Merge pull request #802 from mixpanel/fix-signal-handler

Fix signal handler
mixpanel · Oct 10, 2018 · f9e78d8 · f9e78d8
2 parents 0ca59de + 3c99e92
commit f9e78d8
Showing 1 changed file with 13 additions and 9 deletions.
diff --git a/Mixpanel/MixpanelExceptionHandler.m b/Mixpanel/MixpanelExceptionHandler.m
@@ -11,7 +11,6 @@
 #import "MixpanelPrivate.h"
 #import "MPLogger.h"
 #include <libkern/OSAtomic.h>
-#include <execinfo.h>
 
 static NSString * const UncaughtExceptionHandlerSignalExceptionName = @"UncaughtExceptionHandlerSignalExceptionName";
 static NSString * const UncaughtExceptionHandlerSignalKey = @"UncaughtExceptionHandlerSignalKey";
@@ -43,7 +42,6 @@ - (instancetype)init {
     if (self) {
         // Create a hash table of weak pointers to mixpanel instances
         _mixpanelInstances = [NSHashTable weakObjectsHashTable];
-
         _prev_signal_handlers = calloc(NSIG, sizeof(struct sigaction));
 
         // Install our handler
@@ -64,7 +62,7 @@ - (void)setupHandlers {
     sigemptyset(&action.sa_mask);
     action.sa_flags = SA_SIGINFO;
     action.sa_sigaction = &MPSignalHandler;
-    int signals[] = {SIGABRT, SIGILL, SIGSEGV, SIGFPE, SIGBUS, SIGPIPE};
+    int signals[] = {SIGABRT, SIGILL, SIGSEGV, SIGFPE, SIGBUS};
     for (int i = 0; i < sizeof(signals) / sizeof(int); i++) {
         struct sigaction prev_action;
         int err = sigaction(signals[i], &action, &prev_action);
@@ -82,26 +80,32 @@ - (void)addMixpanelInstance:(Mixpanel *)instance {
     [self.mixpanelInstances addObject:instance];
 }
 
-void MPSignalHandler(int signal, struct __siginfo *info, void *context) {
+void MPSignalHandler(int signalNumber, struct __siginfo *info, void *context) {
     MixpanelExceptionHandler *handler = [MixpanelExceptionHandler sharedHandler];
 
     int32_t exceptionCount = OSAtomicIncrement32(&UncaughtExceptionCount);
     if (exceptionCount <= UncaughtExceptionMaximum) {
-        NSDictionary *userInfo = @{UncaughtExceptionHandlerSignalKey: @(signal)};
+        NSDictionary *userInfo = @{UncaughtExceptionHandlerSignalKey: @(signalNumber)};
         NSException *exception = [NSException exceptionWithName:UncaughtExceptionHandlerSignalExceptionName
-                                                         reason:[NSString stringWithFormat:@"Signal %d was raised.", signal]
+                                                         reason:[NSString stringWithFormat:@"Signal %d was raised.", signalNumber]
                                                        userInfo:userInfo];
 
         [handler mp_handleUncaughtException:exception];
     }
 
-    struct sigaction prev_action = handler.prev_signal_handlers[signal];
+    struct sigaction prev_action = handler.prev_signal_handlers[signalNumber];
+    // Since there is no way to pass through to the default handler, re-raise the signal as our best efforts
+    if (prev_action.sa_handler == SIG_DFL) {
+        signal(signalNumber, SIG_DFL);
+        raise(signalNumber);
+        return;
+    }
     if (prev_action.sa_flags & SA_SIGINFO) {
         if (prev_action.sa_sigaction) {
-            prev_action.sa_sigaction(signal, info, context);
+            prev_action.sa_sigaction(signalNumber, info, context);
         }
     } else if (prev_action.sa_handler) {
-        prev_action.sa_handler(signal);
+        prev_action.sa_handler(signalNumber);
     }
 }