static-pie is crashing early due to an issue with pthread symbols being exposed as weak.
For some reason the weak symbols never get resolved and jump to zero or ELF base.
When linking static-pie, force search for the pthread symbols using an undefined glob.
With this, static-pie works as long as you link with a new enough version of lld (version 13.0)
This lets us support the final two flags in binfmt_misc that we needed.
1) Support open_binary
2) Support preserve
1)
We already supported the credentials flag, which implied open_binary, but we weren't handling half of it.
With the open_binary flag, the Linux kernel passes us the executable in an FD instead of as a pathname.
This can be found inside of auxv on startup, inside of AT_EXECFD.
If AT_EXECFD is available then we prioritize using that instead of the pathname passed in.
This fixes a potential permissions issue where an executable is executed without read permissions.
2)
The preserve flag has the Linux kernel preserve the original argv[0] that was passed to the application.
Prior to supporting this flag, the kernel would provide us with a resolved program path.
This can happen in the instance where something like `blah` resolves to `/usr/loca/bin/blah` which
isn't what the user originally typed.
This works around this problem by handing the interpreter both the resolved path and the original typed path.
Alongside open_binary, we can just use the FD passed in instead of the resolved path, this means
we can just drop the argv[0] for the guest (which is the kernel resolved path) and pass through arguments
unmangled.
We do have to make a minor assumption here that if we are using EXECFD that we assume preserve.
It isn't until kernel v5.12 that we can actually check AT_FLAGS to see if that was true.
We had hardcoded paths in our binfmt_misc files. Change it to a generated
file instead.
Additionally for the binfmt_misc install targets, since we aren't installing to the
global binfmt_misc folder, we need to pass in the import directory
Fixes#1169
The SyscallHandler takes over ownership of BRK from the ELFLoader.
We were failing to deallocate the full range.
Additionally if the guest changed BRK size to something smaller than initial load then the size would underflow.
This option does cmake checks to determine if your system can handle static-pie.
With upstream projects static-pie only works if you use the binutils linker.
Using lld doesn't currently work because it defines __rela_iplt_{start,end} symbols.
Our cmake file will now compile a test application and check for these symbols.
Either the symbols will not exist at all or they will exist but be a null address
Once your system passes the checks then it will allow you to enable static-pie
In the case that there is an immediate configuration failure. Use stderr specifically for outputting.
These errors won't be output typically because silent logging is enabled by default.
In the case of executable missing or rootfs configuration failure, print directly to stderr.
Previously it looked like FEX just exited for no reason.
We had multiple users encounter this and be confused
We already support receiving user signals in our signal handlers for this.
Just need to push through syscalls.
This fixes Dead Island Definitive Edition so it runs.
This is a base implementation of signalfd.
Signalfd allows the application to receive siginfo_t information through an FD.
The FD is either provided by the application or created by the kernel depending.
This specifically doesn't pick up *true* synchronous signals. tgkill of the number
should theoretically go through this interface.
This very specifically skips our internal required signals for now.
This means it won't pick up SIGILL, SIGBUS, or SIG63.
This is enough to capture an application that just wants to poll for SIGCHLD.
Anything more complex has the same problems of the guest handling a siginfo_t.
gzip ships a PT_LOAD program section without a file size and only a memory size.
In the case of a zero file size PT_LOAD then return success immediately in this section loader.
This fixes Steam using gzip to package up crash logs
Don't print how many instructions are installed in the tables.
This isn't useful anymore
Not installing signal 32 and 33 are something we don't support right now. Stop complaining in that case.
Stop printing when a thread is starting up and shutting down. If you want to see this then gdb shows it well.
Don't print clone flags unless we are hitting a case where we are printing another log message.
Only the frontends need to deal with ELF files specifically.
The backend doesn't need to be aware of them at all.
Since the ELF handling is the frontend's responsibility, move all the code to the frontend.
In a newer version of the kernel there was a feature to disallow cpuid.
We can emulate this by saying it is always enabled and disallow the ability to disable it.
This was overwriting the cmd argument and then being checked in the switch statement
after the call.
Since it was overwritten, it wasn't falling down the correct path, returning a flock_32 instead of a flock64_32
Since the vector was being initialized with braces, this caused the
arrays to only ever have one element within it instead of the size of
the array.
While we're at it, we can also construct a vector in place with the
necessary size.
Ryan Houdek