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-rw-r--r--mysql-test/r/type_decimal.result8
-rw-r--r--mysql-test/t/type_decimal.test13
-rw-r--r--sql/my_decimal.cc43
3 files changed, 51 insertions, 13 deletions
diff --git a/mysql-test/r/type_decimal.result b/mysql-test/r/type_decimal.result
index efac8cbe580..fa7bf91b113 100644
--- a/mysql-test/r/type_decimal.result
+++ b/mysql-test/r/type_decimal.result
@@ -683,6 +683,7 @@ select * from t1;
a b
123.12345 123.1
drop table t1;
+End of 4.1 tests
CREATE TABLE t1
(EMPNUM CHAR(3) NOT NULL,
HOURS DECIMAL(5));
@@ -799,3 +800,10 @@ SELECT ROUND(qty,3), dps, ROUND(qty,dps) FROM t1;
ROUND(qty,3) dps ROUND(qty,dps)
1.133 3 1.133
DROP TABLE t1;
+create table t1 (f1 decimal(6,6),f2 decimal(6,6) zerofill);
+insert into t1 values (-0.123456,0.123456);
+select group_concat(f1),group_concat(f2) from t1;
+group_concat(f1) group_concat(f2)
+-0.123456 0.123456
+drop table t1;
+End of 5.0 tests
diff --git a/mysql-test/t/type_decimal.test b/mysql-test/t/type_decimal.test
index 5538f19f5f9..458583fca81 100644
--- a/mysql-test/t/type_decimal.test
+++ b/mysql-test/t/type_decimal.test
@@ -278,7 +278,7 @@ update t1 set b=a;
select * from t1;
drop table t1;
-# End of 4.1 tests
+--echo End of 4.1 tests
#
# Test for BUG#8397: decimal type in subselects (Item_cache_decimal)
@@ -408,3 +408,14 @@ INSERT INTO t1 VALUES (1.1325,3);
SELECT ROUND(qty,3), dps, ROUND(qty,dps) FROM t1;
DROP TABLE t1;
+
+#
+# Bug #31227: memory overrun with decimal (6,6) and zerofill and group_concat
+# valgrind will complain about this (the group_concat(f2)) on unpatched mysqld.
+#
+create table t1 (f1 decimal(6,6),f2 decimal(6,6) zerofill);
+insert into t1 values (-0.123456,0.123456);
+select group_concat(f1),group_concat(f2) from t1;
+drop table t1;
+
+--echo End of 5.0 tests
diff --git a/sql/my_decimal.cc b/sql/my_decimal.cc
index 1f0ebf32795..54cef6abdb5 100644
--- a/sql/my_decimal.cc
+++ b/sql/my_decimal.cc
@@ -68,24 +68,43 @@ int decimal_operation_results(int result)
}
-/*
- Converting decimal to string
-
- SYNOPSIS
- my_decimal2string()
-
- return
- E_DEC_OK
- E_DEC_TRUNCATED
- E_DEC_OVERFLOW
- E_DEC_OOM
+/**
+ @brief Converting decimal to string
+
+ @details Convert given my_decimal to String; allocate buffer as needed.
+
+ @param[in] mask what problems to warn on (mask of E_DEC_* values)
+ @param[in] d the decimal to print
+ @param[in] fixed_prec overall number of digits if ZEROFILL, 0 otherwise
+ @param[in] fixed_dec number of decimal places (if fixed_prec != 0)
+ @param[in] filler what char to pad with (ZEROFILL et al.)
+ @param[out] *str where to store the resulting string
+
+ @return error coce
+ @retval E_DEC_OK
+ @retval E_DEC_TRUNCATED
+ @retval E_DEC_OVERFLOW
+ @retval E_DEC_OOM
*/
int my_decimal2string(uint mask, const my_decimal *d,
uint fixed_prec, uint fixed_dec,
char filler, String *str)
{
- int length= (fixed_prec ? (fixed_prec + 1) : my_decimal_string_length(d));
+ /*
+ Calculate the size of the string: For DECIMAL(a,b), fixed_prec==a
+ holds true iff the type is also ZEROFILL, which in turn implies
+ UNSIGNED. Hence the buffer for a ZEROFILLed value is the length
+ the user requested, plus one for a possible decimal point, plus
+ one if the user only wanted decimal places, but we force a leading
+ zero on them. Because the type is implicitly UNSIGNED, we do not
+ need to reserve a character for the sign. For all other cases,
+ fixed_prec will be 0, and my_decimal_string_length() will be called
+ instead to calculate the required size of the buffer.
+ */
+ int length= (fixed_prec
+ ? (fixed_prec + ((fixed_prec == fixed_dec) ? 1 : 0) + 1)
+ : my_decimal_string_length(d));
int result;
if (str->alloc(length))
return check_result(mask, E_DEC_OOM);