sd_session_is_active
systemd
sd_session_is_active
3
sd_session_is_active
sd_session_is_remote
sd_session_get_state
sd_session_get_uid
sd_session_get_username
sd_session_get_seat
sd_session_get_start_time
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
sd_session_get_leader
Determine state of a specific session
#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_username
const char *session
char **username
int sd_session_get_seat
const char *session
char **seat
int sd_session_get_start_time
const char *session
uint64_t *usec
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_leader
const char *session
pid_t *leader
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
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
free3
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_username() may be used to
determine the name of the Unix user the session identified by
the specified session identifier belongs to. The returned string
needs to be freed with the libc
free3
call after use.
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
free3
call after use.
sd_session_get_start_time() may be used to
determine the start time of the session identified by the specified
session identifier belongs to. The usec
is in microseconds since the epoch (CLOCK_REALTIME).
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
free3
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
free3
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,
user-early, greeter, lock-screen,
background, background-light, manager or
manager-early and needs to be freed with the libc free3 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. The returned string needs to be freed
with the libc
free3
call after use.
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
free3
call after use.
sd_session_get_leader() may be used to
determine the PID of the leader of the session identified by the
specified session identifier.
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
free3
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
free3
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
free3
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.
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_username(),
sd_session_get_seat(),
sd_session_get_service(),
sd_session_get_type(),
sd_session_get_class(),
sd_session_get_display(),
sd_session_get_leader(),
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.
History
sd_session_get_state() was added in version 186.
sd_session_get_tty() was added in version 198.
sd_session_get_vt() was added in version 207.
sd_session_is_remote(),
sd_session_get_remote_host(), and
sd_session_get_remote_user() were added in version 209.
sd_session_get_desktop() was added in version 217.
sd_session_get_username(),
sd_session_get_start_time(), and
sd_session_get_leader() were added in version 254.
See Also
systemd1
sd-login3
sd_pid_get_session3