Re: bk commit into 5.1 tree (antony:1.2600) BUG#30671

[Sergei Golubchik]

Hi!

On Oct 30, antony@stripped wrote:
> ChangeSet@stripped, 2007-10-30 13:38:48-07:00, antony@stripped +3 -0
>   Bug#30671
>     "ALTER SERVER causes the server to crash"
>     An attempt to pass NULL into strcmp() caused crash.
> 
>   sql/sql_servers.cc@stripped, 2007-10-30 13:38:45-07:00, antony@stripped +12
> -12
>     bug30671
>       existing->value may be NULL which will cause crash when user attempts
>       to alter value.

existing values cannot really be null.
See how they set in prepare_server_struct_for_insert().

And see how they're read from the table in
get_server_from_table_to_cache() - all fields are set to an empty
string, if they're unset. With the one exception - socket is set to
NULL.

This is where it crashes in this bug - on socket.

Note that the behaviour is inconsistent - the socket is set to an empty
string in prepare_server_struct_for_insert / CREATE SERVER. But it's set
to NULL in get_server_from_table_to_cache() - on ALTER or server
restart.

The inconsistency is certainly a bug, and I don't see a reason for
socket to be NULL at all. Make it an empty string in
get_server_from_table_to_cache(), just like all other fields are.
 
Regards / Mit vielen Grüssen,
Sergei

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