149 lines
3.5 KiB
Go
149 lines
3.5 KiB
Go
//go:build linux
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/*
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* ============================================================================
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* Projekt.....: rs2322tcp
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* Datei.......: internal/client/virtual_port_linux.go
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* Copyright (C) 2026 Dieter Lang
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*
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* SPDX-License-Identifier: GPL-3.0-or-later
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*
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* Beschreibung:
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* Linux-spezifische Verwaltung der internen Symlinks für virtuelle
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* rs2322tcp-Seriellschnittstellen.
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*
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* Der öffentliche Gerätename /dev/ttyUSBxxx wird bei der Installation
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* vorbereitet. Der Client verwaltet ausschließlich den benutzerbezogenen
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* Link unter ~/.rs2322tcp/virtual/.
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* ============================================================================
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*/
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package client
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import (
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"fmt"
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"os"
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"path/filepath"
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)
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const (
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virtualDirectoryName = ".rs2322tcp/virtual"
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)
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// virtualPortDirectory returns the directory in the current user's home
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// directory used for the internal virtual-port links.
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func virtualPortDirectory() (string, error) {
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home, err := os.UserHomeDir()
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if err != nil {
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return "", fmt.Errorf("get user home directory: %w", err)
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}
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return filepath.Join(home, virtualDirectoryName), nil
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}
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// virtualPortLinkPath returns the path of the internal link for a virtual
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// serial port.
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func virtualPortLinkPath(portPath string) (string, error) {
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directory, err := virtualPortDirectory()
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if err != nil {
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return "", err
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}
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return filepath.Join(directory, filepath.Base(portPath)), nil
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}
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// ensureVirtualPortDirectory creates the internal virtual-port directory
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// if it does not already exist.
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func ensureVirtualPortDirectory() error {
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directory, err := virtualPortDirectory()
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if err != nil {
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return err
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}
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if err := os.MkdirAll(directory, 0755); err != nil {
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return fmt.Errorf(
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"create virtual port directory %q: %w",
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directory,
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err,
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)
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}
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return nil
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}
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// setVirtualPortLink creates or replaces the internal link for a virtual
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// port.
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//
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// The link itself is located below ~/.rs2322tcp/virtual/ and points to the
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// current PTY, for example /dev/pts/2.
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//
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// The public /dev/ttyUSBxxx installation link is deliberately never
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// modified here.
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func setVirtualPortLink(portPath string, target string) error {
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if portPath == "" {
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return fmt.Errorf("virtual port path is empty")
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}
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if target == "" {
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return fmt.Errorf("virtual port target is empty")
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}
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if err := ensureVirtualPortDirectory(); err != nil {
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return err
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}
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linkPath, err := virtualPortLinkPath(portPath)
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if err != nil {
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return err
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}
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// Replace only the user-owned internal link.
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//
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// The installation-owned /dev/ttyUSBxxx link is deliberately never
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// touched here.
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if err := os.Remove(linkPath); err != nil && !os.IsNotExist(err) {
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return fmt.Errorf(
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"remove existing virtual port link %q: %w",
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linkPath,
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err,
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)
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}
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if err := os.Symlink(target, linkPath); err != nil {
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return fmt.Errorf(
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"create virtual port link %q -> %q: %w",
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linkPath,
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target,
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err,
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)
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}
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return nil
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}
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// removeVirtualPortLink removes the user-owned internal link for a virtual
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// port.
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//
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// This function is retained for explicit link-management operations and
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// tests. It is NOT called by ManagedVirtualPort.Close(), because the
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// installation-owned symlink chain must remain available.
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func removeVirtualPortLink(portPath string) error {
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if portPath == "" {
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return fmt.Errorf("virtual port path is empty")
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}
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linkPath, err := virtualPortLinkPath(portPath)
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if err != nil {
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return err
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}
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if err := os.Remove(linkPath); err != nil && !os.IsNotExist(err) {
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return fmt.Errorf(
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"remove existing virtual port link %q: %w",
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linkPath,
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err,
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)
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}
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return nil
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}
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