361 lines
12 KiB
Diff
361 lines
12 KiB
Diff
From 0095b003b56894baad8e6789d523cf3c51905c05 Mon Sep 17 00:00:00 2001
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From: "Richard W.M. Jones" <rjones@redhat.com>
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Date: Tue, 17 May 2016 19:43:16 +0100
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Subject: [PATCH 10/10] Implement newstyle export names.
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This is now required by qemu >= 2.6. See this lengthy qemu-devel
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thread for details:
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https://lists.nongnu.org/archive/html/qemu-devel/2016-05/threads.html#02752
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---
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TODO | 13 -------------
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docs/nbdkit.pod | 52 ++++++++++++++++++++++++++++++++-------------------
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src/connections.c | 49 ++++++++++++++++++++++++++++++++++++++++--------
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src/internal.h | 1 +
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src/main.c | 32 +++++++++++++++++++++++--------
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src/protocol.h | 3 +--
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tests/test-newstyle.c | 7 +++++--
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7 files changed, 105 insertions(+), 52 deletions(-)
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diff --git a/TODO b/TODO
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index 177a07c..30bf72e 100644
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--- a/TODO
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+++ b/TODO
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@@ -11,19 +11,6 @@
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* Performance - measure and improve it.
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-* Implement export names. With export names it should be possible to
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- have multiple plugins on the command line (each responding to a
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- different export of course):
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-
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- nbdkit --export /foo plugin.so --export /bar another-plugin.so
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-
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- Note it should also be possible to either elect one plugin as the
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- default that accepts all exportnames, or to divide the export name
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- "space" up using regexps or wildcards.
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-
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- Export names are not actually paths (although that is how they are
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- often used), but arbitrary UTF-8 text strings.
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-
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* Implement true parallel request handling. Currently
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NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS and
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NBDKIT_THREAD_MODEL_PARALLEL are the same, because we handle
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diff --git a/docs/nbdkit.pod b/docs/nbdkit.pod
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index 7204a38..728aad3 100644
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--- a/docs/nbdkit.pod
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+++ b/docs/nbdkit.pod
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@@ -6,7 +6,7 @@ nbdkit - A toolkit for creating NBD servers
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=head1 SYNOPSIS
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- nbdkit [--dump-config] [-f] [-g GROUP] [-i IPADDR]
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+ nbdkit [--dump-config] [-e EXPORTNAME] [-f] [-g GROUP] [-i IPADDR]
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[--newstyle] [--oldstyle] [-P PIDFILE] [-p PORT] [-r]
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[--run CMD] [-s] [-U SOCKET] [-u USER] [-v] [-V]
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PLUGIN [key=value [key=value [...]]]
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@@ -74,6 +74,19 @@ Display brief command line usage information and exit.
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Dump out the compile-time configuration values and exit.
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+=item B<-e> EXPORTNAME
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+
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+=item B<--export> EXPORTNAME
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+
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+=item B<--export-name> EXPORTNAME
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+
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+=item B<--exportname> EXPORTNAME
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+
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+Set the exportname and use the newstyle protocol (implies I<-n>).
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+
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+If not set, exportname C<""> (empty string) is used. Exportnames are
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+not allowed with the oldstyle protocol.
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+
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=item B<-f>
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=item B<--foreground>
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@@ -118,9 +131,10 @@ protocol. See L</NEW STYLE VS OLD STYLE PROTOCOL> below.
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=item B<--oldstyle>
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-Use the oldstyle NBD protocol. This is currently the default, so this
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-flag does nothing, but it is possible we might change the default
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-protocol in future. See L</NEW STYLE VS OLD STYLE PROTOCOL> below.
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+Use the oldstyle NBD protocol. This is currently the default (unless
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+you use I<-n> or I<-e>), so this flag does nothing, but it is possible
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+we might change the default protocol in future. See L</NEW STYLE VS
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+OLD STYLE PROTOCOL> below.
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=item B<-P> PIDFILE
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@@ -307,27 +321,29 @@ use depends on the client and cannot be known in advance, nor can it
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be negotiated from the server side.
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nbdkit currently defaults to the oldstyle protocol for compatibility
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-with qemu and libguestfs. This is also the same behaviour as
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-qemu-nbd. Use the I<-n> or I<--newstyle> flag on the command line to
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-use the newstyle protocol. Use the I<-o> or I<--oldstyle> flag to
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-force the oldstyle protocol.
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+with qemu and libguestfs. This is also the same behaviour as qemu-nbd
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+E<le> 2.5. Use the I<-n> or I<--newstyle> flag on the command line to
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+use the newstyle protocol. Use the I<-e> or I<--exportname> flag to
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+set the exportname for the newstyle protocol. Use the I<-o> or
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+I<--oldstyle> flag to force the oldstyle protocol.
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Some common clients and the protocol they require:
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- Client Protocol
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+ Client Protocol
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------------------------------------------------------------
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- qemu without exportname oldstyle
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- qemu with exportname newstyle
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- nbd-client < 3.10 client can talk either protocol
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- nbd-client >= 3.10 newstyle
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+ qemu <= 2.5 without exportname oldstyle
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+ qemu <= 2.5 with exportname newstyle
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+ qemu >= 2.6 client can talk either protocol
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+ nbd-client < 3.10 client can talk either protocol
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+ nbd-client >= 3.10 newstyle
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-If you use qemu without the exportname field against a newstyle
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-server, it will give the error:
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+If you use qemu E<le> 2.5 without the exportname field against a
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+newstyle server, it will give the error:
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Server requires an export name
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-If you use qemu with the exportname field against an oldstyle server,
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-it will give the error:
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+If you use qemu E<le> 2.5 with the exportname field against an
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+oldstyle server, it will give the error:
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Server does not support export names
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@@ -341,8 +357,6 @@ document says should be the case (which isn't based in reality), then
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you should always use newstyle when using port 10809, and use oldstyle
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on all other ports.
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-nbdkit ignores export names at present (see also the C<TODO> file).
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-
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=head1 SIGNALS
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C<nbdkit> responds to the following signals:
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diff --git a/src/connections.c b/src/connections.c
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index 34566b3..0c93f35 100644
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--- a/src/connections.c
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+++ b/src/connections.c
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@@ -222,13 +222,8 @@ _negotiate_handshake_oldstyle (struct connection *conn)
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return 0;
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}
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-/* Receive newstyle options.
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- *
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- * Currently we ignore NBD_OPT_EXPORT_NAME (see TODO), we close the
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- * connection if sent NBD_OPT_ABORT, we send a canned list of
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- * options for NBD_OPT_LIST, and we send NBD_REP_ERR_UNSUP for
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- * everything else.
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- */
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+/* Receive newstyle options. */
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+
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static int
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send_newstyle_option_reply (struct connection *conn,
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uint32_t option, uint32_t reply)
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@@ -250,6 +245,39 @@ send_newstyle_option_reply (struct connection *conn,
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}
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static int
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+send_newstyle_option_reply_exportname (struct connection *conn,
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+ uint32_t option, uint32_t reply,
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+ const char *exportname)
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+{
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+ struct fixed_new_option_reply fixed_new_option_reply;
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+ size_t name_len = strlen (exportname);
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+ uint32_t len;
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+
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+ fixed_new_option_reply.magic = htobe64 (NBD_REP_MAGIC);
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+ fixed_new_option_reply.option = htobe32 (option);
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+ fixed_new_option_reply.reply = htobe32 (reply);
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+ fixed_new_option_reply.replylen = htobe32 (name_len + sizeof (len));
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+
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+ if (xwrite (conn->sockout,
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+ &fixed_new_option_reply, sizeof fixed_new_option_reply) == -1) {
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+ nbdkit_error ("write: %m");
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+ return -1;
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+ }
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+
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+ len = htobe32 (name_len);
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+ if (xwrite (conn->sockout, &len, sizeof len) == -1) {
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+ nbdkit_error ("write: %m");
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+ return -1;
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+ }
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+ if (xwrite (conn->sockout, exportname, name_len) == -1) {
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+ nbdkit_error ("write: %m");
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+ return -1;
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+ }
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+
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+ return 0;
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+}
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+
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+static int
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_negotiate_handshake_newstyle_options (struct connection *conn)
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{
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struct new_option new_option;
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@@ -309,7 +337,12 @@ _negotiate_handshake_newstyle_options (struct connection *conn)
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continue;
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}
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- /* Since we don't support export names, there is nothing to list. */
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+ /* Send back the exportname. */
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+ debug ("newstyle negotiation: advertising export '%s'", exportname);
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+ if (send_newstyle_option_reply_exportname (conn, option, NBD_REP_SERVER,
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+ exportname) == -1)
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+ return -1;
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+
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if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
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return -1;
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break;
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diff --git a/src/internal.h b/src/internal.h
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index 0603779..f58086a 100644
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--- a/src/internal.h
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+++ b/src/internal.h
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@@ -48,6 +48,7 @@
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#endif
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/* main.c */
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+extern const char *exportname;
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extern const char *ipaddr;
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extern int newstyle;
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extern const char *port;
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diff --git a/src/main.c b/src/main.c
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index db4361e..9529f19 100644
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--- a/src/main.c
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+++ b/src/main.c
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@@ -65,6 +65,7 @@ static void fork_into_background (void);
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static uid_t parseuser (const char *);
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static gid_t parsegroup (const char *);
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+const char *exportname; /* -e */
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int foreground; /* -f */
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const char *ipaddr; /* -i */
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int newstyle; /* -n */
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@@ -84,10 +85,13 @@ static char *random_fifo = NULL;
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enum { HELP_OPTION = CHAR_MAX + 1 };
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-static const char *short_options = "fg:i:nop:P:rsu:U:vV";
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+static const char *short_options = "e:fg:i:nop:P:rsu:U:vV";
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static const struct option long_options[] = {
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{ "help", 0, NULL, HELP_OPTION },
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{ "dump-config",0, NULL, 0 },
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+ { "export", 1, NULL, 'e' },
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+ { "export-name",1, NULL, 'e' },
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+ { "exportname", 1, NULL, 'e' },
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{ "foreground", 0, NULL, 'f' },
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{ "no-fork", 0, NULL, 'f' },
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{ "group", 1, NULL, 'g' },
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@@ -115,7 +119,7 @@ static const struct option long_options[] = {
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static void
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usage (void)
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{
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- printf ("nbdkit [--dump-config] [-f] [-g GROUP] [-i IPADDR]\n"
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+ printf ("nbdkit [--dump-config] [-e EXPORTNAME] [-f] [-g GROUP] [-i IPADDR]\n"
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" [--newstyle] [--oldstyle] [-P PIDFILE] [-p PORT] [-r]\n"
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" [--run CMD] [-s] [-U SOCKET] [-u USER] [-v] [-V]\n"
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" PLUGIN [key=value [key=value [...]]]\n"
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@@ -173,6 +177,11 @@ main (int argc, char *argv[])
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}
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break;
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+ case 'e':
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+ exportname = optarg;
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+ newstyle = 1;
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+ break;
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+
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case 'f':
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foreground = 1;
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break;
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@@ -190,9 +199,6 @@ main (int argc, char *argv[])
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break;
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case 'o':
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- /* XXX When we add support for exportnames, we will need to
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- * ensure that the user does not use -o + --export.
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- */
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newstyle = 0;
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break;
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@@ -263,12 +269,22 @@ main (int argc, char *argv[])
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exit (EXIT_FAILURE);
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}
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+ /* Oldstyle protocol + exportname not allowed. */
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+ if (newstyle == 0 && exportname != NULL) {
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+ fprintf (stderr,
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+ "%s: cannot use oldstyle protocol (-o) and exportname (-e)\n",
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+ program_name);
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+ exit (EXIT_FAILURE);
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+ }
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+
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+ /* If exportname was not set on the command line, use "". */
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+ if (exportname == NULL)
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+ exportname = "";
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+
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/* Remaining command line arguments define the plugins and plugin
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* configuration. If --help or --version was specified, we still
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* partially parse these in order that we can display the per-plugin
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- * help/version information. In future (when the new protocol and
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- * export names are permitted) we will allow multiple plugins to be
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- * given, but at the moment only one plugin is allowed.
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+ * help/version information.
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*/
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while (optind < argc) {
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const char *filename = argv[optind];
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diff --git a/src/protocol.h b/src/protocol.h
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index 71a8098..c885d9e 100644
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--- a/src/protocol.h
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+++ b/src/protocol.h
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@@ -70,8 +70,7 @@ struct fixed_new_option_reply {
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uint64_t magic; /* NBD_REP_MAGIC, network byte order */
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uint32_t option; /* option we are replying to */
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uint32_t reply; /* NBD_REP_* */
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- uint32_t replylen; /* we always send zero at the moment */
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- /* reply data follows, but we currently never send any */
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+ uint32_t replylen;
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} __attribute__((packed));
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#define NBD_REP_MAGIC UINT64_C(0x3e889045565a9)
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diff --git a/tests/test-newstyle.c b/tests/test-newstyle.c
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index b1d8ce7..adcc568 100644
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--- a/tests/test-newstyle.c
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+++ b/tests/test-newstyle.c
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@@ -44,6 +44,8 @@
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#include "test.h"
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+#define EXPORTNAME "/"
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+
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int
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main (int argc, char *argv[])
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{
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@@ -52,7 +54,8 @@ main (int argc, char *argv[])
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char *data;
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size_t i, size;
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- if (test_start_nbdkit ("-n", NBDKIT_PLUGIN ("file"), "file=file-data",
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+ if (test_start_nbdkit ("-e", EXPORTNAME,
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+ "-n", NBDKIT_PLUGIN ("file"), "file=file-data",
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NULL) == -1)
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exit (EXIT_FAILURE);
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@@ -63,7 +66,7 @@ main (int argc, char *argv[])
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}
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/* Using any exportname causes qemu to use the newstyle protocol. */
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- r = guestfs_add_drive_opts (g, "/" /* exportname */,
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+ r = guestfs_add_drive_opts (g, EXPORTNAME,
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GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
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GUESTFS_ADD_DRIVE_OPTS_PROTOCOL, "nbd",
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GUESTFS_ADD_DRIVE_OPTS_SERVER, server,
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--
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2.7.4
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