1 files changed, 53 insertions, 0 deletions
diff --git a/init/src/host/set.rs b/init/src/host/set.rs
new file mode 100644
index 0000000..9550b29
--- /dev/null
+++ b/init/src/host/set.rs
@@ -0,0 +1,53 @@
+use crate::log::log_warning;
+use libc::{c_char, sethostname, size_t};
+use std::{ffi::CString, fs, io};
+
+pub fn set_hostname() -> Result<(), Box<dyn std::error::Error>> {
+    let content = fs::read_to_string("/etc/hostname")
+        .map(|s| s.trim().to_string())
+        .unwrap_or_else(|_| "localhost".to_string());
+
+    if let Err(e) = perform_set_hostname(&content) {
+        match perform_set_hostname("localhost") {
+            Ok(_) => Err(format!(
+                "Failed to set hostname: \"{}\": {}. Fell back to localhost successfully.",
+                content, e
+            )
+            .into()),
+
+            Err(fallback_error) => {
+                log_warning(&format!(
+                    "Failed to set hostname to '{}': {}. Also failed to set localhost: {}.",
+                    content, e, fallback_error
+                ));
+                Err(format!(
+                    "Failed to set hostname '{}' and failed to fall back to localhost: {}.",
+                    content, e
+                )
+                .into())
+            }
+        }
+    } else {
+        Ok(())
+    }
+}
+
+fn perform_set_hostname(name: &str) -> io::Result<()> {
+    if name.len() > 64 {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidInput,
+            "Hostname too long",
+        ));
+    }
+
+    let c_str = CString::new(name)
+        .map_err(|_| io::Error::new(io::ErrorKind::InvalidInput, "Hostname contains null byte"))?;
+
+    let res = unsafe { sethostname(c_str.as_ptr() as *const c_char, name.len() as size_t) };
+
+    if res != 0 {
+        return Err(io::Error::last_os_error());
+    }
+
+    Ok(())
+}