Switch from mach task_info to proc_pidinfo

[fcheung]

The problem with the mach task_info routines is that on modern versions of
macos they require the task_for_pid-allow entitlement in order to get the
mach_task for another process (because there's all sorts of nefarious
things you can do with the mach port)

Since macos 10.5 the proc_* family of functions are a better way for getting
read-only information about processes.

This will still fail if the process is owned by another user. At the moment this raises Errno::EPERM, but should we perhaps rescue that somewhere and fall through to the next case (ps_memory)?

cc #32 #39 #41

[schneems]

Thanks a ton for working on this and for the original PR! I have to ask, how

The failure is from

No checksum for downloaded archive, recording checksum in user configuration.
ruby-2.2.10 - #validate archive
ruby-2.2.10 - #extract
ruby-2.2.10 - #validate binary

Libraries missing for ruby-2.2.10: /usr/local/opt/gdbm/lib/libgdbm.5.dylib,/usr/local/opt/openssl/lib/libcrypto.1.0.0.dylib,/usr/local/opt/openssl/lib/libssl.1.0.0.dylib,/usr/local/opt/readline/lib/libreadline.7.dylib. Refer to your system manual for installing libraries

Mounting remote ruby failed with status 10, stopping installation.
Gemset '' does not exist, 'rvm ruby-2.2.10 do rvm gemset create ' first, or append '--create'.
The command "rvm use 2.2 --install --binary --fuzzy" failed and exited with 2 during .
Your build has been stopped.

I think we can ignore that failure. Having tests run on at least one mac distro seems good enough even if it's only one Ruby version. I started moving over to circleCI but then found that they don't support macOS on the open-source/free tier #43

This will still fail if the process is owned by another user. At the moment this raises Errno::EPERM, but should we perhaps rescue that somewhere and fall through to the next case (ps_memory)?

That would be pretty easy to do here:

  def darwin_memory
    Darwin.resident_size
  rescue Errno::EPERM
    return nil
  end

Then there's an auto fallback to shelling out to ps which would be invoked.

[fcheung]

Thanks a ton for working on this and for the original PR! I have to ask, how

Missing sentence?

That would be pretty easy to do here:

  def darwin_memory
    Darwin.resident_size
  rescue Errno::EPERM
    return nil
  end

Then there's an auto fallback to shelling out to ps which would be invoked.

Cool, i have implemented that

[schneems]

Thanks for all your help (yet again) I've merged this in