Путеводитель по Руководству Linux

  User  |  Syst  |  Libr  |  Device  |  Files  |  Other  |  Admin  |  Head  |



   sd_uid_get_display    ( 3 )

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)