Make config_write more atomic to prevent truncation when out of space

This is modeled after glib's g_file_set_contents. It doesn't use that
function directly because the writing is done with GIOChannel
streaming-like writes and g_file_set_contents expects the whole thing to
be in-memory.

Main differences with g_file_set_contents:

- complete lack of win32 special casing (cygwin/WSL should work though)
- no fallocate() (linux only, but we don't know the size upfront, anyway)
- always calls fsync (glib skips it on btrfs or when not overwriting)

Other than that, it's the same old mkstemp + fsync + rename.

0 files changed, 0 insertions, 0 deletions