feat: added FreeBSD support

to make use of it, create a FreeBSD VM with curl installed and install
rustup by default from rustup.rs, then run `cargo build -p sparse-05-server`

sparse-05/sparse-05-server/src/capabilities.rs

@@ -2,6 +2,7 @@
 use std::ffi::c_int;
 use std::path::PathBuf;
 
+use anyhow::Context;
 use sparse_05_common::messages::{Capabilities, OperatingSystem, TransportType};
 
 #[derive(Debug)]
@@ -60,7 +61,7 @@ struct cap_user_data_t {
     inheritable: u32,
 }
 
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", target_os = "freebsd"))]
 fn get_username(uid: u32) -> anyhow::Result<Option<String>> {
     let passwd = std::fs::read_to_string("/etc/passwd")?;
 
@@ -118,11 +119,7 @@ fn get_current_capabilities() -> anyhow::Result<SrvCapabilities> {
         .ok();
 
     Ok(SrvCapabilities {
-        operating_system: if cfg!(target_os = "linux") {
-            OperatingSystem::Linux
-        } else {
-            OperatingSystem::Windows
-        },
+        operating_system: OperatingSystem::Linux,
         docker_container,
         docker_breakout,
         setuid,
@@ -153,6 +150,31 @@ fn get_current_capabilities() -> anyhow::Result<SrvCapabilities> {
     })
 }
 
+#[cfg(target_os = "freebsd")]
+fn get_current_capabilities() -> anyhow::Result<SrvCapabilities> {
+    let uid = unsafe { libc::getuid() };
+    let root = uid == 0;
+    let userent = get_username(uid)?;
+    let hostname = std::fs::read_to_string("/etc/rc.conf")?
+        .split("\n")
+        .map(|line| line.split("=").collect::<Vec<_>>())
+        .find(|line| line.get(0) == Some(&"hostname"))
+        .map(|line| line.get(1).map(|name| name.to_string()))
+        .flatten();
+
+    Ok(SrvCapabilities {
+        operating_system: OperatingSystem::FreeBSD,
+        docker_container: false,
+        docker_breakout: false,
+        setuid: false,
+        service: false,
+        root,
+        userent: userent.clone(),
+        transport: TransportType::RawUdp,
+        hostname,
+    })
+}
+
 pub fn get_capabilities() -> anyhow::Result<SrvCapabilities> {
     get_current_capabilities()
 }