summaryrefslogtreecommitdiff
path: root/sql/sql_map.cc
blob: 78e308dc5511cf1c1f6ba05b92d1dbf13eadc115 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation				// gcc: Class implementation
#endif

#include "mysql_priv.h"
#include <sys/stat.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif

mapped_files::mapped_files(const my_string filename,byte *magic,uint magic_length)
{
#ifdef HAVE_MMAP
  name=my_strdup(filename,MYF(0));
  use_count=1;
  error=0;
  map=0;
  size=0;
  if ((file=my_open(name,O_RDONLY,MYF(MY_WME))) >= 0)
  {
    struct stat stat_buf;
    if (!fstat(file,&stat_buf))
    {
      if (!(map=(byte*) my_mmap(0,(size=(ulong) stat_buf.st_size),PROT_READ,
			     MAP_SHARED | MAP_NORESERVE,file,
			     0L)))
      {
	error=errno;
	my_error(ER_NO_FILE_MAPPING, MYF(0), (my_string) name, error);
      }
    }
    if (map && memcmp(map,magic,magic_length))
    {
      my_error(ER_WRONG_MAGIC, MYF(0), name);
      VOID(my_munmap(map,size));
      map=0;
    }
    if (!map)
    {
      VOID(my_close(file,MYF(0)));
      file= -1;
    }
  }
#endif
}


mapped_files::~mapped_files()
{
#ifdef HAVE_MMAP
  if (file >= 0)
  {
    VOID(my_munmap(map,size));
    VOID(my_close(file,MYF(0)));
    file= -1; map=0;
  }
  my_free(name,MYF(0));
#endif
}


static I_List<mapped_files> maps_in_use;

/*
**  Check if a file is mapped. If it is, then return pointer to old map,
**  else alloc new object
*/

mapped_files *map_file(const my_string name,byte *magic,uint magic_length)
{
#ifdef HAVE_MMAP
  VOID(pthread_mutex_lock(&LOCK_mapped_file));
  I_List_iterator<mapped_files> list(maps_in_use);
  mapped_files *map;
  char path[FN_REFLEN];
  sprintf(path,"%s/%s/%s.uniq",mysql_data_home,current_thd->db,name);
  (void) unpack_filename(path,path);

  while ((map=list++))
  {
    if (!strcmp(path,map->name))
      break;
  }
  if (!map)
  {
    map=new mapped_files(path,magic,magic_length);
    maps_in_use.append(map);
  }
  else
  {
    map->use_count++;
    if (!map->map)
      my_error(ER_NO_FILE_MAPPING, MYF(0), path, map->error);
  }
  VOID(pthread_mutex_unlock(&LOCK_mapped_file));
  return map;
#else
  return NULL;
#endif
}

/*
** free the map if there are no more users for it
*/

void unmap_file(mapped_files *map)
{
#ifdef HAVE_MMAP
  VOID(pthread_mutex_lock(&LOCK_mapped_file));
  if (!map->use_count--)
    delete map;
  VOID(pthread_mutex_unlock(&LOCK_mapped_file));
#endif
}

/*****************************************************************************
** Instansiate templates
*****************************************************************************/

#ifdef HAVE_EXPLICIT_TEMPLATE_INSTANTIATION
/* Used templates */
template class I_List<mapped_files>;
template class I_List_iterator<mapped_files>;
#endif