Re: [Libvir] PATCH: 10/16: general purpose helper APIs

This patch provides a couple of helper APIs used by the forthcoming driver backends. - virStorageBackendUpdateVolInfo - take a filename and virStorageVolPtr and update the capacity/allocation information based on the file stat() results. Also update the permissions data on owner/mode and SELinux label. - virStorageBackendUpdateVolInfoFD - same as above but with a pre-opened filehandle - virStorageBackendStablePath - given a /dev/XXX node, and a directory of symlinks (eg /dev/disk/by-path), attempts to find a symlink pointing to the desired file. - virStorageBackendRunProgRegex - given one or more regexes and a command line argv[], execute the program and attempt to match its STDOUT against the regex. When complete matches are found invoke a callback. - virStorageBackendRunProgNul - given a command line argv[] and an expected number of fields per record, tokenize the STDOUT into records splitting on NULL, and invoke the callback per record. The SELinux code is optional, and can be replaced with calls to any other library which can provide MAC file labels, or just disabled completely..