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