diff --git a/agent/src/main.rs b/agent/src/main.rs
index 4705440..7f0b2a1 100644
--- a/agent/src/main.rs
+++ b/agent/src/main.rs
@@ -908,6 +908,7 @@ fn zfs_get(dataset: &str, prop: &str) -> Result<String> {
     Ok(l[0].to_string())
 }
 
+#[cfg_attr(not(target_os = "illumos"), expect(dead_code))]
 fn zfs_set(dataset: &str, prop: &str, value: &str) -> Result<()> {
     let out = Command::new("/sbin/zfs")
         .arg("set")
diff --git a/factory/gimlet/Cargo.toml b/factory/gimlet/Cargo.toml
index d06386d..3581ebf 100644
--- a/factory/gimlet/Cargo.toml
+++ b/factory/gimlet/Cargo.toml
@@ -14,7 +14,6 @@ buildomat-types = { path = "../../types" }
 anyhow = { workspace = true }
 chrono = { workspace = true }
 debug_parser = { workspace = true }
-devinfo = { workspace = true }
 dropshot = { workspace = true }
 getopts = { workspace = true }
 hyper = { workspace = true }
@@ -33,3 +32,6 @@ tokio = { workspace = true }
 toml = { workspace = true }
 usdt = { workspace = true }
 uuid = { workspace = true }
+
+[target.'cfg(target_os = "illumos")'.dependencies]
+devinfo = { workspace = true }
diff --git a/factory/gimlet/src/cleanup.rs b/factory/gimlet/src/cleanup.rs
index 2919a57..a98ed65 100644
--- a/factory/gimlet/src/cleanup.rs
+++ b/factory/gimlet/src/cleanup.rs
@@ -11,8 +11,7 @@ use std::{
 use anyhow::{anyhow, bail, Result};
 use buildomat_common::*;
 
-use crate::{disks, efi};
-use disks::Slot;
+use crate::disks::{self, Slot};
 
 #[derive(Debug)]
 struct Status {
@@ -210,7 +209,10 @@ pub fn cleanup() -> Result<()> {
     Ok(())
 }
 
+#[cfg(target_os = "illumos")]
 fn prepare_m2() -> Result<()> {
+    use crate::efi;
+
     let disks = disks::list_disks()?;
 
     let Some(d) = disks.get(&Slot::M2(0)) else {
@@ -305,6 +307,11 @@ fn prepare_m2() -> Result<()> {
     Ok(())
 }
 
+#[cfg(not(target_os = "illumos"))]
+fn prepare_m2() -> Result<()> {
+    bail!("only works on illumos systems");
+}
+
 fn format_disks() -> Result<()> {
     /*
      * First, list the disks in the system.  We expect there to be two M.2 SSDs
diff --git a/factory/gimlet/src/main.rs b/factory/gimlet/src/main.rs
index 6271e81..db0562b 100644
--- a/factory/gimlet/src/main.rs
+++ b/factory/gimlet/src/main.rs
@@ -30,6 +30,7 @@ mod cleanup;
 mod config;
 mod db;
 mod disks;
+#[cfg(target_os = "illumos")]
 mod efi;
 mod factory;
 mod host;
diff --git a/factory/propolis/src/main.rs b/factory/propolis/src/main.rs
index 7e0cde2..3d0aa46 100644
--- a/factory/propolis/src/main.rs
+++ b/factory/propolis/src/main.rs
@@ -18,6 +18,7 @@ mod nocloud;
 mod propolis;
 mod serial;
 mod svc;
+#[cfg(target_os = "illumos")]
 mod ucred;
 mod vm;
 mod zones;
diff --git a/factory/propolis/src/serial.rs b/factory/propolis/src/serial.rs
index c6eab11..6dfd565 100644
--- a/factory/propolis/src/serial.rs
+++ b/factory/propolis/src/serial.rs
@@ -10,6 +10,7 @@ use std::{
     time::Duration,
 };
 
+#[cfg(target_os = "illumos")]
 use crate::ucred::PeerUCred;
 use crate::zones::*;
 use anyhow::{anyhow, bail, Result};
@@ -25,7 +26,7 @@ pub enum SerialData {
 
 pub struct SerialForZone {
     name: String,
-    zoneid: zoneid_t,
+    zoneid: ZoneId,
     rx: tokio::sync::mpsc::Receiver<SerialData>,
     shutdown: tokio::sync::watch::Sender<bool>,
     inner: Arc<Inner>,
@@ -42,6 +43,7 @@ impl SerialForZone {
          * Remove the zone from the active set and shut down any socket tasks.
          */
         let mut zones = self.inner.zones.lock().unwrap();
+        #[cfg_attr(not(target_os = "illumos"), expect(unused))]
         let removed = zones.remove(&self.zoneid).unwrap();
         assert_eq!(removed.name, self.name);
         assert_eq!(removed.zoneid, self.zoneid);
@@ -69,13 +71,13 @@ pub struct Serial(Arc<Inner>);
 #[derive(Clone)]
 struct Zone {
     name: String,
-    zoneid: zoneid_t,
+    zoneid: ZoneId,
     tx: tokio::sync::mpsc::Sender<SerialData>,
     shutdown: tokio::sync::watch::Receiver<bool>,
 }
 
 pub struct Inner {
-    zones: Mutex<HashMap<zoneid_t, Zone>>,
+    zones: Mutex<HashMap<ZoneId, Zone>>,
 }
 
 impl Serial {
@@ -114,10 +116,15 @@ impl Serial {
         Ok(s0)
     }
 
+    #[cfg_attr(not(target_os = "illumos"), expect(unused))]
     async fn accept_task(&self, log: Logger, listen: UnixListener) -> ! {
         loop {
-            let (sock, zoneid) = match listen.accept().await {
+            let (sock, zoneid): (UnixStream, ZoneId) = match listen
+                .accept()
+                .await
+            {
                 Ok((sock, _)) => {
+                    #[cfg(target_os = "illumos")]
                     match sock.peer_ucred() {
                         Ok(uc) => {
                             let Some(zoneid) = uc.zoneid() else {
@@ -125,7 +132,7 @@ impl Serial {
                                 continue;
                             };
 
-                            if zoneid == 0 {
+                            if zoneid.0 == 0 {
                                 /*
                                  * We never want connections from the global
                                  * zone.
@@ -142,6 +149,12 @@ impl Serial {
                         }
                     }
 
+                    #[cfg(not(target_os = "illumos"))]
+                    {
+                        error!(log, "only works on illumos");
+                        continue;
+                    }
+
                     /*
                      * Then we need to determine if this is a zone that we
                      * actually want to hear from or not.
diff --git a/factory/propolis/src/ucred.rs b/factory/propolis/src/ucred.rs
index a1c9c02..3b9caac 100644
--- a/factory/propolis/src/ucred.rs
+++ b/factory/propolis/src/ucred.rs
@@ -5,7 +5,9 @@
 use std::os::fd::AsRawFd;
 
 use anyhow::{bail, Result};
-use libc::{getpeerucred, ucred_free, ucred_getzoneid, ucred_t, zoneid_t};
+use libc::{getpeerucred, ucred_free, ucred_getzoneid, ucred_t};
+
+use crate::zones::ZoneId;
 
 pub trait PeerUCred: AsRawFd {
     fn peer_ucred(&self) -> Result<UCred> {
@@ -37,7 +39,7 @@ impl Drop for UCred {
 }
 
 impl UCred {
-    pub fn zoneid(&self) -> Option<zoneid_t> {
+    pub fn zoneid(&self) -> Option<ZoneId> {
         let zoneid = unsafe { ucred_getzoneid(self.uc) };
         if zoneid < 0 {
             None
diff --git a/factory/propolis/src/zones.rs b/factory/propolis/src/zones.rs
index 285a152..15c3a73 100644
--- a/factory/propolis/src/zones.rs
+++ b/factory/propolis/src/zones.rs
@@ -2,18 +2,40 @@
  * Copyright 2024 Oxide Computer Company
  */
 
-use std::ffi::CString;
-
 use anyhow::{bail, Result};
-pub use libc::zoneid_t;
 
-#[link(name = "c")]
-extern "C" {
-    fn getzoneidbyname(name: *const libc::c_char) -> zoneid_t;
+#[cfg(target_os = "illumos")]
+type ZoneIdInner = libc::zoneid_t;
+/*
+ * "Infallible" is the stable equivalent of the never type (!).  It can not be
+ * instantiated, ensuring that we never construct a ZoneId outside illumos.
+ */
+#[cfg(not(target_os = "illumos"))]
+type ZoneIdInner = std::convert::Infallible;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct ZoneId(pub ZoneIdInner);
+
+impl std::fmt::Display for ZoneId {
+    #[cfg(target_os = "illumos")]
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+
+    #[cfg(not(target_os = "illumos"))]
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("ZoneId")
+    }
 }
 
-pub fn zone_name_to_id(name: &str) -> Result<Option<zoneid_t>> {
-    let cs = CString::new(name)?;
+#[cfg(target_os = "illumos")]
+pub fn zone_name_to_id(name: &str) -> Result<Option<ZoneId>> {
+    #[link(name = "c")]
+    extern "C" {
+        fn getzoneidbyname(name: *const libc::c_char) -> zoneid_t;
+    }
+
+    let cs = std::ffi::CString::new(name)?;
 
     let id = unsafe { getzoneidbyname(cs.as_ptr()) };
     if id < 0 {
@@ -30,7 +52,12 @@ pub fn zone_name_to_id(name: &str) -> Result<Option<zoneid_t>> {
         bail!("getzoneidbyname({name}): {e}");
     }
 
-    Ok(Some(id))
+    Ok(Some(ZoneId(id)))
+}
+
+#[cfg(not(target_os = "illumos"))]
+pub fn zone_name_to_id(_name: &str) -> Result<Option<ZoneId>> {
+    bail!("only works on illumos systems");
 }
 
 pub fn zone_exists(name: &str) -> Result<bool> {