определить состояние конкретного сеанса (determine state of a specific session)
Имя (Name)
sd_session_is_active, sd_session_is_remote, sd_session_get_state,
sd_session_get_uid, sd_session_get_seat, sd_session_get_service,
sd_session_get_type, sd_session_get_class,
sd_session_get_desktop, sd_session_get_display,
sd_session_get_tty, sd_session_get_vt,
sd_session_get_remote_host, sd_session_get_remote_user -
Determine state of a specific session
Синопсис (Synopsis)
#include <systemd/sd-login.h>
int sd_session_is_active(const char *session);
int sd_session_is_remote(const char *session);
int sd_session_get_state(const char *session, char **state);
int sd_session_get_uid(const char *session, uid_t *uid);
int sd_session_get_seat(const char *session, char **seat);
int sd_session_get_service(const char *session, char **service);
int sd_session_get_type(const char *session, char **type);
int sd_session_get_class(const char *session, char **class);
int sd_session_get_desktop(const char *session, char **desktop);
int sd_session_get_display(const char *session, char **display);
int sd_session_get_remote_host(const char *session,
char **remote_host);
int sd_session_get_remote_user(const char *session,
char **remote_user);
int sd_session_get_tty(const char *session, char **tty);
int sd_session_get_vt(const char *session, unsigned int *vt);
Описание (Description)
sd_session_is_active() may be used to determine whether the
session identified by the specified session identifier is
currently active (i.e. currently in the foreground and available
for user input) or not.
sd_session_is_remote() may be used to determine whether the
session identified by the specified session identifier is a
remote session (i.e. its remote host is known) or not.
sd_session_get_state() may be used to determine the state of the
session identified by the specified session identifier. The
following states are currently known: "online" (session logged
in, but session not active, i.e. not in the foreground), "active"
(session logged in and active, i.e. in the foreground), "closing"
(session nominally logged out, but some processes belonging to it
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. This function is a more
generic version of sd_session_is_active(). The returned string
needs to be freed with the libc free(3) call after use.
sd_session_get_uid() may be used to determine the user identifier
of the Unix user the session identified by the specified session
identifier belongs to.
sd_session_get_seat() may be used to determine the seat
identifier of the seat the session identified by the specified
session identifier belongs to. Note that not all sessions are
attached to a seat, this call will fail (returning -ENODATA) for
them. The returned string needs to be freed with the libc free(3)
call after use.
sd_session_get_service() may be used to determine the name of the
service (as passed during PAM session setup) that registered the
session identified by the specified session identifier. The
returned string needs to be freed with the libc free(3) call
after use.
sd_session_get_type() may be used to determine the type of the
session identified by the specified session identifier. The
returned string is one of "x11", "wayland", "tty", "mir" or
"unspecified" and needs to be freed with the libc free(3) call
after use.
sd_session_get_class() may be used to determine the class of the
session identified by the specified session identifier. The
returned string is one of "user", "greeter", "lock-screen", or
"background" and needs to be freed with the libc free(3) call
after use.
sd_session_get_desktop() may be used to determine the brand of
the desktop running on the session identified by the specified
session identifier. This field can be set freely by desktop
environments and does not follow any special formatting. However,
desktops are strongly recommended to use the same identifiers and
capitalization as for $XDG_CURRENT_DESKTOP, as defined by the
Desktop Entry Specification
sd_session_get_display() may be used to determine the X11 display
of the session identified by the specified session identifier.
The returned string needs to be freed with the libc free(3) call
after use.
sd_session_get_remote_host() may be used to determine the remote
hostname of the session identified by the specified session
identifier. The returned string needs to be freed with the libc
free(3) call after use.
sd_session_get_remote_user() may be used to determine the remote
username of the session identified by the specified session
identifier. The returned string needs to be freed with the libc
free(3) call after use. Note that this value is rarely known to
the system, and even then should not be relied on.
sd_session_get_tty() may be used to determine the TTY device of
the session identified by the specified session identifier. The
returned string needs to be freed with the libc free(3) call
after use.
sd_session_get_vt() may be used to determine the VT number of the
session identified by the specified session identifier. This
function will return an error if the seat does not support VTs.
If the session parameter of any of these functions is passed as
NULL, the operation is executed for the session the calling
process is a member of, if there is any.
Возвращаемое значение (Return value)
If the test succeeds, sd_session_is_active() and
sd_session_is_remote() return a positive integer; if it fails, 0.
On success, sd_session_get_state(), sd_session_get_uid(),
sd_session_get_seat(), sd_session_get_service(),
sd_session_get_type(), sd_session_get_class(),
sd_session_get_display(), sd_session_get_remote_user(),
sd_session_get_remote_host() and sd_session_get_tty() return 0 or
a positive integer. On failure, these calls return a negative
errno-style error code.
Errors
Returned errors may indicate the following problems:
-ENXIO
The specified session does not exist.
-ENODATA
The given field is not specified for the described session.
-EINVAL
An input parameter was invalid (out of range, or NULL, where
that is not accepted).
-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_session(3)
Примечание (Note)
1. Desktop Entry Specification
http://standards.freedesktop.org/desktop-entry-spec/latest/
