CloudSigma: only poll on serial device after dmidecode check.

On systems with a ttyS1 and nothing attached, the read attempts
that the cloud sigma datasource would do would block.

Also, Add timeouts for reading/writting from/to the serial console

LP: #1316475

1 files changed, 30 insertions, 0 deletions

diff --git a/cloudinit/sources/DataSourceCloudSigma.py b/cloudinit/sources/DataSourceCloudSigma.py
index ad2a044a..707cd0ce 100644
--- a/cloudinit/sources/DataSourceCloudSigma.py
+++ b/cloudinit/sources/DataSourceCloudSigma.py
@@ -16,10 +16,12 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 from base64 import b64decode
+import os
 import re
 
 from cloudinit import log as logging
 from cloudinit import sources
+from cloudinit import util
 from cloudinit.cs_utils import Cepko
 
 LOG = logging.getLogger(__name__)
@@ -40,12 +42,40 @@ class DataSourceCloudSigma(sources.DataSource):
         self.ssh_public_key = ''
         sources.DataSource.__init__(self, sys_cfg, distro, paths)
 
+    def is_running_in_cloudsigma(self):
+        """
+        Uses dmidecode to detect if this instance of cloud-init is running
+        in the CloudSigma's infrastructure.
+        """
+        uname_arch = os.uname()[4]
+        if uname_arch.startswith("arm") or uname_arch == "aarch64":
+            # Disabling because dmidecode in CMD_DMI_SYSTEM crashes kvm process
+            LOG.debug("Disabling CloudSigma datasource on arm (LP: #1243287)")
+            return False
+
+        dmidecode_path = util.which('dmidecode')
+        if not dmidecode_path:
+            return False
+
+        LOG.debug("Determining hypervisor product name via dmidecode")
+        try:
+            cmd = [dmidecode_path, "--string", "system-product-name"]
+            system_product_name, _ = util.subp(cmd)
+            return 'cloudsigma' in system_product_name.lower()
+        except:
+            LOG.warn("Failed to get hypervisor product name via dmidecode")
+
+        return False
+
     def get_data(self):
         """
         Metadata is the whole server context and /meta/cloud-config is used
         as userdata.
         """
         dsmode = None
+        if not self.is_running_in_cloudsigma():
+            return False
+
         try:
             server_context = self.cepko.all().result
             server_meta = server_context['meta']