145 lines
3.4 KiB
C++
145 lines
3.4 KiB
C++
/* Copyright (C) 1979-1996 TcX AB & Monty Program KB & Detron HB
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This software is distributed with NO WARRANTY OF ANY KIND. No author or
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distributor accepts any responsibility for the consequences of using it, or
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for whether it serves any particular purpose or works at all, unless he or
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she says so in writing. Refer to the Free Public License (the "License")
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for full details.
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Every copy of this file must include a copy of the License, normally in a
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plain ASCII text file named PUBLIC. The License grants you the right to
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copy, modify and redistribute this file, but only under certain conditions
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described in the License. Among other things, the License requires that
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the copyright notice and this notice be preserved on all copies. */
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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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