[PATCH v2 0/3] qapi/ui: add change-vnc-listen

[PATCH v2 0/3] qapi/ui: add change-vnc-listen

[Vladimir Sementsov-Ogievskiy]

Hi all!

v2:
01, 03: add Mark-Andre's r-bs
02: add a bit of documentation and "'if': 'CONFIG_VNC'", still, keep
    Mark-Adnre's r-b here too

Recently our customer requested a possibility to change VNC listen port
dynamically.

Happily in Rhel7-based Qemu we already have this possibility: through
deprecated "change" qmp command.

But since 6.0 "change" qmp command was removed, with recommendation to
use change-vnc-password or blockdev-change-medium instead. Of course,
neither of them allow change VNC listen port.

So, let's reimplement the possibility.

Note: now, reconnecting may trigger existing deadlock, as I described
in my message "Re: [PULL 09/11] ui/vnc: clipboard support":
 <973ddebe-14a9-4ba7-c389-7a97d6017237@virtuozzo.com>

Simple hack helps, but I'm not sure it's safe itself:

    diff --git a/ui/vnc.c b/ui/vnc.c
    index 69bbf3b6f6..8c6b378e2e 100644
    --- a/ui/vnc.c
    +++ b/ui/vnc.c
    @@ -1354,12 +1354,12 @@ void vnc_disconnect_finish(VncState *vs)
             /* last client gone */
             vnc_update_server_surface(vs->vd);
         }
    +    vnc_unlock_output(vs);
    +
         if (vs->cbpeer.update.notify) {
             qemu_clipboard_peer_unregister(&vs->cbpeer);
         }
     
    -    vnc_unlock_output(vs);
    -
         qemu_mutex_destroy(&vs->output_mutex);
         if (vs->bh != NULL) {
             qemu_bh_delete(vs->bh);


Vladimir Sementsov-Ogievskiy (3):
  ui/vnc: refactor arrays of addresses to SocketAddressList
  qapi/ui: introduce change-vnc-listen
  avocado/vnc: add test_change_listen

 docs/about/removed-features.rst |   3 +-
 qapi/ui.json                    |  19 ++++
 ui/vnc.c                        | 155 ++++++++++++++++----------------
 tests/avocado/vnc.py            |  10 +++
 4 files changed, 108 insertions(+), 79 deletions(-)

-- 
2.31.1

[PATCH v2 1/3] ui/vnc: refactor arrays of addresses to SocketAddressList

[Vladimir Sementsov-Ogievskiy]

Let's use SocketAddressList instead of dynamic arrays.
Benefits:
 - Automatic cleanup: don't need specific freeing function and drop
   some gotos.
 - Less indirection: no triple asterix anymore!
 - Prepare for the following commit, which will reuse new interface of
   vnc_display_listen().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 ui/vnc.c | 129 ++++++++++++++++++++++---------------------------------
 1 file changed, 51 insertions(+), 78 deletions(-)

diff --git a/ui/vnc.c b/ui/vnc.c
index 1ed1c7efc6..e8430531c0 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -3812,30 +3812,19 @@ static int vnc_display_get_address(const char *addrstr,
     return ret;
 }
 
-static void vnc_free_addresses(SocketAddress ***retsaddr,
-                               size_t *retnsaddr)
-{
-    size_t i;
-
-    for (i = 0; i < *retnsaddr; i++) {
-        qapi_free_SocketAddress((*retsaddr)[i]);
-    }
-    g_free(*retsaddr);
-
-    *retsaddr = NULL;
-    *retnsaddr = 0;
-}
-
 static int vnc_display_get_addresses(QemuOpts *opts,
                                      bool reverse,
-                                     SocketAddress ***retsaddr,
-                                     size_t *retnsaddr,
-                                     SocketAddress ***retwsaddr,
-                                     size_t *retnwsaddr,
+                                     SocketAddressList **saddr_list_ret,
+                                     SocketAddressList **wsaddr_list_ret,
                                      Error **errp)
 {
     SocketAddress *saddr = NULL;
     SocketAddress *wsaddr = NULL;
+    g_autoptr(SocketAddressList) saddr_list = NULL;
+    SocketAddressList **saddr_tail = &saddr_list;
+    SocketAddress *single_saddr = NULL;
+    g_autoptr(SocketAddressList) wsaddr_list = NULL;
+    SocketAddressList **wsaddr_tail = &wsaddr_list;
     QemuOptsIter addriter;
     const char *addr;
     int to = qemu_opt_get_number(opts, "to", 0);
@@ -3844,23 +3833,16 @@ static int vnc_display_get_addresses(QemuOpts *opts,
     bool ipv4 = qemu_opt_get_bool(opts, "ipv4", false);
     bool ipv6 = qemu_opt_get_bool(opts, "ipv6", false);
     int displaynum = -1;
-    int ret = -1;
-
-    *retsaddr = NULL;
-    *retnsaddr = 0;
-    *retwsaddr = NULL;
-    *retnwsaddr = 0;
 
     addr = qemu_opt_get(opts, "vnc");
     if (addr == NULL || g_str_equal(addr, "none")) {
-        ret = 0;
-        goto cleanup;
+        return 0;
     }
     if (qemu_opt_get(opts, "websocket") &&
         !qcrypto_hash_supports(QCRYPTO_HASH_ALG_SHA1)) {
         error_setg(errp,
                    "SHA1 hash support is required for websockets");
-        goto cleanup;
+        return -1;
     }
 
     qemu_opt_iter_init(&addriter, opts, "vnc");
@@ -3871,7 +3853,7 @@ static int vnc_display_get_addresses(QemuOpts *opts,
                                      ipv4, ipv6,
                                      &saddr, errp);
         if (rv < 0) {
-            goto cleanup;
+            return -1;
         }
         /* Historical compat - first listen address can be used
          * to set the default websocket port
@@ -3879,13 +3861,16 @@ static int vnc_display_get_addresses(QemuOpts *opts,
         if (displaynum == -1) {
             displaynum = rv;
         }
-        *retsaddr = g_renew(SocketAddress *, *retsaddr, *retnsaddr + 1);
-        (*retsaddr)[(*retnsaddr)++] = saddr;
+        QAPI_LIST_APPEND(saddr_tail, saddr);
     }
 
-    /* If we had multiple primary displays, we don't do defaults
-     * for websocket, and require explicit config instead. */
-    if (*retnsaddr > 1) {
+    if (saddr_list && !saddr_list->next) {
+        single_saddr = saddr_list->value;
+    } else {
+        /*
+         * If we had multiple primary displays, we don't do defaults
+         * for websocket, and require explicit config instead.
+         */
         displaynum = -1;
     }
 
@@ -3895,57 +3880,50 @@ static int vnc_display_get_addresses(QemuOpts *opts,
                                     has_ipv4, has_ipv6,
                                     ipv4, ipv6,
                                     &wsaddr, errp) < 0) {
-            goto cleanup;
+            return -1;
         }
 
         /* Historical compat - if only a single listen address was
          * provided, then this is used to set the default listen
          * address for websocket too
          */
-        if (*retnsaddr == 1 &&
-            (*retsaddr)[0]->type == SOCKET_ADDRESS_TYPE_INET &&
+        if (single_saddr &&
+            single_saddr->type == SOCKET_ADDRESS_TYPE_INET &&
             wsaddr->type == SOCKET_ADDRESS_TYPE_INET &&
             g_str_equal(wsaddr->u.inet.host, "") &&
-            !g_str_equal((*retsaddr)[0]->u.inet.host, "")) {
+            !g_str_equal(single_saddr->u.inet.host, "")) {
             g_free(wsaddr->u.inet.host);
-            wsaddr->u.inet.host = g_strdup((*retsaddr)[0]->u.inet.host);
+            wsaddr->u.inet.host = g_strdup(single_saddr->u.inet.host);
         }
 
-        *retwsaddr = g_renew(SocketAddress *, *retwsaddr, *retnwsaddr + 1);
-        (*retwsaddr)[(*retnwsaddr)++] = wsaddr;
+        QAPI_LIST_APPEND(wsaddr_tail, wsaddr);
     }
 
-    ret = 0;
- cleanup:
-    if (ret < 0) {
-        vnc_free_addresses(retsaddr, retnsaddr);
-        vnc_free_addresses(retwsaddr, retnwsaddr);
-    }
-    return ret;
+    *saddr_list_ret = g_steal_pointer(&saddr_list);
+    *wsaddr_list_ret = g_steal_pointer(&wsaddr_list);
+    return 0;
 }
 
 static int vnc_display_connect(VncDisplay *vd,
-                               SocketAddress **saddr,
-                               size_t nsaddr,
-                               SocketAddress **wsaddr,
-                               size_t nwsaddr,
+                               SocketAddressList *saddr_list,
+                               SocketAddressList *wsaddr_list,
                                Error **errp)
 {
     /* connect to viewer */
     QIOChannelSocket *sioc = NULL;
-    if (nwsaddr != 0) {
+    if (wsaddr_list) {
         error_setg(errp, "Cannot use websockets in reverse mode");
         return -1;
     }
-    if (nsaddr != 1) {
+    if (!saddr_list || saddr_list->next) {
         error_setg(errp, "Expected a single address in reverse mode");
         return -1;
     }
     /* TODO SOCKET_ADDRESS_TYPE_FD when fd has AF_UNIX */
-    vd->is_unix = saddr[0]->type == SOCKET_ADDRESS_TYPE_UNIX;
+    vd->is_unix = saddr_list->value->type == SOCKET_ADDRESS_TYPE_UNIX;
     sioc = qio_channel_socket_new();
     qio_channel_set_name(QIO_CHANNEL(sioc), "vnc-reverse");
-    if (qio_channel_socket_connect_sync(sioc, saddr[0], errp) < 0) {
+    if (qio_channel_socket_connect_sync(sioc, saddr_list->value, errp) < 0) {
         object_unref(OBJECT(sioc));
         return -1;
     }
@@ -3956,20 +3934,18 @@ static int vnc_display_connect(VncDisplay *vd,
 
 
 static int vnc_display_listen(VncDisplay *vd,
-                              SocketAddress **saddr,
-                              size_t nsaddr,
-                              SocketAddress **wsaddr,
-                              size_t nwsaddr,
+                              SocketAddressList *saddr_list,
+                              SocketAddressList *wsaddr_list,
                               Error **errp)
 {
-    size_t i;
+    SocketAddressList *el;
 
-    if (nsaddr) {
+    if (saddr_list) {
         vd->listener = qio_net_listener_new();
         qio_net_listener_set_name(vd->listener, "vnc-listen");
-        for (i = 0; i < nsaddr; i++) {
+        for (el = saddr_list; el; el = el->next) {
             if (qio_net_listener_open_sync(vd->listener,
-                                           saddr[i], 1,
+                                           el->value, 1,
                                            errp) < 0)  {
                 return -1;
             }
@@ -3979,12 +3955,12 @@ static int vnc_display_listen(VncDisplay *vd,
                                          vnc_listen_io, vd, NULL);
     }
 
-    if (nwsaddr) {
+    if (wsaddr_list) {
         vd->wslistener = qio_net_listener_new();
         qio_net_listener_set_name(vd->wslistener, "vnc-ws-listen");
-        for (i = 0; i < nwsaddr; i++) {
+        for (el = wsaddr_list; el; el = el->next) {
             if (qio_net_listener_open_sync(vd->wslistener,
-                                           wsaddr[i], 1,
+                                           el->value, 1,
                                            errp) < 0)  {
                 return -1;
             }
@@ -4002,8 +3978,8 @@ void vnc_display_open(const char *id, Error **errp)
 {
     VncDisplay *vd = vnc_display_find(id);
     QemuOpts *opts = qemu_opts_find(&qemu_vnc_opts, id);
-    SocketAddress **saddr = NULL, **wsaddr = NULL;
-    size_t nsaddr, nwsaddr;
+    g_autoptr(SocketAddressList) saddr_list = NULL;
+    g_autoptr(SocketAddressList) wsaddr_list = NULL;
     const char *share, *device_id;
     QemuConsole *con;
     bool password = false;
@@ -4028,8 +4004,8 @@ void vnc_display_open(const char *id, Error **errp)
     }
 
     reverse = qemu_opt_get_bool(opts, "reverse", false);
-    if (vnc_display_get_addresses(opts, reverse, &saddr, &nsaddr,
-                                  &wsaddr, &nwsaddr, errp) < 0) {
+    if (vnc_display_get_addresses(opts, reverse, &saddr_list, &wsaddr_list,
+                                  errp) < 0) {
         goto fail;
     }
 
@@ -4211,16 +4187,16 @@ void vnc_display_open(const char *id, Error **errp)
     }
     qkbd_state_set_delay(vd->kbd, key_delay_ms);
 
-    if (saddr == NULL) {
-        goto cleanup;
+    if (saddr_list == NULL) {
+        return;
     }
 
     if (reverse) {
-        if (vnc_display_connect(vd, saddr, nsaddr, wsaddr, nwsaddr, errp) < 0) {
+        if (vnc_display_connect(vd, saddr_list, wsaddr_list, errp) < 0) {
             goto fail;
         }
     } else {
-        if (vnc_display_listen(vd, saddr, nsaddr, wsaddr, nwsaddr, errp) < 0) {
+        if (vnc_display_listen(vd, saddr_list, wsaddr_list, errp) < 0) {
             goto fail;
         }
     }
@@ -4229,14 +4205,11 @@ void vnc_display_open(const char *id, Error **errp)
         vnc_display_print_local_addr(vd);
     }
 
- cleanup:
-    vnc_free_addresses(&saddr, &nsaddr);
-    vnc_free_addresses(&wsaddr, &nwsaddr);
+    /* Success */
     return;
 
 fail:
     vnc_display_close(vd);
-    goto cleanup;
 }
 
 void vnc_display_add_client(const char *id, int csock, bool skipauth)
-- 
2.31.1

[PATCH v2 2/3] qapi/ui: introduce change-vnc-listen

[Vladimir Sementsov-Ogievskiy]

Add command that can change addresses where VNC server listens for new
connections. Prior to 6.0 this functionality was available through
'change' qmp command which was deleted.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 docs/about/removed-features.rst |  3 ++-
 qapi/ui.json                    | 19 +++++++++++++++++++
 ui/vnc.c                        | 26 ++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index d42c3341de..20e6901a82 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -348,7 +348,8 @@ documentation of ``query-hotpluggable-cpus`` for additional details.
 ``change`` (removed in 6.0)
 '''''''''''''''''''''''''''
 
-Use ``blockdev-change-medium`` or ``change-vnc-password`` instead.
+Use ``blockdev-change-medium`` or ``change-vnc-password`` or
+``change-vnc-listen`` instead.
 
 ``query-events`` (removed in 6.0)
 '''''''''''''''''''''''''''''''''
diff --git a/qapi/ui.json b/qapi/ui.json
index 2b4371da37..6a586edff1 100644
--- a/qapi/ui.json
+++ b/qapi/ui.json
@@ -1334,3 +1334,22 @@
 { 'command': 'display-reload',
   'data': 'DisplayReloadOptions',
   'boxed' : true }
+
+##
+# @change-vnc-listen:
+#
+# Change set of addresses to listen for connections.
+#
+# @id: vnc display identifier
+#
+# @addresses: list of addresses for listen at
+#
+# @websockets: list of addresses to listen with websockets
+#
+# Since: 7.0
+#
+##
+{ 'command': 'change-vnc-listen',
+  'data': { 'id': 'str', 'addresses': ['SocketAddress'],
+            '*websockets': ['SocketAddress'] },
+  'if': 'CONFIG_VNC' }
diff --git a/ui/vnc.c b/ui/vnc.c
index e8430531c0..d7d0d255fc 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -4212,6 +4212,32 @@ fail:
     vnc_display_close(vd);
 }
 
+void qmp_change_vnc_listen(const char *id, SocketAddressList *addresses,
+                           bool has_websockets, SocketAddressList *websockets,
+                           Error **errp)
+{
+    VncDisplay *vd = vnc_display_find(id);
+
+    if (!vd) {
+        error_setg(errp, "VNC display '%s' not active", id);
+        return;
+    }
+
+    if (vd->listener) {
+        qio_net_listener_disconnect(vd->listener);
+        object_unref(OBJECT(vd->listener));
+    }
+    vd->listener = NULL;
+
+    if (vd->wslistener) {
+        qio_net_listener_disconnect(vd->wslistener);
+        object_unref(OBJECT(vd->wslistener));
+    }
+    vd->wslistener = NULL;
+
+    vnc_display_listen(vd, addresses, websockets, errp);
+}
+
 void vnc_display_add_client(const char *id, int csock, bool skipauth)
 {
     VncDisplay *vd = vnc_display_find(id);
-- 
2.31.1

Re: [PATCH v2 2/3] qapi/ui: introduce change-vnc-listen

[Daniel P. Berrangé]

On Wed, Dec 22, 2021 at 08:17:30PM +0100, Vladimir Sementsov-Ogievskiy wrote:
> Add command that can change addresses where VNC server listens for new
> connections. Prior to 6.0 this functionality was available through
> 'change' qmp command which was deleted.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  docs/about/removed-features.rst |  3 ++-
>  qapi/ui.json                    | 19 +++++++++++++++++++
>  ui/vnc.c                        | 26 ++++++++++++++++++++++++++
>  3 files changed, 47 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
> index d42c3341de..20e6901a82 100644
> --- a/docs/about/removed-features.rst
> +++ b/docs/about/removed-features.rst
> @@ -348,7 +348,8 @@ documentation of ``query-hotpluggable-cpus`` for additional details.
>  ``change`` (removed in 6.0)
>  '''''''''''''''''''''''''''
>  
> -Use ``blockdev-change-medium`` or ``change-vnc-password`` instead.
> +Use ``blockdev-change-medium`` or ``change-vnc-password`` or
> +``change-vnc-listen`` instead.
>  
>  ``query-events`` (removed in 6.0)
>  '''''''''''''''''''''''''''''''''
> diff --git a/qapi/ui.json b/qapi/ui.json
> index 2b4371da37..6a586edff1 100644
> --- a/qapi/ui.json
> +++ b/qapi/ui.json
> @@ -1334,3 +1334,22 @@
>  { 'command': 'display-reload',
>    'data': 'DisplayReloadOptions',
>    'boxed' : true }
> +
> +##
> +# @change-vnc-listen:
> +#
> +# Change set of addresses to listen for connections.
> +#
> +# @id: vnc display identifier
> +#
> +# @addresses: list of addresses for listen at
> +#
> +# @websockets: list of addresses to listen with websockets
> +#
> +# Since: 7.0
> +#
> +##
> +{ 'command': 'change-vnc-listen',
> +  'data': { 'id': 'str', 'addresses': ['SocketAddress'],
> +            '*websockets': ['SocketAddress'] },
> +  'if': 'CONFIG_VNC' }

I replied to your v1 before noticing this v2. So this is just to
point out that I suggested we could use 'display-reload' to update
the address rather than adding a new command.


Regards,
Daniel
-- 
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[PATCH v2 3/3] avocado/vnc: add test_change_listen

[Vladimir Sementsov-Ogievskiy]

Add simple test-case for new change-vnc-listen qmp command.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 tests/avocado/vnc.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/avocado/vnc.py b/tests/avocado/vnc.py
index 096432988f..f05ee1e00a 100644
--- a/tests/avocado/vnc.py
+++ b/tests/avocado/vnc.py
@@ -51,3 +51,13 @@ def test_change_password(self):
         set_password_response = self.vm.qmp('change-vnc-password',
                                             password='new_password')
         self.assertEqual(set_password_response['return'], {})
+
+    def test_change_listen(self):
+        self.vm.add_args('-nodefaults', '-S', '-vnc', ':0')
+        self.vm.launch()
+        self.assertEqual(self.vm.qmp('query-vnc')['return']['service'], '5900')
+        res = self.vm.qmp('change-vnc-listen', id='default',
+                          addresses=[{'type': 'inet', 'host': '0.0.0.0',
+                                      'port': '5901'}])
+        self.assertEqual(res['return'], {})
+        self.assertEqual(self.vm.qmp('query-vnc')['return']['service'], '5901')
-- 
2.31.1