Make sure to suspend the logging on app suspension

Failing to do so might trigger ios/macos killing our app with 0xdeadl0cc because the file logger uses flock to serialize writes. Holding any lockfiles during app suspension is disallowed by ios.
monal-im · Nov 20, 2024 · 5f5ad7e · 5f5ad7e
1 parent 8e23499
commit 5f5ad7e
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Showing 3 changed files with 54 additions and 25 deletions.
diff --git a/Monal/Classes/HelperTools.h b/Monal/Classes/HelperTools.h
@@ -92,6 +92,8 @@ void swizzle(Class c, SEL orig, SEL new);
 +(void) installExceptionHandler;
 +(int) pendingCrashreportCount;
 +(void) flushLogsWithTimeout:(double) timeout;
++(void) signalSuspension;
++(void) signalResumption;
 +(void) __attribute__((noreturn)) MLAssertWithText:(NSString*) text andUserData:(id _Nullable) additionalData andFile:(const char* const) file andLine:(int) line andFunc:(const char* const) func;
 +(void) __attribute__((noreturn)) handleRustPanicWithText:(NSString*) text andBacktrace:(NSString*) backtrace;
 +(void) __attribute__((noreturn)) throwExceptionWithName:(NSString*) name reason:(NSString*) reason userInfo:(NSDictionary* _Nullable) userInfo;

diff --git a/Monal/Classes/HelperTools.m b/Monal/Classes/HelperTools.m
@@ -89,6 +89,8 @@ -(void) swizzled_setObject:(id) value forKey:(NSString*) defaultName;
 static char _origProfilePath[1024] = "";
 static char _profilePath[1024] = "";
 static NSObject* _isAppExtensionLock = nil;
+static NSObject* _suspensionHandlingLock = nil;
+static BOOL _suspensionHandlingIsSuspended = NO;
 static NSMutableDictionary* _versionInfoCache;
 static MLStreamRedirect* _stdoutRedirector = nil;
 static MLStreamRedirect* _stderrRedirector = nil;
@@ -383,6 +385,8 @@ @implementation HelperTools
 
 +(void) initialize
 {
+    _suspensionHandlingLock = [NSObject new];
+    _suspensionHandlingIsSuspended = NO;
     _isAppExtensionLock = [NSObject new];
     _versionInfoCache = [NSMutableDictionary new];
 
@@ -2084,6 +2088,30 @@ +(void) flushLogsWithTimeout:(double) timeout
     [MLUDPLogger flushWithTimeout:timeout];
 }
 
++(void) signalSuspension
+{
+    DDLogVerbose(@"Suspending logger queue...");
+    [HelperTools flushLogsWithTimeout:0.100];
+    @synchronized(_suspensionHandlingLock) {
+        dispatch_suspend([DDLog loggingQueue]);
+        _suspensionHandlingIsSuspended = YES;
+    }
+    DDLogVerbose(@"Posting kMonalIsFreezed notification now...");
+    [[NSNotificationCenter defaultCenter] postNotificationName:kMonalIsFreezed object:nil];
+}
+
++(void) signalResumption
+{
+    @synchronized(_suspensionHandlingLock) {
+        if(_suspensionHandlingIsSuspended)
+        {
+            DDLogVerbose(@"Resuming logger queue...");
+            dispatch_resume([DDLog loggingQueue]);
+            _suspensionHandlingIsSuspended = NO;
+        }
+    }
+}
+
 +(void) configureXcodeLogging
 {
     //only start console logger

diff --git a/Monal/Classes/MonalAppDelegate.m b/Monal/Classes/MonalAppDelegate.m
@@ -368,6 +368,9 @@ -(void) updateUnread
 
 -(BOOL) application:(UIApplication*) application willFinishLaunchingWithOptions:(NSDictionary*) launchOptions
 {
+    //resume logging and other core tasks
+    [HelperTools signalResumption];
+
     DDLogInfo(@"App launching with options: %@", launchOptions);
 
     //init IPC and ProcessLock
@@ -639,6 +642,9 @@ -(void) windowHandling:(NSNotification*) notification
     }
     else if([notification.name isEqualToString:@"NSWindowDidBecomeKeyNotification"])
     {
+        //resume logging and other core tasks
+        [HelperTools signalResumption];
+
         DDLogInfo(@"Window got focus (key window)...");
         [MLProcessLock lock];
         @synchronized(self) {
@@ -1134,6 +1140,9 @@ -(void) prepareForFreeze:(NSNotification*) notification
 
 -(void) applicationWillEnterForeground:(UIApplication*) application
 {
+    //resume logging and other core tasks
+    [HelperTools signalResumption];
+
     DDLogInfo(@"Entering FG");
     [MLProcessLock lock];
 
@@ -1239,6 +1248,7 @@ -(void) applicationWillTerminate:(UIApplication *)application
         [[MLXMPPManager sharedInstance] disconnectAll];
         DDLogInfo(@"|~~| T E R M I N A T E D |~~|");
         [DDLog flushLog];
+        [HelperTools flushLogsWithTimeout:0.025];
     }
 }
 
@@ -1447,11 +1457,7 @@ -(void) checkIfBackgroundTaskIsStillNeeded
                         [DDLog flushLog];
                     }
                     else
-                    {
-                        DDLogVerbose(@"Posting kMonalIsFreezed notification now...");
-                        [[NSNotificationCenter defaultCenter] postNotificationName:kMonalIsFreezed object:nil];
-                        [HelperTools flushLogsWithTimeout:0.100];
-                    }
+                        [HelperTools signalSuspension];
                 }];
             }
         }
@@ -1508,11 +1514,7 @@ -(void) addBackgroundTask
                     [[UIApplication sharedApplication] endBackgroundTask:task];
 
                     if(stopped)
-                    {
-                        DDLogVerbose(@"Posting kMonalIsFreezed notification now...");
-                        [[NSNotificationCenter defaultCenter] postNotificationName:kMonalIsFreezed object:nil];
-                        [HelperTools flushLogsWithTimeout:0.100];
-                    }
+                        [HelperTools signalSuspension];
                 }
             }];
         }
@@ -1571,15 +1573,14 @@ -(void) handleBackgroundProcessingTask:(BGTask*) task
                 [task setTaskCompletedWithSuccess:!background];
 
                 if(stopped)
-                {
-                    DDLogVerbose(@"Posting kMonalIsFreezed notification now...");
-                    [[NSNotificationCenter defaultCenter] postNotificationName:kMonalIsFreezed object:nil];
-                    [HelperTools flushLogsWithTimeout:0.100];
-                }
+                    [HelperTools signalSuspension];
             }
         }];
     };
 
+    //resume logging and other core tasks
+    [HelperTools signalResumption];
+
     //only proceed with our BGTASK if the NotificationServiceExtension is not running
     [MLProcessLock lock];
     [[IPC sharedInstance] sendMessage:@"Monal.disconnectAll" withData:nil to:@"NotificationServiceExtension"];
@@ -1679,15 +1680,14 @@ -(void) handleBackgroundRefreshingTask:(BGTask*) task
                 [task setTaskCompletedWithSuccess:!background];
 
                 if(stopped)
-                {
-                    DDLogVerbose(@"Posting kMonalIsFreezed notification now...");
-                    [[NSNotificationCenter defaultCenter] postNotificationName:kMonalIsFreezed object:nil];
-                    [HelperTools flushLogsWithTimeout:0.100];
-                }
+                    [HelperTools signalSuspension];
             }
         }];
     };
 
+    //resume logging and other core tasks
+    [HelperTools signalResumption];
+
     //only proceed with our BGTASK if the NotificationServiceExtension is not running
     [MLProcessLock lock];
     [[IPC sharedInstance] sendMessage:@"Monal.disconnectAll" withData:nil to:@"NotificationServiceExtension"];
@@ -1828,6 +1828,9 @@ -(void) connectIfNecessaryWithOptions:(NSDictionary*) options
 
 -(void) incomingWakeupWithCompletionHandler:(void (^)(UIBackgroundFetchResult result)) completionHandler
 {
+    //resume logging and other core tasks
+    [HelperTools signalResumption];
+
     if(![HelperTools isInBackground])
     {
         DDLogWarn(@"Ignoring incomingWakeupWithCompletionHandler: because app is in FG!");
@@ -1901,11 +1904,7 @@ -(void) incomingWakeupWithCompletionHandler:(void (^)(UIBackgroundFetchResult re
                         completionHandler(UIBackgroundFetchResultFailed);
 
                         if(stopped)
-                        {
-                            DDLogVerbose(@"Posting kMonalIsFreezed notification now...");
-                            [[NSNotificationCenter defaultCenter] postNotificationName:kMonalIsFreezed object:nil];
-                            [HelperTools flushLogsWithTimeout:0.100];
-                        }
+                            [HelperTools signalSuspension];
 
                         //trigger disconnect if we are idle and no timer is blocking us now
                         if(self->_bgTask != UIBackgroundTaskInvalid || self->_bgProcessing != nil || self->_bgRefreshing != nil)