sd_bus_set_address - Man Page

Set or query the address of the bus connection

Synopsis

#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.
Note: connections over TCP are made without encryption. Thus, this mode should only be used in specific situations where integrity and confidentiality of the connection is not necessary or is ensured through some other means. For local connections, "unix:" connections should be used instead.
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. "machine=.host" 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() might 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.

Errors

Returned errors may indicate the following problems:

-EINVAL

The input parameters bus or address are NULL.

Added in version 246.

-ENOPKG

The bus object bus could not be resolved.

Added in version 246.

-EPERM

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

Added in version 246.

-ECHILD

The bus object bus was created in a different process.

Added in version 246.

-ENODATA

The bus object bus has no address configured.

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.

All functions listed here are thread-agnostic and only a single thread may operate on a given object at any given time. Different threads may access the same object at different times. Multiple independent objects may be used from different threads in parallel.

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.