[Qemu-devel] [PULL 15/28] migration: convert fd socket protocol to use QIOChannel

[Amit Shah <amit.shah@redhat.com>]

From: "Daniel P. Berrange" <berrange@redhat.com>

Convert the fd socket migration protocol driver to use
QIOChannel and QEMUFileChannel, instead of plain sockets
APIs. It can be unconditionally built because the
QIOChannel APIs it uses will take care to report suitable
error messages if needed.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1461751518-12128-16-git-send-email-berrange@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 migration/Makefile.objs |  4 +--
 migration/fd.c          | 75 +++++++++++++++++++------------------------------
 migration/migration.c   |  4 ---
 trace-events            |  4 +++
 4 files changed, 35 insertions(+), 52 deletions(-)

diff --git a/migration/Makefile.objs b/migration/Makefile.objs
index 4221861..2e5040c 100644
--- a/migration/Makefile.objs
+++ b/migration/Makefile.objs
@@ -1,4 +1,4 @@
-common-obj-y += migration.o socket.o
+common-obj-y += migration.o socket.o fd.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 fd.o
+common-obj-$(CONFIG_POSIX) += exec.o
 
 common-obj-y += block.o
 
diff --git a/migration/fd.c b/migration/fd.c
index 3d788bb..60a75b8 100644
--- a/migration/fd.c
+++ b/migration/fd.c
@@ -1,10 +1,11 @@
 /*
  * QEMU live migration via generic fd
  *
- * 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.
@@ -16,75 +17,57 @@
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qemu-common.h"
-#include "qemu/main-loop.h"
-#include "qemu/sockets.h"
 #include "migration/migration.h"
 #include "monitor/monitor.h"
-#include "migration/qemu-file.h"
-#include "block/block.h"
+#include "io/channel-util.h"
+#include "trace.h"
 
-//#define DEBUG_MIGRATION_FD
-
-#ifdef DEBUG_MIGRATION_FD
-#define DPRINTF(fmt, ...) \
-    do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)
-#else
-#define DPRINTF(fmt, ...) \
-    do { } while (0)
-#endif
-
-static bool fd_is_socket(int fd)
-{
-    struct stat stat;
-    int ret = fstat(fd, &stat);
-    if (ret == -1) {
-        /* When in doubt say no */
-        return false;
-    }
-    return S_ISSOCK(stat.st_mode);
-}
 
 void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
 {
+    QIOChannel *ioc;
     int fd = monitor_get_fd(cur_mon, fdname, errp);
     if (fd == -1) {
         return;
     }
 
-    if (fd_is_socket(fd)) {
-        s->to_dst_file = qemu_fopen_socket(fd, "wb");
-    } else {
-        s->to_dst_file = qemu_fdopen(fd, "wb");
+    trace_migration_fd_outgoing(fd);
+    ioc = qio_channel_new_fd(fd, errp);
+    if (!ioc) {
+        close(fd);
+        return;
     }
 
-    migrate_fd_connect(s);
+    migration_set_outgoing_channel(s, ioc);
+    object_unref(OBJECT(ioc));
 }
 
-static void fd_accept_incoming_migration(void *opaque)
+static gboolean fd_accept_incoming_migration(QIOChannel *ioc,
+                                             GIOCondition condition,
+                                             gpointer opaque)
 {
-    QEMUFile *f = opaque;
-
-    qemu_set_fd_handler(qemu_get_fd(f), NULL, NULL, NULL);
-    process_incoming_migration(f);
+    migration_set_incoming_channel(migrate_get_current(), ioc);
+    object_unref(OBJECT(ioc));
+    return FALSE; /* unregister */
 }
 
 void fd_start_incoming_migration(const char *infd, Error **errp)
 {
+    QIOChannel *ioc;
     int fd;
-    QEMUFile *f;
-
-    DPRINTF("Attempting to start an incoming migration via fd\n");
 
     fd = strtol(infd, NULL, 0);
-    if (fd_is_socket(fd)) {
-        f = qemu_fopen_socket(fd, "rb");
-    } else {
-        f = qemu_fdopen(fd, "rb");
-    }
-    if(f == NULL) {
-        error_setg_errno(errp, errno, "failed to open the source descriptor");
+    trace_migration_fd_incoming(fd);
+
+    ioc = qio_channel_new_fd(fd, errp);
+    if (!ioc) {
+        close(fd);
         return;
     }
 
-    qemu_set_fd_handler(fd, fd_accept_incoming_migration, NULL, f);
+    qio_channel_add_watch(ioc,
+                          G_IO_IN,
+                          fd_accept_incoming_migration,
+                          NULL,
+                          NULL);
 }
diff --git a/migration/migration.c b/migration/migration.c
index a38da3a..8decc7d 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -317,10 +317,8 @@ void qemu_start_incoming_migration(const char *uri, Error **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
     } else {
         error_setg(errp, "unknown migration protocol: %s", uri);
     }
@@ -1077,10 +1075,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
 #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
     } else {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
                    "a valid migration protocol");
diff --git a/trace-events b/trace-events
index 62f634d..e9945e7 100644
--- a/trace-events
+++ b/trace-events
@@ -1595,6 +1595,10 @@ postcopy_ram_incoming_cleanup_entry(void) ""
 postcopy_ram_incoming_cleanup_exit(void) ""
 postcopy_ram_incoming_cleanup_join(void) ""
 
+# migration/fd.c
+migration_fd_outgoing(int fd) "fd=%d"
+migration_fd_incoming(int fd) "fd=%d"
+
 # migration/socket.c
 migration_socket_incoming_accepted(void) ""
 migration_socket_outgoing_connected(void) ""
-- 
2.5.5