ios: Move and update ObjcExceptionPreprocessor.
More cleanly integration the ObjExceptionPreprocessor with the
Crashpad client and in process handler, to record bought
'caught' and 'uncaught' NSExceptions.
Bug: crashpad: 31
Change-Id: I912a407cfde4ea7c0e4c4506e07dff35c77fe489
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/2920851
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
GitOrigin-RevId: e47918b80abf61c9d013012b2df1769e0c0b18d2
diff --git a/client/BUILD.gn b/client/BUILD.gn
index 5cf5532..aa1eaaa 100644
--- a/client/BUILD.gn
+++ b/client/BUILD.gn
@@ -33,6 +33,8 @@
if (crashpad_is_ios) {
sources += [
"crashpad_client_ios.cc",
+ "ios_handler/exception_processor.h",
+ "ios_handler/exception_processor.mm",
"simulate_crash_ios.h",
]
}
@@ -160,7 +162,10 @@
}
if (crashpad_is_ios) {
- sources += [ "crashpad_client_ios_test.mm" ]
+ sources += [
+ "crashpad_client_ios_test.mm",
+ "ios_handler/exception_processor_test.mm",
+ ]
sources -= [
"annotation_list_test.cc",
"annotation_test.cc",
diff --git a/client/crashpad_client_ios.cc b/client/crashpad_client_ios.cc
index a8ef224..f53a6d5 100644
--- a/client/crashpad_client_ios.cc
+++ b/client/crashpad_client_ios.cc
@@ -22,7 +22,7 @@
#include "base/logging.h"
#include "base/mac/mach_logging.h"
#include "base/mac/scoped_mach_port.h"
-#include "util/ios/exception_processor.h"
+#include "client/ios_handler/exception_processor.h"
#include "util/ios/ios_system_data_collector.h"
#include "util/mach/exc_server_variants.h"
#include "util/mach/exception_ports.h"
@@ -38,7 +38,9 @@
namespace {
// A base class for signal handler and Mach exception server.
-class CrashHandler : public Thread, public UniversalMachExcServer::Interface {
+class CrashHandler : public Thread,
+ public UniversalMachExcServer::Interface,
+ public ObjcExceptionDelegate {
public:
static CrashHandler* Get() {
static CrashHandler* instance = new CrashHandler();
@@ -188,6 +190,26 @@
Signals::RestoreHandlerAndReraiseSignalOnReturn(siginfo, &old_action_);
}
+ void HandleUncaughtNSException(const uint64_t* frames,
+ const size_t num_frames) override {
+ // TODO(justincohen): Call into in_process_handler.
+
+ // After uncaught exceptions are reported, the system immediately triggers a
+ // call to std::terminate()/abort(). Remove the abort handler so a second
+ // dump isn't generated.
+ CHECK(Signals::InstallDefaultHandler(SIGABRT));
+ }
+
+ void HandleUncaughtNSExceptionWithContext(
+ NativeCPUContext* context) override {
+ // TODO(justincohen): Call into in_process_handler.
+
+ // After uncaught exceptions are reported, the system immediately triggers a
+ // call to std::terminate()/abort(). Remove the abort handler so a second
+ // dump isn't generated.
+ CHECK(Signals::InstallDefaultHandler(SIGABRT));
+ }
+
base::mac::ScopedMachReceiveRight exception_port_;
ExceptionPorts::ExceptionHandlerVector original_handlers_;
struct sigaction old_action_ = {};
@@ -208,10 +230,10 @@
const base::FilePath& database,
const std::string& url,
const std::map<std::string, std::string>& annotations) {
- InstallObjcExceptionPreprocessor();
CrashHandler* crash_handler = CrashHandler::Get();
DCHECK(crash_handler);
+ InstallObjcExceptionPreprocessor(crash_handler);
crash_handler->Initialize();
}
diff --git a/util/ios/exception_processor.h b/client/ios_handler/exception_processor.h
similarity index 60%
rename from util/ios/exception_processor.h
rename to client/ios_handler/exception_processor.h
index 76a8c8b..7318e21 100644
--- a/util/ios/exception_processor.h
+++ b/client/ios_handler/exception_processor.h
@@ -15,8 +15,35 @@
#ifndef CRASHPAD_UTIL_IOS_EXCEPTION_PROCESSOR_H_
#define CRASHPAD_UTIL_IOS_EXCEPTION_PROCESSOR_H_
+#include <vector>
+
+#include "util/misc/capture_context.h"
+
namespace crashpad {
+//! \brief An interface for notifying the CrashpadClient of NSExceptions.
+class ObjcExceptionDelegate {
+ public:
+ //! \brief The exception processor detected an exception as it was thrown and
+ //! captured the cpu context.
+ //!
+ //! \param context The cpu context of the thread throwing an exception.
+ virtual void HandleUncaughtNSExceptionWithContext(
+ NativeCPUContext* context) = 0;
+
+ //! \brief The exception processor did not detect the exception as it was
+ //! thrown, and instead caught the exception via the
+ //! NSUncaughtExceptionHandler.
+ //!
+ //! \param frames An array of call stack frame addresses.
+ //! \param num_frames The number of frames in |frames|.
+ virtual void HandleUncaughtNSException(const uint64_t* frames,
+ const size_t num_frames) = 0;
+
+ protected:
+ ~ObjcExceptionDelegate() {}
+};
+
//! \brief Installs the Objective-C exception preprocessor.
//!
//! When code raises an Objective-C exception, unwind the stack looking for
@@ -30,7 +57,7 @@
//!
//! This should be installed at the same time the CrashpadClient installs the
//! signal handler. It should only be installed once.
-void InstallObjcExceptionPreprocessor();
+void InstallObjcExceptionPreprocessor(ObjcExceptionDelegate* delegate);
} // namespace crashpad
diff --git a/util/ios/exception_processor.mm b/client/ios_handler/exception_processor.mm
similarity index 67%
rename from util/ios/exception_processor.mm
rename to client/ios_handler/exception_processor.mm
index 2b2857e..d8c94e5 100644
--- a/util/ios/exception_processor.mm
+++ b/client/ios_handler/exception_processor.mm
@@ -12,7 +12,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.
-#include "util/ios/exception_processor.h"
+#include "client/ios_handler/exception_processor.h"
#include <Availability.h>
#import <Foundation/Foundation.h>
@@ -35,10 +35,15 @@
#include <typeinfo>
#include "base/bit_cast.h"
+#include "base/format_macros.h"
#include "base/logging.h"
#include "base/memory/free_deleter.h"
+#include "base/numerics/safe_conversions.h"
+#include "base/strings/stringprintf.h"
#include "base/strings/sys_string_conversions.h"
#include "build/build_config.h"
+#include "client/annotation.h"
+#include "client/simulate_crash_ios.h"
namespace {
@@ -80,20 +85,101 @@
_Unwind_Exception unwindHeader;
};
-objc_exception_preprocessor g_next_preprocessor;
-bool g_exception_preprocessor_installed;
+int LoggingUnwStep(unw_cursor_t* cursor) {
+ int rv = unw_step(cursor);
+ if (rv < 0) {
+ LOG(ERROR) << "unw_step: " << rv;
+ }
+ return rv;
+}
-void TerminatingFromUncaughtNSException(id exception, const char* sinkhole) {
- // TODO(justincohen): This is incomplete, as the signal handler will not have
- // access to the exception name and reason. Pass that along somehow here.
- NSString* exception_message_ns = [NSString
- stringWithFormat:@"%@: %@", [exception name], [exception reason]];
- std::string exception_message = base::SysNSStringToUTF8(exception_message_ns);
- LOG(INFO) << "Terminating from Objective-C exception: " << exception_message
- << " with sinkhole: " << sinkhole;
- // TODO(justincohen): This is temporary, as crashpad can capture this
- // exception directly instead.
- std::terminate();
+std::string FormatStackTrace(const std::vector<uint64_t>& addresses,
+ size_t max_length) {
+ std::string stack_string;
+ for (uint64_t address : addresses) {
+ std::string address_string = base::StringPrintf("0x%" PRIx64, address);
+ if (stack_string.size() + address_string.size() > max_length)
+ break;
+ stack_string += address_string + " ";
+ }
+
+ if (!stack_string.empty() && stack_string.back() == ' ') {
+ stack_string.resize(stack_string.size() - 1);
+ }
+
+ return stack_string;
+}
+
+std::string GetTraceString() {
+ std::vector<uint64_t> addresses;
+ unw_context_t context;
+ unw_getcontext(&context);
+ unw_cursor_t cursor;
+ unw_init_local(&cursor, &context);
+ while (LoggingUnwStep(&cursor) > 0) {
+ unw_word_t ip = 0;
+ unw_get_reg(&cursor, UNW_REG_IP, &ip);
+ addresses.push_back(ip);
+ }
+ return FormatStackTrace(addresses, 1024);
+}
+
+crashpad::ObjcExceptionDelegate* g_exception_delegate;
+objc_exception_preprocessor g_next_preprocessor;
+NSUncaughtExceptionHandler* g_next_uncaught_exception_handler;
+
+static void SetNSExceptionAnnotations(id exception,
+ std::string& name,
+ std::string& reason) {
+ name = base::SysNSStringToUTF8([exception name]);
+ reason = base::SysNSStringToUTF8([exception reason]);
+ static crashpad::StringAnnotation<256> nameKey("exceptionName");
+ nameKey.Set(name);
+ static crashpad::StringAnnotation<512> reasonKey("exceptionReason");
+ reasonKey.Set(reason);
+}
+
+static void ObjcUncaughtExceptionHandler(NSException* exception) {
+ std::string name, reason;
+ SetNSExceptionAnnotations(exception, name, reason);
+ NSArray<NSNumber*>* addressArray = [exception callStackReturnAddresses];
+ if ([addressArray count] > 0) {
+ static crashpad::StringAnnotation<256> nameKey("UncaughtNSException");
+ nameKey.Set("true");
+ std::vector<uint64_t> addresses;
+ NSArray<NSNumber*>* addressArray = [exception callStackReturnAddresses];
+ for (NSNumber* address in addressArray)
+ addresses.push_back([address unsignedLongLongValue]);
+ g_exception_delegate->HandleUncaughtNSException(&addresses[0],
+ addresses.size());
+ } else {
+ LOG(WARNING) << "Uncaught Objective-C exception name: " << name
+ << " reason: " << reason << " with no "
+ << " -callStackReturnAddresses.";
+ crashpad::NativeCPUContext cpu_context;
+ crashpad::CaptureContext(&cpu_context);
+ g_exception_delegate->HandleUncaughtNSExceptionWithContext(&cpu_context);
+ }
+}
+
+// This function is used to make it clear to the crash processor that an
+// uncaught NSException was recorded here.
+static __attribute__((noinline)) id HANDLE_UNCAUGHT_NSEXCEPTION(
+ id exception,
+ const char* sinkhole) {
+ std::string name, reason;
+ SetNSExceptionAnnotations(exception, name, reason);
+ LOG(WARNING) << "Handling Objective-C exception name: " << name
+ << " reason: " << reason << " with sinkhole: " << sinkhole;
+ crashpad::NativeCPUContext cpu_context;
+ crashpad::CaptureContext(&cpu_context);
+ g_exception_delegate->HandleUncaughtNSExceptionWithContext(&cpu_context);
+
+ // Remove the uncaught exception handler so we don't record this twice.
+ NSSetUncaughtExceptionHandler(g_next_uncaught_exception_handler);
+ g_next_uncaught_exception_handler = nullptr;
+
+ return g_next_preprocessor ? g_next_preprocessor(exception) : exception;
}
// Returns true if |path| equals |sinkhole| on device. Simulator paths prepend
@@ -113,15 +199,25 @@
#endif
}
-int LoggingUnwStep(unw_cursor_t* cursor) {
- int rv = unw_step(cursor);
- if (rv < 0) {
- LOG(ERROR) << "unw_step: " << rv;
- }
- return rv;
-}
-
id ObjcExceptionPreprocessor(id exception) {
+ static bool seen_first_exception;
+
+ static crashpad::StringAnnotation<256> firstexception("firstexception");
+ static crashpad::StringAnnotation<256> lastexception("lastexception");
+ static crashpad::StringAnnotation<1024> firstexception_bt(
+ "firstexception_bt");
+ static crashpad::StringAnnotation<1024> lastexception_bt("lastexception_bt");
+ auto* key = seen_first_exception ? &lastexception : &firstexception;
+ auto* bt_key = seen_first_exception ? &lastexception_bt : &firstexception_bt;
+ NSString* value = [NSString
+ stringWithFormat:@"%@ reason %@", [exception name], [exception reason]];
+ key->Set(base::SysNSStringToUTF8(value));
+
+ // This exception preprocessor runs prior to the one in libobjc, which sets
+ // the -[NSException callStackReturnAddresses].
+ bt_key->Set(GetTraceString());
+ seen_first_exception = true;
+
// Unwind the stack looking for any exception handlers. If an exception
// handler is encountered, test to see if it is a function known to catch-
// and-rethrow as a "top-level" exception handler. Various routines in
@@ -229,10 +325,13 @@
"CFRunLoopRunSpecific",
"_CFXNotificationPost",
"__NSFireDelayedPerform",
+ // If this exception is going to end up at EHFrame, record the uncaught
+ // exception instead.
+ "_ZN4base3mac15CallWithEHFrameEU13block_pointerFvvE",
};
for (const char* sinkhole : kExceptionSymbolNameSinkholes) {
if (strcmp(sinkhole, proc_name) == 0) {
- TerminatingFromUncaughtNSException(exception, sinkhole);
+ return HANDLE_UNCAUGHT_NSEXCEPTION(exception, sinkhole);
}
}
@@ -257,7 +356,7 @@
0) {
for (const char* sinkhole : kExceptionLibraryPathSinkholes) {
if (ModulePathMatchesSinkhole(dl_info.dli_fname, sinkhole)) {
- TerminatingFromUncaughtNSException(exception, sinkhole);
+ return HANDLE_UNCAUGHT_NSEXCEPTION(exception, sinkhole);
}
}
}
@@ -305,7 +404,7 @@
reinterpret_cast<unw_word_t>(gesture_environment_min_imp) &&
caller_frame_info.start_ip <=
reinterpret_cast<unw_word_t>(gesture_environment_max_imp)) {
- TerminatingFromUncaughtNSException(exception,
+ return HANDLE_UNCAUGHT_NSEXCEPTION(exception,
"_UIGestureEnvironmentUpdate");
}
}
@@ -319,37 +418,43 @@
// If no handler is found, __cxa_throw would call failed_throw and terminate.
// See:
// https://github.com/llvm/llvm-project/blob/c5d2746fbea7/libcxxabi/src/cxa_exception.cpp
- // __cxa_throw. Instead, terminate via TerminatingFromUncaughtNSException so
- // the exception name and reason are properly recorded.
+ // __cxa_throw. Instead, call HANDLE_UNCAUGHT_NSEXCEPTION so the exception
+ // name and reason are properly recorded.
if (!handler_found) {
- TerminatingFromUncaughtNSException(exception, "__cxa_throw");
+ return HANDLE_UNCAUGHT_NSEXCEPTION(exception, "__cxa_throw");
}
// Forward to the next preprocessor.
- if (g_next_preprocessor)
- return g_next_preprocessor(exception);
-
- return exception;
+ return g_next_preprocessor ? g_next_preprocessor(exception) : exception;
}
} // namespace
namespace crashpad {
-void InstallObjcExceptionPreprocessor() {
- DCHECK(!g_exception_preprocessor_installed);
+void InstallObjcExceptionPreprocessor(ObjcExceptionDelegate* delegate) {
+ DCHECK(!g_next_preprocessor);
+ // Preprocessor.
g_next_preprocessor =
objc_setExceptionPreprocessor(&ObjcExceptionPreprocessor);
- g_exception_preprocessor_installed = true;
+
+ // Uncaught processor.
+ g_exception_delegate = delegate;
+ g_next_uncaught_exception_handler = NSGetUncaughtExceptionHandler();
+ NSSetUncaughtExceptionHandler(&ObjcUncaughtExceptionHandler);
}
void UninstallObjcExceptionPreprocessor() {
- DCHECK(g_exception_preprocessor_installed);
+ DCHECK(g_next_preprocessor);
objc_setExceptionPreprocessor(g_next_preprocessor);
+ g_exception_delegate = nullptr;
+
+ NSSetUncaughtExceptionHandler(g_next_uncaught_exception_handler);
+ g_next_uncaught_exception_handler = nullptr;
+
g_next_preprocessor = nullptr;
- g_exception_preprocessor_installed = false;
}
} // namespace crashpad
diff --git a/util/ios/exception_processor_test.mm b/client/ios_handler/exception_processor_test.mm
similarity index 100%
rename from util/ios/exception_processor_test.mm
rename to client/ios_handler/exception_processor_test.mm
diff --git a/util/BUILD.gn b/util/BUILD.gn
index dfb1a9a..4f28414 100644
--- a/util/BUILD.gn
+++ b/util/BUILD.gn
@@ -378,8 +378,6 @@
if (crashpad_is_ios) {
sources += [
- "ios/exception_processor.h",
- "ios/exception_processor.mm",
"ios/ios_intermediate_dump_data.cc",
"ios/ios_intermediate_dump_data.h",
"ios/ios_intermediate_dump_format.h",
@@ -807,7 +805,6 @@
if (crashpad_is_ios) {
sources += [
- "ios/exception_processor_test.mm",
"ios/ios_intermediate_dump_reader_test.cc",
"ios/ios_intermediate_dump_writer_test.cc",
"ios/scoped_vm_read_test.cc",
