mirror of
https://github.com/fluencelabs/wasmer
synced 2025-04-03 16:31:02 +00:00
71 lines
2.0 KiB
Rust
71 lines
2.0 KiB
Rust
use libc::{c_void, siginfo_t};
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use nix::sys::signal::{sigaction, SaFlags, SigAction, SigHandler, SigSet, SIGBUS, SIGSEGV};
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/// `__register_frame` and `__deregister_frame` on macos take a single fde as an
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/// argument, so we need to parse the fde table here.
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///
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/// This is a pretty direct port of llvm's fde handling code:
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/// https://llvm.org/doxygen/RTDyldMemoryManager_8cpp_source.html.
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#[allow(clippy::cast_ptr_alignment)]
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#[cfg(target_os = "macos")]
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pub unsafe fn visit_fde(addr: *mut u8, size: usize, visitor: extern "C" fn(*mut u8)) {
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unsafe fn process_fde(entry: *mut u8, visitor: extern "C" fn(*mut u8)) -> *mut u8 {
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let mut p = entry;
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let length = (p as *const u32).read_unaligned();
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p = p.add(4);
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let offset = (p as *const u32).read_unaligned();
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if offset != 0 {
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visitor(entry);
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}
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p.add(length as usize)
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}
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let mut p = addr;
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let end = p.add(size);
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loop {
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if p >= end {
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break;
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}
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p = process_fde(p, visitor);
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}
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}
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#[cfg(not(target_os = "macos"))]
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pub unsafe fn visit_fde(addr: *mut u8, size: usize, visitor: extern "C" fn(*mut u8)) {
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visitor(addr);
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}
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extern "C" {
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#[cfg_attr(nightly, unwind(allowed))]
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fn throw_trap(ty: i32) -> !;
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}
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pub unsafe fn install_signal_handler() {
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let sa = SigAction::new(
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SigHandler::SigAction(signal_trap_handler),
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SaFlags::SA_ONSTACK | SaFlags::SA_SIGINFO,
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SigSet::empty(),
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);
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sigaction(SIGSEGV, &sa).unwrap();
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sigaction(SIGBUS, &sa).unwrap();
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}
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#[cfg_attr(nightly, unwind(allowed))]
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extern "C" fn signal_trap_handler(
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_signum: ::nix::libc::c_int,
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_siginfo: *mut siginfo_t,
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_ucontext: *mut c_void,
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) {
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unsafe {
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// Apparently, we can unwind from arbitary instructions, as long
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// as we don't need to catch the exception inside the function that
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// was interrupted.
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//
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// This works on macos, not sure about linux.
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throw_trap(2);
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}
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}
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