[linux apps] fix drag-n-drop & opening files

src/linuxrunner.js

@@ -61,6 +61,72 @@ function linuxUser() {
   }
 }
 
+// The names the app owns in its home: the redirected XDG folders and the
+// launcher's own folder. The host home never gets to shadow them.
+const OWNED_HOME_NAMES = new Set([PLWL_DIR])
+
+// The host home's own entries - what the desktop can hand an app (a drop from
+// the file manager, a file picked in a dialog). A link resolving nowhere is
+// not a path anything can be given, so it is skipped too.
+function hostHomeEntries() {
+  const home = os.homedir()
+  let names
+  try {
+    names = fs.readdirSync(home)
+  } catch {
+    return []
+  }
+  return names.filter(name => !OWNED_HOME_NAMES.has(name) && fs.existsSync(path.join(home, name)))
+}
+
+// The launcher's own links are the ones pointing into the relaxed view.
+function isFsRootLink(file) {
+  let target
+  try {
+    target = fs.readlinkSync(file)
+  } catch {
+    return false
+  }
+  return target.startsWith(FS_ROOT + path.sep)
+}
+
+function clearHomeRedirects(root) {
+  const dir = path.join(root, 'home')
+  let names
+  try {
+    names = fs.readdirSync(dir)
+  } catch {
+    return
+  }
+  for (const name of names) {
+    if (!isFsRootLink(path.join(dir, name))) continue
+    try {
+      fs.rmSync(path.join(dir, name), { force: true })
+    } catch {}
+  }
+}
+
+// Relaxed is the one level where the real filesystem is reachable (through
+// FS_ROOT) - and there the app's home is mounted over the real one, so a path
+// the desktop hands over names a folder the app cannot see. A link into that
+// view gives exactly those names back, at their real paths; the app's own
+// entries are never touched. No other level has a view to point at, so the
+// links come off again there - they would only dangle.
+function syncHomeRedirects(root, { relaxed }) {
+  clearHomeRedirects(root)
+  if (!relaxed) return []
+  const made = []
+  for (const name of hostHomeEntries()) {
+    const file = path.join(root, 'home', name)
+    if (fs.existsSync(file)) continue
+    try {
+      fs.symlinkSync(path.join(FS_ROOT, os.homedir(), name), file)
+      made.push(name)
+    } catch {}
+  }
+  return made
+}
+
 function copyFromHost(src, dst, { refresh = false } = {}) {
   try {
     if (!refresh && fs.existsSync(dst)) return false
@@ -350,6 +416,7 @@ function buildLinuxEnv({ game, backend = 'env', fsRoot = false }) {
   const prefixName = prefixNameForGame(game)
   const root = ensureLinuxPfx(prefixName)
   syncDesktopConfig(root)
+  const homeRedirects = syncHomeRedirects(root, { relaxed: backend === 'bwrap' && fsRoot })
   const sandboxed = backend === 'bwrap'
   const home = sandboxed ? `/home/${linuxUser()}` : path.join(root, 'home')
   const env = { ...process.env }
@@ -367,7 +434,7 @@ function buildLinuxEnv({ game, backend = 'env', fsRoot = false }) {
   // the app's own environment comes last: it overrides everything above
   for (const [k, v] of Object.entries(game.env || {})) env[k] = v
   // an opened link or document leaves for the host desktop (see openrelay.js)
-  return { env, root, home, prefixName, prefixDir: prefixPath(prefixName), routing: urlRouting({ root, home, sandboxed, fsRoot }) }
+  return { env, root, home, prefixName, prefixDir: prefixPath(prefixName), homeRedirects, routing: urlRouting({ root, home, sandboxed, fsRoot }) }
 }
 
 // Where a handed document goes inside the app's own home - a live bind, so a
@@ -475,12 +542,13 @@ async function runLinuxGame({ game, sandbox, onExit, openFile, handoff = false,
 
   const exe = game.exePath
   const workdir = game.workdir || path.dirname(exe)
-  const { env, root, home, routing } = buildLinuxEnv({ game, backend: chosen.backend, fsRoot: chosen.level === 'relaxed' })
+  const { env, root, home, homeRedirects, routing } = buildLinuxEnv({ game, backend: chosen.backend, fsRoot: chosen.level === 'relaxed' })
   const argList = parseArgs(game.args)
   const handed = await handedPathFor({ openFile, level: chosen.level, root, home, onProgress })
   if (handed) argList.push(handed)
 
   const header = [isolationLine(chosen)]
+  if (homeRedirects.length) header.push(`[plwl] home redirects: ${homeRedirects.length} entries through ${FS_ROOT}`)
   if (game.forceX11) header.push('[plwl] x11 forced (XWayland)')
 
   let cmd = exe
@@ -497,6 +565,9 @@ async function runLinuxGame({ game, sandbox, onExit, openFile, handoff = false,
 
 module.exports = {
   DESKTOP_SEEDS,
+  hostHomeEntries,
+  syncHomeRedirects,
+  clearHomeRedirects,
   HANDOFF_DIR,
   STAGE_NOTICE_BYTES,
   SHIM_REL,