63 lines
1.5 KiB
C++
63 lines
1.5 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "MemoryMappedFile.h"
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// sys/types.h *must* appear before mman.h on some systems.
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// clang-format off
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#include <sys/types.h>
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// clang-format on
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#include <fcntl.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include "private/pprio.h"
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namespace mozilla {
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MemoryMappedFile MemoryMappedFile::OpenRaw(FileHandle aFD, size_t aMaxSize) {
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if (aFD < 0) {
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return {};
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}
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struct stat st;
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// Stat the file, check type, and validate size.
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if (fstat(aFD, &st) != 0 || !S_ISREG(st.st_mode) ||
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st.st_size < 0 || // off_t is signed.
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static_cast<uint64_t>(st.st_size) > static_cast<uint64_t>(aMaxSize)) {
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return {};
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}
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const size_t size = st.st_size;
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// Zero-size needs special handling.
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if (size == 0) {
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return Empty();
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}
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const void* data = mmap(nullptr, size, PROT_READ, MAP_PRIVATE, aFD, 0);
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// mmap returns MAP_FAILED (usually -1) on failure, not NULL.
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if (data != MAP_FAILED) {
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return MemoryMappedFile(data, size);
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}
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return {};
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}
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MemoryMappedFile MemoryMappedFile::Open(PRFileDesc* aPRFile, size_t aMaxSize) {
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if (!aPRFile) {
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return {};
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}
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const int fd = PR_FileDesc2NativeHandle(aPRFile);
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return OpenRaw(fd, aMaxSize);
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}
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void MemoryMappedFile::Unmap() {
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if (mSize) {
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munmap((void*)mData, mSize);
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}
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mSize = 0;
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mData = nullptr;
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}
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} // namespace mozilla
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