feat: external crash reporter (#1303)

Author: jpnurmi

CHANGELOG.md

@@ -5,6 +5,7 @@
 **Features**:
 
 - Add support for outgoing W3C traceparent header propagation with the `propagate_traceparent` option. ([#1394](https://github.com/getsentry/sentry-native/pull/1394))
+- Add `sentry_options_set_external_crash_reporter_path` to allow specifying an external crash reporter. ([#1303](https://github.com/getsentry/sentry-native/pull/1303))
 
 **Fixes**:
 

CMakeLists.txt

@@ -751,6 +751,7 @@ endif()
 
 if(SENTRY_BUILD_TESTS)
 	add_subdirectory(tests/unit)
+	add_subdirectory(tests/fixtures/crash_reporter)
 	add_subdirectory(tests/fixtures/screenshot)
 	if(SENTRY_BUILD_BENCHMARKS)
 		set(BENCHMARK_ENABLE_TESTING OFF)

examples/example.c

@@ -494,6 +494,16 @@ main(int argc, char **argv)
         sentry_options_set_enable_logs(options, true);
     }
 
+    if (has_arg(argc, argv, "crash-reporter")) {
+#ifdef SENTRY_PLATFORM_WINDOWS
+        sentry_options_set_external_crash_reporter_pathw(
+            options, L"sentry_crash_reporter.exe");
+#else
+        sentry_options_set_external_crash_reporter_path(
+            options, "./sentry_crash_reporter");
+#endif
+    }
+
     if (0 != sentry_init(options)) {
         return EXIT_FAILURE;
     }

include/sentry.h

@@ -1396,6 +1396,31 @@ SENTRY_API void sentry_options_set_handler_path(
 SENTRY_API void sentry_options_set_handler_path_n(
     sentry_options_t *opts, const char *path, size_t path_len);
 
+/**
+ * Sets the path to an external crash reporter executable, which can be used to
+ * display crash information to the user, collect user feedback, or perform
+ * other actions when a crash occurs.
+ *
+ * The external crash reporter is a user-defined executable, distinct from the
+ * system crash reporter, that is launched by the Native SDK upon a crash. It
+ * receives the path to the crash report as its only command-line argument and
+ * is responsible for submitting the crash report to Sentry. If using the Native
+ * SDK, this can be done using the `sentry_capture_envelope` function.
+ *
+ * A well-behaving external crash reporter should delete the crash report
+ * after handling it. As a safeguard, the Native SDK automatically removes
+ * crash reports older than one hour on startup to prevent filling up the disk
+ * with stale crash reports.
+ *
+ * The `path` parameter should use platform-specific filesystem encoding.
+ * On Windows, API users are encouraged to use
+ * `sentry_options_set_external_crash_reporter_pathw` instead.
+ */
+SENTRY_API void sentry_options_set_external_crash_reporter_path(
+    sentry_options_t *opts, const char *path);
+SENTRY_API void sentry_options_set_external_crash_reporter_path_n(
+    sentry_options_t *opts, const char *path, size_t path_len);
+
 /**
  * Sets the path to the Sentry Database Directory.
  *
@@ -1455,6 +1480,14 @@ SENTRY_API void sentry_options_set_handler_pathw(
 SENTRY_API void sentry_options_set_handler_pathw_n(
     sentry_options_t *opts, const wchar_t *path, size_t path_len);
 
+/**
+ * Wide char version of `sentry_options_set_external_crash_reporter_path`.
+ */
+SENTRY_API void sentry_options_set_external_crash_reporter_pathw(
+    sentry_options_t *opts, const wchar_t *path);
+SENTRY_API void sentry_options_set_external_crash_reporter_pathw_n(
+    sentry_options_t *opts, const wchar_t *path, size_t path_len);
+
 /**
  * Wide char version of `sentry_options_set_database_path`.
  */

src/backends/sentry_backend_breakpad.cpp

@@ -184,12 +184,14 @@ breakpad_backend_callback(const google_breakpad::MinidumpDescriptor &descriptor,
                 sentry__attachment_free(screenshot);
             }
 
-            // capture the envelope with the disk transport
-            sentry_transport_t *disk_transport
-                = sentry_new_disk_transport(options->run);
-            sentry__capture_envelope(disk_transport, envelope);
-            sentry__transport_dump_queue(disk_transport, options->run);
-            sentry_transport_free(disk_transport);
+            if (!sentry__launch_external_crash_reporter(envelope)) {
+                // capture the envelope with the disk transport
+                sentry_transport_t *disk_transport
+                    = sentry_new_disk_transport(options->run);
+                sentry__capture_envelope(disk_transport, envelope);
+                sentry__transport_dump_queue(disk_transport, options->run);
+                sentry_transport_free(disk_transport);
+            }
 
             // now that the envelope was written, we can remove the temporary
             // minidump file

src/backends/sentry_backend_crashpad.cpp

@@ -116,6 +116,7 @@ typedef struct {
     sentry_path_t *event_path;
     sentry_path_t *breadcrumb1_path;
     sentry_path_t *breadcrumb2_path;
+    sentry_path_t *external_report_path;
     size_t num_breadcrumbs;
     std::atomic<bool> crashed;
     std::atomic<bool> scope_flush;
@@ -188,7 +189,7 @@ crashpad_register_wer_module(
 #endif
 
 static void
-crashpad_backend_flush_scope_to_event(const sentry_path_t *event_path,
+flush_scope_to_event(const sentry_path_t *event_path,
     const sentry_options_t *options, sentry_value_t crash_event)
 {
     SENTRY_WITH_SCOPE (scope) {
@@ -212,6 +213,25 @@ crashpad_backend_flush_scope_to_event(const sentry_path_t *event_path,
     }
 }
 
+// Prepares an envelope with DSN, event ID, and session if available, for an
+// external crash reporter.
+static void
+flush_external_crash_report(
+    const sentry_options_t *options, const sentry_uuid_t *crash_event_id)
+{
+    sentry_envelope_t *envelope = sentry__envelope_new();
+    if (!envelope) {
+        return;
+    }
+    sentry__envelope_set_event_id(envelope, crash_event_id);
+    if (options->session) {
+        sentry__envelope_add_session(envelope, options->session);
+    }
+
+    sentry__run_write_external(options->run, envelope);
+    sentry_envelope_free(envelope);
+}
+
 // This function is necessary for macOS since it has no `FirstChanceHandler`.
 // but it is also necessary on Windows if the WER handler is enabled.
 // This means we have to continuously flush the scope on
@@ -244,7 +264,10 @@ crashpad_backend_flush_scope(
     sentry_value_set_by_key(
         event, "level", sentry__value_new_level(SENTRY_LEVEL_FATAL));
 
-    crashpad_backend_flush_scope_to_event(data->event_path, options, event);
+    flush_scope_to_event(data->event_path, options, event);
+    if (data->external_report_path) {
+        flush_external_crash_report(options, &data->crash_event_id);
+    }
     data->scope_flush.store(false, std::memory_order_release);
 #endif
 }
@@ -267,8 +290,10 @@ flush_scope_from_handler(
     }
 
     // now we are the sole flusher and can flush into the crash event
-    crashpad_backend_flush_scope_to_event(
-        state->event_path, options, crash_event);
+    flush_scope_to_event(state->event_path, options, crash_event);
+    if (state->external_report_path) {
+        flush_external_crash_report(options, &state->crash_event_id);
+    }
 }
 
 #    ifdef SENTRY_PLATFORM_WINDOWS
@@ -474,6 +499,22 @@ crashpad_backend_startup(
         sentry__path_free(screenshot_path);
     }
 
+    base::FilePath crash_reporter;
+    base::FilePath crash_envelope;
+    if (options->external_crash_reporter) {
+        char *filename
+            = sentry__uuid_as_filename(&data->crash_event_id, ".envelope");
+        data->external_report_path
+            = sentry__path_join_str(options->run->external_path, filename);
+        sentry_free(filename);
+
+        if (data->external_report_path) {
+            crash_reporter
+                = base::FilePath(options->external_crash_reporter->path);
+            crash_envelope = base::FilePath(data->external_report_path->path);
+        }
+    }
+
     std::vector<std::string> arguments { "--no-rate-limit" };
 
     // Initialize database first, flushing the consent later on as part of
@@ -501,7 +542,7 @@ crashpad_backend_startup(
         minidump_url ? minidump_url : "", proxy_url, annotations, arguments,
         /* restartable */ true,
         /* asynchronous_start */ false, attachments, screenshot,
-        options->crashpad_wait_for_upload);
+        options->crashpad_wait_for_upload, crash_reporter, crash_envelope);
     sentry_free(minidump_url);
 
 #ifdef SENTRY_PLATFORM_WINDOWS
@@ -614,6 +655,7 @@ crashpad_backend_free(sentry_backend_t *backend)
     sentry__path_free(data->event_path);
     sentry__path_free(data->breadcrumb1_path);
     sentry__path_free(data->breadcrumb2_path);
+    sentry__path_free(data->external_report_path);
     sentry_free(data);
 }
 

src/backends/sentry_backend_inproc.c

@@ -616,12 +616,14 @@ handle_ucontext(const sentry_ucontext_t *uctx)
                 sentry__attachment_free(screenshot);
             }
 
-            // capture the envelope with the disk transport
-            sentry_transport_t *disk_transport
-                = sentry_new_disk_transport(options->run);
-            sentry__capture_envelope(disk_transport, envelope);
-            sentry__transport_dump_queue(disk_transport, options->run);
-            sentry_transport_free(disk_transport);
+            if (!sentry__launch_external_crash_reporter(envelope)) {
+                // capture the envelope with the disk transport
+                sentry_transport_t *disk_transport
+                    = sentry_new_disk_transport(options->run);
+                sentry__capture_envelope(disk_transport, envelope);
+                sentry__transport_dump_queue(disk_transport, options->run);
+                sentry_transport_free(disk_transport);
+            }
         } else {
             SENTRY_DEBUG("event was discarded by the `on_crash` hook");
             sentry_value_decref(event);

src/sentry_core.c

@@ -11,6 +11,7 @@
 #include "sentry_logs.h"
 #include "sentry_options.h"
 #include "sentry_path.h"
+#include "sentry_process.h"
 #include "sentry_random.h"
 #include "sentry_scope.h"
 #include "sentry_session.h"
@@ -19,7 +20,9 @@
 #include "sentry_tracing.h"
 #include "sentry_transport.h"
 #include "sentry_tsan.h"
+#include "sentry_uuid.h"
 #include "sentry_value.h"
+#include "transports/sentry_disk_transport.h"
 
 #ifdef SENTRY_PLATFORM_WINDOWS
 #    include "sentry_os.h"
@@ -1493,6 +1496,48 @@ sentry_capture_feedback(sentry_value_t user_feedback)
     }
 }
 
+bool
+sentry__launch_external_crash_reporter(sentry_envelope_t *envelope)
+{
+    SENTRY_WITH_OPTIONS (options) {
+        if (!options->external_crash_reporter) {
+            return false;
+        }
+
+        sentry_uuid_t event_id = sentry__envelope_get_event_id(envelope);
+        char *envelope_filename
+            = sentry__uuid_as_filename(&event_id, ".envelope");
+        if (!envelope_filename) {
+            return false;
+        }
+
+        sentry_path_t *report_path = sentry__path_join_str(
+            options->run->external_path, envelope_filename);
+        if (!report_path) {
+            sentry_free(envelope_filename);
+            return false;
+        }
+
+        // capture the envelope with the disk transport
+        sentry_transport_t *disk_transport
+            = sentry_new_external_disk_transport(options->run);
+        if (!disk_transport) {
+            sentry__path_free(report_path);
+            sentry_free(envelope_filename);
+            return false;
+        }
+        sentry__capture_envelope(disk_transport, envelope);
+        sentry__transport_dump_queue(disk_transport, options->run);
+        sentry_transport_free(disk_transport);
+
+        sentry__process_spawn(
+            options->external_crash_reporter, report_path->path, NULL);
+        sentry__path_free(report_path);
+        sentry_free(envelope_filename);
+    }
+    return true;
+}
+
 int
 sentry_get_crashed_last_run(void)
 {

src/sentry_core.h

@@ -122,6 +122,8 @@ void sentry__options_unlock(void);
 
 void sentry__set_propagation_context(const char *key, sentry_value_t value);
 
+bool sentry__launch_external_crash_reporter(sentry_envelope_t *envelope);
+
 #define SENTRY_WITH_OPTIONS(Options)                                           \
     for (const sentry_options_t *Options = sentry__options_getref(); Options;  \
         sentry_options_free((sentry_options_t *)Options), Options = NULL)