[Qemu-devel] [PULL v2 0/8] Merge io/ 2017-01-23

[Qemu-devel] [PULL v2 0/8] Merge io/ 2017-01-23

[Daniel P. Berrange]

The following changes since commit 598cf1c805271564686f2d732b36f50c3c40dcdd:

  Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging (2017-01-20 16:42:07 +0000)

are available in the git repository at:

  git://github.com/berrange/qemu tags/pull-qio-2017-01-23-2

for you to fetch changes up to c1b412f1d94ba717896f876dbf59fffa91e596fc:

  io: introduce a DNS resolver API (2017-01-23 15:32:46 +0000)

----------------------------------------------------------------
Merge io/ 2017-01-23

----------------------------------------------------------------

Daniel P. Berrange (8):
  sockets: add ability to disable DNS resolution for InetSocketAddress
  io: stop incrementing reference in qio_task_get_source
  io: fix typo in docs for QIOTask
  io: add ability to associate an opaque "result" with with a task
  io: add ability to associate an error with a task
  io: change the QIOTask callback signature
  io: remove Error parameter from QIOTask thread worker
  io: introduce a DNS resolver API

 include/io/dns-resolver.h      | 228 ++++++++++++++++++++++++++++++++++
 include/io/task.h              | 154 ++++++++++++++++-------
 include/qemu/sockets.h         |   2 +
 io/Makefile.objs               |   1 +
 io/channel-socket.c            |  44 +++----
 io/channel-tls.c               |  16 +--
 io/channel-websock.c           |   8 +-
 io/dns-resolver.c              | 276 +++++++++++++++++++++++++++++++++++++++++
 io/task.c                      |  62 ++++++---
 io/trace-events                |   1 -
 migration/socket.c             |  11 +-
 migration/tls.c                |  19 +--
 nbd/common.c                   |   8 +-
 nbd/nbd-internal.h             |   3 +-
 qapi-schema.json               |   5 +
 qemu-char.c                    |  18 +--
 tests/test-io-channel-socket.c |   5 +-
 tests/test-io-channel-tls.c    |   5 +-
 tests/test-io-task.c           |  31 ++---
 ui/vnc-auth-vencrypt.c         |   7 +-
 ui/vnc-ws.c                    |  14 ++-
 util/qemu-sockets.c            |  11 +-
 22 files changed, 760 insertions(+), 169 deletions(-)
 create mode 100644 include/io/dns-resolver.h
 create mode 100644 io/dns-resolver.c

-- 
2.9.3

[Qemu-devel] [PULL v2 1/8] sockets: add ability to disable DNS resolution for InetSocketAddress

[Daniel P. Berrange]

Add a 'numeric' flag to the InetSocketAddress struct to allow the
caller to indicate that DNS should be skipped for the host/port
fields. This is useful if the caller knows the address is already
numeric and wants to guarantee no (potentially blocking) DNS
lookups are attempted.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 qapi-schema.json    | 5 +++++
 util/qemu-sockets.c | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/qapi-schema.json b/qapi-schema.json
index ddc8783..ac55f4a 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3983,6 +3983,10 @@
 #
 # @port: port part of the address, or lowest port if @to is present
 #
+# @numeric: #optional true if the host/port are guaranteed to be numeric,
+#           false if name resolution should be attempted. Defaults to false.
+#           (Since 2.9)
+#
 # @to: highest port to try
 #
 # @ipv4: whether to accept IPv4 addresses, default try both IPv4 and IPv6
@@ -3997,6 +4001,7 @@
   'data': {
     'host': 'str',
     'port': 'str',
+    '*numeric':  'bool',
     '*to': 'uint16',
     '*ipv4': 'bool',
     '*ipv6': 'bool' } }
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index fe1d07a..b6d99cb 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -38,6 +38,10 @@
 # define AI_V4MAPPED 0
 #endif
 
+#ifndef AI_NUMERICSERV
+# define AI_NUMERICSERV 0
+#endif
+
 
 static int inet_getport(struct addrinfo *e)
 {
@@ -141,6 +145,9 @@ static int inet_listen_saddr(InetSocketAddress *saddr,
 
     memset(&ai,0, sizeof(ai));
     ai.ai_flags = AI_PASSIVE;
+    if (saddr->has_numeric && saddr->numeric) {
+        ai.ai_flags |= AI_NUMERICHOST | AI_NUMERICSERV;
+    }
     ai.ai_family = inet_ai_family_from_address(saddr, &err);
     ai.ai_socktype = SOCK_STREAM;
 
-- 
2.9.3

[Qemu-devel] [PULL v2 2/8] io: stop incrementing reference in qio_task_get_source

[Daniel P. Berrange]

Incrementing the reference in qio_task_get_source is
not necessary, since we're not running concurrently
with any other code touching the QIOTask. This
minimizes chances of further memory leaks.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/io/task.h    | 7 ++++---
 io/channel-socket.c  | 3 ---
 io/channel-tls.c     | 2 --
 io/task.c            | 1 -
 tests/test-io-task.c | 1 -
 5 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/include/io/task.h b/include/io/task.h
index 42028cb..c268eb0 100644
--- a/include/io/task.h
+++ b/include/io/task.h
@@ -244,9 +244,10 @@ void qio_task_abort(QIOTask *task,
  * @task: the task struct
  *
  * Get the source object associated with the background
- * task. This returns a new reference to the object,
- * which the caller must released with object_unref()
- * when no longer required.
+ * task. The caller does not own a reference on the
+ * returned Object, and so should call object_ref()
+ * if it wants to keep the object pointer outside the
+ * lifetime of the QIOTask object.
  *
  * Returns: the source object
  */
diff --git a/io/channel-socket.c b/io/channel-socket.c
index d7e03f6..45df819 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -168,7 +168,6 @@ static int qio_channel_socket_connect_worker(QIOTask *task,
                                           addr,
                                           errp);
 
-    object_unref(OBJECT(ioc));
     return ret;
 }
 
@@ -231,7 +230,6 @@ static int qio_channel_socket_listen_worker(QIOTask *task,
                                          addr,
                                          errp);
 
-    object_unref(OBJECT(ioc));
     return ret;
 }
 
@@ -309,7 +307,6 @@ static int qio_channel_socket_dgram_worker(QIOTask *task,
                                         data->remoteAddr,
                                         errp);
 
-    object_unref(OBJECT(ioc));
     return ret;
 }
 
diff --git a/io/channel-tls.c b/io/channel-tls.c
index d24dc8c..cf3bcca 100644
--- a/io/channel-tls.c
+++ b/io/channel-tls.c
@@ -200,8 +200,6 @@ static gboolean qio_channel_tls_handshake_io(QIOChannel *ioc,
     qio_channel_tls_handshake_task(
        tioc, task);
 
-    object_unref(OBJECT(tioc));
-
     return FALSE;
 }
 
diff --git a/io/task.c b/io/task.c
index c7f97a9..a763990 100644
--- a/io/task.c
+++ b/io/task.c
@@ -156,6 +156,5 @@ void qio_task_abort(QIOTask *task,
 
 Object *qio_task_get_source(QIOTask *task)
 {
-    object_ref(task->source);
     return task->source;
 }
diff --git a/tests/test-io-task.c b/tests/test-io-task.c
index e091c12..024eb58 100644
--- a/tests/test-io-task.c
+++ b/tests/test-io-task.c
@@ -76,7 +76,6 @@ static void test_task_complete(void)
     g_assert(obj == src);
 
     object_unref(obj);
-    object_unref(src);
 
     g_assert(data.source == obj);
     g_assert(data.err == NULL);
-- 
2.9.3

[Qemu-devel] [PULL v2 3/8] io: fix typo in docs for QIOTask

[Daniel P. Berrange]

The GDestroyNotify parameter is already a pointer, so does
not need a '*' suffix on the type.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/io/task.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/io/task.h b/include/io/task.h
index c268eb0..1407747 100644
--- a/include/io/task.h
+++ b/include/io/task.h
@@ -49,7 +49,7 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  *  void myobject_operation(QMyObject *obj,
  *                          QIOTaskFunc *func,
  *                          gpointer opaque,
- *                          GDestroyNotify *notify);
+ *                          GDestroyNotify notify);
  *   </programlisting>
  * </example>
  *
@@ -67,7 +67,7 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  *    void myobject_operation(QMyObject *obj,
  *                            QIOTaskFunc *func,
  *                            gpointer opaque,
- *                            GDestroyNotify *notify)
+ *                            GDestroyNotify notify)
  *    {
  *      QIOTask *task;
  *
@@ -154,7 +154,7 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  *                               SocketAddress *addr,
  *                               QIOTaskFunc *func,
  *                               gpointer opaque,
- *                               GDestroyNotify *notify)
+ *                               GDestroyNotify notify)
  *    {
  *      QIOTask *task;
  *      SocketAddress *addrCopy;
-- 
2.9.3

[Qemu-devel] [PULL v2 4/8] io: add ability to associate an opaque "result" with with a task

[Daniel P. Berrange]

Currently there is no data associated with a successful
task completion. This adds an opaque pointer to the task
to store an arbitrary result.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/io/task.h | 27 +++++++++++++++++++++++++++
 io/task.c         | 20 ++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/include/io/task.h b/include/io/task.h
index 1407747..ece1372 100644
--- a/include/io/task.h
+++ b/include/io/task.h
@@ -240,6 +240,33 @@ void qio_task_abort(QIOTask *task,
 
 
 /**
+ * qio_task_set_result_pointer:
+ * @task: the task struct
+ * @result: pointer to the result data
+ *
+ * Associate an opaque result with the task,
+ * which can later be retrieved with the
+ * qio_task_get_result_pointer() method
+ *
+ */
+void qio_task_set_result_pointer(QIOTask *task,
+                                 gpointer result,
+                                 GDestroyNotify notify);
+
+
+/**
+ * qio_task_get_result_pointer:
+ * @task: the task struct
+ *
+ * Retrieve the opaque result data associated
+ * with the task, if any.
+ *
+ * Returns: the task result, or NULL
+ */
+gpointer qio_task_get_result_pointer(QIOTask *task);
+
+
+/**
  * qio_task_get_source:
  * @task: the task struct
  *
diff --git a/io/task.c b/io/task.c
index a763990..675e196 100644
--- a/io/task.c
+++ b/io/task.c
@@ -29,6 +29,8 @@ struct QIOTask {
     QIOTaskFunc func;
     gpointer opaque;
     GDestroyNotify destroy;
+    gpointer result;
+    GDestroyNotify destroyResult;
 };
 
 
@@ -57,6 +59,9 @@ static void qio_task_free(QIOTask *task)
     if (task->destroy) {
         task->destroy(task->opaque);
     }
+    if (task->destroyResult) {
+        task->destroyResult(task->result);
+    }
     object_unref(task->source);
 
     g_free(task);
@@ -154,6 +159,21 @@ void qio_task_abort(QIOTask *task,
 }
 
 
+void qio_task_set_result_pointer(QIOTask *task,
+                                 gpointer result,
+                                 GDestroyNotify destroy)
+{
+    task->result = result;
+    task->destroyResult = destroy;
+}
+
+
+gpointer qio_task_get_result_pointer(QIOTask *task)
+{
+    return task->result;
+}
+
+
 Object *qio_task_get_source(QIOTask *task)
 {
     return task->source;
-- 
2.9.3

[Qemu-devel] [PULL v2 5/8] io: add ability to associate an error with a task

[Daniel P. Berrange]

Currently when a task fails, the error is never explicitly
associated with the task object, it is just passed along
through the completion callback. This adds the ability to
explicitly associate an error with the task.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/io/task.h | 32 ++++++++++++++++++++++++++++++++
 io/task.c         | 23 +++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/include/io/task.h b/include/io/task.h
index ece1372..47daba9 100644
--- a/include/io/task.h
+++ b/include/io/task.h
@@ -240,6 +240,38 @@ void qio_task_abort(QIOTask *task,
 
 
 /**
+ * qio_task_set_error:
+ * @task: the task struct
+ * @err: pointer to the error, or NULL
+ *
+ * Associate an error with the task, which can later
+ * be retrieved with the qio_task_propagate_error()
+ * method. This method takes ownership of @err, so
+ * it is not valid to access it after this call
+ * completes. If @err is NULL this is a no-op. If
+ * this is call multiple times, only the first
+ * provided @err will be recorded, later ones will
+ * be discarded and freed.
+ */
+void qio_task_set_error(QIOTask *task,
+                        Error *err);
+
+
+/**
+ * qio_task_propagate_error:
+ * @task: the task struct
+ * @errp: pointer to a NULL-initialized error object
+ *
+ * Propagate the error associated with @task
+ * into @errp.
+ *
+ * Returns: true if an error was propagated, false otherwise
+ */
+bool qio_task_propagate_error(QIOTask *task,
+                              Error **errp);
+
+
+/**
  * qio_task_set_result_pointer:
  * @task: the task struct
  * @result: pointer to the result data
diff --git a/io/task.c b/io/task.c
index 675e196..1394e05 100644
--- a/io/task.c
+++ b/io/task.c
@@ -29,6 +29,7 @@ struct QIOTask {
     QIOTaskFunc func;
     gpointer opaque;
     GDestroyNotify destroy;
+    Error *err;
     gpointer result;
     GDestroyNotify destroyResult;
 };
@@ -62,6 +63,9 @@ static void qio_task_free(QIOTask *task)
     if (task->destroyResult) {
         task->destroyResult(task->result);
     }
+    if (task->err) {
+        error_free(task->err);
+    }
     object_unref(task->source);
 
     g_free(task);
@@ -159,6 +163,25 @@ void qio_task_abort(QIOTask *task,
 }
 
 
+void qio_task_set_error(QIOTask *task,
+                        Error *err)
+{
+    error_propagate(&task->err, err);
+}
+
+
+bool qio_task_propagate_error(QIOTask *task,
+                              Error **errp)
+{
+    if (task->err) {
+        error_propagate(errp, task->err);
+        return true;
+    }
+
+    return false;
+}
+
+
 void qio_task_set_result_pointer(QIOTask *task,
                                  gpointer result,
                                  GDestroyNotify destroy)
-- 
2.9.3

[Qemu-devel] [PULL v2 6/8] io: change the QIOTask callback signature

[Daniel P. Berrange]

Currently the QIOTaskFunc signature takes an Object * for
the source, and an Error * for any error. We also need to
be able to provide a result pointer. Rather than continue
to add parameters to QIOTaskFunc, remove the existing
ones and simply pass the QIOTask object instead. This
has methods to access all the other data items required
in the callback impl.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/io/task.h              | 73 ++++++++++++++++++++++++------------------
 io/channel-tls.c               | 14 ++++----
 io/channel-websock.c           |  8 ++---
 io/task.c                      | 18 +++--------
 io/trace-events                |  1 -
 migration/socket.c             | 11 ++++---
 migration/tls.c                | 19 +++++------
 nbd/common.c                   |  8 ++---
 nbd/nbd-internal.h             |  3 +-
 qemu-char.c                    | 18 ++++++-----
 tests/test-io-channel-socket.c |  5 ++-
 tests/test-io-channel-tls.c    |  5 ++-
 tests/test-io-task.c           | 18 +++++------
 ui/vnc-auth-vencrypt.c         |  7 ++--
 ui/vnc-ws.c                    | 14 ++++----
 15 files changed, 110 insertions(+), 112 deletions(-)

diff --git a/include/io/task.h b/include/io/task.h
index 47daba9..ad90970 100644
--- a/include/io/task.h
+++ b/include/io/task.h
@@ -26,8 +26,7 @@
 
 typedef struct QIOTask QIOTask;
 
-typedef void (*QIOTaskFunc)(Object *source,
-                            Error *err,
+typedef void (*QIOTaskFunc)(QIOTask *task,
                             gpointer opaque);
 
 typedef int (*QIOTaskWorker)(QIOTask *task,
@@ -44,7 +43,7 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  * a public API which accepts a task callback:
  *
  * <example>
- *   <title>Task callback function signature</title>
+ *   <title>Task function signature</title>
  *   <programlisting>
  *  void myobject_operation(QMyObject *obj,
  *                          QIOTaskFunc *func,
@@ -57,12 +56,36 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  * is data to pass to it. The optional 'notify' function is used
  * to free 'opaque' when no longer needed.
  *
- * Now, lets say the implementation of this method wants to set
- * a timer to run once a second checking for completion of some
- * activity. It would do something like
+ * When the operation completes, the 'func' callback will be
+ * invoked, allowing the calling code to determine the result
+ * of the operation. An example QIOTaskFunc implementation may
+ * look like
  *
  * <example>
- *   <title>Task callback function implementation</title>
+ *   <title>Task callback implementation</title>
+ *   <programlisting>
+ *  static void myobject_operation_notify(QIOTask *task,
+ *                                        gpointer opaque)
+ *  {
+ *      Error *err = NULL;
+ *      if (qio_task_propagate_error(task, &err)) {
+ *          ...deal with the failure...
+ *          error_free(err);
+ *      } else {
+ *          QMyObject *src = QMY_OBJECT(qio_task_get_source(task));
+ *          ...deal with the completion...
+ *      }
+ *  }
+ *   </programlisting>
+ * </example>
+ *
+ * Now, lets say the implementation of the method using the
+ * task wants to set a timer to run once a second checking
+ * for completion of some activity. It would do something
+ * like
+ *
+ * <example>
+ *   <title>Task function implementation</title>
  *   <programlisting>
  *    void myobject_operation(QMyObject *obj,
  *                            QIOTaskFunc *func,
@@ -102,8 +125,8 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  *
  *      ...check something important...
  *       if (err) {
- *           qio_task_abort(task, err);
- *           error_free(task);
+ *           qio_task_set_error(task, err);
+ *           qio_task_complete(task);
  *           return FALSE;
  *       } else if (...work is completed ...) {
  *           qio_task_complete(task);
@@ -115,6 +138,10 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  *   </programlisting>
  * </example>
  *
+ * The 'qio_task_complete' call in this method will trigger
+ * the callback func 'myobject_operation_notify' shown
+ * earlier to deal with the results.
+ *
  * Once this function returns false, object_unref will be called
  * automatically on the task causing it to be released and the
  * ref on QMyObject dropped too.
@@ -187,8 +214,8 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  * 'err' attribute in the task object to determine if
  * the operation was successful or not.
  *
- * The returned task will be released when one of
- * qio_task_abort() or qio_task_complete() are invoked.
+ * The returned task will be released when qio_task_complete()
+ * is invoked.
  *
  * Returns: the task struct
  */
@@ -204,10 +231,8 @@ QIOTask *qio_task_new(Object *source,
  * @opaque: opaque data to pass to @worker
  * @destroy: function to free @opaque
  *
- * Run a task in a background thread. If @worker
- * returns 0 it will call qio_task_complete() in
- * the main event thread context. If @worker
- * returns -1 it will call qio_task_abort() in
+ * Run a task in a background thread. When @worker
+ * returns it will call qio_task_complete() in
  * the main event thread context.
  */
 void qio_task_run_in_thread(QIOTask *task,
@@ -219,25 +244,11 @@ void qio_task_run_in_thread(QIOTask *task,
  * qio_task_complete:
  * @task: the task struct
  *
- * Mark the operation as successfully completed
- * and free the memory for @task.
+ * Invoke the completion callback for @task and
+ * then free its memory.
  */
 void qio_task_complete(QIOTask *task);
 
-/**
- * qio_task_abort:
- * @task: the task struct
- * @err: the error to record for the operation
- *
- * Mark the operation as failed, with @err providing
- * details about the failure. The @err may be freed
- * afer the function returns, as the notification
- * callback is invoked synchronously. The @task will
- * be freed when this call completes.
- */
-void qio_task_abort(QIOTask *task,
-                    Error *err);
-
 
 /**
  * qio_task_set_error:
diff --git a/io/channel-tls.c b/io/channel-tls.c
index cf3bcca..f25ab0a 100644
--- a/io/channel-tls.c
+++ b/io/channel-tls.c
@@ -153,8 +153,9 @@ static void qio_channel_tls_handshake_task(QIOChannelTLS *ioc,
 
     if (qcrypto_tls_session_handshake(ioc->session, &err) < 0) {
         trace_qio_channel_tls_handshake_fail(ioc);
-        qio_task_abort(task, err);
-        goto cleanup;
+        qio_task_set_error(task, err);
+        qio_task_complete(task);
+        return;
     }
 
     status = qcrypto_tls_session_get_handshake_status(ioc->session);
@@ -163,10 +164,10 @@ static void qio_channel_tls_handshake_task(QIOChannelTLS *ioc,
         if (qcrypto_tls_session_check_credentials(ioc->session,
                                                   &err) < 0) {
             trace_qio_channel_tls_credentials_deny(ioc);
-            qio_task_abort(task, err);
-            goto cleanup;
+            qio_task_set_error(task, err);
+        } else {
+            trace_qio_channel_tls_credentials_allow(ioc);
         }
-        trace_qio_channel_tls_credentials_allow(ioc);
         qio_task_complete(task);
     } else {
         GIOCondition condition;
@@ -183,9 +184,6 @@ static void qio_channel_tls_handshake_task(QIOChannelTLS *ioc,
                               task,
                               NULL);
     }
-
- cleanup:
-    error_free(err);
 }
 
 
diff --git a/io/channel-websock.c b/io/channel-websock.c
index f45bced..e47279a 100644
--- a/io/channel-websock.c
+++ b/io/channel-websock.c
@@ -279,8 +279,8 @@ static gboolean qio_channel_websock_handshake_send(QIOChannel *ioc,
 
     if (ret < 0) {
         trace_qio_channel_websock_handshake_fail(ioc);
-        qio_task_abort(task, err);
-        error_free(err);
+        qio_task_set_error(task, err);
+        qio_task_complete(task);
         return FALSE;
     }
 
@@ -307,8 +307,8 @@ static gboolean qio_channel_websock_handshake_io(QIOChannel *ioc,
     ret = qio_channel_websock_handshake_read(wioc, &err);
     if (ret < 0) {
         trace_qio_channel_websock_handshake_fail(ioc);
-        qio_task_abort(task, err);
-        error_free(err);
+        qio_task_set_error(task, err);
+        qio_task_complete(task);
         return FALSE;
     }
     if (ret == 0) {
diff --git a/io/task.c b/io/task.c
index 1394e05..42e1a75 100644
--- a/io/task.c
+++ b/io/task.c
@@ -87,13 +87,11 @@ static gboolean gio_task_thread_result(gpointer opaque)
     struct QIOTaskThreadData *data = opaque;
 
     trace_qio_task_thread_result(data->task);
-    if (data->ret == 0) {
-        qio_task_complete(data->task);
-    } else {
-        qio_task_abort(data->task, data->err);
+    if (data->err) {
+        qio_task_set_error(data->task, data->err);
     }
+    qio_task_complete(data->task);
 
-    error_free(data->err);
     if (data->destroy) {
         data->destroy(data->opaque);
     }
@@ -149,19 +147,11 @@ void qio_task_run_in_thread(QIOTask *task,
 
 void qio_task_complete(QIOTask *task)
 {
-    task->func(task->source, NULL, task->opaque);
+    task->func(task, task->opaque);
     trace_qio_task_complete(task);
     qio_task_free(task);
 }
 
-void qio_task_abort(QIOTask *task,
-                    Error *err)
-{
-    task->func(task->source, err, task->opaque);
-    trace_qio_task_abort(task);
-    qio_task_free(task);
-}
-
 
 void qio_task_set_error(QIOTask *task,
                         Error *err)
diff --git a/io/trace-events b/io/trace-events
index e31b596..ff993be 100644
--- a/io/trace-events
+++ b/io/trace-events
@@ -3,7 +3,6 @@
 # io/task.c
 qio_task_new(void *task, void *source, void *func, void *opaque) "Task new task=%p source=%p func=%p opaque=%p"
 qio_task_complete(void *task) "Task complete task=%p"
-qio_task_abort(void *task) "Task abort task=%p"
 qio_task_thread_start(void *task, void *worker, void *opaque) "Task thread start task=%p worker=%p opaque=%p"
 qio_task_thread_run(void *task) "Task thread run task=%p"
 qio_task_thread_exit(void *task) "Task thread exit task=%p"
diff --git a/migration/socket.c b/migration/socket.c
index 11f80b1..13966f1 100644
--- a/migration/socket.c
+++ b/migration/socket.c
@@ -70,22 +70,23 @@ static void socket_connect_data_free(void *opaque)
     g_free(data);
 }
 
-static void socket_outgoing_migration(Object *src,
-                                      Error *err,
+static void socket_outgoing_migration(QIOTask *task,
                                       gpointer opaque)
 {
     struct SocketConnectData *data = opaque;
-    QIOChannel *sioc = QIO_CHANNEL(src);
+    QIOChannel *sioc = QIO_CHANNEL(qio_task_get_source(task));
+    Error *err = NULL;
 
-    if (err) {
+    if (qio_task_propagate_error(task, &err)) {
         trace_migration_socket_outgoing_error(error_get_pretty(err));
         data->s->to_dst_file = NULL;
         migrate_fd_error(data->s, err);
+        error_free(err);
     } else {
         trace_migration_socket_outgoing_connected(data->hostname);
         migration_channel_connect(data->s, sioc, data->hostname);
     }
-    object_unref(src);
+    object_unref(OBJECT(sioc));
 }
 
 static void socket_start_outgoing_migration(MigrationState *s,
diff --git a/migration/tls.c b/migration/tls.c
index 49ca9a8..203c11d 100644
--- a/migration/tls.c
+++ b/migration/tls.c
@@ -61,15 +61,15 @@ migration_tls_get_creds(MigrationState *s,
 }
 
 
-static void migration_tls_incoming_handshake(Object *src,
-                                             Error *err,
+static void migration_tls_incoming_handshake(QIOTask *task,
                                              gpointer opaque)
 {
-    QIOChannel *ioc = QIO_CHANNEL(src);
+    QIOChannel *ioc = QIO_CHANNEL(qio_task_get_source(task));
+    Error *err = NULL;
 
-    if (err) {
+    if (qio_task_propagate_error(task, &err)) {
         trace_migration_tls_incoming_handshake_error(error_get_pretty(err));
-        error_report("%s", error_get_pretty(err));
+        error_report_err(err);
     } else {
         trace_migration_tls_incoming_handshake_complete();
         migration_channel_process_incoming(migrate_get_current(), ioc);
@@ -107,17 +107,18 @@ void migration_tls_channel_process_incoming(MigrationState *s,
 }
 
 
-static void migration_tls_outgoing_handshake(Object *src,
-                                             Error *err,
+static void migration_tls_outgoing_handshake(QIOTask *task,
                                              gpointer opaque)
 {
     MigrationState *s = opaque;
-    QIOChannel *ioc = QIO_CHANNEL(src);
+    QIOChannel *ioc = QIO_CHANNEL(qio_task_get_source(task));
+    Error *err = NULL;
 
-    if (err) {
+    if (qio_task_propagate_error(task, &err)) {
         trace_migration_tls_outgoing_handshake_error(error_get_pretty(err));
         s->to_dst_file = NULL;
         migrate_fd_error(s, err);
+        error_free(err);
     } else {
         trace_migration_tls_outgoing_handshake_complete();
         migration_channel_connect(s, ioc, NULL);
diff --git a/nbd/common.c b/nbd/common.c
index b583a4f..a5f39ea 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -78,15 +78,13 @@ ssize_t nbd_wr_syncv(QIOChannel *ioc,
 }
 
 
-void nbd_tls_handshake(Object *src,
-                       Error *err,
+void nbd_tls_handshake(QIOTask *task,
                        void *opaque)
 {
     struct NBDTLSHandshakeData *data = opaque;
 
-    if (err) {
-        TRACE("TLS failed %s", error_get_pretty(err));
-        data->error = error_copy(err);
+    if (qio_task_propagate_error(task, &data->error)) {
+        TRACE("TLS failed %s", error_get_pretty(data->error));
     }
     data->complete = true;
     g_main_loop_quit(data->loop);
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h
index eee20ab..f43d990 100644
--- a/nbd/nbd-internal.h
+++ b/nbd/nbd-internal.h
@@ -120,8 +120,7 @@ struct NBDTLSHandshakeData {
 };
 
 
-void nbd_tls_handshake(Object *src,
-                       Error *err,
+void nbd_tls_handshake(QIOTask *task,
                        void *opaque);
 
 #endif
diff --git a/qemu-char.c b/qemu-char.c
index 676944a..d8da167 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3277,14 +3277,13 @@ static void tcp_chr_telnet_init(CharDriverState *chr)
 }
 
 
-static void tcp_chr_tls_handshake(Object *source,
-                                  Error *err,
+static void tcp_chr_tls_handshake(QIOTask *task,
                                   gpointer user_data)
 {
     CharDriverState *chr = user_data;
     TCPCharDriver *s = chr->opaque;
 
-    if (err) {
+    if (qio_task_propagate_error(task, NULL)) {
         tcp_chr_disconnect(chr);
     } else {
         if (s->do_telnetopt) {
@@ -3492,20 +3491,23 @@ static void tcp_chr_free(CharDriverState *chr)
 }
 
 
-static void qemu_chr_socket_connected(Object *src, Error *err, void *opaque)
+static void qemu_chr_socket_connected(QIOTask *task, void *opaque)
 {
-    QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(src);
+    QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(qio_task_get_source(task));
     CharDriverState *chr = opaque;
     TCPCharDriver *s = chr->opaque;
+    Error *err = NULL;
 
-    if (err) {
+    if (qio_task_propagate_error(task, &err)) {
         check_report_connect_error(chr, err);
-        object_unref(src);
-        return;
+        error_free(err);
+        goto cleanup;
     }
 
     s->connect_err_reported = false;
     tcp_chr_new_client(chr, sioc);
+
+ cleanup:
     object_unref(OBJECT(sioc));
 }
 
diff --git a/tests/test-io-channel-socket.c b/tests/test-io-channel-socket.c
index aa88c3c..aaa9116 100644
--- a/tests/test-io-channel-socket.c
+++ b/tests/test-io-channel-socket.c
@@ -156,12 +156,11 @@ struct TestIOChannelData {
 };
 
 
-static void test_io_channel_complete(Object *src,
-                                     Error *err,
+static void test_io_channel_complete(QIOTask *task,
                                      gpointer opaque)
 {
     struct TestIOChannelData *data = opaque;
-    data->err = err != NULL;
+    data->err = qio_task_propagate_error(task, NULL);
     g_main_loop_quit(data->loop);
 }
 
diff --git a/tests/test-io-channel-tls.c b/tests/test-io-channel-tls.c
index bd3ae2b..8eaa208 100644
--- a/tests/test-io-channel-tls.c
+++ b/tests/test-io-channel-tls.c
@@ -53,14 +53,13 @@ struct QIOChannelTLSHandshakeData {
     bool failed;
 };
 
-static void test_tls_handshake_done(Object *source,
-                                    Error *err,
+static void test_tls_handshake_done(QIOTask *task,
                                     gpointer opaque)
 {
     struct QIOChannelTLSHandshakeData *data = opaque;
 
     data->finished = true;
-    data->failed = err != NULL;
+    data->failed = qio_task_propagate_error(task, NULL);
 }
 
 
diff --git a/tests/test-io-task.c b/tests/test-io-task.c
index 024eb58..84144c9 100644
--- a/tests/test-io-task.c
+++ b/tests/test-io-task.c
@@ -50,14 +50,13 @@ struct TestTaskData {
 };
 
 
-static void task_callback(Object *source,
-                          Error *err,
+static void task_callback(QIOTask *task,
                           gpointer opaque)
 {
     struct TestTaskData *data = opaque;
 
-    data->source = source;
-    data->err = err;
+    data->source = qio_task_get_source(task);
+    qio_task_propagate_error(task, &data->err);
 }
 
 
@@ -120,9 +119,9 @@ static void test_task_failure(void)
 
     error_setg(&err, "Some error");
 
-    qio_task_abort(task, err);
+    qio_task_set_error(task, err);
+    qio_task_complete(task);
 
-    error_free(err);
     object_unref(obj);
 
     g_assert(data.source == obj);
@@ -158,14 +157,13 @@ static int test_task_thread_worker(QIOTask *task,
 }
 
 
-static void test_task_thread_callback(Object *source,
-                                      Error *err,
+static void test_task_thread_callback(QIOTask *task,
                                       gpointer opaque)
 {
     struct TestThreadWorkerData *data = opaque;
 
-    data->source = source;
-    data->err = err;
+    data->source = qio_task_get_source(task);
+    qio_task_propagate_error(task, &data->err);
 
     data->complete = g_thread_self();
 
diff --git a/ui/vnc-auth-vencrypt.c b/ui/vnc-auth-vencrypt.c
index c0c29a5..ffaab57 100644
--- a/ui/vnc-auth-vencrypt.c
+++ b/ui/vnc-auth-vencrypt.c
@@ -65,16 +65,17 @@ static void start_auth_vencrypt_subauth(VncState *vs)
     }
 }
 
-static void vnc_tls_handshake_done(Object *source,
-                                   Error *err,
+static void vnc_tls_handshake_done(QIOTask *task,
                                    gpointer user_data)
 {
     VncState *vs = user_data;
+    Error *err = NULL;
 
-    if (err) {
+    if (qio_task_propagate_error(task, &err)) {
         VNC_DEBUG("Handshake failed %s\n",
                   error_get_pretty(err));
         vnc_client_error(vs);
+        error_free(err);
     } else {
         vs->ioc_tag = qio_channel_add_watch(
             vs->ioc, G_IO_IN | G_IO_OUT, vnc_client_io, vs, NULL);
diff --git a/ui/vnc-ws.c b/ui/vnc-ws.c
index bffb484..f530cd5 100644
--- a/ui/vnc-ws.c
+++ b/ui/vnc-ws.c
@@ -24,15 +24,16 @@
 #include "io/channel-websock.h"
 #include "qemu/bswap.h"
 
-static void vncws_tls_handshake_done(Object *source,
-                                     Error *err,
+static void vncws_tls_handshake_done(QIOTask *task,
                                      gpointer user_data)
 {
     VncState *vs = user_data;
+    Error *err = NULL;
 
-    if (err) {
+    if (qio_task_propagate_error(task, &err)) {
         VNC_DEBUG("Handshake failed %s\n", error_get_pretty(err));
         vnc_client_error(vs);
+        error_free(err);
     } else {
         VNC_DEBUG("TLS handshake complete, starting websocket handshake\n");
         vs->ioc_tag = qio_channel_add_watch(
@@ -83,15 +84,16 @@ gboolean vncws_tls_handshake_io(QIOChannel *ioc G_GNUC_UNUSED,
 }
 
 
-static void vncws_handshake_done(Object *source,
-                                 Error *err,
+static void vncws_handshake_done(QIOTask *task,
                                  gpointer user_data)
 {
     VncState *vs = user_data;
+    Error *err = NULL;
 
-    if (err) {
+    if (qio_task_propagate_error(task, &err)) {
         VNC_DEBUG("Websock handshake failed %s\n", error_get_pretty(err));
         vnc_client_error(vs);
+        error_free(err);
     } else {
         VNC_DEBUG("Websock handshake complete, starting VNC protocol\n");
         vnc_start_protocol(vs);
-- 
2.9.3

[Qemu-devel] [PULL v2 7/8] io: remove Error parameter from QIOTask thread worker

[Daniel P. Berrange]

Now that task objects have a directly associated error,
there's no need for an an Error **errp parameter to
the QIOTask thread worker function. It already has a
QIOTask object, so can directly set the error on it.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/io/task.h    | 19 ++++++++-----------
 io/channel-socket.c  | 41 ++++++++++++++++-------------------------
 io/task.c            | 10 +---------
 tests/test-io-task.c | 12 +++++-------
 4 files changed, 30 insertions(+), 52 deletions(-)

diff --git a/include/io/task.h b/include/io/task.h
index ad90970..6021f51 100644
--- a/include/io/task.h
+++ b/include/io/task.h
@@ -29,9 +29,8 @@ typedef struct QIOTask QIOTask;
 typedef void (*QIOTaskFunc)(QIOTask *task,
                             gpointer opaque);
 
-typedef int (*QIOTaskWorker)(QIOTask *task,
-                             Error **errp,
-                             gpointer opaque);
+typedef void (*QIOTaskWorker)(QIOTask *task,
+                              gpointer opaque);
 
 /**
  * QIOTask:
@@ -163,18 +162,16 @@ typedef int (*QIOTaskWorker)(QIOTask *task,
  * socket listen using QIOTask would require:
  *
  * <example>
- *    static int myobject_listen_worker(QIOTask *task,
- *                                      Error **errp,
- *                                      gpointer opaque)
+ *    static void myobject_listen_worker(QIOTask *task,
+ *                                       gpointer opaque)
  *    {
  *       QMyObject obj = QMY_OBJECT(qio_task_get_source(task));
  *       SocketAddress *addr = opaque;
+ *       Error *err = NULL;
  *
- *       obj->fd = socket_listen(addr, errp);
- *       if (obj->fd < 0) {
- *          return -1;
- *       }
- *       return 0;
+ *       obj->fd = socket_listen(addr, &err);
+ *
+         qio_task_set_error(task, err);
  *    }
  *
  *    void myobject_listen_async(QMyObject *obj,
diff --git a/io/channel-socket.c b/io/channel-socket.c
index 45df819..f385233 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -156,19 +156,16 @@ int qio_channel_socket_connect_sync(QIOChannelSocket *ioc,
 }
 
 
-static int qio_channel_socket_connect_worker(QIOTask *task,
-                                             Error **errp,
-                                             gpointer opaque)
+static void qio_channel_socket_connect_worker(QIOTask *task,
+                                              gpointer opaque)
 {
     QIOChannelSocket *ioc = QIO_CHANNEL_SOCKET(qio_task_get_source(task));
     SocketAddress *addr = opaque;
-    int ret;
+    Error *err = NULL;
 
-    ret = qio_channel_socket_connect_sync(ioc,
-                                          addr,
-                                          errp);
+    qio_channel_socket_connect_sync(ioc, addr, &err);
 
-    return ret;
+    qio_task_set_error(task, err);
 }
 
 
@@ -218,19 +215,16 @@ int qio_channel_socket_listen_sync(QIOChannelSocket *ioc,
 }
 
 
-static int qio_channel_socket_listen_worker(QIOTask *task,
-                                            Error **errp,
-                                            gpointer opaque)
+static void qio_channel_socket_listen_worker(QIOTask *task,
+                                             gpointer opaque)
 {
     QIOChannelSocket *ioc = QIO_CHANNEL_SOCKET(qio_task_get_source(task));
     SocketAddress *addr = opaque;
-    int ret;
+    Error *err = NULL;
 
-    ret = qio_channel_socket_listen_sync(ioc,
-                                         addr,
-                                         errp);
+    qio_channel_socket_listen_sync(ioc, addr, &err);
 
-    return ret;
+    qio_task_set_error(task, err);
 }
 
 
@@ -293,21 +287,18 @@ static void qio_channel_socket_dgram_worker_free(gpointer opaque)
     g_free(data);
 }
 
-static int qio_channel_socket_dgram_worker(QIOTask *task,
-                                           Error **errp,
-                                           gpointer opaque)
+static void qio_channel_socket_dgram_worker(QIOTask *task,
+                                            gpointer opaque)
 {
     QIOChannelSocket *ioc = QIO_CHANNEL_SOCKET(qio_task_get_source(task));
     struct QIOChannelSocketDGramWorkerData *data = opaque;
-    int ret;
+    Error *err = NULL;
 
     /* socket_dgram() blocks in DNS lookups, so we must use a thread */
-    ret = qio_channel_socket_dgram_sync(ioc,
-                                        data->localAddr,
-                                        data->remoteAddr,
-                                        errp);
+    qio_channel_socket_dgram_sync(ioc, data->localAddr,
+                                  data->remoteAddr, &err);
 
-    return ret;
+    qio_task_set_error(task, err);
 }
 
 
diff --git a/io/task.c b/io/task.c
index 42e1a75..60bf1a9 100644
--- a/io/task.c
+++ b/io/task.c
@@ -77,8 +77,6 @@ struct QIOTaskThreadData {
     QIOTaskWorker worker;
     gpointer opaque;
     GDestroyNotify destroy;
-    Error *err;
-    int ret;
 };
 
 
@@ -87,9 +85,6 @@ static gboolean gio_task_thread_result(gpointer opaque)
     struct QIOTaskThreadData *data = opaque;
 
     trace_qio_task_thread_result(data->task);
-    if (data->err) {
-        qio_task_set_error(data->task, data->err);
-    }
     qio_task_complete(data->task);
 
     if (data->destroy) {
@@ -107,10 +102,7 @@ static gpointer qio_task_thread_worker(gpointer opaque)
     struct QIOTaskThreadData *data = opaque;
 
     trace_qio_task_thread_run(data->task);
-    data->ret = data->worker(data->task, &data->err, data->opaque);
-    if (data->ret < 0 && data->err == NULL) {
-        error_setg(&data->err, "Task worker failed but did not set an error");
-    }
+    data->worker(data->task, data->opaque);
 
     /* We're running in the background thread, and must only
      * ever report the task results in the main event loop
diff --git a/tests/test-io-task.c b/tests/test-io-task.c
index 84144c9..ff62272 100644
--- a/tests/test-io-task.c
+++ b/tests/test-io-task.c
@@ -140,20 +140,18 @@ struct TestThreadWorkerData {
     GMainLoop *loop;
 };
 
-static int test_task_thread_worker(QIOTask *task,
-                                   Error **errp,
-                                   gpointer opaque)
+static void test_task_thread_worker(QIOTask *task,
+                                    gpointer opaque)
 {
     struct TestThreadWorkerData *data = opaque;
 
     data->worker = g_thread_self();
 
     if (data->fail) {
-        error_setg(errp, "Testing fail");
-        return -1;
+        Error *err = NULL;
+        error_setg(&err, "Testing fail");
+        qio_task_set_error(task, err);
     }
-
-    return 0;
 }
 
 
-- 
2.9.3

[Qemu-devel] [PULL v2 8/8] io: introduce a DNS resolver API

[Daniel P. Berrange]

Currently DNS resolution is done automatically as part
of the creation of a QIOChannelSocket object instance.
This works ok for network clients where you just end
up a single network socket, but for servers, the results
of DNS resolution may require creation of multiple
sockets.

Introducing a DNS resolver API allows DNS resolution
to be separated from the socket object creation. This
will make it practical to create multiple QIOChannelSocket
instances for servers.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/io/dns-resolver.h | 228 ++++++++++++++++++++++++++++++++++++++
 include/qemu/sockets.h    |   2 +
 io/Makefile.objs          |   1 +
 io/dns-resolver.c         | 276 ++++++++++++++++++++++++++++++++++++++++++++++
 util/qemu-sockets.c       |   4 +-
 5 files changed, 509 insertions(+), 2 deletions(-)
 create mode 100644 include/io/dns-resolver.h
 create mode 100644 io/dns-resolver.c

diff --git a/include/io/dns-resolver.h b/include/io/dns-resolver.h
new file mode 100644
index 0000000..2f69c08
--- /dev/null
+++ b/include/io/dns-resolver.h
@@ -0,0 +1,228 @@
+/*
+ * QEMU DNS resolver
+ *
+ * Copyright (c) 2016-2017 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef QIO_DNS_RESOLVER_H
+#define QIO_DNS_RESOLVER_H
+
+#include "qemu-common.h"
+#include "qom/object.h"
+#include "io/task.h"
+
+#define TYPE_QIO_DNS_RESOLVER "qio-dns-resolver"
+#define QIO_DNS_RESOLVER(obj)                                    \
+    OBJECT_CHECK(QIODNSResolver, (obj), TYPE_QIO_DNS_RESOLVER)
+#define QIO_DNS_RESOLVER_CLASS(klass)                                    \
+    OBJECT_CLASS_CHECK(QIODNSResolverClass, klass, TYPE_QIO_DNS_RESOLVER)
+#define QIO_DNS_RESOLVER_GET_CLASS(obj)                                  \
+    OBJECT_GET_CLASS(QIODNSResolverClass, obj, TYPE_QIO_DNS_RESOLVER)
+
+typedef struct QIODNSResolver QIODNSResolver;
+typedef struct QIODNSResolverClass QIODNSResolverClass;
+
+/**
+ * QIODNSResolver:
+ *
+ * The QIODNSResolver class provides a framework for doing
+ * DNS resolution on SocketAddress objects, independently
+ * of socket creation.
+ *
+ * <example>
+ *   <title>Resolving addresses synchronously</title>
+ *   <programlisting>
+ *    int mylisten(SocketAddress *addr, Error **errp) {
+ *      QIODNSResolver *resolver = qio_dns_resolver_get_instance();
+ *      SocketAddress **rawaddrs = NULL;
+ *      size_t nrawaddrs = 0;
+ *      Error *err = NULL;
+ *      QIOChannel **socks = NULL;
+ *      size_t nsocks = 0;
+ *
+ *      if (qio_dns_resolver_lookup_sync(dns, addr, &nrawaddrs,
+ *                                       &rawaddrs, errp) < 0) {
+ *          return -1;
+ *      }
+ *
+ *      for (i = 0; i < nrawaddrs; i++) {
+ *         QIOChannel *sock = qio_channel_new();
+ *         Error *local_err = NULL;
+ *         qio_channel_listen_sync(sock, rawaddrs[i], &local_err);
+ *         if (local_err) {
+ *            error_propagate(&err, local_err);
+ *         } else {
+ *            socks = g_renew(QIOChannelSocket *, socks, nsocks + 1);
+ *            socks[nsocks++] = sock;
+ *         }
+ *         qapi_free_SocketAddress(rawaddrs[i]);
+ *      }
+ *      g_free(rawaddrs);
+ *
+ *      if (nsocks == 0) {
+ *         error_propagate(errp, err);
+ *      } else {
+ *         error_free(err);
+ *      }
+ *   }
+ *   </programlisting>
+ * </example>
+ *
+ * <example>
+ *   <title>Resolving addresses asynchronously</title>
+ *   <programlisting>
+ *    typedef struct MyListenData {
+ *       Error *err;
+ *       QIOChannelSocket **socks;
+ *       size_t nsocks;
+ *    } MyListenData;
+ *
+ *    void mylistenresult(QIOTask *task, void *opaque) {
+ *      MyListenData *data = opaque;
+ *      QIODNSResolver *resolver =
+ *         QIO_DNS_RESOLVER(qio_task_get_source(task);
+ *      SocketAddress **rawaddrs = NULL;
+ *      size_t nrawaddrs = 0;
+ *      Error *err = NULL;
+ *
+ *      if (qio_task_propagate_error(task, &data->err)) {
+ *         return;
+ *      }
+ *
+ *      qio_dns_resolver_lookup_result(resolver, task,
+ *                                     &nrawaddrs, &rawaddrs);
+ *
+ *      for (i = 0; i < nrawaddrs; i++) {
+ *         QIOChannel *sock = qio_channel_new();
+ *         Error *local_err = NULL;
+ *         qio_channel_listen_sync(sock, rawaddrs[i], &local_err);
+ *         if (local_err) {
+ *            error_propagate(&err, local_err);
+ *         } else {
+ *            socks = g_renew(QIOChannelSocket *, socks, nsocks + 1);
+ *            socks[nsocks++] = sock;
+ *         }
+ *         qapi_free_SocketAddress(rawaddrs[i]);
+ *      }
+ *      g_free(rawaddrs);
+ *
+ *      if (nsocks == 0) {
+ *         error_propagate(&data->err, err);
+ *      } else {
+ *         error_free(err);
+ *      }
+ *    }
+ *
+ *    void mylisten(SocketAddress *addr, MyListenData *data) {
+ *      QIODNSResolver *resolver = qio_dns_resolver_get_instance();
+ *      qio_dns_resolver_lookup_async(dns, addr,
+ *                                    mylistenresult, data, NULL);
+ *    }
+ *   </programlisting>
+ * </example>
+ */
+struct QIODNSResolver {
+    Object parent;
+};
+
+struct QIODNSResolverClass {
+    ObjectClass parent;
+};
+
+
+/**
+ * qio_dns_resolver_get_instance:
+ *
+ * Get the singleton dns resolver instance. The caller
+ * does not own a reference on the returned object.
+ *
+ * Returns: the single dns resolver instance
+ */
+QIODNSResolver *qio_dns_resolver_get_instance(void);
+
+/**
+ * qio_dns_resolver_lookup_sync:
+ * @resolver: the DNS resolver instance
+ * @addr: the address to resolve
+ * @naddr: pointer to hold number of resolved addresses
+ * @addrs: pointer to hold resolved addresses
+ * @errp: pointer to NULL initialized error object
+ *
+ * This will attempt to resolve the address provided
+ * in @addr. If resolution succeeds, @addrs will be filled
+ * with all the resolved addresses. @naddrs will specify
+ * the number of entries allocated in @addrs. The caller
+ * is responsible for freeing each entry in @addrs, as
+ * well as @addrs itself. @naddrs is guaranteed to be
+ * greater than zero on success.
+ *
+ * DNS resolution will be done synchronously so execution
+ * of the caller may be blocked for an arbitrary length
+ * of time.
+ *
+ * Returns: 0 if resolution was successful, -1 on error
+ */
+int qio_dns_resolver_lookup_sync(QIODNSResolver *resolver,
+                                 SocketAddress *addr,
+                                 size_t *naddrs,
+                                 SocketAddress ***addrs,
+                                 Error **errp);
+
+/**
+ * qio_dns_resolver_lookup_async:
+ * @resolver: the DNS resolver instance
+ * @addr: the address to resolve
+ * @func: the callback to invoke on lookup completion
+ * @opaque: data blob to pass to @func
+ * @notify: the callback to free @opaque, or NULL
+ *
+ * This will attempt to resolve the address provided
+ * in @addr. The callback @func will be invoked when
+ * resolution has either completed or failed. On
+ * success, the @func should call the method
+ * qio_dns_resolver_lookup_result() to obtain the
+ * results.
+ *
+ * DNS resolution will be done asynchronously so execution
+ * of the caller will not be blocked.
+ */
+void qio_dns_resolver_lookup_async(QIODNSResolver *resolver,
+                                   SocketAddress *addr,
+                                   QIOTaskFunc func,
+                                   gpointer opaque,
+                                   GDestroyNotify notify);
+
+/**
+ * qio_dns_resolver_lookup_result:
+ * @resolver: the DNS resolver instance
+ * @task: the task object to get results for
+ * @naddr: pointer to hold number of resolved addresses
+ * @addrs: pointer to hold resolved addresses
+ *
+ * This method should be called from the callback passed
+ * to qio_dns_resolver_lookup_async() in order to obtain
+ * results.  @addrs will be filled with all the resolved
+ * addresses. @naddrs will specify the number of entries
+ * allocated in @addrs. The caller is responsible for
+ * freeing each entry in @addrs, as well as @addrs itself.
+ */
+void qio_dns_resolver_lookup_result(QIODNSResolver *resolver,
+                                    QIOTask *task,
+                                    size_t *naddrs,
+                                    SocketAddress ***addrs);
+
+#endif /* QIO_DNS_RESOLVER_H */
diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
index 5589e68..5f1bab9 100644
--- a/include/qemu/sockets.h
+++ b/include/qemu/sockets.h
@@ -32,6 +32,8 @@ int socket_set_fast_reuse(int fd);
  */
 typedef void NonBlockingConnectHandler(int fd, Error *err, void *opaque);
 
+int inet_ai_family_from_address(InetSocketAddress *addr,
+                                Error **errp);
 InetSocketAddress *inet_parse(const char *str, Error **errp);
 int inet_connect(const char *str, Error **errp);
 int inet_connect_saddr(InetSocketAddress *saddr, Error **errp,
diff --git a/io/Makefile.objs b/io/Makefile.objs
index 9d8337d..12983cc 100644
--- a/io/Makefile.objs
+++ b/io/Makefile.objs
@@ -7,4 +7,5 @@ io-obj-y += channel-tls.o
 io-obj-y += channel-watch.o
 io-obj-y += channel-websock.o
 io-obj-y += channel-util.o
+io-obj-y += dns-resolver.o
 io-obj-y += task.o
diff --git a/io/dns-resolver.c b/io/dns-resolver.c
new file mode 100644
index 0000000..0ac6b23
--- /dev/null
+++ b/io/dns-resolver.c
@@ -0,0 +1,276 @@
+/*
+ * QEMU DNS resolver
+ *
+ * Copyright (c) 2016 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "io/dns-resolver.h"
+#include "qapi/clone-visitor.h"
+#include "qemu/sockets.h"
+#include "qapi/error.h"
+#include "qemu/cutils.h"
+
+#ifndef AI_NUMERICSERV
+# define AI_NUMERICSERV 0
+#endif
+
+static QIODNSResolver *instance;
+static GOnce instance_init = G_ONCE_INIT;
+
+static gpointer qio_dns_resolve_init_instance(gpointer unused G_GNUC_UNUSED)
+{
+    instance = QIO_DNS_RESOLVER(object_new(TYPE_QIO_DNS_RESOLVER));
+    return NULL;
+}
+
+QIODNSResolver *qio_dns_resolver_get_instance(void)
+{
+    g_once(&instance_init, qio_dns_resolve_init_instance, NULL);
+    return instance;
+}
+
+static int qio_dns_resolver_lookup_sync_inet(QIODNSResolver *resolver,
+                                             SocketAddress *addr,
+                                             size_t *naddrs,
+                                             SocketAddress ***addrs,
+                                             Error **errp)
+{
+    struct addrinfo ai, *res, *e;
+    InetSocketAddress *iaddr = addr->u.inet.data;
+    char port[33];
+    char uaddr[INET6_ADDRSTRLEN + 1];
+    char uport[33];
+    int rc;
+    Error *err = NULL;
+    size_t i;
+
+    *naddrs = 0;
+    *addrs = NULL;
+
+    memset(&ai, 0, sizeof(ai));
+    ai.ai_flags = AI_PASSIVE;
+    if (iaddr->has_numeric && iaddr->numeric) {
+        ai.ai_flags |= AI_NUMERICHOST | AI_NUMERICSERV;
+    }
+    ai.ai_family = inet_ai_family_from_address(iaddr, &err);
+    ai.ai_socktype = SOCK_STREAM;
+
+    if (err) {
+        error_propagate(errp, err);
+        return -1;
+    }
+
+    if (iaddr->host == NULL) {
+        error_setg(errp, "host not specified");
+        return -1;
+    }
+    if (iaddr->port != NULL) {
+        pstrcpy(port, sizeof(port), iaddr->port);
+    } else {
+        port[0] = '\0';
+    }
+
+    rc = getaddrinfo(strlen(iaddr->host) ? iaddr->host : NULL,
+                     strlen(port) ? port : NULL, &ai, &res);
+    if (rc != 0) {
+        error_setg(errp, "address resolution failed for %s:%s: %s",
+                   iaddr->host, port, gai_strerror(rc));
+        return -1;
+    }
+
+    for (e = res; e != NULL; e = e->ai_next) {
+        (*naddrs)++;
+    }
+
+    *addrs = g_new0(SocketAddress *, *naddrs);
+
+    /* create socket + bind */
+    for (i = 0, e = res; e != NULL; i++, e = e->ai_next) {
+        SocketAddress *newaddr = g_new0(SocketAddress, 1);
+        InetSocketAddress *newiaddr = g_new0(InetSocketAddress, 1);
+        newaddr->u.inet.data = newiaddr;
+        newaddr->type = SOCKET_ADDRESS_KIND_INET;
+
+        getnameinfo((struct sockaddr *)e->ai_addr, e->ai_addrlen,
+                    uaddr, INET6_ADDRSTRLEN, uport, 32,
+                    NI_NUMERICHOST | NI_NUMERICSERV);
+
+        *newiaddr = (InetSocketAddress){
+            .host = g_strdup(uaddr),
+            .port = g_strdup(uport),
+            .has_numeric = true,
+            .numeric = true,
+            .has_to = iaddr->has_to,
+            .to = iaddr->to,
+            .has_ipv4 = false,
+            .has_ipv6 = false,
+        };
+
+        (*addrs)[i] = newaddr;
+    }
+    freeaddrinfo(res);
+    return 0;
+}
+
+
+static int qio_dns_resolver_lookup_sync_nop(QIODNSResolver *resolver,
+                                            SocketAddress *addr,
+                                            size_t *naddrs,
+                                            SocketAddress ***addrs,
+                                            Error **errp)
+{
+    *naddrs = 1;
+    *addrs = g_new0(SocketAddress *, 1);
+    (*addrs)[0] = QAPI_CLONE(SocketAddress, addr);
+
+    return 0;
+}
+
+
+int qio_dns_resolver_lookup_sync(QIODNSResolver *resolver,
+                                 SocketAddress *addr,
+                                 size_t *naddrs,
+                                 SocketAddress ***addrs,
+                                 Error **errp)
+{
+    switch (addr->type) {
+    case SOCKET_ADDRESS_KIND_INET:
+        return qio_dns_resolver_lookup_sync_inet(resolver,
+                                                 addr,
+                                                 naddrs,
+                                                 addrs,
+                                                 errp);
+
+    case SOCKET_ADDRESS_KIND_UNIX:
+    case SOCKET_ADDRESS_KIND_VSOCK:
+        return qio_dns_resolver_lookup_sync_nop(resolver,
+                                                addr,
+                                                naddrs,
+                                                addrs,
+                                                errp);
+
+    default:
+        error_setg(errp, "Unknown socket address kind");
+        return -1;
+    }
+}
+
+
+struct QIODNSResolverLookupData {
+    SocketAddress *addr;
+    SocketAddress **addrs;
+    size_t naddrs;
+};
+
+
+static void qio_dns_resolver_lookup_data_free(gpointer opaque)
+{
+    struct QIODNSResolverLookupData *data = opaque;
+    size_t i;
+
+    qapi_free_SocketAddress(data->addr);
+    for (i = 0; i < data->naddrs; i++) {
+        qapi_free_SocketAddress(data->addrs[i]);
+    }
+
+    g_free(data->addrs);
+    g_free(data);
+}
+
+
+static void qio_dns_resolver_lookup_worker(QIOTask *task,
+                                           gpointer opaque)
+{
+    QIODNSResolver *resolver = QIO_DNS_RESOLVER(qio_task_get_source(task));
+    struct QIODNSResolverLookupData *data = opaque;
+    Error *err = NULL;
+
+    qio_dns_resolver_lookup_sync(resolver,
+                                 data->addr,
+                                 &data->naddrs,
+                                 &data->addrs,
+                                 &err);
+    if (err) {
+        qio_task_set_error(task, err);
+    } else {
+        qio_task_set_result_pointer(task, opaque, NULL);
+    }
+
+    object_unref(OBJECT(resolver));
+}
+
+
+void qio_dns_resolver_lookup_async(QIODNSResolver *resolver,
+                                   SocketAddress *addr,
+                                   QIOTaskFunc func,
+                                   gpointer opaque,
+                                   GDestroyNotify notify)
+{
+    QIOTask *task;
+    struct QIODNSResolverLookupData *data =
+        g_new0(struct QIODNSResolverLookupData, 1);
+
+    data->addr = QAPI_CLONE(SocketAddress, addr);
+
+    task = qio_task_new(OBJECT(resolver), func, opaque, notify);
+
+    qio_task_run_in_thread(task,
+                           qio_dns_resolver_lookup_worker,
+                           data,
+                           qio_dns_resolver_lookup_data_free);
+}
+
+
+void qio_dns_resolver_lookup_result(QIODNSResolver *resolver,
+                                    QIOTask *task,
+                                    size_t *naddrs,
+                                    SocketAddress ***addrs)
+{
+    struct QIODNSResolverLookupData *data =
+        qio_task_get_result_pointer(task);
+    size_t i;
+
+    *naddrs = 0;
+    *addrs = NULL;
+    if (!data) {
+        return;
+    }
+
+    *naddrs = data->naddrs;
+    *addrs = g_new0(SocketAddress *, data->naddrs);
+    for (i = 0; i < data->naddrs; i++) {
+        (*addrs)[i] = QAPI_CLONE(SocketAddress, data->addrs[i]);
+    }
+}
+
+
+static const TypeInfo qio_dns_resolver_info = {
+    .parent = TYPE_OBJECT,
+    .name = TYPE_QIO_DNS_RESOLVER,
+    .instance_size = sizeof(QIODNSResolver),
+    .class_size = sizeof(QIODNSResolverClass),
+};
+
+
+static void qio_dns_resolver_register_types(void)
+{
+    type_register_static(&qio_dns_resolver_info);
+}
+
+
+type_init(qio_dns_resolver_register_types);
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index b6d99cb..7c120c4 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -114,8 +114,8 @@ NetworkAddressFamily inet_netfamily(int family)
  * outside scope of this method and not currently handled by
  * callers at all.
  */
-static int inet_ai_family_from_address(InetSocketAddress *addr,
-                                       Error **errp)
+int inet_ai_family_from_address(InetSocketAddress *addr,
+                                Error **errp)
 {
     if (addr->has_ipv6 && addr->has_ipv4 &&
         !addr->ipv6 && !addr->ipv4) {
-- 
2.9.3

Re: [Qemu-devel] [PULL v2 0/8] Merge io/ 2017-01-23

[Peter Maydell]

On 23 January 2017 at 15:57, Daniel P. Berrange <berrange@redhat.com> wrote:
> The following changes since commit 598cf1c805271564686f2d732b36f50c3c40dcdd:
>
>   Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging (2017-01-20 16:42:07 +0000)
>
> are available in the git repository at:
>
>   git://github.com/berrange/qemu tags/pull-qio-2017-01-23-2
>
> for you to fetch changes up to c1b412f1d94ba717896f876dbf59fffa91e596fc:
>
>   io: introduce a DNS resolver API (2017-01-23 15:32:46 +0000)
>
> ----------------------------------------------------------------
> Merge io/ 2017-01-23
>
> ----------------------------------------------------------------
>
> Daniel P. Berrange (8):
>   sockets: add ability to disable DNS resolution for InetSocketAddress
>   io: stop incrementing reference in qio_task_get_source
>   io: fix typo in docs for QIOTask
>   io: add ability to associate an opaque "result" with with a task
>   io: add ability to associate an error with a task
>   io: change the QIOTask callback signature
>   io: remove Error parameter from QIOTask thread worker
>   io: introduce a DNS resolver API

Applied, thanks.

-- PMM