Add references

src/lib.rs

@@ -62,6 +62,24 @@ pub fn gethostname() -> OsString {
 fn gethostname_impl() -> OsString {
     use std::os::unix::ffi::OsStringExt;
 
+    // libc::gethostname() is implemented in both musl and glibc by calling uname() and copying
+    // the nodename field into the buffer.
+    //
+    // glibc:
+    // https://github.com/lattera/glibc/blob/895ef79e04a953cac1493863bcae29ad85657ee1/sysdeps/posix/gethostname.c#L32-L36
+    // musl:
+    // https://github.com/cloudius-systems/musl/blob/00733dd1cf791d13ff6155509cf139a5f7b2eecb/src/unistd/gethostname.c#L4-L13
+    //
+    // On FreeBSD, libc::gethostname() is a sysctl call to KERN_HOSTNAME. uname() fetches the nodename
+    // using the same strategy.
+    //
+    // freebsd gethostname:
+    // https://github.com/FreeBSDDesktop/freebsd-base/blob/de1aa3dab23c06fec962a14da3e7b4755c5880cf/lib/libc/gen/gethostname.c#L47-L54
+    // freebsd uname:
+    // https://github.com/FreeBSDDesktop/freebsd-base/blob/de1aa3dab23c06fec962a14da3e7b4755c5880cf/lib/libc/gen/__xuname.c#L73-L83
+    //
+    // OpenBSD uses the same strategy, so I doubt that other implementations of uname() among the BSDs
+    // stray too far from this pattern.
     let bytes = rustix::process::uname().nodename().to_bytes().to_vec();
     OsString::from_vec(bytes)
 }