Index · Directives systemd 250


sd_bus_set_address, sd_bus_get_address, sd_bus_set_exec — Set or query the address of the bus connection


#include <systemd/sd-bus.h>
int sd_bus_set_address(sd_bus *bus,
 const char *address);
int sd_bus_get_address(sd_bus *bus,
 const char **address);
int sd_bus_set_exec(sd_bus *bus,
 const char *path,
 char *const *argv);


sd_bus_set_address() configures a list of addresses of bus brokers to try to connect to from a subsequent sd_bus_start(3) call. The argument is a ";"-separated list of addresses to try. Each item must be one of the following:

  • A unix socket address specified as "unix:guid=guid,path=path" or "unix:guid=guid,abstract=path". Exactly one of the path= and abstract= keys must be present, while guid= is optional.

  • A TCP socket address specified as "tcp:[guid=guid,][host=host][,port=port][,family=family]". One or both of the host= and port= keys must be present, while the rest is optional. family may be either ipv4 or ipv6.

  • An executable to spawn specified as "unixexec:guid=guid,path=path,argv1=argument,argv2=argument,...". The path= key must be present, while guid= is optional.

  • A machine (container) to connect to specified as "x-machine-unix:guid=guid,machine=machine,pid=pid". Exactly one of the machine= and pid= keys must be present, while guid= is optional. machine is the name of a local container. See machinectl(1) for more information about the "machine" concept. "" may be used to specify the host machine. A connection to the standard system bus socket inside of the specified machine will be created.

In all cases, parameter guid is an identifier of the remote peer, in the syntax accepted by sd_id128_from_string(3). If specified, the identifier returned by the peer after the connection is established will be checked and the connection will be rejected in case of a mismatch.

Note that the addresses passed to sd_bus_set_address() may not be verified immediately. If they are invalid, an error may be returned e.g. from a subsequent call to sd_bus_start(3).

sd_bus_get_address() returns any previously set addresses. In addition to being explicitly set by sd_bus_set_address(), the address will also be set automatically by sd_bus_open(3) and similar calls, based on environment variables or built-in defaults.

sd_bus_set_exec() is a shorthand function for setting a "unixexec" address that spawns the given executable with the given arguments. If argv is NULL, the given executable is spawned without any extra arguments.

Return Value

On success, these functions return a non-negative integer. On failure, they return a negative errno-style error code.


Returned errors may indicate the following problems:


The input parameters bus or address are NULL.


The bus object bus could not be resolved.


The input parameter bus is in a wrong state (sd_bus_set_address() may only be called once on a newly-created bus object).


The bus object bus was created in a different process.


The bus object bus has no address configured.


These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.

See Also

systemd(1), sd-bus(3), sd_bus_new(3), sd_bus_start(3), systemd-machined.service(8), machinectl(1)