[Libguestfs] [PATCH 1/4] p2v: Wait for network to come online before testing connection (RHBZ#1256222).

[Richard W.M. Jones]

When using the virt-p2v ISO in command line mode, we did not wait for
the network to come online before starting virt-p2v.  Therefore
virt-p2v could exit with an error when testing the ssh connection (or
on the other hand, it might work randomly).  If the user logs in and
runs 'launch-virt-p2v' by hand, then it would usually work because the
network had been brought online in the meantime.

Fix this by waiting for NetworkManager to bring the connection online
before calling test_connection().  Note that the obvious way to fix
this (changing the systemd service to wait for network-online.target)
does *not* work - I added a comment to the service about this.

Thanks: Tingting Zheng
---
 p2v/gui.c       |  3 +++
 p2v/kernel.c    |  1 +
 p2v/p2v.h       |  1 +
 p2v/p2v.service |  5 +++++
 p2v/utils.c     | 22 ++++++++++++++++++++++
 5 files changed, 32 insertions(+)

diff --git a/p2v/gui.c b/p2v/gui.c
index 10d29e2..b3ad05d 100644
--- a/p2v/gui.c
+++ b/p2v/gui.c
@@ -324,8 +324,11 @@ test_connection_thread (void *data)
                       _("Testing the connection to the conversion server ..."));
   gtk_spinner_start (GTK_SPINNER (spinner));
   gdk_threads_leave ();
+
+  wait_network_online (copy);
   r = test_connection (copy);
   free_config (copy);
+
   gdk_threads_enter ();
   gtk_spinner_stop (GTK_SPINNER (spinner));
 
diff --git a/p2v/kernel.c b/p2v/kernel.c
index b283417..9fec47f 100644
--- a/p2v/kernel.c
+++ b/p2v/kernel.c
@@ -81,6 +81,7 @@ kernel_configuration (struct config *config, char **cmdline, int cmdline_source)
    */
   p = get_cmdline_key (cmdline, "p2v.skip_test_connection");
   if (!p) {
+    wait_network_online (config);
     if (test_connection (config) == -1) {
       const char *err = get_ssh_error ();
 
diff --git a/p2v/p2v.h b/p2v/p2v.h
index c9cd653..34f6bcf 100644
--- a/p2v/p2v.h
+++ b/p2v/p2v.h
@@ -119,6 +119,7 @@ extern const char *get_ssh_error (void);
 /* utils.c */
 extern char *get_if_addr (const char *if_name);
 extern char *get_if_vendor (const char *if_name, int truncate);
+extern void wait_network_online (const struct config *);
 
 /* virt-v2v version and features (read from remote). */
 extern int v2v_major;
diff --git a/p2v/p2v.service b/p2v/p2v.service
index a6b5e25..a6c4cd9 100644
--- a/p2v/p2v.service
+++ b/p2v/p2v.service
@@ -20,6 +20,11 @@
 
 [Unit]
 Description=p2v service
+# For the GUI, we cannot necessarily wait for the network to come
+# online, since that may require the "Configure Network" dialog.  For
+# the command line, we would like the network to be online, but we
+# test that within virt-p2v itself.  Therefore use network.target
+# here, not network-online.target.
 After=network.target
 
 [Service]
diff --git a/p2v/utils.c b/p2v/utils.c
index 0b30be3..3781a8d 100644
--- a/p2v/utils.c
+++ b/p2v/utils.c
@@ -26,6 +26,8 @@
 #include <locale.h>
 #include <libintl.h>
 
+#include "ignore-value.h"
+
 #include "p2v.h"
 
 #define CHOMP(line,len)                         \
@@ -134,3 +136,23 @@ get_if_vendor (const char *if_name, int truncate)
   free (line);
   return NULL;
 }
+
+/* Wait for the network to come online, but don't error out if that
+ * fails.  The caller will call test_connection immediately after this
+ * which will fail if the network didn't come online.
+ */
+
+/* XXX We could make this configurable. */
+#define NETWORK_ONLINE_COMMAND "nm-online -t 30"
+
+void
+wait_network_online (const struct config *config)
+{
+  if (config->verbose) {
+    printf ("waiting for the network to come online ...\n");
+    printf ("%s\n", NETWORK_ONLINE_COMMAND);
+    fflush (stdout);
+  }
+
+  ignore_value (system (NETWORK_ONLINE_COMMAND));
+}
-- 
2.5.0