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Bug#26711 "Binary content 0x00 sometimes becomes 0x5C 0x00 after dump/load"

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Problem: "SELECT INTO OUTFILE" created incorrect dumps for BLOBs,
so "LOAD DATA" later incorrectly interpreted 0x5C as the second
byte of a multi-byte sequence, instead of escape character.
Fix: adding escaping of multi-byte heads.


mysql-test/r/ctype_big5.result:
  Adding test case
mysql-test/t/ctype_big5.test:
  Adding test case
sql/sql_class.cc:
  Add escape characters before multi-byte heads.
strings/ctype-big5.c:
  Flagging character set as dangerous for escaping.
strings/ctype-gbk.c:
  Flagging character set as dangerous for escaping.
strings/ctype-sjis.c:
  Flagging character set as dangerous for escaping.
This commit is contained in:
unknown
2007-06-07 13:16:49 +05:00
parent 4bdbc3396e
commit 2971d645c1
6 changed files with 89 additions and 13 deletions
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59
sql/sql_class.cc
View File

@@ -1221,6 +1221,11 @@ select_export::prepare(List<Item> &list, SELECT_LEX_UNIT *u)
}
#define NEED_ESCAPING(x) ((int) (uchar) (x) == escape_char || \
(int) (uchar) (x) == field_sep_char || \
(int) (uchar) (x) == line_sep_char || \
!(x))
bool select_export::send_data(List<Item> &items)
{
@@ -1280,14 +1285,20 @@ bool select_export::send_data(List<Item> &items)
used_length=res->length();
if (result_type == STRING_RESULT && escape_char != -1)
{
char *pos,*start,*end;
char *pos, *start, *end;
CHARSET_INFO *res_charset= res->charset();
CHARSET_INFO *character_set_client= thd->variables.
character_set_client;
bool check_second_byte= (res_charset == &my_charset_bin) &&
character_set_client->
escape_with_backslash_is_dangerous;
DBUG_ASSERT(character_set_client->mbmaxlen == 2 ||
!character_set_client->escape_with_backslash_is_dangerous);
for (start=pos=(char*) res->ptr(),end=pos+used_length ;
pos != end ;
pos++)
{
#ifdef USE_MB
CHARSET_INFO *res_charset=res->charset();
if (use_mb(res_charset))
{
int l;
@@ -1298,9 +1309,45 @@ bool select_export::send_data(List<Item> &items)
}
}
#endif
if ((int) *pos == escape_char || (int) *pos == field_sep_char ||
(int) *pos == line_sep_char || !*pos)
{
/*
Special case when dumping BINARY/VARBINARY/BLOB values
for the clients with character sets big5, cp932, gbk and sjis,
which can have the escape character (0x5C "\" by default)
as the second byte of a multi-byte sequence.
If
- pos[0] is a valid multi-byte head (e.g 0xEE) and
- pos[1] is 0x00, which will be escaped as "\0",
then we'll get "0xEE + 0x5C + 0x30" in the output file.
If this file is later loaded using this sequence of commands:
mysql> create table t1 (a varchar(128)) character set big5;
mysql> LOAD DATA INFILE 'dump.txt' INTO TABLE t1;
then 0x5C will be misinterpreted as the second byte
of a multi-byte character "0xEE + 0x5C", instead of
escape character for 0x00.
To avoid this confusion, we'll escape the multi-byte
head character too, so the sequence "0xEE + 0x00" will be
dumped as "0x5C + 0xEE + 0x5C + 0x30".
Note, in the condition below we only check if
mbcharlen is equal to 2, because there are no
character sets with mbmaxlen longer than 2
and with escape_with_backslash_is_dangerous set.
DBUG_ASSERT before the loop makes that sure.
*/
if (NEED_ESCAPING(*pos) ||
(check_second_byte &&
my_mbcharlen(character_set_client, (uchar) *pos) == 2 &&
pos + 1 < end &&
NEED_ESCAPING(pos[1])))
{
char tmp_buff[2];
tmp_buff[0]= escape_char;
tmp_buff[1]= *pos ? *pos : '0';