opgpcard: Restrict values of id of set-identity

tools/src/bin/opgpcard/cli.rs

@@ -146,8 +146,8 @@ pub enum Command {
         #[clap(name = "card ident", short = 'c', long = "card")]
         ident: String,
 
-        #[clap(name = "identity")]
+        #[clap(name = "identity", value_enum)]
-        id: u8,
+        id: SetIdentityId,
     },
 }
 
@@ -358,3 +358,23 @@ impl From<TouchPolicy> for openpgp_card_sequoia::types::TouchPolicy {
         }
     }
 }
+
+#[derive(ValueEnum, Debug, Clone)]
+pub enum SetIdentityId {
+    #[clap(name = "0")]
+    Zero,
+    #[clap(name = "1")]
+    One,
+    #[clap(name = "2")]
+    Two,
+}
+
+impl From<SetIdentityId> for u8 {
+    fn from(id: SetIdentityId) -> Self {
+        match id {
+            SetIdentityId::Zero => 0,
+            SetIdentityId::One => 1,
+            SetIdentityId::Two => 2,
+        }
+    }
+}

tools/src/bin/opgpcard/main.rs

@@ -579,13 +579,12 @@ fn list_cards(format: OutputFormat, output_version: OutputVersion) -> Result<()>
     Ok(())
 }
 
-fn set_identity(ident: &str, id: u8) -> Result<(), Box<dyn std::error::Error>> {
+fn set_identity(ident: &str, id: cli::SetIdentityId) -> Result<(), Box<dyn std::error::Error>> {
     let backend = util::open_card(ident)?;
     let mut card = Card::new(backend);
     let mut open = card.transaction()?;
 
-    open.set_identity(id)?;
+    open.set_identity(u8::from(id))?;
-
     Ok(())
 }