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105 lines
3.0 KiB
C++
105 lines
3.0 KiB
C++
// mmap_posix.cpp
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/* Copyright 2009 10gen Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "stdafx.h"
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#include "mmap.h"
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#include "file_allocator.h"
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#include <errno.h>
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#include <sys/mman.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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namespace mongo {
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MemoryMappedFile::MemoryMappedFile() {
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fd = 0;
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maphandle = 0;
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view = 0;
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len = 0;
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created();
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}
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void MemoryMappedFile::close() {
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if ( view )
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munmap(view, len);
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view = 0;
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if ( fd )
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::close(fd);
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fd = 0;
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}
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#ifndef O_NOATIME
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#define O_NOATIME 0
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#endif
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void* MemoryMappedFile::map(const char *filename, long &length, int options) {
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// length may be updated by callee.
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theFileAllocator().allocateAsap( filename, length );
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len = length;
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massert( 10446 , (string)"mmap() can't map area of size 0 [" + filename + "]" , length > 0 );
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fd = open(filename, O_RDWR | O_NOATIME);
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if ( fd <= 0 ) {
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out() << "couldn't open " << filename << ' ' << OUTPUT_ERRNO << endl;
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return 0;
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}
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off_t filelen = lseek(fd, 0, SEEK_END);
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if ( filelen != length ){
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cout << "wanted length: " << length << " filelen: " << filelen << endl;
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cout << sizeof(size_t) << endl;
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massert( 10447 , "file size allocation failed", filelen == length );
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}
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lseek( fd, 0, SEEK_SET );
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view = mmap(NULL, length, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
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if ( view == MAP_FAILED ) {
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out() << " mmap() failed for " << filename << " len:" << length << " " << OUTPUT_ERRNO << endl;
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if ( errno == ENOMEM ){
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out() << " mmap failed with out of memory, if you're using 32-bits, then you probably need to upgrade to 64" << endl;
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}
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return 0;
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}
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#if defined(__sunos__)
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#warning madvise not supported on solaris yet
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#else
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if ( options & SEQUENTIAL ){
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if ( madvise( view , length , MADV_SEQUENTIAL ) ){
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out() << " madvise failed for " << filename << " " << OUTPUT_ERRNO << endl;
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}
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}
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#endif
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return view;
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}
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void MemoryMappedFile::flush(bool sync) {
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if ( view == 0 || fd == 0 )
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return;
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if ( msync(view, len, sync ? MS_SYNC : MS_ASYNC) )
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problem() << "msync " << OUTPUT_ERRNO << endl;
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}
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} // namespace mongo
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