diff --git a/addons/bootstrap/user-groups_other.go b/addons/bootstrap/user-groups_other.go
new file mode 100644
index 00000000..20601663
--- /dev/null
+++ b/addons/bootstrap/user-groups_other.go
@@ -0,0 +1,12 @@
+//go:build !linux
+
+package bootstrap
+
+import (
+	"fmt"
+	"runtime"
+)
+
+func addUserToGroup(_ *Context, userName, groupName string) error {
+	return fmt.Errorf("adding user %s to group %s is not supported on %s", userName, groupName, runtime.GOOS)
+}
diff --git a/addons/diags/file-collector.go b/addons/diags/file-collector.go
index 4a8b5914..0ac4ca12 100644
--- a/addons/diags/file-collector.go
+++ b/addons/diags/file-collector.go
@@ -12,7 +12,6 @@ import (
 	"io/fs"
 	"os"
 	"sync"
-	"syscall"
 	"time"
 
 	"fastcat.org/go/gdev/instance"
@@ -91,12 +90,7 @@ func fillTarHeader(th *tar.Header, contents io.Reader) (bool, error) {
 		th.Size = fi.Size()
 		th.ModTime = fi.ModTime()
 		th.Mode = int64(fi.Mode().Perm())
-		if fis, ok := fi.Sys().(syscall.Stat_t); ok {
-			// don't bother trying to look up user information
-			th.Uid, th.Gid = int(fis.Uid), int(fis.Gid)
-			th.AccessTime = time.Unix(fis.Atim.Unix())
-			th.ChangeTime = time.Unix(fis.Ctim.Unix())
-		}
+		fillPlatformStatFields(th, fi)
 		return true, nil
 	}
 
diff --git a/addons/diags/stat-times_linux.go b/addons/diags/stat-times_linux.go
new file mode 100644
index 00000000..facd6bad
--- /dev/null
+++ b/addons/diags/stat-times_linux.go
@@ -0,0 +1,18 @@
+package diags
+
+import (
+	"archive/tar"
+	"io/fs"
+	"syscall"
+	"time"
+)
+
+func fillPlatformStatFields(th *tar.Header, fi fs.FileInfo) {
+	st, ok := fi.Sys().(*syscall.Stat_t)
+	if !ok {
+		return
+	}
+	th.Uid, th.Gid = int(st.Uid), int(st.Gid)
+	th.AccessTime = time.Unix(st.Atim.Unix())
+	th.ChangeTime = time.Unix(st.Ctim.Unix())
+}
diff --git a/addons/diags/stat-times_other.go b/addons/diags/stat-times_other.go
new file mode 100644
index 00000000..921806c6
--- /dev/null
+++ b/addons/diags/stat-times_other.go
@@ -0,0 +1,14 @@
+//go:build !linux
+
+package diags
+
+import (
+	"archive/tar"
+	"io/fs"
+)
+
+func fillPlatformStatFields(_ *tar.Header, _ fs.FileInfo) {
+	// On non-Linux platforms, Uid, Gid, AccessTime, and ChangeTime
+	// are left at their zero values. Darwin uses different syscall.Stat_t
+	// field names (Atimespec/Ctimespec) and Windows has no syscall.Stat_t.
+}
diff --git a/addons/pm/server/child.go b/addons/pm/server/child.go
index 213b8888..d3254c87 100644
--- a/addons/pm/server/child.go
+++ b/addons/pm/server/child.go
@@ -341,8 +341,7 @@ func (c *child) start(
 	for k, v := range e.Env {
 		cmd.Env = append(cmd.Env, k+"="+v)
 	}
-	// set pgid so we can kill process groups
-	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	setProcGroup(cmd)
 	// if logfile is not set, pass output to stdout/stderr and let journalctl
 	// capture it. note that this only works if we're using systemd for isolation.
 	if e.Logfile == "" {
@@ -388,16 +387,14 @@ func (c *child) start(
 }
 
 func (c *child) terminate(p *os.Process, s *api.ExecStatus) {
-	// signal the whole process group
-	if err := syscall.Kill(-p.Pid, syscall.SIGTERM); err != nil {
+	if err := terminateProcessGroup(p.Pid); err != nil {
 		log.Printf("failed to terminate %d: %v", p.Pid, err)
 	}
 	s.State = api.ExecStopping
 }
 
 func (c *child) kill(p *os.Process, s *api.ExecStatus) {
-	// signal the whole process group
-	if err := syscall.Kill(-p.Pid, syscall.SIGKILL); err != nil {
+	if err := killProcessGroup(p.Pid); err != nil {
 		log.Printf("failed to kill %d: %v", p.Pid, err)
 	}
 	if s.Group != "" {
diff --git a/addons/pm/server/proc_linux.go b/addons/pm/server/proc_linux.go
new file mode 100644
index 00000000..b69a9e4f
--- /dev/null
+++ b/addons/pm/server/proc_linux.go
@@ -0,0 +1,22 @@
+package server
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+// setProcGroup configures the command to start in a new process group,
+// enabling group-wide signal delivery via negative PID.
+func setProcGroup(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+}
+
+// terminateProcessGroup sends SIGTERM to the entire process group.
+func terminateProcessGroup(pid int) error {
+	return syscall.Kill(-pid, syscall.SIGTERM)
+}
+
+// killProcessGroup sends SIGKILL to the entire process group.
+func killProcessGroup(pid int) error {
+	return syscall.Kill(-pid, syscall.SIGKILL)
+}
diff --git a/addons/pm/server/proc_other.go b/addons/pm/server/proc_other.go
new file mode 100644
index 00000000..d3cf7f92
--- /dev/null
+++ b/addons/pm/server/proc_other.go
@@ -0,0 +1,19 @@
+//go:build !linux
+
+package server
+
+import (
+	"fmt"
+	"os/exec"
+	"runtime"
+)
+
+func setProcGroup(_ *exec.Cmd) {}
+
+func terminateProcessGroup(_ int) error {
+	return fmt.Errorf("process group termination not supported on %s", runtime.GOOS)
+}
+
+func killProcessGroup(_ int) error {
+	return fmt.Errorf("process group kill not supported on %s", runtime.GOOS)
+}
diff --git a/instance/version.go b/instance/version.go
index d188d27c..e5e5a5db 100644
--- a/instance/version.go
+++ b/instance/version.go
@@ -8,12 +8,28 @@ import (
 
 var info = sync.OnceValue(loadVersionInfo)
 
+// versionOverride, if non-empty, replaces MainVersion from build info.
+var versionOverride string
+
+// SetVersion overrides the main version string reported by Version() and
+// VersionInfo(). Call before any use of the version functions.
+func SetVersion(v string) {
+	versionOverride = v
+}
+
 func Version() string {
+	if versionOverride != "" {
+		return versionOverride
+	}
 	return info().MainVersion
 }
 
 func VersionInfo() versionInfo {
-	return info()
+	vi := info()
+	if versionOverride != "" {
+		vi.MainVersion = versionOverride
+	}
+	return vi
 }
 
 type versionInfo struct {
diff --git a/lib/sys/daemon_other.go b/lib/sys/daemon_other.go
index 02cc0421..3a145050 100644
--- a/lib/sys/daemon_other.go
+++ b/lib/sys/daemon_other.go
@@ -8,6 +8,12 @@ import (
 	"runtime"
 )
 
+// FallbackLogFileEnv is an environment variable that can be set to provide
+// a fallback log file path for daemons started without systemd support.
+//
+// This will not be passed to the actual daemon.
+const FallbackLogFileEnv = "__FALLBACK_LOG_FILE"
+
 func StartDaemon(
 	ctx context.Context,
 	name string,