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>

diff --git a/src/ceph-disk b/src/ceph-disk
index 73990cc6e5ffccdd7a85b0e690962dd347d28401..e932a83b0ab3de61a730728f6bad22b80d191e10 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):