guest: set an /etc/hostname if we don't have one

hotfix, see comment.

Signed-off-by: Alyssa Rosenzweig <[email protected]>

crates/muvm/src/guest/mount.rs

@@ -1,5 +1,5 @@
 use std::ffi::CString;
-use std::fs::{read_dir, File};
+use std::fs::{read_dir, exists, File};
 use std::io::Write;
 use std::os::fd::AsFd;
 use std::path::Path;
@@ -135,6 +135,22 @@ pub fn mount_filesystems() -> Result<()> {
 
     place_etc("resolv.conf", None)?;
 
+    // Due to a FAR integration bug, GNOME installs may not have /etc/hostname. Somehow the system
+    // mostly works like that? But Steam install depends on this file. If there's no hostname set
+    // in the host, at least make up a hostname for the guest so the Steam install works in the
+    // guest.
+    //
+    // This is a hot fix but doesn't have any real drawbacks as a bit of robustness against broken
+    // host installs.
+    //
+    // FAR bug: https://pagure.io/fedora-asahi/remix-bugs/issue/11
+    //
+    // (Although even after that's closed, we won't be able to drop this for a while because
+    // existing installs may be affected.)
+    if !exists("/etc/hostname")? {
+        place_etc("hostname", Some("placeholder-hostname"))?;
+    }
+
     mount2(
         Some("binfmt_misc"),
         "/proc/sys/fs/binfmt_misc",