Rewrite entire codebase to split into client and server

src/main.rs

@@ -1,42 +1,69 @@
 #[macro_use]
 extern crate prettytable;
 
-use core::common::CommandStatus;
-#[cfg(feature = "mysql-admutils-compatibility")]
+use clap::Parser;
+
 use std::path::PathBuf;
 
+use std::os::unix::net::UnixStream as StdUnixStream;
+use tokio::net::UnixStream as TokioUnixStream;
+
+use crate::{
+    core::{
+        bootstrap::{bootstrap_server_connection_and_drop_privileges, drop_privs},
+        protocol::create_client_to_server_message_stream,
+    },
+    server::command::ServerArgs,
+};
+
 #[cfg(feature = "mysql-admutils-compatibility")]
 use crate::cli::mysql_admutils_compatibility::{mysql_dbadm, mysql_useradm};
 
-use clap::Parser;
+mod server;
 
-mod authenticated_unix_socket;
 mod cli;
 mod core;
 
 #[cfg(feature = "tui")]
 mod tui;
 
-#[derive(Parser)]
+#[derive(Parser, Debug)]
 struct Args {
     #[command(subcommand)]
     command: Command,
 
-    #[command(flatten)]
-    config_overrides: core::config::GlobalConfigArgs,
+    /// Path to the socket of the server, if it already exists.
+    #[arg(
+        short,
+        long,
+        value_name = "PATH",
+        global = true,
+        hide_short_help = true
+    )]
+    server_socket_path: Option<PathBuf>,
+
+    /// Config file to use for the server.
+    #[arg(
+        short,
+        long,
+        value_name = "PATH",
+        global = true,
+        hide_short_help = true
+    )]
+    config: Option<PathBuf>,
 
     #[cfg(feature = "tui")]
     #[arg(short, long, alias = "tui", global = true)]
     interactive: bool,
 }
 
-/// Database administration tool for non-admin users to manage their own MySQL databases and users.
-///
-/// This tool allows you to manage users and databases in MySQL.
-///
-/// You are only allowed to manage databases and users that are prefixed with
-/// either your username, or a group that you are a member of.
-#[derive(Parser)]
+// Database administration tool for non-admin users to manage their own MySQL databases and users.
+//
+// This tool allows you to manage users and databases in MySQL.
+//
+// You are only allowed to manage databases and users that are prefixed with
+// either your username, or a group that you are a member of.
+#[derive(Parser, Debug, Clone)]
 #[command(version, about, disable_help_subcommand = true)]
 enum Command {
     #[command(flatten)]
@@ -44,10 +71,18 @@ enum Command {
 
     #[command(flatten)]
     User(cli::user_command::UserCommand),
+
+    #[command(hide = true)]
+    Server(server::command::ServerArgs),
 }
 
-#[tokio::main(flavor = "current_thread")]
-async fn main() -> anyhow::Result<()> {
+// TODO: tag all functions that are run with elevated privileges with
+//       comments emphasizing the need for caution.
+
+fn main() -> anyhow::Result<()> {
+    // TODO: find out if there are any security risks of running
+    //       env_logger and clap with elevated privileges.
+
     env_logger::init();
 
     #[cfg(feature = "mysql-admutils-compatibility")]
@@ -59,42 +94,60 @@ async fn main() -> anyhow::Result<()> {
         });
 
         match argv0.as_deref() {
-            Some("mysql-dbadm") => return mysql_dbadm::main().await,
-            Some("mysql-useradm") => return mysql_useradm::main().await,
+            Some("mysql-dbadm") => return mysql_dbadm::main(),
+            Some("mysql-useradm") => return mysql_useradm::main(),
             _ => { /* fall through */ }
         }
     }
 
     let args: Args = Args::parse();
-    let config = core::config::get_config(args.config_overrides)?;
-    let connection = core::config::create_mysql_connection_from_config(config.mysql).await?;
-
-    let result = match args.command {
-        Command::Db(command) => cli::database_command::handle_command(command, connection).await,
-        Command::User(user_args) => cli::user_command::handle_command(user_args, connection).await,
-    };
-
-    match result {
-        Ok(CommandStatus::SuccessfullyModified) => {
-            println!("Modifications committed successfully");
-            Ok(())
+    match args.command {
+        Command::Server(ref command) => {
+            drop_privs()?;
+            tokio_start_server(args.server_socket_path, args.config, command.clone())?;
+            return Ok(());
         }
-        Ok(CommandStatus::PartiallySuccessfullyModified) => {
-            println!("Some modifications committed successfully");
-            Ok(())
-        }
-        Ok(CommandStatus::NoModificationsNeeded) => {
-            println!("No modifications made");
-            Ok(())
-        }
-        Ok(CommandStatus::NoModificationsIntended) => {
-            /* Don't report anything */
-            Ok(())
-        }
-        Ok(CommandStatus::Cancelled) => {
-            println!("Command cancelled successfully");
-            Ok(())
-        }
-        Err(e) => Err(e),
+        _ => { /* fall through */ }
     }
+
+    let server_connection =
+        bootstrap_server_connection_and_drop_privileges(args.server_socket_path, args.config)?;
+
+    tokio_run_command(args.command, server_connection)?;
+
+    Ok(())
+}
+
+fn tokio_start_server(
+    server_socket_path: Option<PathBuf>,
+    config_path: Option<PathBuf>,
+    args: ServerArgs,
+) -> anyhow::Result<()> {
+    tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .unwrap()
+        .block_on(async {
+            server::command::handle_command(server_socket_path, config_path, args).await
+        })
+}
+
+fn tokio_run_command(command: Command, server_connection: StdUnixStream) -> anyhow::Result<()> {
+    tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .unwrap()
+        .block_on(async {
+            let tokio_socket = TokioUnixStream::from_std(server_connection)?;
+            let message_stream = create_client_to_server_message_stream(tokio_socket);
+            match command {
+                Command::User(user_args) => {
+                    cli::user_command::handle_command(user_args, message_stream).await
+                }
+                Command::Db(db_args) => {
+                    cli::database_command::handle_command(db_args, message_stream).await
+                }
+                Command::Server(_) => unreachable!(),
+            }
+        })
 }