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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.
*/
#include "base/logging.h"
#include "base/unix_file/mapped_file.h"
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <string>
namespace unix_file {
MappedFile::~MappedFile() {
}
int MappedFile::Close() {
if (IsMapped()) {
Unmap();
}
return FdFile::Close();
}
bool MappedFile::MapReadOnly() {
CHECK(IsOpened());
CHECK(!IsMapped());
struct stat st;
int result = TEMP_FAILURE_RETRY(fstat(Fd(), &st));
if (result == -1) {
PLOG(WARNING) << "Failed to stat file '" << GetPath() << "'";
return false;
}
file_size_ = st.st_size;
do {
mapped_file_ = mmap(NULL, file_size_, PROT_READ, MAP_PRIVATE, Fd(), 0);
} while (mapped_file_ == MAP_FAILED && errno == EINTR);
if (mapped_file_ == MAP_FAILED) {
PLOG(WARNING) << "Failed to mmap file '" << GetPath() << "' of size "
<< file_size_ << " bytes to memory";
return false;
}
map_mode_ = kMapReadOnly;
return true;
}
bool MappedFile::MapReadWrite(int64_t file_size) {
CHECK(IsOpened());
CHECK(!IsMapped());
#ifdef __linux__
int result = TEMP_FAILURE_RETRY(ftruncate64(Fd(), file_size));
#else
int result = TEMP_FAILURE_RETRY(ftruncate(Fd(), file_size));
#endif
if (result == -1) {
PLOG(ERROR) << "Failed to truncate file '" << GetPath()
<< "' to size " << file_size;
return false;
}
file_size_ = file_size;
do {
mapped_file_ =
mmap(NULL, file_size_, PROT_READ | PROT_WRITE, MAP_SHARED, Fd(), 0);
} while (mapped_file_ == MAP_FAILED && errno == EINTR);
if (mapped_file_ == MAP_FAILED) {
PLOG(WARNING) << "Failed to mmap file '" << GetPath() << "' of size "
<< file_size_ << " bytes to memory";
return false;
}
map_mode_ = kMapReadWrite;
return true;
}
bool MappedFile::Unmap() {
CHECK(IsMapped());
int result = TEMP_FAILURE_RETRY(munmap(mapped_file_, file_size_));
if (result == -1) {
PLOG(WARNING) << "Failed unmap file '" << GetPath() << "' of size "
<< file_size_;
return false;
} else {
mapped_file_ = NULL;
file_size_ = -1;
return true;
}
}
int64_t MappedFile::Read(char* buf, int64_t byte_count, int64_t offset) const {
if (IsMapped()) {
if (offset < 0) {
errno = EINVAL;
return -errno;
}
int64_t read_size = std::max(static_cast<int64_t>(0),
std::min(byte_count, file_size_ - offset));
if (read_size > 0) {
memcpy(buf, data() + offset, read_size);
}
return read_size;
} else {
return FdFile::Read(buf, byte_count, offset);
}
}
int MappedFile::SetLength(int64_t new_length) {
CHECK(!IsMapped());
return FdFile::SetLength(new_length);
}
int64_t MappedFile::GetLength() const {
if (IsMapped()) {
return file_size_;
} else {
return FdFile::GetLength();
}
}
int MappedFile::Flush() {
int rc = IsMapped() ? TEMP_FAILURE_RETRY(msync(mapped_file_, file_size_, 0)) : FdFile::Flush();
return rc == -1 ? -errno : 0;
}
int64_t MappedFile::Write(const char* buf, int64_t byte_count, int64_t offset) {
if (IsMapped()) {
CHECK_EQ(kMapReadWrite, map_mode_);
if (offset < 0) {
errno = EINVAL;
return -errno;
}
int64_t write_size = std::max(static_cast<int64_t>(0),
std::min(byte_count, file_size_ - offset));
if (write_size > 0) {
memcpy(data() + offset, buf, write_size);
}
return write_size;
} else {
return FdFile::Write(buf, byte_count, offset);
}
}
int64_t MappedFile::size() const {
return GetLength();
}
bool MappedFile::IsMapped() const {
return mapped_file_ != NULL && mapped_file_ != MAP_FAILED;
}
char* MappedFile::data() const {
CHECK(IsMapped());
return static_cast<char*>(mapped_file_);
}
} // namespace unix_file
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