Performance stats up front:
This improves pressure-vessel startup time on my test device by 10.1%
Improving the startup time from 9.71425 seconds to 8.7421 seconds.
Most filesystem based syscalls support a file descriptor version with an
*at suffix. This allows us to do these syscalls with pathnames that are
relative to the directory FD that is passed to the syscall.
This is pretty much exactly what we want when we are searching for files
inside of our rootfs. The only quirk ends up being that we are getting
passed absolute paths. This ends up being very simple to workaround by
stripping off the front '/' character. Doing this is just offsetting the
pointer passed to the syscall by one byte.
This does require having two temporary buffers of size PATH_MAX passed
to the handler since just like in the other implementation, we need to
keep the previous result around. The difference being now that we aren't
doing a bunch of std::string temporary manipulation and now we are
returning one of the passed in buffers back depending on the result.
This has been a long time coming. The C interface has been a thorn in
our side for no reason for a long time.
The purpose of this step is to remove the C interface without changing
behaviour as much as possible. This means that with this commit there
are still some bad practices but the remaining issues will be solved
with followup PRs.
Primarily, we still have a `DestroyContext(CTX)` static function which calls
the Context implementation's `DestroyContext` and does a raw C++ delete.
Follow up PR will remove that, but I didn't want to touch it yet since
it'll require checking to ensure the unique_ptr changes play nice with
our allocator hooking. Which this is already a huge PR without trying to
change behaviour.
`GetEmulatedPath` and `OpenAt` are called a /lot/ in applications.
std::filesystem::path handling here is quite heavy and costly for what
we are trying to achieve.
Remove this usage and instead use lstat, access, and readlink directly
which is a heck of a lot faster.
In particular this helps out pressure-vessel, shaving off launch times
by 1-2 seconds.
Going from ~22 seconds down to ~20 seconds.
This will be useful for keying specific executables to steamids.
This is sadly required because a bunch of games end up naming themselves
"game.exe" so we can't safely enable thunks for all things shipping a
generic name.
Previously the config options could only have ever enabled thunks rather than
disable them.
Now sort the code so it can enable thunks, then following configs can
redisable them. Allowing testing with global thunks enabled and
disabling problematic applications.
Also sorts the "ThunkConfigFile" config as lower priority than the
application configs. I wasn't thinking about ordering that hard for
these five configuration paths, but application configs should be higher
priority in this case.
Previously in order to enable thunks, we needed an independent
description file of which thunks to be enabled. This is nice for quickly
testing out new games by setting `FEX_THUNKCONFIG` environment variable.
For users that just want to enable thunks this is an unwieldy
indirection that doesn't make much sense at a glance.
Previously this meant you needed two files as an example:
```
ryanh@ubuntu-linux-20-04-desktop:~/.fex-emu$ cat thunks.json
{
"ThunksDB": {
"GL": 1,
"Vulkan": 1
}
}
ryanh@ubuntu-linux-20-04-desktop:~/.fex-emu$ cat AppConfig/EnderLiliesSteam-Linux-Shipping.json
{
"Config": {
"ThunkConfig":"~\/.fex-emu\/thunks.json"
}
}
```
Instead of this unwieldy redirection just support `ThunksDB` json
directly in the AppConfig.
```
ryanh@ubuntu-linux-20-04-desktop:~/.fex-emu$ cat AppConfig/EnderLiliesSteam-Linux-Shipping.json
{
"Config": {
<...>
},
"ThunksDB": {
"GL": 1,
"Vulkan": 1
}
}
```
As can be seen this makes this significantly easier for new users
getting in to thunks. Depending on which path to enable thunks the user
is more comfortable with, they can still enable them using the
`ThunkConfig` option or embedding directly in the application
configuration.
Additionally this removes the older non-ThunksDB path to loading thunks.
All users of it have moved on to using ThunksDB.
It's common for Linux applications that use close_range to pass in ~0 as
the last FD. This was causing FEX to spin from [2, ~0U] in this loop.
This would take /forever/ to run.
Change over to an ordered map and use the map's range searching and
ranged erase to more quickly remove these elements.
Fixes a hang that occurs with first time Steam setup in
steam-linux-runtime heavy application `steam-runtime-identify-library-abi`.
Currently thunk prefixes are mutally exclusive. No thunks database path
can currently have more than one prefix. If this is necessary then we
can add it in the future.
Most minor of optimizations here, we only scan the string once to find a
prefix, instead of searching for it on all four prefix replacements.
std::filesystem::canonical is very heavyweight and walks the full path
to ensure that each folder in the path is not a symlink.
eg:
```
readlink("/proc", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/proc/self", "880556", 1023) = 6
readlink("/proc/880556", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/proc/880556/fd", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/proc/880556/fd/5", "/home/ryanh/.fex-emu/RootFS/Ubuntu_22_04/usr/lib/x86_64-linux-gnu/ld-linux-x86-6"..., 1023) = 86
readlink("/home", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/home/ryanh", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/home/ryanh/.fex-emu", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/home/ryanh/.fex-emu/RootFS", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/home/ryanh/.fex-emu/RootFS/Ubuntu_22_04", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/home/ryanh/.fex-emu/RootFS/Ubuntu_22_04/usr", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/home/ryanh/.fex-emu/RootFS/Ubuntu_22_04/usr/lib", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/home/ryanh/.fex-emu/RootFS/Ubuntu_22_04/usr/lib/x86_64-linux-gnu", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
readlink("/home/ryanh/.fex-emu/RootFS/Ubuntu_22_04/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2", 0x7ffd5646e210, 1023) = -1 EINVAL (Invalid argument)
```
This is what was occuring for every single mmap that occurs. /really/
adding to the time for the syscall to take.
This also happens on a couple of other syscalls which are using this new
path now.
The primary reason why this works is that we know that every entry in
`/proc/self/fd/` is a symlink. So instead of asking for canonical, we
can just read the symlink and this will redirect us to the canonical
path.
So this previous example goes from 14 syscalls down to 1.
eg:
```
readlinkat(AT_FDCWD, "/proc/self/fd/5", "/home/ryanh/.fex-emu/RootFS/Ubuntu_22_04/usr/lib/x86_64-linux-gnu/ld-linux-x86-6"..., 4096) = 86
```
While this is only a minor improvement in the "typical" operating environment,
this significantly improves performance of FEX under proot or if the
rootfs lives on a network share.
Instead of duplicating prefixes in the ThunksDB json file even more,
just do a prefix replacement when the thunks database is being parsed.
Changes the JSON overlay arrays over to @PREFIX@ and reduce the
duplication.
Adds support for the pressure-vessel prefix `/usr/lib/pressure-vessel/overrides/lib`
This gets thunks ready for running under pressure-vessel, once vulkan
thunking switches from device libraries to the vulkan loader it should
just work.
open is rarely used compared to openat and openat2, so this has been
just missed but nothing really got upset about it.
Fixes Proton Experimental while running under pressure-vessel.
Some syscalls support `AT_SYMLINK_NOFOLLOW` In these instances we need
to follow the symlink on a couple of syscalls.
Fixes executing wine using the basic wine path
eg:
FEXBash "wine dxcapsviewer.exe"
Adds a header only include utility folder that can be included from
everywhere.
Contains syscall helpers for older glibc and defines for older Linux
uapi headers missing some defines.
Migrates lingering instances of the old logger over to fmt where
applicable. This allows removing some of the old defines and functions.
The only remaining usages of the printf-based variant of the logger is
in Tests/LinuxSyscalls/Syscalls.cpp for the strace handling.
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
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
This isn't quite a 100% clean sweep of IWYU.
There are some false positives where clang fails.
Additionally there are still a few missed in the frontend side of things
that I didn't get to
Similar code to readlinkat. Needs to be correct for self otherwise we
return EINVAL which is unexpected since self should always be a symlink
Fixes a bug in running bwrap
This fixes an issue where rootfs has symlinks to other things in the rootfs so we need to track it through.
Relies on #1009 to be merged first.
Fixes any application that relies on libblas, mpv for example.
Ryan Houdek