I am debugging a problem where MoinMoin on CentOS is throwing a permissions error, but I can't track down where the problematic file / directory is.

I ran strace -vp <pid> on the apache pid; when I have the problem I see this:

epoll_wait(10, {{EPOLLIN, {u32=3487534344, u64=140367313734920}}}, 2, 10000) = 1
accept4(6, {sa_family=AF_INET6, sin6_port=htons(52621), inet_pton
    (AF_INET6, "::ffff:105.193.30.91", &sin6_addr), sin6_flowinfo=0, 
    sin6_scope_id=0}, [28], SOCK_CLOEXEC) = 11
## Later on...
read(7, 0x7fffa658ad7f, 1)              = -1 EAGAIN (Resource temporarily 
    unavailable)

However, since apache is already running, I see no corresponding open() on the file referred to as 7; thus I see the permissions problem, but I still don't know which file is the problem.

I know I could try to catch all the file opens when I respawn apache, but I'm hoping there is a way to map file 7 to a real filename... is there a way to do this?