MFC r306325, r306329-r306330, r306333, r306620-r306622, r307544, r307550, r318137, r319125, r319295

r306325 by marcel:
Replace the use of linker sets with constructors for both the
formats and schemes. Formats and schemes are registered at
runtime now, rather than collected at link time.

r306329 by marcel:
Eliminate the use of EDOOFUS. The error code was used to signal
programming errors, but is really a poor substitute for assert.
And less portable as well.

r306330 by marcel:
Avoid depending on the <sys/endian.h> header for le*enc and be*enc.
Not only is the header unportable, the encoding/decoding functions
are as well. Instead, duplicate the handful of small inlines we
need into a private header called endian.h.

Aside: an alternative approach is to move the encoding/decoding
functions to a separate system header. While the header is still
nonportable, such an approach would make it possible to re-use the
definitions by playing games with include paths. This may be the
preferred approach if more (build) utilities need this. This
change does not preclude that. In fact, it makes it easier.

r306333 by marcel:
Portability changes:
1. macOS nor Linux have MAP_NOCORE nor MAP_NOSYNC. Define as 0.
2. macOS doesn't have SEEK_DATA nor SEEK_HOLE. Define as -1
so that lseek will return -1 (with errno set to EINVAL).
3. gcc correctly warns that error is assigned but not used in
image_copyout_region(). Fix by returning on the first error.

r306620 by marcel:
Replace STAILQ with TAILQ. TAILQs are portable enough that they can
be used on both macOS and Linux. STAILQs are not. In particular,
STAILQ_LAST does not next on Linux. Since neither STAILQ_FOREACH_SAFE
nor TAILQ_FOREACH_SAFE exist on Linux, replace its use with a regular
TAILQ_FOREACH. The _SAFE variant was only used for having the next
pointer in a local variable.

r306621 by marcel:
Prefer <stdint.h> over <sys/types.h>. While here remove redundant
inclusion of <sys/queue.h>.

Move the inclusion of the disk partitioning headers out of order
and inbetween standard headers and local header. They will change
in a subsequent commit.

r306622 by marcel:
Replace OFF_MAX with INT64_MAX. The former is defined on Linux.

r307544 by marcel:
o Provide a private definition for UUIDs (mkimg_uuid_t) because
UUIDs are not portable.
o Move mkimg_uuid() to a new file and merge both gpt_uuid_enc()
and vhd_uuid_enc() into a single mkimg_uuid_enc() that lives
in the same file.
o Move the OS-specific implementation of generating a UUID to
osdep_uuidgen() and provide the implementations for FreeBSD,
macOS and Linux.
o Expect the partitioning scheme headers to be found by having
a search to the directory in which the headers live. This
avoids conflicts on non-FreeBSD machines.

r307550 by imp:
Add a new flag to mkimg (-a num) to specify the active partition for
those partitioning schemes that have this concept. Implement it as an
override for mbr's setting 0x80 in the flags for the first partition
when we have boot code.

Differential Revision: https://reviews.freebsd.org/D4403

r318137:
mkimg: Add -C argument to specify maximum capacity

Add a -C option to specify a maximum capacity for the final image file.
It is useful to control the size of the generated image for sdcard or
when we will add dynamic size partition.

Add --capacity which is a shorthand to define min and max capacity at
the same time.

Reviewed by: bapt, marcel, wblock (manpages)
Sponsored by: Gandi.net
Differential Revision: https://reviews.freebsd.org/D10509

r319125:
mkimg: Correct an off by one error in the PMBR size

The PMBR last sector should be number of sector - 1 (As stated in UEFI Spec
2.6 page 118 table 17).
This fixes warning printed by linux tools like parted or fdisk.

Sponsored by: Gandi.net

r319295 by ngie:
Update the usr.bin/mkimg golden test output files after ^/head@r319125

^/head@r319125 changed the location of the backup pmbr, requiring the
output files to be regenerated, since they're binary disk dumps.

The output files were regenerated with "make rebase"--fixed in
^/head@r319294.

MFC with: r319125, r319294
PR: 219673
Sponsored by: Dell EMC Isilon

Revert r328974, r307387 was not supposed to be part of it.

MFC r306325, r306329-r306330, r306333, r306620-r306622, r307387, r307544, r307550, r318137, r319125, r319295

r306325 by marcel:
Replace the use of linker sets with constructors for both the
formats and schemes. Formats and schemes are registered at
runtime now, rather than collected at link time.

r306329 by marcel:
Eliminate the use of EDOOFUS. The error code was used to signal
programming errors, but is really a poor substitute for assert.
And less portable as well.

r306330 by marcel:
Avoid depending on the <sys/endian.h> header for le*enc and be*enc.
Not only is the header unportable, the encoding/decoding functions
are as well. Instead, duplicate the handful of small inlines we
need into a private header called endian.h.

Aside: an alternative approach is to move the encoding/decoding
functions to a separate system header. While the header is still
nonportable, such an approach would make it possible to re-use the
definitions by playing games with include paths. This may be the
preferred approach if more (build) utilities need this. This
change does not preclude that. In fact, it makes it easier.

r306333 by marcel:
Portability changes:
1. macOS nor Linux have MAP_NOCORE nor MAP_NOSYNC. Define as 0.
2. macOS doesn't have SEEK_DATA nor SEEK_HOLE. Define as -1
so that lseek will return -1 (with errno set to EINVAL).
3. gcc correctly warns that error is assigned but not used in
image_copyout_region(). Fix by returning on the first error.

r306620 by marcel:
Replace STAILQ with TAILQ. TAILQs are portable enough that they can
be used on both macOS and Linux. STAILQs are not. In particular,
STAILQ_LAST does not next on Linux. Since neither STAILQ_FOREACH_SAFE
nor TAILQ_FOREACH_SAFE exist on Linux, replace its use with a regular
TAILQ_FOREACH. The _SAFE variant was only used for having the next
pointer in a local variable.

r306621 by marcel:
Prefer <stdint.h> over <sys/types.h>. While here remove redundant
inclusion of <sys/queue.h>.

Move the inclusion of the disk partitioning headers out of order
and inbetween standard headers and local header. They will change
in a subsequent commit.

r306622 by marcel:
Replace OFF_MAX with INT64_MAX. The former is defined on Linux.

r307387 by marcel:
Switch to using the portable partition scheme headers.

r307544 by marcel:
o Provide a private definition for UUIDs (mkimg_uuid_t) because
UUIDs are not portable.
o Move mkimg_uuid() to a new file and merge both gpt_uuid_enc()
and vhd_uuid_enc() into a single mkimg_uuid_enc() that lives
in the same file.
o Move the OS-specific implementation of generating a UUID to
osdep_uuidgen() and provide the implementations for FreeBSD,
macOS and Linux.
o Expect the partitioning scheme headers to be found by having
a search to the directory in which the headers live. This
avoids conflicts on non-FreeBSD machines.

r307550 by imp:
Add a new flag to mkimg (-a num) to specify the active partition for
those partitioning schemes that have this concept. Implement it as an
override for mbr's setting 0x80 in the flags for the first partition
when we have boot code.

Differential Revision: https://reviews.freebsd.org/D4403

r318137:
mkimg: Add -C argument to specify maximum capacity

Add a -C option to specify a maximum capacity for the final image file.
It is useful to control the size of the generated image for sdcard or
when we will add dynamic size partition.

Add --capacity which is a shorthand to define min and max capacity at
the same time.

Reviewed by: bapt, marcel, wblock (manpages)
Sponsored by: Gandi.net
Differential Revision: https://reviews.freebsd.org/D10509

r319125:
mkimg: Correct an off by one error in the PMBR size

The PMBR last sector should be number of sector - 1 (As stated in UEFI Spec
2.6 page 118 table 17).
This fixes warning printed by linux tools like parted or fdisk.

Sponsored by: Gandi.net

r319295 by ngie:
Update the usr.bin/mkimg golden test output files after ^/head@r319125

^/head@r319125 changed the location of the backup pmbr, requiring the
output files to be regenerated, since they're binary disk dumps.

The output files were regenerated with "make rebase"--fixed in
^/head@r319294.

MFC with: r319125, r319294
PR: 219673
Sponsored by: Dell EMC Isilon

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add ppcboot FAT type. Needed to create a bootable powerpc image.

Differential Review: https://reviews.freebsd.org/D4407

mkimg: support fat16b partitions (MBR type 06h)

Reviewed by: marcel
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3894

Add the ntfs alias and support it with the MBR and GPT schemes
as DOSPTYP_NTFS and GPT_ENT_TYPE_MS_BASIC_DATA (resp).

Don't require a scheme if no partitions are given. Change the code
to handle that case. Note that we still require partitions, so the
change is effectively a no-op.

In scheme_write(), don't overwrite the end parameter with the
return value of image_get_size(). As it so happens, the only
caller of scheme_write() passes exactly that.

Fix partition alignment and image rounding when any of -P (block size),
-T (track size) or -H (number of heads) is given:
o scheme_metadata() always rounded to the block size. This is not
always valid (e.g. vtoc8 that must have partitions start at cylinder
boundaries).
o The bsd and vtoc8 schemes "resized" the image to make it match the
geometry, but since the geometry is an approximation and the size
of the image computed from cylinders * heads * sectors is always
smaller than the original image size, the partition information ran
out of bounds.

The fix is to have scheme_metadata() simply pass it's arguments to the
per-scheme metadata callback, so that schemes not only know where the
metadata is to go, but also what the current block address is. It's now
up to the per-scheme callback to reserve room for metadata and to make
sure alignment and rounding is applied.

The BSD scheme now has the most elaborate alignment and rounding. Just
to make the point: partitions are aligned on block boundaries, but the
image is rounded to the next cyclinder boundary.

vtoc8 now properly has all partitions aligned (and rounded) to the
cyclinder boundary.

Obtained from: Juniper Networks, Inc.
MFC after: 3 days

Fix CID 1215125: fstat(2) returns -1 on error and sets errno. It does
not return the error (oops).

MFuser/marcel/mkimg:
Add support for different output formats:
1. The output file that was previously written is now called the raw format.
2. Add the vmdk output format to create VMDK images.

When the format is not given, the raw output format is assumed.

Add mkimg, a utility for making disk images from raw partition contents.
The partitioning scheme can be one of the schemes supported by gpart.

Reviewed by: sjg
Obtained from: Juniper Networks, Inc.

Remember operator precedence?

1. When calculating block addresses, round to the physical block
size.
2. Replace scheme_first_block() & scheme_next_block() with
scheme_metadata(). When we round to block sizes, we can't
reliably fixup any miscalculations.
3. In scheme_write, calculate ncyls (number of cyclinders), based
on the total size, sectors/track and number of heads.
4. Add verbosity when constructing the partitions. This includes
the starting block address and size in bytes and blocks.
5. Add verbosity about the sectors/track and number of heads.

Add scheme_max_secsz() for returning the maximum sector size supported
by the partitioning scheme.

Add the fat32 and ebr aliases. The ebr alias is needed to support
the EBR scheme, as it can only live inside a MBR partition of type
5 (= DOSPTYP_EXT).

Revamp:
1. Make secsz globally visible.
2. Have all code use the global secsz and nparts, rather than passing
them around.
3. Introduce lba_t as the type to use when talking about block addresses.
4. Work on LBAs instead of offsets. There's just too much division with
the sector size and there's really no value to use by offsets other
than that is what lseek() wants. For that we now have mkimg_seek().

The bigger picture is that geometry (cylinders, heads, sectors/track) and
also a possible physical sector size are to be globals that can be used
from anyway. We really don't want to pass all that stuff as arguments to
functions and then add __unused for most of them...

Handle the -b option for specifying boot code that lives in the
partitioning scheme's meta data. Implement it for GPT.

Add more partition types (mostly just the FreeBSD ones) to GPT.
Avoid having schemes use literal strings by introducing an enum
as the intermediate representation (see geom_part).

Add support for partition labels and write them for GPT.

Dump my WIP of write support for GPT. This compiles, appears to be
complete, but isn't accepted by g_part_gpt. Time to debug and fix.

Add a scheme-specific write callback to write the metadata.
While here:
1. Move FreeBSD-specific headers to a more centralized place, so that
it's easier to port mkimg.
2. Remove inclusion of <uuid.h> where we don't need it (copy-pasted).
3. Check the partition data given on the command line before we do any
I/O.
4. Add scheme_round() for rounding the partition size.
5. Have scheme_write call the scheme-specific write callback and have
it propagate errors back to the caller.

Replace *_get_leader() and *_get_trailer() with a single *_metadata().
This single function takes a where argument to indicate the kind of
metadata to "size". This way we can also get rid of the "padding"
field in the scheme structure.
This should make it a little more understandable what's going on.

Check the partition type alias as defined by the scheme.

Use linker sets to provide build-time selection of the schemes
that need to be supported. Each scheme provides data and callbacks
for handling the scheme-specifics.
To this end, put each scheme in its own source file.

Add mkimg.h. It contains the 'part' structure definition and the linked
list (STAILQ) so that it can be shared and re-used in all source files.
Replace the now unneeded scheme_add_part() with scheme_check_part() for
posterity.

Also (should have been a separate commit), remove the enforcement of
creating a GPT table with at least 128 entries. While this is generally
advised as the default or minimum, it's not actually a hard requirement.
We now recreate a table that's precisely enough (rounded of course).

WHile

Now that we can include <sys/diskpc98.h> and <sys/diskmbr.h> at
the same time withiut conflict, use the constants defined in them.

Safe WIP: mkimg is a user-space utility for creating disk images.
In its current form and shape, it creates images with the correct
partition contents and overall image layout. What it doesn't do
yet is actually scribble the metadata, such as partition tables
and boot code. This is where I'd like to leverage code from other
places, such as geom_part, and if possible/feasible.
Also, the utility should be a little bit smarter about files and
pipes so that we create temporary files only when needed (e.g.
when we don't know the size of a partition's contents in advance
while wrting the image to stdout).