We want to have deterministic UUIDs for every device specification in
order to avoid the need to manually set labels all over the place.

Of course, we could internally set labels instead of precomputing UUIDs,
but labels have different length restrictions for every file system (for
example XFS has a maximum of 12 bytes, for ext4 it's 16 bytes). In
addition to that we remove the ability for people to set their own
labels during runtime.

The UUIDs generated here are based on version 5:

https://tools.ietf.org/html/rfc4122#section-4.1.3

Our variant deviates from this a bit in that we use string concatenation
to build up the input for the SHA1 hash instead of binaries. The results
however are pretty much the same and in our part the most important
aspect is determinism rather than having a truly unique value across the
whole planet.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

Having just a single type for a device specification doesn't work out
well if we want to have an apply function, which we do want, because it
makes more sense if we want to resolve such a device specification
without using builtins.match all over the place.

It also improves a lot in readability of the option descriptions,
because every such option now has not only a description of what a
device specification is but also lists the valid types for the device
specification.

This has another advantage that instead for something like the
following:

Type: list of device specification of <type>.<name>s

The type description is now just:

Type: list of device specifications

We're also heading for more consistency, speaking about "device
specification" or shortly "devspec". Say if we have something like
"storage.foo.bar", "foo.bar" is the "device specification" and "foo" is
the "device specification type" and "bar" is the "device specification
name".

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

So far we passed the device specification as-is to nixpart, but from
within the module system it's quite tricky to validate or look up such a
string, because we need to parse it every time we need to do a look up
an a configuration value in "storage.*".

Now a device specification is an attribute set consisting of a `name'
and a `type' attribute. We also have a new applyTypeContainer attribute
we need to pass to mkDeviceSpecOption so that we can properly convert
things such as "listOf devspecType" into a list of valid internal
representations of device specifications.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

This is handy if we want to look up configuration options for a specific
device specification, so with only the internal representation of a
devspec we can simply say devspec.uuid to get a generated UUID.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

This implements the deterministically generated UUIDs to be used while
mounting file systems, but only if there is no label set already. So the
user still has a way to set labels (which are also applied by nixpart)
and use them accordingly, even though the UUIDs should be more
distincive.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

While it may be handy to put the whole configuration of the
corresponding device specification into the values of the options
referring to them, this unfortunately blows up the size of the JSON
output we pass to nixpart.

This is unnecessary because we're only interested in the UUID.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

I'm heading for a hybrid approach (using UUIDs and partition layout
holes) in nixpart for achieving storage tree determinism, so we need to
have support for setting UUIDs. Blivet currently doesn't yet support
this, so I've implemented it.

Upstream pull request:

storaged-project/blivet#537

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

These tools are needed in order to run tests for NTFS and for setting
the serial of a FAT file system after it has been created.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

Even though the ntfs3g utilities are available inside our test
environment, the format didn't get advertised as formattable because the
_formattable attribute wasn't set to True.

Submitted upstream at:

storaged-project/blivet#536

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

Switches to using a dictionary for devspecs and supports setting UUIDs
for every device specification (currently only sets RFC4122-style
UUIDs).

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

We no longer need to use labels now that every file system gets assigned
an UUID in latest nixpart.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>