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wasmer/lib/runtime-core/src/fault.rs
losfair f32b22d571 Bkpt* -> Breakpoint*
2019-07-04 01:45:06 +08:00

465 lines
16 KiB
Rust
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mod raw {
use std::ffi::c_void;
extern "C" {
pub fn run_on_alternative_stack(stack_end: *mut u64, stack_begin: *mut u64) -> u64;
pub fn setjmp(env: *mut c_void) -> i32;
pub fn longjmp(env: *mut c_void, val: i32) -> !;
}
}
use crate::codegen::{BreakpointInfo, BreakpointMap};
use crate::state::x64::{build_instance_image, read_stack, X64Register, GPR, XMM};
use crate::vm;
use libc::{mmap, mprotect, siginfo_t, MAP_ANON, MAP_PRIVATE, PROT_NONE, PROT_READ, PROT_WRITE};
use nix::sys::signal::{
sigaction, SaFlags, SigAction, SigHandler, SigSet, Signal, SIGBUS, SIGFPE, SIGILL, SIGINT,
SIGSEGV, SIGTRAP,
};
use std::any::Any;
use std::cell::UnsafeCell;
use std::ffi::c_void;
use std::process;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Once;
pub(crate) unsafe fn run_on_alternative_stack(stack_end: *mut u64, stack_begin: *mut u64) -> u64 {
raw::run_on_alternative_stack(stack_end, stack_begin)
}
const TRAP_STACK_SIZE: usize = 1048576; // 1MB
const SETJMP_BUFFER_LEN: usize = 27;
type SetJmpBuffer = [i32; SETJMP_BUFFER_LEN];
struct UnwindInfo {
jmpbuf: SetJmpBuffer, // in
breakpoints: Option<BreakpointMap>,
payload: Option<Box<Any>>, // out
}
thread_local! {
static UNWIND: UnsafeCell<Option<UnwindInfo>> = UnsafeCell::new(None);
}
struct InterruptSignalMem(*mut u8);
unsafe impl Send for InterruptSignalMem {}
unsafe impl Sync for InterruptSignalMem {}
const INTERRUPT_SIGNAL_MEM_SIZE: usize = 4096;
lazy_static! {
static ref INTERRUPT_SIGNAL_MEM: InterruptSignalMem = {
let ptr = unsafe {
mmap(
::std::ptr::null_mut(),
INTERRUPT_SIGNAL_MEM_SIZE,
PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANON,
-1,
0,
)
};
if ptr as isize == -1 {
panic!("cannot allocate code memory");
}
InterruptSignalMem(ptr as _)
};
}
static INTERRUPT_SIGNAL_DELIVERED: AtomicBool = AtomicBool::new(false);
pub unsafe fn get_wasm_interrupt_signal_mem() -> *mut u8 {
INTERRUPT_SIGNAL_MEM.0
}
pub unsafe fn set_wasm_interrupt() {
let mem: *mut u8 = INTERRUPT_SIGNAL_MEM.0;
if mprotect(mem as _, INTERRUPT_SIGNAL_MEM_SIZE, PROT_NONE) < 0 {
panic!("cannot set PROT_NONE on signal mem");
}
}
pub unsafe fn clear_wasm_interrupt() {
let mem: *mut u8 = INTERRUPT_SIGNAL_MEM.0;
if mprotect(mem as _, INTERRUPT_SIGNAL_MEM_SIZE, PROT_READ | PROT_WRITE) < 0 {
panic!("cannot set PROT_READ | PROT_WRITE on signal mem");
}
}
pub unsafe fn catch_unsafe_unwind<R, F: FnOnce() -> R>(
f: F,
breakpoints: Option<BreakpointMap>,
) -> Result<R, Box<Any>> {
let unwind = UNWIND.with(|x| x.get());
let old = (*unwind).take();
*unwind = Some(UnwindInfo {
jmpbuf: [0; SETJMP_BUFFER_LEN],
breakpoints: breakpoints,
payload: None,
});
if raw::setjmp(&mut (*unwind).as_mut().unwrap().jmpbuf as *mut SetJmpBuffer as *mut _) != 0 {
// error
let ret = (*unwind).as_mut().unwrap().payload.take().unwrap();
*unwind = old;
Err(ret)
} else {
let ret = f();
// implicit control flow to the error case...
*unwind = old;
Ok(ret)
}
}
pub unsafe fn begin_unsafe_unwind(e: Box<Any>) -> ! {
let unwind = UNWIND.with(|x| x.get());
let inner = (*unwind)
.as_mut()
.expect("not within a catch_unsafe_unwind scope");
inner.payload = Some(e);
raw::longjmp(&mut inner.jmpbuf as *mut SetJmpBuffer as *mut _, 0xffff);
}
unsafe fn with_breakpoint_map<R, F: FnOnce(Option<&BreakpointMap>) -> R>(f: F) -> R {
let unwind = UNWIND.with(|x| x.get());
let inner = (*unwind)
.as_mut()
.expect("not within a catch_unsafe_unwind scope");
f(inner.breakpoints.as_ref())
}
pub fn allocate_and_run<R, F: FnOnce() -> R>(size: usize, f: F) -> R {
struct Context<F: FnOnce() -> R, R> {
f: Option<F>,
ret: Option<R>,
}
extern "C" fn invoke<F: FnOnce() -> R, R>(ctx: &mut Context<F, R>) {
let f = ctx.f.take().unwrap();
ctx.ret = Some(f());
}
unsafe {
let mut ctx = Context {
f: Some(f),
ret: None,
};
assert!(size % 16 == 0);
assert!(size >= 4096);
let mut stack: Vec<u64> = vec![0; size / 8];
let end_offset = stack.len();
stack[end_offset - 4] = invoke::<F, R> as usize as u64;
// NOTE: Keep this consistent with `image-loading-*.s`.
stack[end_offset - 4 - 10] = &mut ctx as *mut Context<F, R> as usize as u64; // rdi
const NUM_SAVED_REGISTERS: usize = 23;
let stack_begin = stack
.as_mut_ptr()
.offset((end_offset - 4 - NUM_SAVED_REGISTERS) as isize);
let stack_end = stack.as_mut_ptr().offset(end_offset as isize);
raw::run_on_alternative_stack(stack_end, stack_begin);
ctx.ret.take().unwrap()
}
}
extern "C" fn signal_trap_handler(
signum: ::nix::libc::c_int,
siginfo: *mut siginfo_t,
ucontext: *mut c_void,
) {
unsafe {
let fault = get_fault_info(siginfo as _, ucontext);
let mut unwind_result: Box<dyn Any> = Box::new(());
let should_unwind = allocate_and_run(TRAP_STACK_SIZE, || {
let mut is_suspend_signal = false;
match Signal::from_c_int(signum) {
Ok(SIGTRAP) => {
// breakpoint
let out: Option<Result<(), Box<dyn Any>>> = with_breakpoint_map(|bkpt_map| {
bkpt_map.and_then(|x| x.get(&(fault.ip as usize))).map(|x| {
x(BreakpointInfo {
fault: Some(&fault),
})
})
});
match out {
Some(Ok(())) => {
return false;
}
Some(Err(e)) => {
unwind_result = e;
return true;
}
None => {}
}
}
Ok(SIGSEGV) | Ok(SIGBUS) => {
if fault.faulting_addr as usize == get_wasm_interrupt_signal_mem() as usize {
is_suspend_signal = true;
clear_wasm_interrupt();
INTERRUPT_SIGNAL_DELIVERED.store(false, Ordering::SeqCst);
}
}
_ => {}
}
// TODO: make this safer
let ctx = &mut *(fault.known_registers[X64Register::GPR(GPR::R15).to_index().0].unwrap()
as *mut vm::Ctx);
let rsp = fault.known_registers[X64Register::GPR(GPR::RSP).to_index().0].unwrap();
let msm = (*ctx.module)
.runnable_module
.get_module_state_map()
.unwrap();
let code_base = (*ctx.module).runnable_module.get_code().unwrap().as_ptr() as usize;
let es_image = read_stack(
&msm,
code_base,
rsp as usize as *const u64,
fault.known_registers,
Some(fault.ip as usize as u64),
);
if is_suspend_signal {
let image = build_instance_image(ctx, es_image);
unwind_result = Box::new(image);
} else {
use colored::*;
if es_image.frames.len() > 0 {
eprintln!(
"\n{}",
"Wasmer encountered an error while running your WebAssembly program."
.bold()
.red()
);
es_image.print_backtrace_if_needed();
}
// Just let the error propagate otherrwise
}
true
});
if should_unwind {
begin_unsafe_unwind(unwind_result);
}
}
}
extern "C" fn sigint_handler(
_signum: ::nix::libc::c_int,
_siginfo: *mut siginfo_t,
_ucontext: *mut c_void,
) {
if INTERRUPT_SIGNAL_DELIVERED.swap(true, Ordering::SeqCst) {
eprintln!("Got another SIGINT before trap is triggered on WebAssembly side, aborting");
process::abort();
}
unsafe {
set_wasm_interrupt();
}
}
pub fn ensure_sighandler() {
INSTALL_SIGHANDLER.call_once(|| unsafe {
install_sighandler();
});
}
static INSTALL_SIGHANDLER: Once = Once::new();
unsafe fn install_sighandler() {
let sa_trap = SigAction::new(
SigHandler::SigAction(signal_trap_handler),
SaFlags::SA_ONSTACK,
SigSet::empty(),
);
sigaction(SIGFPE, &sa_trap).unwrap();
sigaction(SIGILL, &sa_trap).unwrap();
sigaction(SIGSEGV, &sa_trap).unwrap();
sigaction(SIGBUS, &sa_trap).unwrap();
sigaction(SIGTRAP, &sa_trap).unwrap();
let sa_interrupt = SigAction::new(
SigHandler::SigAction(sigint_handler),
SaFlags::SA_ONSTACK,
SigSet::empty(),
);
sigaction(SIGINT, &sa_interrupt).unwrap();
}
pub struct FaultInfo {
pub faulting_addr: *const c_void,
pub ip: *const c_void,
pub known_registers: [Option<u64>; 24],
}
#[cfg(all(target_os = "linux", target_arch = "x86_64"))]
pub unsafe fn get_fault_info(siginfo: *const c_void, ucontext: *const c_void) -> FaultInfo {
use libc::{
_libc_xmmreg, ucontext_t, REG_R10, REG_R11, REG_R12, REG_R13, REG_R14, REG_R15, REG_R8,
REG_R9, REG_RAX, REG_RBP, REG_RBX, REG_RCX, REG_RDI, REG_RDX, REG_RIP, REG_RSI, REG_RSP,
};
fn read_xmm(reg: &_libc_xmmreg) -> u64 {
(reg.element[0] as u64) | ((reg.element[1] as u64) << 32)
}
#[allow(dead_code)]
#[repr(C)]
struct siginfo_t {
si_signo: i32,
si_errno: i32,
si_code: i32,
si_addr: u64,
// ...
}
let siginfo = siginfo as *const siginfo_t;
let si_addr = (*siginfo).si_addr;
let ucontext = ucontext as *const ucontext_t;
let gregs = &(*ucontext).uc_mcontext.gregs;
let fpregs = &*(*ucontext).uc_mcontext.fpregs;
let mut known_registers: [Option<u64>; 24] = [None; 24];
known_registers[X64Register::GPR(GPR::R15).to_index().0] = Some(gregs[REG_R15 as usize] as _);
known_registers[X64Register::GPR(GPR::R14).to_index().0] = Some(gregs[REG_R14 as usize] as _);
known_registers[X64Register::GPR(GPR::R13).to_index().0] = Some(gregs[REG_R13 as usize] as _);
known_registers[X64Register::GPR(GPR::R12).to_index().0] = Some(gregs[REG_R12 as usize] as _);
known_registers[X64Register::GPR(GPR::R11).to_index().0] = Some(gregs[REG_R11 as usize] as _);
known_registers[X64Register::GPR(GPR::R10).to_index().0] = Some(gregs[REG_R10 as usize] as _);
known_registers[X64Register::GPR(GPR::R9).to_index().0] = Some(gregs[REG_R9 as usize] as _);
known_registers[X64Register::GPR(GPR::R8).to_index().0] = Some(gregs[REG_R8 as usize] as _);
known_registers[X64Register::GPR(GPR::RSI).to_index().0] = Some(gregs[REG_RSI as usize] as _);
known_registers[X64Register::GPR(GPR::RDI).to_index().0] = Some(gregs[REG_RDI as usize] as _);
known_registers[X64Register::GPR(GPR::RDX).to_index().0] = Some(gregs[REG_RDX as usize] as _);
known_registers[X64Register::GPR(GPR::RCX).to_index().0] = Some(gregs[REG_RCX as usize] as _);
known_registers[X64Register::GPR(GPR::RBX).to_index().0] = Some(gregs[REG_RBX as usize] as _);
known_registers[X64Register::GPR(GPR::RAX).to_index().0] = Some(gregs[REG_RAX as usize] as _);
known_registers[X64Register::GPR(GPR::RBP).to_index().0] = Some(gregs[REG_RBP as usize] as _);
known_registers[X64Register::GPR(GPR::RSP).to_index().0] = Some(gregs[REG_RSP as usize] as _);
known_registers[X64Register::XMM(XMM::XMM0).to_index().0] = Some(read_xmm(&fpregs._xmm[0]));
known_registers[X64Register::XMM(XMM::XMM1).to_index().0] = Some(read_xmm(&fpregs._xmm[1]));
known_registers[X64Register::XMM(XMM::XMM2).to_index().0] = Some(read_xmm(&fpregs._xmm[2]));
known_registers[X64Register::XMM(XMM::XMM3).to_index().0] = Some(read_xmm(&fpregs._xmm[3]));
known_registers[X64Register::XMM(XMM::XMM4).to_index().0] = Some(read_xmm(&fpregs._xmm[4]));
known_registers[X64Register::XMM(XMM::XMM5).to_index().0] = Some(read_xmm(&fpregs._xmm[5]));
known_registers[X64Register::XMM(XMM::XMM6).to_index().0] = Some(read_xmm(&fpregs._xmm[6]));
known_registers[X64Register::XMM(XMM::XMM7).to_index().0] = Some(read_xmm(&fpregs._xmm[7]));
FaultInfo {
faulting_addr: si_addr as usize as _,
ip: gregs[REG_RIP as usize] as _,
known_registers,
}
}
#[cfg(all(target_os = "macos", target_arch = "x86_64"))]
pub unsafe fn get_fault_info(siginfo: *const c_void, ucontext: *const c_void) -> FaultInfo {
#[allow(dead_code)]
#[repr(C)]
struct ucontext_t {
uc_onstack: u32,
uc_sigmask: u32,
uc_stack: libc::stack_t,
uc_link: *const ucontext_t,
uc_mcsize: u64,
uc_mcontext: *const mcontext_t,
}
#[repr(C)]
struct exception_state {
trapno: u16,
cpu: u16,
err: u32,
faultvaddr: u64,
}
#[repr(C)]
struct regs {
rax: u64,
rbx: u64,
rcx: u64,
rdx: u64,
rdi: u64,
rsi: u64,
rbp: u64,
rsp: u64,
r8: u64,
r9: u64,
r10: u64,
r11: u64,
r12: u64,
r13: u64,
r14: u64,
r15: u64,
rip: u64,
rflags: u64,
cs: u64,
fs: u64,
gs: u64,
}
#[repr(C)]
struct fpstate {
_unused: [u8; 168],
xmm: [[u64; 2]; 8],
}
#[allow(dead_code)]
#[repr(C)]
struct mcontext_t {
es: exception_state,
ss: regs,
fs: fpstate,
}
let siginfo = siginfo as *const siginfo_t;
let si_addr = (*siginfo).si_addr;
let ucontext = ucontext as *const ucontext_t;
let ss = &(*(*ucontext).uc_mcontext).ss;
let fs = &(*(*ucontext).uc_mcontext).fs;
let mut known_registers: [Option<u64>; 24] = [None; 24];
known_registers[X64Register::GPR(GPR::R15).to_index().0] = Some(ss.r15);
known_registers[X64Register::GPR(GPR::R14).to_index().0] = Some(ss.r14);
known_registers[X64Register::GPR(GPR::R13).to_index().0] = Some(ss.r13);
known_registers[X64Register::GPR(GPR::R12).to_index().0] = Some(ss.r12);
known_registers[X64Register::GPR(GPR::R11).to_index().0] = Some(ss.r11);
known_registers[X64Register::GPR(GPR::R10).to_index().0] = Some(ss.r10);
known_registers[X64Register::GPR(GPR::R9).to_index().0] = Some(ss.r9);
known_registers[X64Register::GPR(GPR::R8).to_index().0] = Some(ss.r8);
known_registers[X64Register::GPR(GPR::RSI).to_index().0] = Some(ss.rsi);
known_registers[X64Register::GPR(GPR::RDI).to_index().0] = Some(ss.rdi);
known_registers[X64Register::GPR(GPR::RDX).to_index().0] = Some(ss.rdx);
known_registers[X64Register::GPR(GPR::RCX).to_index().0] = Some(ss.rcx);
known_registers[X64Register::GPR(GPR::RBX).to_index().0] = Some(ss.rbx);
known_registers[X64Register::GPR(GPR::RAX).to_index().0] = Some(ss.rax);
known_registers[X64Register::GPR(GPR::RBP).to_index().0] = Some(ss.rbp);
known_registers[X64Register::GPR(GPR::RSP).to_index().0] = Some(ss.rsp);
known_registers[X64Register::XMM(XMM::XMM0).to_index().0] = Some(fs.xmm[0][0]);
known_registers[X64Register::XMM(XMM::XMM1).to_index().0] = Some(fs.xmm[1][0]);
known_registers[X64Register::XMM(XMM::XMM2).to_index().0] = Some(fs.xmm[2][0]);
known_registers[X64Register::XMM(XMM::XMM3).to_index().0] = Some(fs.xmm[3][0]);
known_registers[X64Register::XMM(XMM::XMM4).to_index().0] = Some(fs.xmm[4][0]);
known_registers[X64Register::XMM(XMM::XMM5).to_index().0] = Some(fs.xmm[5][0]);
known_registers[X64Register::XMM(XMM::XMM6).to_index().0] = Some(fs.xmm[6][0]);
known_registers[X64Register::XMM(XMM::XMM7).to_index().0] = Some(fs.xmm[7][0]);
FaultInfo {
faulting_addr: si_addr,
ip: ss.rip as _,
known_registers,
}
}
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