[Qemu-devel] [RFC PATCH 1/2] migration: Allow the migrate command to work on file:urls

[zhanghailiang <zhang.zhanghailiang@huawei.com>]

Usage:
(qemu) migrate file:/path/to/vm_statefile

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Benoit Canet <benoit.canet@gmail.com>
---
 include/migration/migration.h |  2 ++
 migration/fd.c                | 34 ++++++++++++++++++++++++++++------
 migration/migration.c         |  2 ++
 migration/trace-events        |  1 +
 4 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/include/migration/migration.h b/include/migration/migration.h
index 3c96623..cc2e4f6 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -221,6 +221,8 @@ void fd_start_incoming_migration(const char *path, Error **errp);
 
 void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp);
 
+void file_start_outgoing_migration(MigrationState *s, const char *filename, Error **errp);
+
 void rdma_start_outgoing_migration(void *opaque, const char *host_port, Error **errp);
 
 void rdma_start_incoming_migration(const char *host_port, Error **errp);
diff --git a/migration/fd.c b/migration/fd.c
index 84a10fd..fa5df67 100644
--- a/migration/fd.c
+++ b/migration/fd.c
@@ -23,15 +23,11 @@
 #include "trace.h"
 
 
-void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
+static void fd_start_outgoing_migration_core(MigrationState *s, int fd,
+                                             Error **errp)
 {
     QIOChannel *ioc;
-    int fd = monitor_get_fd(cur_mon, fdname, errp);
-    if (fd == -1) {
-        return;
-    }
 
-    trace_migration_fd_outgoing(fd);
     ioc = qio_channel_new_fd(fd, errp);
     if (!ioc) {
         close(fd);
@@ -42,6 +38,32 @@ void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **
     object_unref(OBJECT(ioc));
 }
 
+void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
+{
+    int fd = monitor_get_fd(cur_mon, fdname, errp);
+    if (fd == -1) {
+        return;
+    }
+
+    trace_migration_fd_outgoing(fd);
+    fd_start_outgoing_migration_core(s, fd, errp);
+}
+
+void file_start_outgoing_migration(MigrationState *s, const char *filename,
+                                   Error **errp)
+{
+    int fd;
+
+    fd = qemu_open(filename, O_CREAT | O_TRUNC | O_WRONLY, S_IRUSR | S_IWUSR);
+    if (fd < 0) {
+        error_setg_errno(errp, errno, "Failed to open file: %s", filename);
+        return;
+    }
+    
+    trace_migration_file_outgoing(filename);
+    fd_start_outgoing_migration_core(s, fd, errp);
+}
+
 static gboolean fd_accept_incoming_migration(QIOChannel *ioc,
                                              GIOCondition condition,
                                              gpointer opaque)
diff --git a/migration/migration.c b/migration/migration.c
index c4e0193..097adba 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1109,6 +1109,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
         unix_start_outgoing_migration(s, p, &local_err);
     } else if (strstart(uri, "fd:", &p)) {
         fd_start_outgoing_migration(s, p, &local_err);
+    } else if (strstart(uri, "file:", &p)) {
+        file_start_outgoing_migration(s, p, &local_err);
     } else {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
                    "a valid migration protocol");
diff --git a/migration/trace-events b/migration/trace-events
index 8568dab..4fca64c 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -194,6 +194,7 @@ migration_exec_incoming(const char *cmd) "cmd=%s"
 # migration/fd.c
 migration_fd_outgoing(int fd) "fd=%d"
 migration_fd_incoming(int fd) "fd=%d"
+migration_file_outgoing(const char *filename) "file=%s"
 
 # migration/socket.c
 migration_socket_incoming_accepted(void) ""
-- 
1.8.3.1