WIP: Logging electrum RPC panics on the connection

Cargo.toml

@@ -70,7 +70,7 @@ tempfile = "3.0"
 
 [profile.release]
 lto = true
-panic = 'abort'
+panic = 'unwind'
 codegen-units = 1
 
 [patch.crates-io.electrum-client]

src/electrum/server.rs

@@ -7,6 +7,7 @@ use std::net::IpAddr;
 use std::net::{Shutdown, SocketAddr, TcpListener, TcpStream};
 use std::os::unix::fs::FileTypeExt;
 use std::os::unix::net::{UnixListener, UnixStream};
+use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::path::Path;
 use std::sync::atomic::AtomicBool;
 use std::sync::mpsc::{Receiver, Sender};
@@ -903,7 +904,28 @@ impl RPC {
                             discovery,
                         );
                         senders.lock().unwrap().push(conn.chan.sender());
-                        conn.run();
+                        // unwind any panics inside the connection for logging
+                        //
+                        // Safety: we use AssertUnwindSafe because we don't have any
+                        //         interior mutability that could be left in an invalid state
+                        //         after a panic. We just log and exit the thread.
+                        let result = catch_unwind(AssertUnwindSafe(|| {
+                            conn.run();
+                        }));
+                        // panic occurred
+                        if let Err(err) = result {
+                            let msg = if let Some(s) = err.downcast_ref::<&str>() {
+                                *s
+                            } else if let Some(s) = err.downcast_ref::<String>() {
+                                s.as_str()
+                            } else {
+                                "(unknown panic payload)"
+                            };
+                            error!("[{}] connection panicked: {}", addr, msg);
+                            // Forward the panic for now just to keep the behavior similar to before
+                            // (Although panics were silently ignored before, so it's not the same)
+                            std::panic::panic_any(err);
+                        }
                         info!("[{}] disconnected peer", addr);
                         let _ = killer_clone.send(());
                         let _ = garbage_sender.send(std::thread::current().id());

start

@@ -9,6 +9,17 @@ NODENAME=$(hostname|cut -d . -f1)
 LOCATION=$(hostname|cut -d . -f2)
 USAGE="Usage: $0 (mainnet|testnet|signet|liquid|liquidtestnet) [popular-scripts]"
 
+# set default log verbosity if unset
+if [ -z "${ELECTRS_LOG_VERBOSITY+x}" ];then
+    ELECTRS_LOG_VERBOSITY="-vv"
+# validate log verbosity if set
+# Can be -v, -vv, -vvv, -vvvv or "" (set to empty string)
+elif [[ -n "${ELECTRS_LOG_VERBOSITY}" && ! "${ELECTRS_LOG_VERBOSITY}" =~ ^-v{1,4}$ ]];then
+    echo "[!] ELECTRS_LOG_VERBOSITY variable is set to invalid value '${ELECTRS_LOG_VERBOSITY}'." >&2
+	echo "[!] It must be one of: -v, -vv, -vvv, -vvvv or \"\". If unset it will default to -vv." >&2
+    exit 1
+fi
+
 # load rust if necessary
 if [ -e "${HOME}/.cargo/env" ];then
 	source "${HOME}/.cargo/env"
@@ -229,6 +240,6 @@ do
 		--address-search \
 		--utxos-limit "${UTXOS_LIMIT}" \
 		--electrum-txs-limit "${ELECTRUM_TXS_LIMIT}" \
-		-vv
+		"${ELECTRS_LOG_VERBOSITY}"
 	sleep 1
 done