Add SIGTERM support (#12881)

Author: naftaly

Crashlytics/Crashlytics/Controllers/FIRCLSMetricKitManager.m

@@ -438,6 +438,8 @@ - (NSString *)getSignalName:(NSNumber *)signalCode {
       return @"SIGSYS";
     case SIGTRAP:
       return @"SIGTRAP";
+    case SIGTERM:
+      return @"SIGTERM";
     default:
       return @"UNKNOWN";
   }

Crashlytics/Crashlytics/Handlers/FIRCLSMachException.c

@@ -150,6 +150,8 @@ exception_mask_t FIRCLSMachExceptionMaskForSignal(int signal) {
       return EXC_MASK_CRASH;
     case SIGFPE:
       return EXC_MASK_ARITHMETIC;
+    case SIGTERM:
+      return EXC_MASK_CRASH;
   }
 
   return 0;

Crashlytics/Crashlytics/Handlers/FIRCLSSignal.c

@@ -21,8 +21,17 @@
 #include <stdlib.h>
 
 #if CLS_SIGNAL_SUPPORTED
-static const int FIRCLSFatalSignals[FIRCLSSignalCount] = {SIGABRT, SIGBUS, SIGFPE, SIGILL,
-                                                          SIGSEGV, SIGSYS, SIGTRAP};
+static const int FIRCLSFatalSignals[FIRCLSSignalCount] = {
+    SIGABRT, SIGBUS, SIGFPE, SIGILL,
+    SIGSEGV, SIGSYS, SIGTRAP,
+    // SIGTERM can be caught and is usually sent by iOS and variants
+    // when Apple wants to try and gracefully shutdown the app
+    // before sending a SIGKILL (which can't be caught).
+    // Some areas I've seen this happen are:
+    // - When the OS updates an app.
+    // - In some circumstances for Watchdog Events.
+    // - Resource overuse (CPU, Disk, ...).
+    SIGTERM};
 
 #if CLS_USE_SIGALTSTACK
 static void FIRCLSSignalInstallAltStack(FIRCLSSignalReadContext *roContext);
@@ -237,6 +246,9 @@ void FIRCLSSignalNameLookup(int number, int code, const char **name, const char
     case SIGTRAP:
       *name = "SIGTRAP";
       break;
+    case SIGTERM:
+      *name = "SIGTERM";
+      break;
     default:
       *name = "UNKNOWN";
       break;

Crashlytics/Crashlytics/Handlers/FIRCLSSignal.h

@@ -30,7 +30,8 @@
 #endif
 
 #if CLS_SIGNAL_SUPPORTED
-#define FIRCLSSignalCount (7)
+// keep in sync with the list in _FIRCLSFatalSignals_.
+#define FIRCLSSignalCount (8)
 
 typedef struct {
   const char* path;