BIND 10 #2620: b10-cmdctl-usermgr should check permissions on start

[BIND 10 Development]

#2620: b10-cmdctl-usermgr should check permissions on start
-------------------------------------+-------------------------------------
                   Reporter:  shane  |                 Owner:
                       Type:         |                Status:  new
  defect                             |             Milestone:  New Tasks
                   Priority:         |              Keywords:
  medium                             |             Sensitive:  0
                  Component:         |           Sub-Project:  Core
  Unclassified                       |  Estimated Difficulty:  0
               CVSS Scoring:         |           Total Hours:  0
            Defect Severity:  Low    |
Feature Depending on Ticket:         |
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
-------------------------------------+-------------------------------------
 I tried to add a user:

 {{{
 $ ./b10-cmdctl-usermgr
 Desired Login Name:shane
 Choose a password:
 Re-enter password:
 Traceback (most recent call last):
   File "./b10-cmdctl-usermgr", line 124, in <module>
     main()
   File "./b10-cmdctl-usermgr", line 114, in main
     save_userinfo(name, pw, salt, filename)
   File "./b10-cmdctl-usermgr", line 59, in save_userinfo
     csvfile = open(filename, 'a')
 IOError: [Errno 13] Permission denied: 'cmdctl-accounts.csv'
 }}}

 There should be 2 changes:

 1. The program should check permissions when it starts, so I don't go
 through the steps of adding a user when they won't work.

 2. If for some other reason updating user information fails (permissions
 can change after the program starts, or NFS mounts can disappear, or
 whatever), the program should catch the problem and give a nicer error
 rather than dumping a stack trace.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2620>
BIND 10 Development <http://bind10.isc.org>
BIND 10 Development