Description of problem:

The check_host_list()  [source: xlators/mgmt/glusterd/src/glusterd-ganesha.c] function is currently quite weak and segfault prone.

That function parses the /etc/ganesha/ganesha-ha.conf file

----8<----
       while (fgets (line, sizeof(line), fp) != NULL) {
        /* Read GANESHA_HA_CONFIG till we find the list of HA_CLUSTER_NODES */
                hostname = strstr ((char *)line, "HA_CLUSTER_NODES");
                if (hostname != NULL) {
                        hostname = strstr (hostname, DELIM);
                        hostname = hostname + strlen(DELIM);
                        i = strlen (hostname);
                        hostname[i - 2] = '\0';
                        break;
                }
---->8----

1) The second strstr might return NULL if DELIM (i.e. : defined as '="') does not appear in the line.
e.g. : an admin might believe that quotes are not mandatory, or that single quote is good as well.

2) There is currently no comment checking ('#'), which means that the following config file will get the wrong value :
---
#HA_CLUSTER_NODES="oldname1,oldname2,oldname3"
HA_CLUSTER_NODES="newname1,newname2,newname3"
---

because the first line will match, despite being commented out.

3) There is no comment checking after the value either, nor do we check that the last character is a quote before removing it. Thus this will fail :
HA_CLUSTER_NODES="server1,server2"  # some comment

4) there's a potential problem with long lines : line[] is statically set to 1024 chars, and is prone to future problem (see http://review.gluster.org/#/c/12346/ for similar issues)

Version-Release number of selected component (if applicable): 3.1, and upstream is affected as well

How reproducible: 100%


Steps to Reproduce:
1. have a buggy /etc/ganesha/ganesha-ha.conf
2. enable nfs-ganesha

Actual results:
segfaults, without any error message

Expected results:
1) stronger check_host_list() function that accepts comments
2) parsing check, so that we have an elegant error, like "error: could not parse HA_CLUSTER_NODES"