SD_UID_GET_STATE(3) sd_uid_get_state SD_UID_GET_STATE(3)NAME
sd_uid_get_state, sd_uid_is_on_seat, sd_uid_get_sessions,
sd_uid_get_seats - Determine login state of a specific Unix user ID
SYNOPSIS
#include <systemd/sd-login.h>
int sd_uid_get_state(uid_t pid, char** state);
int sd_uid_is_on_seat(uid_t pid, int require_active, const char* seat);
int sd_uid_get_sessions(uid_t pid, int require_active,
char*** sessions);
int sd_uid_get_seats(uid_t pid, int require_active, char*** seats);
DESCRIPTIONsd_uid_get_state() may be used to determine the login state of a
specific Unix user identifier. The following states are currently
known: offline (user not logged in at all), lingering (user not logged
in, but some user services running), online (user logged in, but not
active), active (user logged in on an active seat). In the future
additional states might be defined, client code should be written to be
robust in regards to additional state strings being returned. The
returned string needs to be freed with the libc free(3) call after use.
sd_uid_is_on_seat() may be used to determine whether a specific user is
logged in or active on a specific seat. Accepts a Unix user identifier
and a seat identifier string as parameters. The require_active
parameter is a boolean. If non-zero (true) this function will test if
the user is active (i.e. has a session that is in the foreground and
accepting user input) on the specified seat, otherwise (false) only if
the user is logged in (and possibly inactive) on the specified seat.
sd_uid_get_sessions() may be used to determine the current sessions of
the specified user. Acceptes a Unix user identifier as parameter. The
require_active boolean parameter controls whether the returned list
shall consist of only those sessions where the user is currently active
(true) or where the user is currently logged in at all, possibly
inactive (false). The call returns a NULL terminated string array of
session identifiers in sessions which needs to be freed by the caller
with the libc free(3) call after use, including all the strings
referenced. If the string array parameter is passed as NULL the array
will not be filled in, but the return code still indicates the number
of current sessions. Note that instead of an empty array NULL may be
returned and should be considered equivalent to an empty array.
Similar, sd_uid_get_seats() may be used to determine the list of seats
on which the user currently has sessions. Similar semantics apply,
however note that the user may have multiple sessions on the same seat
as well as sessions with no attached seat and hence the number of
entries in the returned array may differ from the one returned by
sd_uid_get_sessions().
RETURN VALUE
On success sd_uid_get_state() returns 0 or a positive integer. If the
test succeeds sd_uid_is_on_seat() returns a positive integer, if it
fails 0. sd_uid_get_sessions() and sd_uid_get_seats() return the
number of entries in the returned arrays. On failure, these calls
return a negative errno-style error code.
NOTES
The sd_uid_get_state(), sd_uid_is_on_seat(), sd_uid_get_sessions(), and
sd_uid_get_seats() interfaces are available as shared library, which
can be compiled and linked to with the libsystemd-login pkg-config(1)
file.
SEE ALSOsystemd(1), sd-login(7), sd_pid_get_owner_uid(3)AUTHOR
Lennart Poettering <lennart@poettering.net>
Developer
systemd 05/23/2012 SD_UID_GET_STATE(3)
