sd_bus_set_server(3) — Linux manual page
SD_BUS_SET_SERVER(3) sd_bus_set_server SD_BUS_SET_SERVER(3)
NAME
sd_bus_set_server, sd_bus_is_server, sd_bus_get_bus_id,
sd_bus_set_bus_client, sd_bus_is_bus_client, sd_bus_set_monitor,
sd_bus_is_monitor - Configure connection mode for a bus object
SYNOPSIS
#include <systemd/sd-bus.h>
int sd_bus_set_server(sd_bus *bus, int b, sd_id128_t id);
int sd_bus_is_server(sd_bus *bus);
int sd_bus_get_bus_id(sd_bus *bus, sd_id128_t *id);
int sd_bus_set_bus_client(sd_bus *bus, int b);
int sd_bus_is_bus_client(sd_bus *bus);
int sd_bus_set_monitor(sd_bus *bus, int b);
int sd_bus_is_monitor(sd_bus *bus);
DESCRIPTION
sd_bus_set_server() configures the bus object as a server for
direct D-Bus connections. b enables/disables the server mode. If
zero, the server mode is disabled. Otherwise, the server mode is
enabled. Configuring a bus object as a server is required to
allow establishing direct connections between two peers without
going via the D-Bus daemon. id must contain a 128-bit integer id
for the server. If clients add a guid field to their D-Bus
address string, the server id must match this guid or the D-Bus
authentication handshake will fail. If no specific id is defined
for the server, sd_id128_randomize(3) can be used to generate a
random id instead.
sd_bus_is_server() returns whether the server mode is enabled for
the given bus object.
sd_bus_get_bus_id() stores the D-Bus server id configured using
sd_bus_set_server() (for server bus objects) or received during
D-Bus authentication (for client bus objects) in id.
sd_bus_set_bus_client() configures the bus object as a D-Bus
daemon client. b enables/disables the client mode. If zero, the
client mode is disabled and the bus object should connect
directly to a D-Bus server. Otherwise, the client mode is enabled
and the bus object should connect to a D-Bus daemon. When
connecting to an existing bus using any of the functions in the
sd_bus_open(3) family of functions or any of the functions in the
sd_bus_default(3) family of functions, the bus object is
automatically configured as a bus client. However, when
connecting to a D-Bus daemon by calling sd_bus_set_address(3)
followed by sd_bus_start(3), the bus object should be manually
configured as a bus client using sd_bus_set_bus_client(). By
default, a bus object is not configured as a D-Bus daemon client.
sd_bus_is_bus_client() returns whether the client mode is
enabled/disabled for the given bus object.
sd_bus_set_monitor() configures the bus object as a D-Bus monitor
object. b enables/disables the monitor mode. If zero, the
monitor mode is disabled. If non-zero, the monitor mode is
enabled. When the monitor mode is enabled, no messages may be
sent via the bus object and it may not expose any objects on the
bus. To start monitoring messages, call the
org.freedesktop.DBus.Monitoring.BecomeMonitor method of the D-Bus
daemon and pass a list of matches indicating which messages to
intercept. See The D-Bus specification[1] for more information.
sd_bus_is_monitor() returns whether the monitor mode is
enabled/disabled for the given bus object.
RETURN VALUE
On success, sd_bus_set_server(), sd_bus_get_bus_id(),
sd_bus_set_bus_client() and sd_bus_set_monitor() return a
non-negative integer. On failure, they return a negative
errno-style error code.
sd_bus_is_server(), sd_bus_is_bus_client() and
sd_bus_is_monitor() return a positive integer when the server or
client mode is enabled, respectively. Otherwise, they return
zero.
Errors
Returned errors may indicate the following problems:
-ECHILD
The bus connection has been created in a different process,
library or module instance.
Added in version 246.
-EPERM
The bus connection has already been started.
Added in version 246.
-ENOPKG
The bus cannot be resolved.
Added in version 246.
-EINVAL
A required parameter was NULL or b was zero and id did not
equal SD_ID128_NULL.
Added in version 246.
-ENOTCONN
The bus is not connected.
Added in version 246.
NOTES
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.
HISTORY
sd_bus_set_server(), sd_bus_is_server(), sd_bus_get_bus_id(),
sd_bus_set_bus_client(), sd_bus_is_bus_client(),
sd_bus_set_monitor(), and sd_bus_is_monitor() were added in
version 246.
SEE ALSO
systemd(1), sd-bus(3)
NOTES
1. The D-Bus specification
https://dbus.freedesktop.org/doc/dbus-specification.html#bus-messages-become-monitor
COLOPHON
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systemd 257~devel SD_BUS_SET_SERVER(3)
Pages that refer to this page: sd-bus(3), sd_bus_add_match(3), systemd.directives(7), systemd.index(7)