fix(rpc): modify shutdown used in `stop()` (#8863)

* modify shutdown used in `stop()`

* use conditional compilation

* add note

* fix conditional compilation

Cargo.lock

@@ -692,6 +692,12 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
+
 [[package]]
 name = "chacha20"
 version = "0.9.1"
@@ -2650,6 +2656,18 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "nix"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
+dependencies = [
+ "bitflags 2.6.0",
+ "cfg-if 1.0.0",
+ "cfg_aliases",
+ "libc",
+]
+
 [[package]]
 name = "nom"
 version = "7.1.3"
@@ -6154,6 +6172,7 @@ dependencies = [
  "jsonrpc-core",
  "jsonrpc-derive",
  "jsonrpc-http-server",
+ "nix",
  "proptest",
  "prost",
  "rand 0.8.5",

zebra-rpc/Cargo.toml

@@ -87,6 +87,8 @@ tracing = "0.1.39"
 hex = { version = "0.4.3", features = ["serde"] }
 serde = { version = "1.0.204", features = ["serde_derive"] }
 
+# For the `stop` RPC method.
+nix = { version = "0.29.0", features = ["signal"] }
 
 zcash_primitives = { workspace = true, features = ["transparent-inputs"] }
 

zebra-rpc/src/methods.rs

@@ -302,17 +302,18 @@ pub trait Rpc {
         address_strings: AddressStrings,
     ) -> BoxFuture<Result<Vec<GetAddressUtxos>>>;
 
-    #[rpc(name = "stop")]
     /// Stop the running zebrad process.
     ///
     /// # Notes
     ///
-    /// Only works if the network of the running zebrad process is `Regtest`.
+    /// - Works for non windows targets only.
+    /// - Works only if the network of the running zebrad process is `Regtest`.
     ///
     /// zcashd reference: [`stop`](https://zcash.github.io/rpc/stop.html)
     /// method: post
     /// tags: control
-    fn stop(&self) -> Result<()>;
+    #[rpc(name = "stop")]
+    fn stop(&self) -> Result<String>;
 }
 
 /// RPC method implementations.
@@ -1357,10 +1358,17 @@ where
         .boxed()
     }
 
-    fn stop(&self) -> Result<()> {
+    fn stop(&self) -> Result<String> {
+        #[cfg(not(target_os = "windows"))]
         if self.network.is_regtest() {
-            // TODO: Use graceful termination in `stop` RPC (#8850)
-            std::process::exit(0);
+            match nix::sys::signal::raise(nix::sys::signal::SIGINT) {
+                Ok(_) => Ok("Zebra server stopping".to_string()),
+                Err(error) => Err(Error {
+                    code: ErrorCode::InternalError,
+                    message: format!("Failed to shut down: {}", error),
+                    data: None,
+                }),
+            }
         } else {
             Err(Error {
                 code: ErrorCode::MethodNotFound,
@@ -1368,6 +1376,12 @@ where
                 data: None,
             })
         }
+        #[cfg(target_os = "windows")]
+        Err(Error {
+            code: ErrorCode::MethodNotFound,
+            message: "stop is not available in windows targets".to_string(),
+            data: None,
+        })
     }
 }