmp" #define _PATH_WTMP "/var/log/wtmp" #define _PATH_LASTLOG "/var/log/lastlog" #define UT_NAMESIZE 8 #define UT_LINESIZE 8 #define UT_HOSTSIZE 16 struct lastlog { time_t ll_time; char ll_line[UT_LINESIZE]; char ll_host[UT_HOSTSIZE]; }; struct utmp { char ut_line[UT_LINESIZE]; char ut_name[UT_NAMESIZE]; char ut_host[UT_HOSTSIZE]; time_t ut_time; };
Each time a user logs in, the
login program looks up the user's UID in
the file lastlog.
If it is found, the timestamp of
the last time the user logged in, the terminal line and the hostname are
written to the standard output. (Providing the login is not
quiet, see
login(1).)
The login program then records the new
login time in the file lastlog
.
After the new lastlog record is written ,
the file utmp
is opened and the
utmp record for the user inserted. This record remains
there until the user logs out at which time it is deleted. The
utmp
file is used by the programs
rwho(1),
users(1),
w(1), and
who(1).
Next, the login program opens
the file wtmp
, and appends the user's
utmp record. The same utmp
record, with an updated time stamp is later appended to the file when the
user logs out. (See launchd(8).) The wtmp
file is used by
the programs last(1) and ac(8).
In the event of a date change, a shutdown or reboot, the following
items are logged in the wtmp
file.
reboot
shutdown
- A system reboot or shutdown has been initiated. The character
‘
~
’ is placed in the field ut_line, andreboot
orshutdown
in the field ut_name. (See shutdown(8) and reboot(8).) date
- The system time has been manually or automatically updated. (See
date(1).)
The command name date is recorded in the
field ut_name. In the field
ut_line, the character
‘
|
’ indicates the time prior to the change, and the character ‘{
’ indicates the new time.
FILES
- /var/run/utmp
- The
utmp file.
- /var/log/wtmp
- The
wtmp file.
- /var/log/lastlog
- The
lastlog file.
SEE ALSO
HISTORY
A utmp
and wtmp
file format appeared in Version 6 AT&T
UNIX. The lastlog
file format appeared in
3.0BSD.