FS 10.0.0 fsserver Changes

The first major change is that the server now only needs to use one socket when using websockets — addresses that start with ws:// (closing #29).

The new default base URL for all fsserver streams and control channels is now:

(70 83 are decimal ASCII encoding of F and S.)

This can be changed by editing FS_SERVER_URL_BASE in include/params.h; however, we will likely introduce command-line flag and/or environment variable to set this in the future.

This should be safe to expose on the network (rather than just the loop-back), but users may wish to use HTTPS proxying to provide some authentication/authorisation.

This was enabled by factoring out functionality spub into a reusable “buffered stream” library, which has been incorporated into fsserver. All the behaviour of streams are now managed within the fsserver process rather than an external spub instance.

The second major change of this patch is the addition of the FS log to the streams available from the server (closing #25).

Previously only the “display” was available, which has a reduced time-stamp format and filters some output. The log stream is available at

that is, by default

As of FS 10.2, this change has been reverted, i.e., the server will now shutdown on FS termination. For more information, please see the change Server shutdown in the FS 10.2-alpha2 Update Notes document.

The remainder of this subsection (in the grey shaded box) is relevant only for FS versions 10.0 and 10.1.

As of FS 10.2, the server shuts down when the FS is terminated. An interlock was introduced to prevent termination if it would also stop active autoftp and/or fs.prompt instances. A variable wait was introduced for FS startup to make sure the server has fully shutdown before starting it again. The maximum wait is two seconds. There is no wait unless the FS was restarted faster than that.

Fourth, the server can now accept snap commands to be sent to FS, e.g.:

This allows clients to interact with the FS directly through fsserver rather than needing access to inject_snap.

No filtering or authorisation is implemented on this command channel, so it effectively allows complete command execution privileges in the FS context to anyone with access to the socket. Note this is also true for inject_snap on a standard system. If a station wishes to limit local access they can use iptables/nftables, or use the server in UNIX socket mode and use file system permissions. Stations that would like to enable remote access should implement their own authentication/authorisation that suits their needs, e.g. SSH port forwarding or HTTPS proxying.

The fifth and final major change is that this patch also upgrades the included messaging library nng to version 1.3.0. This brings with it some performance improvements and bug fixes.

Thanks to Jon Quick (HartRAO) for special effort fixing the Makefile for FSL8. He also added documentation file third_party/src/README_nng.make to assist with future upgrades of nng.