Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

13 files changed, 1864 insertions, 0 deletions

diff --git a/toolkit/components/taskscheduler/TaskScheduler.jsm b/toolkit/components/taskscheduler/TaskScheduler.jsm
new file mode 100644
index 0000000000..de3ba7cb29
--- /dev/null
+++ b/toolkit/components/taskscheduler/TaskScheduler.jsm
@@ -0,0 +1,160 @@
+/* -*- js-indent-level: 2; indent-tabs-mode: nil -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["TaskScheduler"];
+
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  WinImpl: "resource://gre/modules/TaskSchedulerWinImpl.jsm",
+  MacOSImpl: "resource://gre/modules/TaskSchedulerMacOSImpl.jsm",
+});
+
+XPCOMUtils.defineLazyGetter(lazy, "gImpl", () => {
+  if (AppConstants.platform == "win") {
+    return lazy.WinImpl;
+  }
+
+  if (AppConstants.platform == "macosx") {
+    return lazy.MacOSImpl;
+  }
+
+  // Stubs for unsupported platforms
+  return {
+    registerTask() {},
+    deleteTask() {},
+    deleteAllTasks() {},
+  };
+});
+
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+/**
+ * Interface to a system task scheduler, capable of running a command line at an interval
+ * independent of the application.
+ *
+ * The expected consumer of this component wants to run a periodic short-lived maintenance task.
+ * These periodic maintenance tasks will be per-OS-level user and run with the OS-level user's
+ * permissions.  (These still need to work across systems with multiple users and the various
+ * ownership and permission combinations that we see.)  This component does not help schedule
+ * maintenance daemons, meaning long-lived processes.
+ *
+ * Currently only implemented for Windows and macOS, on other platforms these calls do nothing.
+ *
+ * The implementation will only interact with tasks from the same install of this application.
+ * - On Windows the native tasks are named like "\<vendor>\<id> <install path hash>",
+ *   e.g. "\Mozilla\Task Identifier 308046B0AF4A39CB"
+ * - On macOS the native tasks are labeled like "<macOS bundle ID>.<install path hash>.<id>",
+ *   e.g. "org.mozilla.nightly.308046B0AF4A39CB.Task Identifier".
+ */
+var TaskScheduler = {
+  MIN_INTERVAL_SECONDS: 1800,
+
+  /**
+   * Create a scheduled task that will run a command indepedent of the application.
+   *
+   * It will run every intervalSeconds seconds, starting intervalSeconds seconds from now.
+   *
+   * If the task is unable to run one or more scheduled times (e.g. if the computer is
+   * off, or the owning user is not logged in), then the next time a run is possible the task
+   * will be run once.
+   *
+   * An existing task with the same `id` will be replaced.
+   *
+   * Only one instance of the task will run at once, though this does not affect different
+   * tasks from the same application.
+   *
+   * @param id
+   *        A unique string (including a UUID is recommended) to distinguish the task among
+   *        other tasks from this installation.
+   *        This string will also be visible to system administrators, so it should be a legible
+   *        description, but it does not need to be localized.
+   *
+   * @param command
+   *        Full path to the executable to run.
+   *
+   * @param intervalSeconds
+   *        Interval at which to run the command, in seconds. Minimum 1800 (30 minutes).
+   *
+   * @param options
+   *        Optional, as are all of its properties:
+   *        {
+   *          args
+   *            Array of arguments to pass on the command line. Does not include the command
+   *            itself even if that is considered part of the command line. If missing, no
+   *            argument list is generated.
+   *
+   *          workingDirectory
+   *            Working directory for the command. If missing, no working directory is set.
+   *
+   *          description
+   *            A description string that will be visible to system administrators. This should
+   *            be localized. If missing, no description is set.
+   *
+   *          disabled
+   *            If true the task will be created disabled, so that it will not be run.
+   *            Ignored on macOS: see comments in TaskSchedulerMacOSImpl.jsm.
+   *            Default false, intended for tests.
+   *
+   *          executionTimeoutSec
+   *            Specifies how long (in seconds) the scheduled task can execute for before it is
+   *            automatically stopped by the task scheduler. If a value <= 0 is given, it will be
+   *            ignored.
+   *            This is not currently implemented on macOS.
+   *            On Windows, the default timeout is 72 hours.
+   *        }
+   * }
+   */
+  async registerTask(id, command, intervalSeconds, options) {
+    if (typeof id !== "string") {
+      throw new Error("id is not a string");
+    }
+    if (!Number.isInteger(intervalSeconds)) {
+      throw new Error("Interval is not an integer");
+    }
+    if (intervalSeconds < this.MIN_INTERVAL_SECONDS) {
+      throw new Error("Interval is too short");
+    }
+
+    return lazy.gImpl.registerTask(id, command, intervalSeconds, options);
+  },
+
+  /**
+   * Delete a scheduled task previously created with registerTask.
+   *
+   * @throws NS_ERROR_FILE_NOT_FOUND if the task does not exist.
+   */
+  async deleteTask(id) {
+    return lazy.gImpl.deleteTask(id);
+  },
+
+  /**
+   * Delete all tasks registered by this application.
+   */
+  async deleteAllTasks() {
+    return lazy.gImpl.deleteAllTasks();
+  },
+
+  /**
+   * Checks if a task exists.
+   *
+   * @param id
+   *        A string representing the identifier of the task to look for.
+   *
+   * @return
+   *        true if the task exists, otherwise false.
+   */
+  async taskExists(id) {
+    return lazy.gImpl.taskExists(id);
+  },
+};
diff --git a/toolkit/components/taskscheduler/TaskSchedulerMacOSImpl.jsm b/toolkit/components/taskscheduler/TaskSchedulerMacOSImpl.jsm
new file mode 100644
index 0000000000..3f942d1ae5
--- /dev/null
+++ b/toolkit/components/taskscheduler/TaskSchedulerMacOSImpl.jsm
@@ -0,0 +1,359 @@
+/* -*- js-indent-level: 2; indent-tabs-mode: nil -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["MacOSImpl"];
+
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Subprocess: "resource://gre/modules/Subprocess.sys.mjs",
+});
+
+XPCOMUtils.defineLazyServiceGetters(lazy, {
+  XreDirProvider: [
+    "@mozilla.org/xre/directory-provider;1",
+    "nsIXREDirProvider",
+  ],
+});
+
+XPCOMUtils.defineLazyGetter(lazy, "log", () => {
+  let { ConsoleAPI } = ChromeUtils.importESModule(
+    "resource://gre/modules/Console.sys.mjs"
+  );
+  let consoleOptions = {
+    // tip: set maxLogLevel to "debug" and use log.debug() to create detailed
+    // messages during development. See LOG_LEVELS in Console.sys.mjs for details.
+    maxLogLevel: "error",
+    maxLogLevelPref: "toolkit.components.taskscheduler.loglevel",
+    prefix: "TaskScheduler",
+  };
+  return new ConsoleAPI(consoleOptions);
+});
+
+/**
+ * Task generation and management for macOS, using `launchd` via `launchctl`.
+ *
+ * Implements the API exposed in TaskScheduler.jsm
+ * Not intended for external use, this is in a separate module to ship the code only
+ * on macOS, and to expose for testing.
+ */
+var MacOSImpl = {
+  async registerTask(id, command, intervalSeconds, options) {
+    lazy.log.info(
+      `registerTask(${id}, ${command}, ${intervalSeconds}, ${JSON.stringify(
+        options
+      )})`
+    );
+
+    let uid = await this._uid();
+    lazy.log.debug(`registerTask: uid=${uid}`);
+
+    let label = this._formatLabelForThisApp(id);
+
+    // We ignore `options.disabled`, which is test only.
+    //
+    // The `Disabled` key prevents `launchd` from registering the task, with
+    // exit code 133 and error message "Service is disabled".  If we really want
+    // this flow in the future, there is `launchctl disable ...`, but it's
+    // fraught with peril: the disabled status is stored outside of any plist,
+    // and it persists even after the task is deleted.  Monkeying with the
+    // disabled status will likely prevent users from disabling these tasks
+    // forcibly, should it come to that.  All told, fraught.
+    //
+    // For the future: there is the `RunAtLoad` key, should we want to run the
+    // task once immediately.
+    let plist = {};
+    plist.Label = label;
+    plist.ProgramArguments = [command];
+    if (options.args) {
+      plist.ProgramArguments.push(...options.args);
+    }
+    plist.StartInterval = intervalSeconds;
+    if (options.workingDirectory) {
+      plist.WorkingDirectory = options.workingDirectory;
+    }
+
+    let str = this._formatLaunchdPlist(plist);
+    let path = this._formatPlistPath(label);
+
+    await IOUtils.write(path, new TextEncoder().encode(str));
+    lazy.log.debug(`registerTask: wrote ${path}`);
+
+    try {
+      let bootout = await lazy.Subprocess.call({
+        command: "/bin/launchctl",
+        arguments: ["bootout", `gui/${uid}/${label}`],
+        stderr: "stdout",
+      });
+
+      lazy.log.debug(
+        "registerTask: bootout stdout",
+        await bootout.stdout.readString()
+      );
+
+      let { exitCode } = await bootout.wait();
+      lazy.log.debug(`registerTask: bootout returned ${exitCode}`);
+
+      let bootstrap = await lazy.Subprocess.call({
+        command: "/bin/launchctl",
+        arguments: ["bootstrap", `gui/${uid}`, path],
+        stderr: "stdout",
+      });
+
+      lazy.log.debug(
+        "registerTask: bootstrap stdout",
+        await bootstrap.stdout.readString()
+      );
+
+      ({ exitCode } = await bootstrap.wait());
+      lazy.log.debug(`registerTask: bootstrap returned ${exitCode}`);
+
+      if (exitCode != 0) {
+        throw new Components.Exception(
+          `Failed to run launchctl bootstrap: ${exitCode}`,
+          Cr.NS_ERROR_UNEXPECTED
+        );
+      }
+    } catch (e) {
+      // Try to clean up.
+      await IOUtils.remove(path, { ignoreAbsent: true });
+      throw e;
+    }
+
+    return true;
+  },
+
+  async deleteTask(id) {
+    lazy.log.info(`deleteTask(${id})`);
+
+    let label = this._formatLabelForThisApp(id);
+    return this._deleteTaskByLabel(label);
+  },
+
+  async _deleteTaskByLabel(label) {
+    let path = this._formatPlistPath(label);
+    lazy.log.debug(`_deleteTaskByLabel: removing ${path}`);
+    await IOUtils.remove(path, { ignoreAbsent: true });
+
+    let uid = await this._uid();
+    lazy.log.debug(`_deleteTaskByLabel: uid=${uid}`);
+
+    let bootout = await lazy.Subprocess.call({
+      command: "/bin/launchctl",
+      arguments: ["bootout", `gui/${uid}/${label}`],
+      stderr: "stdout",
+    });
+
+    let { exitCode } = await bootout.wait();
+    lazy.log.debug(`_deleteTaskByLabel: bootout returned ${exitCode}`);
+    lazy.log.debug(
+      `_deleteTaskByLabel: bootout stdout`,
+      await bootout.stdout.readString()
+    );
+
+    return !exitCode;
+  },
+
+  // For internal and testing use only.
+  async _listAllLabelsForThisApp() {
+    let proc = await lazy.Subprocess.call({
+      command: "/bin/launchctl",
+      arguments: ["list"],
+      stderr: "stdout",
+    });
+
+    let { exitCode } = await proc.wait();
+    if (exitCode != 0) {
+      throw new Components.Exception(
+        `Failed to run /bin/launchctl list: ${exitCode}`,
+        Cr.NS_ERROR_UNEXPECTED
+      );
+    }
+
+    let stdout = await proc.stdout.readString();
+
+    let lines = stdout.split(/\r\n|\n|\r/);
+    let labels = lines
+      .map(line => line.split("\t").pop()) // Lines are like "-\t0\tlabel".
+      .filter(this._labelMatchesThisApp);
+
+    lazy.log.debug(`_listAllLabelsForThisApp`, labels);
+    return labels;
+  },
+
+  async deleteAllTasks() {
+    lazy.log.info(`deleteAllTasks()`);
+
+    let labelsToDelete = await this._listAllLabelsForThisApp();
+
+    let deleted = 0;
+    let failed = 0;
+    for (const label of labelsToDelete) {
+      try {
+        if (await this._deleteTaskByLabel(label)) {
+          deleted += 1;
+        } else {
+          failed += 1;
+        }
+      } catch (e) {
+        failed += 1;
+      }
+    }
+
+    let result = { deleted, failed };
+    lazy.log.debug(`deleteAllTasks: returning ${JSON.stringify(result)}`);
+  },
+
+  async taskExists(id) {
+    const label = this._formatLabelForThisApp(id);
+    const path = this._formatPlistPath(label);
+    return IOUtils.exists(path);
+  },
+
+  /**
+   * Turn an object into a macOS plist.
+   *
+   * Properties of type array-of-string, dict-of-string, string,
+   * number, and boolean are supported.
+   *
+   * @param   options object to turn into macOS plist.
+   * @returns plist as an XML DOM object.
+   */
+  _toLaunchdPlist(options) {
+    const doc = new DOMParser().parseFromString("<plist></plist>", "text/xml");
+    const root = doc.documentElement;
+    root.setAttribute("version", "1.0");
+
+    let dict = doc.createElement("dict");
+    root.appendChild(dict);
+
+    for (let [k, v] of Object.entries(options)) {
+      let key = doc.createElement("key");
+      key.textContent = k;
+      dict.appendChild(key);
+
+      if (Array.isArray(v)) {
+        let array = doc.createElement("array");
+        dict.appendChild(array);
+
+        for (let vv of v) {
+          let string = doc.createElement("string");
+          string.textContent = vv;
+          array.appendChild(string);
+        }
+      } else if (typeof v === "object") {
+        let d = doc.createElement("dict");
+        dict.appendChild(d);
+
+        for (let [kk, vv] of Object.entries(v)) {
+          key = doc.createElement("key");
+          key.textContent = kk;
+          d.appendChild(key);
+
+          let string = doc.createElement("string");
+          string.textContent = vv;
+          d.appendChild(string);
+        }
+      } else if (typeof v === "number") {
+        let number = doc.createElement(
+          Number.isInteger(v) ? "integer" : "real"
+        );
+        number.textContent = v;
+        dict.appendChild(number);
+      } else if (typeof v === "string") {
+        let string = doc.createElement("string");
+        string.textContent = v;
+        dict.appendChild(string);
+      } else if (typeof v === "boolean") {
+        let bool = doc.createElement(v ? "true" : "false");
+        dict.appendChild(bool);
+      }
+    }
+
+    return doc;
+  },
+
+  /**
+   * Turn an object into a macOS plist encoded as a string.
+   *
+   * Properties of type array-of-string, dict-of-string, string,
+   * number, and boolean are supported.
+   *
+   * @param   options object to turn into macOS plist.
+   * @returns plist as a string.
+   */
+  _formatLaunchdPlist(options) {
+    let doc = this._toLaunchdPlist(options);
+
+    let serializer = new XMLSerializer();
+    return serializer.serializeToString(doc);
+  },
+
+  _formatLabelForThisApp(id) {
+    let installHash = lazy.XreDirProvider.getInstallHash();
+    return `${AppConstants.MOZ_MACBUNDLE_ID}.${installHash}.${id}`;
+  },
+
+  _labelMatchesThisApp(label) {
+    let installHash = lazy.XreDirProvider.getInstallHash();
+    return (
+      label &&
+      label.startsWith(`${AppConstants.MOZ_MACBUNDLE_ID}.${installHash}.`)
+    );
+  },
+
+  _formatPlistPath(label) {
+    let file = Services.dirsvc.get("Home", Ci.nsIFile);
+    file.append("Library");
+    file.append("LaunchAgents");
+    file.append(`${label}.plist`);
+    return file.path;
+  },
+
+  _cachedUid: -1,
+
+  async _uid() {
+    if (this._cachedUid >= 0) {
+      return this._cachedUid;
+    }
+
+    // There are standard APIs for determining our current UID, but this
+    // is easy and parallel to the general tactics used by this module.
+    let proc = await lazy.Subprocess.call({
+      command: "/usr/bin/id",
+      arguments: ["-u"],
+      stderr: "stdout",
+    });
+
+    let stdout = await proc.stdout.readString();
+
+    let { exitCode } = await proc.wait();
+    if (exitCode != 0) {
+      throw new Components.Exception(
+        `Failed to run /usr/bin/id: ${exitCode}`,
+        Cr.NS_ERROR_UNEXPECTED
+      );
+    }
+
+    try {
+      this._cachedUid = Number.parseInt(stdout);
+      return this._cachedUid;
+    } catch (e) {
+      throw new Components.Exception(
+        `Failed to parse /usr/bin/id output as integer: ${stdout}`,
+        Cr.NS_ERROR_UNEXPECTED
+      );
+    }
+  },
+};
diff --git a/toolkit/components/taskscheduler/TaskSchedulerWinImpl.jsm b/toolkit/components/taskscheduler/TaskSchedulerWinImpl.jsm
new file mode 100644
index 0000000000..256dabbcfd
--- /dev/null
+++ b/toolkit/components/taskscheduler/TaskSchedulerWinImpl.jsm
@@ -0,0 +1,291 @@
+/* -*- js-indent-level: 2; indent-tabs-mode: nil -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["WinImpl"];
+
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+const lazy = {};
+
+XPCOMUtils.defineLazyServiceGetters(lazy, {
+  WinTaskSvc: [
+    "@mozilla.org/win-task-scheduler-service;1",
+    "nsIWinTaskSchedulerService",
+  ],
+  XreDirProvider: [
+    "@mozilla.org/xre/directory-provider;1",
+    "nsIXREDirProvider",
+  ],
+});
+
+/**
+ * Task generation and management for Windows, using Task Scheduler 2.0 (taskschd).
+ *
+ * Implements the API exposed in TaskScheduler.jsm
+ * Not intended for external use, this is in a separate module to ship the code only
+ * on Windows, and to expose for testing.
+ */
+var WinImpl = {
+  registerTask(id, command, intervalSeconds, options) {
+    // The folder might not yet exist.
+    this._createFolderIfNonexistent();
+
+    const xml = this._formatTaskDefinitionXML(
+      command,
+      intervalSeconds,
+      options
+    );
+    const updateExisting = true;
+
+    lazy.WinTaskSvc.registerTask(
+      this._taskFolderName(),
+      this._formatTaskName(id),
+      xml,
+      updateExisting
+    );
+  },
+
+  deleteTask(id) {
+    lazy.WinTaskSvc.deleteTask(
+      this._taskFolderName(),
+      this._formatTaskName(id)
+    );
+  },
+
+  /**
+   * Delete all tasks created by this installation.
+   *
+   * The Windows Default Browser Agent task is special: it's
+   * registered by the installer and might run as a different user and
+   * require permissions to delete.  We ignore it and leave it for the
+   * uninstaller to remove.
+   */
+  deleteAllTasks() {
+    const taskFolderName = this._taskFolderName();
+
+    let allTasks;
+    try {
+      allTasks = lazy.WinTaskSvc.getFolderTasks(taskFolderName);
+    } catch (ex) {
+      if (ex.result == Cr.NS_ERROR_FILE_NOT_FOUND) {
+        // Folder doesn't exist, nothing to delete.
+        return;
+      }
+      throw ex;
+    }
+
+    const tasksToDelete = allTasks.filter(name => this._matchAppTaskName(name));
+
+    let numberDeleted = 0;
+    let lastFailedTaskName;
+    // We need `MOZ_APP_DISPLAYNAME` since that's what the WDBA (written in C++) uses.
+    const defaultBrowserAgentTaskName =
+      AppConstants.MOZ_APP_DISPLAYNAME_DO_NOT_USE +
+      " Default Browser Agent " +
+      lazy.XreDirProvider.getInstallHash();
+    for (const taskName of tasksToDelete) {
+      if (taskName == defaultBrowserAgentTaskName) {
+        // Skip the Windows Default Browser Agent task.
+        continue;
+      }
+
+      try {
+        lazy.WinTaskSvc.deleteTask(taskFolderName, taskName);
+        numberDeleted += 1;
+      } catch (e) {
+        lastFailedTaskName = taskName;
+      }
+    }
+
+    if (lastFailedTaskName) {
+      // There's no standard way to chain exceptions, so instead try again,
+      // which should fail and throw again.  It's possible this isn't idempotent
+      // but we're expecting failures to be due to permission errors, which are
+      // likely to be static.
+      lazy.WinTaskSvc.deleteTask(taskFolderName, lastFailedTaskName);
+    }
+
+    if (allTasks.length == numberDeleted) {
+      // Deleted every task, remove the folder.
+      this._deleteFolderIfEmpty();
+    }
+  },
+
+  taskExists(id) {
+    const taskFolderName = this._taskFolderName();
+
+    let allTasks;
+    try {
+      allTasks = lazy.WinTaskSvc.getFolderTasks(taskFolderName);
+    } catch (ex) {
+      if (ex.result == Cr.NS_ERROR_FILE_NOT_FOUND) {
+        // Folder doesn't exist, so neither do tasks within it.
+        return false;
+      }
+      throw ex;
+    }
+
+    return allTasks.includes(this._formatTaskName(id));
+  },
+
+  _formatTaskDefinitionXML(command, intervalSeconds, options) {
+    const startTime = new Date(Date.now() + intervalSeconds * 1000);
+    const xmlns = "http://schemas.microsoft.com/windows/2004/02/mit/task";
+
+    // Fill in the constant parts of the task, and those that don't require escaping.
+    const docBase = `<Task xmlns="${xmlns}">
+  <Triggers>
+    <TimeTrigger>
+      <StartBoundary>${startTime.toISOString()}</StartBoundary>
+      <Repetition>
+        <Interval>PT${intervalSeconds}S</Interval>
+      </Repetition>
+    </TimeTrigger>
+  </Triggers>
+  <Actions>
+    <Exec />
+  </Actions>
+  <Settings>
+    <StartWhenAvailable>true</StartWhenAvailable>
+    <MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
+  </Settings>
+  <RegistrationInfo>
+     <Author />
+  </RegistrationInfo>
+</Task>`;
+    const doc = new DOMParser().parseFromString(docBase, "text/xml");
+
+    const execAction = doc.querySelector("Actions Exec");
+
+    const settings = doc.querySelector("Settings");
+
+    const commandNode = doc.createElementNS(xmlns, "Command");
+    commandNode.textContent = command;
+    execAction.appendChild(commandNode);
+
+    if (options?.args) {
+      const args = doc.createElementNS(xmlns, "Arguments");
+      args.textContent = options.args.map(this._quoteString).join(" ");
+      execAction.appendChild(args);
+    }
+
+    if (options?.workingDirectory) {
+      const workingDirectory = doc.createElementNS(xmlns, "WorkingDirectory");
+      workingDirectory.textContent = options.workingDirectory;
+      execAction.appendChild(workingDirectory);
+    }
+
+    if (options?.disabled) {
+      const enabled = doc.createElementNS(xmlns, "Enabled");
+      enabled.textContent = "false";
+      settings.appendChild(enabled);
+    }
+
+    if (options?.executionTimeoutSec && options.executionTimeoutSec > 0) {
+      const timeout = doc.createElementNS(xmlns, "ExecutionTimeLimit");
+      timeout.textContent = `PT${options.executionTimeoutSec}S`;
+      settings.appendChild(timeout);
+    }
+
+    // Other settings to consider for the future:
+    // Idle
+    // Battery
+
+    doc.querySelector("RegistrationInfo Author").textContent =
+      Services.appinfo.vendor;
+
+    if (options?.description) {
+      const registrationInfo = doc.querySelector("RegistrationInfo");
+      const description = doc.createElementNS(xmlns, "Description");
+      description.textContent = options.description;
+      registrationInfo.appendChild(description);
+    }
+
+    const serializer = new XMLSerializer();
+    return serializer.serializeToString(doc);
+  },
+
+  _createFolderIfNonexistent() {
+    const { parentName, subName } = this._taskFolderNameParts();
+
+    try {
+      lazy.WinTaskSvc.createFolder(parentName, subName);
+    } catch (e) {
+      if (e.result != Cr.NS_ERROR_FILE_ALREADY_EXISTS) {
+        throw e;
+      }
+    }
+  },
+
+  _deleteFolderIfEmpty() {
+    const { parentName, subName } = this._taskFolderNameParts();
+
+    try {
+      lazy.WinTaskSvc.deleteFolder(parentName, subName);
+    } catch (e) {
+      // Missed one somehow, possibly a subfolder?
+      if (e.result != Cr.NS_ERROR_FILE_DIR_NOT_EMPTY) {
+        throw e;
+      }
+    }
+  },
+
+  /**
+   * Quotes a string for use as a single command argument, using Windows quoting
+   * conventions.
+   *
+   * copied from quoteString() in toolkit/modules/subproces/subprocess_worker_win.js
+   *
+   *
+   * @see https://msdn.microsoft.com/en-us/library/17w5ykft(v=vs.85).aspx
+   *
+   * @param {string} str
+   *        The argument string to quote.
+   * @returns {string}
+   */
+  _quoteString(str) {
+    if (!/[\s"]/.test(str)) {
+      return str;
+    }
+
+    let escaped = str.replace(/(\\*)("|$)/g, (m0, m1, m2) => {
+      if (m2) {
+        m2 = `\\${m2}`;
+      }
+      return `${m1}${m1}${m2}`;
+    });
+
+    return `"${escaped}"`;
+  },
+
+  _taskFolderName() {
+    return `\\${Services.appinfo.vendor}`;
+  },
+
+  _taskFolderNameParts() {
+    return {
+      parentName: "\\",
+      subName: Services.appinfo.vendor,
+    };
+  },
+
+  _formatTaskName(id) {
+    const installHash = lazy.XreDirProvider.getInstallHash();
+    return `${id} ${installHash}`;
+  },
+
+  _matchAppTaskName(name) {
+    const installHash = lazy.XreDirProvider.getInstallHash();
+    return name.endsWith(` ${installHash}`);
+  },
+};
diff --git a/toolkit/components/taskscheduler/components.conf b/toolkit/components/taskscheduler/components.conf
new file mode 100644
index 0000000000..c6e96da1b4
--- /dev/null
+++ b/toolkit/components/taskscheduler/components.conf
@@ -0,0 +1,18 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Classes = []
+
+if buildconfig.substs['OS_TARGET'] == 'WINNT':
+    Classes += [
+        {
+            'cid': '{e2113dfc-8efe-43a1-8a20-ad720dd771d6}',
+            'contract_ids': ['@mozilla.org/win-task-scheduler-service;1'],
+            'type': 'nsWinTaskSchedulerService',
+            'headers': ['nsWinTaskScheduler.h'],
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        },
+    ]
diff --git a/toolkit/components/taskscheduler/moz.build b/toolkit/components/taskscheduler/moz.build
new file mode 100644
index 0000000000..b72c8a9278
--- /dev/null
+++ b/toolkit/components/taskscheduler/moz.build
@@ -0,0 +1,29 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Toolkit", "Application Update")
+
+XPCSHELL_TESTS_MANIFESTS += ["tests/xpcshell/xpcshell.ini"]
+
+EXTRA_JS_MODULES += ["TaskScheduler.jsm"]
+
+# This whole component is currently Windows-only, but a Mac implementation is planned.
+# Only the Windows C++ interface is an XPCOM component.
+if CONFIG["OS_TARGET"] == "WINNT":
+    EXTRA_JS_MODULES += ["TaskSchedulerWinImpl.jsm"]
+    XPCOM_MANIFESTS += ["components.conf"]
+    XPIDL_MODULE = "taskscheduler"
+    XPIDL_SOURCES += ["nsIWinTaskSchedulerService.idl"]
+    EXPORTS += ["nsWinTaskScheduler.h"]
+    SOURCES += ["nsWinTaskScheduler.cpp"]
+    OS_LIBS += ["taskschd"]
+    DEFINES["UNICODE"] = True
+
+if CONFIG["OS_TARGET"] == "Darwin":
+    EXTRA_JS_MODULES += ["TaskSchedulerMacOSImpl.jsm"]
+
+FINAL_LIBRARY = "xul"
diff --git a/toolkit/components/taskscheduler/nsIWinTaskSchedulerService.idl b/toolkit/components/taskscheduler/nsIWinTaskSchedulerService.idl
new file mode 100644
index 0000000000..7a7c5747c0
--- /dev/null
+++ b/toolkit/components/taskscheduler/nsIWinTaskSchedulerService.idl
@@ -0,0 +1,104 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+/**
+ * An interface for Windows Task Scheduler 2.0.
+ * Documentation for the underlying APIs can be found at
+ * https://docs.microsoft.com/en-us/windows/win32/taskschd/task-scheduler-start-page
+ */
+[scriptable, main_process_scriptable_only, uuid(a8d36901-0b6a-46c3-a214-a9e1d5d6047a)]
+interface nsIWinTaskSchedulerService : nsISupports
+{
+  /**
+   * Register (create) a task from an XML definition.
+   * The task will be created so that it only runs as the current user
+   * (TASK_LOGON_INTERACTIVE_TOKEN).
+   *
+   * @throws NS_ERROR_FILE_NOT_FOUND if the folder does not exist.
+   * @throws NS_ERROR_FILE_ALREADY_EXISTS if the task already existed and aUpdateExisting is false.
+   *
+   * @param aFolderName     Full name of the folder in which to create the task, starting with "\".
+   *
+   * @param aTaskName       Name of the task.
+   *
+   * @param aDefinitionXML  XML definition of the task. This is passed directly to Task Scheduler,
+   *                        see the schema at
+   *                        https://docs.microsoft.com/en-us/windows/win32/taskschd/task-scheduler-schema
+   *
+   * @param aUpdateExisting Whether to update an existing task with the same name, default false.
+   */
+  void registerTask(in wstring aFolderName,
+                    in wstring aTaskName,
+                    in wstring aDefinitionXML,
+                    [optional] in boolean aUpdateExisting);
+
+  /**
+   * Validate the XML task definition with Task Scheduler without creating a task, for testing.
+   * Doesn't throw if only the final ITaskFolder::RegisterTask() fails.
+   *
+   * @param aDefinitionXML      Definition to validate.
+   * @return                    HRESULT from ITaskFolder::RegisterTask()
+   *                            Success should be S_OK (0). XML validation failure could be one of
+   *                            SCHED_E_UNEXPECTED_NODE, SCHED_E_NAMESPACE, SCHED_E_INVALIDVALUE,
+   *                            SCHED_E_MISSINGNODE, SCHED_E_MALFORMEDXML, but there may be others.
+   */
+  long validateTaskDefinition(in wstring aDefinitionXML);
+
+  /**
+   * Get the registration information for a task.
+   *
+   * @throws NS_ERROR_FILE_NOT_FOUND if the folder or task do not exist.
+   *
+   * @param aFolderName     Full name of the folder containing the task, starting with "\".
+   * @param aTaskName       Name of the task to read.
+   * @return                Registration information for the task, as XML text.
+   */
+  AString getTaskXML(in wstring aFolderName, in wstring aTaskName);
+
+  /**
+   * Delete a task.
+   *
+   * @throws NS_ERROR_FILE_NOT_FOUND if the folder or task do not exist.
+   *
+   * @param aFolderName     Full name of the folder containing the task, starting with "\".
+   * @param aTaskName       Name of the task to delete.
+   */
+  void deleteTask(in wstring aFolderName, in wstring aTaskName);
+
+  /**
+   * List the names of all tasks in a task folder.
+   *
+   * @throws NS_ERROR_FILE_NOT_FOUND if the folder doesn't exist.
+   *
+   * @param aFolderName     The full name of the task folder to enumerate, starting with "\".
+   *
+   * @return                An array with the names of the tasks found.
+   */
+  Array<AString> getFolderTasks(in wstring aFolderName);
+
+  /**
+   * Create a new task subfolder under a given parent folder.
+   *
+   * @throws NS_ERROR_FILE_NOT_FOUND if the parent folder does not exist.
+   * @throws NS_ERROR_FILE_ALREADY_EXISTS if the subfolder already exists.
+   *
+   * @param aParentFolderName       Immediate parent for the new folder, starting with "\".
+   * @param aSubFolderName          Name of the new folder to create.
+   */
+  void createFolder(in wstring aParentFolderName, in wstring aSubFolderName);
+
+  /**
+   * Delete a folder.
+   *
+   * @throws NS_ERROR_FILE_NOT_FOUND if the parent folder does not exist.
+   * @throws NS_ERROR_FILE_DIR_NOT_EMPTY if the folder was not empty.
+   *
+   * @param aParentFolderName       Immediate parent of the folder to delete, starting with "\".
+   * @param aSubFolderName          Name of the folder to delete.
+   */
+  void deleteFolder(in wstring aParentFolderName, in wstring aSubFolderName);
+};
diff --git a/toolkit/components/taskscheduler/nsWinTaskScheduler.cpp b/toolkit/components/taskscheduler/nsWinTaskScheduler.cpp
new file mode 100644
index 0000000000..21b2909805
--- /dev/null
+++ b/toolkit/components/taskscheduler/nsWinTaskScheduler.cpp
@@ -0,0 +1,308 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode:nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWinTaskScheduler.h"
+
+#include <windows.h>
+#include <comdef.h>
+#include <taskschd.h>
+
+#include "nsString.h"
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/ResultVariant.h"
+
+using namespace mozilla;
+
+struct SysFreeStringDeleter {
+  void operator()(BSTR aPtr) { ::SysFreeString(aPtr); }
+};
+using BStrPtr = mozilla::UniquePtr<OLECHAR, SysFreeStringDeleter>;
+
+static nsresult ToNotFoundOrFailure(HRESULT hr) {
+  if (hr == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND)) {
+    return NS_ERROR_FILE_NOT_FOUND;
+  } else {
+    return NS_ERROR_FAILURE;
+  }
+}
+
+static nsresult ToAlreadyExistsOrFailure(HRESULT hr) {
+  if (hr == HRESULT_FROM_WIN32(ERROR_ALREADY_EXISTS)) {
+    return NS_ERROR_FILE_ALREADY_EXISTS;
+  } else {
+    return NS_ERROR_FAILURE;
+  }
+}
+
+[[nodiscard]] static Result<RefPtr<ITaskFolder>, HRESULT> GetTaskFolder(
+    const char16_t* aFolderName) {
+  HRESULT hr;
+  RefPtr<ITaskService> scheduler = nullptr;
+
+  hr = CoCreateInstance(CLSID_TaskScheduler, nullptr, CLSCTX_INPROC_SERVER,
+                        IID_ITaskService, getter_AddRefs(scheduler));
+  if (FAILED(hr)) {
+    return Err(hr);
+  }
+
+  // Connect to the local Task Scheduler.
+  hr = scheduler->Connect(VARIANT{}, VARIANT{}, VARIANT{}, VARIANT{});
+  if (FAILED(hr)) {
+    return Err(hr);
+  }
+
+  BStrPtr bstrFolderName =
+      BStrPtr(::SysAllocString(reinterpret_cast<const OLECHAR*>(aFolderName)));
+
+  RefPtr<ITaskFolder> folder = nullptr;
+  hr = scheduler->GetFolder(bstrFolderName.get(), getter_AddRefs(folder));
+  if (FAILED(hr)) {
+    return Err(hr);
+  }
+
+  return folder;
+}
+
+[[nodiscard]] static Result<RefPtr<IRegisteredTask>, HRESULT> GetRegisteredTask(
+    const char16_t* aFolderName, const char16_t* aTaskName) {
+  auto folder = GetTaskFolder(aFolderName);
+  if (!folder.isOk()) {
+    return Err(folder.unwrapErr());
+  }
+
+  BStrPtr bstrTaskName =
+      BStrPtr(::SysAllocString(reinterpret_cast<const OLECHAR*>(aTaskName)));
+
+  RefPtr<IRegisteredTask> task = nullptr;
+  HRESULT hr =
+      folder.unwrap()->GetTask(bstrTaskName.get(), getter_AddRefs(task));
+  if (FAILED(hr)) {
+    return Err(hr);
+  }
+
+  return task;
+}
+
+NS_IMPL_ISUPPORTS(nsWinTaskSchedulerService, nsIWinTaskSchedulerService)
+
+NS_IMETHODIMP
+nsWinTaskSchedulerService::GetTaskXML(const char16_t* aFolderName,
+                                      const char16_t* aTaskName,
+                                      nsAString& aResult) {
+  if (!aFolderName || !aTaskName) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  auto task = GetRegisteredTask(aFolderName, aTaskName);
+  if (!task.isOk()) {
+    return ToNotFoundOrFailure(task.unwrapErr());
+  }
+
+  {
+    BSTR bstrXml = nullptr;
+    if (FAILED(task.unwrap()->get_Xml(&bstrXml))) {
+      return NS_ERROR_FAILURE;
+    }
+
+    aResult.Assign(bstrXml, ::SysStringLen(bstrXml));
+    ::SysFreeString(bstrXml);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWinTaskSchedulerService::RegisterTask(const char16_t* aFolderName,
+                                        const char16_t* aTaskName,
+                                        const char16_t* aDefinitionXML,
+                                        bool aUpdateExisting) {
+  if (!aFolderName || !aTaskName || !aDefinitionXML) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  auto folder = GetTaskFolder(aFolderName);
+  if (!folder.isOk()) {
+    return ToNotFoundOrFailure(folder.unwrapErr());
+  }
+
+  BStrPtr bstrTaskName =
+      BStrPtr(::SysAllocString(reinterpret_cast<const OLECHAR*>(aTaskName)));
+  BStrPtr bstrXml = BStrPtr(
+      ::SysAllocString(reinterpret_cast<const OLECHAR*>(aDefinitionXML)));
+  LONG flags = aUpdateExisting ? TASK_CREATE_OR_UPDATE : TASK_CREATE;
+  TASK_LOGON_TYPE logonType = TASK_LOGON_INTERACTIVE_TOKEN;
+
+  // The outparam is not needed, but not documented as optional.
+  RefPtr<IRegisteredTask> unusedTaskOutput = nullptr;
+  HRESULT hr = folder.unwrap()->RegisterTask(
+      bstrTaskName.get(), bstrXml.get(), flags, VARIANT{} /* userId */,
+      VARIANT{} /* password */, logonType, VARIANT{} /* sddl */,
+      getter_AddRefs(unusedTaskOutput));
+
+  if (FAILED(hr)) {
+    return ToAlreadyExistsOrFailure(hr);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWinTaskSchedulerService::ValidateTaskDefinition(
+    const char16_t* aDefinitionXML, int32_t* aResult) {
+  if (!aDefinitionXML) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  auto folder = GetTaskFolder(reinterpret_cast<const char16_t*>(L"\\"));
+  if (!folder.isOk()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  BStrPtr bstrXml = BStrPtr(
+      ::SysAllocString(reinterpret_cast<const OLECHAR*>(aDefinitionXML)));
+  LONG flags = TASK_VALIDATE_ONLY;
+  TASK_LOGON_TYPE logonType = TASK_LOGON_INTERACTIVE_TOKEN;
+
+  // The outparam is not needed, but not documented as optional.
+  RefPtr<IRegisteredTask> unusedTaskOutput = nullptr;
+  HRESULT hr = folder.unwrap()->RegisterTask(
+      nullptr /* path */, bstrXml.get(), flags, VARIANT{} /* userId */,
+      VARIANT{} /* password */, logonType, VARIANT{} /* sddl */,
+      getter_AddRefs(unusedTaskOutput));
+
+  if (aResult) {
+    *aResult = hr;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWinTaskSchedulerService::DeleteTask(const char16_t* aFolderName,
+                                      const char16_t* aTaskName) {
+  if (!aFolderName || !aTaskName) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  auto folder = GetTaskFolder(aFolderName);
+  if (!folder.isOk()) {
+    return ToNotFoundOrFailure(folder.unwrapErr());
+  }
+
+  BStrPtr bstrTaskName =
+      BStrPtr(::SysAllocString(reinterpret_cast<const OLECHAR*>(aTaskName)));
+
+  HRESULT hr = folder.unwrap()->DeleteTask(bstrTaskName.get(), 0 /* flags */);
+  if (FAILED(hr)) {
+    return ToNotFoundOrFailure(hr);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWinTaskSchedulerService::GetFolderTasks(const char16_t* aFolderName,
+                                          nsTArray<nsString>& aResult) {
+  if (!aFolderName) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  auto folder = GetTaskFolder(aFolderName);
+  if (!folder.isOk()) {
+    return ToNotFoundOrFailure(folder.unwrapErr());
+  }
+
+  RefPtr<IRegisteredTaskCollection> taskCollection = nullptr;
+  if (FAILED(folder.unwrap()->GetTasks(TASK_ENUM_HIDDEN,
+                                       getter_AddRefs(taskCollection)))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  LONG taskCount = 0;
+  if (FAILED(taskCollection->get_Count(&taskCount))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  aResult.Clear();
+
+  for (LONG i = 0; i < taskCount; ++i) {
+    RefPtr<IRegisteredTask> task = nullptr;
+
+    // nb: Collections are indexed from 1.
+    if (FAILED(taskCollection->get_Item(_variant_t(i + 1),
+                                        getter_AddRefs(task)))) {
+      return NS_ERROR_FAILURE;
+    }
+
+    BStrPtr bstrTaskName;
+    {
+      BSTR tempTaskName = nullptr;
+      if (FAILED(task->get_Name(&tempTaskName))) {
+        return NS_ERROR_FAILURE;
+      }
+      bstrTaskName = BStrPtr(tempTaskName);
+    }
+
+    aResult.AppendElement(nsString(bstrTaskName.get()));
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWinTaskSchedulerService::CreateFolder(const char16_t* aParentFolderName,
+                                        const char16_t* aSubFolderName) {
+  if (!aParentFolderName || !aSubFolderName) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  auto parentFolder = GetTaskFolder(aParentFolderName);
+  if (!parentFolder.isOk()) {
+    return ToNotFoundOrFailure(parentFolder.unwrapErr());
+  }
+
+  BStrPtr bstrSubFolderName = BStrPtr(
+      ::SysAllocString(reinterpret_cast<const OLECHAR*>(aSubFolderName)));
+
+  HRESULT hr = parentFolder.unwrap()->CreateFolder(bstrSubFolderName.get(),
+                                                   VARIANT{},  // sddl
+                                                   nullptr);   // ppFolder
+
+  if (FAILED(hr)) {
+    return ToAlreadyExistsOrFailure(hr);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWinTaskSchedulerService::DeleteFolder(const char16_t* aParentFolderName,
+                                        const char16_t* aSubFolderName) {
+  if (!aParentFolderName || !aSubFolderName) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  auto parentFolder = GetTaskFolder(aParentFolderName);
+  if (!parentFolder.isOk()) {
+    return ToNotFoundOrFailure(parentFolder.unwrapErr());
+  }
+
+  BStrPtr bstrSubFolderName = BStrPtr(
+      ::SysAllocString(reinterpret_cast<const OLECHAR*>(aSubFolderName)));
+
+  HRESULT hr = parentFolder.unwrap()->DeleteFolder(bstrSubFolderName.get(),
+                                                   0 /* flags */);
+
+  if (FAILED(hr)) {
+    if (hr == HRESULT_FROM_WIN32(ERROR_DIR_NOT_EMPTY)) {
+      return NS_ERROR_FILE_DIR_NOT_EMPTY;
+    } else {
+      return ToNotFoundOrFailure(hr);
+    }
+  }
+
+  return NS_OK;
+}
diff --git a/toolkit/components/taskscheduler/nsWinTaskScheduler.h b/toolkit/components/taskscheduler/nsWinTaskScheduler.h
new file mode 100644
index 0000000000..e89c1b9b05
--- /dev/null
+++ b/toolkit/components/taskscheduler/nsWinTaskScheduler.h
@@ -0,0 +1,22 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WINTASKSCHEDULER_H_
+#define WINTASKSCHEDULER_H_
+
+#include "nsIWinTaskSchedulerService.h"
+
+class nsWinTaskSchedulerService : public nsIWinTaskSchedulerService {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIWINTASKSCHEDULERSERVICE
+
+  nsWinTaskSchedulerService() = default;
+
+ protected:
+  virtual ~nsWinTaskSchedulerService() = default;
+};
+
+#endif /* WINTASKSCHEDULER_H_ */
diff --git a/toolkit/components/taskscheduler/tests/xpcshell/test_TaskScheduler.js b/toolkit/components/taskscheduler/tests/xpcshell/test_TaskScheduler.js
new file mode 100644
index 0000000000..74ad1bf197
--- /dev/null
+++ b/toolkit/components/taskscheduler/tests/xpcshell/test_TaskScheduler.js
@@ -0,0 +1,55 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+// Cross-platform task scheduler tests.
+//
+// There's not much that can be done here without allowing the task to run, so this
+// only touches on the basics of argument checking. On platforms without a task
+// scheduler implementation, these interfaces currently do nothing else.
+
+const { updateAppInfo } = ChromeUtils.importESModule(
+  "resource://testing-common/AppInfo.sys.mjs"
+);
+updateAppInfo();
+
+const { TaskScheduler } = ChromeUtils.import(
+  "resource://gre/modules/TaskScheduler.jsm"
+);
+
+registerCleanupFunction(async () => {
+  await TaskScheduler.deleteAllTasks();
+});
+
+add_task(async function test_gen() {
+  await TaskScheduler.registerTask(
+    "FOO",
+    "xyz",
+    TaskScheduler.MIN_INTERVAL_SECONDS,
+    {
+      disabled: true,
+    }
+  );
+
+  Assert.equal(
+    await TaskScheduler.taskExists("FOO"),
+    true,
+    "Task should exist after we created it."
+  );
+
+  await TaskScheduler.deleteTask("FOO");
+
+  Assert.equal(
+    await TaskScheduler.taskExists("FOO"),
+    false,
+    "Task should not exist after we deleted it."
+  );
+
+  await Assert.rejects(
+    TaskScheduler.registerTask("BAR", "123", 1, {
+      disabled: true,
+    }),
+    /Interval is too short/
+  );
+});
diff --git a/toolkit/components/taskscheduler/tests/xpcshell/test_TaskSchedulerMacOSImpl.js b/toolkit/components/taskscheduler/tests/xpcshell/test_TaskSchedulerMacOSImpl.js
new file mode 100644
index 0000000000..921f91207e
--- /dev/null
+++ b/toolkit/components/taskscheduler/tests/xpcshell/test_TaskSchedulerMacOSImpl.js
@@ -0,0 +1,112 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+// Unit tests for macOS scheduled task generation.
+
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+const { updateAppInfo } = ChromeUtils.importESModule(
+  "resource://testing-common/AppInfo.sys.mjs"
+);
+updateAppInfo();
+
+const { TaskScheduler } = ChromeUtils.import(
+  "resource://gre/modules/TaskScheduler.jsm"
+);
+const { MacOSImpl } = ChromeUtils.import(
+  "resource://gre/modules/TaskSchedulerMacOSImpl.jsm"
+);
+
+function getFirefoxExecutableFilename() {
+  if (AppConstants.platform === "win") {
+    return AppConstants.MOZ_APP_NAME + ".exe";
+  }
+  return AppConstants.MOZ_APP_NAME;
+}
+
+// Returns a nsIFile to the firefox.exe (really, application) executable file.
+function getFirefoxExecutableFile() {
+  let file = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
+  file = Services.dirsvc.get("GreBinD", Ci.nsIFile);
+
+  file.append(getFirefoxExecutableFilename());
+  return file;
+}
+
+const uuidGenerator = Services.uuid;
+
+function randomName() {
+  return (
+    "moz-taskschd-test-" +
+    uuidGenerator
+      .generateUUID()
+      .toString()
+      .slice(1, -1)
+  );
+}
+
+add_task(async function test_all() {
+  let labels;
+  Assert.notEqual(await MacOSImpl._uid(), 0, "Should not be running as root");
+
+  let id1 = randomName();
+  let id2 = randomName();
+  Assert.notEqual(id1, id2, "Random labels should not collide");
+
+  await MacOSImpl.registerTask(
+    id1,
+    getFirefoxExecutableFile().path,
+    TaskScheduler.MIN_INTERVAL_SECONDS,
+    { disabled: true }
+  );
+
+  await MacOSImpl.registerTask(
+    id2,
+    getFirefoxExecutableFile().path,
+    TaskScheduler.MIN_INTERVAL_SECONDS,
+    { disabled: true }
+  );
+
+  let label1 = MacOSImpl._formatLabelForThisApp(id1);
+  let label2 = MacOSImpl._formatLabelForThisApp(id2);
+
+  // We don't assert equality because there may be existing tasks, concurrent
+  // tests, etc.  This also means we can't reasonably tests `deleteAllTasks()`.
+  labels = await MacOSImpl._listAllLabelsForThisApp();
+  Assert.ok(
+    labels.includes(label1),
+    `Task ${label1} should have been registered in ${JSON.stringify(labels)}`
+  );
+  Assert.ok(
+    labels.includes(label2),
+    `Task ${label2} should have been registered in ${JSON.stringify(labels)}`
+  );
+
+  Assert.ok(await MacOSImpl.deleteTask(id1));
+
+  labels = await MacOSImpl._listAllLabelsForThisApp();
+  Assert.ok(
+    !labels.includes(label1),
+    `Task ${label1} should no longer be registered in ${JSON.stringify(labels)}`
+  );
+  Assert.ok(
+    labels.includes(label2),
+    `Task ${label2} should still be registered in ${JSON.stringify(labels)}`
+  );
+
+  Assert.ok(await MacOSImpl.deleteTask(id2));
+
+  labels = await MacOSImpl._listAllLabelsForThisApp();
+  Assert.ok(
+    !labels.includes(label1),
+    `Task ${label1} should no longer be registered in ${JSON.stringify(labels)}`
+  );
+  Assert.ok(
+    !labels.includes(label2),
+    `Task ${label2} should no longer be registered in ${JSON.stringify(labels)}`
+  );
+});
diff --git a/toolkit/components/taskscheduler/tests/xpcshell/test_TaskSchedulerWinImpl.js b/toolkit/components/taskscheduler/tests/xpcshell/test_TaskSchedulerWinImpl.js
new file mode 100644
index 0000000000..438c5d397f
--- /dev/null
+++ b/toolkit/components/taskscheduler/tests/xpcshell/test_TaskSchedulerWinImpl.js
@@ -0,0 +1,206 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+// Unit tests for Windows scheduled task generation.
+
+const { updateAppInfo } = ChromeUtils.importESModule(
+  "resource://testing-common/AppInfo.sys.mjs"
+);
+updateAppInfo();
+
+const { TaskScheduler } = ChromeUtils.import(
+  "resource://gre/modules/TaskScheduler.jsm"
+);
+
+const { WinImpl } = ChromeUtils.import(
+  "resource://gre/modules/TaskSchedulerWinImpl.jsm"
+);
+
+const WinSvc = Cc["@mozilla.org/win-task-scheduler-service;1"].getService(
+  Ci.nsIWinTaskSchedulerService
+);
+
+const uuidGenerator = Services.uuid;
+
+function randomName() {
+  return (
+    "moz-taskschd-test-" +
+    uuidGenerator
+      .generateUUID()
+      .toString()
+      .slice(1, -1)
+  );
+}
+
+const gFolderName = randomName();
+
+// Override task folder name, to prevent colliding with other tests.
+WinImpl._taskFolderName = function() {
+  return gFolderName;
+};
+WinImpl._taskFolderNameParts = function() {
+  return {
+    parentName: "\\",
+    subName: gFolderName,
+  };
+};
+
+registerCleanupFunction(async () => {
+  await TaskScheduler.deleteAllTasks();
+});
+
+add_task(async function test_create() {
+  const taskName = "test-task-1";
+  const rawTaskName = WinImpl._formatTaskName(taskName);
+  const folderName = WinImpl._taskFolderName();
+  const exePath = "C:\\Program Files\\XYZ\\123.exe";
+  const workingDir = "C:\\Program Files\\XYZ";
+  const argsIn = [
+    "x.txt",
+    "c:\\x.txt",
+    'C:\\"HELLO WORLD".txt',
+    "only space.txt",
+  ];
+  const expectedArgsOutStr = [
+    "x.txt",
+    "c:\\x.txt",
+    '"C:\\\\\\"HELLO WORLD\\".txt"',
+    '"only space.txt"',
+  ].join(" ");
+  const description = "Entities: < &. Non-ASCII: abc😀def.";
+  const intervalSecsIn = 2 * 60 * 60; // 2 hours
+  const expectedIntervalOutWin10 = "PT2H"; // Windows 10 regroups by hours and minutes
+  const expectedIntervalOutWin7 = `PT${intervalSecsIn}S`; // Windows 7 doesn't regroup
+
+  await TaskScheduler.registerTask(taskName, exePath, intervalSecsIn, {
+    disabled: true,
+    args: argsIn,
+    description,
+    workingDirectory: workingDir,
+  });
+
+  // Read back the task
+  const readBackXML = WinSvc.getTaskXML(folderName, rawTaskName);
+  const parser = new DOMParser();
+  const doc = parser.parseFromString(readBackXML, "text/xml");
+  Assert.equal(doc.documentElement.tagName, "Task");
+
+  // Check for the values set above
+  Assert.equal(doc.querySelector("Actions Exec Command").textContent, exePath);
+  Assert.equal(
+    doc.querySelector("Actions Exec WorkingDirectory").textContent,
+    workingDir
+  );
+  Assert.equal(
+    doc.querySelector("Actions Exec Arguments").textContent,
+    expectedArgsOutStr
+  );
+  Assert.equal(
+    doc.querySelector("RegistrationInfo Description").textContent,
+    description
+  );
+  Assert.equal(
+    doc.querySelector("RegistrationInfo Author").textContent,
+    Services.appinfo.vendor
+  );
+
+  Assert.equal(doc.querySelector("Settings Enabled").textContent, "false");
+
+  // Note: It's a little too tricky to check for a specific StartBoundary value reliably here, given
+  // that it gets set relative to Date.now(), so I'm skipping that.
+  const intervalOut = doc.querySelector(
+    "Triggers TimeTrigger Repetition Interval"
+  ).textContent;
+  Assert.ok(
+    intervalOut == expectedIntervalOutWin7 ||
+      intervalOut == expectedIntervalOutWin10
+  );
+
+  // Validate the XML
+  WinSvc.validateTaskDefinition(readBackXML);
+
+  // Update
+  const updatedExePath = "C:\\Program Files (x86)\\ABC\\foo.exe";
+  const updatedIntervalSecsIn = 3 * 60 * 60; // 3 hours
+  const expectedUpdatedIntervalOutWin10 = "PT3H";
+  const expectedUpdatedIntervalOutWin7 = `PT${updatedIntervalSecsIn}S`;
+
+  await TaskScheduler.registerTask(
+    taskName,
+    updatedExePath,
+    updatedIntervalSecsIn,
+    {
+      disabled: true,
+      args: argsIn,
+      description,
+      workingDirectory: workingDir,
+    }
+  );
+
+  // Read back the updated task
+  const readBackUpdatedXML = WinSvc.getTaskXML(folderName, rawTaskName);
+  const updatedDoc = parser.parseFromString(readBackUpdatedXML, "text/xml");
+  Assert.equal(updatedDoc.documentElement.tagName, "Task");
+
+  // Check for updated values
+  Assert.equal(
+    updatedDoc.querySelector("Actions Exec Command").textContent,
+    updatedExePath
+  );
+
+  Assert.notEqual(
+    doc.querySelector("Triggers TimeTrigger StartBoundary").textContent,
+    updatedDoc.querySelector("Triggers TimeTrigger StartBoundary").textContent
+  );
+  const updatedIntervalOut = updatedDoc.querySelector(
+    "Triggers TimeTrigger Repetition Interval"
+  ).textContent;
+  Assert.ok(
+    updatedIntervalOut == expectedUpdatedIntervalOutWin7 ||
+      updatedIntervalOut == expectedUpdatedIntervalOutWin10
+  );
+
+  // Check that the folder really was there
+  {
+    const { parentName, subName } = WinImpl._taskFolderNameParts();
+    let threw;
+    try {
+      WinSvc.deleteFolder(parentName, subName);
+    } catch (ex) {
+      threw = ex;
+    }
+    Assert.equal(threw.result, Cr.NS_ERROR_FILE_DIR_NOT_EMPTY);
+  }
+
+  // Delete
+  await TaskScheduler.deleteAllTasks();
+
+  // Check that the folder is gone
+  {
+    const { parentName, subName } = WinImpl._taskFolderNameParts();
+    let threw;
+    try {
+      WinSvc.deleteFolder(parentName, subName);
+    } catch (ex) {
+      threw = ex;
+    }
+    Assert.equal(threw.result, Cr.NS_ERROR_FILE_NOT_FOUND);
+  }
+
+  // Format and validate the XML with the task not disabled
+  const enabledXML = WinImpl._formatTaskDefinitionXML(exePath, intervalSecsIn, {
+    args: argsIn,
+    description,
+    workingDirectory: workingDir,
+  });
+  Assert.equal(WinSvc.validateTaskDefinition(enabledXML), 0 /* S_OK */);
+
+  // Format and validate with no options
+  const basicXML = WinImpl._formatTaskDefinitionXML(
+    "foo",
+    TaskScheduler.MIN_INTERVAL_SECONDS
+  );
+  Assert.equal(WinSvc.validateTaskDefinition(basicXML), 0 /* S_OK */);
+});
diff --git a/toolkit/components/taskscheduler/tests/xpcshell/test_WinTaskSchedulerService.js b/toolkit/components/taskscheduler/tests/xpcshell/test_WinTaskSchedulerService.js
new file mode 100644
index 0000000000..ac0ccad670
--- /dev/null
+++ b/toolkit/components/taskscheduler/tests/xpcshell/test_WinTaskSchedulerService.js
@@ -0,0 +1,187 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+// Unit tests for access to the Windows Task Scheduler via nsIWinTaskSchedulerService.
+
+const svc = Cc["@mozilla.org/win-task-scheduler-service;1"].getService(
+  Ci.nsIWinTaskSchedulerService
+);
+
+function randomName() {
+  return (
+    "moz-taskschd-test-" +
+    Services.uuid
+      .generateUUID()
+      .toString()
+      .slice(1, -1)
+  );
+}
+
+const gParentFolderName = randomName();
+const gParentFolderPath = `\\${gParentFolderName}`;
+const gSubFolderName = randomName();
+const gSubFolderPath = `\\${gParentFolderName}\\${gSubFolderName}`;
+// This folder will not be created
+const gMissingFolderName = randomName();
+const gMissingFolderPath = `\\${gParentFolderName}\\${gMissingFolderName}`;
+
+const gValidTaskXML = `<Task xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
+  <Triggers />
+  <Settings>
+    <Enabled>false</Enabled>
+  </Settings>
+  <Actions>
+    <Exec>
+      <Command>xyz123.exe</Command>
+    </Exec>
+  </Actions>
+</Task>`;
+
+// Missing actions
+const gInvalidTaskXML = `<Task xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
+  <Triggers />
+  <Settings>
+    <Enabled>false</Enabled>
+  </Settings>
+</Task>`;
+
+function cleanup() {
+  let tasksToDelete = svc.getFolderTasks(gSubFolderPath);
+
+  for (const task of tasksToDelete) {
+    svc.deleteTask(gSubFolderPath, task);
+  }
+
+  svc.deleteFolder(gParentFolderPath, gSubFolderName);
+
+  svc.deleteFolder("\\", gParentFolderPath);
+}
+
+registerCleanupFunction(() => {
+  try {
+    cleanup();
+  } catch (_ex) {
+    // Folders may not exist
+  }
+});
+
+add_task(async function test_svc() {
+  /***** FOLDERS *****/
+
+  // Try creating subfolder before parent folder exists
+  Assert.throws(
+    () => svc.createFolder(gParentFolderPath, gSubFolderName),
+    /NS_ERROR_FILE_NOT_FOUND/
+  );
+
+  // Create parent folder
+  svc.createFolder("\\", gParentFolderName);
+
+  // Create subfolder
+  svc.createFolder(gParentFolderPath, gSubFolderName);
+
+  // Try creating existing folder
+  Assert.throws(
+    () => svc.createFolder(gParentFolderPath, gSubFolderName),
+    /NS_ERROR_FILE_ALREADY_EXISTS/
+  );
+
+  // Try deleting nonexistent subfolder
+  Assert.throws(
+    () => svc.deleteFolder(gParentFolderPath, gMissingFolderName),
+    /NS_ERROR_FILE_NOT_FOUND/
+  );
+
+  /***** TASKS *****/
+  const taskNames = [randomName(), randomName(), randomName()];
+
+  // Try enumerating nonexistent subfolder
+  Assert.throws(
+    () => svc.getFolderTasks(gMissingFolderPath),
+    /NS_ERROR_FILE_NOT_FOUND/
+  );
+
+  // List empty subfolder
+  Assert.deepEqual(svc.getFolderTasks(gSubFolderPath), []);
+
+  // Try to create task in nonexistent subfolder
+  Assert.throws(
+    () => svc.registerTask(gMissingFolderPath, taskNames[0], gValidTaskXML),
+    /NS_ERROR_FILE_NOT_FOUND/
+  );
+
+  // Create task 0
+
+  svc.registerTask(gSubFolderPath, taskNames[0], gValidTaskXML);
+
+  // Try to recreate task 0
+  Assert.throws(
+    () => svc.registerTask(gSubFolderPath, taskNames[0], gValidTaskXML),
+    /NS_ERROR_FILE_ALREADY_EXISTS/
+  );
+
+  // Update task 0
+  svc.registerTask(
+    gSubFolderPath,
+    taskNames[0],
+    gValidTaskXML,
+    true /* aUpdateExisting */
+  );
+
+  // Read back XML
+  Assert.ok(svc.getTaskXML(gSubFolderPath, taskNames[0]));
+
+  // Create remaining tasks
+  for (const task of taskNames.slice(1)) {
+    svc.registerTask(gSubFolderPath, task, gValidTaskXML);
+  }
+
+  // Try to create with invalid XML
+  Assert.throws(
+    () => svc.registerTask(gSubFolderPath, randomName(), gInvalidTaskXML),
+    /NS_ERROR_FAILURE/
+  );
+
+  // Validate XML
+  Assert.equal(svc.validateTaskDefinition(gValidTaskXML), 0 /* S_OK */);
+
+  // Try to validate invalid XML
+  Assert.notEqual(svc.validateTaskDefinition(gInvalidTaskXML), 0 /* S_OK */);
+
+  // Test enumeration
+  {
+    let foundTasks = svc.getFolderTasks(gSubFolderPath);
+    foundTasks.sort();
+
+    let allTasks = taskNames.slice();
+    allTasks.sort();
+
+    Assert.deepEqual(foundTasks, allTasks);
+  }
+
+  // Try deleting non-empty folder
+  Assert.throws(
+    () => svc.deleteFolder(gParentFolderPath, gSubFolderName),
+    /NS_ERROR_FILE_DIR_NOT_EMPTY/
+  );
+
+  const missingTaskName = randomName();
+
+  // Try deleting non-existent task
+  Assert.throws(
+    () => svc.deleteTask(gSubFolderName, missingTaskName),
+    /NS_ERROR_FILE_NOT_FOUND/
+  );
+
+  // Try reading non-existent task
+  Assert.throws(
+    () => svc.getTaskXML(gSubFolderPath, missingTaskName),
+    /NS_ERROR_FILE_NOT_FOUND/
+  );
+
+  /***** Cleanup *****/
+  // Explicitly call cleanup() to test that it removes the folder without error.
+  cleanup();
+});
diff --git a/toolkit/components/taskscheduler/tests/xpcshell/xpcshell.ini b/toolkit/components/taskscheduler/tests/xpcshell/xpcshell.ini
new file mode 100644
index 0000000000..ede5742015
--- /dev/null
+++ b/toolkit/components/taskscheduler/tests/xpcshell/xpcshell.ini
@@ -0,0 +1,13 @@
+[test_TaskSchedulerMacOSImpl.js]
+run-if = os == "mac" # Test of macOS backend
+skip-if =
+  apple_silicon  # bug 1707753
+  apple_catalina # Bug 1713329
+[test_WinTaskSchedulerService.js]
+run-if = os == "win" # Test of Windows only service
+[test_TaskSchedulerWinImpl.js]
+run-if = os == "win" # Test of Windows backend
+[test_TaskScheduler.js]
+skip-if =
+  apple_silicon  # bug 1707753
+  apple_catalina # Bug 1713329