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); |
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_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
free(3)
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
free(3)
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
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",
"user-early", "user-light", "user-early-light",
"user-incomplete", "greeter", "lock-screen",
"background", "background-light", "manager" or
"manager-early" 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. The returned string needs to be freed
with the libc
free(3)
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
free(3)
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
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.
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.
Functions described here are available as a shared
library, which can be compiled against and linked to with the
libsystemd pkg-config(1)
file.
The code described here uses
getenv(3),
which is declared to be not multi-thread-safe. This means that the code calling the functions described
here must not call
setenv(3)
from a parallel thread. It is recommended to only do calls to setenv()
from an early phase of the program when no other threads have been started.
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.