Reading/writing unencrypted db properties and starting work on getting the master key

Cargo.toml

@@ -13,6 +13,7 @@ log = "0.4.6"
 pretty_env_logger = "0.3.0"
 rand = "0.6.5"
 dirs = "2.0.0"
+rust-crypto = "0.2.36"
 
 [dependencies.rusqlite]
 version = "0.18.0"

src/db.rs

@@ -1,4 +1,5 @@
 use rusqlite::Connection;
+use std::error::Error;
 use std::path::PathBuf;
 
 static DB_INIT_QUERY: &'static str = include_str!("init.sql");
@@ -7,6 +8,12 @@ pub struct DbHandle {
     conn: Connection,
 }
 
+#[derive(Debug, Clone)]
+struct DbProperty {
+    name: String,
+    value: Option<String>,
+}
+
 impl DbHandle {
     pub fn new(db_path: &Option<String>) -> DbHandle {
         let path: PathBuf = db_path
@@ -19,4 +26,31 @@ impl DbHandle {
         tx.commit();
         DbHandle { conn: conn }
     }
+
+    pub fn get_db_property(&self, name: &str) -> Result<Option<String>, Box<dyn Error>> {
+        let mut stmt = self
+            .conn
+            .prepare("SELECT name, value FROM props WHERE name=$1")
+            .unwrap();
+        let mut props = stmt.query_map(&[&name], |row| {
+            Ok(DbProperty {
+                name: row.get(0)?,
+                value: row.get(1)?,
+            })
+        })?;
+
+        match props.next() {
+            Some(prop) => Ok(Some(prop.unwrap().value.unwrap())),
+            None => Ok(None),
+        }
+    }
+
+    pub fn set_db_property(&self, name: &str, value: &str) {
+        self.conn
+            .execute(
+                "INSERT OR REPLACE INTO props (name, value) VALUES ($1, $2)",
+                &[&name, &value],
+            )
+            .unwrap();
+    }
 }

src/main.rs

@@ -1,5 +1,8 @@
 use docopt::Docopt;
 use log::debug;
+use rand::rngs::OsRng;
+use rand::seq::IteratorRandom;
+use rand::seq::SliceRandom;
 use serde::Deserialize;
 use std::error::Error;
 
@@ -32,6 +35,31 @@ struct Args {
     arg_spec: Option<String>,
 }
 
+fn get_master_key(db_conn: &mut db::DbHandle) -> [u8; 32] {
+    let known_string = db_conn
+        .get_db_property("known_string")
+        .unwrap_or_else(|error| {
+            panic!("There was a problem reading from the db: {:?}", error);
+        })
+        .unwrap_or_else(|| {
+            println!("No master password set yet, create new one:");
+            let mut random = OsRng::new().unwrap();
+            let new_known: String = {
+                let mut new_chars: Vec<char> = "abcdefghijklmnopqrstuvwxyz"
+                    .chars()
+                    .choose_multiple(&mut random, 64);
+                new_chars.shuffle(&mut random);
+                new_chars.into_iter().collect()
+            };
+            db_conn.set_db_property("known_string", &new_known);
+            new_known
+        });
+
+    let master_key: [u8; 32] = [0; 32];
+
+    master_key
+}
+
 fn main() -> Result<(), Box<dyn Error>> {
     pretty_env_logger::init();
     let args: Args = Docopt::new(USAGE)
@@ -46,5 +74,7 @@ fn main() -> Result<(), Box<dyn Error>> {
 
     let mut db_conn: db::DbHandle = db::DbHandle::new(&args.flag_db);
 
+    let master_key: [u8; 32] = get_master_key(&mut db_conn);
+
     Ok(())
 }