mac: Don’t leak send rights from ExceptionPorts::GetExceptionPorts()

util/mach/exception_ports.h

 // 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,
@@ skipping 67 matching lines @@
     //!     `EXCEPTION_STATE_IDENTITY`, possibly combined with
     //!     `MACH_EXCEPTION_CODES`.
     exception_behavior_t behavior;
 
     //! \brief The thread state flavor that the exception handler at \a port
     //!     will receive and possibly modify. This member has no effect for \a
     //!     \a behavior values that indicate a “default” behavior.
     thread_state_flavor_t flavor;
   };
 
+  //! \brief Wraps `std::vector<ExceptionHandler>`, providing proper cleanup of
+  //!     the send rights contained in each element’s ExceptionHandler::port.
+  //!
+  //! Upon destruction or clear(), an object of this class will deallocate all
+  //! send rights it contains. Otherwise, it is an interface-compatible drop-in
+  //! replacement for `std::vector<ExceptionHandler>`. Note that non-`const`
+  //! mutators are not provided to avoid accidental Mach right leaks.
+  class ExceptionHandlerVector {
+   public:
+    using VectorType = std::vector<ExceptionHandler>;
+
+    ExceptionHandlerVector();
+    ~ExceptionHandlerVector();
+
+    VectorType::const_iterator begin() const { return vector_.begin(); }
+    VectorType::const_iterator end() const { return vector_.end(); }
+    VectorType::size_type size() const { return vector_.size(); }
+    bool empty() const { return vector_.empty(); }
+    VectorType::const_reference operator[](VectorType::size_type index) const {
+      return vector_[index];
+    }
+    void push_back(VectorType::value_type& value) { vector_.push_back(value); }
+    void clear();
+
+   private:
+    void Deallocate();
+
+    VectorType vector_;
+
+    DISALLOW_COPY_AND_ASSIGN(ExceptionHandlerVector);
+  };
+
   //! \brief Constructs an interface object to get or set exception ports on a
   //!     host, task, or thread port.
   //!
   //! \param[in] target_type The type of target on which the exception ports are
   //!     to be get or set: #kTargetTypeHost, #kTargetTypeTask, or or
   //!     #kTargetTypeThread. The correct functions for
   //!     `*_get_exception_ports()` and `*_set_exception_ports()` will be used.
   //! \param[in] target_port The target on which to call
   //!     `*_get_exception_ports()` or `*_set_exception_ports()`. The target
   //!     port must be a send right to a port of the type specified in \a
   //!     target_type. In this case, ownership of \a target_port is not given to
   //!     the new ExceptionPorts object. \a target_port may also be
   //!     `HOST_NULL`, `TASK_NULL`, or `THREAD_NULL`, in which case
   //!     `mach_host_self()`, `mach_task_self()`, or `mach_thread_self()` will
   //!     be used as the target port depending on the value of \a target_type.
   //!     In this case, ownership of the target port will be managed
   //!     appropriately for \a target_type.
   ExceptionPorts(TargetType target_type, mach_port_t target_port);
 
   ~ExceptionPorts();
 
   //! \brief Calls `*_get_exception_ports()` on the target.
   //!
   //! \param[in] mask The exception mask, containing the `EXC_MASK_*` values to
   //!     be looked up and returned in \a handlers.
   //! \param[out] handlers The exception handlers registered for \a target_port
-  //!     to handle exceptions indicated in \a mask. The caller must take
-  //!     ownership of the \a port members of the returned ExceptionHandler
-  //!     objects. If no execption port is registered for a bit in \a mask, \a
-  //!     handlers will not contain an entry corresponding to that bit. This is
-  //!     a departure from the `*_get_exception_ports()` functions, which may
-  //!     return a handler whose port is set to `EXCEPTION_PORT_NULL` in this
-  //!     case. On failure, this argument is untouched.
+  //!     to handle exceptions indicated in \a mask. If no execption port is
+  //!     registered for a bit in \a mask, \a handlers will not contain an entry
+  //!     corresponding to that bit. This is a departure from the
+  //!     `*_get_exception_ports()` functions, which may return a handler whose
+  //!     port is set to `EXCEPTION_PORT_NULL` in this case. On failure, this
+  //!     argument is untouched.
   //!
   //! \return `true` if `*_get_exception_ports()` returned `KERN_SUCCESS`, with
   //!     \a handlers set appropriately. `false` otherwise, with an appropriate
   //!     message logged.
   bool GetExceptionPorts(exception_mask_t mask,
-                         std::vector<ExceptionHandler>* handlers) const;
+                         ExceptionHandlerVector* handlers) const;
 
   //! \brief Calls `*_set_exception_ports()` on the target.
   //!
   //! \param[in] mask A mask specifying the exception types to direct to \a
   //!     port, containing `EXC_MASK_*` values.
   //! \param[in] port A send right to a Mach port that will handle exceptions
   //!     sustained by \a target_port of the types indicated in \a mask. The
   //!     send right is copied, not consumed, by this call.
   //! \param[in] behavior The “behavior” that the exception handler at \a port
   //!     implements: `EXCEPTION_DEFAULT`, `EXCEPTION_STATE`, or
@@ skipping 41 matching lines @@
   // even with a TASK_NULL target_port, because it is incorrect to deallocate
   // the result of mach_task_self().
   bool dealloc_target_port_;
 
   DISALLOW_COPY_AND_ASSIGN(ExceptionPorts);
 };
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_MACH_EXCEPTION_PORTS_H_