Bug 532138

Description of problem:
We recently introduced the -M option in fence_ipmilan to support different methods to reboot when fencing (either "onoff" or "cycle") in this BZ:

https://bugzilla.redhat.com/show_bug.cgi?id=522529

The introduction of this attempts to allow you to set -M if needed.  If it is unset after reading in all arguments, we try to default to "onoff" here:

        if (!strlen(method))
                snprintf(method, sizeof(method), "onoff");

A few lines down from here, we test to make sure method is set to either "onoff" or "cycle" and bomb out if it isn't:

        if (strcasecmp(method, "onoff") &&
            strcasecmp(method, "cycle")) {
                fail_exit("method, if included, muse be 'onoff', 'cycle'.");

Somehow, I kept hitting this block of code and the fence agent kept failing with:

failed: method, if included, muse be 'onoff', 'cycle'.

even though I wasn't using -M at all.  Dropping in a few debug statements and looking through this a bit, I believe this is because we never properly initialize the method variable, so sometimes the random chunk of memory it grabs when allocating "char method[64];" is detected as a non-zero length string.

Unfortunately, this isn't always reproducible...sometimes it works fine, other times it fails like above.

I also believe this introduces a possible regression, because previously existing clusters using the fence_ipmilan fence agent without a method specified (since it didn't exist until just recently) are vulnerable to breakage because of this.



Version-Release number of selected component (if applicable):
# rpm -q cman
cman-2.0.115-1.el5_4.3

# fence_ipmilan -V
fence_ipmilan 2.0.115 (built Sep 29 2009 08:55:13)
Copyright (C) Red Hat, Inc.  2004  All rights reserved.



How reproducible:
Rather randomly.



Steps to Reproduce:
1. upgrade to the newest cman package above which includes the new "method" option for fence_ipmilan
2. issue fence_ipmilan without using a -M option 


  
Actual results:
Sometimes, fencing fails with "failed: method, if included, muse be 'onoff', 'cycle'."



Expected results:
Fencing event should complete successfully.  If no -M is specified, then the option should properly default to "onoff".



Additional info:
This is a pretty simple one line patch to properly initialize the method variable:

diff -up ./fence/agents/ipmilan/ipmilan.c.ORIG ./fence/agents/ipmilan/ipmilan.c
--- ./fence/agents/ipmilan/ipmilan.c.ORIG       2009-10-30 16:36:43.000000000 -0400
+++ ./fence/agents/ipmilan/ipmilan.c 2009-10-30 16:37:33.000000000 -0400
@@ -1064,6 +1064,7 @@ main(int argc, char **argv)
  memset(passwd, 0, sizeof(passwd));
  memset(user, 0, sizeof(user));
  memset(op, 0, sizeof(op));
+ memset(method, 0, sizeof(method));

  if (argc > 1) {
    /*