Name
login, logout — write utmp and wtmp entries
Synopsis
#include <utmp.h>
void
login( |
const struct utmp * | ut); |
int
logout( |
const char * | ut_line); |
![[Note]](../stylesheet/note.png) |
Note |
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Link with |
DESCRIPTION
The utmp file records who is currently using the system. The wtmp file records all logins and logouts. See utmp(5).
The function login() takes
the supplied struct
utmp, ut,
and writes it to both the utmp and the wtmp file.
The function logout() clears
the entry in the utmp file again.
GNU Details
More precisely, login()
takes the argument ut struct, fills the field
ut−>ut_type (if
there is such a field) with the value USER_PROCESS, and fills the field
ut−>ut_pid (if
there is such a field) with the process ID of the calling
process. Then it tries to fill the field ut−>ut_line. It
takes the first of stdin,
stdout, stderr that is a tty, and stores the
corresponding pathname minus a possible leading
/dev/ into this field, and
then writes the struct to the utmp file. On the other hand,
if no tty name was found, this field is filled with "???"
and the struct is not written to the utmp file. After this,
the struct is written to the wtmp file.
The logout() function
searches the utmp file for an entry matching the ut_line argument. If a record
is found, it is updated by zeroing out the ut_name and ut_host fields, updating the ut_tv timestamp field and setting
ut_type (if there is such a
field) to DEAD_PROCESS.
RETURN VALUE
The logout() function
returns 1 if the entry was successfully written to the
database, or 0 if an error occurred.
FILES
/var/run/utmp-
user accounting database, configured through
_PATH_UTMPin<paths.h> /var/log/wtmp-
user accounting log file, configured through
_PATH_WTMPin<paths.h>
NOTES
Note that the member ut_user
of struct utmp is
called ut_name in BSD.
Therefore, ut_name is defined as
an alias for ut_user in
<utmp.h>
COLOPHON
This page is part of release 2.79 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
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This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License's references to "object code" and "executables" are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. Derived from text written by Martin Schulze (or taken from glibc.info) and text written by Paul Thompson - both copyright 2002. |