holey-bytes/hbxrt/src/main.rs

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Rust
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//! Holey Bytes Experimental Runtime
#![deny(unsafe_op_in_unsafe_fn)]
mod mem;
use {
hbvm::{mem::Address, Vm, VmRunOk},
nix::sys::mman::{mmap, MapFlags, ProtFlags},
std::{env::args, fs::File, num::NonZeroUsize, process::exit},
};
fn main() -> Result<(), Box<dyn std::error::Error>> {
eprintln!("== HB×RT (Holey Bytes Linux Runtime) v0.1 ==");
eprintln!("[W] Currently supporting only flat images");
let Some(image_path) = args().nth(1) else {
eprintln!("[E] Missing image path");
exit(1);
};
// Allocate stack
const STACK_SIZE: usize = 1024 * 1024 * 2;
let stack_ptr = unsafe {
mmap::<std::fs::File>(
None,
NonZeroUsize::new(STACK_SIZE).expect("Stack size should be > 0"),
ProtFlags::PROT_GROWSDOWN | ProtFlags::PROT_READ | ProtFlags::PROT_WRITE,
MapFlags::MAP_GROWSDOWN
| MapFlags::MAP_STACK
| MapFlags::MAP_ANON
| MapFlags::MAP_PRIVATE,
None,
0,
)
}?;
eprintln!("[I] Stack allocated at {stack_ptr:p}");
// Load program
eprintln!("[I] Loading image from \"{image_path}\"");
let file = File::open(image_path)?;
let ptr = unsafe {
mmap(
None,
NonZeroUsize::new(file.metadata()?.len() as usize).ok_or("File is empty")?,
ProtFlags::PROT_READ,
MapFlags::MAP_PRIVATE,
Some(&file),
0,
)?
};
eprintln!("[I] Image loaded at {ptr:p}");
let mut vm = unsafe { Vm::<_, 0>::new(mem::HostMemory, Address::new(ptr as u64)) };
vm.write_reg(254, stack_ptr as u64);
// Memory access fault handling
unsafe {
use nix::sys::signal;
extern "C" fn action(
_: std::ffi::c_int,
info: *mut nix::libc::siginfo_t,
_: *mut std::ffi::c_void,
) {
unsafe {
eprintln!("[E] Memory access fault at {:p}", (*info).si_addr());
exit(2);
}
}
signal::sigaction(
signal::Signal::SIGSEGV,
&nix::sys::signal::SigAction::new(
signal::SigHandler::SigAction(action),
signal::SaFlags::SA_NODEFER,
nix::sys::signalfd::SigSet::empty(),
),
)?;
}
// Execute program
let stat = loop {
match vm.run() {
Ok(VmRunOk::Breakpoint) => eprintln!(
"[I] Hit breakpoint\nIP: {}\n== Registers ==\n{:?}",
vm.pc, vm.registers
),
Ok(VmRunOk::Timer) => (),
Ok(VmRunOk::Ecall) => unsafe {
std::arch::asm!(
"syscall",
inlateout("rax") vm.registers[1].0,
in("rdi") vm.registers[2].0,
in("rsi") vm.registers[3].0,
in("rdx") vm.registers[4].0,
in("r10") vm.registers[5].0,
in("r8") vm.registers[6].0,
in("r9") vm.registers[7].0,
)
},
Ok(VmRunOk::End) => break Ok(()),
Err(e) => break Err(e),
}
};
eprintln!("\n== Registers ==\n{:?}", vm.registers);
if let Err(e) = stat {
eprintln!("\n[E] Runtime error: {e:?}");
exit(2);
}
Ok(())
}