search for: get_nr_list_exports

This is a subset of my v2 posting, but limited to just the NBD_OPT_LIST handling. The biggest change since v2 is the addition of added unit testing in all four language bindings (C, python, ocaml, golang). The tests require nbdkit built from git on PATH, and may not be entirely idiomatic, but I at least validated that they catch issues (for example, adding an exit statement near the end of the

...l exports that it supports. This can only be used if L<nbd_set_opt_mode(3)> enabled option mode. -In this mode, during connection we query the server for the list -of NBD exports and collect them in the handle. You can query -the list of exports provided by the server by calling -L<nbd_get_nr_list_exports(3)> and L<nbd_get_list_export_name(3)>. -After choosing the export you want, set the export name -(L<nbd_set_export_name(3)>), then finish connecting with L<nbd_opt_go(3)>. +The <list> function is called once per advertised export, with any +C<user_data> passed to t...

Proposal for new APIs to list exports. The general shape of the API can probably best be seen from the examples/list-exports.c example. Rich.

...peration can fail normally, so + * we need to check the return value and + * error code. + */ + r = nbd_connect_unix (nbd, argv[1]); + if (r == -1 && nbd_get_errno () == ENOTSUP) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + + if (nbd_get_nr_list_exports (nbd) == 0) { + fprintf (stderr, "Server does not support " + "listing exports.\n"); + exit (EXIT_FAILURE); + } + + /* Display the list of exports. */ + for (i = 0; + i < nbd_get_nr_list_exports (nbd); + i++) { + name = nbd_get_list_export_...

...l exports that it supports. This can only be used if L<nbd_set_opt_mode(3)> enabled option mode. -In this mode, during connection we query the server for the list -of NBD exports and collect them in the handle. You can query -the list of exports provided by the server by calling -L<nbd_get_nr_list_exports(3)> and L<nbd_get_list_export_name(3)>. -After choosing the export you want, set the export name -(L<nbd_set_export_name(3)>), then finish connecting with L<nbd_opt_go(3)>. +The <list> function is called once per advertised export, with any +C<user_data> passed to t...

...to check the return value and > + * error code. > + */ > + r = nbd_connect_unix (nbd, argv[1]); > + if (r == -1 && nbd_get_errno () == ENOTSUP) { > + fprintf (stderr, "%s\n", nbd_get_error ()); > + exit (EXIT_FAILURE); > + } > + > + if (nbd_get_nr_list_exports (nbd) == 0) { > + fprintf (stderr, "Server does not support " > + "listing exports.\n"); > + exit (EXIT_FAILURE); > + } > + > + /* Display the list of exports. */ > + for (i = 0; > + i < nbd_get_nr_list_exports (nbd); > +...

This rounds up the remaining bugs that I originally identified in: https://www.redhat.com/archives/libguestfs/2020-July/msg00153.html Eric Blake (4): api: Permit export list APIs when Connected info: Support --list with serializing servers info: Fix --json output when list size != 1 info: Permit --size --json generator/API.ml | 6 +++--- info/info-list-json.sh | 9 +++++++++

...to end +the connection without finishing negotiation."; + example = Some "examples/list-exports.c"; + see_also = [Link "get_opt_mode"; Link "opt_go"; Link "opt_abort"; + Link "get_list_exports"; + Link "get_nr_list_exports"; Link "get_list_export_name"]; + }; + + "get_opt_mode", { + default_call with + args = []; ret = RBool; + may_set_error = false; + shortdesc = "return whether option mode was enabled"; + longdesc = "\ +Return true if option negotiation mode...

An incremental improvement on top of listing exports. I still think it's worth experimenting with revisiting how our API for list mode should actually work [1] (so that we can reuse a single connection for both grabbing the list and finally using NBD_OPT_GO), but this change was easier to whip together while still thinking about that. [1]

Necessary when writing a client that wants to avoid unnecessary EINVAL errors from sending unaligned requests. At some point, we may want to add synchronous convenience API wrappers that do request splitting or read-modify-write to obey server constraints while still appearing to the library client as accepting any possible request. But such a wrapper should only be synchronous and not copied to

Well, I'm not quite done (I still want to get nbdinfo to work on a single nbd connection for all cases when reading the heads of the file is not required), but I'm happy with patches 1-11, and 12-13 show where I'm headed for getting NBD_OPT_INFO to work. Posting now to see if some of the earlier patches are ready to commit while I continue working on the latter half. Eric Blake (13):