[Qemu-devel] [PATCH v2 05/15] nbd: convert blockdev NBD server to use I/O channels for connection setup

["Daniel P. Berrange" <berrange@redhat.com>]

This converts the blockdev NBD server to use the QIOChannelSocket
class for initial listener socket setup and accepting of client
connections. Actual I/O is still being performed against the
socket file descriptor using the POSIX socket APIs.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 blockdev-nbd.c | 53 ++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index bcdd18b..71ee021 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -17,33 +17,49 @@
 #include "qmp-commands.h"
 #include "trace.h"
 #include "block/nbd.h"
-#include "qemu/sockets.h"
+#include "io/channel-socket.h"
 
-static int server_fd = -1;
+static QIOChannelSocket *server_ioc;
+static int server_watch = -1;
 
-static void nbd_accept(void *opaque)
+static gboolean nbd_accept(QIOChannel *ioc, GIOCondition condition,
+                           gpointer opaque)
 {
-    struct sockaddr_in addr;
-    socklen_t addr_len = sizeof(addr);
+    QIOChannelSocket *cioc;
+    int fd;
 
-    int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
-    if (fd >= 0 && !nbd_client_new(NULL, fd, nbd_client_put)) {
-        shutdown(fd, 2);
+    cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
+                                     NULL);
+    if (!cioc) {
+        return TRUE;
+    }
+
+    fd = dup(cioc->fd);
+    if (fd >= 0 &&
+        !nbd_client_new(NULL, fd, nbd_client_put)) {
         close(fd);
     }
+    object_unref(OBJECT(cioc));
+    return TRUE;
 }
 
 void qmp_nbd_server_start(SocketAddress *addr, Error **errp)
 {
-    if (server_fd != -1) {
+    if (server_ioc) {
         error_setg(errp, "NBD server already running");
         return;
     }
 
-    server_fd = socket_listen(addr, errp);
-    if (server_fd != -1) {
-        qemu_set_fd_handler(server_fd, nbd_accept, NULL, NULL);
+    server_ioc = qio_channel_socket_new();
+    if (qio_channel_socket_listen_sync(server_ioc, addr, errp) < 0) {
+        return;
     }
+
+    server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
+                                         G_IO_IN,
+                                         nbd_accept,
+                                         NULL,
+                                         NULL);
 }
 
 /*
@@ -78,7 +94,7 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
     NBDExport *exp;
     NBDCloseNotifier *n;
 
-    if (server_fd == -1) {
+    if (!server_ioc) {
         error_setg(errp, "NBD server not running");
         return;
     }
@@ -128,9 +144,12 @@ void qmp_nbd_server_stop(Error **errp)
         nbd_close_notifier(&cn->n, nbd_export_get_blockdev(cn->exp));
     }
 
-    if (server_fd != -1) {
-        qemu_set_fd_handler(server_fd, NULL, NULL, NULL);
-        close(server_fd);
-        server_fd = -1;
+    if (server_watch != -1) {
+        g_source_remove(server_watch);
+        server_watch = -1;
+    }
+    if (server_ioc) {
+        object_unref(OBJECT(server_ioc));
+        server_ioc = NULL;
     }
 }
-- 
2.5.0