Bug 1673019 - Get and set file permissions in IOUtils r=emalysz

Differential Revision: https://phabricator.services.mozilla.com/D97689

dom/chrome-webidl/IOUtils.webidl

@@ -155,6 +155,22 @@ namespace IOUtils {
    *         DOMException.
    */
   Promise<sequence<DOMString>> getChildren(DOMString path);
+  /**
+   * Set the permissions of the file at |path|.
+   *
+   * Windows does not make a distinction between user, group, and other
+   * permissions like UNICES do. If a permission flag is set for any of user,
+   * group, or other has a permission, then all users will have that
+   * permission. Additionally, Windows does not support setting the
+   * "executable" permission.
+   *
+   * @param path        An absolute file path
+   * @param permissions The UNIX file mode representing the permissions.
+   *
+   * @return Resolves if the permissions were set successfully, otherwise
+   *         rejects with a DOMException.
+   */
+  Promise<void> setPermissions(DOMString path, unsigned long permissions);
 };
 
 /**
@@ -305,4 +321,12 @@ dictionary FileInfo {
    * This is only available on MacOS and Windows.
    */
   long long creationTime;
+  /**
+   * The permissions of the file, expressed as a UNIX file mode.
+   *
+   * NB: Windows does not make a distinction between user, group, and other
+   * permissions like UNICES do. The user, group, and other parts will always
+   * be identical on Windows.
+   */
+  unsigned long permissions;
 };

dom/system/IOUtils.cpp

@@ -131,6 +131,9 @@ MOZ_MUST_USE inline bool ToJSValue(
   if (aInternalFileInfo.mCreationTime.isSome()) {
     info.mCreationTime.Construct(aInternalFileInfo.mCreationTime.ref());
   }
+
+  info.mPermissions.Construct(aInternalFileInfo.mPermissions);
+
   return ToJSValue(aCx, info, aValue);
 }
 
@@ -456,6 +459,25 @@ already_AddRefed<Promise> IOUtils::GetChildren(GlobalObject& aGlobal,
   return promise.forget();
 }
 
+/* static */
+already_AddRefed<Promise> IOUtils::SetPermissions(GlobalObject& aGlobal,
+                                                  const nsAString& aPath,
+                                                  const uint32_t aPermissions) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  RefPtr<Promise> promise = CreateJSPromise(aGlobal);
+  NS_ENSURE_TRUE(!!promise, nullptr);
+
+  nsCOMPtr<nsIFile> file = new nsLocalFile();
+  REJECT_IF_INIT_PATH_FAILED(file, aPath, promise);
+
+  RunOnBackgroundThread<Ok>(
+      promise, [file = std::move(file), permissions = aPermissions]() {
+        return SetPermissionsSync(file, permissions);
+      });
+
+  return promise.forget();
+}
+
 /* static */
 already_AddRefed<nsISerialEventTarget> IOUtils::GetBackgroundEventTarget() {
   if (sShutdownStarted) {
@@ -1117,6 +1139,8 @@ Result<IOUtils::InternalFileInfo, IOUtils::IOError> IOUtils::StatSync(
     return Err(IOError(rv));
   }
 
+  MOZ_TRY(aFile->GetPermissions(&info.mPermissions));
+
   return info;
 }
 
@@ -1205,6 +1229,15 @@ Result<nsTArray<nsString>, IOUtils::IOError> IOUtils::GetChildrenSync(
   return children;
 }
 
+/* static */
+Result<Ok, IOUtils::IOError> IOUtils::SetPermissionsSync(
+    nsIFile* aFile, const uint32_t aPermissions) {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  MOZ_TRY(aFile->SetPermissions(aPermissions));
+  return Ok{};
+}
+
 /* static */
 Result<nsTArray<uint8_t>, IOUtils::IOError> IOUtils::MozLZ4::Compress(
     Span<const uint8_t> aUncompressed) {

dom/system/IOUtils.h

@@ -99,6 +99,10 @@ class IOUtils final {
   static already_AddRefed<Promise> GetChildren(GlobalObject& aGlobal,
                                                const nsAString& aPath);
 
+  static already_AddRefed<Promise> SetPermissions(GlobalObject& aGlobal,
+                                                  const nsAString& aPath,
+                                                  const uint32_t aPermissions);
+
   static bool IsAbsolutePath(const nsAString& aPath);
 
  private:
@@ -326,6 +330,22 @@ class IOUtils final {
    *         If there are no children, an empty array. Otherwise, an error.
    */
   static Result<nsTArray<nsString>, IOError> GetChildrenSync(nsIFile* aFile);
+
+  /**
+   * Set the permissions of the given file.
+   *
+   * Windows does not make a distinction between user, group, and other
+   * permissions like UNICES do. If a permission flag is set for any of user,
+   * group, or other has a permission, then all users will have that
+   * permission.
+   *
+   * @param aFile        The location of the file.
+   * @param aPermissions The permissions to set, as a UNIX file mode.
+   *
+   * @return |Ok| if the permissions were successfully set, or an error.
+   */
+  static Result<Ok, IOError> SetPermissionsSync(nsIFile* aFile,
+                                                const uint32_t aPermissions);
 };
 
 /**
@@ -382,6 +402,7 @@ struct IOUtils::InternalFileInfo {
   uint64_t mSize;
   uint64_t mLastModified;
   Maybe<uint64_t> mCreationTime;
+  uint32_t mPermissions;
 };
 
 /**

dom/system/tests/ioutils/chrome.ini

@@ -12,3 +12,4 @@ support-files =
 [test_ioutils_remove.html]
 [test_ioutils_stat_touch.html]
 [test_ioutils_worker.xhtml]
+[test_ioutils_set_permissions.html]

dom/system/tests/ioutils/test_ioutils_set_permissions.html

@@ -0,0 +1,53 @@
+<!-- Any copyright is dedicated to the Public Domain.
+- http://creativecommons.org/publicdomain/zero/1.0/ -->
+<!DOCTYPE HTML>
+<html>
+
+<head>
+  <meta charset="utf-8">
+  <title>Test the IOUtils file I/O API</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+  <script src="file_ioutils_test_fixtures.js"></script>
+  <script>
+    "use strict";
+
+    const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+    add_task(async function test_setPermissions() {
+      const tempDir = await PathUtils.getTempDir();
+      const tempFile = PathUtils.join(tempDir, "setPermissions.tmp");
+
+      await IOUtils.writeAtomicUTF8(tempFile, "");
+      await IOUtils.setPermissions(tempFile, 0o421);
+
+      let stat = await IOUtils.stat(tempFile);
+
+      if (Services.appinfo.OS === "WINNT") {
+        // setPermissions ignores the x bit on Windows.
+        is(stat.permissions, 0o666, "Permissions munged on Windows");
+      } else {
+        is(stat.permissions, 0o421, "Permissions match");
+      }
+
+      await IOUtils.setPermissions(tempFile, 0o400);
+      stat = await IOUtils.stat(tempFile);
+
+      if (Services.appinfo.OS === "WINNT") {
+        is(stat.permissions, 0o444, "Permissions munged on Windows");
+      } else {
+        is(stat.permissions, 0o400, "Permissions match");
+
+        await cleanup(tempFile);
+      }
+    });
+  </script>
+</head>
+
+<body>
+  <p id="display"></p>
+  <div id="content" style="display: none"></div>
+  <pre id="test"></pre>
+</body>
+
+</html>