Extract util module

1 files changed, 36 insertions, 0 deletions

diff --git a/src/util.rs b/src/util.rs
new file mode 100644
index 0000000..8302ed6
--- /dev/null
+++ b/src/util.rs
@@ -0,0 +1,36 @@
+use std::io::prelude::*;
+use std::io::{ErrorKind, self};
+use std::ffi::OsString;
+use std::os::unix::prelude::*;
+use libc::{gethostname, _SC_HOST_NAME_MAX};
+
+pub fn copy_stream(src: &mut dyn Read, dst: &mut dyn Write) -> io::Result<()> {
+    let mut buf = vec![0; 65536];
+    loop {
+        match src.read(&mut buf) {
+            Ok(0) => return Ok(()),
+            Ok(len) => dst.write_all(&buf[..len])?,
+            Err(e) if e.kind() == ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e),
+        }
+    }
+}
+
+pub fn hostname() -> OsString {
+    let mut bytes = vec![0; _SC_HOST_NAME_MAX as usize + 2];
+
+    if unsafe { gethostname(bytes.as_mut_ptr(), bytes.len()) } == -1 {
+        panic!("gethostname failed: {}", std::io::Error::last_os_error());
+    }
+
+    if bytes[_SC_HOST_NAME_MAX as usize + 1] != 0 {
+        panic!("hostname longer than HOST_NAME_MAX");
+    }
+
+    let bytes: Vec<_> = bytes
+        .into_iter()
+        .take_while(|b| *b != 0)
+        .map(|b| b as u8)
+        .collect();
+    OsString::from_vec(bytes)
+}