Cargo.lock

@@ -1077,6 +1077,7 @@ dependencies = [
  "prettytable",
  "rand",
  "ratatui",
+ "regex",
  "sd-notify",
  "serde",
  "serde_json",

Cargo.toml

@@ -49,3 +49,6 @@ codegen-units = 1
 
 [build-dependencies]
 anyhow = "1.0.82"
+
+[dev-dependencies]
+regex = "1.10.6"

example-config.toml

@@ -1,8 +1,22 @@
 # This should go to `/etc/mysqladm/config.toml`
 
+[server]
+# Note that this gets ignored if you are using socket activation.
+socket_path = "/var/run/mysqladm/mysqladm.sock"
+
 [mysql]
+
+# if you use a socket, the host and port will be ignored
+# socket_path = "/var/run/mysql/mysql.sock"
+
 host = "localhost"
 port = 3306
+
+# The username and password can be omitted if you are using
+# socket based authentication. However, the vendored systemd
+# service is running as DynamicUser, so by default you need
+# to at least specify the username.
 username = "root"
 password = "secret"
+
 timeout = 2 # seconds

flake.lock

@@ -2,16 +2,16 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1723637854,
-        "narHash": "sha256-med8+5DSWa2UnOqtdICndjDAEjxr5D7zaIiK4pn0Q7c=",
+        "lastModified": 1723938990,
+        "narHash": "sha256-9tUadhnZQbWIiYVXH8ncfGXGvkNq3Hag4RCBEMUk7MI=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "c3aa7b8938b17aebd2deecf7be0636000d62a2b9",
+        "rev": "c42fcfbdfeae23e68fc520f9182dde9f38ad1890",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixos-unstable",
+        "ref": "nixos-24.05",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -29,11 +29,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1723947704,
-        "narHash": "sha256-TcVf66N2NgGhxORFytzgqWcg0XJ+kk8uNLNsTRI5sYM=",
+        "lastModified": 1724034091,
+        "narHash": "sha256-b1g7w0sw+MDAhUAeCoX1vlTghsqcDZkxr+k9OZmxPa8=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "456e78a55feade2c3bc6d7bc0bf5e710c9d86120",
+        "rev": "c7d36e0947826e0751a5214ffe82533fbc909bc0",
         "type": "github"
       },
       "original": {

flake.nix

@@ -1,6 +1,6 @@
 {
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
 
     rust-overlay.url = "github:oxalica/rust-overlay";
     rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
@@ -52,11 +52,16 @@
 
     overlays = {
       default = self.overlays.mysqladm-rs;
-      greg-ng = final: prev: {
+      mysqladm-rs = final: prev: {
         inherit (self.packages.${prev.system}) mysqladm-rs;
       };
     };
 
+    nixosModules = {
+      default = self.nixosModules.mysqladm-rs;
+      mysqladm-rs = import ./nix/module.nix;
+    };
+
     packages = let
       cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
       cargoLock = ./Cargo.lock;

nix/module.nix

@@ -0,0 +1,141 @@
+{ config, pkgs, lib, ... }:
+let
+  cfg = config.services.mysqladm-rs;
+  format = pkgs.formats.toml { };
+in
+{
+  options.services.mysqladm-rs = {
+    enable = lib.mkEnableOption "Enable mysqladm-rs";
+
+    package = lib.mkPackageOption pkgs "mysqladm-rs" { };
+
+    createLocalDatabaseUser = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = "Create a local database user for mysqladm-rs";
+    };
+
+    settings = lib.mkOption {
+      default = { };
+      type = lib.types.submodule {
+        freeformType = format.type;
+        options  = {
+          server = {
+            socket_path = lib.mkOption {
+              type = lib.types.path;
+              default = "/var/run/mysqladm/mysqladm.sock";
+              description = "Path to the MySQL socket";
+            };
+          };
+
+          mysql = {
+            socket_path = lib.mkOption {
+              type = with lib.types; nullOr path;
+              default = "/var/run/mysqld/mysqld.sock";
+              description = "Path to the MySQL socket";
+            };
+            host = lib.mkOption {
+              type = with lib.types; nullOr str;
+              default = null;
+              description = "MySQL host";
+            };
+            port = lib.mkOption {
+              type = with lib.types; nullOr port;
+              default = 3306;
+              description = "MySQL port";
+            };
+            username = lib.mkOption {
+              type = lib.types.str;
+              default = "mysqladm";
+              description = "MySQL username";
+            };
+            passwordFile = lib.mkOption {
+              type = with lib.types; nullOr path;
+              default = null;
+              description = "Path to a file containing the MySQL password";
+            };
+            timeout = lib.mkOption {
+              type = lib.types.ints.positive;
+              default = 2;
+              description = "Number of seconds to wait for a response from the MySQL server";
+            };
+          };
+        };
+      };
+    };
+  };
+
+  config = let
+    nullStrippedConfig = lib.filterAttrsRecursive (_: v: v != null) cfg.settings;
+    configFile = format.generate "mysqladm-rs.conf" nullStrippedConfig;
+  in lib.mkIf config.services.mysqladm-rs.enable {
+    environment.systemPackages = [ cfg.package ];
+
+    services.mysql.ensureUsers = lib.mkIf cfg.createLocalDatabaseUser [
+      {
+        name = cfg.settings.mysql.username;
+        ensurePermissions = {
+          "mysql.*" = "SELECT, INSERT, UPDATE, DELETE";
+          "*.*" = "CREATE USER, GRANT OPTION";
+        };
+      }
+    ];
+
+    systemd.services."mysqladm@" = {
+      description = "MySQL administration tool for non-admin users";
+      environment.RUST_LOG = "debug";
+      serviceConfig = {
+        Type = "notify";
+        ExecStart = "${lib.getExe cfg.package} server socket-activate --config ${configFile}";
+
+        User = "mysqladm";
+        Group = "mysqladm";
+        DynamicUser = true;
+
+        # This is required to read unix user/group details.
+        PrivateUsers = false;
+
+        CapabilityBoundingSet = "";
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        PrivateMounts = true;
+        PrivateTmp = "yes";
+        ProcSubset = "pid";
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        ProtectSystem = "strict";
+        RemoveIPC = true;
+        UMask = "0000";
+        RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [
+          "@system-service"
+          "~@privileged"
+          "~@resources"
+        ];
+      };
+    };
+
+    systemd.sockets."mysqladm" = {
+      description = "MySQL administration tool for non-admin users";
+      wantedBy = [ "sockets.target" ];
+      restartTriggers = [ configFile ];
+      socketConfig = {
+        ListenStream = cfg.settings.server.socket_path;
+        Accept = "yes";
+        PassCredentials = true;
+      };
+    };
+  };
+}

src/cli/mysql_admutils_compatibility/mysql_dbadm.rs

@@ -56,11 +56,11 @@ The Y/N-values corresponds to the following mysql privileges:
 /// Please consider using the newer mysqladm command instead.
 #[derive(Parser)]
 #[command(
-  bin_name = "mysql-dbadm",
-  version,
-  about,
-  disable_help_subcommand = true,
-  verbatim_doc_comment,
+    bin_name = "mysql-dbadm",
+    version,
+    about,
+    disable_help_subcommand = true,
+    verbatim_doc_comment
 )]
 pub struct Args {
     #[command(subcommand)]

src/cli/mysql_admutils_compatibility/mysql_useradm.rs

@@ -32,11 +32,11 @@ use crate::{
 /// Please consider using the newer mysqladm command instead.
 #[derive(Parser)]
 #[command(
-  bin_name = "mysql-useradm",
-  version,
-  about,
-  disable_help_subcommand = true,
-  verbatim_doc_comment,
+    bin_name = "mysql-useradm",
+    version,
+    about,
+    disable_help_subcommand = true,
+    verbatim_doc_comment
 )]
 pub struct Args {
     #[command(subcommand)]

src/cli/user_command.rs

@@ -140,6 +140,7 @@ async fn create_users(
                     "Do you want to set a password for user '{}'?",
                     username
                 ))
+                .default(false)
                 .interact()?
         {
             let password = read_password_from_stdin_with_double_check(username)?;

src/core/bootstrap.rs

@@ -7,7 +7,7 @@ use tokio::net::UnixStream as TokioUnixStream;
 
 use crate::{
     core::common::{UnixUser, DEFAULT_CONFIG_PATH, DEFAULT_SOCKET_PATH},
-    server::{config::read_config_form_path, server_loop::handle_requests_for_single_session},
+    server::{config::read_config_from_path, server_loop::handle_requests_for_single_session},
 };
 
 // TODO: this function is security critical, it should be integration tested
@@ -32,15 +32,18 @@ pub fn drop_privs() -> anyhow::Result<()> {
 
 /// This function is used to bootstrap the connection to the server.
 /// This can happen in two ways:
+///
 /// 1. If a socket path is provided, or exists in the default location,
 ///    the function will connect to the socket and authenticate with the
 ///    server to ensure that the server knows the uid of the client.
+///
 /// 2. If a config path is provided, or exists in the default location,
 ///    and the config is readable, the function will assume it is either
 ///    setuid or setgid, and will fork a child process to run the server
 ///    with the provided config. The server will exit silently by itself
 ///    when it is done, and this function will only return for the client
 ///    with the socket for the server.
+///
 /// If neither of these options are available, the function will fail.
 pub fn bootstrap_server_connection_and_drop_privileges(
     server_socket_path: Option<PathBuf>,
@@ -140,7 +143,7 @@ fn run_forked_server(
     server_socket: StdUnixStream,
     unix_user: UnixUser,
 ) -> anyhow::Result<()> {
-    let config = read_config_form_path(Some(config_path))?;
+    let config = read_config_from_path(Some(config_path))?;
 
     let result: anyhow::Result<()> = tokio::runtime::Builder::new_current_thread()
         .enable_all()

src/core/database_privileges.rs

@@ -14,8 +14,8 @@ use crate::server::sql::database_privilege_operations::{
 
 pub fn db_priv_field_human_readable_name(name: &str) -> String {
     match name {
-        "db" => "Database".to_owned(),
-        "user" => "User".to_owned(),
+        "Db" => "Database".to_owned(),
+        "User" => "User".to_owned(),
         "select_priv" => "Select".to_owned(),
         "insert_priv" => "Insert".to_owned(),
         "update_priv" => "Update".to_owned(),
@@ -128,8 +128,8 @@ pub fn format_privileges_line_for_editor(
     DATABASE_PRIVILEGE_FIELDS
         .into_iter()
         .map(|field| match field {
-            "db" => format!("{:width$}", privs.db, width = database_name_len),
-            "user" => format!("{:width$}", privs.user, width = username_len),
+            "Db" => format!("{:width$}", privs.db, width = database_name_len),
+            "User" => format!("{:width$}", privs.user, width = username_len),
             privilege => format!(
                 "{:width$}",
                 yn(privs.get_privilege_by_name(privilege)),

src/core/protocol/request_response.rs

@@ -73,7 +73,6 @@ pub enum Response {
     UnlockUsers(UnlockUsersOutput),
 
     // Generic responses
-    OperationAborted,
+    Ready,
     Error(String),
-    Exit,
 }

src/main.rs

@@ -9,10 +9,12 @@ use std::path::PathBuf;
 use std::os::unix::net::UnixStream as StdUnixStream;
 use tokio::net::UnixStream as TokioUnixStream;
 
+use futures::StreamExt;
+
 use crate::{
     core::{
-        bootstrap::{bootstrap_server_connection_and_drop_privileges, drop_privs},
-        protocol::create_client_to_server_message_stream,
+        bootstrap::bootstrap_server_connection_and_drop_privileges,
+        protocol::{create_client_to_server_message_stream, Response},
     },
     server::command::ServerArgs,
 };
@@ -107,17 +109,17 @@ fn main() -> anyhow::Result<()> {
     env_logger::init();
 
     #[cfg(feature = "mysql-admutils-compatibility")]
-    if let Some(_) = handle_mysql_admutils_command()? {
+    if handle_mysql_admutils_command()?.is_some() {
         return Ok(());
     }
 
     let args: Args = Args::parse();
 
-    if let Some(_) = handle_server_command(&args)? {
+    if handle_server_command(&args)?.is_some() {
         return Ok(());
     }
 
-    if let Some(_) = handle_generate_completions_command(&args)? {
+    if handle_generate_completions_command(&args)?.is_some() {
         return Ok(());
     }
 
@@ -137,8 +139,8 @@ fn handle_mysql_admutils_command() -> anyhow::Result<Option<()>> {
     });
 
     match argv0.as_deref() {
-        Some("mysql-dbadm") => mysql_dbadm::main().map(|result| Some(result)),
-        Some("mysql-useradm") => mysql_useradm::main().map(|result| Some(result)),
+        Some("mysql-dbadm") => mysql_dbadm::main().map(Some),
+        Some("mysql-useradm") => mysql_useradm::main().map(Some),
         _ => Ok(None),
     }
 }
@@ -146,7 +148,6 @@ fn handle_mysql_admutils_command() -> anyhow::Result<Option<()>> {
 fn handle_server_command(args: &Args) -> anyhow::Result<Option<()>> {
     match args.command {
         Command::Server(ref command) => {
-            drop_privs()?;
             tokio_start_server(
                 args.server_socket_path.clone(),
                 args.config.clone(),
@@ -205,7 +206,20 @@ fn tokio_run_command(command: Command, server_connection: StdUnixStream) -> anyh
         .unwrap()
         .block_on(async {
             let tokio_socket = TokioUnixStream::from_std(server_connection)?;
-            let message_stream = create_client_to_server_message_stream(tokio_socket);
+            let mut message_stream = create_client_to_server_message_stream(tokio_socket);
+
+            while let Some(Ok(message)) = message_stream.next().await {
+                match message {
+                    Response::Error(err) => {
+                        anyhow::bail!("{}", err);
+                    }
+                    Response::Ready => break,
+                    message => {
+                        eprintln!("Unexpected message from server: {:?}", message);
+                    }
+                }
+            }
+
             match command {
                 Command::User(user_args) => {
                     cli::user_command::handle_command(user_args, message_stream).await

src/server/common.rs

@@ -1,11 +1,51 @@
 use crate::core::common::UnixUser;
+use sqlx::prelude::*;
 
 /// This function creates a regex that matches items (users, databases)
 /// that belong to the user or any of the user's groups.
 pub fn create_user_group_matching_regex(user: &UnixUser) -> String {
     if user.groups.is_empty() {
-        format!("{}(_.+)?", user.username)
+        format!("{}_.+", user.username)
     } else {
-        format!("({}|{})(_.+)?", user.username, user.groups.join("|"))
+        format!("({}|{})_.+", user.username, user.groups.join("|"))
     }
 }
+
+/// Some mysql versions with some collations mark some columns as binary fields,
+/// which in the current version of sqlx is not parsable as string.
+/// See: https://github.com/launchbadge/sqlx/issues/3387
+#[inline]
+pub fn try_get_with_binary_fallback(
+    row: &sqlx::mysql::MySqlRow,
+    column: &str,
+) -> Result<String, sqlx::Error> {
+    row.try_get(column).or_else(|_| {
+        row.try_get::<Vec<u8>, _>(column)
+            .map(|v| String::from_utf8_lossy(&v).to_string())
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use regex::Regex;
+
+    #[test]
+    fn test_create_user_group_matching_regex() {
+        let user = UnixUser {
+            username: "user".to_owned(),
+            groups: vec!["group1".to_owned(), "group2".to_owned()],
+        };
+
+        let regex = create_user_group_matching_regex(&user);
+        let re = Regex::new(&regex).unwrap();
+
+        assert!(re.is_match("user_something"));
+        assert!(re.is_match("group1_something"));
+        assert!(re.is_match("group2_something"));
+
+        assert!(!re.is_match("other_something"));
+        assert!(!re.is_match("user"));
+        assert!(!re.is_match("usersomething"));
+    }
+}

src/server/config.rs

@@ -21,21 +21,37 @@ pub struct ServerConfig {
 #[derive(Debug, Clone, Deserialize, Serialize)]
 #[serde(rename = "mysql")]
 pub struct MysqlConfig {
-    pub host: String,
+    pub socket_path: Option<PathBuf>,
+    pub host: Option<String>,
     pub port: Option<u16>,
-    pub username: String,
-    pub password: String,
+    pub username: Option<String>,
+    pub password: Option<String>,
+    pub password_file: Option<PathBuf>,
     pub timeout: Option<u64>,
 }
 
 #[derive(Parser, Debug, Clone)]
 pub struct ServerConfigArgs {
+    /// Path to the socket of the MySQL server.
+    #[arg(long, value_name = "PATH", global = true)]
+    socket_path: Option<PathBuf>,
+
     /// Hostname of the MySQL server.
-    #[arg(long, value_name = "HOST", global = true)]
+    #[arg(
+        long,
+        value_name = "HOST",
+        global = true,
+        conflicts_with = "socket_path"
+    )]
     mysql_host: Option<String>,
 
     /// Port of the MySQL server.
-    #[arg(long, value_name = "PORT", global = true)]
+    #[arg(
+        long,
+        value_name = "PORT",
+        global = true,
+        conflicts_with = "socket_path"
+    )]
     mysql_port: Option<u16>,
 
     /// Username to use for the MySQL connection.
@@ -44,7 +60,7 @@ pub struct ServerConfigArgs {
 
     /// Path to a file containing the MySQL password.
     #[arg(long, value_name = "PATH", global = true)]
-    mysql_password_file: Option<String>,
+    mysql_password_file: Option<PathBuf>,
 
     /// Seconds to wait for the MySQL connection to be established.
     #[arg(long, value_name = "SECONDS", global = true)]
@@ -57,30 +73,40 @@ pub fn read_config_from_path_with_arg_overrides(
     config_path: Option<PathBuf>,
     args: ServerConfigArgs,
 ) -> anyhow::Result<ServerConfig> {
-    let config = read_config_form_path(config_path)?;
+    let config = read_config_from_path(config_path)?;
 
-    let mysql = &config.mysql;
+    let mysql = config.mysql;
 
-    let password = if let Some(path) = args.mysql_password_file {
-        fs::read_to_string(path)
-            .context("Failed to read MySQL password file")
-            .map(|s| s.trim().to_owned())?
+    let password = if let Some(path) = &args.mysql_password_file {
+        Some(
+            fs::read_to_string(path)
+                .context("Failed to read MySQL password file")
+                .map(|s| s.trim().to_owned())?,
+        )
+    } else if let Some(path) = &mysql.password_file {
+        Some(
+            fs::read_to_string(path)
+                .context("Failed to read MySQL password file")
+                .map(|s| s.trim().to_owned())?,
+        )
     } else {
         mysql.password.to_owned()
     };
 
     Ok(ServerConfig {
         mysql: MysqlConfig {
-            host: args.mysql_host.unwrap_or(mysql.host.to_owned()),
+            socket_path: args.socket_path.or(mysql.socket_path),
+            host: args.mysql_host.or(mysql.host),
             port: args.mysql_port.or(mysql.port),
-            username: args.mysql_user.unwrap_or(mysql.username.to_owned()),
+            username: args.mysql_user.or(mysql.username.to_owned()),
             password,
+            password_file: args.mysql_password_file.or(mysql.password_file),
             timeout: args.mysql_connect_timeout.or(mysql.timeout),
         },
     })
 }
 
-pub fn read_config_form_path(config_path: Option<PathBuf>) -> anyhow::Result<ServerConfig> {
+pub fn read_config_from_path(config_path: Option<PathBuf>) -> anyhow::Result<ServerConfig> {
     let config_path = config_path.unwrap_or_else(|| PathBuf::from(DEFAULT_CONFIG_PATH));
 
     log::debug!("Reading config from {:?}", &config_path);
@@ -97,30 +123,52 @@ pub fn read_config_form_path(config_path: Option<PathBuf>) -> anyhow::Result<Ser
         ))
 }
 
-/// Use the provided configuration to establish a connection to a MySQL server.
-pub async fn create_mysql_connection_from_config(
-    config: &MysqlConfig,
-) -> anyhow::Result<MySqlConnection> {
+fn log_config(config: &MysqlConfig) {
     let mut display_config = config.clone();
-    "<REDACTED>".clone_into(&mut display_config.password);
+    display_config.password = display_config
+        .password
+        .as_ref()
+        .map(|_| "<REDACTED>".to_owned());
     log::debug!(
         "Connecting to MySQL server with parameters: {:#?}",
         display_config
     );
+}
+
+/// Use the provided configuration to establish a connection to a MySQL server.
+pub async fn create_mysql_connection_from_config(
+    config: &MysqlConfig,
+) -> anyhow::Result<MySqlConnection> {
+    log_config(config);
+
+    let mut mysql_options = MySqlConnectOptions::new().database("mysql");
+
+    if let Some(username) = &config.username {
+        mysql_options = mysql_options.username(username);
+    }
+
+    if let Some(password) = &config.password {
+        mysql_options = mysql_options.password(password);
+    }
+
+    if let Some(socket_path) = &config.socket_path {
+        mysql_options = mysql_options.socket(socket_path);
+    } else if let Some(host) = &config.host {
+        mysql_options = mysql_options.host(host);
+        mysql_options = mysql_options.port(config.port.unwrap_or(DEFAULT_PORT));
+    } else {
+        anyhow::bail!("No MySQL host or socket path provided");
+    }
 
     match tokio::time::timeout(
         Duration::from_secs(config.timeout.unwrap_or(DEFAULT_TIMEOUT)),
-        MySqlConnectOptions::new()
-            .host(&config.host)
-            .username(&config.username)
-            .password(&config.password)
-            .port(config.port.unwrap_or(DEFAULT_PORT))
-            .database("mysql")
-            .connect(),
+        mysql_options.connect(),
     )
     .await
     {
-        Ok(connection) => connection.context("Failed to connect to MySQL"),
-        Err(_) => Err(anyhow!("Timed out after 2 seconds")).context("Failed to connect to MySQL"),
+        Ok(connection) => connection.context("Failed to connect to the database"),
+        Err(_) => {
+            Err(anyhow!("Timed out after 2 seconds")).context("Failed to connect to the database")
+        }
     }
 }

src/server/server_loop.rs

@@ -1,7 +1,7 @@
 use std::{collections::BTreeSet, fs, path::PathBuf};
 
 use futures_util::{SinkExt, StreamExt};
-use tokio::io::AsyncWriteExt;
+use indoc::concatdoc;
 use tokio::net::{UnixListener, UnixStream};
 
 use sqlx::prelude::*;
@@ -57,15 +57,43 @@ pub async fn listen_for_incoming_connections(
 
     sd_notify::notify(true, &[sd_notify::NotifyState::Ready]).ok();
 
-    while let Ok((mut conn, _addr)) = listener.accept().await {
-        let uid = conn.peer_cred()?.uid();
+    while let Ok((conn, _addr)) = listener.accept().await {
+        let uid = match conn.peer_cred() {
+            Ok(cred) => cred.uid(),
+            Err(e) => {
+                log::error!("Failed to get peer credentials from socket: {}", e);
+                let mut message_stream = create_server_to_client_message_stream(conn);
+                message_stream
+                    .send(Response::Error(
+                        (concatdoc! {
+                            "Server failed to get peer credentials from socket\n",
+                            "Please check the server logs or contact the system administrators"
+                        })
+                        .to_string(),
+                    ))
+                    .await
+                    .ok();
+                continue;
+            }
+        };
+
         log::trace!("Accepted connection from uid {}", uid);
 
         let unix_user = match UnixUser::from_uid(uid) {
             Ok(user) => user,
             Err(e) => {
-                eprintln!("Failed to get UnixUser from uid: {}", e);
-                conn.shutdown().await?;
+                log::error!("Failed to get username from uid: {}", e);
+                let mut message_stream = create_server_to_client_message_stream(conn);
+                message_stream
+                    .send(Response::Error(
+                        (concatdoc! {
+                            "Server failed to get user data from the system\n",
+                            "Please check the server logs or contact the system administrators"
+                        })
+                        .to_string(),
+                    ))
+                    .await
+                    .ok();
                 continue;
             }
         };
@@ -73,9 +101,9 @@ pub async fn listen_for_incoming_connections(
         log::info!("Accepted connection from {}", unix_user.username);
 
         match handle_requests_for_single_session(conn, &unix_user, &config).await {
-            Ok(_) => {}
+            Ok(()) => {}
             Err(e) => {
-                eprintln!("Failed to run server: {}", e);
+                log::error!("Failed to run server: {}", e);
             }
         }
     }
@@ -88,8 +116,24 @@ pub async fn handle_requests_for_single_session(
     unix_user: &UnixUser,
     config: &ServerConfig,
 ) -> anyhow::Result<()> {
-    let message_stream = create_server_to_client_message_stream(socket);
-    let mut db_connection = create_mysql_connection_from_config(&config.mysql).await?;
+    let mut message_stream = create_server_to_client_message_stream(socket);
+    let mut db_connection = match create_mysql_connection_from_config(&config.mysql).await {
+        Ok(connection) => connection,
+        Err(err) => {
+            message_stream
+                .send(Response::Error(
+                    (concatdoc! {
+                        "Server failed to connect to database\n",
+                        "Please check the server logs or contact the system administrators"
+                    })
+                    .to_string(),
+                ))
+                .await?;
+            message_stream.flush().await?;
+            return Err(err);
+        }
+    };
+
     log::debug!("Successfully connected to database");
 
     let result = handle_requests_for_single_session_with_db_connection(
@@ -100,9 +144,9 @@ pub async fn handle_requests_for_single_session(
     .await;
 
     if let Err(e) = db_connection.close().await {
-        eprintln!("Failed to close database connection: {}", e);
-        eprintln!("{}", e);
-        eprintln!("Ignoring...");
+        log::error!("Failed to close database connection: {}", e);
+        log::error!("{}", e);
+        log::error!("Ignoring...");
     }
 
     result
@@ -116,6 +160,7 @@ pub async fn handle_requests_for_single_session_with_db_connection(
     unix_user: &UnixUser,
     db_connection: &mut MySqlConnection,
 ) -> anyhow::Result<()> {
+    stream.send(Response::Ready).await?;
     loop {
         // TODO: better error handling
         let request = match stream.next().await {
@@ -133,17 +178,14 @@ pub async fn handle_requests_for_single_session_with_db_connection(
             Request::CreateDatabases(databases_names) => {
                 let result = create_databases(databases_names, unix_user, db_connection).await;
                 stream.send(Response::CreateDatabases(result)).await?;
-                stream.flush().await?;
             }
             Request::DropDatabases(databases_names) => {
                 let result = drop_databases(databases_names, unix_user, db_connection).await;
                 stream.send(Response::DropDatabases(result)).await?;
-                stream.flush().await?;
             }
             Request::ListDatabases => {
                 let result = list_databases_for_user(unix_user, db_connection).await;
                 stream.send(Response::ListAllDatabases(result)).await?;
-                stream.flush().await?;
             }
             Request::ListPrivileges(database_names) => {
                 let response = match database_names {
@@ -161,7 +203,6 @@ pub async fn handle_requests_for_single_session_with_db_connection(
                 };
 
                 stream.send(response).await?;
-                stream.flush().await?;
             }
             Request::ModifyPrivileges(database_privilege_diffs) => {
                 let result = apply_privilege_diffs(
@@ -171,24 +212,20 @@ pub async fn handle_requests_for_single_session_with_db_connection(
                 )
                 .await;
                 stream.send(Response::ModifyPrivileges(result)).await?;
-                stream.flush().await?;
             }
             Request::CreateUsers(db_users) => {
                 let result = create_database_users(db_users, unix_user, db_connection).await;
                 stream.send(Response::CreateUsers(result)).await?;
-                stream.flush().await?;
             }
             Request::DropUsers(db_users) => {
                 let result = drop_database_users(db_users, unix_user, db_connection).await;
                 stream.send(Response::DropUsers(result)).await?;
-                stream.flush().await?;
             }
             Request::PasswdUser(db_user, password) => {
                 let result =
                     set_password_for_database_user(&db_user, &password, unix_user, db_connection)
                         .await;
                 stream.send(Response::PasswdUser(result)).await?;
-                stream.flush().await?;
             }
             Request::ListUsers(db_users) => {
                 let response = match db_users {
@@ -203,22 +240,21 @@ pub async fn handle_requests_for_single_session_with_db_connection(
                     }
                 };
                 stream.send(response).await?;
-                stream.flush().await?;
             }
             Request::LockUsers(db_users) => {
                 let result = lock_database_users(db_users, unix_user, db_connection).await;
                 stream.send(Response::LockUsers(result)).await?;
-                stream.flush().await?;
             }
             Request::UnlockUsers(db_users) => {
                 let result = unlock_database_users(db_users, unix_user, db_connection).await;
                 stream.send(Response::UnlockUsers(result)).await?;
-                stream.flush().await?;
             }
             Request::Exit => {
                 break;
             }
         }
+
+        stream.flush().await?;
     }
 
     Ok(())

src/server/sql/database_privilege_operations.rs

@@ -32,7 +32,7 @@ use crate::{
         },
     },
     server::{
-        common::create_user_group_matching_regex,
+        common::{create_user_group_matching_regex, try_get_with_binary_fallback},
         input_sanitization::{quote_identifier, validate_name, validate_ownership_by_unix_user},
         sql::database_operations::unsafe_database_exists,
     },
@@ -42,8 +42,8 @@ use crate::{
 /// from the `db` table in the database. If you need to add or remove privilege
 /// fields, this is a good place to start.
 pub const DATABASE_PRIVILEGE_FIELDS: [&str; 13] = [
-    "db",
-    "user",
+    "Db",
+    "User",
     "select_priv",
     "insert_priv",
     "update_priv",
@@ -97,6 +97,8 @@ impl DatabasePrivilegeRow {
     }
 }
 
+// TODO: get by name instead of row tuple position
+
 #[inline]
 fn get_mysql_row_priv_field(row: &MySqlRow, position: usize) -> Result<bool, sqlx::Error> {
     let field = DATABASE_PRIVILEGE_FIELDS[position];
@@ -113,8 +115,8 @@ fn get_mysql_row_priv_field(row: &MySqlRow, position: usize) -> Result<bool, sql
 impl FromRow<'_, MySqlRow> for DatabasePrivilegeRow {
     fn from_row(row: &MySqlRow) -> Result<Self, sqlx::Error> {
         Ok(Self {
-            db: row.try_get("db")?,
-            user: row.try_get("user")?,
+            db: try_get_with_binary_fallback(row, "Db")?,
+            user: try_get_with_binary_fallback(row, "User")?,
             select_priv: get_mysql_row_priv_field(row, 2)?,
             insert_priv: get_mysql_row_priv_field(row, 3)?,
             update_priv: get_mysql_row_priv_field(row, 4)?,
@@ -137,7 +139,7 @@ async fn unsafe_get_database_privileges(
     connection: &mut MySqlConnection,
 ) -> Result<Vec<DatabasePrivilegeRow>, sqlx::Error> {
     let result = sqlx::query_as::<_, DatabasePrivilegeRow>(&format!(
-        "SELECT {} FROM `db` WHERE `db` = ?",
+        "SELECT {} FROM `db` WHERE `Db` = ?",
         DATABASE_PRIVILEGE_FIELDS
             .iter()
             .map(|field| quote_identifier(field))
@@ -166,7 +168,7 @@ pub async fn unsafe_get_database_privileges_for_db_user_pair(
     connection: &mut MySqlConnection,
 ) -> Result<Option<DatabasePrivilegeRow>, sqlx::Error> {
     let result = sqlx::query_as::<_, DatabasePrivilegeRow>(&format!(
-        "SELECT {} FROM `db` WHERE `db` = ? AND `user` = ?",
+        "SELECT {} FROM `db` WHERE `Db` = ? AND `User` = ?",
         DATABASE_PRIVILEGE_FIELDS
             .iter()
             .map(|field| quote_identifier(field))
@@ -316,7 +318,7 @@ async fn unsafe_apply_privilege_diff(
                 .join(",");
 
             sqlx::query(
-                format!("UPDATE `db` SET {} WHERE `db` = ? AND `user` = ?", changes).as_str(),
+                format!("UPDATE `db` SET {} WHERE `Db` = ? AND `User` = ?", changes).as_str(),
             )
             .bind(p.db.to_string())
             .bind(p.user.to_string())
@@ -325,7 +327,7 @@ async fn unsafe_apply_privilege_diff(
             .map(|_| ())
         }
         DatabasePrivilegesDiff::Deleted(p) => {
-            sqlx::query("DELETE FROM `db` WHERE `db` = ? AND `user` = ?")
+            sqlx::query("DELETE FROM `db` WHERE `Db` = ? AND `User` = ?")
                 .bind(p.db.to_string())
                 .bind(p.user.to_string())
                 .execute(connection)

src/server/sql/user_operations.rs

@@ -7,6 +7,7 @@ use serde::{Deserialize, Serialize};
 use sqlx::prelude::*;
 use sqlx::MySqlConnection;
 
+use crate::server::common::try_get_with_binary_fallback;
 use crate::{
     core::{
         common::UnixUser,
@@ -350,20 +351,6 @@ pub struct DatabaseUser {
     pub databases: Vec<String>,
 }
 
-/// Some mysql versions with some collations mark some columns as binary fields,
-/// which in the current version of sqlx is not parsable as string.
-/// See: https://github.com/launchbadge/sqlx/issues/3387
-#[inline]
-fn try_get_with_binary_fallback(
-    row: &sqlx::mysql::MySqlRow,
-    column: &str,
-) -> Result<String, sqlx::Error> {
-    row.try_get(column).or_else(|_| {
-        row.try_get::<Vec<u8>, _>(column)
-            .map(|v| String::from_utf8_lossy(&v).to_string())
-    })
-}
-
 impl FromRow<'_, sqlx::mysql::MySqlRow> for DatabaseUser {
     fn from_row(row: &sqlx::mysql::MySqlRow) -> Result<Self, sqlx::Error> {
         Ok(Self {