1/* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
2
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License as published by
5 the Free Software Foundation; version 2 of the License.
6
7 This program is distributed in the hope that it will be useful,
8 but WITHOUT ANY WARRANTY; without even the implied warranty of
9 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 GNU General Public License for more details.
11
12 You should have received a copy of the GNU General Public License
13 along with this program; if not, write to the Free Software
14 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
15
16#include "mariadb.h"
17#include "datadict.h"
18#include "sql_priv.h"
19#include "sql_class.h"
20#include "sql_table.h"
21#include "ha_sequence.h"
22
23static int read_string(File file, uchar**to, size_t length)
24{
25 DBUG_ENTER("read_string");
26
27 /* This can't use MY_THREAD_SPECIFIC as it's used on server start */
28 if (!(*to= (uchar*) my_malloc(length+1,MYF(MY_WME))) ||
29 mysql_file_read(file, *to, length, MYF(MY_NABP)))
30 {
31 my_free(*to);
32 *to= 0;
33 DBUG_RETURN(1);
34 }
35 *((char*) *to+length)= '\0'; // C-style safety
36 DBUG_RETURN (0);
37}
38
39
40/**
41 Check type of .frm if we are not going to parse it.
42
43 @param[in] thd The current session.
44 @param[in] path path to FRM file.
45 @param[in/out] engine_name table engine name (length < NAME_CHAR_LEN)
46
47 engine_name is a LEX_CSTRING, where engine_name->str must point to
48 a buffer of at least NAME_CHAR_LEN+1 bytes.
49 If engine_name is 0, then the function will only test if the file is a
50 view or not
51
52 @param[out] is_sequence 1 if table is a SEQUENCE, 0 otherwise
53
54 @retval TABLE_TYPE_UNKNOWN error - file can't be opened
55 @retval TABLE_TYPE_NORMAL table
56 @retval TABLE_TYPE_SEQUENCE sequence table
57 @retval TABLE_TYPE_VIEW view
58*/
59
60Table_type dd_frm_type(THD *thd, char *path, LEX_CSTRING *engine_name,
61 bool *is_sequence)
62{
63 File file;
64 uchar header[40]; //"TYPE=VIEW\n" it is 10 characters
65 size_t error;
66 Table_type type= TABLE_TYPE_UNKNOWN;
67 uchar dbt;
68 DBUG_ENTER("dd_frm_type");
69
70 *is_sequence= 0;
71
72 if ((file= mysql_file_open(key_file_frm, path, O_RDONLY | O_SHARE, MYF(0)))
73 < 0)
74 DBUG_RETURN(TABLE_TYPE_UNKNOWN);
75
76 /*
77 We return TABLE_TYPE_NORMAL if we can open the .frm file. This allows us
78 to drop a bad .frm file with DROP TABLE
79 */
80 type= TABLE_TYPE_NORMAL;
81
82 /*
83 Initialize engine name in case we are not able to find it out
84 The cast is safe, as engine_name->str points to a usable buffer.
85 */
86 if (engine_name)
87 {
88 engine_name->length= 0;
89 ((char*) (engine_name->str))[0]= 0;
90 }
91
92 if (unlikely((error= mysql_file_read(file, (uchar*) header, sizeof(header), MYF(MY_NABP)))))
93 goto err;
94
95 if (unlikely((!strncmp((char*) header, "TYPE=VIEW\n", 10))))
96 {
97 type= TABLE_TYPE_VIEW;
98 goto err;
99 }
100
101 /* engine_name is 0 if we only want to know if table is view or not */
102 if (!engine_name)
103 goto err;
104
105 if (!is_binary_frm_header(header))
106 goto err;
107
108 dbt= header[3];
109
110 if (((header[39] >> 4) & 3) == HA_CHOICE_YES)
111 {
112 DBUG_PRINT("info", ("Sequence found"));
113 *is_sequence= 1;
114 }
115
116 /* cannot use ha_resolve_by_legacy_type without a THD */
117 if (thd && dbt < DB_TYPE_FIRST_DYNAMIC)
118 {
119 handlerton *ht= ha_resolve_by_legacy_type(thd, (enum legacy_db_type)dbt);
120 if (ht)
121 {
122 *engine_name= hton2plugin[ht->slot]->name;
123 goto err;
124 }
125 }
126
127 /* read the true engine name */
128 {
129 MY_STAT state;
130 uchar *frm_image= 0;
131 uint n_length;
132
133 if (mysql_file_fstat(file, &state, MYF(MY_WME)))
134 goto err;
135
136 if (mysql_file_seek(file, 0, SEEK_SET, MYF(MY_WME)))
137 goto err;
138
139 if (read_string(file, &frm_image, (size_t)state.st_size))
140 goto err;
141
142 if ((n_length= uint4korr(frm_image+55)))
143 {
144 uint record_offset= uint2korr(frm_image+6)+
145 ((uint2korr(frm_image+14) == 0xffff ?
146 uint4korr(frm_image+47) : uint2korr(frm_image+14)));
147 uint reclength= uint2korr(frm_image+16);
148
149 uchar *next_chunk= frm_image + record_offset + reclength;
150 uchar *buff_end= next_chunk + n_length;
151 uint connect_string_length= uint2korr(next_chunk);
152 next_chunk+= connect_string_length + 2;
153 if (next_chunk + 2 < buff_end)
154 {
155 uint len= uint2korr(next_chunk);
156 if (len <= NAME_CHAR_LEN)
157 {
158 /*
159 The following cast is safe as the caller has allocated buffer
160 and it's up to this function to generate the name.
161 */
162 strmake((char*) engine_name->str, (char*)next_chunk + 2,
163 engine_name->length= len);
164 }
165 }
166 }
167
168 my_free(frm_image);
169 }
170
171 /* Probably a table. */
172err:
173 mysql_file_close(file, MYF(MY_WME));
174 DBUG_RETURN(type);
175}
176
177
178/*
179 Regenerate a metadata locked table.
180
181 @param thd Thread context.
182 @param db Name of the database to which the table belongs to.
183 @param name Table name.
184 @param path For temporary tables only - path to table files.
185 Otherwise NULL (the path is calculated from db and table names).
186
187 @retval FALSE Success.
188 @retval TRUE Error.
189*/
190
191bool dd_recreate_table(THD *thd, const char *db, const char *table_name,
192 const char *path)
193{
194 bool error= TRUE;
195 HA_CREATE_INFO create_info;
196 char path_buf[FN_REFLEN + 1];
197 DBUG_ENTER("dd_recreate_table");
198
199 memset(&create_info, 0, sizeof(create_info));
200
201 if (path)
202 create_info.options|= HA_LEX_CREATE_TMP_TABLE;
203 else
204 {
205 build_table_filename(path_buf, sizeof(path_buf) - 1,
206 db, table_name, "", 0);
207 path= path_buf;
208
209 /* There should be a exclusive metadata lock on the table. */
210 DBUG_ASSERT(thd->mdl_context.is_lock_owner(MDL_key::TABLE, db, table_name,
211 MDL_EXCLUSIVE));
212 }
213
214 /* Attempt to reconstruct the table. */
215 error= ha_create_table(thd, path, db, table_name, &create_info, NULL);
216
217 DBUG_RETURN(error);
218}
219
220