summaryrefslogtreecommitdiffstats
path: root/sql/discover.cc
blob: 201169357a25ef56e1f6fa4a9657a149776e9239 (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
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
/* Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
   Copyright (c) 2009, 2022, MariaDB Corporation.

   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 02110-1335  USA */


/**
  @file

  @brief
  Functions for discover of frm file from handler
*/

#include "mariadb.h"
#include "sql_priv.h"
#include "unireg.h"
#include "discover.h"
#include <my_dir.h>

/**
  Read the contents of a .frm file.

  frmdata and len are set to 0 on error.

  @param name           path to table-file "db/name"
  @param frmdata        frm data
  @param len            length of the read frmdata

  @retval
    0	ok
  @retval
    1	Could not open file
  @retval
    2    Could not stat file
  @retval
    3    Could not allocate data for read.  Could not read file
*/

int readfrm(const char *name, const uchar **frmdata, size_t *len)
{
  int    error;
  char	 index_file[FN_REFLEN];
  File	 file;
  size_t read_len;
  uchar *read_data;
  MY_STAT state;  
  DBUG_ENTER("readfrm");
  DBUG_PRINT("enter",("name: '%s'",name));
  
  *frmdata= NULL;      // In case of errors
  *len= 0;
  error= 1;
  if ((file= mysql_file_open(key_file_frm,
                             fn_format(index_file, name, "", reg_ext,
                               MY_UNPACK_FILENAME|MY_APPEND_EXT),
                             O_RDONLY | O_SHARE,
                             MYF(0))) < 0)
    goto err_end; 
  
  // Get length of file
  error= 2;
  if (mysql_file_fstat(file, &state, MYF(0)))
    goto err;
  MSAN_STAT_WORKAROUND(&state);
  read_len= (size_t)MY_MIN(FRM_MAX_SIZE, state.st_size); // safety

  // Read whole frm file
  error= 3;
  if (!(read_data= (uchar*)my_malloc(key_memory_frm_string, read_len,
                                     MYF(MY_WME))))
    goto err;
  if (mysql_file_read(file, read_data, read_len, MYF(MY_NABP)))
  {
    my_free(read_data);
    goto err;
  }

  // Setup return data
  *frmdata= (uchar*) read_data;
  *len= read_len;
  error= 0;
  
 err:
  (void) mysql_file_close(file, MYF(MY_WME));
  
 err_end:		      /* Here when no file */
  DBUG_RETURN (error);
} /* readfrm */


/*
  Write the content of a frm data pointer to a frm or par file.

  @param path           full path to table-file "db/name.frm" or .par
  @param db             Database name. Only used for my_error()
  @param table          Table name. Only used for my_error()
  @param data           data to write to file
  @param len            length of the data

  @retval
    0	ok
  @retval
    <> 0    Could not write file. In this case the file is not created
*/

int writefile(const char *path, const char *db, const char *table,
              bool tmp_table, const uchar *data, size_t len)
{
  int error;
  int create_flags= O_RDWR | O_TRUNC;
  DBUG_ENTER("writefile");
  DBUG_PRINT("enter",("name: '%s' len: %lu ",path, (ulong) len));

  if (tmp_table)
    create_flags|= O_EXCL | O_NOFOLLOW;

  File file= mysql_file_create(key_file_frm, path,
                               CREATE_MODE, create_flags, MYF(0));

  if (unlikely((error= file < 0)))
  {
    if (my_errno == ENOENT)
      my_error(ER_BAD_DB_ERROR, MYF(0), db);
    else
      my_error(ER_CANT_CREATE_TABLE, MYF(0), db, table, my_errno);
  }
  else
  {
    error= (int)mysql_file_write(file, data, len, MYF(MY_WME | MY_NABP));

    if (!error && !tmp_table && opt_sync_frm)
        error= mysql_file_sync(file, MYF(MY_WME)) ||
             my_sync_dir_by_file(path, MYF(MY_WME));

    error|= mysql_file_close(file, MYF(MY_WME));
    if (error)
      my_delete(path, MYF(0));
  }
  DBUG_RETURN(error);
} /* writefile */


static inline void advance(FILEINFO* &from, FILEINFO* &to,
                           FILEINFO* cur, bool &skip)
{
  if (skip)                   // if not copying
    from= cur;                //   just advance the start pointer
  else                        // if copying
    if (to == from)           //   but to the same place, not shifting the data
      from= to= cur;          //     advance both pointers
    else                      //   otherwise
      while (from < cur)      //     have to copy [from...cur) to [to...)
        *to++ = *from++;
  skip= false;
}

/**
  Go through the directory listing looking for files with a specified
  extension and add them to the result list

  @details
  This function may be called many times on the same directory listing
  but with different extensions. To avoid discovering the same table twice,
  whenever a table file is discovered, all files with the same name
  (independently from the extensions) are removed from the list.

  Example: the list contained
     { "db.opt", "t1.MYD", "t1.MYI", "t1.frm", "t2.ARZ", "t3.ARZ", "t3.frm" }
  on discovering all ".frm" files, tables "t1" and "t3" will be found,
  and list will become
     { "db.opt", "t2.ARZ" }
  and now ".ARZ" discovery can discover the table "t2"

  @note
  This function assumes that the directory listing is sorted alphabetically.

  @note  Partitioning makes this more complicated. A partitioned table t1 might
  have files, like t1.frm, t1#P#part1.ibd, t1#P#foo.ibd, etc.
  That means we need to compare file names only up to the first '#' or '.'
  whichever comes first.
*/
int extension_based_table_discovery(MY_DIR *dirp, const char *ext_meta,
                                    handlerton::discovered_list *result)
{
  CHARSET_INFO *cs= character_set_filesystem;
  size_t ext_meta_len= strlen(ext_meta);
  FILEINFO *from, *to, *cur, *end;
  bool skip= false;
  
  from= to= cur= dirp->dir_entry;
  end= cur + dirp->number_of_files;
  while (cur < end)
  {
    char *octothorp= strchr(cur->name + 1, '#');
    char *ext= strchr(octothorp ? octothorp : cur->name, FN_EXTCHAR);

    if (ext)
    {
      size_t len= (octothorp ? octothorp : ext) - cur->name;
      if (from != cur &&
          (strlen(from->name) <= len ||
           cs->strnncoll(from->name, len, cur->name, len) ||
           (from->name[len] != FN_EXTCHAR && from->name[len] != '#')))
        advance(from, to, cur, skip);

      if (cs->strnncoll(ext, strlen(ext),
                        ext_meta, ext_meta_len) == 0)
      {
        *ext = 0;
        if (result->add_file(cur->name))
          return 1;
        *ext = FN_EXTCHAR;
        skip= true; // table discovered, skip all files with the same name
      }
    }
    else
    {
      advance(from, to, cur, skip);
      from++;
    }

    cur++;
  }
  advance(from, to, cur, skip);
  dirp->number_of_files= to - dirp->dir_entry;
  return 0;
}

/**
  Simple, not reusable file-based table discovery

  @details
  simplified version of extension_based_table_discovery(), that does not
  modify the list of files. It cannot be called many times for the same
  directory listing, otherwise it'll produce duplicate results.
*/
int ext_table_discovery_simple(MY_DIR *dirp,
                               handlerton::discovered_list *result)
{
  CHARSET_INFO *cs= character_set_filesystem;
  FILEINFO *cur, *end;
  
  cur= dirp->dir_entry;
  end= cur + dirp->number_of_files;
  while (cur < end)
  {
    char *ext= strrchr(cur->name, FN_EXTCHAR);

    if (ext)
    {
      if (cs->strnncoll(ext, strlen(ext),
                        reg_ext, reg_ext_length) == 0)
      {
        *ext = 0;
        if (result->add_file(cur->name))
          return 1;
      }
    }
    cur++;
  }
  return 0;
}