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// mmap_posix.cpp
/* Copyright 2009 10gen Inc.
*
* 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 "pch.h"
#include "mmap.h"
#include "file_allocator.h"
#include "../db/concurrency.h"
#include <errno.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
namespace mongo {
MemoryMappedFile::MemoryMappedFile() {
fd = 0;
maphandle = 0;
len = 0;
created();
}
void MemoryMappedFile::close() {
for( vector<void*>::iterator i = views.begin(); i != views.end(); i++ ) {
munmap(*i,len);
}
if ( fd )
::close(fd);
fd = 0;
}
#ifndef O_NOATIME
#define O_NOATIME (0)
#endif
void* MemoryMappedFile::map(const char *filename, unsigned long long &length, int options) {
// length may be updated by callee.
_filename = filename;
theFileAllocator().allocateAsap( filename, length );
len = length;
massert( 10446 , str::stream() << "mmap: can't map area of size 0 file: " << filename, length > 0 );
fd = open(filename, O_RDWR | O_NOATIME);
if ( fd <= 0 ) {
log() << "couldn't open " << filename << ' ' << errnoWithDescription() << endl;
return 0;
}
unsigned long long filelen = lseek(fd, 0, SEEK_END);
uassert(10447, str::stream() << "map file alloc failed, wanted: " << length << " filelen: " << filelen << ' ' << sizeof(size_t), filelen == length );
lseek( fd, 0, SEEK_SET );
void * view = mmap(NULL, length, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if ( view == MAP_FAILED ) {
error() << " mmap() failed for " << filename << " len:" << length << " " << errnoWithDescription() << endl;
if ( errno == ENOMEM ) {
if( sizeof(void*) == 4 )
error() << "mmap failed with out of memory. You are using a 32-bit build and probably need to upgrade to 64" << endl;
else
error() << "mmap failed with out of memory. (64 bit build)" << endl;
}
return 0;
}
#if defined(__sunos__)
#warning madvise not supported on solaris yet
#else
if ( options & SEQUENTIAL ){
if ( madvise( view , length , MADV_SEQUENTIAL ) ){
warning() << "map: madvise failed for " << filename << ' ' << errnoWithDescription() << endl;
}
}
#endif
DEV if (! dbMutex.info().isLocked()){
_unlock();
}
views.push_back( view );
return view;
}
void* MemoryMappedFile::testGetCopyOnWriteView(){
void * x = mmap( NULL , len , PROT_READ | PROT_WRITE , MAP_PRIVATE , fd , 0 );
assert( x );
return x;
}
void MemoryMappedFile::testCloseCopyOnWriteView(void * x ){
munmap(x,len);
}
void MemoryMappedFile::flush(bool sync) {
if ( views.empty() || fd == 0 )
return;
if ( msync(views[0], len, sync ? MS_SYNC : MS_ASYNC) )
problem() << "msync " << errnoWithDescription() << endl;
}
class PosixFlushable : public MemoryMappedFile::Flushable {
public:
PosixFlushable( void * view , HANDLE fd , long len )
: _view( view ) , _fd( fd ) , _len(len){
}
void flush(){
if ( _view && _fd )
if ( msync(_view, _len, MS_SYNC ) )
problem() << "msync " << errnoWithDescription() << endl;
}
void * _view;
HANDLE _fd;
long _len;
};
MemoryMappedFile::Flushable * MemoryMappedFile::prepareFlush(){
return new PosixFlushable( views.empty() ? 0 : views[0] , fd , len );
}
void MemoryMappedFile::_lock() {
if (! views.empty() ) assert(mprotect(views[0], len, PROT_READ | PROT_WRITE) == 0);
}
void MemoryMappedFile::_unlock() {
if (! views.empty() ) assert(mprotect(views[0], len, PROT_READ) == 0);
}
} // namespace mongo
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