PURPOSE: this strategy is atomic, and attempts to preserve file modes
NOTE: there is no preserve flag to FileUtils.mv, and we want to preserve the dst file
modes rather than the src file modes (preserve = true is what mv does already, we would like preserve = false which is tricky).
# File lib/chef/file_content_management/deploy/mv_unix.rb, line 30 def create(file) # this is very simple, but it ensures that ownership and file modes take # good defaults, in particular mode needs to obey umask on create Chef::Log.debug("touching #{file} to create it") FileUtils.touch(file) end
# File lib/chef/file_content_management/deploy/mv_unix.rb, line 37 def deploy(src, dst) # we are only responsible for content so restore the dst files perms Chef::Log.debug("reading modes from #{dst} file") stat = ::File.stat(dst) mode = stat.mode & 07777 uid = stat.uid gid = stat.gid Chef::Log.debug("applying mode = #{mode.to_s(8)}, uid = #{uid}, gid = #{gid} to #{src}") # i own the inode, so should be able to at least chmod it ::File.chmod(mode, src) # we may be running as non-root in which case because we are doing an mv we cannot preserve # the file modes. after the mv we have a different inode and if we don't have rights to # chown/chgrp on the inode then we can't fix the ownership. # # in the case where i'm running chef-solo on my homedir as myself and some root-shell # work has caused dotfiles of mine to change to root-owned, i'm fine with this not being # exceptional, and i think most use cases will consider this to not be exceptional, and # the right thing is to fix the ownership of the file to the user running the commmand # (which requires write perms to the directory, or mv will throw an exception) begin ::File.chown(uid, nil, src) rescue Errno::EPERM Chef::Log.warn("Could not set uid = #{uid} on #{src}, file modes not preserved") end begin ::File.chown(nil, gid, src) rescue Errno::EPERM Chef::Log.warn("Could not set gid = #{gid} on #{src}, file modes not preserved") end Chef::Log.debug("moving temporary file #{src} into place at #{dst}") FileUtils.mv(src, dst) end
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