определить состояние входа в систему для определенного идентификатора пользователя Unix (determine login state of a specific Unix user ID)
Имя (Name)
sd_uid_get_state, sd_uid_is_on_seat, sd_uid_get_sessions,
sd_uid_get_seats, sd_uid_get_display - Determine login state of a
specific Unix user ID
Синопсис (Synopsis)
#include <systemd/sd-login.h>
int sd_uid_get_state(uid_t uid, char **state);
int sd_uid_is_on_seat(uid_t uid, int require_active,
const char *seat);
int sd_uid_get_sessions(uid_t uid, int require_active,
char ***sessions);
int sd_uid_get_seats(uid_t uid, int require_active,
char ***seats);
int sd_uid_get_display(uid_t uid, char **session);
Описание (Description)
sd_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, i.e. has no session in the
foreground), "active" (user logged in, and has at least one
active session, i.e. one session in the foreground), "closing"
(user not logged in, and not lingering, but some processes are
still around). 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 value. 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. Accepts a Unix user identifier as
parameter. The require_active parameter controls whether the
returned list shall consist of only those sessions where the user
is currently active (> 0), where the user is currently online but
possibly inactive (= 0), or logged in at all but possibly closing
the session (< 0). 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.
Similarly, 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().
sd_uid_get_display() returns the name of the "primary" session of
a user. If the user has graphical sessions, it will be the oldest
graphical session. Otherwise, it will be the oldest open session.
Возвращаемое значение (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. sd_uid_get_display() returns a non-negative code on
success. On failure, these calls return a negative errno-style
error code.
Errors
Returned errors may indicate the following problems:
-ENODATA
The given field is not specified for the described user.
-ENXIO
The specified seat is unknown.
-EINVAL
An input parameter was invalid (out of range, or NULL, where
that is not accepted). This is also returned if the passed
user ID is 0xFFFF or 0xFFFFFFFF, which are undefined on
Linux.
-ENOMEM
Memory allocation failed.
Примечание (Note)
These APIs are implemented as a shared library, which can be
compiled and linked to with the libsystemd pkg-config(1) file.
Смотри также (See also)
systemd(1), sd-login(3), sd_pid_get_owner_uid(3)
