Implement self-update recovery (T-403)

app-win7/platform/windows/selfupdate_windows.go

@@ -0,0 +1,88 @@
+//go:build windows
+
+package windows
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"golang.org/x/sys/windows"
+	"softbox.local/core/updater"
+)
+
+func (platform) WaitForProcessExit(ctx context.Context, pid int, timeout time.Duration) error {
+	return waitForProcessExit(ctx, pid, timeout, openWindowsProcess)
+}
+
+func (platform) StartSelfUpdate(command updater.StartCommand) (int, error) {
+	if !filepath.IsAbs(command.Entrypoint) || !filepath.IsAbs(command.WorkingDirectory) {
+		return 0, fmt.Errorf("self-update launch paths must be absolute")
+	}
+	if filepath.Base(command.Entrypoint) != updater.ProductExecutableName ||
+		filepath.Dir(command.Entrypoint) != filepath.Clean(command.WorkingDirectory) ||
+		command.HealthRequestID == "" {
+		return 0, fmt.Errorf("invalid fixed self-update launch command")
+	}
+	commandLine := exec.Command(command.Entrypoint, updater.InternalHealthFlag, command.HealthRequestID)
+	commandLine.Dir = command.WorkingDirectory
+	if err := commandLine.Start(); err != nil {
+		return 0, err
+	}
+	return commandLine.Process.Pid, nil
+}
+
+func (platform) SyncDirectory(path string) error {
+	pathPointer, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return fmt.Errorf("encode directory path: %w", err)
+	}
+	handle, err := syscall.CreateFile(pathPointer, syscall.GENERIC_READ|syscall.GENERIC_WRITE,
+		syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE, nil,
+		syscall.OPEN_EXISTING, syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
+	if err != nil {
+		return fmt.Errorf("open directory handle: %w", err)
+	}
+	if err := syscall.FlushFileBuffers(handle); err != nil {
+		_ = syscall.CloseHandle(handle)
+		return fmt.Errorf("flush directory handle: %w", err)
+	}
+	if err := syscall.CloseHandle(handle); err != nil {
+		return fmt.Errorf("close directory handle: %w", err)
+	}
+	return nil
+}
+
+type windowsPIDHandle struct{ handle windows.Handle }
+
+func openWindowsProcess(pid int) (pidWaitHandle, error) {
+	handle, err := windows.OpenProcess(windows.SYNCHRONIZE, false, uint32(pid))
+	if err != nil {
+		return nil, err
+	}
+	return windowsPIDHandle{handle: handle}, nil
+}
+
+func (handle windowsPIDHandle) Wait(timeout time.Duration) (bool, error) {
+	milliseconds := uint32(timeout / time.Millisecond)
+	if milliseconds == 0 {
+		milliseconds = 1
+	}
+	result, err := windows.WaitForSingleObject(handle.handle, milliseconds)
+	if err != nil {
+		return false, err
+	}
+	switch result {
+	case windows.WAIT_OBJECT_0:
+		return true, nil
+	case uint32(windows.WAIT_TIMEOUT):
+		return false, nil
+	default:
+		return false, fmt.Errorf("WaitForSingleObject returned %d", result)
+	}
+}
+
+func (handle windowsPIDHandle) Close() error { return windows.CloseHandle(handle.handle) }