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-rw-r--r--xpcom/io/nsAnonymousTemporaryFile.cpp264
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diff --git a/xpcom/io/nsAnonymousTemporaryFile.cpp b/xpcom/io/nsAnonymousTemporaryFile.cpp
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+/* -*- 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