Add test for reboot syscall

tests/system/main.rs

@@ -3,6 +3,8 @@
 #![cfg(feature = "system")]
 #![cfg(not(any(windows, target_os = "wasi")))]
 
+#[cfg(target_os = "linux")]
+mod reboot;
 #[cfg(linux_kernel)]
 mod sysinfo;
 mod uname;

tests/system/reboot.rs

@@ -0,0 +1,18 @@
+#[test]
+#[cfg(feature = "thread")]
+fn test_reboot() {
+    use rustix::{
+        io::Errno,
+        system::{self, RebootCommand},
+        thread::{self, CapabilityFlags},
+    };
+
+    let mut capabilities = thread::capabilities(None).expect("Failed to get capabilities");
+
+    capabilities.effective.set(CapabilityFlags::SYS_BOOT, false);
+
+    thread::set_capabilities(None, capabilities).expect("Failed to set capabilities");
+
+    // The reboot syscall requires the CAP_SYS_BOOT permission to be called, otherwise EPERM is returned
+    assert_eq!(system::reboot(RebootCommand::Restart), Err(Errno::PERM));
+}