Move the signal handler from ironfish-rust to ironfish-rust-nodejs

This removes the `libc` dependency from `ironfish-rust`, which is not
supported in generic WASM environments.

In addition to that:

* Removed the `triggerSegfault` function, which does not appear to be
  used anywhere.

* Replaced the call to `libc::exit()` with `std::process::abort()`. The
  two are not exactly equivalent, but the latter is better suited for
  the task. If we want equivalence, we can use `std::process::exit()`
  instead.

* Corrected the definition of `display_trace`: the argument to signal is
  `void (*sighandler_t)(int)`, but our `display_trace` was not accepting
  an int argument. This could lead to stack corruption on some platforms
  (on x86-64, the first argument is passed on a register, so no stack
  corruption can occur there, but other platforms may be affected).

* Changed the `STACK_TRACE` variable from being a `static mut` to a
  stack-local variable. This simplifies the implementation and also
  avoids potential issues with multi-threading.

* Protected the `backtrace_symbols_fd` symbol from being defined on
  platforms where it's not supported.

Author: andiflabs

Cargo.lock

@@ -31,11 +31,12 @@ base64 = "0.13.0"
 fish_hash = "0.3.0"
 ironfish = { path = "../ironfish-rust" }
 ironfish-frost = { version = "0.1.0" }
+ironfish-jubjub = { version = "0.1.0", features = ["multiply-many"] }
+libc = "0.2.150"
 napi = { version = "2.14.4", features = ["napi6"] }
 napi-derive = "2.14.6"
-ironfish-jubjub = { version = "0.1.0", features = ["multiply-many"] }
-rand = "0.8.5"
 num_cpus = "1.16.0"
+rand = "0.8.5"
 signal-hook = { version = "0.3.17", optional = true, default-features = false, features = ["iterator"] }
 
 [build-dependencies]

ironfish-rust-nodejs/Cargo.toml

@@ -2,19 +2,35 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
-use ironfish::signal_catcher::{init_signal_handler, trigger_segfault};
 use napi_derive::napi;
 
-/// # Safety
-/// This is unsafe, it calls libc functions
-#[napi(js_name = "initSignalHandler")]
-pub unsafe fn native_init_signal_handler() {
-    init_signal_handler()
+extern "C" {
+    #[cfg(all(unix, not(target_env = "musl"), not(target_os = "android")))]
+    fn backtrace_symbols_fd(buffer: *const *mut libc::c_void, size: libc::c_int, fd: libc::c_int);
 }
 
-/// # Safety
-/// This is unsafe, it intentionally crashes
-#[napi(js_name = "triggerSegfault")]
-pub unsafe fn native_trigger_segfault() {
-    trigger_segfault()
+fn display_trace(_signal: libc::c_int) {
+    #[cfg(all(unix, not(target_env = "musl"), not(target_os = "android")))]
+    unsafe {
+        const MAX_FRAMES: usize = 256;
+        let mut stack_trace = [std::ptr::null_mut(); MAX_FRAMES];
+        let depth = libc::backtrace(stack_trace.as_mut_ptr(), MAX_FRAMES as i32);
+        backtrace_symbols_fd(stack_trace.as_ptr(), depth, libc::STDERR_FILENO);
+    }
+
+    std::process::abort();
+}
+
+#[napi(js_name = "initSignalHandler")]
+pub fn init_signal_handler() {
+    #[cfg(unix)]
+    unsafe {
+        libc::signal(libc::SIGSEGV, display_trace as usize);
+        // Rust may throw one of these in place of a SIGSEGV when the platform does not have a
+        // native implementation for `abort()`, or sometimes when encountering internal errors,
+        // see: https://doc.rust-lang.org/std/intrinsics/fn.abort.html
+        libc::signal(libc::SIGBUS, display_trace as usize);
+        libc::signal(libc::SIGILL, display_trace as usize);
+        libc::signal(libc::SIGTRAP, display_trace as usize);
+    }
 }

ironfish-rust-nodejs/src/signal_catcher.rs

@@ -51,7 +51,6 @@ fish_hash = "0.3.0"
 ironfish_zkp = { version = "0.2.0", path = "../ironfish-zkp" }
 ironfish-jubjub = { version = "0.1.0", features = ["multiply-many"] }
 lazy_static = "1.4.0"
-libc = "0.2.126" # sub-dependency that needs a pinned version until a new release of cpufeatures: https://github.com/RustCrypto/utils/pull/789
 rand = "0.8.5"
 tiny-bip39 = "1.0"
 xxhash-rust = { version = "0.8.5", features = ["xxh3"] }

ironfish-rust/Cargo.toml

@@ -24,7 +24,6 @@ pub mod nacl;
 pub mod note;
 pub mod rolling_filter;
 pub mod serializing;
-pub mod signal_catcher;
 pub mod transaction;
 pub mod util;
 pub mod witness;