Greeter Interface

Greeter Interface — Make a connection to the LightDM daemon and authenticate users

Synopsis

#include <lightdm.h>

void                (*show_message)                     (LightDMGreeter *greeter,
                                                         const gchar *text,
                                                         LightDMMessageType type);
void                (*show_prompt)                      (LightDMGreeter *greeter,
                                                         const gchar *text,
                                                         LightDMPromptType type);
void                (*authentication_complete)          (LightDMGreeter *greeter);
void                (*autologin_timer_expired)          (LightDMGreeter *greeter);
enum                LightDMMessageType;
enum                LightDMPromptType;
LightDMGreeter *    lightdm_greeter_new                 (void);
gboolean            lightdm_greeter_connect_sync        (LightDMGreeter *greeter,
                                                         GError **error);
gchar *             lightdm_greeter_ensure_shared_data_dir_sync
                                                        (LightDMGreeter *greeter,
                                                         const gchar *username);
const gchar *       lightdm_greeter_get_default_session_hint
                                                        (LightDMGreeter *greeter);
const gchar *       lightdm_greeter_get_hint            (LightDMGreeter *greeter,
                                                         const gchar *name);
gboolean            lightdm_greeter_get_lock_hint       (LightDMGreeter *greeter);
gboolean            lightdm_greeter_get_has_guest_account_hint
                                                        (LightDMGreeter *greeter);
gboolean            lightdm_greeter_get_hide_users_hint (LightDMGreeter *greeter);
gboolean            lightdm_greeter_get_show_manual_login_hint
                                                        (LightDMGreeter *greeter);
gboolean            lightdm_greeter_get_show_remote_login_hint
                                                        (LightDMGreeter *greeter);
const gchar *       lightdm_greeter_get_select_user_hint
                                                        (LightDMGreeter *greeter);
gboolean            lightdm_greeter_get_select_guest_hint
                                                        (LightDMGreeter *greeter);
const gchar *       lightdm_greeter_get_autologin_user_hint
                                                        (LightDMGreeter *greeter);
gboolean            lightdm_greeter_get_autologin_guest_hint
                                                        (LightDMGreeter *greeter);
gint                lightdm_greeter_get_autologin_timeout_hint
                                                        (LightDMGreeter *greeter);
void                lightdm_greeter_set_language        (LightDMGreeter *greeter,
                                                         const gchar *language);
void                lightdm_greeter_cancel_autologin    (LightDMGreeter *greeter);
void                lightdm_greeter_authenticate        (LightDMGreeter *greeter,
                                                         const gchar *username);
void                lightdm_greeter_authenticate_as_guest
                                                        (LightDMGreeter *greeter);
void                lightdm_greeter_authenticate_autologin
                                                        (LightDMGreeter *greeter);
void                lightdm_greeter_authenticate_remote (LightDMGreeter *greeter,
                                                         const gchar *session,
                                                         const gchar *username);
void                lightdm_greeter_respond             (LightDMGreeter *greeter,
                                                         const gchar *response);
void                lightdm_greeter_cancel_authentication
                                                        (LightDMGreeter *greeter);
gboolean            lightdm_greeter_get_in_authentication
                                                        (LightDMGreeter *greeter);
gboolean            lightdm_greeter_get_is_authenticated
                                                        (LightDMGreeter *greeter);
const gchar *       lightdm_greeter_get_authentication_user
                                                        (LightDMGreeter *greeter);
gboolean            lightdm_greeter_start_session_sync  (LightDMGreeter *greeter,
                                                         const gchar *session,
                                                         GError **error);

Description

LightDMGreeter is an object that manages the connection to the LightDM server and provides common greeter functionality.

Example 1. Example Greeter

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int main ()
{
    GMainLoop *main_loop;
    LightDMGreeter *greeter
    main_loop = g_main_loop_new ();
    greeter = lightdm_greeter_new ();
    g_object_connect (greeter, "show-prompt", G_CALLBACK (show_prompt_cb), NULL);
    g_object_connect (greeter, "authentication-complete", G_CALLBACK (authentication_complete_cb), NULL);
    // Connect to LightDM daemon
    if (!lightdm_greeter_connect_sync (greeter, NULL))
        return EXIT_FAILURE;
    // Start authentication
    lightdm_greeter_authenticate (greeter, NULL);
    g_main_loop_run (main_loop);
    return EXIT_SUCCESS;
}
static void show_prompt_cb (LightDMGreeter *greeter, const char *text, LightDMPromptType type)
{
    // Show the user the message and prompt for some response
    gchar *secret = prompt_user (text, type);
    // Give the result to the user
    lightdm_greeter_respond (greeter, response);
}
static void authentication_complete_cb (LightDMGreeter *greeter)
{
    // Start the session
    if (!lightdm_greeter_get_is_authenticated (greeter) ||
        !lightdm_greeter_start_session_sync (greeter, NULL))
    {
        // Failed authentication, try again
        lightdm_greeter_authenticate (greeter, NULL);
    }
}


Details

show_message ()

void                (*show_message)                     (LightDMGreeter *greeter,
                                                         const gchar *text,
                                                         LightDMMessageType type);


show_prompt ()

void                (*show_prompt)                      (LightDMGreeter *greeter,
                                                         const gchar *text,
                                                         LightDMPromptType type);


authentication_complete ()

void                (*authentication_complete)          (LightDMGreeter *greeter);


autologin_timer_expired ()

void                (*autologin_timer_expired)          (LightDMGreeter *greeter);


enum LightDMMessageType

typedef enum {
    LIGHTDM_MESSAGE_TYPE_INFO,
    LIGHTDM_MESSAGE_TYPE_ERROR
} LightDMMessageType;

LIGHTDM_MESSAGE_TYPE_INFO

Informational message.

LIGHTDM_MESSAGE_TYPE_ERROR

Error message.

enum LightDMPromptType

typedef enum {
    LIGHTDM_PROMPT_TYPE_QUESTION,
    LIGHTDM_PROMPT_TYPE_SECRET
} LightDMPromptType;

LIGHTDM_PROMPT_TYPE_QUESTION

Prompt is a question. The information can be shown as it is entered.

LIGHTDM_PROMPT_TYPE_SECRET

Prompt is for secret information. The entered information should be obscured so it can't be publically visible.

lightdm_greeter_new ()

LightDMGreeter *    lightdm_greeter_new                 (void);

Create a new greeter.

Returns :

the new LightDMGreeter

lightdm_greeter_connect_sync ()

gboolean            lightdm_greeter_connect_sync        (LightDMGreeter *greeter,
                                                         GError **error);

Connects the greeter to the display manager. Will block until connected.

greeter :

The greeter to connect

error :

return location for a GError, or NULL

Returns :

TRUE if successfully connected

lightdm_greeter_ensure_shared_data_dir_sync ()

gchar *             lightdm_greeter_ensure_shared_data_dir_sync
                                                        (LightDMGreeter *greeter,
                                                         const gchar *username);

Ensure that a shared data dir for the given user is available. Both the greeter user and username will have write access to that folder. The intention is that larger pieces of shared data would be stored there (files that the greeter creates but wants to give to a user -- like camera photos -- or files that the user creates but wants the greeter to see -- like contact avatars).

LightDM will automatically create these if the user actually logs in, so greeters only need to call this method if they want to store something in the directory themselves.

greeter :

A LightDMGreeter

username :

A username

Returns :

The path to the shared directory, free with g_free.

lightdm_greeter_get_default_session_hint ()

const gchar *       lightdm_greeter_get_default_session_hint
                                                        (LightDMGreeter *greeter);

Get the default session to use.

greeter :

A LightDMGreeter

Returns :

The session name

lightdm_greeter_get_hint ()

const gchar *       lightdm_greeter_get_hint            (LightDMGreeter *greeter,
                                                         const gchar *name);

Get a hint.

greeter :

A LightDMGreeter

name :

The hint name to query.

Returns :

The value for this hint or NULL if not set.

lightdm_greeter_get_lock_hint ()

gboolean            lightdm_greeter_get_lock_hint       (LightDMGreeter *greeter);

Check if the greeter is acting as a lock screen.

greeter :

A LightDMGreeter

Returns :

TRUE if the greeter was triggered by locking the seat.

lightdm_greeter_get_has_guest_account_hint ()

gboolean            lightdm_greeter_get_has_guest_account_hint
                                                        (LightDMGreeter *greeter);

Check if guest sessions are supported.

greeter :

A LightDMGreeter

Returns :

TRUE if guest sessions are supported.

lightdm_greeter_get_hide_users_hint ()

gboolean            lightdm_greeter_get_hide_users_hint (LightDMGreeter *greeter);

Check if user accounts should be shown. If this is TRUE then the list of accounts should be taken from LightDMUserList and displayed in the greeter for the user to choose from. Note that this list can be empty and it is recommended you show a method for the user to enter a username manually.

If this option is shown the greeter should only allow these users to be chosen for login unless the manual login hint is set.

greeter :

A LightDMGreeter

Returns :

TRUE if the available users should not be shown.

lightdm_greeter_get_show_manual_login_hint ()

gboolean            lightdm_greeter_get_show_manual_login_hint
                                                        (LightDMGreeter *greeter);

Check if a manual login option should be shown. If set the GUI should provide a way for a username to be entered manually. Without this hint a greeter which is showing a user list can limit logins to only those users.

greeter :

A LightDMGreeter

Returns :

TRUE if a manual login option should be shown.

lightdm_greeter_get_show_remote_login_hint ()

gboolean            lightdm_greeter_get_show_remote_login_hint
                                                        (LightDMGreeter *greeter);

Check if a remote login option should be shown. If set the GUI should provide a way for a user to log into a remote desktop server.

greeter :

A LightDMGreeter

Returns :

TRUE if a remote login option should be shown.

lightdm_greeter_get_select_user_hint ()

const gchar *       lightdm_greeter_get_select_user_hint
                                                        (LightDMGreeter *greeter);

Get the user to select by default.

greeter :

A LightDMGreeter

Returns :

A username

lightdm_greeter_get_select_guest_hint ()

gboolean            lightdm_greeter_get_select_guest_hint
                                                        (LightDMGreeter *greeter);

Check if the guest account should be selected by default.

greeter :

A LightDMGreeter

Returns :

TRUE if the guest account should be selected by default.

lightdm_greeter_get_autologin_user_hint ()

const gchar *       lightdm_greeter_get_autologin_user_hint
                                                        (LightDMGreeter *greeter);

Get the user account to automatically logg into when the timer expires.

greeter :

A LightDMGreeter

Returns :

The user account to automatically log into.

lightdm_greeter_get_autologin_guest_hint ()

gboolean            lightdm_greeter_get_autologin_guest_hint
                                                        (LightDMGreeter *greeter);

Check if the guest account should be automatically logged into when the timer expires.

greeter :

A LightDMGreeter

Returns :

TRUE if the guest account should be automatically logged into.

lightdm_greeter_get_autologin_timeout_hint ()

gint                lightdm_greeter_get_autologin_timeout_hint
                                                        (LightDMGreeter *greeter);

Get the number of seconds to wait before automaitcally logging in.

greeter :

A LightDMGreeter

Returns :

The number of seconds to wait before automatically logging in or 0 for no timeout.

lightdm_greeter_set_language ()

void                lightdm_greeter_set_language        (LightDMGreeter *greeter,
                                                         const gchar *language);

Set the language for the currently authenticated user.

greeter :

A LightDMGreeter

language :

The language to use for this user in the form of a locale specification (e.g. "de_DE.UTF-8").

lightdm_greeter_cancel_autologin ()

void                lightdm_greeter_cancel_autologin    (LightDMGreeter *greeter);

Cancel the automatic login.

greeter :

A LightDMGreeter

lightdm_greeter_authenticate ()

void                lightdm_greeter_authenticate        (LightDMGreeter *greeter,
                                                         const gchar *username);

Starts the authentication procedure for a user.

greeter :

A LightDMGreeter

username :

A username or NULL to prompt for a username. [allow-none]

lightdm_greeter_authenticate_as_guest ()

void                lightdm_greeter_authenticate_as_guest
                                                        (LightDMGreeter *greeter);

Starts the authentication procedure for the guest user.

greeter :

A LightDMGreeter

lightdm_greeter_authenticate_autologin ()

void                lightdm_greeter_authenticate_autologin
                                                        (LightDMGreeter *greeter);

Starts the authentication procedure for the automatic login user.

greeter :

A LightDMGreeter

lightdm_greeter_authenticate_remote ()

void                lightdm_greeter_authenticate_remote (LightDMGreeter *greeter,
                                                         const gchar *session,
                                                         const gchar *username);

Start authentication for a remote session type.

greeter :

A LightDMGreeter

session :

The name of a remote session

username :

A username of NULL to prompt for a username. [allow-none]

lightdm_greeter_respond ()

void                lightdm_greeter_respond             (LightDMGreeter *greeter,
                                                         const gchar *response);

Provide response to a prompt. May be one in a series.

greeter :

A LightDMGreeter

response :

Response to a prompt

lightdm_greeter_cancel_authentication ()

void                lightdm_greeter_cancel_authentication
                                                        (LightDMGreeter *greeter);

Cancel the current user authentication.

greeter :

A LightDMGreeter

lightdm_greeter_get_in_authentication ()

gboolean            lightdm_greeter_get_in_authentication
                                                        (LightDMGreeter *greeter);

Checks if the greeter is in the process of authenticating.

greeter :

A LightDMGreeter

Returns :

TRUE if the greeter is authenticating a user.

lightdm_greeter_get_is_authenticated ()

gboolean            lightdm_greeter_get_is_authenticated
                                                        (LightDMGreeter *greeter);

Checks if the greeter has successfully authenticated.

greeter :

A LightDMGreeter

Returns :

TRUE if the greeter is authenticated for login.

lightdm_greeter_get_authentication_user ()

const gchar *       lightdm_greeter_get_authentication_user
                                                        (LightDMGreeter *greeter);

Get the user that is being authenticated.

greeter :

A LightDMGreeter

Returns :

The username of the authentication user being authenticated or NULL if no authentication in progress.

lightdm_greeter_start_session_sync ()

gboolean            lightdm_greeter_start_session_sync  (LightDMGreeter *greeter,
                                                         const gchar *session,
                                                         GError **error);

Start a session for the authenticated user.

greeter :

A LightDMGreeter

session :

The session to log into or NULL to use the default. [allow-none]

error :

return location for a GError, or NULL

Returns :

TRUE if the session was started.