bsncubed
23dcfb393f
Implements the design in claude.md as a building skeleton: pure Go, no cgo, cross-compiles to a single Windows .exe from Linux. Architecture follows the spec's deliberate split. The fast path is native — tray icon, grouped submenus, a Win32 MessageBox showing a live before/after diff, then netsh. The slow path is an embedded web editor served on a random loopback port and opened in the default browser. Two decisions worth recording: Reads use GetAdaptersAddresses, writes use netsh. The spec left the enumeration mechanism open; parsing `netsh show config` breaks on a non-English Windows because the output is localised. DNS static-vs-DHCP origin is not exposed by that API, so it comes from one registry read. The netsh command plan is built in portable code. That puts the delete-every- existing-address step — the one that stops secondary addresses leaking across switches — under test without needing a Windows box. The editor requires the session token in a header for mutations, not just the cookie: any page in the browser can make it POST to 127.0.0.1 with the cookie attached, but it cannot set a header. The updater refuses to install a release that publishes no SHA256. Not yet done: no group picker for export (the API supports it), no single-instance guard, and internal/server/web/app.css is reconstructed from the description in claude.md rather than the canonical apointless.css. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
96 lines
2.6 KiB
Go
96 lines
2.6 KiB
Go
//go:build windows
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package updater
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import (
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"fmt"
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"os"
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"os/exec"
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"path/filepath"
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"strconv"
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"syscall"
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)
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// swapScript waits for ipswap to exit, replaces the binary, restarts it and
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// deletes itself.
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//
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// A running .exe on Windows is locked against overwriting, so the swap cannot
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// be done by the process being replaced — it has to outlive it. A tiny batch
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// file is the least machinery that does this without shipping a second binary.
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//
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// %1 is the PID to wait for, %2 the freshly downloaded exe, %3 the exe to
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// replace. The tasklist/find pair is the standard "is this PID still alive"
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// idiom; `timeout` rather than `ping -n` keeps it readable.
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const swapScript = `@echo off
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setlocal
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set PID=%~1
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set NEWEXE=%~2
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set TARGET=%~3
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rem Give up after ~30s rather than spinning forever if the old process hangs.
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set /a TRIES=0
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:wait
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tasklist /FI "PID eq %PID%" 2>nul | find "%PID%" >nul
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if errorlevel 1 goto swap
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set /a TRIES+=1
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if %TRIES% GEQ 30 goto giveup
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timeout /t 1 /nobreak >nul
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goto wait
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:swap
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copy /y "%NEWEXE%" "%TARGET%" >nul
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if errorlevel 1 goto giveup
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del /q "%NEWEXE%" >nul 2>&1
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start "" "%TARGET%"
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goto done
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:giveup
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rem Leave the download in place so the user can swap it in by hand.
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exit /b 1
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:done
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endlocal
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rem Delete this script last; cmd tolerates a batch file removing itself.
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del /q "%~f0" >nul 2>&1
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`
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// InstallAndRestart writes the swap helper, launches it detached, and returns.
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// The caller must exit promptly afterwards — the helper is already waiting on
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// this process to go away.
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//
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// This is only ever reached from an explicit click on "Update available": the
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// updater never installs on its own.
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func InstallAndRestart(downloadedExe string) error {
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target, err := os.Executable()
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if err != nil {
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return fmt.Errorf("locating the running executable: %w", err)
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}
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target, err = filepath.Abs(target)
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if err != nil {
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return err
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}
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script := filepath.Join(os.TempDir(), "ipswap-update.cmd")
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if err := os.WriteFile(script, []byte(swapScript), 0o755); err != nil {
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return fmt.Errorf("writing the update helper: %w", err)
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}
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cmd := exec.Command("cmd.exe", "/c", script,
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strconv.Itoa(os.Getpid()), downloadedExe, target)
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// Detach: the helper has to survive this process exiting, and it must not
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// flash a console window while it waits.
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cmd.SysProcAttr = &syscall.SysProcAttr{
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HideWindow: true,
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CreationFlags: windowsCreateNoWindow | windowsDetachedProcess,
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}
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if err := cmd.Start(); err != nil {
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return fmt.Errorf("starting the update helper: %w", err)
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}
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return cmd.Process.Release()
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}
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const (
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windowsDetachedProcess = 0x00000008
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windowsCreateNoWindow = 0x08000000
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)
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