Add a parser for 'multipath -d' output.

We need to find out about multipath topology from /sbin/multipath, which
unfortunately needs some parsing - it's fairly easy, though.

1 files changed, 47 insertions, 0 deletions

diff --git a/storage/devicelibs/mpath.py b/storage/devicelibs/mpath.py
index 67c60f0c8..322df8e40 100644
--- a/storage/devicelibs/mpath.py
+++ b/storage/devicelibs/mpath.py
@@ -1,5 +1,52 @@
 from ..udev import *
 
+def parseMultipathOutput(output):
+    # this function parses output from "multipath -d", so we can use its
+    # logic for our topology.
+    # The input looks like:
+    # create: mpathb (1ATA     ST3120026AS                                         5M) undef ATA,ST3120026AS
+    # size=112G features='0' hwhandler='0' wp=undef
+    # `-+- policy='round-robin 0' prio=1 status=undef
+    #   `- 2:0:0:0 sda 8:0  undef ready running
+    # create: mpatha (36006016092d21800703762872c60db11) undef DGC,RAID 5
+    # size=10G features='1 queue_if_no_path' hwhandler='1 emc' wp=undef
+    # `-+- policy='round-robin 0' prio=2 status=undef
+    #   |- 6:0:0:0 sdb 8:16 undef ready running
+    #   `- 7:0:0:0 sdc 8:32 undef ready running
+    #
+    # (In anaconda, the first one there won't be included because we blacklist
+    # "ATA" as a vendor.)
+    #
+    # It returns a structure like:
+    # [ {'mpatha':['sdb','sdc']}, ... ]
+    mpaths = {}
+
+    name = None
+    devices = []
+
+    lines = output.split('\n')
+    for line in lines:
+        lexemes = line.split()
+        if not lexemes:
+            break
+        if lexemes[0] == 'create:':
+            if name and devices:
+                mpaths.append(mpath)
+                name = None
+                devices = []
+            name = lexemes[1]
+        elif lexemes[0].startswith('size='):
+            pass
+        elif lexemes[0] == '`-+-':
+            pass
+        elif lexemes[0] in ['|-','`-']:
+            devices.append(lexemes[2])
+    
+    if name and devices:
+        mpaths[name] = devices
+
+    return mpaths
+
 def identifyMultipaths(devices):
     # this function does a couple of things
     # 1) identifies multipath disks