3 files changed, 240 insertions, 0 deletions
diff --git a/extensions/otp-cache/Cargo.toml b/extensions/otp-cache/Cargo.toml
new file mode 100644
index 0000000..0d9a171
--- /dev/null
+++ b/extensions/otp-cache/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "nitrocli-otp-cache"
+version = "0.1.0"
+authors = ["Robin Krahl <robin.krahl@ireas.org>"]
+edition = "2018"
+
+[dependencies]
+anyhow = "1"
+serde = { version = "1", features = ["derive"] }
+structopt = { version = "0.3.17", default-features = false }
+toml = "0.5"
+xdg = "2"
diff --git a/extensions/otp-cache/src/ext.rs b/extensions/otp-cache/src/ext.rs
new file mode 100644
index 0000000..ccebd39
--- /dev/null
+++ b/extensions/otp-cache/src/ext.rs
@@ -0,0 +1,110 @@
+use std::ffi;
+use std::fmt;
+use std::process;
+use std::str;
+
+#[derive(Debug, structopt::StructOpt)]
+pub struct Args {
+  #[structopt(long, hidden(true))]
+  pub nitrocli: String,
+
+  #[structopt(long, hidden(true))]
+  pub verbosity: Option<String>,
+}
+
+#[derive(Debug)]
+pub struct Nitrocli {
+  cmd: process::Command,
+}
+
+#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub enum OtpAlgorithm {
+  Hotp,
+  Totp,
+}
+
+impl Args {
+  pub fn nitrocli(&self) -> Nitrocli {
+    // TODO: set verbosity args
+    Nitrocli::new(&self.nitrocli)
+  }
+}
+
+impl Nitrocli {
+  pub fn new(nitrocli: &str) -> Nitrocli {
+    Nitrocli {
+      cmd: process::Command::new(nitrocli),
+    }
+  }
+
+  pub fn arg(&mut self, arg: impl AsRef<ffi::OsStr>) -> &mut Nitrocli {
+    self.cmd.arg(arg);
+    self
+  }
+
+  pub fn args<I, S>(&mut self, args: I) -> &mut Nitrocli
+  where
+    I: IntoIterator<Item = S>,
+    S: AsRef<ffi::OsStr>,
+  {
+    self.cmd.args(args);
+    self
+  }
+
+  pub fn text(&mut self) -> anyhow::Result<String> {
+    let output = self.cmd.output()?;
+    if output.status.success() {
+      String::from_utf8(output.stdout).map_err(From::from)
+    } else {
+      Err(anyhow::anyhow!(
+        "nitrocli call failed: {}",
+        String::from_utf8_lossy(&output.stderr)
+      ))
+    }
+  }
+}
+
+impl fmt::Display for OtpAlgorithm {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    write!(
+      f,
+      "{}",
+      match self {
+        OtpAlgorithm::Hotp => "hotp",
+        OtpAlgorithm::Totp => "totp",
+      }
+    )
+  }
+}
+
+impl str::FromStr for OtpAlgorithm {
+  type Err = anyhow::Error;
+
+  fn from_str(s: &str) -> Result<OtpAlgorithm, Self::Err> {
+    match s {
+      "hotp" => Ok(OtpAlgorithm::Hotp),
+      "totp" => Ok(OtpAlgorithm::Totp),
+      _ => Err(anyhow::anyhow!("Unexpected OTP algorithm: {}", s)),
+    }
+  }
+}
+
+impl<'de> serde::Deserialize<'de> for OtpAlgorithm {
+  fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+  where
+    D: serde::Deserializer<'de>,
+  {
+    use serde::de::Error as _;
+
+    str::FromStr::from_str(&String::deserialize(deserializer)?).map_err(D::Error::custom)
+  }
+}
+
+impl serde::Serialize for OtpAlgorithm {
+  fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+  where
+    S: serde::Serializer,
+  {
+    self.to_string().serialize(serializer)
+  }
+}
diff --git a/extensions/otp-cache/src/main.rs b/extensions/otp-cache/src/main.rs
new file mode 100644
index 0000000..b5f0b90
--- /dev/null
+++ b/extensions/otp-cache/src/main.rs
@@ -0,0 +1,118 @@
+mod ext;
+
+use std::collections;
+use std::fs;
+use std::io;
+use std::path;
+
+type Cache = collections::BTreeMap<ext::OtpAlgorithm, Vec<Slot>>;
+
+#[derive(Debug, serde::Deserialize, serde::Serialize)]
+struct Slot {
+  name: String,
+  id: usize,
+}
+
+/// Access Nitrokey OTP slots by name
+#[derive(Debug, structopt::StructOpt)]
+#[structopt(bin_name = "nitrocli otp-cache")]
+struct Args {
+  /// Update the cached slot data
+  #[structopt(short, long)]
+  force_update: bool,
+
+  #[structopt(short, long, global = true, default_value = "totp")]
+  algorithm: ext::OtpAlgorithm,
+
+  #[structopt(subcommand)]
+  cmd: Command,
+
+  #[structopt(flatten)]
+  ext: ext::Args,
+}
+
+#[derive(Debug, structopt::StructOpt)]
+enum Command {
+  /// Generates a one-time passwords
+  Get {
+    /// The name of the OTP slot to generate a OTP from
+    name: String,
+  },
+  /// Lists the cached slots and their ID
+  List,
+}
+
+fn main() -> anyhow::Result<()> {
+  use structopt::StructOpt as _;
+
+  let args = Args::from_args();
+  let mut cache = get_cache(&args)?;
+  let slots = cache.remove(&args.algorithm).unwrap_or_default();
+
+  match &args.cmd {
+    Command::Get { name } => match slots.iter().find(|s| &s.name == name) {
+      Some(slot) => println!("{}", generate_otp(&args, slot.id)?),
+      None => anyhow::bail!("No OTP slot with the given name!"),
+    },
+    Command::List => {
+      println!("id\tslot");
+      for slot in slots {
+        println!("{}\t{}", slot.id, slot.name);
+      }
+    }
+  }
+
+  Ok(())
+}
+
+fn get_cache(args: &Args) -> anyhow::Result<Cache> {
+  // TODO: use model and serial number as cache file name
+  let cache_file =
+    xdg::BaseDirectories::with_prefix("nitrocli")?.place_cache_file("otp-cache/cache.toml")?;
+  if args.force_update || !cache_file.is_file() {
+    let cache = update_cache(args)?;
+    save_cache(&cache, &cache_file)?;
+    Ok(cache)
+  } else {
+    load_cache(&cache_file)
+  }
+}
+
+fn update_cache(args: &Args) -> anyhow::Result<Cache> {
+  let slots = args.ext.nitrocli().args(&["otp", "status"]).text()?;
+  let mut cache = Cache::new();
+  for line in slots.lines().skip(1) {
+    let parts: Vec<_> = line.splitn(3, "\t").collect();
+    if parts.len() == 3 {
+      let algorithm: ext::OtpAlgorithm = parts[0].parse()?;
+      let id: usize = parts[1].parse()?;
+      let name = parts[2].to_owned();
+      cache.entry(algorithm).or_default().push(Slot { name, id });
+    }
+  }
+  Ok(cache)
+}
+
+fn save_cache(cache: &Cache, path: &path::Path) -> anyhow::Result<()> {
+  use io::Write as _;
+
+  let mut f = fs::File::create(path)?;
+  f.write_all(&toml::to_vec(cache)?)?;
+  Ok(())
+}
+
+fn load_cache(path: &path::Path) -> anyhow::Result<Cache> {
+  let s = fs::read_to_string(path)?;
+  toml::from_str(&s).map_err(From::from)
+}
+
+fn generate_otp(args: &Args, slot: usize) -> anyhow::Result<String> {
+  args
+    .ext
+    .nitrocli()
+    .args(&["otp", "get"])
+    .arg(slot.to_string())
+    .arg("--algorithm")
+    .arg(args.algorithm.to_string())
+    .text()
+}