Inter-domain file copying

Remote procedure calls (qrexec and Qubes RPC) are used for inter-domain file copying. There are two cases when we need a mechanism to copy files between VMs: ‘Regular’ file copy, when a user instructs a file manager to copy some given files/directories to a different VM. DispVM copy, when a user selects ‘Open in DispVM’ on a file; this file must be copied to a disposable VM, edited by the user and, possibly, a modified file must be copied back from DispVM to the VM.