Fix zip files created on Windows being unusable on Linux/MacOS (missing executable bits on directories)

from thejoshwolfe/yazl#59

Author: ijisol

index.js

@@ -83,7 +83,7 @@ class Entry {
     this.isDirectory = isDirectory;
     this.state = Entry.WAITING_FOR_METADATA;
     this.setLastModDate(options.mtime ?? new Date());
-    this.setFileAttributesMode(options.mode ?? (isDirectory ? 0o40775 : 0o100664));
+    this.setFileAttributesMode(options.mode ?? 0o000664, isDirectory);
     if (isDirectory) {
       this.crcAndFileSizeKnown = true;
       this.crc32 = 0;
@@ -139,10 +139,19 @@ class Entry {
   /**
    * @param {number} mode
    */
-  setFileAttributesMode(mode) {
+  setFileAttributesMode(mode, isDirectory) {
     if ((mode & 0xffff) !== mode) {
       throw new Error(`invalid mode. expected: 0 <= ${mode} <= 65535`);
     }
+    if (isDirectory) {
+      // https://github.com/thejoshwolfe/yazl/pull/59
+      // Set executable bit on directories if any other bits are set for that user/group/all
+      // Fixes creating unusable zip files on platforms that do not use an executable bit
+      mode |= ((mode >> 1) | (mode >> 2)) & 0o000111;
+      mode |= 0o040000; // S_IFDIR
+    } else {
+      mode |= 0o100000; // S_IFREG
+    }
     // http://unix.stackexchange.com/questions/14705/the-zip-formats-external-file-attribute/14727#14727
     this.externalFileAttributes = (mode << 16) >>> 0;
   }
@@ -381,7 +390,7 @@ class ZipFile extends EventEmitter {
       }
       entry.uncompressedSize = stats.size;
       if (options.mtime == null) entry.setLastModDate(stats.mtime);
-      if (options.mode == null) entry.setFileAttributesMode(stats.mode);
+      if (options.mode == null) entry.setFileAttributesMode(stats.mode, false);
       entry.setFileDataPumpFunction(() => {
         const readStream = createReadStream(realPath);
         entry.state = Entry.FILE_DATA_IN_PROGRESS;

test/test.js

@@ -87,7 +87,7 @@ const filename = fileURLToPath(import.meta.url);
   zipfile.addBuffer(Buffer.from('buffer'), 'b.txt');
   zipfile.addReadStream(new BufferListStream().append('stream'), 'c.txt');
   zipfile.addEmptyDirectory('d/');
-  zipfile.addEmptyDirectory('e');
+  zipfile.addEmptyDirectory('e', { mode: 0o000644 });
   zipfile.end(function (finalSize) {
     if (finalSize !== -1) throw new Error('finalSize should be unknown');
     zipfile.outputStream.pipe(new BufferListStream(function (err, data) {
@@ -96,9 +96,21 @@ const filename = fileURLToPath(import.meta.url);
         if (err) throw err;
         const entryNames = ['a.txt', 'b.txt', 'c.txt', 'd/', 'e/'];
         zipfile.on('entry', function (entry) {
+          const { fileName } = entry;
           const expectedName = entryNames.shift();
-          if (entry.fileName !== expectedName) {
-            throw new Error(`unexpected entry fileName: ${entry.fileName}, expected: ${expectedName}`);
+          if (fileName !== expectedName) {
+            throw new Error(`unexpected entry fileName: ${fileName}, expected: ${expectedName}`);
+          }
+          const mode = entry.externalFileAttributes >>> 16;
+          if (fileName.endsWith('/')) {
+            if ((mode & 0o040000) === 0) {
+              throw new Error(`directory expected to have S_IFDIR, found ${mode.toString(8)}`);
+            }
+            if ((mode & 0o000111) === 0) {
+              throw new Error(`directory expected to have executable flags, found ${mode.toString(8)}`);
+            }
+          } else if ((mode & 0o100000) === 0) {
+            throw new Error(`file expected to have S_IFREG, found ${mode.toString(8)}`);
           }
         });
         zipfile.on('end', function () {