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/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 "qpid/sys/MemoryMappedFile.h"
#include "qpid/Exception.h"
#include "qpid/Msg.h"
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
namespace qpid {
namespace sys {
namespace {
const std::string PATH_SEPARATOR("/");
const std::string ESCAPE("%");
const std::string VALID("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-.");
std::string getFileName(const std::string& name, const std::string& dir)
{
std::stringstream filename;
if (dir.size()) filename << dir << PATH_SEPARATOR;
size_t start = 0;
while (true) {
size_t i = name.find_first_not_of(VALID, start);
if (i == std::string::npos) {
filename << name.substr(start);
return filename.str();
} else {
if (i > start) filename << name.substr(start, i-start);
filename << ESCAPE << (int) name.at(i);
start = i+1;
}
}
}
}
class MemoryMappedFilePrivate
{
friend class MemoryMappedFile;
int fd;
MemoryMappedFilePrivate() : fd(0) {}
};
MemoryMappedFile::MemoryMappedFile() : state(new MemoryMappedFilePrivate) {}
MemoryMappedFile::~MemoryMappedFile() { delete state; }
std::string MemoryMappedFile::open(const std::string& name, const std::string& directory)
{
std::string path = getFileName(name, directory);
if (access(path.c_str(), F_OK) != -1) throw qpid::Exception(QPID_MSG("Attempting to re-write file " << path << " for paged queue \"" << name << "\""));
int flags = O_CREAT | O_TRUNC | O_RDWR;
int fd = ::open(path.c_str(), flags, S_IRUSR | S_IWUSR);
if (fd == -1) throw qpid::Exception(QPID_MSG("Failed to open memory mapped file " << path << ": " << qpid::sys::strError(errno) << " [flags=" << flags << "]"));
state->fd = fd;
return path;
}
void MemoryMappedFile::close(const std::string& path)
{
::close(state->fd);
::unlink(path.c_str());
}
size_t MemoryMappedFile::getPageSize()
{
return ::sysconf(_SC_PAGE_SIZE);
}
char* MemoryMappedFile::map(size_t offset, size_t size)
{
int protection = PROT_READ | PROT_WRITE;
char* region = (char*) ::mmap(0, size, protection, MAP_SHARED, state->fd, offset);
if (region == MAP_FAILED) {
throw qpid::Exception(QPID_MSG("Failed to map page into memory: " << qpid::sys::strError(errno)));
}
return region;
}
void MemoryMappedFile::unmap(char* region, size_t size)
{
::munmap(region, size);
}
void MemoryMappedFile::flush(char* region, size_t size)
{
::msync(region, size, MS_ASYNC);
}
void MemoryMappedFile::expand(size_t offset)
{
if ((::lseek(state->fd, offset - 1, SEEK_SET) == -1) || (::write(state->fd, "", 1) == -1)) {
throw qpid::Exception(QPID_MSG("Failed to expand paged queue file: " << qpid::sys::strError(errno)));
}
}
bool MemoryMappedFile::isSupported()
{
return true;
}
}} // namespace qpid::sys
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