[master 8/30] Add a distinct task for reading filesytem labels.

mulkieran installerbot-noreply at redhat.com
Wed Mar 25 22:47:46 UTC 2015


From: mulhern <amulhern at redhat.com>

Signed-off-by: mulhern <amulhern at redhat.com>
---
 blivet/tasks/fsreadlabel.py | 158 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 158 insertions(+)
 create mode 100644 blivet/tasks/fsreadlabel.py

diff --git a/blivet/tasks/fsreadlabel.py b/blivet/tasks/fsreadlabel.py
new file mode 100644
index 0000000..9a485a1
--- /dev/null
+++ b/blivet/tasks/fsreadlabel.py
@@ -0,0 +1,158 @@
+# fsreadlabel.py
+# Filesystem label reading classes.
+#
+# Copyright (C) 2015  Red Hat, Inc.
+#
+# This copyrighted material is made available to anyone wishing to use,
+# modify, copy, or redistribute it subject to the terms and conditions of
+# the GNU General Public License v.2, or (at your option) any later version.
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY expressed or implied, including the implied warranties of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+# Public License for more details.  You should have received a copy of the
+# GNU General Public License along with this program; if not, write to the
+# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the
+# source code or documentation are not subject to the GNU General Public
+# License and may only be used or replicated with the express permission of
+# Red Hat, Inc.
+#
+# Red Hat Author(s): Anne Mulhern <amulhern at redhat.com>
+
+import abc
+import os
+import re
+
+from six import add_metaclass
+
+from ..errors import FSReadLabelError
+from .. import util
+
+from . import availability
+from . import task
+
+ at add_metaclass(abc.ABCMeta)
+class FSReadLabel(task.Task):
+    """ An abstract class that represents reading a filesystem's label. """
+    description = "read filesystem label"
+
+    app_name = abc.abstractproperty(
+       doc="The name of the filesystem labeling application.")
+
+    label_regex = abc.abstractproperty(
+        doc="Matches the string output by the reading application.")
+
+    args = abc.abstractproperty(doc="arguments for reading a label.")
+
+    @classmethod
+    def _app(cls):
+        return availability.Application(availability.Path(), cls.app_name)
+
+    def __init__(self, an_fs):
+        """ Initializer.
+
+           :param FS an_fs: a filesystem object
+        """
+        self.fs = an_fs
+
+    # TASK methods
+
+    @classmethod
+    def available(cls):
+        return cls._app().available
+
+    @property
+    def unavailable(self):
+        if not self._app().available:
+            return "application %s is not available" % self._app()
+
+        return False
+
+    @property
+    def unready(self):
+        if not self.fs.exists:
+            return "filesystem has not been created"
+
+        if not os.path.exists(self.fs.device):
+            return "device %s does not exist" % self.fs.device.name
+
+        return False
+
+    @property
+    def unable(self):
+        return False
+
+    # IMPLEMENTATION methods
+
+    def _readCommand(self):
+        """Get the command to read the filesystem label.
+
+           :return: the command
+           :rtype: list of str
+        """
+        return [str(self._app())] + self.args
+
+    def _extractLabel(self, labelstr):
+        """Extract the label from an output string.
+
+           :param str labelstr: the string containing the label information
+
+           :return: the label
+           :rtype: str
+
+           Raises an FSReadLabelError if the label can not be extracted.
+        """
+        match = re.match(self.label_regex, labelstr)
+        if match is None:
+            raise FSReadLabelError("Unknown format for application %s" % self._app())
+        return match.group('label')
+
+    def doTask(self):
+        """ Get the label.
+
+            :returns: the filesystem label
+            :rtype: str
+        """
+        error_msg = self.impossible
+        if error_msg:
+            raise FSReadLabelError(error_msg)
+
+        (rc, out) = util.run_program_and_capture_output(self._readCommand())
+        if rc:
+            raise FSReadLabelError("read label failed")
+
+        label = out.strip()
+
+        return label if label == "" else self._extractLabel(label)
+
+class DosFSReadLabel(FSReadLabel):
+    app_name = "dosfslabel"
+    label_regex = r'(?P<label>.*)'
+
+    @property
+    def args(self):
+        return [self.fs.device]
+
+class Ext2FSReadLabel(FSReadLabel):
+    app_name = "e2label"
+    label_regex = r'(?P<label>.*)'
+
+    @property
+    def args(self):
+        return [self.fs.device]
+
+class NTFSReadLabel(FSReadLabel):
+    app_name = "ntfslabel"
+    label_regex = r'(?P<label>.*)'
+
+    @property
+    def args(self):
+        return [self.fs.device]
+
+class XFSReadLabel(FSReadLabel):
+    app_name = "xfs_admin"
+    label_regex = r'label = "(?P<label>.*)"'
+
+    @property
+    def args(self):
+        return ["-l", self.fs.device]


-- 
To view this commit on github, visit https://github.com/rhinstaller/blivet/commit/34a817408c08dd238f39434d9ca3c81593a08241


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