2 use crate::error::Error;
4 use crate::sys_common::backtrace::Frame;
5 use crate::sys::sgx::abi::mem::image_base;
9 pub struct BacktraceContext;
13 frames: &'a mut [Frame],
17 struct UnwindError(uw::_Unwind_Reason_Code);
19 impl Error for UnwindError {
20 fn description(&self) -> &'static str {
21 "unexpected return value while unwinding"
25 impl fmt::Display for UnwindError {
26 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
27 write!(f, "{}: {:?}", self.description(), self.0)
31 #[inline(never)] // this function call can be skipped it when tracing.
32 pub fn unwind_backtrace(frames: &mut [Frame]) -> io::Result<(usize, BacktraceContext)> {
33 let mut cx = Context { idx: 0, frames };
34 let result_unwind = unsafe {
35 uw::_Unwind_Backtrace(trace_fn, &mut cx as *mut Context<'_> as *mut libc::c_void)
37 // See libunwind:src/unwind/Backtrace.c for the return values.
38 // No, there is no doc.
39 let res = match result_unwind {
40 // These return codes seem to be benign and need to be ignored for backtraces
41 // to show up properly on all tested platforms.
42 uw::_URC_END_OF_STACK | uw::_URC_FATAL_PHASE1_ERROR | uw::_URC_FAILURE => {
43 Ok((cx.idx, BacktraceContext))
45 _ => Err(io::Error::new(
47 UnwindError(result_unwind),
53 extern "C" fn trace_fn(
54 ctx: *mut uw::_Unwind_Context,
55 arg: *mut libc::c_void,
56 ) -> uw::_Unwind_Reason_Code {
57 let cx = unsafe { &mut *(arg as *mut Context<'_>) };
58 if cx.idx >= cx.frames.len() {
59 return uw::_URC_NORMAL_STOP;
62 let mut ip_before_insn = 0;
63 let mut ip = unsafe { uw::_Unwind_GetIPInfo(ctx, &mut ip_before_insn) as *mut libc::c_void };
64 if !ip.is_null() && ip_before_insn == 0 {
65 // this is a non-signaling frame, so `ip` refers to the address
66 // after the calling instruction. account for that.
67 ip = (ip as usize - 1) as *mut _;
70 let symaddr = unsafe { uw::_Unwind_FindEnclosingFunction(ip) };
71 cx.frames[cx.idx] = Frame {
72 symbol_addr: symaddr as *mut u8,
73 exact_position: ip as *mut u8,
81 // To reduce TCB size in Sgx enclave, we do not want to implement resolve_symname functionality.
82 // Rather, we print the offset of the address here, which could be later mapped to correct function.
83 pub fn resolve_symname<F>(frame: Frame,
85 _: &BacktraceContext) -> io::Result<()>
86 where F: FnOnce(Option<&str>) -> io::Result<()>
88 callback(Some(&format!("0x{:x}",
89 (frame.symbol_addr.wrapping_offset_from(image_base() as _)))))
92 pub fn foreach_symbol_fileline<F>(_: Frame,
94 _: &BacktraceContext) -> io::Result<bool>
95 where F: FnMut(&[u8], u32) -> io::Result<()>