refactor: update reading arguments

Author: aghiles-ait

cvmassistants/quote-generator/src/error.rs

@@ -4,8 +4,8 @@ use std::array::TryFromSliceError;
 
 #[derive(Error, Debug)]
 pub enum QuoteGeneratorError {
-    #[error("Invalid usage: expected exactly 1 argument (report data)")]
-    InvalidUsage,
+    #[error("Invalid usage: expected exactly 1 argument (report data), received {actual}")]
+    InvalidUsage { actual: usize },
 
     #[error("Report data must be at most {max} bytes, got {actual} bytes")]
     ReportDataTooLarge { max: usize, actual: usize },

cvmassistants/quote-generator/src/main.rs

@@ -132,8 +132,7 @@ fn main() -> Result<(), QuoteGeneratorError> {
 
     let args: Vec<String> = env::args().collect();
     if args.len() != 2 {
-        error!("Usage: {} <{}-byte-report-data>", args[0], REPORT_DATA_SIZE);
-        process::exit(1);
+        return Err(QuoteGeneratorError::InvalidUsage { actual: args.len() });
     }
 
     let input = &args[1];