Fixed memory leak in ODBC::GetParametersFromArray#8
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Awesome find. Thank you for your work. Released v0.6.10 to npm. Cheers! |
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Dec 17, 2020
Fixing both an SQL_FLOAT issue and boundRow garbage Data Fixes wankdanker#67 Fixes wankdanker#8
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The bug occurs when a query is being executed with usage of parameters array where array is empty. Something along the lines of
In such cases,
ODBC::GetParametersFromArrayis being executed and sincevalues->Length()is equal to 0, the call tomalloceffectively becomesmalloc(0). Behavior of such call is not strictly defined. C99 standard states that either a null pointer should be returned or the call should behave as if the requested size was nonzero and a unique pointer is returned with the exception that the address should not be accessed (PDF Warning - ISO/IEC 9899:TC2, section 7.20.3, page 313).As it stands,
glibcdisplays the latter behavior, additionally defining a minimum allocated size.The actual cause of the leak is the fact that in all instances where the parameter array returned by
ODBC::GetParametersFromArrayis freed, it is only done under condition that there were more than 0 parameters in the query - example.Given enough time and enough queries, those several lost bytes did pile up.