Unhardcode user IDs

sidebus-broker/Cargo.toml

@@ -18,3 +18,4 @@ rustix = { version = "1.0.8", features = ["fs"] }
 url = "2.5.4"
 rand = "0.9.2"
 futures = "0.3.31"
+libc = "0.2.178"

sidebus-broker/src/main.rs

@@ -43,6 +43,14 @@ struct BrokerCli {
     /// Unix socket path to listen on for the VM bus
     #[clap(long)]
     unix_path: Option<PathBuf>,
+
+    /// The user ID for the appvm user inside of the guest
+    #[clap(long, default_value = "1337")]
+    guest_uid: u32,
+
+    /// The group ID for the appvm group inside of the guest
+    #[clap(long, default_value = "1337")]
+    guest_gid: u32,
 }
 
 async fn new_hosted_bus() -> eyre::Result<(
@@ -129,9 +137,9 @@ async fn main() -> eyre::Result<()> {
                 "--socket-path",
                 cli.runtime_dir.join("fs.sock").to_str().unwrap(),
                 "--uid-map",
-                ":1000:1001:1:",
+                &format!(":{}:{}:1:", cli.guest_uid, unsafe { libc::getuid() }),
                 "--gid-map",
-                ":100:100:1:",
+                &format!(":{}:{}:1:", cli.guest_gid, unsafe { libc::getgid() }),
                 "--log-level",
                 "debug",
             ])