Add exclusive process lock to Kanidm to prevent accidental duplicate commands. (#1575)

Cargo.lock

@@ -1151,6 +1151,7 @@ version = "1.1.0-alpha.12-dev"
 dependencies = [
  "clap",
  "clap_complete",
+ "fs2",
  "kanidm_lib_file_permissions",
  "kanidm_proto",
  "kanidmd_core",
@@ -1519,6 +1520,16 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "fs2"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9564fc758e15025b46aa6643b1b77d047d1a56a1aea6e01002ac0c7026876213"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "futures"
 version = "0.3.28"

Cargo.toml

@@ -59,6 +59,7 @@ dialoguer = "0.10.4"
 dyn-clone = "^1.0.11"
 fernet = "^0.2.1"
 filetime = "^0.2.21"
+fs2 = "^0.4.3"
 futures = "^0.3.28"
 futures-concurrency = "^3.1.0"
 futures-util = { version = "^0.3.21", features = ["sink"] }

server/daemon/Cargo.toml

@@ -22,6 +22,7 @@ kanidm_proto.workspace = true
 kanidmd_core.workspace = true
 kanidm_lib_file_permissions.workspace = true
 sketching.workspace = true
+fs2.workspace = true
 
 clap = { workspace = true, features = ["env"] }
 reqwest = { workspace = true }

server/daemon/src/main.rs

@@ -14,7 +14,9 @@
 #[global_allocator]
 static ALLOC: tikv_jemallocator::Jemalloc = tikv_jemallocator::Jemalloc;
 
-use std::fs::metadata;
+use std::fs::{metadata, File};
+// This works on both unix and windows.
+use fs2::FileExt;
 #[cfg(target_family = "unix")]
 use std::os::unix::fs::MetadataExt;
 use std::path::PathBuf;
@@ -235,6 +237,25 @@ async fn main() -> ExitCode {
             config.update_output_mode(opt.commands.commonopt().output_mode.to_owned().into());
             config.update_trust_x_forward_for(sconfig.trust_x_forward_for);
 
+            // Okay - Lets now create our lock and go.
+            let klock_path = format!("{}.klock" ,sconfig.db_path.as_str());
+            let flock = match File::create(&klock_path) {
+                Ok(flock) => flock,
+                Err(e) => {
+                    error!("ERROR: Refusing to start - unable to create kanidm exclusive lock at {} - {:?}", klock_path, e);
+                    return ExitCode::FAILURE
+                }
+            };
+
+            match flock.try_lock_exclusive() {
+                Ok(()) => debug!("Acquired kanidm exclusive lock"),
+                Err(e) => {
+                    error!("ERROR: Refusing to start - unable to lock kanidm exclusive lock at {} - {:?}", klock_path, e);
+                    error!("Is another kanidm process running?");
+                    return ExitCode::FAILURE
+                }
+            };
+
             /*
             // Apply any cli overrides, normally debug level.
             if opt.commands.commonopt().debug.as_ref() {

server/lib/src/be/idl_sqlite.rs

@@ -1440,7 +1440,10 @@ impl IdlSqlite {
         // Enable WAL mode, which is just faster and better for our needs.
         let mut flags = OpenFlags::default();
         // Open with multi thread flags and locking options.
+
+        if cfg!(test) {
             flags.insert(OpenFlags::SQLITE_OPEN_NO_MUTEX);
+        };
 
         // We need to run vacuum in the setup else we hit sqlite lock conditions.
         if vacuum {