migration: convert unix socket protocol to use QIOChannel

Convert the unix socket migration protocol driver to use
QIOChannel and QEMUFileChannel, instead of plain sockets
APIs. It can be unconditionally built, since the socket
impl of QIOChannel will report a suitable error on platforms
where UNIX sockets are unavailable.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1461751518-12128-13-git-send-email-berrange@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>

migration/Makefile.objs

@@ -1,4 +1,4 @@
-common-obj-y += migration.o tcp.o
+common-obj-y += migration.o tcp.o unix.o
 common-obj-y += vmstate.o
 common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o qemu-file-stdio.o
 common-obj-y += qemu-file-channel.o
@@ -6,7 +6,7 @@ common-obj-y += xbzrle.o postcopy-ram.o
 common-obj-y += qjson.o
 
 common-obj-$(CONFIG_RDMA) += rdma.o
-common-obj-$(CONFIG_POSIX) += exec.o unix.o fd.o
+common-obj-$(CONFIG_POSIX) += exec.o fd.o
 
 common-obj-y += block.o
 

migration/migration.c

@@ -314,8 +314,10 @@ void qemu_start_incoming_migration(const char *uri, Error **errp)
 #if !defined(WIN32)
     } else if (strstart(uri, "exec:", &p)) {
         exec_start_incoming_migration(p, errp);
+#endif
     } else if (strstart(uri, "unix:", &p)) {
         unix_start_incoming_migration(p, errp);
+#if !defined(WIN32)
     } else if (strstart(uri, "fd:", &p)) {
         fd_start_incoming_migration(p, errp);
 #endif
@@ -1072,8 +1074,10 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
 #if !defined(WIN32)
     } else if (strstart(uri, "exec:", &p)) {
         exec_start_outgoing_migration(s, p, &local_err);
+#endif
     } else if (strstart(uri, "unix:", &p)) {
         unix_start_outgoing_migration(s, p, &local_err);
+#if !defined(WIN32)
     } else if (strstart(uri, "fd:", &p)) {
         fd_start_outgoing_migration(s, p, &local_err);
 #endif

migration/unix.c

@@ -1,10 +1,11 @@
 /*
  * QEMU live migration via Unix Domain Sockets
  *
- * Copyright Red Hat, Inc. 2009
+ * Copyright Red Hat, Inc. 2009-2016
  *
  * Authors:
  *  Chris Lalancette <clalance@redhat.com>
+ *  Daniel P. Berrange <berrange@redhat.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2.  See
  * the COPYING file in the top-level directory.
@@ -17,87 +18,104 @@
 
 #include "qemu-common.h"
 #include "qemu/error-report.h"
-#include "qemu/sockets.h"
+#include "qapi/error.h"
-#include "qemu/main-loop.h"
 #include "migration/migration.h"
 #include "migration/qemu-file.h"
-#include "block/block.h"
+#include "io/channel-socket.h"
+#include "trace.h"
 
-//#define DEBUG_MIGRATION_UNIX
 
-#ifdef DEBUG_MIGRATION_UNIX
+static SocketAddress *unix_build_address(const char *path)
-#define DPRINTF(fmt, ...) \
+{
-    do { printf("migration-unix: " fmt, ## __VA_ARGS__); } while (0)
+    SocketAddress *saddr;
-#else
-#define DPRINTF(fmt, ...) \
-    do { } while (0)
-#endif
 
-static void unix_wait_for_connect(int fd, Error *err, void *opaque)
+    saddr = g_new0(SocketAddress, 1);
+    saddr->type = SOCKET_ADDRESS_KIND_UNIX;
+    saddr->u.q_unix.data = g_new0(UnixSocketAddress, 1);
+    saddr->u.q_unix.data->path = g_strdup(path);
+
+    return saddr;
+}
+
+
+static void unix_outgoing_migration(Object *src,
+                                    Error *err,
+                                    gpointer opaque)
 {
     MigrationState *s = opaque;
+    QIOChannel *sioc = QIO_CHANNEL(src);
 
-    if (fd < 0) {
+    if (err) {
-        DPRINTF("migrate connect error: %s\n", error_get_pretty(err));
+        trace_migration_unix_outgoing_error(error_get_pretty(err));
         s->to_dst_file = NULL;
         migrate_fd_error(s, err);
     } else {
-        DPRINTF("migrate connect success\n");
+        trace_migration_unix_outgoing_connected();
-        s->to_dst_file = qemu_fopen_socket(fd, "wb");
+        migration_set_outgoing_channel(s, sioc);
-        migrate_fd_connect(s);
     }
+    object_unref(src);
 }
 
+
 void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp)
 {
-    unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
+    SocketAddress *saddr = unix_build_address(path);
+    QIOChannelSocket *sioc;
+    sioc = qio_channel_socket_new();
+    qio_channel_socket_connect_async(sioc,
+                                     saddr,
+                                     unix_outgoing_migration,
+                                     s,
+                                     NULL);
+    qapi_free_SocketAddress(saddr);
 }
 
-static void unix_accept_incoming_migration(void *opaque)
+
+static gboolean unix_accept_incoming_migration(QIOChannel *ioc,
+                                               GIOCondition condition,
+                                               gpointer opaque)
 {
-    struct sockaddr_un addr;
+    QIOChannelSocket *sioc;
-    socklen_t addrlen = sizeof(addr);
+    Error *err = NULL;
-    int s = (intptr_t)opaque;
-    QEMUFile *f;
-    int c, err;
 
-    do {
+    sioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
-        c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
+                                     &err);
-        err = errno;
+    if (!sioc) {
-    } while (c < 0 && err == EINTR);
-    qemu_set_fd_handler(s, NULL, NULL, NULL);
-    close(s);
-
-    DPRINTF("accepted migration\n");
-
-    if (c < 0) {
         error_report("could not accept migration connection (%s)",
-                     strerror(err));
+                     error_get_pretty(err));
-        return;
-    }
-
-    f = qemu_fopen_socket(c, "rb");
-    if (f == NULL) {
-        error_report("could not qemu_fopen socket");
         goto out;
     }
 
-    process_incoming_migration(f);
+    trace_migration_unix_incoming_accepted();
-    return;
+
+    migration_set_incoming_channel(migrate_get_current(),
+                                   QIO_CHANNEL(sioc));
+    object_unref(OBJECT(sioc));
 
 out:
-    close(c);
+    /* Close listening socket as its no longer needed */
+    qio_channel_close(ioc, NULL);
+    return FALSE; /* unregister */
 }
 
+
 void unix_start_incoming_migration(const char *path, Error **errp)
 {
-    int s;
+    SocketAddress *saddr = unix_build_address(path);
+    QIOChannelSocket *listen_ioc;
 
-    s = unix_listen(path, NULL, 0, errp);
+    listen_ioc = qio_channel_socket_new();
-    if (s < 0) {
+    if (qio_channel_socket_listen_sync(listen_ioc, saddr, errp) < 0) {
+        object_unref(OBJECT(listen_ioc));
+        qapi_free_SocketAddress(saddr);
         return;
     }
 
-    qemu_set_fd_handler(s, unix_accept_incoming_migration, NULL,
+    qio_channel_add_watch(QIO_CHANNEL(listen_ioc),
-                        (void *)(intptr_t)s);
+                          G_IO_IN,
+                          unix_accept_incoming_migration,
+                          listen_ioc,
+                          (GDestroyNotify)object_unref);
+
+    qapi_free_SocketAddress(saddr);
 }

trace-events

@@ -1595,6 +1595,11 @@ postcopy_ram_incoming_cleanup_entry(void) ""
 postcopy_ram_incoming_cleanup_exit(void) ""
 postcopy_ram_incoming_cleanup_join(void) ""
 
+# migration/unix.c
+migration_unix_incoming_accepted(void) ""
+migration_unix_outgoing_connected(void) ""
+migration_unix_outgoing_error(const char *err) "error=%s"
+
 # kvm-all.c
 kvm_ioctl(int type, void *arg) "type 0x%x, arg %p"
 kvm_vm_ioctl(int type, void *arg) "type 0x%x, arg %p"