ignore EROFS and EPERM errors on config saving

agent still works in remote mode and executable environment may not
allow to save any data at all (e.g. in k8s container), so be robust.

Signed-off-by: Alex Lyashko <alex.lyashko@gmail.com>

agent/agent.go

@@ -10,6 +10,7 @@ import (
 	"bufio"
 	"context"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -145,12 +146,18 @@ func saveConfig(opts Options, port int) (err error) {
 	}
 
 	err = os.MkdirAll(gopsdir, os.ModePerm)
+	if errors.Is(err, syscall.EROFS) || errors.Is(err, syscall.EPERM) { // ignore and work in remote mode only
+		return nil
+	}
 	if err != nil {
 		return err
 	}
 
 	portfile = filepath.Join(gopsdir, strconv.Itoa(os.Getpid()))
 	err = os.WriteFile(portfile, []byte(strconv.Itoa(port)), os.ModePerm)
+	if errors.Is(err, syscall.EROFS) || errors.Is(err, syscall.EPERM) { // ignore and work in remote mode only
+		return nil
+	}
 	if err != nil {
 		return err
 	}