search for: nbd_connect_tcp

When we make a TCP connection we have to make multiple underlying connect(2) calls, once for each address returned by getaddrinfo. Unfortunately this meant that we lost the errno from any of these calls: $ nbdsh -c 'h.connect_tcp ("localhost", "nbd")' nbd.Error: nbd_connect_tcp: connect: localhost:nbd: could not connect to remote host This commit saves the errno from the first failed connect(2): $ ./run nbdsh -c 'h.connect_tcp ("localhost", "nbd")' nbd.Error: nbd_connect_tcp: connect: localhost:nbd: could not connect to remote host: Connectio...

On 5/22/19 4:50 AM, Richard W.M. Jones wrote: > If not using multi-conn then obviously the synchronous connection > calls ‘nbd_connect_unix’, ‘nbd_connect_tcp’ and ‘nbd_connect_command’ > should only return when the (one) connection object is connected. > > In the multi-conn case it's not very clear what these synchronous > calls should do. Previously I had it so that they would return as > soon as at least one connection was connect...

nbd_connect_unix|tcp had a tricky failure case. This is a consequence of allowing callers to mix synchronous and asynchronous calls, with multi-conn thrown into the mix. I think the new behaviour proposed here is better. We could do with a better way of classifying the state of connections, such as are they connectING. Rich.

On 5/21/19 3:44 PM, Richard W.M. Jones wrote: > If not using multi-conn then obviously the synchronous connection > calls ‘nbd_connect_unix’, ‘nbd_connect_tcp’ and ‘nbd_connect_command’ > should only return when the (one) connection object is connected. > > In the multi-conn case it's not very clear what these synchronous > calls should do. Previously I had it so that they would return as > soon as at least one connection was connect...

Rich recently patched things to generate one man page per function rather than libnbd-api.3 (nice), but in doing so got stumped by a problem with a fresh git clone (automake fails for any 'include' directive that does not already exist). I've figured out how to hack around it, but the hack requires GNU make. We already use GNU make constructs elsewhere (such as $(wildcard)), but

...pid = -1; + int retry; #endif int64_t actual_size; char buf[512]; @@ -114,14 +116,19 @@ main (int argc, char *argv[]) } /* Unfortunately there's no good way to wait for qemu-nbd to start - * serving, so ... + * serving, so we need to retry here. */ - sleep (5); - - if (nbd_connect_tcp (nbd, "localhost", port_str) == -1) { - fprintf (stderr, "%s\n", nbd_get_error ()); - goto out; + for (retry = 0; retry < 5; ++retry) { + sleep (1 << retry); + if (nbd_connect_tcp (nbd, "localhost", port_str) == -1) { + fprintf (stderr, &quot...

On Tue, May 21, 2019 at 05:08:05PM -0500, Eric Blake wrote: > On 5/21/19 3:44 PM, Richard W.M. Jones wrote: > > If not using multi-conn then obviously the synchronous connection > > calls ‘nbd_connect_unix’, ‘nbd_connect_tcp’ and ‘nbd_connect_command’ > > should only return when the (one) connection object is connected. > > > > In the multi-conn case it's not very clear what these synchronous > > calls should do. Previously I had it so that they would return as > > soon as at least o...

If not using multi-conn then obviously the synchronous connection calls ‘nbd_connect_unix’, ‘nbd_connect_tcp’ and ‘nbd_connect_command’ should only return when the (one) connection object is connected. In the multi-conn case it's not very clear what these synchronous calls should do. Previously I had it so that they would return as soon as at least one connection was connected. However this is a pr...

If not using multi-conn then obviously the synchronous connection calls ‘nbd_connect_unix’, ‘nbd_connect_tcp’ and ‘nbd_connect_command’ should only return when the (one) connection object is connected. In the multi-conn case it's not very clear what these synchronous calls should do. Previously I had it so that they would return as soon as at least one connection was connected. However this is a pr...

Patch 1/6 was posted before and I didn't change it: https://www.redhat.com/archives/libguestfs/2019-May/thread.html#00134 That doesn't necessarily mean I shouldn't change it, I'm posting it again because the other patches depend on it. The main change in this series is we add three new API functions: nbd_aio_is_created - connection has just been created

One API change, some small documentation changes.

...nbdkit_debug ("permanent failure while talking to server %s: %m", - sockname); + servname); h->dead = true; } else if (!err) @@ -861,6 +901,45 @@ nbd_connect_unix(struct handle *h) return 0; } +/* Connect to a TCP socket */ +static int +nbd_connect_tcp(struct handle *h) +{ + struct addrinfo hints = { .ai_family = AF_UNSPEC, + .ai_socktype = SOCK_STREAM, }; + struct addrinfo *result, *rp; + int r; + const int optval = 1; + + nbdkit_debug ("connecting to TCP socket host=%s port=%s", hostname, port); + r =...

...se/nbdfuse.pod @@ -19,6 +19,8 @@ Other modes: nbdfuse MOUNTPOINT[/FILENAME] --unix SOCKET + nbdfuse MOUNTPOINT[/FILENAME] --vsock CID PORT + =head1 DESCRIPTION nbdfuse presents a Network Block Device as a local file inside a FUSE @@ -230,6 +232,11 @@ unencrypted TCP socket. See also L<nbd_connect_tcp(3)>. Select Unix mode. Connect to an NBD server on a Unix domain socket. See also L<nbd_connect_unix(3)>. +=item B<--vsock> CID PORT + +Select vsock mode. Connect to an NBD server on a C<AF_VSOCK> socket. +See also L<nbd_connect_vsock(3)>. + =back =head1 NOTES @...

...gv[1]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + else if (nbd_connect_unix (nbd, argv[1]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + else { + if (nbd_connect_tcp (nbd, argv[1], argv[2]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + + exportsize = nbd_get_size (nbd); + if (exportsize == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + + if (n...

--- docs/libnbd.pod | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/docs/libnbd.pod b/docs/libnbd.pod index b909833..f299ef1 100644 --- a/docs/libnbd.pod +++ b/docs/libnbd.pod @@ -228,6 +228,8 @@ For C<nbd_connect_tcp> the third parameter is the port name or number, which can either be a name from F</etc/services> or the port number as a string (eg. C<"10809">). +=head2 Connecting to a subprocess + Some NBD servers — notably L<nbdkit(1)> with the C<-s> parameter — can a...

I got annoyed by qemu-nbd's default of only allowing a single connection; combine that with nbdkit's nbd plugin, and even 'qemu-nbd --list' of nbdkit counts as the single connection and immediately hangs up. If we introduce a shared mode, then 'qemu-nbd --list' can connect as many times as it wants without killing the original qemu-nbd wrapped by nbdkit. But this in turn

...nnect to the server. + +This function may be called regardless of whether TLS is +supported, but will have no effect unless C<nbd_set_tls> +is also used to request or require TLS."; }; (* Can't implement this because we need a way to return string that @@ -1112,7 +1130,9 @@ C<nbd_connect_tcp> or C<nbd_connect_unix>. This call returns when the connection has been made. This call will fail if libnbd was not compiled with libxml2; you can -test whether this is the case with C<nbd_supports_uri>."; +test whether this is the case with C<nbd_supports_uri>. Suppo...

...gv[1]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + else if (nbd_connect_unix (nbd, argv[1]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + else { + if (nbd_connect_tcp (nbd, argv[1], argv[2]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + + exportsize = nbd_get_size (nbd); + if (exportsize == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + + if (n...

...ared here 954 | int fd; | ^~ cc1: all warnings being treated as errors --- plugins/nbd/nbd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/plugins/nbd/nbd.c b/plugins/nbd/nbd.c index dba46f1..4d0a67c 100644 --- a/plugins/nbd/nbd.c +++ b/plugins/nbd/nbd.c @@ -960,6 +960,8 @@ nbd_connect_tcp (void) return -1; } + assert (result != NULL); + for (rp = result; rp; rp = rp->ai_next) { fd = socket (rp->ai_family, rp->ai_socktype, rp->ai_protocol); if (fd == -1) -- 2.21.0

Accepting only Unix sockets can be a bit limiting; let's be more flexible. Eric Blake (2): nbd: Refactor Unix socket connection nbd: Support TCP socket plugins/nbd/nbdkit-nbd-plugin.pod | 36 ++++-- plugins/nbd/nbd.c | 175 ++++++++++++++++++++++-------- TODO | 3 - 3 files changed, 161 insertions(+), 53 deletions(-) -- 2.20.1