all: sync with master

internal/aghos/os.go

@@ -168,11 +168,11 @@ func IsOpenWrt() (ok bool) {
 	return isOpenWrt()
 }
 
-// RootDirFS returns the fs.FS rooted at the operating system's root.
+// RootDirFS returns the [fs.FS] rooted at the operating system's root.  On
+// Windows it returns the fs.FS rooted at the volume of the system directory
+// (usually, C:).
 func RootDirFS() (fsys fs.FS) {
-	// Use empty string since os.DirFS implicitly prepends a slash to it.  This
-	// behavior is undocumented but it currently works.
-	return os.DirFS("")
+	return rootDirFS()
 }
 
 // NotifyReconfigureSignal notifies c on receiving reconfigure signals.

internal/aghos/os_unix.go

@@ -3,12 +3,17 @@
 package aghos
 
 import (
+	"io/fs"
 	"os"
 	"os/signal"
 
 	"golang.org/x/sys/unix"
 )
 
+func rootDirFS() (fsys fs.FS) {
+	return os.DirFS("/")
+}
+
 func notifyReconfigureSignal(c chan<- os.Signal) {
 	signal.Notify(c, unix.SIGHUP)
 }

internal/aghos/os_windows.go

@@ -3,13 +3,29 @@
 package aghos
 
 import (
+	"io/fs"
 	"os"
 	"os/signal"
+	"path/filepath"
 	"syscall"
 
+	"github.com/AdguardTeam/golibs/log"
 	"golang.org/x/sys/windows"
 )
 
+func rootDirFS() (fsys fs.FS) {
+	// TODO(a.garipov): Use a better way if golang/go#44279 is ever resolved.
+	sysDir, err := windows.GetSystemDirectory()
+	if err != nil {
+		log.Error("aghos: getting root filesystem: %s; using C:", err)
+
+		// Assume that C: is the safe default.
+		return os.DirFS("C:")
+	}
+
+	return os.DirFS(filepath.VolumeName(sysDir))
+}
+
 func setRlimit(val uint64) (err error) {
 	return Unsupported("setrlimit")
 }