NAME
endutxent
,
getutxent
, getutxid
,
getutxline
, getutxuser
,
pututxline
, setutxdb
,
setutxent
—
user accounting database
functions
LIBRARY
library “libc”
SYNOPSIS
#include
<utmpx.h>
void
endutxent
(void);
struct utmpx *
getutxent
(void);
struct utmpx *
getutxid
(const
struct utmpx *id);
struct utmpx *
getutxline
(const
struct utmpx *line);
struct utmpx *
getutxuser
(const
char *user);
struct utmpx *
pututxline
(const
struct utmpx *utmpx);
int
setutxdb
(int
type, const char
*file);
void
setutxent
(void);
DESCRIPTION
These functions operate on the user accounting database which stores records of various system activities, such as user login and logouts, but also system startups and shutdowns and modifications to the system's clock. The system stores these records in three databases, each having a different purpose:- /var/run/utx.active
- Log of currently active user login sessions. This file is similar to the traditional utmp file. This file only contains process related entries, such as user login and logout records.
- /var/log/utx.lastlogin
- Log of last user login entries per user. This file is similar to the traditional lastlog file. This file only contains user login records for users who have at least logged in once.
- /var/log/utx.log
- Log of all entries, sorted by date of addition. This file is similar to the traditional wtmp file. This file may contain any type of record described below.
Each entry in these databases is defined by the structure
utmpx found in the include file
<utmpx.h>
:
struct utmpx { short ut_type; /* Type of entry. */ struct timeval ut_tv; /* Time entry was made. */ char ut_id[]; /* Record identifier. */ pid_t ut_pid; /* Process ID. */ char ut_user[]; /* User login name. */ char ut_line[]; /* Device name. */ char ut_host[]; /* Remote hostname. */ };
The ut_type field indicates the type of the log entry, which can have one of the following values:
EMPTY
- No valid user accounting information.
BOOT_TIME
- Identifies time of system boot.
SHUTDOWN_TIME
- Identifies time of system shutdown.
OLD_TIME
- Identifies time when system clock changed.
NEW_TIME
- Identifies time after system clock changed.
USER_PROCESS
- Identifies a process.
INIT_PROCESS
- Identifies a process spawned by the init process.
LOGIN_PROCESS
- Identifies the session leader of a logged-in user.
DEAD_PROCESS
- Identifies a session leader who has exited.
Entries of type INIT_PROCESS
and
LOGIN_PROCESS
are not processed by this
implementation.
Other fields inside the structure are:
- ut_tv
- The time the event occurred. This field is used for all types of entries,
except
EMPTY
. - ut_id
- An identifier that is used to refer to the entry. This identifier can be
used to remove or replace a login entry by writing a new entry to the
database containing the same value for ut_id. This
field is only applicable to entries of type
USER_PROCESS
,INIT_PROCESS
,LOGIN_PROCESS
andDEAD_PROCESS
. - ut_pid
- The process identifier of the session leader of the login session. This
field is only applicable to entries of type
USER_PROCESS
,INIT_PROCESS
,LOGIN_PROCESS
andDEAD_PROCESS
. - ut_user
- The user login name corresponding with the login session. This field is
only applicable to entries of type
USER_PROCESS
andINIT_PROCESS
. ForINIT_PROCESS
entries this entry typically contains the name of the login process. - ut_line
- The name of the TTY character device, without the leading
/dev/ prefix, corresponding with the device used
to facilitate the user login session. If no TTY character device is used,
this field is left blank. This field is only applicable to entries of type
USER_PROCESS
andLOGIN_PROCESS
. - ut_host
- The network hostname of the remote system, connecting to perform a user
login. If the user login session is not performed across a network, this
field is left blank. This field is only applicable to entries of type
USER_PROCESS
.
This implementation guarantees all inapplicable fields are discarded. The ut_user, ut_line and ut_host fields of the structure returned by the library functions are also guaranteed to be null-terminated in this implementation.
The
getutxent
()
function can be used to read the next entry from the user accounting
database.
The
getutxid
()
function searches for the next entry in the database of which the behaviour
is based on the ut_type field of
id. If ut_type has a value of
BOOT_TIME
, SHUTDOWN_TIME
,
OLD_TIME
or NEW_TIME
, it
will return the next entry whose ut_type has an equal
value. If ut_type has a value of
USER_PROCESS
, INIT_PROCESS
,
LOGIN_PROCESS
or
DEAD_PROCESS
, it will return the next entry whose
ut_type has one of the previously mentioned values and
whose ut_id is equal.
The
getutxline
()
function searches for the next entry in the database whose
ut_type has a value of
USER_PROCESS
or
LOGIN_PROCESS
and whose
ut_line is equal to the same field in
line.
The
getutxuser
()
function searches for the next entry in the database whose
ut_type has a value of
USER_PROCESS
and whose ut_user
is equal to user.
The previously mentioned functions will
automatically try to open the user accounting database if not already done
so. The
setutxdb
()
and setutxent
() functions allow the database to be
opened manually, causing the offset within the user accounting database to
be rewound. The
endutxent
()
function closes the database.
The
setutxent
()
database always opens the active sessions database. The
setutxdb
() function opens the database identified by
type, whose value is either
UTXDB_ACTIVE
,
UTXDB_LASTLOGIN
or
UTXDB_LOG
. It will open a custom file with filename
file instead of the system-default if
file is not null. Care must be taken that when using a
custom filename, type still has to match with the
actual format, since each database may use its own file format.
The
pututxline
()
function writes record utmpx to the system-default
user accounting databases. The value of ut_type
determines which databases are modified.
Entries of type SHUTDOWN_TIME
,
OLD_TIME
and NEW_TIME
will
only be written to /var/log/utx.log.
Entries of type USER_PROCESS
will also be
written to /var/run/utx.active and
/var/log/utx.lastlogin.
Entries of type DEAD_PROCESS
will only be
written to /var/log/utx.log and
/var/run/utx.active if a corresponding
USER_PROCESS
, INIT_PROCESS
or LOGIN_PROCESS
entry whose
ut_id is equal has been found in the latter.
In addition, entries of type BOOT_TIME
and
SHUTDOWN_TIME
will cause all existing entries in
/var/run/utx.active to be discarded.
All entries whose type has not been mentioned
previously, are discarded by this implementation of
pututxline
().
This implementation also ignores the value of
ut_tv.
RETURN VALUES
The getutxent
(),
getutxid
(), getutxline
(),
and getutxuser
() functions return a pointer to an
utmpx structure that matches the mentioned constraints
on success or NULL
when reaching the end-of-file or
when an error occurs.
The pututxline
() function returns a
pointer to an utmpx structure containing a copy of the
structure written to disk upon success. It returns
NULL
when the provided utmpx
is invalid, or ut_type has a value of
DEAD_PROCESS
and an entry with an identifier with a
value equal to the field ut_id was not found; the
global variable errno is set to indicate the
error.
The setutxdb
() function returns 0 if the
user accounting database was opened successfully. Otherwise, -1 is returned
and the global variable errno is set to indicate the
error.
ERRORS
In addition to the error conditions described in
open(2),
fdopen(3),
fopen(3),
fseek(3), the pututxline
() function can
generate the following errors:
- [
ESRCH
] - The value of ut_type is DEAD_PROCESS, and the process entry could not be found.
- [
EINVAL
] - The value of ut_type is not supported by this implementation.
setutxdb
() function can generate
the following errors:
- [
EINVAL
] - The type argument contains a value not supported by this implementation.
- [
EFTYPE
] - The file format is invalid.
SEE ALSO
last(1), write(1), getpid(2), gettimeofday(2), tty(4), ac(8), newsyslog(8), utx(8)
STANDARDS
The endutxent
(),
getutxent
(), getutxid
(),
getutxline
() and setutxent
()
functions are expected to conform to IEEE Std 1003.1-2008
(“POSIX.1”).
The pututxline
() function deviates from
the standard by writing its records to multiple database files, depending on
its ut_type. This prevents the need for special
utility functions to update the other databases, such as the
updlastlogx
() and updwtmpx
()
functions which are available in other implementations. It also tries to
replace DEAD_PROCESS
entries in the active sessions
database when storing USER_PROCESS
entries and no
entry with the same value for ut_id has been found.
The standard always requires a new entry to be allocated, which could cause
an unbounded growth of the database.
The getutxuser
() and
setutxdb
() functions, the
ut_host field of the utmpx
structure and SHUTDOWN_TIME
are extensions.
HISTORY
These functions appeared in FreeBSD 9.0.
They replaced the <utmp.h>
interface.
AUTHORS
Ed Schouten <ed@FreeBSD.org>