node: Some small UX fixes

Fixes an error which said "invalid argument" the first time the node was
started.

radicle-cli/src/commands/node/control.rs

@@ -81,14 +81,14 @@ pub fn logs(lines: usize, follow: Option<time::Duration>, profile: &Profile) ->
     let logs = profile.home.node().join("node.log");
 
     let mut file = BufReader::new(File::open(logs)?);
-    file.seek(SeekFrom::End(-1))?;
+    file.seek(SeekFrom::End(0))?;
 
     let mut tail = Vec::new();
     let mut nlines = 0;
 
-    for i in (0..=file.stream_position()?).rev() {
+    for i in (1..=file.stream_position()?).rev() {
         let mut buf = [0; 1];
-        file.seek(SeekFrom::Start(i))?;
+        file.seek(SeekFrom::Start(i - 1))?;
         file.read_exact(&mut buf)?;
 
         if buf[0] == b'\n' {

radicle-crypto/src/ssh/keystore.rs

@@ -153,6 +153,8 @@ pub enum MemorySignerError {
     Keystore(#[from] Error),
     #[error("key not found in '{0}'")]
     NotFound(PathBuf),
+    #[error("invalid passphrase")]
+    InvalidPassphrase,
 }
 
 /// An in-memory signer that keeps its secret key internally
@@ -217,7 +219,14 @@ impl MemorySigner {
             .public_key()?
             .ok_or_else(|| MemorySignerError::NotFound(keystore.path().to_path_buf()))?;
         let secret = keystore
-            .secret_key(passphrase)?
+            .secret_key(passphrase)
+            .map_err(|e| {
+                if e.is_crypto_err() {
+                    MemorySignerError::InvalidPassphrase
+                } else {
+                    e.into()
+                }
+            })?
             .ok_or_else(|| MemorySignerError::NotFound(keystore.path().to_path_buf()))?;
 
         Ok(Self { public, secret })

radicle-node/src/main.rs

@@ -1,7 +1,7 @@
 use std::io;
 use std::{env, fs, net, process};
 
-use anyhow::anyhow;
+use anyhow::{anyhow, Context};
 use crossbeam_channel as chan;
 use cyphernet::addr::PeerAddr;
 use localtime::LocalDuration;
@@ -142,7 +142,7 @@ fn execute() -> anyhow::Result<()> {
 
     let passphrase = profile::env::passphrase();
     let keystore = Keystore::new(&home.keys());
-    let signer = MemorySigner::load(&keystore, passphrase)?;
+    let signer = MemorySigner::load(&keystore, passphrase).context("couldn't load secret key")?;
 
     log::info!(target: "node", "Node ID is {}", signer.public_key());