[Toybox] [PATCH] Fix ls -sh.

[Rob Landley]

On 08/27/2016 12:25 PM, enh wrote:
> ping. (i'd like to get this into my weekly sync, since it was reported
> as a bug.)

Sorry, I wanted to take a stab at cleaning up the redundancy, but my
todo list hit some sort of critical mass a couple months back and has
not let up. (Downside of a day job that does _not_ let you devote half
of each working day to open source stuff. I spent bits of today reading
about tun/tap, in hopes of clearing that and getting back to the xattr
stuff.)

Cleanup, cleanup... hmmm, is human_readable ever going to produce utf8
output that cares about strwidth() vs strlen()? No, doesn't look like,
which means I've got an overzealous strwidth() in there tha can go...

Hmmm, it still doesn't match the host's output exactly for ls -sh
because they're using two spaces of padding between columns and we're
only using one. (This isn't a -h thing though, ls -s does it too, and we
hadn't noticed/cared before...)

> i did write a test, but removed it again because assumptions about
> blocks used by the test files seemed inherently flaky.

It's the "stat %B vs %o" thing all over again. According to "man 2 stat"
the units of st_blocks are always 512 bytes, hardwired for historical
reasons. I'll update the help text.

Except...

  $ ls -l stat
  -r-xr-xr-x 1 landley landley 23000 Aug 27 21:54 stat
  $ ls -s stat
  24 stat
  $ toybox ls -s stat
  48 stat

The host _isn't_ doing that, it's using 1024 byte units. (Sort of,
dividing the stat value by 2.)

Sigh, what does the man page say?

       -s, --size
              print the allocated size of each file, in blocks

Nothing. No units! Is this a magic posix thing?

  -s
      Indicate the total number of file system blocks consumed by each
      file displayed. If the -k option is also specified, the block
      size shall be 1024 bytes; otherwise, the block size is
      implementation-defined.

Not exactly. It looks like the host is hardwiring -k on. Sigh. I can do
that too. (Opinions? I didn't think it _used_ to do that, but I keep
upgrading my ubuntu version and the behavior of ls subtly changes out
from under me and what I tested against is no longer true...)

Anyway, the usefulness of the -s field is when there's holes, but it
might as well be "actual bytes used". I'd happily change it to use units
of bytes, but compatibility... (Although see above!)

As long as we're twiddling -h, do you want it to change the date format
to do the "Aug 27 12:34" thing (instead of "2016-08-27 12:34"?) It seems
like -h is a logical place to do that since a script can't reasonably
parse the result _anyway_. (I can just let strftime's %b supply the
month name. I'd try %c but "Sat Aug 27 12:34:56 2016" isn't even close. :)

Rob