Version 6.0.6

Bugs Fixed

• On 32 bit platforms such as i586 and armv7, requests proxied to a daemon process group would fail after the connect timeout with the error:

  WSGI0116: Unable to connect to WSGI daemon process 'name' on
  '(null)' after multiple attempts as listener backlog limit was
  exceeded or the socket does not exist.
  

  where the daemon process group socket path was logged as (null), even though the daemon processes had started correctly and their listener socket existed. This was a regression introduced in version 6.0.0 when the source code was split into multiple files and did not affect 64 bit platforms.

  The cause was that a subset of the source files included the Apache headers before Python.h. The Python pyconfig.h header defines _FILE_OFFSET_BITS to 64, which on 32 bit Linux changes the size of the C library rlim_t type from 4 to 8 bytes. As the internal structure describing a daemon process group contains rlim_t fields ahead of the socket path and other fields, source files which saw the Apache headers first had a different layout for that structure than those which saw Python.h first. The code connecting to the daemon process therefore read the socket path from the wrong offset, yielding a NULL pointer, and the connection was attempted to an empty socket path and refused. The same mismatch also caused Apache child processes to skip closing their inherited copy of the daemon listener socket.

  All source and header files now include wsgi_python.h and wsgi_apache.h first, in that order, before any other headers, and wsgi_apache.h itself now includes wsgi_python.h before any Apache header, so that Python.h is always the first header seen by every compilation unit, as required by the Python C API. This ensures every compilation unit agrees on the layout of shared structures regardless of platform word size.