Initial commit

internal/cpu/cpu.go

@@ -0,0 +1,117 @@
+/*
+ * LURE - Linux User REpository
+ * Copyright (C) 2023 Elara Musayelyan
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package cpu
+
+import (
+	"os"
+	"runtime"
+	"strconv"
+	"strings"
+
+	"golang.org/x/exp/slices"
+	"golang.org/x/sys/cpu"
+)
+
+// armVariant checks which variant of ARM lure is running
+// on, by using the same detection method as Go itself
+func armVariant() string {
+	armEnv := os.Getenv("LURE_ARM_VARIANT")
+	// ensure value has "arm" prefix, such as arm5 or arm6
+	if strings.HasPrefix(armEnv, "arm") {
+		return armEnv
+	}
+
+	if cpu.ARM.HasVFPv3 {
+		return "arm7"
+	} else if cpu.ARM.HasVFP {
+		return "arm6"
+	} else {
+		return "arm5"
+	}
+}
+
+// Arch returns the canonical CPU architecture of the system
+func Arch() string {
+	arch := os.Getenv("LURE_ARCH")
+	if arch == "" {
+		arch = runtime.GOARCH
+	}
+	if arch == "arm" {
+		arch = armVariant()
+	}
+	return arch
+}
+
+func IsCompatibleWith(target string, list []string) bool {
+	if target == "all" || slices.Contains(list, "all") {
+		return true
+	}
+
+	for _, arch := range list {
+		if strings.HasPrefix(target, "arm") && strings.HasPrefix(arch, "arm") {
+			targetVer, err := getARMVersion(target)
+			if err != nil {
+				return false
+			}
+
+			archVer, err := getARMVersion(arch)
+			if err != nil {
+				return false
+			}
+
+			if targetVer >= archVer {
+				return true
+			}
+		}
+
+		if target == arch {
+			return true
+		}
+	}
+
+	return false
+}
+
+func CompatibleArches(arch string) ([]string, error) {
+	if strings.HasPrefix(arch, "arm") {
+		ver, err := getARMVersion(arch)
+		if err != nil {
+			return nil, err
+		}
+
+		if ver > 5 {
+			var out []string
+			for i := ver; i >= 5; i-- {
+				out = append(out, "arm"+strconv.Itoa(i))
+			}
+			return out, nil
+		}
+	}
+
+	return []string{arch}, nil
+}
+
+func getARMVersion(arch string) (int, error) {
+	// Extract the version number from ARM architecture
+	version := strings.TrimPrefix(arch, "arm")
+	if version == "" {
+		return 5, nil // Default to arm5 if version is not specified
+	}
+	return strconv.Atoi(version)
+}