71 lines
2.2 KiB
C++
71 lines
2.2 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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#include "util/misc/reinterpret_bytes.h"
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#include <string.h>
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#include <algorithm>
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#include "base/logging.h"
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namespace crashpad {
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namespace internal {
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bool ReinterpretBytesImpl(const char* data,
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size_t data_size,
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char* dest,
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size_t dest_size) {
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// Verify that any unused bytes from data are zero.
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// The unused bytes are at the start of the data buffer for big-endian and the
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// end of the buffer for little-endian.
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if (dest_size < data_size) {
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auto extra_bytes = data;
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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extra_bytes += dest_size;
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#endif // ARCH_CPU_LITTLE_ENDIAN
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uint64_t zero = 0;
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size_t extra_bytes_size = data_size - dest_size;
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while (extra_bytes_size > 0) {
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size_t to_check = std::min(extra_bytes_size, sizeof(zero));
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if (memcmp(extra_bytes, &zero, to_check) != 0) {
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LOG(ERROR) << "information loss";
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return false;
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}
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extra_bytes += to_check;
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extra_bytes_size -= to_check;
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}
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}
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// Zero out the destination, in case it is larger than data.
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memset(dest, 0, dest_size);
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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// Copy a prefix of data to a prefix of dest for little-endian
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memcpy(dest, data, std::min(dest_size, data_size));
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#else
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// or the suffix of data to the suffix of dest for big-endian
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if (data_size >= dest_size) {
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memcpy(dest, data + data_size - dest_size, dest_size);
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} else {
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memcpy(dest + dest_size - data_size, data, data_size);
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}
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#endif // ARCH_CPU_LITTLE_ENDIAN
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return true;
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}
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} // namespace internal
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} // namespace crashpad
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