To set both titles from vim, use its termcap-title options to push the title to screen using the iconstring. When not running under screen, the right titlestring escapes will be inferred from terminfo.

set title
auto BufEnter * let &titlestring = s:MyTitle()

if &term =~ 'screen\(\.\(xterm\|rxvt\)\(-\(256\)\?color\)\?\)\?'
  " Set the screen title using the vim "iconstring"."
  set t_IS=^[k
  set t_IE=^[\
  set icon
  auto BufEnter * let &iconstring = &titlestring
  " Set the xterm title using the vim "titlestring"."
  set t_ts=^[]2;
  set t_fs=^G
endif

where the underlined characters are actual escapes input with ^V, not with literal carets.

As for generating a fancy title string like vim: there are some gotchas. The biggest is that vim does not preserve logical directory names, so getcwd() will resolve symlinks, leading to a different location string than generated by zsh’s %~. Rather than call pwd -L, we might as well unify the expansion syntax and call zsh. Of course, it’s nice to have a fallback, too:

" Perform zsh-like prompt expansion using the template {prompt}.  See
" "EXPANSION OF PROMPT SEQUENCES" in zshmisc(1).
function s:ZshPromptExpn(prompt)
  if &shell == "/bin/zsh"
    return system("print -Pn " . shellescape(a:prompt))
  else
    " Fallback to poor man's prompt expansion.
    " By no means equivalent to zsh.
    let idx = 0
    let result = ''
    let escapere = '%\([%)m]\|\(\(-\?[0-9]\+\)\?[~]\)\)'
    while idx < len(a:prompt)
      let nextesc = match(a:prompt, escapere, idx)
      if nextesc < 0
        let result .= a:prompt[idx :]
        break
      elseif idx < nextesc
        let result .= a:prompt[idx : (nextesc - 1)]
      endif

      let idx = matchend(a:prompt, escapere, nextesc)
      let esc = a:prompt[nextesc : (idx - 1)]
      if esc == '%m'
        let result .= substitute(hostname(), '^\([^.]*\).*', '\1', '')
      elseif esc =~ '%-\?[0-9]*[~]'
        let result .= fnamemodify(getcwd(), ':~')[:-2]
      elseif esc == '%%'
        let result .= '%'
      endif
    endwhile
    return result
endfunction

function s:MyTitle()
  return s:ZshPromptExpn("%m:%-3~ ") .
  \ v:progname . " " . fnamemodify(expand("%:f"), ":.")
endfunction

The Option has a somewhat unorthodox binary format with non-power-of-2-width fixed point reals. To make generating the DHCP configuration statements easier, I developed a web-based RFC 3825 location configuration generation tool. It’s all client-side and even has a Google Maps preview of the location!

Copy the configuration to your local DHCP server, grab an appropriate geolocation library, and you’re ready to go! The tool generates a DHCP LCI Option for both dnsmasq and ISC’s dhcpd.

The lack of fixed point integers in Javascript made the implementation a little trickier than it would have been in, say, C.

Other lessons: Google Maps is not highly accurate.

I went through the HTML suggestions from the google webmaster tools and Google’s own SEO Starter Guide. I’ve pushed the search engine optimized cgit to my seo branch on github. You can see it in action at my git repositories. I’m testing all of this using an Apache ScriptAlias directive, I’m hoping it will still work alright with whatever other URL-processing schemes cgit supports. A short summary of the new SEO features so far:

• Use HTML h1 and h2 heading tags instead of custom-styled divs
• Much better title tags; commits have the commit subject, and the repo name has been added in a lot of places to avoid duplicate titles
• The bread-crumb has been integrated into the heading
• A configurable option to set nofollow relationships on links to non-HEAD commits, to avoid duplicate content being indexed

Of course, you could take the popular option of just using github instead of self-hosting your own git web interfaces… but even they don’t do quite a good a job IMO, they use the SHA1 in the web page titles, eww!

In RFC 1123 it is stipulated that:

a DNS resolver or server that is sending a non-zone-transfer query MUST send a UDP query first.

However, if you are doing a DNS UPDATE you really want the reliability that TCP offers, even if you don’t expect truncation to be an issue. The update is sent to the relevant authority server, so the arguments about load on root servers in the RFC aren’t applicable.

I’ve made the UDP implementation retry by default, but I think if you need more than 2 retries, you should be considering using TCP with its (much more advanced) retransmission algorithms.

Peter also found a bug in glibc’s res_send (actually in their send_dg function) whereby the resolver interprets the lack of the DNS “recursion available” flag in the header as an error. However, that flag isn’t even meaningful for DNS UPDATE responses; according to RFC 2136, those bits:

Should be zero (0) in all requests and responses. A non-zero Z field should be ignored by implementations of this specification.

As a result, glibc was setting errno to ECONNREFUSED or ETIMEDOUT even when the update was successful. I’ve hacked dudders to double-check after res_send, but it’s making me question the wisdom of using res_send at all, given that I’m constantly working around it.

Update: submitted glibc bug report #11950

To get dudders-1.04 on OpenWRT, simply update the official package feed and select dudders from the Net > DNS > dudders menu in the buildroot config. For systems other than OpenWRT, you can grab the source from sourceforge, or even github.