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This wraps mmap(), munmap(), and mprotect(). Bug: crashpad:30 Test: crashpad_util_test ScopedMmap.* Change-Id: If14363dfd00e314482cc91e53c7f4e3df737b0d3 Reviewed-on: https://chromium-review.googlesource.com/461361 Reviewed-by: Joshua Peraza <jperaza@chromium.org>
101 lines
3.3 KiB
C++
101 lines
3.3 KiB
C++
// Copyright 2017 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_POSIX_SCOPED_MMAP_H_
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#define CRASHPAD_UTIL_POSIX_SCOPED_MMAP_H_
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#include "base/macros.h"
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#include <sys/mman.h>
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#include <sys/types.h>
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namespace crashpad {
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//! \brief Maintains a memory-mapped region created by `mmap()`.
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//!
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//! On destruction, any memory-mapped region managed by an object of this class
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//! will be released by calling `munmap()`.
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class ScopedMmap {
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public:
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ScopedMmap();
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~ScopedMmap();
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//! \brief Releases the memory-mapped region by calling `munmap()`.
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//!
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//! A message will be logged on failure.
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void Reset();
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//! \brief Releases any existing memory-mapped region and sets the object to
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//! maintain an already-established mapping.
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//!
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//! \param[in] addr The base address of the existing memory-mapped region to
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//! maintain.
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//! \param[in] len The size of the existing memory-mapped region to maintain.
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//!
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//! A message will be logged on failure to release any existing memory-mapped
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//! region, but the new mapping will be set regardless.
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void ResetAddrLen(void* addr, size_t len);
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//! \brief Releases any existing memory-mapped region and establishes a new
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//! one by calling `mmap()`.
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//!
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//! The parameters to this method are passed directly to `mmap()`.
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//!
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//! \return `true` on success. `false` on failure, with a message logged. A
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//! message will also be logged on failure to release any existing
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//! memory-mapped region, but this will not preclude `mmap()` from being
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//! called or a new mapping from being established, and if such a call to
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//! `mmap()` is successful, this method will return `true`.
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bool ResetMmap(void* addr,
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size_t len,
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int prot,
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int flags,
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int fd,
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off_t offset);
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//! \brief Sets the protection of the memory-mapped region by calling
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//! `mprotect()`.
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//!
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//! \a prot is passed directly to `mprotect()`.
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//!
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//! \return `true` on success. `false` on failure, with a message logged.
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bool Mprotect(int prot);
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//! \return Whether this object is managing a valid memory-mapped region.
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bool is_valid() const { return addr_ != MAP_FAILED; }
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//! \brief Returns the base address of the memory-mapped region.
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void* addr() const { return addr_; }
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//! \brief Returns the base address of the memory-mapped region, casted to
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//! a type of the caller’s choosing.
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template <typename T>
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T addr_as() const {
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return reinterpret_cast<T>(addr_);
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}
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//! \brief Returns the size of the memory-mapped region.
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size_t len() const { return len_; }
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private:
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void* addr_ = MAP_FAILED;
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size_t len_ = 0;
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DISALLOW_COPY_AND_ASSIGN(ScopedMmap);
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};
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} // namespace crashpad
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#endif // CRASHPAD_UTIL_POSIX_SCOPED_MMAP_H_
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