Add exc_server_variants including UniversalMachExcServer and its test

util/mach/exc_server_variants.h

Index: util/mach/exc_server_variants.h
diff --git a/util/mach/exc_server_variants.h b/util/mach/exc_server_variants.h
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+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CRASHPAD_UTIL_MACH_EXC_SERVER_VARIANTS_H_
+#define CRASHPAD_UTIL_MACH_EXC_SERVER_VARIANTS_H_
+
+#include <mach/mach.h>
+
+#include "util/mach/mach_message_server.h"
+
+namespace crashpad {
+
+// Routines to provide a single unified front-end to the interfaces in
+// <mach/exc.defs> and <mach/mach_exc.defs>. The two interfaces are identical,
+// except that the latter allows for 64-bit exception codes, and is requested by
+// setting the MACH_EXCEPTION_CODES behavior bit associated with an exception
+// port.
+
+namespace internal {
+
+//! \brief A server interface for the `exc` Mach subsystem.
+class ExcServer : public MachMessageServer::Interface {
+ public:
+  //! \brief An interface that the different request messages that are a part of
+  //!     the `exc` Mach subsystem can be dispatched to.
+  class Interface {
+   public:
+    //! \brief Handles exceptions raised by `exception_raise()`.
+    //!
+    //! This behaves equivalently to a `catch_exception_raise()` function used
+    //! with `exc_server()`.
+    //!
+    //! \param[out] destroy_request `true` if the request message is to be
+    //!     destroyed even when this method returns success. See
+    //!     MachMessageServer::Interface.
+    virtual kern_return_t CatchExceptionRaise(
+        exception_handler_t exception_port,
+        thread_t thread,
+        task_t task,
+        exception_type_t exception,
+        const exception_data_type_t* code,
+        mach_msg_type_number_t code_count,
+        bool* destroy_request) = 0;
+
+    //! \brief Handles exceptions raised by `exception_raise_state()`.
+    //!
+    //! This behaves equivalently to a `catch_exception_raise_state()` function
+    //! used with `exc_server()`.
+    //!
+    //! There is no \a destroy_request parameter because, unlike
+    //! CatchExceptionRaise() and CatchExceptionRaiseStateIdentity(), the
+    //! request message is not complex (it does not carry the \a thread or \a
+    //! task port rights) and thus there is nothing to destroy.
+    virtual kern_return_t CatchExceptionRaiseState(
+        exception_handler_t exception_port,
+        exception_type_t exception,
+        const exception_data_type_t* code,
+        mach_msg_type_number_t code_count,
+        thread_state_flavor_t* flavor,
+        const natural_t* old_state,
+        mach_msg_type_number_t old_state_count,
+        thread_state_t new_state,
+        mach_msg_type_number_t* new_state_count) = 0;
+
+    //! \brief Handles exceptions raised by `exception_raise_state_identity()`.
+    //!
+    //! This behaves equivalently to a `catch_exception_raise_state_identity()`
+    //! function used with `exc_server()`.
+    //!
+    //! \param[out] destroy_request `true` if the request message is to be
+    //!     destroyed even when this method returns success. See
+    //!     MachMessageServer::Interface.
+    virtual kern_return_t CatchExceptionRaiseStateIdentity(
+        exception_handler_t exception_port,
+        thread_t thread,
+        task_t task,
+        exception_type_t exception,
+        const exception_data_type_t* code,
+        mach_msg_type_number_t code_count,
+        thread_state_flavor_t* flavor,
+        const natural_t* old_state,
+        mach_msg_type_number_t old_state_count,
+        thread_state_t new_state,
+        mach_msg_type_number_t* new_state_count,
+        bool* destroy_request) = 0;
+
+   protected:
+    ~Interface() {}
+  };
+
+  explicit ExcServer(Interface* interface);
+
+  // MachMessageServer::Interface:
+
+  virtual bool MachMessageServerFunction(
+      mach_msg_header_t* in_header,
+      mach_msg_header_t* out_header,
+      bool* destroy_complex_request) override;
+
+  virtual mach_msg_size_t MachMessageServerRequestSize() override;
+  virtual mach_msg_size_t MachMessageServerReplySize() override;
+
+ private:
+  Interface* interface_;  // weak
+};
+
+//! \brief A server interface for the `mach_exc` Mach subsystem.
+class MachExcServer : public MachMessageServer::Interface {
+ public:
+  //! \brief An interface that the different request messages that are a part of
+  //!     the `mach_exc` Mach subsystem can be dispatched to.
+  class Interface {
+   public:
+    //! \brief Handles exceptions raised by `mach_exception_raise()`.
+    //!
+    //! This behaves equivalently to a `catch_mach_exception_raise()` function
+    //! used with `mach_exc_server()`.
+    //!
+    //! \param[out] destroy_request `true` if the request message is to be
+    //!     destroyed even when this method returns success. See
+    //!     MachMessageServer::Interface.
+    virtual kern_return_t CatchMachExceptionRaise(
+        exception_handler_t exception_port,
+        thread_t thread,
+        task_t task,
+        exception_type_t exception,
+        const mach_exception_data_type_t* code,
+        mach_msg_type_number_t code_count,
+        bool* destroy_request) = 0;
+
+    //! \brief Handles exceptions raised by `mach_exception_raise_state()`.
+    //!
+    //! This behaves equivalently to a `catch_mach_exception_raise_state()`
+    //! function used with `mach_exc_server()`.
+    //!
+    //! There is no \a destroy_request parameter because, unlike
+    //! CatchMachExceptionRaise() and CatchMachExceptionRaiseStateIdentity(),
+    //! the request message is not complex (it does not carry the \a thread or
+    //! \a task port rights) and thus there is nothing to destroy.
+    virtual kern_return_t CatchMachExceptionRaiseState(
+        exception_handler_t exception_port,
+        exception_type_t exception,
+        const mach_exception_data_type_t* code,
+        mach_msg_type_number_t code_count,
+        thread_state_flavor_t* flavor,
+        const natural_t* old_state,
+        mach_msg_type_number_t old_state_count,
+        thread_state_t new_state,
+        mach_msg_type_number_t* new_state_count) = 0;
+
+    //! \brief Handles exceptions raised by
+    //!     `mach_exception_raise_state_identity()`.
+    //!
+    //! This behaves equivalently to a
+    //! `catch_mach_exception_raise_state_identity()` function used with
+    //! `mach_exc_server()`.
+    //!
+    //! \param[out] destroy_request `true` if the request message is to be
+    //!     destroyed even when this method returns success. See
+    //!     MachMessageServer::Interface.
+    virtual kern_return_t CatchMachExceptionRaiseStateIdentity(
+        exception_handler_t exception_port,
+        thread_t thread,
+        task_t task,
+        exception_type_t exception,
+        const mach_exception_data_type_t* code,
+        mach_msg_type_number_t code_count,
+        thread_state_flavor_t* flavor,
+        const natural_t* old_state,
+        mach_msg_type_number_t old_state_count,
+        thread_state_t new_state,
+        mach_msg_type_number_t* new_state_count,
+        bool* destroy_request) = 0;
+
+   protected:
+    ~Interface() {}
+  };
+
+  explicit MachExcServer(Interface* interface);
+
+  // MachMessageServer::Interface:
+
+  virtual bool MachMessageServerFunction(
+      mach_msg_header_t* in_header,
+      mach_msg_header_t* out_header,
+      bool* destroy_complex_request) override;
+
+  virtual mach_msg_size_t MachMessageServerRequestSize() override;
+  virtual mach_msg_size_t MachMessageServerReplySize() override;
+
+ private:
+  Interface* interface_;  // weak
+};
+
+//! \brief A server interface for the `exc` Mach subsystem, simplified to have
+//!     only a single interface method needing implementation.
+class SimplifiedExcServer : public ExcServer, public ExcServer::Interface {
+ public:
+  //! \brief An interface that the different request messages that are a part of
+  //!     the `exc` Mach subsystem can be dispatched to.
+  class Interface {
+   public:
+    //! \brief Handles exceptions raised by `exception_raise()`,
+    //!     `exception_raise_state()`, and `exception_raise_state_identity()`.
+    //!
+    //! For convenience in implementation, these different “behaviors” of
+    //! exception messages are all mapped to a single interface method. The
+    //! exception’s original “behavior” is specified in the \a behavior
+    //! parameter. Only parameters that were supplied in the request message
+    //! are populated, other parameters are set to reasonable default values.
+    //!
+    //! The meanings of most parameters are identical to that of
+    //! ExcServer::Interface::CatchExceptionRaiseStateIdentity().
+    //!
+    //! \param[in] behavior `EXCEPTION_DEFAULT`, `EXCEPTION_STATE`, or
+    //!     `EXCEPTION_STATE_IDENTITY`, identifying which exception request
+    //!     message was processed and thus which other parameters are valid.
+    virtual kern_return_t CatchException(
+        exception_behavior_t behavior,
+        exception_handler_t exception_port,
+        thread_t thread,
+        task_t task,
+        exception_type_t exception,
+        const exception_data_type_t* code,
+        mach_msg_type_number_t code_count,
+        thread_state_flavor_t* flavor,
+        const natural_t* old_state,
+        mach_msg_type_number_t old_state_count,
+        thread_state_t new_state,
+        mach_msg_type_number_t* new_state_count,
+        bool* destroy_complex_request) = 0;
+
+   protected:
+    ~Interface() {}
+  };
+
+  explicit SimplifiedExcServer(Interface* interface);
+
+  // ExcServer::Interface:
+
+  virtual kern_return_t CatchExceptionRaise(
+      exception_handler_t exception_port,
+      thread_t thread,
+      task_t task,
+      exception_type_t exception,
+      const exception_data_type_t* code,
+      mach_msg_type_number_t code_count,
+      bool* destroy_request) override;
+  virtual kern_return_t CatchExceptionRaiseState(
+      exception_handler_t exception_port,
+      exception_type_t exception,
+      const exception_data_type_t* code,
+      mach_msg_type_number_t code_count,
+      thread_state_flavor_t* flavor,
+      const natural_t* old_state,
+      mach_msg_type_number_t old_state_count,
+      thread_state_t new_state,
+      mach_msg_type_number_t* new_state_count) override;
+  virtual kern_return_t CatchExceptionRaiseStateIdentity(
+      exception_handler_t exception_port,
+      thread_t thread,
+      task_t task,
+      exception_type_t exception,
+      const exception_data_type_t* code,
+      mach_msg_type_number_t code_count,
+      thread_state_flavor_t* flavor,
+      const natural_t* old_state,
+      mach_msg_type_number_t old_state_count,
+      thread_state_t new_state,
+      mach_msg_type_number_t* new_state_count,
+      bool* destroy_request) override;
+
+ private:
+  Interface* interface_;  // weak
+};
+
+//! \brief A server interface for the `mach_exc` Mach subsystem, simplified to
+//!     have only a single interface method needing implementation.
+class SimplifiedMachExcServer : public MachExcServer,
+                                public MachExcServer::Interface {
+ public:
+  //! \brief An interface that the different request messages that are a part of
+  //!     the `mach_exc` Mach subsystem can be dispatched to.
+  class Interface {
+   public:
+    //! \brief Handles exceptions raised by `mach_exception_raise()`,
+    //!     `mach_exception_raise_state()`, and
+    //!     `mach_exception_raise_state_identity()`.
+    //!
+    //! When used with UniversalMachExcServer, this also handles exceptions
+    //! raised by `exception_raise()`, `exception_raise_state()`, and
+    //! `exception_raise_state_identity()`.
+    //!
+    //! For convenience in implementation, these different “behaviors” of
+    //! exception messages are all mapped to a single interface method. The
+    //! exception’s original “behavior” is specified in the \a behavior
+    //! parameter. Only parameters that were supplied in the request message
+    //! are populated, other parameters are set to reasonable default values.
+    //!
+    //! The meanings of most parameters are identical to that of
+    //! MachExcServer::Interface::CatchMachExceptionRaiseStateIdentity().
+    //!
+    //! \param[in] behavior `MACH_EXCEPTION_CODES | EXCEPTION_DEFAULT`,
+    //!     `MACH_EXCEPTION_CODES | EXCEPTION_STATE`, or
+    //!     `MACH_EXCEPTION_CODES | EXCEPTION_STATE_IDENTITY`, identifying which
+    //!     exception request message was processed and thus which other
+    //!     parameters are valid. When used with UniversalMachExcServer, \a
+    //!     behavior can also be `EXCEPTION_DEFAULT`, `EXCEPTION_STATE`, or
+    //!     `EXCEPTION_STATE_IDENTITY`.
+    virtual kern_return_t CatchMachException(
+        exception_behavior_t behavior,
+        exception_handler_t exception_port,
+        thread_t thread,
+        task_t task,
+        exception_type_t exception,
+        const mach_exception_data_type_t* code,
+        mach_msg_type_number_t code_count,
+        thread_state_flavor_t* flavor,
+        const natural_t* old_state,
+        mach_msg_type_number_t old_state_count,
+        thread_state_t new_state,
+        mach_msg_type_number_t* new_state_count,
+        bool* destroy_complex_request) = 0;
+
+   protected:
+    ~Interface() {}
+  };
+
+  explicit SimplifiedMachExcServer(Interface* interface);
+
+  // MachExcServer::Interface:
+
+  virtual kern_return_t CatchMachExceptionRaise(
+      exception_handler_t exception_port,
+      thread_t thread,
+      task_t task,
+      exception_type_t exception,
+      const mach_exception_data_type_t* code,
+      mach_msg_type_number_t code_count,
+      bool* destroy_request) override;
+  virtual kern_return_t CatchMachExceptionRaiseState(
+      exception_handler_t exception_port,
+      exception_type_t exception,
+      const mach_exception_data_type_t* code,
+      mach_msg_type_number_t code_count,
+      thread_state_flavor_t* flavor,
+      const natural_t* old_state,
+      mach_msg_type_number_t old_state_count,
+      thread_state_t new_state,
+      mach_msg_type_number_t* new_state_count) override;
+  virtual kern_return_t CatchMachExceptionRaiseStateIdentity(
+      exception_handler_t exception_port,
+      thread_t thread,
+      task_t task,
+      exception_type_t exception,
+      const mach_exception_data_type_t* code,
+      mach_msg_type_number_t code_count,
+      thread_state_flavor_t* flavor,
+      const natural_t* old_state,
+      mach_msg_type_number_t old_state_count,
+      thread_state_t new_state,
+      mach_msg_type_number_t* new_state_count,
+      bool* destroy_request) override;
+
+ private:
+  Interface* interface_;  // weak
+};
+
+}  // namespace internal
+
+//! \brief A server interface for the `exc` and `mach_exc` Mach subsystems,
+//!     unified to handle exceptions delivered to either subsystem, and
+//!     simplified to have only a single interface method needing
+//!     implementation.
+//!
+//! UniversalMachExcServer operates by translating messages received in the
+//! `exc` subsystem to a variant that is compatible with the `mach_exc`
+//! subsystem. This involves changing the format of \a code, the exception code
+//! field, from `exception_data_type_t` to `mach_exception_data_type_t`.
+//! This is achieved by implementing SimplifiedExcServer::Interface and having
+//! it forward translated messages to SimplifiedMachExcServer::Interface, which
+//! is left unimplemented here so that users of this class can provide their own
+//! implementations.
+class UniversalMachExcServer
+    : public MachMessageServer::Interface,
+      public internal::SimplifiedExcServer::Interface,
+      public internal::SimplifiedMachExcServer::Interface {
+ public:
+  UniversalMachExcServer();
+
+  // MachMessageServer::Interface:
+
+  virtual bool MachMessageServerFunction(
+      mach_msg_header_t* in_header,
+      mach_msg_header_t* out_header,
+      bool* destroy_complex_request) override;
+
+  virtual mach_msg_size_t MachMessageServerRequestSize() override;
+  virtual mach_msg_size_t MachMessageServerReplySize() override;
+
+  // internal::SimplifiedExcServer::Interface:
+
+  virtual kern_return_t CatchException(
+      exception_behavior_t behavior,
+      exception_handler_t exception_port,
+      thread_t thread,
+      task_t task,
+      exception_type_t exception,
+      const exception_data_type_t* code,
+      mach_msg_type_number_t code_count,
+      thread_state_flavor_t* flavor,
+      const natural_t* old_state,
+      mach_msg_type_number_t old_state_count,
+      thread_state_t new_state,
+      mach_msg_type_number_t* new_state_count,
+      bool* destroy_complex_request) override;
+
+ private:
+  internal::SimplifiedExcServer exc_server_;
+  internal::SimplifiedMachExcServer mach_exc_server_;
+};
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_UTIL_MACH_EXC_SERVER_VARIANTS_H_