mirror of
https://github.com/MariaDB/server.git
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147 lines
3.4 KiB
C++
147 lines
3.4 KiB
C++
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#ifdef __GNUC__
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#pragma implementation // gcc: Class implementation
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#endif
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#include "mysql_priv.h"
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#ifdef HAVE_MMAP
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#include <sys/mman.h>
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#include <sys/stat.h>
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#endif
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#ifndef MAP_NORESERVE
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#define MAP_NORESERVE 0 // For IRIX
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#endif
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mapped_files::mapped_files(const my_string filename,byte *magic,uint magic_length)
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{
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#ifdef HAVE_MMAP
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name=my_strdup(filename,MYF(0));
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use_count=1;
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error=0;
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map=0;
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size=0;
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if ((file=my_open(name,O_RDONLY,MYF(MY_WME))) >= 0)
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{
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struct stat stat_buf;
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if (!fstat(file,&stat_buf))
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{
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if (!(map=(byte*) mmap(0,(size=(ulong) stat_buf.st_size),PROT_READ,
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MAP_SHARED | MAP_NORESERVE,file,
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0L)))
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{
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error=errno;
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my_printf_error(0,"Can't map file: %s, errno: %d",MYF(0),
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(my_string) name,error);
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}
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}
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if (map && memcmp(map,magic,magic_length))
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{
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my_printf_error(0,"Wrong magic in %s",MYF(0),name);
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VOID(munmap(map,size));
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map=0;
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}
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if (!map)
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{
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VOID(my_close(file,MYF(0)));
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file= -1;
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}
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}
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#endif
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}
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mapped_files::~mapped_files()
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{
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#ifdef HAVE_MMAP
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if (file >= 0)
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{
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VOID(munmap((caddr_t) map,size));
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VOID(my_close(file,MYF(0)));
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file= -1; map=0;
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}
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my_free(name,MYF(0));
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#endif
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}
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static I_List<mapped_files> maps_in_use;
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/*
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** Check if a file is mapped. If it is, then return pointer to old map,
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** else alloc new object
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*/
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mapped_files *map_file(const my_string name,byte *magic,uint magic_length)
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{
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#ifdef HAVE_MMAP
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VOID(pthread_mutex_lock(&LOCK_mapped_file));
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I_List_iterator<mapped_files> list(maps_in_use);
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mapped_files *map;
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char path[FN_REFLEN];
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sprintf(path,"%s/%s/%s.uniq",mysql_data_home,current_thd->db,name);
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(void) unpack_filename(path,path);
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while ((map=list++))
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{
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if (!strcmp(path,map->name))
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break;
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}
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if (!map)
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{
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map=new mapped_files(path,magic,magic_length);
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maps_in_use.append(map);
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}
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else
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{
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map->use_count++;
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if (!map->map)
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my_printf_error(0,"Can't map file: %s, error: %d",MYF(0),path,
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map->error);
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}
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VOID(pthread_mutex_unlock(&LOCK_mapped_file));
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return map;
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#else
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return NULL;
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#endif
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}
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/*
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** free the map if there are no more users for it
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*/
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void unmap_file(mapped_files *map)
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{
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#ifdef HAVE_MMAP
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VOID(pthread_mutex_lock(&LOCK_mapped_file));
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if (!map->use_count--)
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delete map;
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VOID(pthread_mutex_unlock(&LOCK_mapped_file));
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#endif
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}
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/*****************************************************************************
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** Instansiate templates
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*****************************************************************************/
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#ifdef __GNUC__
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/* Used templates */
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template class I_List<mapped_files>;
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template class I_List_iterator<mapped_files>;
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#endif
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