WIP

Cargo.lock

@@ -353,6 +353,16 @@ version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
+[[package]]
+name = "clap_mangen"
+version = "0.2.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "439ea63a92086df93893164221ad4f24142086d535b3a0957b9b9bea2dc86301"
+dependencies = [
+ "clap",
+ "roff",
+]
+
 [[package]]
 name = "color-print"
 version = "0.3.7"
@@ -695,7 +705,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -1127,7 +1137,7 @@ checksum = "3640c1c38b8e4e43584d8df18be5fc6b0aa314ce6ebf51b53313d4306cca8e46"
 dependencies = [
  "hermit-abi",
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -1337,6 +1347,7 @@ dependencies = [
  "clap",
  "clap-verbosity-flag",
  "clap_complete",
+ "clap_mangen",
  "color-print",
  "const_format",
  "derive_more",
@@ -1769,6 +1780,12 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "roff"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88f8660c1ff60292143c98d08fc6e2f654d722db50410e3f3797d40baaf9d8f3"
+
 [[package]]
 name = "rsa"
 version = "0.9.9"
@@ -1808,7 +1825,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -1914,16 +1931,16 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.146"
+version = "1.0.148"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "217ca874ae0207aac254aa02c957ded05585a90892cc8d87f9e5fa49669dadd8"
+checksum = "3084b546a1dd6289475996f182a22aba973866ea8e8b02c51d9f46b1336a22da"
 dependencies = [
  "indexmap",
  "itoa",
  "memchr",
- "ryu",
  "serde",
  "serde_core",
+ "zmij",
 ]
 
 [[package]]
@@ -2304,7 +2321,7 @@ dependencies = [
  "getrandom 0.3.4",
  "once_cell",
  "rustix",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -3219,6 +3236,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "zmij"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0f4a4e8e9dc5c62d159f04fcdbe07f4c3fb710415aab4754bf11505501e3251d"
+
 [[package]]
 name = "zstd"
 version = "0.13.3"

Cargo.toml

@@ -25,6 +25,7 @@ bincode = "2.0.1"
 clap = { version = "4.5.53", features = ["cargo", "derive"] }
 clap-verbosity-flag = { version = "3.0.4", features = [ "tracing" ] }
 clap_complete = { version = "4.5.62", features = ["unstable-dynamic"] }
+clap_mangen = "0.2.31"
 color-print = "0.3.7"
 const_format = "0.2.35"
 derive_more = { version = "2.1.1", features = ["display", "error"] }
@@ -38,7 +39,7 @@ num_cpus = "1.17.0"
 prettytable = "0.10.0"
 rand = "0.9.2"
 serde = "1.0.228"
-serde_json = { version = "1.0.146", features = ["preserve_order"] }
+serde_json = { version = "1.0.148", features = ["preserve_order"] }
 sqlx = { version = "0.8.6", features = ["runtime-tokio", "mysql", "tls-rustls"] }
 thiserror = "2.0.17"
 tokio = { version = "1.48.0", features = ["rt-multi-thread", "macros", "signal"] }
@@ -76,12 +77,12 @@ path = "src/lib.rs"
 [[bin]]
 name = "muscl"
 bench = false
-path = "src/entrypoints/muscl.rs"
+path = "src/bin/muscl.rs"
 
 [[bin]]
 name = "muscl-server"
 bench = false
-path = "src/entrypoints/muscl_server.rs"
+path = "src/bin/muscl_server.rs"
 
 [profile.release-lto]
 inherits = "release"

README.md

@@ -7,7 +7,7 @@ Dropping DBs (dumbbells) and having MySQL spasms since 2024
 
 ## What is this?
 
-`muscl is a secure MySQL administration tool for multi-user systems.
+`muscl` is a secure MySQL administration tool for multi-user systems.
 It allows unprivileged users to manage their own databases and database users without granting them direct access to the MySQL server.
 Authorization is handled by a prefix-based model tied to Unix users and groups, making it ideal for shared hosting environments, like university servers, tilde servers, or similar.
 
@@ -53,3 +53,12 @@ over a IPC, which then performs the requested operations on behalf of the client
 - [Compatibility mode with mysql-admutils](docs/mysql-admutils-compatibility.md)
 - [Use with NixOS](docs/nixos.md)
 - [SUID/SGID mode](docs/suid-sgid-mode.md)
+
+## History
+
+This is a rewrite of an older piece of software called [mysql-admutils](https://git.pvv.ntnu.no/Projects/mysql-admutils).
+Programvareverkstedet used this a lot back in the day, and it was great.
+But it had some security issues inherent to the software design, particularly related to the use of SUID/SGID.
+We tried patching it multiple times, but the issue kept popping up again in different ways.
+The rewrite was intended to iron this issue out completely by splitting the software into two pieces - a client and a server.
+As far as we know, this was successful, and it is unlikely for similar issues to resurface in the future.

assets/debian/group_denylist.txt

@@ -1,6 +1,7 @@
 # These are the default system groups on debian.
 # You can alos add groups by gid by prefixing the line with 'gid:'.
 
+group:_ssh
 group:adm
 group:audio
 group:avahi
@@ -12,6 +13,7 @@ group:daemon
 group:dialout
 group:dip
 group:disk
+group:docker
 group:fax
 group:floppy
 group:games
@@ -22,9 +24,12 @@ group:kmem
 group:kvm
 group:list
 group:lp
+group:lxd
 group:mail
 group:man
+group:messagebus
 group:mlocate
+group:mysql
 group:netdev
 group:news
 group:nogroup
@@ -42,15 +47,18 @@ group:src
 group:staff
 group:sudo
 group:sys
+group:syslog
 group:systemd-journal
 group:systemd-network
 group:systemd-resolve
 group:systemd-timesync
 group:tape
+group:tcpdump
 group:tty
 group:users
 group:utmp
 group:uucp
+group:uuidd
 group:video
 group:voice
 group:www-data

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "crane": {
       "locked": {
-        "lastModified": 1766194365,
-        "narHash": "sha256-4AFsUZ0kl6MXSm4BaQgItD0VGlEKR3iq7gIaL7TjBvc=",
+        "lastModified": 1766774972,
+        "narHash": "sha256-8qxEFpj4dVmIuPn9j9z6NTbU+hrcGjBOvaxTzre5HmM=",
         "owner": "ipetkov",
         "repo": "crane",
-        "rev": "7d8ec2c71771937ab99790b45e6d9b93d15d9379",
+        "rev": "01bc1d404a51a0a07e9d8759cd50a7903e218c82",
         "type": "github"
       },
       "original": {
@@ -17,11 +17,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1766309749,
-        "narHash": "sha256-3xY8CZ4rSnQ0NqGhMKAy5vgC+2IVK0NoVEzDoOh4DA4=",
+        "lastModified": 1766902085,
+        "narHash": "sha256-coBu0ONtFzlwwVBzmjacUQwj3G+lybcZ1oeNSQkgC0M=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "a6531044f6d0bef691ea18d4d4ce44d0daa6e816",
+        "rev": "c0b0e0fddf73fd517c3471e546c0df87a42d53f4",
         "type": "github"
       },
       "original": {
@@ -45,11 +45,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1766457837,
-        "narHash": "sha256-aeBbkQ0HPFNOIsUeEsXmZHXbYq4bG8ipT9JRlCcKHgU=",
+        "lastModified": 1766976750,
+        "narHash": "sha256-w+o3AIBI56tzfMJRqRXg9tSXnpQRN5hAT15o2t9rxYw=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "2c7510a559416d07242621d036847152d970612b",
+        "rev": "9fe44e7f05b734a64a01f92fc51ad064fb0a884f",
         "type": "github"
       },
       "original": {

nix/module.nix

@@ -42,9 +42,9 @@ in
 
           authorization = {
              group_denylist = lib.mkOption {
-               type = with lib.types; nullOr (listOf str);
+               type = with lib.types; nullOr (listOf (either str ints.unsigned));
                default = [ "wheel" ];
-               description = "List of groups that are denied access";
+               description = "List of groups/GIDs that can not be used as prefixes for databases/database users";
              };
           };
 
@@ -110,7 +110,32 @@ in
     ];
 
     environment.etc."muscl/group-denylist" = lib.mkIf (cfg.settings.authorization.group_denylist != [ ]) {
-      text = lib.concatMapStringsSep "\n" (group: "group:${group}") cfg.settings.authorization.group_denylist;
+      text = let
+        nameToGidMapping = lib.pipe config.users.groups [
+          (lib.filterAttrs (_: group: group.gid != null))
+          (lib.mapAttrsToList (name: group: { name = name; value = group.gid; }))
+          lib.listToAttrs
+        ];
+
+        gidToNameMapping = lib.pipe config.users.groups [
+          (lib.filterAttrs (_: group: group.gid != null))
+          (lib.mapAttrsToList (name: group: { name = toString group.gid; value = name; }))
+          lib.listToAttrs
+        ];
+      in lib.pipe cfg.settings.authorization.group_denylist [
+        # Prefer GIDs for groups we know the GID
+        (map (group: if builtins.isString group
+          then (nameToGidMapping.${group} or group)
+          else group))
+
+        # Then render back to strings
+        (map (group:
+           if builtins.isString group
+             then "group:${group}"
+             else "gid:${toString group} # ${gidToNameMapping.${toString group} or "unknown"}"))
+
+        (lib.concatStringsSep "\n")
+      ];
     };
 
     services.mysql.ensureUsers = lib.mkIf cfg.createLocalDatabaseUser [

src/bin/muscl.rs

@@ -82,9 +82,11 @@ const EXAMPLES: &str = const_format::concatcp!(
 
   # Show all databases
   muscl show-db
+  muscl sd
 
   # Show which users have privileges on which databases
   muscl show-privs
+  muscl sp
 "#,
 );
 
@@ -169,22 +171,27 @@ const EDIT_PRIVS_EXAMPLES: &str = color_print::cstr!(
 #[command(subcommand_required = true)]
 pub enum ClientCommand {
     /// Check whether you are authorized to manage the specified databases or users.
+    #[command(alias = "ca")]
     CheckAuth(CheckAuthArgs),
 
     /// Create one or more databases
+    #[command(alias = "cd")]
     CreateDb(CreateDbArgs),
 
     /// Delete one or more databases
+    #[command(alias = "dd")]
     DropDb(DropDbArgs),
 
     /// Print information about one or more databases
     ///
     /// If no database name is provided, all databases you have access will be shown.
+    #[command(alias = "sd")]
     ShowDb(ShowDbArgs),
 
     /// Print user privileges for one or more databases
     ///
     /// If no database names are provided, all databases you have access to will be shown.
+    #[command(alias = "sp")]
     ShowPrivs(ShowPrivsArgs),
 
     /// Change user privileges for one or more databases. See `edit-privs --help` for details.
@@ -239,27 +246,34 @@ pub enum ClientCommand {
         verbatim_doc_comment,
         override_usage = "muscl edit-privs [OPTIONS] [ -p <DB_NAME:USER_NAME:[+-]PRIVILEGES>... | <DB_NAME> <USER_NAME> <[+-]PRIVILEGES> ]",
         after_long_help = EDIT_PRIVS_EXAMPLES,
+        alias = "ep",
     )]
     EditPrivs(EditPrivsArgs),
 
     /// Create one or more users
+    #[command(alias = "cu")]
     CreateUser(CreateUserArgs),
 
     /// Delete one or more users
+    #[command(alias = "du")]
     DropUser(DropUserArgs),
 
     /// Change the MySQL password for a user
+    #[command(alias = "pu")]
     PasswdUser(PasswdUserArgs),
 
     /// Print information about one or more users
     ///
     /// If no username is provided, all users you have access will be shown.
+    #[command(alias = "su")]
     ShowUser(ShowUserArgs),
 
     /// Lock account for one or more users
+    #[command(alias = "lu")]
     LockUser(LockUserArgs),
 
     /// Unlock account for one or more users
+    #[command(alias = "uu")]
     UnlockUser(UnlockUserArgs),
 }
 
@@ -291,6 +305,10 @@ fn main() -> anyhow::Result<()> {
         return Ok(());
     }
 
+    if handle_manpage_command()?.is_some() {
+        return Ok(());
+    }
+
     #[cfg(feature = "mysql-admutils-compatibility")]
     if handle_mysql_admutils_command()?.is_some() {
         return Ok(());
@@ -347,6 +365,48 @@ fn handle_dynamic_completion() -> anyhow::Result<Option<()>> {
     }
 }
 
+/// **WARNING:** This function may be run with elevated privileges.
+fn handle_manpage_command() -> anyhow::Result<Option<()>> {
+    let argv1: Option<String> = std::env::args().nth(1);
+
+    match argv1.as_deref() {
+        Some("generate-manpages") => {
+            #[cfg(feature = "suid-sgid-mode")]
+            if executing_in_suid_sgid_mode()? {
+                use muscl_lib::core::bootstrap::drop_privs;
+                drop_privs()?
+            }
+
+            let output_dir = std::env::args().nth(2).ok_or(anyhow::anyhow!(
+                "Output directory argument missing for manpage generation"
+            ))?;
+
+            let output_dir = PathBuf::from(&output_dir);
+            if !output_dir.is_dir() {
+                anyhow::bail!(
+                    "Output directory `{:?}` does not exist or is not a directory",
+                    output_dir,
+                );
+            }
+
+            let mut roff = clap_mangen::roff::Roff::new();
+            let man = clap_mangen::Man::new(Args::command());
+            man.render_title(&mut std::io::stdout())?;
+            man.render_name_section(&mut std::io::stdout())?;
+            man.render_synopsis_section(&mut std::io::stdout())?;
+            man.render_subcommands_section(&mut std::io::stdout())?;
+            man.render_options_section(&mut std::io::stdout())?;
+
+            roff.control("SH", ["VERSION"]);
+            roff.text([clap_mangen::roff::roman(AFTER_LONG_HELP)]);
+            roff.to_writer(&mut std::io::stdout())?;
+
+            Ok(Some(()))
+        }
+        _ => Ok(None),
+    }
+}
+
 /// **WARNING:** This function may be run with elevated privileges.
 fn handle_mysql_admutils_command() -> anyhow::Result<Option<()>> {
     let argv0 = std::env::args().next().and_then(|s| {

src/client/commands/create_user.rs

@@ -1,3 +1,5 @@
+use std::io::IsTerminal;
+
 use clap::Parser;
 use clap_complete::ArgValueCompleter;
 use dialoguer::Confirm;
@@ -78,6 +80,15 @@ pub async fn create_users(
             .filter_map(|(username, result)| result.as_ref().ok().map(|()| username))
             .collect::<Vec<_>>();
 
+        if !std::io::stdin().is_terminal()
+            && !args.no_password
+            && !successfully_created_users.is_empty()
+        {
+            anyhow::bail!(
+                "Cannot prompt for passwords in non-interactive mode. Use --no-password to skip setting passwords."
+            );
+        }
+
         for username in successfully_created_users {
             if !args.no_password
                 && Confirm::new()

src/client/commands/drop_db.rs

@@ -1,3 +1,5 @@
+use std::io::IsTerminal;
+
 use clap::Parser;
 use clap_complete::ArgValueCompleter;
 use dialoguer::Confirm;
@@ -41,6 +43,12 @@ pub async fn drop_databases(
         anyhow::bail!("No database names provided");
     }
 
+    if !std::io::stdin().is_terminal() && !args.yes {
+        anyhow::bail!(
+            "Cannot prompt for confirmation in non-interactive mode. Use --yes to automatically confirm."
+        );
+    }
+
     if !args.yes {
         let confirmation = Confirm::new()
             .with_prompt(format!(
@@ -53,7 +61,6 @@ pub async fn drop_databases(
             ))
             .interact()?;
 
-        //
         if !confirmation {
             // TODO: should we return with an error code here?
             println!("Aborting drop operation.");

src/client/commands/drop_user.rs

@@ -1,3 +1,5 @@
+use std::io::IsTerminal;
+
 use clap::Parser;
 use clap_complete::ArgValueCompleter;
 use dialoguer::Confirm;
@@ -41,6 +43,12 @@ pub async fn drop_users(
         anyhow::bail!("No usernames provided");
     }
 
+    if !std::io::stdin().is_terminal() && !args.yes {
+        anyhow::bail!(
+            "Cannot prompt for confirmation in non-interactive mode. Use --yes to automatically confirm."
+        );
+    }
+
     if !args.yes {
         let confirmation = Confirm::new()
             .with_prompt(format!(

src/client/commands/edit_privs.rs

@@ -1,4 +1,7 @@
-use std::collections::{BTreeMap, BTreeSet};
+use std::{
+    collections::{BTreeMap, BTreeSet},
+    io::IsTerminal,
+};
 
 use anyhow::Context;
 use clap::{Args, Parser};
@@ -213,6 +216,11 @@ pub async fn edit_database_privileges(
     };
 
     let diffs: BTreeSet<DatabasePrivilegesDiff> = if privs.is_empty() {
+        if !std::io::stdin().is_terminal() {
+            anyhow::bail!(
+                "Cannot launch editor in non-interactive mode. Please provide privileges via command line arguments."
+            );
+        }
         let privileges_to_change =
             edit_privileges_with_editor(&existing_privilege_rows, use_database.as_ref())?;
         diff_privileges(&existing_privilege_rows, &privileges_to_change)
@@ -275,7 +283,8 @@ pub async fn edit_database_privileges(
     println!("The following changes will be made:\n");
     println!("{}", display_privilege_diffs(&diffs));
 
-    if !args.yes
+    if std::io::stdin().is_terminal()
+        && !args.yes
         && !Confirm::new()
             .with_prompt("Do you want to apply these changes?")
             .default(false)

src/client/commands/passwd_user.rs

@@ -1,4 +1,4 @@
-use std::path::PathBuf;
+use std::{io::IsTerminal, path::PathBuf};
 
 use anyhow::Context;
 use clap::Parser;
@@ -88,6 +88,11 @@ pub async fn passwd_user(
             .context("Failed to read password from stdin")?;
         buffer.trim().to_string()
     } else {
+        if !std::io::stdin().is_terminal() {
+            anyhow::bail!(
+                "Cannot prompt for password in non-interactive mode. Use --stdin or --password-file to provide the password."
+            );
+        }
         read_password_from_stdin_with_double_check(&args.username)?
     };
 

src/core/bootstrap.rs

@@ -22,7 +22,7 @@ use crate::{
         authorization::read_and_parse_group_denylist,
         config::{MysqlConfig, ServerConfig},
         landlock::landlock_restrict_server,
-        session_handler,
+        session_handler::{self, SessionId},
     },
 };
 
@@ -308,9 +308,11 @@ fn run_forked_server(
                 version_row.to_lowercase().contains("mariadb")
             };
 
+            let session_id = SessionId::new(0);
             let db_pool = Arc::new(RwLock::new(db_pool));
             session_handler::session_handler_with_unix_user(
                 socket,
+                session_id,
                 unix_user,
                 db_pool,
                 db_is_mariadb,

src/core/common.rs

@@ -24,6 +24,7 @@ pub const KIND_REGARDS: &str = concat!(
     "If you experience any bugs or turbulence, please give us a heads up :)",
 );
 
+/// TODO: store and display UID
 #[derive(Debug, Clone)]
 pub struct UnixUser {
     pub username: String,

src/core/protocol/commands.rs

@@ -36,11 +36,16 @@ pub use modify_privileges::*;
 pub use passwd_user::*;
 pub use unlock_users::*;
 
+use std::collections::BTreeSet;
+use std::fmt;
+
 use serde::{Deserialize, Serialize};
 use tokio::net::UnixStream;
 use tokio_serde::{Framed as SerdeFramed, formats::Bincode};
 use tokio_util::codec::{Framed, LengthDelimitedCodec};
 
+use crate::core::types::{MySQLDatabase, MySQLUser};
+
 pub type ServerToClientMessageStream = SerdeFramed<
     Framed<UnixStream, LengthDelimitedCodec>,
     Request,
@@ -104,6 +109,124 @@ pub enum Request {
     Exit,
 }
 
+impl Request {
+    /// Get the command name associated with this request.
+    pub fn command_name(&self) -> &str {
+        match self {
+            Request::CheckAuthorization(_) => "check-authorization",
+            Request::ListValidNamePrefixes => "list-valid-name-prefixes",
+            Request::CompleteDatabaseName(_) => "complete-database-name",
+            Request::CompleteUserName(_) => "complete-user-name",
+            Request::CreateDatabases(_) => "create-databases",
+            Request::DropDatabases(_) => "drop-databases",
+            Request::ListDatabases(_) => "list-databases",
+            Request::ListPrivileges(_) => "list-privileges",
+            Request::ModifyPrivileges(_) => "modify-privileges",
+            Request::CreateUsers(_) => "create-users",
+            Request::DropUsers(_) => "drop-users",
+            Request::PasswdUser(_) => "passwd-user",
+            Request::ListUsers(_) => "list-users",
+            Request::LockUsers(_) => "lock-users",
+            Request::UnlockUsers(_) => "unlock-users",
+            Request::Exit => "exit",
+        }
+    }
+
+    /// Generate a short summary string representing this request for logging purposes.
+    pub fn log_summary(&self) -> String {
+        match self {
+            Request::CheckAuthorization(req) => format!("{}({})", self.command_name(), req.len()),
+
+            Request::CreateDatabases(req) => format!("{}({})", self.command_name(), req.len()),
+            Request::DropDatabases(req) => format!("{}({})", self.command_name(), req.len()),
+            Request::ListDatabases(req) => format!(
+                "{}{}",
+                self.command_name(),
+                req.as_ref()
+                    .map_or("".to_string(), |r| format!("({})", r.len()))
+            ),
+            Request::ListPrivileges(req) => format!(
+                "{}{}",
+                self.command_name(),
+                req.as_ref()
+                    .map_or("".to_string(), |r| format!("({})", r.len()))
+            ),
+            Request::ModifyPrivileges(req) => format!("{}({})", self.command_name(), req.len()),
+
+            Request::CreateUsers(req) => format!("{}({})", self.command_name(), req.len()),
+            Request::DropUsers(req) => format!("{}({})", self.command_name(), req.len()),
+            Request::ListUsers(req) => format!(
+                "{}{}",
+                self.command_name(),
+                req.as_ref()
+                    .map_or("".to_string(), |r| format!("({})", r.len()))
+            ),
+            Request::LockUsers(req) => format!("{}({})", self.command_name(), req.len()),
+            Request::UnlockUsers(req) => format!("{}({})", self.command_name(), req.len()),
+
+            _ => self.command_name().to_string(),
+        }
+    }
+
+    /// Get the set of users affected by this request.
+    pub fn affected_users(&self) -> BTreeSet<MySQLUser> {
+        match self {
+            Request::CheckAuthorization(_) => Default::default(),
+            Request::ListValidNamePrefixes => Default::default(),
+            Request::CompleteDatabaseName(_) => Default::default(),
+            Request::CompleteUserName(_) => Default::default(),
+            Request::CreateDatabases(_) => Default::default(),
+            Request::DropDatabases(_) => Default::default(),
+            Request::ListDatabases(_) => Default::default(),
+            Request::ListPrivileges(_) => Default::default(),
+            Request::ModifyPrivileges(priv_diffs) => priv_diffs
+                .iter()
+                .map(|priv_diff| priv_diff.get_user_name().clone())
+                .collect(),
+            Request::CreateUsers(users) => users.iter().cloned().collect(),
+            Request::DropUsers(users) => users.iter().cloned().collect(),
+            Request::PasswdUser(user_passwd_req) => {
+                let mut result = BTreeSet::new();
+                result.insert(user_passwd_req.0.clone());
+                result
+            }
+            Request::ListUsers(users) => users.clone().unwrap_or_default().into_iter().collect(),
+            Request::LockUsers(users) => users.iter().cloned().collect(),
+            Request::UnlockUsers(users) => users.iter().cloned().collect(),
+            Request::Exit => Default::default(),
+        }
+    }
+
+    /// Get the set of databases affected by this request.
+    pub fn affected_databases(&self) -> BTreeSet<MySQLDatabase> {
+        match self {
+            Request::CheckAuthorization(_) => Default::default(),
+            Request::ListValidNamePrefixes => Default::default(),
+            Request::CompleteDatabaseName(_) => Default::default(),
+            Request::CompleteUserName(_) => Default::default(),
+            Request::CreateDatabases(databases) => databases.iter().cloned().collect(),
+            Request::DropDatabases(databases) => databases.iter().cloned().collect(),
+            Request::ListDatabases(databases) => {
+                databases.clone().unwrap_or_default().into_iter().collect()
+            }
+            Request::ListPrivileges(databases) => {
+                databases.clone().unwrap_or_default().into_iter().collect()
+            }
+            Request::ModifyPrivileges(priv_diffs) => priv_diffs
+                .iter()
+                .map(|priv_diff| priv_diff.get_database_name().clone())
+                .collect(),
+            Request::CreateUsers(_) => Default::default(),
+            Request::DropUsers(_) => Default::default(),
+            Request::PasswdUser(_) => Default::default(),
+            Request::ListUsers(_) => Default::default(),
+            Request::LockUsers(_) => Default::default(),
+            Request::UnlockUsers(_) => Default::default(),
+            Request::Exit => Default::default(),
+        }
+    }
+}
+
 // TODO: include a generic "message" that will display a message to the user?
 
 #[non_exhaustive]
@@ -136,3 +259,95 @@ pub enum Response {
     Ready,
     Error(String),
 }
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub enum ResponseOkStatus {
+    Success,
+    PartialSuccess(usize, usize), // succeeded, total
+    Error,
+}
+
+impl ResponseOkStatus {
+    pub fn from_counts(total: usize, succeeded: usize) -> Self {
+        if succeeded == total {
+            ResponseOkStatus::Success
+        } else if succeeded == 0 {
+            ResponseOkStatus::Error
+        } else {
+            ResponseOkStatus::PartialSuccess(succeeded, total)
+        }
+    }
+
+    pub fn from_bool(is_ok: bool) -> Self {
+        if is_ok {
+            ResponseOkStatus::Success
+        } else {
+            ResponseOkStatus::Error
+        }
+    }
+}
+
+impl fmt::Display for ResponseOkStatus {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ResponseOkStatus::Success => write!(f, "OK"),
+            ResponseOkStatus::PartialSuccess(succeeded, total) => {
+                write!(f, "PARTIAL_OK({}/{})", succeeded, total)
+            }
+            ResponseOkStatus::Error => write!(f, "ERR"),
+        }
+    }
+}
+
+impl Response {
+    pub fn ok_status(&self) -> ResponseOkStatus {
+        match self {
+            Response::CheckAuthorization(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+
+            Response::ListValidNamePrefixes(_) => ResponseOkStatus::Success,
+            Response::CompleteDatabaseName(_) => ResponseOkStatus::Success,
+            Response::CompleteUserName(_) => ResponseOkStatus::Success,
+
+            Response::CreateDatabases(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+            Response::DropDatabases(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+            Response::ListDatabases(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+            Response::ListAllDatabases(res) => ResponseOkStatus::from_bool(res.is_ok()),
+            Response::ListPrivileges(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+            Response::ListAllPrivileges(res) => ResponseOkStatus::from_bool(res.is_ok()),
+            Response::ModifyPrivileges(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+
+            Response::CreateUsers(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+            Response::DropUsers(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+            Response::SetUserPassword(res) => ResponseOkStatus::from_bool(res.is_ok()),
+            Response::ListUsers(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+            Response::ListAllUsers(res) => ResponseOkStatus::from_bool(res.is_ok()),
+            Response::LockUsers(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+            Response::UnlockUsers(res) => {
+                ResponseOkStatus::from_counts(res.len(), res.values().filter(|v| v.is_ok()).count())
+            }
+
+            Response::Ready => ResponseOkStatus::Success,
+            Response::Error(_) => ResponseOkStatus::Error,
+        }
+    }
+}

src/server/authorization.rs

@@ -1,4 +1,4 @@
-use std::{collections::HashSet, path::Path};
+use std::{collections::HashSet, path::Path, str::Lines};
 
 use anyhow::Context;
 use nix::unistd::Group;
@@ -13,23 +13,19 @@ use crate::core::{
 };
 
 pub async fn check_authorization(
-    dbs_or_users: Vec<DbOrUser>,
+    dbs_or_users: &[DbOrUser],
     unix_user: &UnixUser,
     group_denylist: &GroupDenylist,
 ) -> std::collections::BTreeMap<DbOrUser, Result<(), CheckAuthorizationError>> {
-    let mut results = std::collections::BTreeMap::new();
-
-    for db_or_user in dbs_or_users {
-        if let Err(err) = validate_db_or_user_request(&db_or_user, unix_user, group_denylist)
-            .map_err(CheckAuthorizationError)
-        {
-            results.insert(db_or_user.clone(), Err(err));
-            continue;
-        }
-        results.insert(db_or_user.clone(), Ok(()));
-    }
-
-    results
+    dbs_or_users
+        .iter()
+        .cloned()
+        .map(|db_or_user| {
+            let result = validate_db_or_user_request(&db_or_user, unix_user, group_denylist)
+                .map_err(CheckAuthorizationError);
+            (db_or_user, result)
+        })
+        .collect()
 }
 
 /// Reads and parses a group denylist file, returning a set of GUIDs
@@ -45,14 +41,23 @@ pub fn read_and_parse_group_denylist(denylist_path: &Path) -> anyhow::Result<Gro
     let content = std::fs::read_to_string(denylist_path)
         .context(format!("Failed to read denylist file at {denylist_path:?}"))?;
 
-    let mut groups = HashSet::with_capacity(content.lines().count());
+    let lines = content.lines();
 
-    for (line_number, line) in content.lines().enumerate() {
-        let trimmed_line = line.trim();
+    let groups = parse_group_denylist(denylist_path, lines);
 
-        if trimmed_line.is_empty() || trimmed_line.starts_with('#') {
-            continue;
+    Ok(groups)
+}
+
+fn parse_group_denylist(denylist_path: &Path, lines: Lines) -> GroupDenylist {
+    let mut groups = HashSet::<u32>::new();
+
+    for (line_number, line) in lines.enumerate() {
+        let trimmed_line = if let Some(comment_start) = line.find('#') {
+            &line[..comment_start]
+        } else {
+            line
         }
+        .trim();
 
         let parts: Vec<&str> = trimmed_line.splitn(2, ':').collect();
         if parts.len() != 2 {
@@ -141,5 +146,32 @@ pub fn read_and_parse_group_denylist(denylist_path: &Path) -> anyhow::Result<Gro
         }
     }
 
-    Ok(groups)
+    groups
+}
+
+#[cfg(test)]
+mod tests {
+    use indoc::indoc;
+
+    use super::*;
+
+    #[test]
+    fn test_parse_group_denylist() {
+        let denylist_content = indoc! {"
+            # Valid entries
+            gid:0 # This is usually the 'root' group
+            group:root # This is also the 'root' group, should deduplicate
+
+            # Invalid entries
+            invalid_line
+            gid:not_a_number
+            group:nonexistent_group
+        "};
+
+        let lines = denylist_content.lines();
+        let group_denylist = parse_group_denylist(Path::new("test_denylist"), lines);
+
+        assert_eq!(group_denylist.len(), 1);
+        assert!(group_denylist.contains(&0));
+    }
 }

src/server/session_handler.rs

@@ -1,7 +1,8 @@
-use std::{collections::BTreeSet, sync::Arc};
+use std::sync::Arc;
 
 use futures_util::{SinkExt, StreamExt};
 use indoc::concatdoc;
+use itertools::Itertools;
 use sqlx::{MySqlConnection, MySqlPool};
 use tokio::{net::UnixStream, sync::RwLock};
 use tracing::Instrument;
@@ -34,10 +35,24 @@ use crate::{
     },
 };
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct SessionId(u64);
+
+impl SessionId {
+    pub fn new(id: u64) -> Self {
+        SessionId(id)
+    }
+
+    pub fn inner(&self) -> u64 {
+        self.0
+    }
+}
+
 // TODO: don't use database connection unless necessary.
 
 pub async fn session_handler(
     socket: UnixStream,
+    session_id: SessionId,
     db_pool: Arc<RwLock<MySqlPool>>,
     db_is_mariadb: bool,
     group_denylist: &GroupDenylist,
@@ -61,7 +76,7 @@ pub async fn session_handler(
         }
     };
 
-    tracing::debug!("Validated peer UID: {}", uid);
+    tracing::trace!("Validated peer UID: {}", uid);
 
     let unix_user = match UnixUser::from_uid(uid) {
         Ok(user) => user,
@@ -82,13 +97,18 @@ pub async fn session_handler(
         }
     };
 
-    let span = tracing::info_span!("user_session", user = %unix_user);
+    let span = tracing::info_span!(
+        "user_session",
+        session_id = session_id.inner(),
+        user = %unix_user,
+    );
 
     (async move {
-        tracing::info!("Accepted connection from user: {}", unix_user);
+        tracing::debug!("Accepted connection from user: {}", unix_user);
 
         let result = session_handler_with_unix_user(
             socket,
+            session_id,
             &unix_user,
             db_pool,
             db_is_mariadb,
@@ -96,7 +116,7 @@ pub async fn session_handler(
         )
         .await;
 
-        tracing::info!(
+        tracing::debug!(
             "Finished handling requests for connection from user: {}",
             unix_user,
         );
@@ -109,6 +129,7 @@ pub async fn session_handler(
 
 pub async fn session_handler_with_unix_user(
     socket: UnixStream,
+    session_id: SessionId,
     unix_user: &UnixUser,
     db_pool: Arc<RwLock<MySqlPool>>,
     db_is_mariadb: bool,
@@ -116,7 +137,7 @@ pub async fn session_handler_with_unix_user(
 ) -> anyhow::Result<()> {
     let mut message_stream = create_server_to_client_message_stream(socket);
 
-    tracing::debug!("Requesting database connection from pool");
+    tracing::trace!("Requesting database connection from pool");
     let mut db_connection = match db_pool.read().await.acquire().await {
         Ok(connection) => connection,
         Err(err) => {
@@ -133,10 +154,11 @@ pub async fn session_handler_with_unix_user(
             return Err(err.into());
         }
     };
-    tracing::debug!("Successfully acquired database connection from pool");
+    tracing::trace!("Successfully acquired database connection from pool");
 
     let result = session_handler_with_db_connection(
         message_stream,
+        session_id,
         unix_user,
         &mut db_connection,
         db_is_mariadb,
@@ -144,7 +166,7 @@ pub async fn session_handler_with_unix_user(
     )
     .await;
 
-    tracing::debug!("Releasing database connection back to pool");
+    tracing::trace!("Releasing database connection back to pool");
 
     result
 }
@@ -154,6 +176,7 @@ pub async fn session_handler_with_unix_user(
 
 async fn session_handler_with_db_connection(
     mut stream: ServerToClientMessageStream,
+    session_id: SessionId,
     unix_user: &UnixUser,
     db_connection: &mut MySqlConnection,
     db_is_mariadb: bool,
@@ -173,247 +196,311 @@ async fn session_handler_with_db_connection(
             }
         };
 
-        // TODO: don't clone the request
-        let request_to_display = match &request {
-            Request::PasswdUser((db_user, _)) => {
-                Request::PasswdUser((db_user.to_owned(), "<REDACTED>".to_string()))
-            }
-            request => request.to_owned(),
-        };
+        let request_span = tracing::info_span!("request", command = request.command_name());
 
-        if request_to_display == Request::Exit {
-            tracing::debug!("Received request: {:#?}", request_to_display);
-        } else {
-            tracing::info!("Received request: {:#?}", request_to_display);
+        if !handle_request(
+            request,
+            session_id,
+            unix_user,
+            db_connection,
+            db_is_mariadb,
+            group_denylist,
+            &mut stream,
+        )
+        .instrument(request_span)
+        .await?
+        {
+            break;
         }
-
-        let response = match request {
-            Request::CheckAuthorization(dbs_or_users) => {
-                let result = check_authorization(dbs_or_users, unix_user, group_denylist).await;
-                Response::CheckAuthorization(result)
-            }
-            Request::ListValidNamePrefixes => {
-                let mut result = Vec::with_capacity(unix_user.groups.len() + 1);
-                result.push(unix_user.username.clone());
-
-                for group in get_user_filtered_groups(unix_user, group_denylist) {
-                    result.push(group.clone());
-                }
-
-                Response::ListValidNamePrefixes(result)
-            }
-            Request::CompleteDatabaseName(partial_database_name) => {
-                // TODO: more correct validation here
-                if partial_database_name
-                    .chars()
-                    .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-')
-                {
-                    let result = complete_database_name(
-                        partial_database_name,
-                        unix_user,
-                        db_connection,
-                        db_is_mariadb,
-                        group_denylist,
-                    )
-                    .await;
-                    Response::CompleteDatabaseName(result)
-                } else {
-                    Response::CompleteDatabaseName(vec![])
-                }
-            }
-            Request::CompleteUserName(partial_user_name) => {
-                // TODO: more correct validation here
-                if partial_user_name
-                    .chars()
-                    .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-')
-                {
-                    let result = complete_user_name(
-                        partial_user_name,
-                        unix_user,
-                        db_connection,
-                        db_is_mariadb,
-                        group_denylist,
-                    )
-                    .await;
-                    Response::CompleteUserName(result)
-                } else {
-                    Response::CompleteUserName(vec![])
-                }
-            }
-            Request::CreateDatabases(databases_names) => {
-                let result = create_databases(
-                    databases_names,
-                    unix_user,
-                    db_connection,
-                    db_is_mariadb,
-                    group_denylist,
-                )
-                .await;
-                Response::CreateDatabases(result)
-            }
-            Request::DropDatabases(databases_names) => {
-                let result = drop_databases(
-                    databases_names,
-                    unix_user,
-                    db_connection,
-                    db_is_mariadb,
-                    group_denylist,
-                )
-                .await;
-                Response::DropDatabases(result)
-            }
-            Request::ListDatabases(database_names) => {
-                if let Some(database_names) = database_names {
-                    let result = list_databases(
-                        database_names,
-                        unix_user,
-                        db_connection,
-                        db_is_mariadb,
-                        group_denylist,
-                    )
-                    .await;
-                    Response::ListDatabases(result)
-                } else {
-                    let result = list_all_databases_for_user(
-                        unix_user,
-                        db_connection,
-                        db_is_mariadb,
-                        group_denylist,
-                    )
-                    .await;
-                    Response::ListAllDatabases(result)
-                }
-            }
-            Request::ListPrivileges(database_names) => {
-                if let Some(database_names) = database_names {
-                    let privilege_data = get_databases_privilege_data(
-                        database_names,
-                        unix_user,
-                        db_connection,
-                        db_is_mariadb,
-                        group_denylist,
-                    )
-                    .await;
-                    Response::ListPrivileges(privilege_data)
-                } else {
-                    let privilege_data = get_all_database_privileges(
-                        unix_user,
-                        db_connection,
-                        db_is_mariadb,
-                        group_denylist,
-                    )
-                    .await;
-                    Response::ListAllPrivileges(privilege_data)
-                }
-            }
-            Request::ModifyPrivileges(database_privilege_diffs) => {
-                let result = apply_privilege_diffs(
-                    BTreeSet::from_iter(database_privilege_diffs),
-                    unix_user,
-                    db_connection,
-                    db_is_mariadb,
-                    group_denylist,
-                )
-                .await;
-                Response::ModifyPrivileges(result)
-            }
-            Request::CreateUsers(db_users) => {
-                let result = create_database_users(
-                    db_users,
-                    unix_user,
-                    db_connection,
-                    db_is_mariadb,
-                    group_denylist,
-                )
-                .await;
-                Response::CreateUsers(result)
-            }
-            Request::DropUsers(db_users) => {
-                let result = drop_database_users(
-                    db_users,
-                    unix_user,
-                    db_connection,
-                    db_is_mariadb,
-                    group_denylist,
-                )
-                .await;
-                Response::DropUsers(result)
-            }
-            Request::PasswdUser((db_user, password)) => {
-                let result = set_password_for_database_user(
-                    &db_user,
-                    &password,
-                    unix_user,
-                    db_connection,
-                    db_is_mariadb,
-                    group_denylist,
-                )
-                .await;
-                Response::SetUserPassword(result)
-            }
-            Request::ListUsers(db_users) => {
-                if let Some(db_users) = db_users {
-                    let result = list_database_users(
-                        db_users,
-                        unix_user,
-                        db_connection,
-                        db_is_mariadb,
-                        group_denylist,
-                    )
-                    .await;
-                    Response::ListUsers(result)
-                } else {
-                    let result = list_all_database_users_for_unix_user(
-                        unix_user,
-                        db_connection,
-                        db_is_mariadb,
-                        group_denylist,
-                    )
-                    .await;
-                    Response::ListAllUsers(result)
-                }
-            }
-            Request::LockUsers(db_users) => {
-                let result = lock_database_users(
-                    db_users,
-                    unix_user,
-                    db_connection,
-                    db_is_mariadb,
-                    group_denylist,
-                )
-                .await;
-                Response::LockUsers(result)
-            }
-            Request::UnlockUsers(db_users) => {
-                let result = unlock_database_users(
-                    db_users,
-                    unix_user,
-                    db_connection,
-                    db_is_mariadb,
-                    group_denylist,
-                )
-                .await;
-                Response::UnlockUsers(result)
-            }
-            Request::Exit => {
-                break;
-            }
-        };
-
-        let response_to_display = match &response {
-            Response::SetUserPassword(Err(SetPasswordError::MySqlError(_))) => {
-                &Response::SetUserPassword(Err(SetPasswordError::MySqlError(
-                    "<REDACTED>".to_string(),
-                )))
-            }
-            response => response,
-        };
-        tracing::debug!("Response: {:#?}", response_to_display);
-
-        stream.send(response).await?;
-        stream.flush().await?;
-        tracing::debug!("Successfully processed request");
     }
 
     Ok(())
 }
+
+/// Handle a single request from a client.
+///
+/// If the function returns `true`, the session should continue.
+async fn handle_request(
+    request: Request,
+    session_id: SessionId,
+    unix_user: &UnixUser,
+    db_connection: &mut MySqlConnection,
+    db_is_mariadb: bool,
+    group_denylist: &GroupDenylist,
+    stream: &mut ServerToClientMessageStream,
+) -> anyhow::Result<bool> {
+    match &request {
+        Request::Exit => tracing::debug!("Request: exit"),
+        Request::PasswdUser((db_user, _)) => tracing::debug!(
+            "Request:\n{}",
+            serde_json::to_string_pretty(&Request::PasswdUser((
+                db_user.to_owned(),
+                "<REDACTED>".to_string()
+            )))?
+        ),
+        request => tracing::debug!("Request:\n{}", serde_json::to_string_pretty(request)?),
+    }
+
+    let affected_dbs = request.affected_databases();
+    if !affected_dbs.is_empty() {
+        tracing::trace!(
+            "Affected databases: {}",
+            affected_dbs.into_iter().map(|db| db.to_string()).join(", ")
+        );
+    }
+
+    let affected_users = request.affected_users();
+    if !affected_users.is_empty() {
+        tracing::trace!(
+            "Affected users: {}",
+            affected_users.into_iter().map(|u| u.to_string()).join(", "),
+        );
+    }
+
+    let response = match request {
+        Request::CheckAuthorization(ref dbs_or_users) => {
+            let result = check_authorization(dbs_or_users, unix_user, group_denylist).await;
+            Response::CheckAuthorization(result)
+        }
+        Request::ListValidNamePrefixes => {
+            let mut result = Vec::with_capacity(unix_user.groups.len() + 1);
+            result.push(unix_user.username.clone());
+
+            for group in get_user_filtered_groups(unix_user, group_denylist) {
+                result.push(group.clone());
+            }
+
+            Response::ListValidNamePrefixes(result)
+        }
+        Request::CompleteDatabaseName(ref partial_database_name) => {
+            // TODO: more correct validation here
+            if partial_database_name
+                .chars()
+                .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-')
+            {
+                let result = complete_database_name(
+                    partial_database_name,
+                    unix_user,
+                    db_connection,
+                    db_is_mariadb,
+                    group_denylist,
+                )
+                .await;
+                Response::CompleteDatabaseName(result)
+            } else {
+                Response::CompleteDatabaseName(vec![])
+            }
+        }
+        Request::CompleteUserName(ref partial_user_name) => {
+            // TODO: more correct validation here
+            if partial_user_name
+                .chars()
+                .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-')
+            {
+                let result = complete_user_name(
+                    partial_user_name,
+                    unix_user,
+                    db_connection,
+                    db_is_mariadb,
+                    group_denylist,
+                )
+                .await;
+                Response::CompleteUserName(result)
+            } else {
+                Response::CompleteUserName(vec![])
+            }
+        }
+        Request::CreateDatabases(ref databases_names) => {
+            let result = create_databases(
+                databases_names,
+                unix_user,
+                db_connection,
+                db_is_mariadb,
+                group_denylist,
+            )
+            .await;
+            Response::CreateDatabases(result)
+        }
+        Request::DropDatabases(ref databases_names) => {
+            let result = drop_databases(
+                databases_names,
+                unix_user,
+                db_connection,
+                db_is_mariadb,
+                group_denylist,
+            )
+            .await;
+            Response::DropDatabases(result)
+        }
+        Request::ListDatabases(ref database_names) => {
+            if let Some(database_names) = database_names {
+                let result = list_databases(
+                    database_names,
+                    unix_user,
+                    db_connection,
+                    db_is_mariadb,
+                    group_denylist,
+                )
+                .await;
+                Response::ListDatabases(result)
+            } else {
+                let result = list_all_databases_for_user(
+                    unix_user,
+                    db_connection,
+                    db_is_mariadb,
+                    group_denylist,
+                )
+                .await;
+                Response::ListAllDatabases(result)
+            }
+        }
+        Request::ListPrivileges(ref database_names) => {
+            if let Some(database_names) = database_names {
+                let privilege_data = get_databases_privilege_data(
+                    database_names,
+                    unix_user,
+                    db_connection,
+                    db_is_mariadb,
+                    group_denylist,
+                )
+                .await;
+                Response::ListPrivileges(privilege_data)
+            } else {
+                let privilege_data = get_all_database_privileges(
+                    unix_user,
+                    db_connection,
+                    db_is_mariadb,
+                    group_denylist,
+                )
+                .await;
+                Response::ListAllPrivileges(privilege_data)
+            }
+        }
+        Request::ModifyPrivileges(ref database_privilege_diffs) => {
+            let result = apply_privilege_diffs(
+                database_privilege_diffs,
+                unix_user,
+                db_connection,
+                db_is_mariadb,
+                group_denylist,
+            )
+            .await;
+            Response::ModifyPrivileges(result)
+        }
+        Request::CreateUsers(ref db_users) => {
+            let result = create_database_users(
+                db_users,
+                unix_user,
+                db_connection,
+                db_is_mariadb,
+                group_denylist,
+            )
+            .await;
+            Response::CreateUsers(result)
+        }
+        Request::DropUsers(ref db_users) => {
+            let result = drop_database_users(
+                db_users,
+                unix_user,
+                db_connection,
+                db_is_mariadb,
+                group_denylist,
+            )
+            .await;
+            Response::DropUsers(result)
+        }
+        Request::PasswdUser((ref db_user, ref password)) => {
+            let result = set_password_for_database_user(
+                db_user,
+                password,
+                unix_user,
+                db_connection,
+                db_is_mariadb,
+                group_denylist,
+            )
+            .await;
+            Response::SetUserPassword(result)
+        }
+        Request::ListUsers(ref db_users) => {
+            if let Some(db_users) = db_users {
+                let result = list_database_users(
+                    db_users,
+                    unix_user,
+                    db_connection,
+                    db_is_mariadb,
+                    group_denylist,
+                )
+                .await;
+                Response::ListUsers(result)
+            } else {
+                let result = list_all_database_users_for_unix_user(
+                    unix_user,
+                    db_connection,
+                    db_is_mariadb,
+                    group_denylist,
+                )
+                .await;
+                Response::ListAllUsers(result)
+            }
+        }
+        Request::LockUsers(ref db_users) => {
+            let result = lock_database_users(
+                db_users,
+                unix_user,
+                db_connection,
+                db_is_mariadb,
+                group_denylist,
+            )
+            .await;
+            Response::LockUsers(result)
+        }
+        Request::UnlockUsers(ref db_users) => {
+            let result = unlock_database_users(
+                db_users,
+                unix_user,
+                db_connection,
+                db_is_mariadb,
+                group_denylist,
+            )
+            .await;
+            Response::UnlockUsers(result)
+        }
+        Request::Exit => {
+            return Ok(false);
+        }
+    };
+
+    let response_to_display = match &response {
+        Response::SetUserPassword(Err(SetPasswordError::MySqlError(_))) => {
+            &Response::SetUserPassword(Err(SetPasswordError::MySqlError("<REDACTED>".to_string())))
+        }
+        response => response,
+    };
+    tracing::debug!(
+        "Response:\n{}",
+        serde_json::to_string_pretty(&response_to_display)?
+    );
+
+    log_request(session_id, unix_user, &request, &response);
+
+    stream.send(response).await?;
+    stream.flush().await?;
+    tracing::trace!("Successfully processed request");
+
+    Ok(true)
+}
+
+/// Log a summary of the request and its result.
+fn log_request(
+    session_id: SessionId,
+    unix_user: &UnixUser,
+    request: &Request,
+    response: &Response,
+) {
+    tracing::info!(
+        "[{}|session:{}|user:{unix_user}] {}",
+        response.ok_status(),
+        session_id.inner(),
+        request.log_summary(),
+    );
+}

src/server/sql/database_operations.rs

@@ -46,7 +46,7 @@ pub(super) async fn unsafe_database_exists(
 }
 
 pub async fn complete_database_name(
-    database_prefix: String,
+    database_prefix: &str,
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -87,7 +87,7 @@ pub async fn complete_database_name(
 }
 
 pub async fn create_databases(
-    database_names: Vec<MySQLDatabase>,
+    database_names: &[MySQLDatabase],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -95,7 +95,7 @@ pub async fn create_databases(
 ) -> CreateDatabasesResponse {
     let mut results = BTreeMap::new();
 
-    for database_name in database_names {
+    for database_name in database_names.iter().cloned() {
         if let Err(err) = validate_db_or_user_request(
             &DbOrUser::Database(database_name.clone()),
             unix_user,
@@ -143,7 +143,7 @@ pub async fn create_databases(
 }
 
 pub async fn drop_databases(
-    database_names: Vec<MySQLDatabase>,
+    database_names: &[MySQLDatabase],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -151,7 +151,7 @@ pub async fn drop_databases(
 ) -> DropDatabasesResponse {
     let mut results = BTreeMap::new();
 
-    for database_name in database_names {
+    for database_name in database_names.iter().cloned() {
         if let Err(err) = validate_db_or_user_request(
             &DbOrUser::Database(database_name.clone()),
             unix_user,
@@ -242,7 +242,7 @@ impl FromRow<'_, sqlx::mysql::MySqlRow> for DatabaseRow {
 }
 
 pub async fn list_databases(
-    database_names: Vec<MySQLDatabase>,
+    database_names: &[MySQLDatabase],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -250,7 +250,7 @@ pub async fn list_databases(
 ) -> ListDatabasesResponse {
     let mut results = BTreeMap::new();
 
-    for database_name in database_names {
+    for database_name in database_names.iter().cloned() {
         if let Err(err) = validate_db_or_user_request(
             &DbOrUser::Database(database_name.clone()),
             unix_user,

src/server/sql/database_privilege_operations.rs

@@ -138,7 +138,7 @@ pub async fn unsafe_get_database_privileges_for_db_user_pair(
 }
 
 pub async fn get_databases_privilege_data(
-    database_names: Vec<MySQLDatabase>,
+    database_names: &[MySQLDatabase],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -146,19 +146,19 @@ pub async fn get_databases_privilege_data(
 ) -> ListPrivilegesResponse {
     let mut results = BTreeMap::new();
 
-    for database_name in &database_names {
+    for database_name in database_names.iter().cloned() {
         if let Err(err) = validate_db_or_user_request(
-            &DbOrUser::Database(database_name.clone()),
+            &DbOrUser::Database(database_name.to_owned()),
             unix_user,
             group_denylist,
         )
         .map_err(ListPrivilegesError::ValidationError)
         {
-            results.insert(database_name.to_owned(), Err(err));
+            results.insert(database_name, Err(err));
             continue;
         }
 
-        match unsafe_database_exists(database_name, connection).await {
+        match unsafe_database_exists(&database_name, connection).await {
             Ok(false) => {
                 results.insert(
                     database_name.to_owned(),
@@ -176,7 +176,7 @@ pub async fn get_databases_privilege_data(
             Ok(true) => {}
         }
 
-        let result = unsafe_get_database_privileges(database_name, connection)
+        let result = unsafe_get_database_privileges(&database_name, connection)
             .await
             .map_err(|e| ListPrivilegesError::MySqlError(e.to_string()));
 
@@ -400,7 +400,7 @@ async fn validate_diff(
 
 /// Uses the result of [`diff_privileges`] to modify privileges in the database.
 pub async fn apply_privilege_diffs(
-    database_privilege_diffs: BTreeSet<DatabasePrivilegesDiff>,
+    database_privilege_diffs: &BTreeSet<DatabasePrivilegesDiff>,
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -468,12 +468,12 @@ pub async fn apply_privilege_diffs(
             Ok(true) => {}
         }
 
-        if let Err(err) = validate_diff(&diff, connection).await {
+        if let Err(err) = validate_diff(diff, connection).await {
             results.insert(key, Err(err));
             continue;
         }
 
-        let result = unsafe_apply_privilege_diff(&diff, connection)
+        let result = unsafe_apply_privilege_diff(diff, connection)
             .await
             .map_err(|e| ModifyDatabasePrivilegesError::MySqlError(e.to_string()));
 

src/server/sql/user_operations.rs

@@ -55,7 +55,7 @@ pub(super) async fn unsafe_user_exists(
 }
 
 pub async fn complete_user_name(
-    user_prefix: String,
+    user_prefix: &str,
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -95,7 +95,7 @@ pub async fn complete_user_name(
 }
 
 pub async fn create_database_users(
-    db_users: Vec<MySQLUser>,
+    db_users: &[MySQLUser],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -103,7 +103,7 @@ pub async fn create_database_users(
 ) -> CreateUsersResponse {
     let mut results = BTreeMap::new();
 
-    for db_user in db_users {
+    for db_user in db_users.iter().cloned() {
         if let Err(err) =
             validate_db_or_user_request(&DbOrUser::User(db_user.clone()), unix_user, group_denylist)
                 .map_err(CreateUserError::ValidationError)
@@ -141,7 +141,7 @@ pub async fn create_database_users(
 }
 
 pub async fn drop_database_users(
-    db_users: Vec<MySQLUser>,
+    db_users: &[MySQLUser],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     _db_is_mariadb: bool,
@@ -149,7 +149,7 @@ pub async fn drop_database_users(
 ) -> DropUsersResponse {
     let mut results = BTreeMap::new();
 
-    for db_user in db_users {
+    for db_user in db_users.iter().cloned() {
         if let Err(err) =
             validate_db_or_user_request(&DbOrUser::User(db_user.clone()), unix_user, group_denylist)
                 .map_err(DropUserError::ValidationError)
@@ -272,7 +272,7 @@ async fn database_user_is_locked_unsafe(
 }
 
 pub async fn lock_database_users(
-    db_users: Vec<MySQLUser>,
+    db_users: &[MySQLUser],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     db_is_mariadb: bool,
@@ -280,7 +280,7 @@ pub async fn lock_database_users(
 ) -> LockUsersResponse {
     let mut results = BTreeMap::new();
 
-    for db_user in db_users {
+    for db_user in db_users.iter().cloned() {
         if let Err(err) =
             validate_db_or_user_request(&DbOrUser::User(db_user.clone()), unix_user, group_denylist)
                 .map_err(LockUserError::ValidationError)
@@ -332,7 +332,7 @@ pub async fn lock_database_users(
 }
 
 pub async fn unlock_database_users(
-    db_users: Vec<MySQLUser>,
+    db_users: &[MySQLUser],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     db_is_mariadb: bool,
@@ -340,7 +340,7 @@ pub async fn unlock_database_users(
 ) -> UnlockUsersResponse {
     let mut results = BTreeMap::new();
 
-    for db_user in db_users {
+    for db_user in db_users.iter().cloned() {
         if let Err(err) =
             validate_db_or_user_request(&DbOrUser::User(db_user.clone()), unix_user, group_denylist)
                 .map_err(UnlockUserError::ValidationError)
@@ -440,7 +440,7 @@ FROM `user`
 ";
 
 pub async fn list_database_users(
-    db_users: Vec<MySQLUser>,
+    db_users: &[MySQLUser],
     unix_user: &UnixUser,
     connection: &mut MySqlConnection,
     db_is_mariadb: bool,
@@ -448,7 +448,7 @@ pub async fn list_database_users(
 ) -> ListUsersResponse {
     let mut results = BTreeMap::new();
 
-    for db_user in db_users {
+    for db_user in db_users.iter().cloned() {
         if let Err(err) =
             validate_db_or_user_request(&DbOrUser::User(db_user.clone()), unix_user, group_denylist)
                 .map_err(ListUsersError::ValidationError)

src/server/supervisor.rs

@@ -2,7 +2,10 @@ use std::{
     fs,
     os::{fd::FromRawFd, unix::net::UnixListener as StdUnixListener},
     path::PathBuf,
-    sync::Arc,
+    sync::{
+        Arc,
+        atomic::{AtomicU64, Ordering},
+    },
     time::Duration,
 };
 
@@ -22,7 +25,7 @@ use crate::{
     server::{
         authorization::read_and_parse_group_denylist,
         config::{MysqlConfig, ServerConfig},
-        session_handler::session_handler,
+        session_handler::{SessionId, session_handler},
     },
 };
 
@@ -548,6 +551,8 @@ async fn listener_task(
     #[cfg(target_os = "linux")]
     sd_notify::notify(false, &[sd_notify::NotifyState::Ready])?;
 
+    let connection_counter = AtomicU64::new(0);
+
     loop {
         tokio::select! {
             biased;
@@ -577,28 +582,29 @@ async fn listener_task(
             } => {
                 match accept_result {
                     Ok((conn, _addr)) => {
-                        tracing::debug!("Got new connection");
+                        connection_counter.fetch_add(1, Ordering::Relaxed);
+                        let conn_id = connection_counter.load(Ordering::Relaxed);
 
+                        tracing::debug!("Got new connection, assigned session ID {}", conn_id);
+
+                        let session_id = SessionId::new(conn_id);
                         let db_pool_clone = db_pool.clone();
                         let db_is_mariadb_clone = *db_is_mariadb.read().await;
                         let group_denylist_arc_clone = group_denylist.clone();
                         task_tracker.spawn(async move {
                             match session_handler(
                                 conn,
+                                session_id,
                                 db_pool_clone,
                                 db_is_mariadb_clone,
                                 &*group_denylist_arc_clone.read().await,
                             ).await {
-                                Ok(()) => {}
-                                Err(e) => {
-                                    tracing::error!("Failed to run server: {}", e);
-                                }
+                                Ok(()) => {},
+                                Err(e) => tracing::error!("Session {} failed: {}", conn_id, e),
                             }
                         });
-                    }
-                    Err(e) => {
-                        tracing::error!("Failed to accept new connection: {}", e);
-                    }
+                    },
+                    Err(e) => tracing::error!("Failed to accept new connection: {}", e),
                 }
             }
         }