rpi: throw an error when trying to run the 32-bit server on 64-bit OS and vice-versa

internal/staticsources/rpicamera/camera.go

@@ -51,7 +51,7 @@ func (c *camera) initialize() error {
 		"LD_LIBRARY_PATH=" + dumpPath,
 	}
 
-	c.cmd = exec.Command(filepath.Join(dumpPath, "mtxrpicam"))
+	c.cmd = exec.Command(filepath.Join(dumpPath, executableName))
 	c.cmd.Stdout = os.Stdout
 	c.cmd.Stderr = os.Stderr
 	c.cmd.Env = env

internal/staticsources/rpicamera/component.go

@@ -4,17 +4,22 @@
 package rpicamera
 
 import (
+	"debug/elf"
+	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
+	"runtime"
 	"strconv"
+	"strings"
 	"sync"
 	"time"
 )
 
-//go:generate go run ./mtxrpicamdownloader
-
 const (
-	dumpPrefix = "/dev/shm/mediamtx-rpicamera-"
+	libraryToCheckArchitecture = "libc.so.6"
+	dumpPrefix                 = "/dev/shm/mediamtx-rpicamera-"
+	executableName             = "mtxrpicam"
 )
 
 var (
@@ -23,6 +28,55 @@ var (
 	dumpPath  = ""
 )
 
+func getArchitecture(libPath string) (bool, error) {
+	f, err := os.Open(libPath)
+	if err != nil {
+		return false, err
+	}
+	defer f.Close()
+
+	ef, err := elf.NewFile(f)
+	if err != nil {
+		return false, err
+	}
+	defer ef.Close()
+
+	return (ef.FileHeader.Class == elf.ELFCLASS64), nil
+}
+
+func checkArchitecture() error {
+	byts, err := exec.Command("ldconfig", "-p").Output()
+	if err != nil {
+		return fmt.Errorf("ldconfig failed: %w", err)
+	}
+
+	for _, line := range strings.Split(string(byts), "\n") {
+		f := strings.Split(line, " => ")
+		if len(f) == 2 && strings.Contains(f[1], libraryToCheckArchitecture) {
+			is64, err := getArchitecture(f[1])
+			if err != nil {
+				return err
+			}
+
+			if runtime.GOARCH == "arm" {
+				if !is64 {
+					return nil
+				}
+			} else {
+				if is64 {
+					return nil
+				}
+			}
+		}
+	}
+
+	if runtime.GOARCH == "arm" {
+		return fmt.Errorf("the operating system is 64-bit, you need the 64-bit server version")
+	}
+
+	return fmt.Errorf("the operating system is 32-bit, you need the 32-bit server version")
+}
+
 func dumpEmbedFSRecursive(src string, dest string) error {
 	files, err := component.ReadDir(src)
 	if err != nil {
@@ -65,9 +119,14 @@ func dumpComponent() error {
 		return nil
 	}
 
+	err := checkArchitecture()
+	if err != nil {
+		return err
+	}
+
 	dumpPath = dumpPrefix + strconv.FormatInt(time.Now().UnixNano(), 10)
 
-	err := os.Mkdir(dumpPath, 0o755)
+	err = os.Mkdir(dumpPath, 0o755)
 	if err != nil {
 		return err
 	}
@@ -84,7 +143,7 @@ func dumpComponent() error {
 		return err
 	}
 
-	err = os.Chmod(filepath.Join(dumpPath, "mtxrpicam"), 0o755)
+	err = os.Chmod(filepath.Join(dumpPath, executableName), 0o755)
 	if err != nil {
 		os.RemoveAll(dumpPath)
 		return err