Rename g_file_open() to g_file_open_rw(), and add a new g_file_open_ro()
call that wraps the common g_file_open_ex(file, 1, 0, 0, 0) idiom. This
will make the file access mode more explicit in the code.
Change all calls to g_file_open() to the _ro() or _rw() variant as
appropriate, and replace g_file_open_ex(file, 1, 0, 0, 0) with the _ro()
call.
Lastly, add tests for the two new calls to test_os_calls.c (code
courteously provided by matt335672).
When sesman used a standard TCP socket, we were guaranteed only one copy
of sesman could run on on address, as standard TCP listening rules
enforced this. This isn't the case with Unix Domain sockets. This
module implements a locking mechanism for a UDS which emulates the
standard TCP socket behaviour.
Daniel Richard G