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This CL introduces a new class ScopedVMMap, a fork of ScopedVMRead which maps the memory using vm_remap() instead of reading it. This is useful for Annotations which use ScopedSpinGuard to protect reads from simultaneous writes; the in-process intermediate dump handler can try to take the spin guard when reading such an Annotation and skip reading it if it the spin guard could not be obtained. Change-Id: I60d7a48d1ba4e5d2dfdb44307b78b4d9ffb73560 Bug: crashpad:437 Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/4114550 Reviewed-by: Mark Mentovai <mark@chromium.org> Commit-Queue: Ben Hamilton <benhamilton@google.com>
126 lines
4.1 KiB
C++
126 lines
4.1 KiB
C++
// Copyright 2023 The Crashpad Authors
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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_IOS_SCOPED_VM_MAP_H_
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#define CRASHPAD_UTIL_IOS_SCOPED_VM_MAP_H_
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#include <mach/mach.h>
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namespace crashpad {
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namespace internal {
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//! \brief Non-templated internal class to be used by ScopedVMMap.
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//!
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//! Note: RUNS-DURING-CRASH.
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class ScopedVMMapInternal {
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public:
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ScopedVMMapInternal();
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ScopedVMMapInternal(const ScopedVMMapInternal&) = delete;
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ScopedVMMapInternal& operator=(const ScopedVMMapInternal&) = delete;
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~ScopedVMMapInternal();
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//! \brief Releases any previously mapped data and vm_remaps \a data. Logs an
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//! error on failure.
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//!
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//! \param[in] data Memory to be mapped by vm_remap.
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//! \param[in] data_length Length of \a data.
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//!
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//! \return `true` if all the data was mapped. Logs an error and returns false
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//! on failure.
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bool Map(const void* data, size_t data_length);
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//! \brief Returns the current protection for the memory in the region.
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vm_prot_t CurrentProtection() const { return cur_protection_; }
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vm_address_t data() const { return data_; }
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private:
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//! \brief Deallocates any resources allocated by this object and resets it
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//! to its original state.
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void Reset();
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// The address within region_start_ at which the mapped data is available.
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vm_address_t data_;
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// The region returned by vm_remap().
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vm_address_t region_start_;
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// The size of the region returned by vm_remap().
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vm_size_t region_size_;
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// The current protection for the memory region.
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vm_prot_t cur_protection_;
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};
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//! \brief A scoped wrapper for calls to `vm_remap` and `vm_deallocate`. Allows
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//! in-process handler to safely read and write memory (modulo its
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//! protection level) for the intermediate dump.
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//!
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//! Note: RUNS-DURING-CRASH.
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template <typename T>
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class ScopedVMMap {
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public:
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ScopedVMMap() : internal_() {}
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ScopedVMMap(const ScopedVMMap&) = delete;
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ScopedVMMap& operator=(const ScopedVMMap&) = delete;
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~ScopedVMMap() {}
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//! \brief Releases any previously mapped data and vm_remaps data.
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//!
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//! \param[in] data Memory to be mapped by vm_remap.
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//! \param[in] count Length of \a data.
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//!
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//! \return `true` if all \a data was mapped. Returns false on failure.
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bool Map(const void* data, size_t count = 1) {
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size_t data_length = count * sizeof(T);
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return internal_.Map(data, data_length);
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}
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//! \brief Releases any previously mapped data and vm_remaps address.
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//!
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//! Before reading or writing the memory, check `CurrentProtection()` to
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//! ensure the data is readable or writable.
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//!
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//! \param[in] address Address of memory to be mapped by vm_remap.
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//! \param[in] count Length of \a data.
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//!
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//! \return `true` if all of \a address was mapped. Returns false on failure.
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bool Map(vm_address_t address, size_t count = 1) {
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return Map(reinterpret_cast<T*>(address), count);
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}
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//! \brief Returns the pointer to memory safe to read and write (respecting
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//! the CurrentProtection() level) during the in-process crash handler.
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T* operator->() const { return get(); }
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//! \brief Returns the pointer to memory safe to read and write (respecting
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//! the CurrentProtection() level) during the in-process crash handler.
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T* get() const { return reinterpret_cast<T*>(internal_.data()); }
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//! \brief Returns the current protection level of the mapped memory.
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vm_prot_t CurrentProtection() const { return internal_.CurrentProtection(); }
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private:
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ScopedVMMapInternal internal_;
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};
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} // namespace internal
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} // namespace crashpad
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#endif // CRASHPAD_UTIL_IOS_SCOPED_VM_MAP_H_
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