ceph-disk: more robust parted output parser

In some cases, depending on the implementation or the operating system,

   parted --machine -- /dev/sdh print

may contain empty lines. The current parsing code is fragile and highly
depends on output details. Replace it with code that basically does the
same sanity checks (output not empty, existence of units, existence of
the dev entry) but handles the entire output instead of checking line by
line.

http://tracker.ceph.com/issues/10983 Fixes: #10983

Signed-off-by: Loic Dachary <ldachary@redhat.com>
(cherry picked from commit f5acf6bb6a342b05897605703d7d9cb7c09714fd)

diff --git a/src/ceph-disk b/src/ceph-disk
index c3c6951442093c0b530907c85ee7a1978bfd1d1c..70c713777904c9cc6d97be05aaad85deb83a582e 100755 (executable)
--- a/src/ceph-disk
+++ b/src/ceph-disk
@@ -964,6 +964,9 @@ def unmount(
 
 ###########################################
 
+def extract_parted_partition_numbers(partitions):
+    numbers_as_strings = re.findall('^\d+', partitions, re.MULTILINE)
+    return map(int, numbers_as_strings)
 
 def get_free_partition_index(dev):
     """
@@ -988,31 +991,19 @@ def get_free_partition_index(dev):
 
     if not lines:
         raise Error('parted failed to output anything')
-    lines = str(lines).splitlines(True)
-
-    # work around buggy libreadline(?) library in rhel/centos.
-    idiot_prefix = '\x1b\x5b\x3f\x31\x30\x33\x34\x68'
-    if lines[0].startswith(idiot_prefix):
-        lines[0] = lines[0][8:]
-
-    if lines[0] not in ['CHS;\n', 'CYL;\n', 'BYT;\n']:
-        raise Error('weird parted units', lines[0])
-    del lines[0]
-
-    if not lines[0].startswith('/dev/'):
-        raise Error('weird parted disk entry', lines[0])
-    del lines[0]
-
-    seen = set()
-    for line in lines:
-        idx, _ = line.split(':', 1)
-        idx = int(idx)
-        seen.add(idx)
-
-    num = 1
-    while num in seen:
-        num += 1
-    return num
+    if ('CHS;' not in lines and
+        'CYL;' not in lines and
+        'BYT;' not in lines):
+        raise Error('parted output expected to contain one of ' +
+                    'CHH; CYL; or BYT; : ' + lines)
+    if dev not in lines:
+        raise Error('parted output expected to contain ' + dev + ': ' + lines)
+    _, partitions = lines.split(dev)
+    partition_numbers = extract_parted_partition_numbers(partitions)
+    if partition_numbers:
+        return max(partition_numbers) + 1
+    else:
+        return 1
 
 
 def update_partition(action, dev, description):