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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_RUNTIME_MEM_MAP_H_
#define ART_RUNTIME_MEM_MAP_H_
#include <string>
#include <stddef.h>
#include <sys/mman.h> // For the PROT_* and MAP_* constants.
#include <sys/types.h>
#include "globals.h"
namespace art {
// Used to keep track of mmap segments.
class MemMap {
public:
// Request an anonymous region of length 'byte_count' and a requested base address.
// Use NULL as the requested base address if you don't care.
//
// The word "anonymous" in this context means "not backed by a file". The supplied
// 'ashmem_name' will be used -- on systems that support it -- to give the mapping
// a name.
//
// On success, returns returns a MemMap instance. On failure, returns a NULL;
static MemMap* MapAnonymous(const char* ashmem_name, byte* addr, size_t byte_count, int prot);
// Map part of a file, taking care of non-page aligned offsets. The
// "start" offset is absolute, not relative.
//
// On success, returns returns a MemMap instance. On failure, returns a NULL;
static MemMap* MapFile(size_t byte_count, int prot, int flags, int fd, off_t start) {
return MapFileAtAddress(NULL, byte_count, prot, flags, fd, start, false);
}
// Map part of a file, taking care of non-page aligned offsets. The
// "start" offset is absolute, not relative. This version allows
// requesting a specific address for the base of the mapping.
//
// On success, returns returns a MemMap instance. On failure, returns a NULL;
static MemMap* MapFileAtAddress(
byte* addr, size_t byte_count, int prot, int flags, int fd, off_t start, bool reuse);
// Releases the memory mapping
~MemMap();
bool Protect(int prot);
int GetProtect() const {
return prot_;
}
byte* Begin() const {
return begin_;
}
size_t Size() const {
return size_;
}
byte* End() const {
return Begin() + Size();
}
bool HasAddress(const void* addr) const {
return Begin() <= addr && addr < End();
}
// Trim by unmapping pages at the end of the map.
void UnMapAtEnd(byte* new_end);
private:
MemMap(const std::string& name, byte* begin, size_t size, void* base_begin, size_t base_size,
int prot);
std::string name_;
byte* const begin_; // Start of data.
size_t size_; // Length of data.
void* const base_begin_; // Page-aligned base address.
const size_t base_size_; // Length of mapping.
int prot_; // Protection of the map.
};
} // namespace art
#endif // ART_RUNTIME_MEM_MAP_H_
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