I have hit a problem with perfused(8) developement. This daemon talks with FUSE filesystems over a socket, currently of SOCK_STREAM type. Every time the kernel issue a filesystem operation, perfused(8) will produce a frame containing a FUSE operation and send it over the socket. On the FUSE filesystem end, read() is used to read frames, using a huge length parameter. If perfused sends frames faster than the filesystem consumes them, then multiple frames will be readen at once, and the filesystem will discard anything beyond the first one. Discarded frames get no reply at all, producing a hang in the process that caused the file operation. Does the frame have a fixed-length (more or less) part at the beginning that has a length in it? It seems obvious that it should, and that the way to read on a stream-type socket is to do multiple reads with the size of the header - bytes read so far until the header is read, and then calculate the data size, and then loop reading data_size - data_bytes_read until all data is read, and then continue.
Description: PGP signature