[EXPERIMENTAL] linux apps support

src/fsutil.js

@@ -161,6 +161,44 @@ async function copyTree(src, dst, onProgress) {
   return { done, bytes }
 }
 
+// Imported trees come from media that lose permissions (archives, FAT, a
+// read-only backup drive), and copyFile keeps whatever the source had: every
+// node gets owner rwx and `x` mirrored from `r`, so the app can run its own
+// binaries and write its own files.
+async function chmodTree(root) {
+  const desired = mode => mode | 0o700 | ((mode & 0o444) >> 2)
+  let files = 0
+  let dirs = 0
+  const walk = async dir => {
+    let entries
+    try {
+      entries = await fsp.readdir(dir, { withFileTypes: true })
+    } catch {
+      return
+    }
+    for (const entry of entries) {
+      const full = path.join(dir, entry.name)
+      if (entry.isSymbolicLink()) continue
+      if (entry.isDirectory()) {
+        await walk(full)
+      } else if (!entry.isFile()) {
+        continue
+      }
+      try {
+        const before = (await fsp.stat(full)).mode & 0o7777
+        const after = desired(before)
+        if (after !== before) {
+          await fsp.chmod(full, after)
+          if (entry.isDirectory()) dirs++
+          else files++
+        }
+      } catch {}
+    }
+  }
+  await walk(root)
+  return { files, dirs }
+}
+
 // Delete deepest-first with progress through onProgress; symlinks are
 // unlinked, never followed.
 async function removeTree(root, onProgress) {
@@ -228,5 +266,5 @@ async function removeTree(root, onProgress) {
   return { files, dirs, bytes }
 }
 
-module.exports = { pathExists, dedupeDir, copyTree, treeSize, removeTree, progressGate, mapLimit }
+module.exports = { pathExists, dedupeDir, copyTree, treeSize, removeTree, chmodTree, progressGate, mapLimit }