From 4c634d3f9a93a3bd07aed0be7972884cf0955c07 Mon Sep 17 00:00:00 2001
From: lars <lars@systemausfall.org>
Date: Mon, 14 Jan 2008 20:46:42 +0000
Subject: [PATCH] remember if lvm is not installed

---
 src/cryptobox/core/blockdevice.py | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/src/cryptobox/core/blockdevice.py b/src/cryptobox/core/blockdevice.py
index dccb7b0..13abc4e 100644
--- a/src/cryptobox/core/blockdevice.py
+++ b/src/cryptobox/core/blockdevice.py
@@ -34,6 +34,12 @@ import time
 import logging
 import cryptobox.core.settings
 
+OPTIONAL_PROGS = { "lvm": True }
+"""remember which programs don't exist to avoid calling them in vain
+
+change default values from "True" to "False" to disable the respective program
+"""
+
 LOGGER = logging.getLogger("CryptoBox")
 
 DEFAULT_SYSBLOCK_DIR = '/sys/block'
@@ -510,6 +516,9 @@ class Blockdevice:
     def __get_uuid_lvm_pv(self):
         """determine the unique identifier of physical LVM volumes
         """
+        if not OPTIONAL_PROGS["lvm"]:
+            ## pvdisplay is not installed - skip it
+            return None
         prefs = _load_preferences()
         try:
             proc = subprocess.Popen(
@@ -524,6 +533,11 @@ class Blockdevice:
             LOGGER.warning("Failed to call '%s' via 'super' to determine " \
                     % prefs["Programs"]["pvdisplay"] + "UUID: %s" % err_msg)
             return None
+        if proc.returncode == 101:
+            ## pvdisplay is not installed
+            OPTIONAL_PROGS["lvm"] = False
+            LOGGER.warning("'lvm' is not installed - I will not try it again")
+            return None
         if proc.returncode != 0:
             LOGGER.warning("Execution of 'pvdisplay' failed: %s" % error)
             return None
@@ -837,6 +851,8 @@ def find_blockdevices(top_dir):
 def find_lvm_pv():
     """return the blockdevice names of all physical LVM volumes
     """
+    if not OPTIONAL_PROGS["lvm"]:
+        return []
     cache_link = ["lvm", "pv"]
     cached = CACHE.get(cache_link)
     if not cached is None:
@@ -856,6 +872,11 @@ def find_lvm_pv():
     except OSError, err_msg:
         LOGGER.info("Failed to call 'pvdisplay' via 'super': %s" % err_msg)
         result = []
+    if proc.returncode == 101:
+        ## pvdisplay is not installed
+        OPTIONAL_PROGS["lvm"] = False
+        LOGGER.warning("'lvm' is not installed - I will not try it again")
+        return []
     if proc.returncode != 0:
         LOGGER.info("Execution of 'pvdisplay' failed: %s" % error.strip())
         result = []