The unit test pfs_instr-t:
- generates a very long (10,000) bytes file name
- calls find_or_create_file.
This leads to a buffer overflow in mysys in my_realpath(),
because my_realpath and mysys file APIs in general do not
test for input parameters: mysys assumes every file name
is less that FN_REFLEN in length.
Calling find_or_create_file with a very long file name is likely
to happen when instrumenting third party code that does not use mysys,
so this test is legitimate.
The fix is to make find_or_create_file in the performance schema
more robust in this case.
Fixed the missing initialization of locker_lost.
This fix is not strictly necessary, but is desirable to re-align the code
from 5.5 and 6.0, and reduce the spurious code differences.
This will facilitate maintenance and help to apply patches cleanly, for merges.
Before this fix, the performance schema file instrumentation would treat:
- a relative path to a file
- an absolute path to the same file
as two different files.
This would lead to:
- separate aggregation counters
- file leaks when a file is removed.
With this fix, a relative and absolute path are resolved to the same file instrument.
