Re: [Libguestfs] [nbdkit PATCH] nbd: Add new nbd forwarding plugin

This is a minimal implementation of an NBD forwarder; it lets us convert between old and newstyle connections (great if a client expects one style but the real server only provides the other), or add TLS safety on top of a server without having to rewrite that server. Right now, the real server is expected to live on a named Unix socket, and the transactions are serialized rather than interleaved; further enhancements could be made to also permit TCP servers or more efficient transmission.

+/* Read an entire buffer, returning 0 on success or -1 with errno set */ +static int read_full (int fd, void *buf, size_t len) +{ + ssize_t r; + + while (len) { + r = read (fd, buf, len); + if (r < 0) { + if (errno == EINTR || errno == EAGAIN) + continue; + return -1;