add file descriptor migration

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Chris Lalancette <clalance@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 137 insertions, 0 deletions

diff --git a/migration-fd.c b/migration-fd.c
new file mode 100644
index 0000000000..15b44158ff
--- /dev/null
+++ b/migration-fd.c
@@ -0,0 +1,137 @@
+/*
+ * QEMU live migration via generic fd
+ *
+ * Copyright Red Hat, Inc. 2009
+ *
+ * Authors:
+ *  Chris Lalancette <clalance@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "qemu_socket.h"
+#include "migration.h"
+#include "monitor.h"
+#include "qemu-char.h"
+#include "sysemu.h"
+#include "buffered_file.h"
+#include "block.h"
+#include "qemu_socket.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 int fd_errno(FdMigrationState *s)
+{
+    return errno;
+}
+
+static int fd_write(FdMigrationState *s, const void * buf, size_t size)
+{
+    return write(s->fd, buf, size);
+}
+
+static int fd_close(FdMigrationState *s)
+{
+    dprintf("fd_close\n");
+    if (s->fd != -1) {
+        close(s->fd);
+        s->fd = -1;
+    }
+    return 0;
+}
+
+MigrationState *fd_start_outgoing_migration(Monitor *mon,
+					    const char *fdname,
+					    int64_t bandwidth_limit,
+					    int detach)
+{
+    FdMigrationState *s;
+
+    s = qemu_mallocz(sizeof(*s));
+
+    s->fd = monitor_get_fd(mon, fdname);
+    if (s->fd == -1) {
+        dprintf("fd_migration: invalid file descriptor identifier\n");
+        goto err_after_alloc;
+    }
+
+    if (fcntl(s->fd, F_SETFL, O_NONBLOCK) == -1) {
+        dprintf("Unable to set nonblocking mode on file descriptor\n");
+        goto err_after_open;
+    }
+
+    s->get_error = fd_errno;
+    s->write = fd_write;
+    s->close = fd_close;
+    s->mig_state.cancel = migrate_fd_cancel;
+    s->mig_state.get_status = migrate_fd_get_status;
+    s->mig_state.release = migrate_fd_release;
+
+    s->state = MIG_STATE_ACTIVE;
+    s->mon_resume = NULL;
+    s->bandwidth_limit = bandwidth_limit;
+
+    if (!detach)
+        migrate_fd_monitor_suspend(s);
+
+    migrate_fd_connect(s);
+    return &s->mig_state;
+
+err_after_open:
+    close(s->fd);
+err_after_alloc:
+    qemu_free(s);
+    return NULL;
+}
+
+static void fd_accept_incoming_migration(void *opaque)
+{
+    QEMUFile *f = opaque;
+    int ret;
+
+    ret = qemu_loadvm_state(f);
+    if (ret < 0) {
+        fprintf(stderr, "load of migration failed\n");
+        goto err;
+    }
+    qemu_announce_self();
+    dprintf("successfully loaded vm state\n");
+    /* we've successfully migrated, close the fd */
+    qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
+    if (autostart)
+        vm_start();
+
+err:
+    qemu_fclose(f);
+}
+
+int fd_start_incoming_migration(const char *infd)
+{
+    int fd;
+    QEMUFile *f;
+
+    dprintf("Attempting to start an incoming migration via fd\n");
+
+    fd = strtol(infd, NULL, 0);
+    f = qemu_fdopen(fd, "rb");
+    if(f == NULL) {
+        dprintf("Unable to apply qemu wrapper to file descriptor\n");
+        return -errno;
+    }
+
+    qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL,
+			 (void *)(unsigned long)f);
+
+    return 0;
+}