whew. finally done block.py.

the msdos table primary/extended/logical thing was a pain but the
logic wasn't too bad.

aif/disk/filesystem.py

@@ -0,0 +1,75 @@
+import os
+import re
+import subprocess
+##
+import psutil
+##
+from aif.disk.block import Partition
+from aif.disk.luks import LUKS
+from aif.disk.lvm import Group as LVMGroup
+from aif.disk.mdadm import Array as MDArray
+
+# I wish there was a better way of doing this.
+# https://unix.stackexchange.com/a/98680
+FS_FSTYPES = []
+with open('/proc/filesystems', 'r') as fh:
+    for line in fh.readlines():
+        l = [i.strip() for i in line.split()]
+        if not l:
+            continue
+        if len(l) == 1:
+            FS_FSTYPES.append(l[0])
+        else:
+            FS_FSTYPES.append(l[1])
+_mod_dir = os.path.join('/lib/modules',
+                        os.uname().release,
+                        'kernel/fs')
+_strip_mod_suffix = re.compile(r'(?P<fsname>)\.ko(\.(x|g)?z))?$', re.IGNORECASE)
+for i in os.listdir(_mod_dir):
+    path = os.path.join(_mod_dir, i)
+    fs_name = None
+    if os.path.isdir(path):
+        fs_name = i
+    elif os.path.isfile(path):
+        mod_name = _strip_mod_suffix.search(i)
+        fs_name = mod_name.group('fsname')
+    if fs_name:
+        # The kernel *probably* has autoloading enabled, but in case it doesn't...
+        # TODO: logging!
+        subprocess.run(['modprobe', fs_name])
+        FS_FSTYPES.append(fs_name)
+
+
+class FS(object):
+    def __init__(self, fs_xml, sourceobj):
+        self.xml = fs_xml
+        if not isinstance(sourceobj, (Partition, LUKS, LVMGroup, MDArray)):
+            raise ValueError(('sourceobj must be of type '
+                              'aif.disk.block.Partition, '
+                              'aif.disk.luks.LUKS, '
+                              'aif.disk.lvm.Group, or'
+                              'aif.disk.mdadm.Array'))
+        self.source = sourceobj
+        self.devpath = sourceobj.devpath
+        self.formatted = False
+        self.fstype = self.xml.attrib.get('type')
+
+    def format(self):
+        if self.formatted:
+            return ()
+        # This is a safeguard. We do *not* want to high-format a disk that is mounted.
+        for p in psutil.disk_partitions(all = True):
+            if self.devpath in p:
+                raise RuntimeError(('{0} is mounted;'
+                                    'we are cowardly refusing to apply a filesystem to it').format(self.devpath))
+        # TODO! Logging
+        cmd = ['mkfs',
+               '-t', self.fstype]
+        for o in self.xml.findall('opt'):
+            cmd.append(o.attrib['name'])
+            if o.text:
+                cmd.append(o.text)
+        cmd.append(self.devpath)
+        subprocess.run(cmd)
+        self.is_hiformatted = True
+        return()