// Copyright 2014 The Crashpad Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef CRASHPAD_UTIL_MACH_EXCEPTION_PORTS_H_
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#define CRASHPAD_UTIL_MACH_EXCEPTION_PORTS_H_
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#include <mach/mach.h>
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#include <vector>
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#include "base/macros.h"
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namespace crashpad {
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//! \brief A better interface to `*_get_exception_ports()` and
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//! `*_set_exception_ports()`.
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//!
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//! The same generic interface can be used to operate on host, task, and thread
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//! exception ports. The “get” interface is superior to the system’s native
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//! interface because it keeps related data about a single exception handler
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//! together in one struct, rather than separating it into four parallel arrays.
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class ExceptionPorts {
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public:
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//! \brief Various entities which can have their own exception ports set.
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enum TargetType {
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//! \brief The host exception target.
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//!
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//! `host_get_exception_ports()` and `host_set_exception_ports()` will be
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//! used. If no target port is explicitly provided, `mach_host_self()` will
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//! be used as the target port. `mach_host_self()` is the only target port
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//! for this type that is expected to function properly.
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//!
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//! \note Operations on this target type are not expected to succeed as
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//! non-root, because `mach_host_self()` doesn’t return the privileged
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//! `host_priv` port to non-root users, and this is the target port
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//! that’s required for `host_get_exception_ports()` and
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//! `host_set_exception_ports()`.
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kTargetTypeHost = 0,
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//! \brief A task exception target.
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//!
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//! `task_get_exception_ports()` and `task_set_exception_ports()` will be
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//! used. If no target port is explicitly provided, `mach_task_self()` will
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//! be used as the target port.
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kTargetTypeTask,
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//! \brief A thread exception target.
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//!
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//! `thread_get_exception_ports()` and `thread_set_exception_ports()` will
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//! be used. If no target port is explicitly provided, `mach_thread_self()`
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//! will be used as the target port.
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kTargetTypeThread,
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};
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//! \brief Information about a registered exception handler.
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struct ExceptionHandler {
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//! \brief A mask specifying the exception types to direct to \a port,
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//! containing `EXC_MASK_*` values.
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exception_mask_t mask;
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//! \brief A send right to a Mach port that will handle exceptions of the
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//! types indicated in \a mask.
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exception_handler_t port;
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//! \brief The “behavior” that the exception handler at \a port implements:
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//! `EXCEPTION_DEFAULT`, `EXCEPTION_STATE`, or
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//! `EXCEPTION_STATE_IDENTITY`, possibly combined with
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//! `MACH_EXCEPTION_CODES`.
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exception_behavior_t behavior;
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//! \brief The thread state flavor that the exception handler at \a port
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//! will receive and possibly modify. This member has no effect for \a
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//! \a behavior values that indicate a “default” behavior.
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thread_state_flavor_t flavor;
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};
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//! \brief Wraps `std::vector<ExceptionHandler>`, providing proper cleanup of
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//! the send rights contained in each element’s ExceptionHandler::port.
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//!
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//! Upon destruction or clear(), an object of this class will deallocate all
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//! send rights it contains. Otherwise, it is an interface-compatible drop-in
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//! replacement for `std::vector<ExceptionHandler>`. Note that non-`const`
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//! mutators are not provided to avoid accidental Mach right leaks.
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class ExceptionHandlerVector {
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public:
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using VectorType = std::vector<ExceptionHandler>;
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ExceptionHandlerVector();
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~ExceptionHandlerVector();
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VectorType::const_iterator begin() const { return vector_.begin(); }
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VectorType::const_iterator end() const { return vector_.end(); }
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VectorType::size_type size() const { return vector_.size(); }
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bool empty() const { return vector_.empty(); }
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VectorType::const_reference operator[](VectorType::size_type index) const {
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return vector_[index];
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}
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void push_back(VectorType::value_type& value) { vector_.push_back(value); }
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void clear();
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private:
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void Deallocate();
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VectorType vector_;
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DISALLOW_COPY_AND_ASSIGN(ExceptionHandlerVector);
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};
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//! \brief Constructs an interface object to get or set exception ports on a
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//! host, task, or thread port.
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//!
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//! \param[in] target_type The type of target on which the exception ports are
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//! to be get or set: #kTargetTypeHost, #kTargetTypeTask, or or
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//! #kTargetTypeThread. The correct functions for
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//! `*_get_exception_ports()` and `*_set_exception_ports()` will be used.
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//! \param[in] target_port The target on which to call
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//! `*_get_exception_ports()` or `*_set_exception_ports()`. The target
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//! port must be a send right to a port of the type specified in \a
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//! target_type. In this case, ownership of \a target_port is not given to
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//! the new ExceptionPorts object. \a target_port may also be
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//! `HOST_NULL`, `TASK_NULL`, or `THREAD_NULL`, in which case
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//! `mach_host_self()`, `mach_task_self()`, or `mach_thread_self()` will
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//! be used as the target port depending on the value of \a target_type.
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//! In this case, ownership of the target port will be managed
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//! appropriately for \a target_type.
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ExceptionPorts(TargetType target_type, mach_port_t target_port);
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~ExceptionPorts();
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//! \brief Calls `*_get_exception_ports()` on the target.
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//!
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//! \param[in] mask The exception mask, containing the `EXC_MASK_*` values to
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//! be looked up and returned in \a handlers.
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//! \param[out] handlers The exception handlers registered for \a target_port
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//! to handle exceptions indicated in \a mask. If no execption port is
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//! registered for a bit in \a mask, \a handlers will not contain an entry
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//! corresponding to that bit. This is a departure from the
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//! `*_get_exception_ports()` functions, which may return a handler whose
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//! port is set to `EXCEPTION_PORT_NULL` in this case. On failure, this
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//! argument is untouched.
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//!
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//! \return `true` if `*_get_exception_ports()` returned `KERN_SUCCESS`, with
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//! \a handlers set appropriately. `false` otherwise, with an appropriate
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//! message logged.
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bool GetExceptionPorts(exception_mask_t mask,
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ExceptionHandlerVector* handlers) const;
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//! \brief Calls `*_set_exception_ports()` on the target.
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//!
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//! \param[in] mask A mask specifying the exception types to direct to \a
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//! port, containing `EXC_MASK_*` values.
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//! \param[in] port A send right to a Mach port that will handle exceptions
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//! sustained by \a target_port of the types indicated in \a mask. The
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//! send right is copied, not consumed, by this call.
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//! \param[in] behavior The “behavior” that the exception handler at \a port
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//! implements: `EXCEPTION_DEFAULT`, `EXCEPTION_STATE`, or
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//! `EXCEPTION_STATE_IDENTITY`, possibly combined with
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//! `MACH_EXCEPTION_CODES`.
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//! \param[in] flavor The thread state flavor that the exception handler at \a
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//! port expects to receive and possibly modify. This argument has no
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//! effect for \a behavior values that indicate a “default” behavior.
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//!
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//! \return `true` if `*_set_exception_ports()` returned `KERN_SUCCESS`.
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//! `false` otherwise, with an appropriate message logged.
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bool SetExceptionPort(exception_mask_t mask,
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exception_handler_t port,
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exception_behavior_t behavior,
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thread_state_flavor_t flavor) const;
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//! \brief Calls `*_swap_exception_ports()` on the target.
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//!
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//! \param[in] mask A mask specifying the exception types to direct to \a
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//! port, containing `EXC_MASK_*` values.
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//! \param[in] new_port A send right to a Mach port that will handle
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//! exceptions sustained by \a target_port of the types indicated in \a
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//! mask. The send right is copied, not consumed, by this call.
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//! \param[in] new_behavior The “behavior” that the exception handler at \a
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//! port implements: `EXCEPTION_DEFAULT`, `EXCEPTION_STATE`, or
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//! `EXCEPTION_STATE_IDENTITY`, possibly combined with
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//! `MACH_EXCEPTION_CODES`.
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//! \param[in] new_flavor The thread state flavor that the exception handler
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//! at \a port expects to receive and possibly modify. This argument has
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//! no effect for \a new_behavior values that indicate a “default”
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//! behavior.
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//! \param[out] old_handlers The exception handlers registered for \a
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//! target_port to handle exceptions indicated in \a mask. If no execption
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//! port is registered for a bit in \a mask, \a old_handlers will not
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//! contain an entry corresponding to that bit. This is a departure from
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//! the `*_get_exception_ports()` functions, which may return a handler
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//! whose port is set to `EXCEPTION_PORT_NULL` in this case. On failure,
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//! this argument is untouched.
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//!
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//! \return `true` if `*_swap_exception_ports()` returned `KERN_SUCCESS`, with
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//! \a old_handlers set appropriately. . `false` otherwise, with an
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//! appropriate message logged.
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bool SwapExceptionPorts(exception_mask_t mask,
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exception_handler_t new_port,
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exception_behavior_t new_behavior,
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thread_state_flavor_t new_flavor,
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ExceptionHandlerVector* old_handlers) const;
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//! \brief Returns a string identifying the target type.
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//!
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//! \return `"host"`, `"task"`, or `"thread"`, as appropriate.
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const char* TargetTypeName() const;
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private:
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using GetExceptionPortsType = kern_return_t(*)(mach_port_t,
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exception_mask_t,
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exception_mask_array_t,
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mach_msg_type_number_t*,
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exception_handler_array_t,
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exception_behavior_array_t,
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exception_flavor_array_t);
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using SetExceptionPortsType = kern_return_t(*)(mach_port_t,
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exception_mask_t,
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exception_handler_t,
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exception_behavior_t,
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thread_state_flavor_t);
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using SwapExceptionPortsType = kern_return_t(*)(mach_port_t,
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exception_mask_t,
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exception_handler_t,
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exception_behavior_t,
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thread_state_flavor_t,
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exception_mask_array_t,
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mach_msg_type_number_t*,
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exception_handler_array_t,
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exception_behavior_array_t,
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exception_flavor_array_t);
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GetExceptionPortsType get_exception_ports_;
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SetExceptionPortsType set_exception_ports_;
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SwapExceptionPortsType swap_exception_ports_;
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const char* target_name_;
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mach_port_t target_port_;
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// If true, target_port_ will be deallocated in the destructor. This will
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// always be false when the user provides a non-null target_port to the
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// constructor. It will also be false when target_type is kTargetTypeTask,
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// even with a TASK_NULL target_port, because it is incorrect to deallocate
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// the result of mach_task_self().
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bool dealloc_target_port_;
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DISALLOW_COPY_AND_ASSIGN(ExceptionPorts);
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};
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} // namespace crashpad
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#endif // CRASHPAD_UTIL_MACH_EXCEPTION_PORTS_H_
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