Manticore leaves lots of files in /tmp

[offlinemark]

When the analyzed program called open and the first byte of the filename is symbolic, Manticore creates a /tmp file, fills it with 64 '+' and uses that as the backing file.

• Could manticore clean up after itself? this can probably be done using tempfile.TemporaryFile rather than tempfile.mkstemp in linux.py:SLinux.sys_open
• Does manticore need to have a file on disk at all? could the symbolic file exist only in memory?

[MrSynAckSter-zz]

I changed mkstmp to tempfile.TemporaryFile in 221f149. I ran it against all of the tests in /tests/native, and there didn't seem to be errors. My only concern is that if tempfile.TemporaryFile is ever garbage collected, the file cease to exist. I don't know enough about how Manticore handles these files to say whether or not that possible, but running it against a few random binaries that use sys_open doesn't seem to cause any issues of that nature. If you guys can suggest anything else to do in order to ensure this change is safe, let me know.

[ehennenfent]

https://github.com/trailofbits/manticore/wiki/Ideas