[Qemu-devel] [RFC PATCH 11/13] hmp: add NBD server commands

[Paolo Bonzini]

At the HMP level there is no nbd_server_add command.  nbd_server_start
automatically exposes all of the VM's block devices, and an option -w
makes them writable.

Signed-off-by: Paolo Bonzini <address@hidden>
---
 hmp-commands.hx | 29 +++++++++++++++++++++++++
 hmp.c           | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 hmp.h           |  2 ++
 3 file modificati, 97 inserzioni(+)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index f6104b0..cabb886 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1248,6 +1248,35 @@ Remove all matches from the access control list, and set 
the default
 policy back to @code{deny}.
 ETEXI
 
+    {
+        .name       = "nbd_server_start",
+        .args_type  = "writable:-w,uri:s",
+        .params     = "nbd_server_start [-w] host:port",
+        .help       = "serve block devices on the given host and port",
+        .mhandler.cmd = hmp_nbd_server_start,
+    },
+STEXI
address@hidden nbd_server_start @var{host}:@var{port}
address@hidden nbd_server_start
+Start an NBD server on the given host and/or port, and serve all of the
+virtual machine's block devices that have an inserted media on it.
+The @option{-w} option makes the devices writable.
+ETEXI
+
+    {
+        .name       = "nbd_server_stop",
+        .args_type  = "",
+        .params     = "nbd_server_stop",
+        .help       = "stop serving block devices using the NBD protocol",
+        .mhandler.cmd = hmp_nbd_server_stop,
+    },
+STEXI
address@hidden nbd_server_stop
address@hidden nbd_server_stop
+Stop the QEMU embedded NBD server.
+ETEXI
+
+
 #if defined(TARGET_I386)
 
     {
diff --git a/hmp.c b/hmp.c
index a9d5675..10ff50d 100644
--- a/hmp.c
+++ b/hmp.c
@@ -18,6 +18,7 @@
 #include "qemu-option.h"
 #include "qemu-timer.h"
 #include "qmp-commands.h"
+#include "qemu_socket.h"
 #include "monitor.h"
 
 static void hmp_handle_error(Monitor *mon, Error **errp)
@@ -1102,3 +1103,68 @@ void hmp_closefd(Monitor *mon, const QDict *qdict)
     qmp_closefd(fdname, &errp);
     hmp_handle_error(mon, &errp);
 }
+
+void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
+{
+    const char *uri = qdict_get_str(qdict, "uri");
+    int writable = qdict_get_try_bool(qdict, "writable", 0);
+    Error *errp = NULL;
+    QemuOpts *opts;
+    BlockDriverState *bs;
+    IPSocketAddress addr;
+
+    /* First check if the address is available and start the server.  */
+    opts = qemu_opts_create(&socket_opts, NULL, 0, NULL);
+    if (inet_parse(opts, uri) != 0) {
+        error_set(&errp, QERR_SOCKET_CREATE_FAILED);
+       goto exit;
+    }
+
+    memset(&addr, 0, sizeof(addr));
+    addr.host = (char *) qemu_opt_get(opts, "host");
+    addr.port = (char *) qemu_opt_get(opts, "port");
+    addr.ipv4 = qemu_opt_get_bool(opts, "ipv4", 0);
+    addr.ipv6 = qemu_opt_get_bool(opts, "ipv6", 0);
+    addr.has_ipv4 = addr.has_ipv6 = true;
+
+    if (addr.host == NULL || addr.port == NULL) {
+        error_set(&errp, QERR_SOCKET_CREATE_FAILED);
+        goto exit;
+    }
+
+    qmp_nbd_server_start(&addr, &errp);
+    if (errp != NULL) {
+        goto exit;
+    }
+
+    /* Then try adding all block devices.  If one fails, close all and
+     * exit.
+     */
+    bs = NULL;
+    while ((bs = bdrv_next(bs))) {
+        if (!bdrv_is_inserted(bs)) {
+            continue;
+        }
+
+        qmp_nbd_server_add(bdrv_get_device_name(bs),
+                           true, !bdrv_is_read_only(bs) && writable,
+                           &errp);
+
+        if (errp != NULL) {
+            qmp_nbd_server_stop(NULL);
+            break;
+        }
+    }
+
+exit:
+    qemu_opts_del(opts);
+    hmp_handle_error(mon, &errp);
+}
+
+void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict)
+{
+    Error *errp = NULL;
+
+    qmp_nbd_server_stop(&errp);
+    hmp_handle_error(mon, &errp);
+}
diff --git a/hmp.h b/hmp.h
index 7dd93bf..89d3960 100644
--- a/hmp.h
+++ b/hmp.h
@@ -71,5 +71,7 @@ void hmp_netdev_add(Monitor *mon, const QDict *qdict);
 void hmp_netdev_del(Monitor *mon, const QDict *qdict);
 void hmp_getfd(Monitor *mon, const QDict *qdict);
 void hmp_closefd(Monitor *mon, const QDict *qdict);
+void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
+void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
 
 #endif
-- 
1.7.11.2