On Wed, Aug 23, 2023 at 05:34:07PM +0200, David Hildenbrand wrote: > open() does not fail on directories when opening them readonly (O_RDONLY). > > Currently, we succeed opening such directories and fail later during > mmap(), resulting in a misleading error message. > > $ ./qemu-system-x86_64 \ > -object memory-backend-file,id=ram0,mem-path=tmp,readonly=true,size=1g > qemu-system-x86_64: unable to map backing store for guest RAM: No such device > > To identify directories and handle them accordingly in file_ram_open() > also when readonly=true was specified, detect if we just opened a directory > using fstat() instead. Then, fail file_ram_open() right away, similarly > to how we now fail if the file does not exist and we want to open the > file readonly. > > With this change, we get a nicer error message: > qemu-system-x86_64: can't open backing store tmp for guest RAM: Is a > directory > > Note that the only memory-backend-file will end up calling > memory_region_init_ram_from_file() -> qemu_ram_alloc_from_file() -> > file_ram_open(). > > Reported-by: Thiner Logoer <logoerthin...@163.com> > Signed-off-by: David Hildenbrand <da...@redhat.com>
Reviewed-by: Peter Xu <pet...@redhat.com> -- Peter Xu