Abstract sockets have one limitation: they are bound to a network
namespace. Chromium/CEF sandboxes using a new netns, which breaks
connecting to the FEXServer.
To work around this, use and try *both* abstract and named sockets. As
long as either the filesystem or the network is unsandboxed, things will
work. If both are sandboxed, there isn't much we can do... but at that
point we shouldn't be reinitializing the FEXServer connection anyway
since the FS should be available on FEXInterpreter startup.
This was a bit confusing to read and I had always expected to change
this at some point.
Previous:
```
[INFO][1579518391560577][1601857.1601857] clone: Unsupported flags w/o CLONE_THREAD (Shared Resources), 4100
```
Now:
```
[INFO][1590468.992593376][1629501.1629501] clone: Unsupported flags w/o CLONE_THREAD (Shared Resources), 4100
```
Using the server mount folder works most of the time, but when running
under pressure-vessel this stacks directories in a weird way because the
mount folder has some tricks applied to it.
Expose the temp folder being used directly instead.
On first FEXInterpreter execution, it is expected that `ConnectToServer`
will fail with `ECONNREFUSED` because FEXServer won't be running.
Skip printing this first messaage to stderr if configured.
If it is some other error message then ensure it is still printed.
Two changes here.
- Make the mount path follow server temp folder requirements.
- Will be mounted in `/tmp/` or `$XDG_RUNTIME_DIR/` now
- Switch the FEXServer socket to an "abstract" AF_UNIX socket.
- If the socket is in `/tmp/` then systemd will put the service in a
private `/tmp` folder that only exists for the service.
- If the socket is in `$XDG_RUNTIME_DIR` then pressure-vessel can't
chroot anymore since they make their own runtime directory.
- If it is in `$HOME/.fex-emu/` then it breaks usage where the
filesystem is a mount that doesn't support AF_UNIX like sshfs.
The only reasonable thing to do is to switch over to `abstract` sockets
which will work in all cases.
Tested with pressure-vessel and systemd and now it works in all
situations.
It can be useful to know in tooling when the current active FEXServer
has exited.
Two things can happen when this command is run.
No FEXServer is active, returns immediately.
A FEXServer is active, we query for a pidfd from the active server, then
we wait until it exits.
Both instances of this is valid to use.
This is a relatively invasive change since multiple things needed to
happen at once.
* Socket based logging is removed
* Logging has been replaced to only support stdout, stderr, and server
* Server is now default and replaces what FEXLogServer did
* Server logging now uses a pipe instead of a socket
* Can be faster than stderr and stdout since the application doesn't
need to wait on terminal output
* FEXMountDaemon has been removed
* Functionality has been merged in to FEXServer
* FEXServer is always executed on FEX initialization time
* Similar in behaviour to Wine's wineserver
* Can explicitly start this before using FEX for logging purposes
* Stays around until all instances of FEX exit
* Will stick around for a short amount of time in case of spurious
execution
* FEXServer will soon be extended to do more than logging and squashfs
mounting
* FEX rootfs scripts will need to be updated to support this path
* Just means rbinding the /tmp folder and forcing a FEXServer instance
to be alive
* Pressure-vessel works fine in this case since FEXServer will already
be running
* It already rbinds the host /tmp folder which is why this works
Ryan Houdek