Analysis: JSON_VALUE() returns "null" string instead of NULL pointer.
Fix: When the type is JSON_VALUE_NULL (which is also a scalar) set
null_value to true and return 0 instead of returning string.
Unlike GCC, clang could optimize away alloca() and thus the
ALLOCATE_MEM_ON_STACK() instrumentation. To make it harder, let us
invoke a non-inline function on the entire allocated buffer.
This commit is a fixup for MDEV-28762
Analysis: Some recursive json functions dont check for stack control
Fix: Add check_stack_overrun(). The last argument is NULL because it is not
used
Hybrid functions (IF, COALESCE, etc) did not preserve the JSON property
from their arguments. The same problem was repeatable for single row subselects.
The problem happened because the method Item::is_json_type() was inconsistently
implemented across the Item hierarchy. For example, Item_hybrid_func
and Item_singlerow_subselect did not override is_json_type().
Solution:
- Removing Item::is_json_type()
- Implementing specific JSON type handlers:
Type_handler_string_json
Type_handler_varchar_json
Type_handler_tiny_blob_json
Type_handler_blob_json
Type_handler_medium_blob_json
Type_handler_long_blob_json
- Reusing the existing data type infrastructure to pass JSON
type handlers across all item types, including classes Item_hybrid_func
and Item_singlerow_subselect. Note, these two classes themselves do not
need any changes!
- Extending the data type infrastructure so data types can inherit
their properties (e.g. aggregation rules) from their base data types.
E.g. VARCHAR/JSON acts as VARCHAR, LONGTEXT/JSON acts as LONGTEXT
when mixed to a non-JSON data type. This is done by:
- adding virtual method Type_handler::type_handler_base()
- adding a helper class Type_handler_pair
- refactoring Type_handler_hybrid_field_type methods
aggregate_for_result(), aggregate_for_min_max(),
aggregate_for_num_op() to use Type_handler_pair.
This change also fixes:
MDEV-27361 Hybrid functions with JSON arguments do not send format metadata
Also, adding mtr tests for JSON replication. It was not covered yet.
And the current patch changes the replication code slightly.
The easiest way to compile and test the server with UBSAN is to run:
./BUILD/compile-pentium64-ubsan
and then run mysql-test-run.
After this commit, one should be able to run this without any UBSAN
warnings. There is still a few compiler warnings that should be fixed
at some point, but these do not expose any real bugs.
The 'special' cases where we disable, suppress or circumvent UBSAN are:
- ref10 source (as here we intentionally do some shifts that UBSAN
complains about.
- x86 version of optimized int#korr() methods. UBSAN do not like unaligned
memory access of integers. Fixed by using byte_order_generic.h when
compiling with UBSAN
- We use smaller thread stack with ASAN and UBSAN, which forced me to
disable a few tests that prints the thread stack size.
- Verifying class types does not work for shared libraries. I added
suppression in mysql-test-run.pl for this case.
- Added '#ifdef WITH_UBSAN' when using integer arithmetic where it is
safe to have overflows (two cases, in item_func.cc).
Things fixed:
- Don't left shift signed values
(byte_order_generic.h, mysqltest.c, item_sum.cc and many more)
- Don't assign not non existing values to enum variables.
- Ensure that bool and enum values are properly initialized in
constructors. This was needed as UBSAN checks that these types has
correct values when one copies an object.
(gcalc_tools.h, ha_partition.cc, item_sum.cc, partition_element.h ...)
- Ensure we do not called handler functions on unallocated objects or
deleted objects.
(events.cc, sql_acl.cc).
- Fixed bugs in Item_sp::Item_sp() where we did not call constructor
on Query_arena object.
- Fixed several cast of objects to an incompatible class!
(Item.cc, Item_buff.cc, item_timefunc.cc, opt_subselect.cc, sql_acl.cc,
sql_select.cc ...)
- Ensure we do not do integer arithmetic that causes over or underflows.
This includes also ++ and -- of integers.
(Item_func.cc, Item_strfunc.cc, item_timefunc.cc, sql_base.cc ...)
- Added JSON_VALUE_UNITIALIZED to json_value_types and ensure that
value_type is initialized to this instead of to -1, which is not a valid
enum value for json_value_types.
- Ensure we do not call memcpy() when second argument could be null.
- Fixed that Item_func_str::make_empty_result() creates an empty string
instead of a null string (safer as it ensures we do not do arithmetic
on null strings).
Other things:
- Changed struct st_position to an OBJECT and added an initialization
function to it to ensure that we do not copy or use uninitialized
members. The change to a class was also motived that we used "struct
st_position" and POSITION randomly trough the code which was
confusing.
- Notably big rewrite in sql_acl.cc to avoid using deleted objects.
- Changed in sql_partition to use '^' instead of '-'. This is safe as
the operator is either 0 or 0x8000000000000000ULL.
- Added check for select_nr < INT_MAX in JOIN::build_explain() to
avoid bug when get_select() could return NULL.
- Reordered elements in POSITION for better alignment.
- Changed sql_test.cc::print_plan() to use pointers instead of objects.
- Fixed bug in find_set() where could could execute '1 << -1'.
- Added variable have_sanitizer, used by mtr. (This variable was before
only in 10.5 and up). It can now have one of two values:
ASAN or UBSAN.
- Moved ~Archive_share() from ha_archive.cc to ha_archive.h and marked
it virtual. This was an effort to get UBSAN to work with loaded storage
engines. I kept the change as the new place is better.
- Added in CONNECT engine COLBLK::SetName(), to get around a wrong cast
in tabutil.cpp.
- Added HAVE_REPLICATION around usage of rgi_slave, to get embedded
server to compile with UBSAN. (Patch from Marko).
- Added #ifdef for powerpc64 to avoid a bug in old gcc versions related
to integer arithmetic.
Changes that should not be needed but had to be done to suppress warnings
from UBSAN:
- Added static_cast<<uint16_t>> around shift to get rid of a LOT of
compiler warnings when using UBSAN.
- Had to change some '/' of 2 base integers to shift to get rid of
some compile time warnings.
Reviewed by:
- Json changes: Alexey Botchkov
- Charset changes in ctype-uca.c: Alexander Barkov
- InnoDB changes & Embedded server: Marko Mäkelä
- sql_acl.cc changes: Vicențiu Ciorbaru
- build_explain() changes: Sergey Petrunia
When first argument to the JSON_MERGE_PATCH was NULL and second - the
invalid JSON line, the error code was garbage. So it should be set to 0
initially.
Quick grouping is not supported for JSON_OBJECTAGG. The same for GROUP_CONCAT too
so make sure that Item::quick_group is set to FALSE. We need to make sure that in
the case of JSON_OBJECTAGG we don't create an index over grouping fields of
the temp table and update the result after each iteration.
Instead we should first sort the result in accordance to the
GROUP BY fields and then perform the grouping and
write the result to the temp table.
Item_func_json_extract did not implement val_decimal(),
so CAST(JSON_EXTRACT('{"x":true}', '$.x') AS DECIMAL) erroneously
returned 0 with a warning because of convertion from the string "true"
to decimal.
Implementing val_decimal(), so boolean values are correctly handled.
For DISTINCT to be handled with JSON_ARRAYAGG, we need to make sure
that the Unique tree also holds the NULL bytes of a table record
inside the node of the tree. This behaviour for JSON_ARRAYAGG is
different from GROUP_CONCAT because in GROUP_CONCAT we just reject
NULL values for columns.
Also introduced a comparator function for the unique tree to handle null
values for distinct inside JSON_ARRAYAGG.
We have to include NULL in the result which the GOUP_CONCAT doesn't
always do. Also converting should be done into another String instance
as these can be same.
The JSON_ARRAYAGG function extends the GROUP_CONCAT function and provides
a method of aggregating JSON results. The current implementation supports
DISTINCT and LIMIT but not ORDER BY (Oracle supports GROUP BY).
Adding GROUP BY support is possible but it requires some extra work as the
grouping appears to be done inside a temporary table that complicates
matters.
Added test cases that covert aggregation of all JSON types and JSON
validation for the generated results.
The MDEV-17262 commit 26432e49d3
was skipped. In Galera 4, the implementation would seem to require
changes to the streaming replication.
In the tests archive.rnd_pos main.profiling, disable_ps_protocol
for SHOW STATUS and SHOW PROFILE commands until MDEV-18974
has been fixed.
