Creating minidump for uncaught exception on iOS.

 This CL adds a minidump_generator that can write a minidump from a NSException
on iOS on an ARM cpu.

 This CL also install an uncaught exception handler on iOS, and use the
previous generator to write minidumps for any uncaught exception.
Review URL: https://breakpad.appspot.com/347001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@916 4c0a9323-5329-0410-9bdc-e9ce6186880e

2 files changed, 228 insertions, 0 deletions

diff --git a/src/client/ios/handler/ios_exception_minidump_generator.h b/src/client/ios/handler/ios_exception_minidump_generator.h
new file mode 100644
index 00000000..59f24819
--- /dev/null
+++ b/src/client/ios/handler/ios_exception_minidump_generator.h
@@ -0,0 +1,64 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// ios_exception_minidump_generator.h:  Create a fake minidump from a
+// NSException.
+
+#ifndef CLIENT_IOS_HANDLER_IOS_EXCEPTION_MINIDUMP_GENERATOR_H_
+#define CLIENT_IOS_HANDLER_IOS_EXCEPTION_MINIDUMP_GENERATOR_H_
+
+#include <Foundation/Foundation.h>
+
+#include "client/mac/handler/minidump_generator.h"
+
+namespace google_breakpad {
+
+class IosExceptionMinidumpGenerator : public MinidumpGenerator {
+ public:
+  explicit IosExceptionMinidumpGenerator(NSException *exception);
+  virtual ~IosExceptionMinidumpGenerator();
+
+ protected:
+  virtual bool WriteExceptionStream(MDRawDirectory *exception_stream);
+  virtual bool WriteThreadStream(mach_port_t thread_id, MDRawThread *thread);
+
+ private:
+
+  // Get the crashing program counter from the exception.
+  uint32_t GetPCFromException();
+
+  // Write a virtual thread context for the crashing site.
+  bool WriteCrashingContext(MDLocationDescriptor *register_location);
+
+  NSArray *return_addresses_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_IOS_HANDLER_IOS_EXCEPTION_MINIDUMP_GENERATOR_H_
diff --git a/src/client/ios/handler/ios_exception_minidump_generator.mm b/src/client/ios/handler/ios_exception_minidump_generator.mm
new file mode 100644
index 00000000..6b8b1064
--- /dev/null
+++ b/src/client/ios/handler/ios_exception_minidump_generator.mm
@@ -0,0 +1,164 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "client/ios/handler/ios_exception_minidump_generator.h"
+
+#include "processor/scoped_ptr.h"
+
+namespace {
+
+const uint32_t kExpectedFinalFp = 4;
+const uint32_t kExpectedFinalSp = 0;
+const int kExceptionType = EXC_SOFTWARE;
+const int kExceptionCode = 0xDEADBEEF;
+
+// Append the given 4 bytes value to the sp position of the stack represented
+// by memory.
+void AppendToMemory(uint8_t *memory, uint32_t sp, uint32_t data) {
+  assert(sizeof(data) == 4);
+  memcpy(memory + sp, &data, sizeof(data));
+}
+
+}  // namespace
+
+namespace google_breakpad {
+
+IosExceptionMinidumpGenerator::IosExceptionMinidumpGenerator(
+    NSException *exception)
+    : MinidumpGenerator(mach_task_self(), 0) {
+  return_addresses_ = [[exception callStackReturnAddresses] retain];
+  SetExceptionInformation(kExceptionType,
+                          kExceptionCode,
+                          0,
+                          pthread_mach_thread_np(pthread_self()));
+}
+
+IosExceptionMinidumpGenerator::~IosExceptionMinidumpGenerator() {
+  [return_addresses_ release];
+}
+
+bool IosExceptionMinidumpGenerator::WriteCrashingContext(
+    MDLocationDescriptor *register_location) {
+#ifdef HAS_ARM_SUPPORT
+  TypedMDRVA<MDRawContextARM> context(&writer_);
+  if (!context.Allocate())
+    return false;
+  *register_location = context.location();
+  MDRawContextARM *context_ptr = context.get();
+  memset(context_ptr, 0, sizeof(MDRawContextARM));
+  context_ptr->context_flags = MD_CONTEXT_ARM_FULL;
+  context_ptr->iregs[7] = kExpectedFinalFp;  // FP
+  context_ptr->iregs[13] = kExpectedFinalSp;  // SP
+  uint32_t pc = GetPCFromException();
+  context_ptr->iregs[14] = pc;  // LR
+  context_ptr->iregs[15] = pc;  // PC
+  return true;
+#else
+  assert(false);
+  return false;
+#endif
+}
+
+uint32_t IosExceptionMinidumpGenerator::GetPCFromException() {
+  return [[return_addresses_ objectAtIndex:0] unsignedIntegerValue];
+}
+
+bool IosExceptionMinidumpGenerator::WriteExceptionStream(
+    MDRawDirectory *exception_stream) {
+#ifdef HAS_ARM_SUPPORT
+  TypedMDRVA<MDRawExceptionStream> exception(&writer_);
+
+  if (!exception.Allocate())
+    return false;
+
+  exception_stream->stream_type = MD_EXCEPTION_STREAM;
+  exception_stream->location = exception.location();
+  MDRawExceptionStream *exception_ptr = exception.get();
+  exception_ptr->thread_id = pthread_mach_thread_np(pthread_self());
+
+  // This naming is confusing, but it is the proper translation from
+  // mach naming to minidump naming.
+  exception_ptr->exception_record.exception_code = kExceptionType;
+  exception_ptr->exception_record.exception_flags = kExceptionCode;
+
+  if (!WriteCrashingContext(&exception_ptr->thread_context))
+    return false;
+
+  exception_ptr->exception_record.exception_address = GetPCFromException();
+  return true;
+#else
+  return MinidumpGenerator::WriteExceptionStream(exception_stream);
+#endif
+}
+
+bool IosExceptionMinidumpGenerator::WriteThreadStream(mach_port_t thread_id,
+                                                      MDRawThread *thread) {
+#ifdef HAS_ARM_SUPPORT
+  if (pthread_mach_thread_np(pthread_self()) != thread_id)
+    return MinidumpGenerator::WriteThreadStream(thread_id, thread);
+
+  size_t frame_count = [return_addresses_ count];
+  UntypedMDRVA memory(&writer_);
+  size_t size = 8 * (frame_count - 1) + 4;
+  if (!memory.Allocate(size))
+    return false;
+  scoped_array<uint8_t> stack_memory(new uint8_t[size]);
+  uint32_t sp = size - 4;
+  uint32_t fp = 0;
+  uint32_t lr = [[return_addresses_ lastObject] unsignedIntegerValue];
+  for (int current_frame = frame_count - 2;
+       current_frame >= 0;
+       --current_frame) {
+    AppendToMemory(stack_memory.get(), sp, fp);
+    sp -= 4;
+    fp = sp;
+    AppendToMemory(stack_memory.get(), sp, lr);
+    sp -= 4;
+    lr = [[return_addresses_ objectAtIndex:current_frame] unsignedIntegerValue];
+  }
+  if (!memory.Copy(stack_memory.get(), size))
+    return false;
+  assert(sp == kExpectedFinalSp);
+  assert(fp == kExpectedFinalFp);
+  assert(lr == GetPCFromException());
+  thread->stack.start_of_memory_range = sp;
+  thread->stack.memory = memory.location();
+  memory_blocks_.push_back(thread->stack);
+
+  if (!WriteCrashingContext(&thread->thread_context))
+    return false;
+
+  thread->thread_id = thread_id;
+  return true;
+#else
+  return MinidumpGenerator::WriteThreadStream(thread_id, thread);
+#endif
+}
+
+}  // namespace google_breakpad