doc: Give an example with a FAT UUID.

* gnu/system/examples/lightweight-desktop.tmpl <file-systems>: Add a
UUID for the /boot/efi partition.
* doc/guix.texi (Using the Configuration System): Mention it.

uuid: Change "fat32" to "fat".

* gnu/system/uuid.scm (%fat32-endianness): Rename to...
(%fat-endianness): ... this.
(fat32-uuid->string): Rename to...
(fat-uuid->string): ... this.
(%fat32-uuid-rx): Rename to..
(%fat-uuid-rx): ... this.
(string->fat32-uuid): Rename to...
(string->fat-uuid): ... this.
(%uuid-parsers, %uuid-printers): Add 'fat16.

file-systems: Preserve UUID types when serializing.

Reported by Roel Janssen <roel@gnu.org>
at <https://lists.gnu.org/archive/html/help-guix/2017-09/msg00094.html>.

* gnu/system/file-systems.scm (file-system->spec): When DEVICE is a
UUID, serialize it in a way that preserves its type.
(spec->file-system): Adjust accordingly.
* gnu/build/file-systems.scm (canonicalize-device-spec): Add case for
when SPEC is 'uuid?'.

file-systems: 'mount-file-system' now takes a <file-system> object.

* gnu/build/file-systems.scm (mount-file-system): Rename 'spec' to 'fs'
and assume it's a <file-system>.
* gnu/build/linux-boot.scm (boot-system): Assume MOUNTS is a list of
<file-system> and adjust accordingly.
* gnu/build/linux-container.scm (mount-file-systems): Remove
'file-system->spec' call.
* gnu/services/base.scm (file-system-shepherd-service): Add
'spec->file-system' call.  Add (gnu system file-systems) to 'modules'.
* gnu/system/linux-initrd.scm (raw-initrd): Use (gnu system
file-systems).  Add 'spec->file-system' call for #:mounts.

linux-initrd: Ensure that the guile used in the initrd is referenced.

By referencing guile from the initrd output explicitly, it will be present in
the store when this initrd is used. If the exact guile used within the initrd
isn't present in the store, then after root is switched during the boot
process, loading modules (such as (ice-9 popen)) won't work.

This fixes guix-patches bug #28399, "Fix mysql activation, and add a basic
test".

* gnu/system/linux-initrd.scm (expression->initrd)[builder]: Write out a file
  called references in to the initrd output, which includes the store path for
  guile.

Merge branch 'master' into staging

file-systems: Add a 'location' field to <file-system>.

* gnu/system/file-systems.scm (<file-system>)[location]: New field.

uuid: Add 'uuid=?' and use it.

* gnu/system/uuid.scm (uuid=?): New procedure.
* tests/uuid.scm ("uuid=?"): New test.
* gnu/build/file-systems.scm (partition-uuid-predicate)
(luks-partition-uuid-predicate): Use it instead of 'bytevector=?'.

Merge branch 'master' into staging

vm: Add disk-image-size to <virtual-machine>.

* gnu/system/vm.scm (<virtual-machine>): Add disk-image-size.
  (port-forwardings->qemu-options): Use disk-image-size from
  <virtual-machine>.

vm: Add a minimum root size.

* gnu/system/vm.scm (qemu-image): When guessing the root-size, use a lower
  bound of 20 MiB, otherwise the root file system size is sometimes 0 MiB in
  size.

Merge branch 'master' into staging

uuid: Add a parser for FAT32 UUIDs.

* gnu/system/uuid.scm (%fat32-uuid-rx): New variable.
(string->fat32-uuid): New procedure.
(%uuid-parsers): Add it.
* tests/uuid.scm ("uuid, FAT32, format preserved"): New test.

services: Move 'session-environment-service-type' to pam.scm.

* gnu/services/base.scm (environment-variables->environment-file)
(session-environment-service-type)
(session-environment-service): Move to...
* gnu/system/pam.scm: ... here.

Merge branch 'master' into staging

doc: Use Screen and OpenSSH in the bare-bones example.

* gnu/system/examples/bare-bones.tmpl (packages): Remove TCPDUMP; add
SCREEN and OPENSSH.
* doc/guix.texi (Using the Configuration System): Adjust explanation
accordingly.

install: Include the whole bare-bones OS in the image.

* gnu/system/install.scm (%installation-services): Load
"example/bare-bones.tmpl".  Add a 'gc-root-service-type' instance.

vm: Generate a UUID to identify the root file system.

This makes collisions less likely than when using a label to look up the
partition.  See <https://bugs.gnu.org/27735>.

* gnu/system/vm.scm (operating-system-uuid): New procedure.
(system-disk-image): Define 'root-uuid' and use it for the root file
system.  Pass it to 'iso9660-image' and 'qemu-image'.

vm: Allow users to specify a UUID for the root partition.

* gnu/system/vm.scm (qemu-image): Add #:file-system-uuid parameter; pass
it as the 'uuid' field of the root partition.

uuid: 'uuid' macro supports more UUID types.

* gnu/system/uuid.scm (string->uuid): Turn 'type' into an optional
argument.
(uuid): Add clauses to allow for an optional 'type' parameter.