allow reading message from file

coordinator/src/args.rs

@@ -13,6 +13,11 @@ pub struct Args {
     #[arg(short = 'P', long, default_value = "public-key-package.json")]
     pub public_key_package: String,
 
+    /// The message to sign. Can be a file with the raw message, or "-". If "-"
+    /// is specified, then it will be read from standard input as a hex string.
+    #[arg(short = 'm', long, default_value = "-")]
+    pub message: String,
+
     /// Where to write the generated raw bytes signature. If "-", the
     /// human-readable hex-string is printed to stdout.
     #[arg(short = 's', long, default_value = "-")]

coordinator/src/cli.rs

@@ -32,7 +32,13 @@ pub async fn cli(
         "=== STEP 2: CHOOSE MESSAGE AND GENERATE COMMITMENT PACKAGE ===\n"
     )?;
 
-    let signing_package = step_2(reader, logger, participants_config.commitments.clone()).await?;
+    let signing_package = step_2(
+        args,
+        reader,
+        logger,
+        participants_config.commitments.clone(),
+    )
+    .await?;
 
     #[cfg(feature = "redpallas")]
     let randomizer = request_randomizer(reader, logger)?;

coordinator/src/step_2.rs

@@ -7,38 +7,47 @@ use frost::{round1::SigningCommitments, Identifier, SigningPackage};
 
 use std::{
     collections::BTreeMap,
+    fs,
     io::{BufRead, Write},
 };
 
+use crate::args::Args;
+
 #[derive(Debug, PartialEq, Clone)]
 pub struct CommitmentsConfig {
     pub message: Vec<u8>,
     pub signer_commitments: BTreeMap<Identifier, SigningCommitments>,
 }
 
 pub async fn step_2(
+    args: &Args,
     input: &mut impl BufRead,
     logger: &mut dyn Write,
     commitments: BTreeMap<Identifier, SigningCommitments>,
 ) -> Result<SigningPackage, Box<dyn std::error::Error>> {
-    let signing_package = request_message(input, logger, commitments)?;
+    let signing_package = request_message(args, input, logger, commitments)?;
     print_signing_package(logger, &signing_package);
     Ok(signing_package)
 }
 
 // Input required:
 // 1. message
 fn request_message(
+    args: &Args,
     input: &mut impl BufRead,
     logger: &mut dyn Write,
     commitments: BTreeMap<Identifier, SigningCommitments>,
 ) -> Result<SigningPackage, Box<dyn std::error::Error>> {
-    writeln!(logger, "The message to be signed (hex encoded)")?;
+    let message = if args.message == "-" {
+        writeln!(logger, "The message to be signed (hex encoded)")?;
 
-    let mut msg = String::new();
-    input.read_line(&mut msg)?;
+        let mut msg = String::new();
+        input.read_line(&mut msg)?;
 
-    let message = hex::decode(msg.trim())?;
+        hex::decode(msg.trim())?
+    } else {
+        fs::read(&args.message)?
+    };
 
     let signing_package = SigningPackage::new(commitments, &message);