[OSM-dev] Static analysis with coverity of osm2pgsql and mod_tile

[Kai Krueger]

Hello everyone,

in order to try and help ensure and improve the quality of the osm 
rendering stack, I have registered osm2pglsql and mod_tile / renderd on 
Coverity[1] for their static analysis tools.

Static analysis tools check the source code during compilation time to 
try and find various bugs, such as memory leaks, null pointer 
dereference, potential buffer overflows or dead-locks. It analyses the 
control flow of the source code and identifies routes through the code 
which can lead to the various issues. As such, it is particularly useful 
for finding errors on obscure control flow paths (e.g. error path ways) 
that during typical operations aren't executed and thus are hard to find 
with dynamic testing.

It has found 32 issues in osm2pgsql and 39 in renderd. I haven't worked 
through them all yet and presumably a number of them are false 
positives. But a bunch of them do appear to be genuine issues, albeit 
luckily most of them do appear to be on paths that during normal 
operations shouldn't be executed.

If anyone else is interested in more detailed results, I think I should 
be able to add you as users to the projects so that you can then access 
the data coverity provides.

While coverity is normally an expensive paid-for software, they offer 
their services free of charge to open source projects [2] and quite a 
number of large OS projects use it, including the linux kernel and 
postgreSQL. As far as I can tell, it supports C, C++ and Java as source 
languages.

Perhaps other OSM related projects like JOSM or Mapnik would also be 
interested in using coverity?

Kai



[1] http://www.coverity.com/
[2] http://scan.coverity.com/