This adds a new `ThunksDB.json` file to the config folder.
This file lets users describe thunks in a meaningful way without
duplicating it amongst multiple configuration files.
eg:
```
{
"DB": {
"GL": {
"Library" : "libGL-guest.so",
"Depends": [
"X11"
],
"Overlay": [
"/usr/lib/x86_64-linux-gnu/libGL.so",
"/usr/lib/x86_64-linux-gnu/libGL.so.1",
"/usr/lib/x86_64-linux-gnu/libGL.so.1.2.0",
"/usr/lib/x86_64-linux-gnu/libGL.so.1.7.0",
"/lib/x86_64-linux-gnu/libGL.so",
"/lib/x86_64-linux-gnu/libGL.so.1",
"/lib/x86_64-linux-gnu/libGL.so.1.2.0",
"/lib/x86_64-linux-gnu/libGL.so.1.7.0"
]
},
"X11": {
"Library": "libX11-guest.so",
"Overlay": [
"/usr/lib/x86_64-linux-gnu/libX11.so.6",
"/lib/x86_64-linux-gnu/libX11.so.6"
]
}
}
}
```
This file lets the user describe the library with an nicer name, in this instance
`GL` instead of `libGL-guest.so`.
It also tracks depedencies, like how GL currently has a hard dependency on X11.
This allows the loader to automatically enable the dependencies if described.
The `Overlays` array is like the regular Thunks config file but now in this DB file.
With the DB file now describing the libraries, this allows us to then stick a lighter
description inside of the Thunk Config file.
```
{
"ThunksDB": {
"GL": 1
}
}
```
With this example Thunk config file (Which can be configured per application), There is
a new property of name `ThunksDB`.
All this takes is key:value pairs which describe the user friendly library name and an Integer
to state if the thunk should be enabled or not.
This allows very quick toggling of thunks directly inside of the configuration files rather than
breaking the configuration to disable it.
There was a hard upper limit to 128 json elements, this has now been
removed.
The debugging text for the thunk overlay is now disabled. It can get
very spammy but it is useful for debugging purposes.
Fixes an issue where thunks would be entirely disabled if a RootFS isn't
set.
This meant debugging in a chroot or x86_64 host was breaking rootfs
epoll_pwait has a sigsetsize argument, which was unused in this case but
it caused strace to look ugly.
On epoll_ctl, don't write back the resulting event. The event isn't
written and depending on how the guest allocated the object, we could
have a 4byte overwrite.
Needed to fix rt_sigtimedwait to use the raw syscall.
Needed to have sigtimedwait and sigtimedwait_time64 parse siginfo_t
correctly.
glibc uses this to ensure it is sending the correct signal across from
their helper thread.
Needed to correctly parse sigval and sigevent for 32-bit.
Passes my unit test for timer_create
wine walks the file structure to ensure the cwdir is safe for use. It
does this with a combination of `getcwd` and `statx`.
Once it reachs `/` then in rootfs environments it would fail to find
directories we've deleted.
Thus making it impossible to find folders like `/mnt` and `/home`
Should be safe since it just gives the application a larger world view
In the case of running inside of a container then we need to redirect
where we look for configuration.
Currently we only care about pressure vessel so we just redirect some
options to check inside of `/run/host/`
This will resolve an issue where installed thunks wouldn't be found.
32-bit versions of these syscalls saturate on the upper limit.
Depending on which syscall it'll saturate signed or unsigned.
With set if the 32-bit value is UINT32_MAX then it'll saturate to the
maximum 64-bit value
This solves a problem where sometimes FEX would spin up a new process
while FEXMountDaemon was in the process of shutting down. Breaking
things on both sides.
Now the race conditions are squashed that I could see.
Also fixes one race where FEX is starting up and FEXMountDaemon is
spinning up. This case is where FEX managed to pull the lock file just
before it got deleted. Then sent the FEXMountDaemon a request to be
observed. With DGRAM sockets we would fire and forget. Use a STREAM with
a ack result so we know we can return.
The FEXMountDaemon no longer uses the inotify interface for refcounting
instances of FEX.
The inotify interface fails to send close events when an application
crashes. Which is either an API oversight or intentional choice.
Now to use FEXMountDaemon the FEX process must send the daemon a pipe
fd.
The FEXMountDaemon then uses the write end of the pipe to determine if
the read end of the pipe is still open. It does this using the epoll API
and ref counting how many pipes are still active.
This is possible since epoll will tell us if pipe status has changed to
error. Signalling to the write end that the read end has closed for
whatever reason.
Now we only use the "lock" file to remove races and tell the new
instances of FEX where the rootfs is mounted
Due to how we emulate the guest signal handlers, we do the state setup
in the real host signal handler, then we jump out after state setup.
This was causing a situation where we were setting up the guest signal
handler state with the correct sa_mask.
Then after setting up the guest state we would leave the FEX signal
handler, restoring the signal mask to our original mask.
Instead now as we are setting up the guest state, we save our host
signal mask. Then on signal handler return we modify our host signal
mask to match what the guest wants.
Once we hit our sigreturn emulation we then restore the original signal
mask.
This looks to improve some stability problems regarding how wine uses
signals but it still doesn't fix the gvisor test sadly.
Now that we deparent FEXMountDaemon we can no longer use
PR_SET_PDEATHSIG.
Instead we rely on the ref counting and checking the pipe status to see
if the original parent has left us.
Further improvements that could be done in the future is that every user
of the mount point talks to the daemon to give it a pipe to check is
still live, since the ref counting sometimes is incorrect.
This flag is ignored with sigaltstack.
Fixes an early assert in:
- Splice
- No Time to Explain Remastered
- Ittledew
- Hyperdrive Massacre
- English Country Tune
This allows FEXMountDaemon to remove FEXInterpreter as its parent.
Instead becoming the parent of whatever the current reaper process is.
Do it as early as possible this way FEXInterpreter won't get an
erroneous SIGCHLD.
There is no glibc wrapper for tkill and tgkill requires a tgid.
Kernel will reject us if we tried using -1 or 0 even though that is what
it does internally.
If it is going back to SIG_IGN or SIG_DFL then let them unregister.
This is useful for when they are wanting to ignore a signal after a
while.
Or only capture a fault during a time, then afterwards want the
application to crash on error.
Additionally clears up some other minor logic which wasn't being used
anymore
These syscall arguments are not laid out in a sane way.
Looks like they wanted to keep the interface the same for both x86-64
and 32-bit x86 so they split the offset argument in to two values.
Weirdly enough, even though these are 32-bit offsets on 32-bit x86; On
x86-64 these are still 64-bit. Which means the kernel weirdly allows you
to overlap the two 64-bit halves.
eg: `uint64_t Offset = (pos_high << 32) | pos_low;`
So you can have a 64-bit value that is the full range, but if you have
data in the lower 32-bits of pos_high then you corrupt the offset.
Additionally this allows you to interleave low and high if you want to
be obtuse.
Lioncash