summaryrefslogtreecommitdiff
path: root/sql/datadict.cc
blob: 287e8568d90194a9f121c5c3aac835790d7e242d (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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
/* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.

   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include <my_global.h>
#include "datadict.h"
#include "sql_priv.h"
#include "sql_class.h"
#include "sql_table.h"

static int read_string(File file, uchar**to, size_t length)
{
  DBUG_ENTER("read_string");

  my_free(*to);
  if (!(*to= (uchar*) my_malloc(length+1,MYF(MY_WME))) ||
      mysql_file_read(file, *to, length, MYF(MY_NABP)))
  {
     my_free(*to);
    *to= 0;
    DBUG_RETURN(1);
  }
  *((char*) *to+length)= '\0'; // C-style safety
  DBUG_RETURN (0);
}


/**
  Check type of .frm if we are not going to parse it.

  @param[in]  thd   The current session.
  @param[in]  path  path to FRM file.
  @param[out] dbt   db_type of the table if FRMTYPE_TABLE, otherwise undefined.

  @retval  FRMTYPE_ERROR        error
  @retval  FRMTYPE_TABLE        table
  @retval  FRMTYPE_VIEW         view
*/

frm_type_enum dd_frm_type(THD *thd, char *path, enum legacy_db_type *dbt)
{
  File file;
  uchar header[10];     //"TYPE=VIEW\n" it is 10 characters
  size_t error;
  frm_type_enum type= FRMTYPE_ERROR;
  DBUG_ENTER("dd_frm_type");

  *dbt= DB_TYPE_UNKNOWN;

  if ((file= mysql_file_open(key_file_frm, path, O_RDONLY | O_SHARE, MYF(0))) < 0)
    DBUG_RETURN(FRMTYPE_ERROR);
  error= mysql_file_read(file, (uchar*) header, sizeof(header), MYF(MY_NABP));

  if (error)
    goto err;
  if (!strncmp((char*) header, "TYPE=VIEW\n", sizeof(header)))
  {
    type= FRMTYPE_VIEW;
    goto err;
  }

  type= FRMTYPE_TABLE;

  /*
    This is just a check for DB_TYPE. We'll return default unknown type
    if the following test is true (arg #3). This should not have effect
    on return value from this function (default FRMTYPE_TABLE)
  */
  if (!is_binary_frm_header(header))
    goto err;

  *dbt= (enum legacy_db_type) (uint) *(header + 3);

  if (*dbt >= DB_TYPE_FIRST_DYNAMIC) /* read the true engine name */
  {
    MY_STAT state;  
    uchar *frm_image= 0;
    uint n_length;

    if (mysql_file_fstat(file, &state, MYF(MY_WME)))
      goto err;

    if (mysql_file_seek(file, 0, SEEK_SET, MYF(MY_WME)))
      goto err;

    if (read_string(file, &frm_image, state.st_size))
      goto err;

    if ((n_length= uint4korr(frm_image+55)))
    {
      uint record_offset= uint2korr(frm_image+6)+
                      ((uint2korr(frm_image+14) == 0xffff ?
                        uint4korr(frm_image+47) : uint2korr(frm_image+14)));
      uint reclength= uint2korr(frm_image+16);

      uchar *next_chunk= frm_image + record_offset + reclength;
      uchar *buff_end= next_chunk + n_length;
      uint connect_string_length= uint2korr(next_chunk);
      next_chunk+= connect_string_length + 2;
      if (next_chunk + 2 < buff_end)
      {
        uint str_db_type_length= uint2korr(next_chunk);
        LEX_STRING name;
        name.str= (char*) next_chunk + 2;
        name.length= str_db_type_length;
        plugin_ref tmp_plugin= ha_resolve_by_name(thd, &name, false);
        if (tmp_plugin)
          *dbt= plugin_data(tmp_plugin, handlerton *)->db_type;
        else
          *dbt= DB_TYPE_UNKNOWN;
      }
    }

    my_free(frm_image);
  }

  /* Probably a table. */
err:
  mysql_file_close(file, MYF(MY_WME));
  DBUG_RETURN(type);
}


/*
  Regenerate a metadata locked table.

  @param  thd   Thread context.
  @param  db    Name of the database to which the table belongs to.
  @param  name  Table name.
  @param  path  For temporary tables only - path to table files.
                Otherwise NULL (the path is calculated from db and table names).

  @retval  FALSE  Success.
  @retval  TRUE   Error.
*/

bool dd_recreate_table(THD *thd, const char *db, const char *table_name,
                       const char *path)
{
  bool error= TRUE;
  HA_CREATE_INFO create_info;
  char path_buf[FN_REFLEN + 1];
  DBUG_ENTER("dd_recreate_table");

  memset(&create_info, 0, sizeof(create_info));

  if (path)
    create_info.options|= HA_LEX_CREATE_TMP_TABLE;
  else
  {
    build_table_filename(path_buf, sizeof(path_buf) - 1,
                         db, table_name, "", 0);
    path= path_buf;

    /* There should be a exclusive metadata lock on the table. */
    DBUG_ASSERT(thd->mdl_context.is_lock_owner(MDL_key::TABLE, db, table_name,
                                               MDL_EXCLUSIVE));
  }

  /* Attempt to reconstruct the table. */
  error= ha_create_table(thd, path, db, table_name, &create_info, NULL);

  DBUG_RETURN(error);
}