fix(native): Honor system crash reporter forwarding

CHANGELOG.md

@@ -13,6 +13,7 @@
 - Windows: fix HTTP rate limit response header parsing. ([#1732](https://github.com/getsentry/sentry-native/pull/1732))
 - POSIX: prevent condition-variable timeout overflow from busy-spinning flush and shutdown waits. ([#1731](https://github.com/getsentry/sentry-native/pull/1731))
 - Native/macOS: fix thread stack descriptor. ([#1726](https://github.com/getsentry/sentry-native/pull/1726))
+- Native/macOS: honor the system crash reporter forwarding option. ([#1743](https://github.com/getsentry/sentry-native/pull/1743))
 
 ## 0.14.2
 

include/sentry.h

@@ -1836,10 +1836,10 @@ SENTRY_EXPERIMENTAL_API int sentry_set_thread_stack_guarantee(
 /**
  * Enables forwarding to the system crash reporter. Disabled by default.
  *
- * This setting only has an effect when using Crashpad on macOS. If enabled,
- * Crashpad forwards crashes to the macOS system crash reporter. Depending
- * on the crash, this may impact the crash time. Even if enabled, Crashpad
- * may choose not to forward certain crashes.
+ * This setting only has an effect when using the crashpad or native backend on
+ * macOS. If enabled, the crash handler forwards crashes to the macOS system
+ * crash reporter. Depending on the crash, this may impact the crash time. Even
+ * if enabled, the crash handler may choose not to forward certain crashes.
  */
 SENTRY_API void sentry_options_set_system_crash_reporter_enabled(
     sentry_options_t *opts, int enabled);

src/backends/native/sentry_crash_context.h

@@ -285,6 +285,7 @@ typedef struct {
     bool enable_large_attachments;
     bool http_retry;
     uint64_t shutdown_timeout;
+    bool system_crash_reporter_enabled;
 
     // Atomic user consent (sentry_user_consent_t), updated whenever user
     // consent changes so the daemon can honor it at crash time.

src/backends/native/sentry_crash_handler.c

@@ -100,6 +100,47 @@ static sentry_crash_ipc_t *g_crash_ipc = NULL;
 static struct sigaction g_previous_handlers[16];
 static stack_t g_signal_stack = { 0 };
 
+static void
+reset_signal_handlers(void)
+{
+    for (size_t i = 0; i < g_crash_signal_count; i++) {
+        sigaction(g_crash_signals[i], &g_previous_handlers[i], NULL);
+    }
+}
+
+static void
+reraise_signal(int signum)
+{
+    signal(signum, SIG_DFL);
+    raise(signum);
+}
+
+static void
+invoke_previous_signal_handler(int signum, siginfo_t *info, void *context)
+{
+    // Re-enable previous signal handlers before re-raising to prevent loops
+    reset_signal_handlers();
+
+    for (size_t i = 0; i < g_crash_signal_count; i++) {
+        if (g_crash_signals[i] != signum) {
+            continue;
+        }
+
+        struct sigaction *handler = &g_previous_handlers[i];
+        if (handler->sa_handler == SIG_DFL || handler->sa_handler == SIG_IGN) {
+            return;
+        }
+
+        if (handler->sa_flags & SA_SIGINFO) {
+            handler->sa_sigaction(signum, info, context);
+        } else {
+            handler->sa_handler(signum);
+        }
+
+        return;
+    }
+}
+
 /**
  * Get current thread ID (signal-safe)
  */
@@ -251,23 +292,22 @@ safe_build_stack_path(
 static void
 crash_signal_handler(int signum, siginfo_t *info, void *context)
 {
+    sentry_crash_ipc_t *ipc = g_crash_ipc;
+    if (!ipc || !ipc->shmem) {
+        // No IPC available, forward to the previous handler
+        invoke_previous_signal_handler(signum, info, context);
+        // The previous handler returned, fall back to default termination
+        reraise_signal(signum);
+        return;
+    }
+
     // Only handle crash once - check if already processing
     static volatile long handling_crash = 0;
     if (!sentry__atomic_compare_swap(&handling_crash, 0, 1)) {
         // Already handling a crash, just exit immediately
         _exit(1);
     }
 
-    // Re-enable signal to prevent loops
-    signal(signum, SIG_DFL);
-
-    sentry_crash_ipc_t *ipc = g_crash_ipc;
-    if (!ipc || !ipc->shmem) {
-        // No IPC available, just re-raise
-        raise(signum);
-        return;
-    }
-
     sentry_crash_context_t *ctx = ipc->shmem;
     ucontext_t *uctx = (ucontext_t *)context;
 
@@ -762,7 +802,18 @@ crash_signal_handler(int signum, siginfo_t *info, void *context)
         }
     }
 
-    raise(signum);
+    invoke_previous_signal_handler(signum, info, context);
+
+#    if defined(SENTRY_PLATFORM_MACOS)
+    if (!ctx->system_crash_reporter_enabled) {
+        // By convention, use the 128 + signal exit code without re-raising
+        // and invoking the macOS system crash reporter
+        _exit(128 + signum);
+    }
+#    endif
+
+    // The previous handler returned, fall back to default termination
+    reraise_signal(signum);
 }
 
 int
@@ -855,9 +906,7 @@ void
 sentry__crash_handler_shutdown(void)
 {
     // Restore previous signal handlers
-    for (size_t i = 0; i < g_crash_signal_count; i++) {
-        sigaction(g_crash_signals[i], &g_previous_handlers[i], NULL);
-    }
+    reset_signal_handlers();
 
     // Clean up signal stack
     if (g_signal_stack.ss_sp) {

src/backends/sentry_backend_native.c

@@ -293,6 +293,7 @@ native_backend_startup(
 
     // Set crash reporting mode from options
     ctx->crash_reporting_mode = options->crash_reporting_mode;
+    ctx->system_crash_reporter_enabled = options->system_crash_reporter_enabled;
 
     // Pass debug logging setting to daemon
     ctx->debug_enabled = options->debug;

tests/unit/test_native_backend.c

@@ -390,6 +390,7 @@ SENTRY_TEST(crash_context_options_propagation)
     sentry_options_set_ca_certs(options, "/path/to/ca-bundle.crt");
     sentry_options_set_proxy(options, "http://myproxy:3128");
     sentry_options_set_shutdown_timeout(options, 12345);
+    sentry_options_set_system_crash_reporter_enabled(options, true);
 
     // Verify options were set correctly
     TEST_CHECK_STRING_EQUAL(
@@ -417,13 +418,15 @@ SENTRY_TEST(crash_context_options_propagation)
         ctx->user_agent[sizeof(ctx->user_agent) - 1] = '\0';
     }
     ctx->shutdown_timeout = options->shutdown_timeout;
+    ctx->system_crash_reporter_enabled = options->system_crash_reporter_enabled;
 
     // Verify crash context received the values
     TEST_CHECK_STRING_EQUAL(ctx->ca_certs, "/path/to/ca-bundle.crt");
     TEST_CHECK_STRING_EQUAL(ctx->proxy, "http://myproxy:3128");
     // user_agent should have the default SDK user agent
     TEST_CHECK(ctx->user_agent[0] != '\0');
     TEST_CHECK_UINT64_EQUAL(ctx->shutdown_timeout, 12345);
+    TEST_CHECK(ctx->system_crash_reporter_enabled);
 
     sentry_free(ctx);
     sentry_options_free(options);