Provided by: systemd_256.5-2ubuntu3.1_amd64 bug

NAME

       varlinkctl - Introspect with and invoke Varlink services

SYNOPSIS

       varlinkctl [OPTIONS...] info ADDRESS

       varlinkctl [OPTIONS...] list-interfaces ADDRESS

       varlinkctl [OPTIONS...] introspect ADDRESS INTERFACE

       varlinkctl [OPTIONS...] call ADDRESS METHOD [ARGUMENTS]

       varlinkctl [OPTIONS...] validate-idl [FILE]

DESCRIPTION

       varlinkctl may be used to introspect and invoke Varlink[1] services.

       Services are referenced by one of the following:

       •   A Varlink service reference starting with the "unix:" string, followed by an absolute AF_UNIX socket
           path, or by "@" and an arbitrary string (the latter for referencing sockets in the abstract
           namespace).

       •   A Varlink service reference starting with the "exec:" string, followed by an absolute path of a
           binary to execute.

       •   A Varlink service reference starting with the "ssh:" string, followed by an SSH host specification,
           followed by ":", followed by an absolute AF_UNIX socket path. (This requires OpenSSH 9.4 or newer on
           the server side, abstract namespace sockets are not supported.)

       For convenience these two simpler (redundant) service address syntaxes are also supported:

       •   A file system path to an AF_UNIX socket, either absolute (i.e. begins with "/") or relative (in which
           case it must begin with "./").

       •   A file system path to an executable, either absolute or relative (as above, must begin with "/",
           resp.  "./").

COMMANDS

       The following commands are understood:

       info ADDRESS
           Show brief information about the specified service, including vendor name and list of implemented
           interfaces. Expects a service address in one of the formats described above.

           Added in version 255.

       list-interfaces ADDRESS
           Show list of interfaces implemented by the specified service. Expects a service address in one of the
           formats described above.

           Added in version 255.

       introspect ADDRESS INTERFACE
           Show interface definition of the specified interface provided by the specified service. Expects a
           service address in one of the formats described above and a Varlink interface name.

           Added in version 255.

       call ADDRESS METHOD [ARGUMENTS]
           Call the specified method of the specified service. Expects a service address in the format described
           above, a fully qualified Varlink method name, and a JSON arguments object. If the arguments object is
           not specified, it is read from STDIN instead. To pass an empty list of parameters, specify the empty
           object "{}".

           The reply parameters are written as JSON object to STDOUT.

           Added in version 255.

       validate-idl [FILE]
           Reads a Varlink interface definition file, parses and validates it, then outputs it with syntax
           highlighting. This checks for syntax and internal consistency of the interface. Expects a file name
           to read the interface definition from. If omitted reads the interface definition from STDIN.

           Added in version 255.

       help
           Show command syntax help.

           Added in version 255.

OPTIONS

       The following options are understood:

       --more
           When used with call: expect multiple method replies. If this flag is set the method call is sent with
           the more flag set, which tells the service to generate multiple replies, if needed. The command
           remains running until the service sends a reply message that indicates it is the last in the series.
           This flag should be set only for method calls that support this mechanism.

           If this mode is enabled output is automatically switched to JSON-SEQ mode, so that individual reply
           objects can be easily discerned.

           Added in version 255.

       --collect
           This is similar to --more but collects all responses in a JSON array, and prints it, rather than in
           JSON_SEQ mode.

           Added in version 256.

       --oneway
           When used with call: do not expect a method reply. If this flag is set the method call is sent with
           the oneway flag set (the command exits immediately after), which tells the service not to generate a
           reply.

           Added in version 255.

       --json=MODE
           Selects the JSON output formatting, one of "pretty" (for nicely indented, colorized output) or
           "short" (for terse output with minimal whitespace and no newlines), defaults to "short".

           Added in version 255.

       -j
           Equivalent to --json=pretty when invoked interactively from a terminal. Otherwise equivalent to
           --json=short, in particular when the output is piped to some other program.

           Added in version 255.

       --no-pager
           Do not pipe output into a pager.

       -h, --help
           Print a short help text and exit.

       --version
           Print a short version string and exit.

EXAMPLES

       Example 1. Investigating a Service

       The following three commands inspect the "io.systemd.Resolve" service implemented by systemd-
       resolved.service(8), listing general service information and implemented interfaces, and then displaying
       the interface definition of its primary interface:

           $ varlinkctl info /run/systemd/resolve/io.systemd.Resolve
               Vendor: The systemd Project
              Product: systemd (systemd-resolved)
              Version: 254 (254-1522-g4790521^)
                  URL: https://systemd.io/
           Interfaces: io.systemd
                       io.systemd.Resolve
                       org.varlink.service
           $ varlinkctl list-interfaces /run/systemd/resolve/io.systemd.Resolve
           io.systemd
           io.systemd.Resolve
           org.varlink.service
           $ varlinkctl introspect /run/systemd/resolve/io.systemd.Resolve io.systemd.Resolve
           interface io.systemd.Resolve
           type ResolvedAddress(
                   ifindex: ?int,
                   ...

       (Interface definition has been truncated in the example above, in the interest of brevity.)

       Example 2. Invoking a Method

       The following command resolves a hostname via systemd-resolved.service(8)'s ResolveHostname method call.

           $ varlinkctl call /run/systemd/resolve/io.systemd.Resolve io.systemd.Resolve.ResolveHostname '{"name":"systemd.io","family":2}' -j
           {
                   "addresses" : [
                           {
                                   "ifindex" : 2,
                                   "family" : 2,
                                   "address" : [
                                           185,
                                           199,
                                           111,
                                           153
                                   ]
                           }
                   ],
                   "name" : "systemd.io",
                   "flags" : 1048577
           }

       Example 3. Investigating a Service Executable

       The following command inspects the /usr/lib/systemd/systemd-pcrextend executable and the IPC APIs it
       provides. It then invokes a method on it:

           # varlinkctl info /usr/lib/systemd/systemd-pcrextend
               Vendor: The systemd Project
              Product: systemd (systemd-pcrextend)
              Version: 254 (254-1536-g97734fb)
                  URL: https://systemd.io/
           Interfaces: io.systemd
                       io.systemd.PCRExtend
                       org.varlink.service
           # varlinkctl introspect /usr/lib/systemd/systemd-pcrextend io.systemd.PCRExtend
           interface io.systemd.PCRExtend

           method Extend(
                   pcr: int,
                   text: ?string,
                   data: ?string
           ) -> ()
           # varlinkctl call /usr/lib/systemd/systemd-pcrextend io.systemd.PCRExtend.Extend '{"pcr":15,"text":"foobar"}'
           {}

SEE ALSO

       busctl(1), Varlink[1]

NOTES

        1. Varlink
           https://varlink.org/