1 files changed, 264 insertions, 0 deletions
diff --git a/xpcom/io/nsAnonymousTemporaryFile.cpp b/xpcom/io/nsAnonymousTemporaryFile.cpp
new file mode 100644
index 0000000000..1c9dce57d5
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+++ b/xpcom/io/nsAnonymousTemporaryFile.cpp
@@ -0,0 +1,264 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "nsAnonymousTemporaryFile.h"
+#include "nsXULAppAPI.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "prio.h"
+#include "SpecialSystemDirectory.h"
+
+#ifdef XP_WIN
+#  include "nsIObserver.h"
+#  include "nsIObserverService.h"
+#  include "mozilla/ResultExtensions.h"
+#  include "mozilla/Services.h"
+#  include "nsIUserIdleService.h"
+#  include "nsISimpleEnumerator.h"
+#  include "nsIFile.h"
+#  include "nsITimer.h"
+#  include "nsCRT.h"
+
+#endif
+
+using namespace mozilla;
+
+// We store the temp files in the system temp dir.
+//
+// On Windows systems in particular we use a sub-directory of the temp
+// directory, because:
+//   1. DELETE_ON_CLOSE is unreliable on Windows, in particular if we power
+//      cycle (and perhaps if we crash) the files are not deleted. We store
+//      the temporary files in a known sub-dir so that we can find and delete
+//      them easily and quickly.
+//   2. On Windows NT the system temp dir is in the user's $HomeDir/AppData,
+//      so we can be sure the user always has write privileges to that
+//      directory; if the sub-dir for our temp files was in some shared location
+//      and was created by a privileged user, it's possible that other users
+//      wouldn't have write access to that sub-dir. (Non-Windows systems
+//      don't store their temp files in a sub-dir, so this isn't an issue on
+//      those platforms).
+//   3. Content processes can access the system temp dir
+//      (NS_GetSpecialDirectory fails on NS_APP_USER_PROFILE_LOCAL_50_DIR
+//      for content process for example, which is where we previously stored
+//      temp files on Windows). This argument applies to all platforms, not
+//      just Windows.
+static nsresult GetTempDir(nsIFile** aTempDir) {
+  if (NS_WARN_IF(!aTempDir)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  nsCOMPtr<nsIFile> tmpFile;
+  nsresult rv =
+      GetSpecialSystemDirectory(OS_TemporaryDirectory, getter_AddRefs(tmpFile));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+#ifdef XP_WIN
+  // On windows DELETE_ON_CLOSE is unreliable, so we store temporary files
+  // in a subdir of the temp dir and delete that in an idle service observer
+  // to ensure it's been cleared.
+  rv = tmpFile->AppendNative(nsDependentCString("mozilla-temp-files"));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  rv = tmpFile->Create(nsIFile::DIRECTORY_TYPE, 0700);
+  if (rv != NS_ERROR_FILE_ALREADY_EXISTS && NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+#endif
+
+  tmpFile.forget(aTempDir);
+
+  return NS_OK;
+}
+
+nsresult NS_OpenAnonymousTemporaryNsIFile(nsIFile** aFile) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  if (NS_WARN_IF(!aFile)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsresult rv;
+  nsCOMPtr<nsIFile> tmpFile;
+  rv = GetTempDir(getter_AddRefs(tmpFile));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // Give the temp file a name with a random element. CreateUnique will also
+  // append a counter to the name if it encounters a name collision. Adding
+  // a random element to the name reduces the likelihood of a name collision,
+  // so that CreateUnique() doesn't end up trying a lot of name variants in
+  // its "try appending an incrementing counter" loop, as file IO can be
+  // expensive on some mobile flash drives.
+  nsAutoCString name("mozilla-temp-");
+  name.AppendInt(rand());
+
+  rv = tmpFile->AppendNative(name);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = tmpFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  tmpFile.forget(aFile);
+  return NS_OK;
+}
+
+nsresult NS_OpenAnonymousTemporaryFile(PRFileDesc** aOutFileDesc) {
+  nsCOMPtr<nsIFile> tmpFile;
+  nsresult rv = NS_OpenAnonymousTemporaryNsIFile(getter_AddRefs(tmpFile));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  rv = tmpFile->OpenNSPRFileDesc(PR_RDWR | nsIFile::DELETE_ON_CLOSE, PR_IRWXU,
+                                 aOutFileDesc);
+
+  return rv;
+}
+
+#ifdef XP_WIN
+
+// On Windows we have an idle service observer that runs some time after
+// startup and deletes any stray anonymous temporary files...
+
+// Duration of idle time before we'll get a callback whereupon we attempt to
+// remove any stray and unused anonymous temp files.
+#  define TEMP_FILE_IDLE_TIME_S 30
+
+// The nsAnonTempFileRemover is created in a timer, which sets an idle observer.
+// This is expiration time (in ms) which initial timer is set for (3 minutes).
+#  define SCHEDULE_TIMEOUT_MS 3 * 60 * 1000
+
+#  define XPCOM_SHUTDOWN_TOPIC "xpcom-shutdown"
+
+// This class adds itself as an idle observer. When the application has
+// been idle for about 30 seconds we'll get a notification, whereupon we'll
+// attempt to delete ${TempDir}/mozilla-temp-files/. This is to ensure all
+// temp files that were supposed to be deleted on application exit were actually
+// deleted, as they may not be if we previously crashed. See bugs 572579 and
+// 785662. This is only needed on some versions of Windows,
+// nsIFile::DELETE_ON_CLOSE works on other platforms.
+// This class adds itself as a shutdown observer so that it can cancel the
+// idle observer and its timer on shutdown. Note: the observer and idle
+// services hold references to instances of this object, and those references
+// are what keep this object alive.
+class nsAnonTempFileRemover final : public nsIObserver, public nsINamed {
+ public:
+  NS_DECL_ISUPPORTS
+
+  nsAnonTempFileRemover() {}
+
+  nsresult Init() {
+    // We add the idle observer in a timer, so that the app has enough
+    // time to start up before we add the idle observer. If we register the
+    // idle observer too early, it will be registered before the fake idle
+    // service is installed when running in xpcshell, and this interferes with
+    // the fake idle service, causing xpcshell-test failures.
+    MOZ_TRY_VAR(mTimer, NS_NewTimerWithObserver(this, SCHEDULE_TIMEOUT_MS,
+                                                nsITimer::TYPE_ONE_SHOT));
+
+    // Register shutdown observer so we can cancel the timer if we shutdown
+    // before the timer runs.
+    nsCOMPtr<nsIObserverService> obsSrv = services::GetObserverService();
+    if (NS_WARN_IF(!obsSrv)) {
+      return NS_ERROR_FAILURE;
+    }
+    return obsSrv->AddObserver(this, XPCOM_SHUTDOWN_TOPIC, false);
+  }
+
+  void Cleanup() {
+    // Cancel timer.
+    if (mTimer) {
+      mTimer->Cancel();
+      mTimer = nullptr;
+    }
+    // Remove idle service observer.
+    nsCOMPtr<nsIUserIdleService> idleSvc =
+        do_GetService("@mozilla.org/widget/useridleservice;1");
+    if (idleSvc) {
+      idleSvc->RemoveIdleObserver(this, TEMP_FILE_IDLE_TIME_S);
+    }
+    // Remove shutdown observer.
+    nsCOMPtr<nsIObserverService> obsSrv = services::GetObserverService();
+    if (obsSrv) {
+      obsSrv->RemoveObserver(this, XPCOM_SHUTDOWN_TOPIC);
+    }
+  }
+
+  NS_IMETHODIMP Observe(nsISupports* aSubject, const char* aTopic,
+                        const char16_t* aData) {
+    if (nsCRT::strcmp(aTopic, NS_TIMER_CALLBACK_TOPIC) == 0 &&
+        NS_FAILED(RegisterIdleObserver())) {
+      Cleanup();
+    } else if (nsCRT::strcmp(aTopic, OBSERVER_TOPIC_IDLE) == 0) {
+      // The user has been idle for a while, clean up the temp files.
+      // The idle service will drop its reference to this object after
+      // we exit, destroying this object.
+      RemoveAnonTempFileFiles();
+      Cleanup();
+    } else if (nsCRT::strcmp(aTopic, XPCOM_SHUTDOWN_TOPIC) == 0) {
+      Cleanup();
+    }
+    return NS_OK;
+  }
+
+  NS_IMETHODIMP GetName(nsACString& aName) {
+    aName.AssignLiteral("nsAnonTempFileRemover");
+    return NS_OK;
+  }
+
+  nsresult RegisterIdleObserver() {
+    // Add this as an idle observer. When we've been idle for
+    // TEMP_FILE_IDLE_TIME_S seconds, we'll get a notification, and we'll then
+    // try to delete any stray temp files.
+    nsCOMPtr<nsIUserIdleService> idleSvc =
+        do_GetService("@mozilla.org/widget/useridleservice;1");
+    if (!idleSvc) {
+      return NS_ERROR_FAILURE;
+    }
+    return idleSvc->AddIdleObserver(this, TEMP_FILE_IDLE_TIME_S);
+  }
+
+  void RemoveAnonTempFileFiles() {
+    nsCOMPtr<nsIFile> tmpDir;
+    nsresult rv = GetTempDir(getter_AddRefs(tmpDir));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+
+    // Remove the directory recursively.
+    tmpDir->Remove(true);
+  }
+
+ private:
+  ~nsAnonTempFileRemover() {}
+
+  nsCOMPtr<nsITimer> mTimer;
+};
+
+NS_IMPL_ISUPPORTS(nsAnonTempFileRemover, nsIObserver, nsINamed)
+
+nsresult CreateAnonTempFileRemover() {
+  // Create a temp file remover. If Init() succeeds, the temp file remover is
+  // kept alive by a reference held by the observer service, since the temp file
+  // remover is a shutdown observer. We only create the temp file remover if
+  // we're running in the main process; there's no point in doing the temp file
+  // removal multiple times per startup.
+  if (!XRE_IsParentProcess()) {
+    return NS_OK;
+  }
+  RefPtr<nsAnonTempFileRemover> tempRemover = new nsAnonTempFileRemover();
+  return tempRemover->Init();
+}
+
+#endif