[bootloader] handle loading zircon image from partition

- identify which block device the bootloader was loaded from
- check first type-guid==zircon-a partition for a valid image
- prefer that image (if present) over zircon.bin in EFI/FAT
- update gpt commandline tool to know about zircon-a, etc types

Test: verified operation on actual hw by swetland and raggi

Change-Id: I8eeb24c0ab03ee54f086a2619718daa9d0011b6e

[cprng] Update clients to zx_cprng_draw

Test: cprng, chromeos-disk-setup
Change-Id: I8fffa468ceec58a371c8eaa0c6bbdaa204e77df8

[cprng] Remove short reads from zx_cprng_draw

We never actually generate short reads from zx_cprng_draw. This CL
removes the |actual| out parameter. Now zx_cprng_draw either fails or
succeeds in drawing the amount requested, simplifying clients and
removing possible mistakes.

This CL is phase 1 of the transition, which introduces the new version as
zx_cprng_draw_new. Once all the clients are migrated, we'll change
zx_cprng_draw itself, migrate all the clients back, and then remove
zx_cprng_draw_new.

Change-Id: I2219d0517f103fb999014de1e846fa8b8a5ca20c

[public][ulib][dev] Add __FALLTHROUGH macro for warning suppression

GCC 7 enables -Wimplicit-fallthrough with -Wextra, so we'll get it.
Clang has it available, so start using it and clean up code accordingly.

The GCC feature will actually recognize some formulaic comments to
suppress the warning. But there's also an explicit syntax, and
C++17 added a standard one. So use that instead, via the new macro
__FALLTHROUGH in <zircon/compiler.h>.

TC-36 #comment Clean up code in preparation for more -Wimplicit-fallthrough

Change-Id: I28309c91c32db1313d52f4255836c5ea687e141f

[blobstore] Rename blobstore to blobfs

Also, mount blobfs at /blob rather than /blobstore.

Change-Id: Ifdc473752ede37b909b30e35dbaac1397565a659

[gpt][minfs] add installer partition type

This partition type GUID is auto-mounted at /install and will be used by
installer USB keys and such use cases, maybe recovery.

Change-Id: I959c462182285d39b9d8943a8d785857aa7880a1

[gpt] Consolidate c-string / UTF-16 conversion

Change-Id: Ic3c801ce8d5f22ae2d9c7e22254387a2bf427105

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[gpt] improve quality of life

- show new partition table before confirmation prompt
- highlight modified fields in new partition table
- add gpt_get_diffs() to library to enable the above
- wait at confirmation prompt until y/n/ESC pressed
- add "adjust" command to move or resize partitions
- add "--live-dangerously" initial option to override
confirmation prompt for those who are very sure

Change-Id: I90e470c44053ee64f283a7ed88dc7e627b08f783

[gpt] Implement modifying CrOS kernel GPT flags

This lets us set the successful, priority, and tries values.

Change-Id: I491d7bb6f80a3271cbd39120fc2f51487b0d242f

[gpt] Add support for using CrOS partition attributes

This adds library support for getting/setting the attributes, and
updates the gpt command to dump them.

Change-Id: I0f4d68de416331c7b4e8f1e80e9cfb5df2df6540

[uapp][status] Use the new MX_OK and MX_ERR_* mx_status_t names

Change-Id: Iaa8c8c12736e49d202c33612b22d2acd528fcf2d

[uapp][gpt] Make "gpt init" clear existing GPT partition maps

"gpt init" was able to create new gpt partition maps where none
existed before, but was not actually reinitializing existing
partition maps.

Change-Id: Ie2dbabc65d32a8e9076e730f13560648a3b2c2a3

[app][gpt] fix repartition command to not fail if there are no existing partitions

Change-Id: Ica3dbd490c9947bb05e0924d7f0408b97dfc7ac0

[udev][sata] support scatter/gather

Support discontiguous iotxns and increase the PRD table size to 8k,
so the maximum worst-case transfer size is 32M for a fully
distiguous iotxn. Add a field in block_info_t to return this info.

Change-Id: I68f3cf6c25ca2d2cbe709768bfa43e1fc20e300e

[gpt] add easy repartition command

example usage:

gpt repartition /dev/class/block-core/000 esp efi 100m sys system 1g data data 100%

Change-Id: I8e8c7f59512f6c9f2ee188afc000ad7bb71e6e21

[block] Convert BLOCK SIZE ioctls to GET_INFO

MG-709 #done

Change-Id: I96a7ca110a1e33eded5e6a2ee2535131c7b7ade6

[gpt] add blobfs support to gpt tool

Change-Id: Ib995c0eda698c696d228841e47e1b88c934f491a

[gpt] Make GPT tool more usable; update MinFS instructions

- Remove the "Default block device". On real hardware, magically
updating a potentially random device is a recipe for disaster.
- Add operation to ulib/gpt to query usable range of GPT, so user
does not need to calculate size of metadata themselves.
- Add operation to uapp/gpt to initialize empty gpt, so the range of
the GPT may subsequently be queried.
- Improve uapp/gpt usage description to document tool.
- Update uapp/gpt tool to print all block ranges in decimal,
not hex.
- Update uapp/gpt to add partitions by range (start, end), matching
the range presented by the "dump" command.
- Update MinFS instructions to use less "magic" (no assumptions about
underlying block size), and use the new GPT instructions.

Change-Id: Idbb9f6104d0f9b9d8d6efd685686a29a4e4f7e82

[gpt] Check result of mx_cprng_draw call

Change-Id: I67833eeff3b5df151f9ef813cc0e5fd30f221611

[uapp][gpt] Add some keywords for well-known GUIDs

Recognize keywords for efi, system, and data.

Change-Id: I0818a253b1087ea4ce1c01643eccb5c89aabd3f2

Remove mx_size_t and mx_ssize_t types

mx_ssize_t is no longer used. mx_size_t is superfluous and
can be replaced by the standard C type size_t.

Change-Id: I2137af6f166099d2e8aaca4fab63ff101f2a43ac

[app] [gpt] Fix up little issues in 15713

Change-Id: I961f45024d3c28873356d8adc66e3d09356c0ba8

[uapp] [gpt] Allowing partition hiding from EFI

Change-Id: I1c94518dfca668b824f3fa8d7c67d929853757c1

[uapp][gpt] Add ability to edit partition guids in gpt application

This allows the 'gpt' utility to edit the type or ID guids of a
partition in the GPT.
Change-Id: I68f0547f0c737763b0a7a66f4c518d76fe94e83d

[syscalls] update cprng_add_entropy() and cprng_draw()

Change-Id: I59aa8884aa2df2426fb87fe4deeae8846f146cb1

[mxio] Remove most uses of mxio_wait_fd

The two remaining callers can actually have a finite timeout.

Change-Id: I48c4af3604c46af4cb614e36777603c55b46d65e

[userspace] Use PRI?64 macros instead of %ll?

Bug: MG-164

This is the official way to print *int64_t types.

Change-Id: Ib4c7c814a62678650b1691bc1925635235ade217

[gpt] Use ioctl wrappers

Change-Id: I5e17714d70556c123432daf4a76e722d9aba04a4

[magenta] migrate from libddk to magenta/device headers

Change-Id: I91a8df001043635fa595d6fed1a6d6f092fc6b3e

[gpt] print out the guid in the proper byte order

Change-Id: I22ef93d957b99a64f8b3e8ff650e4f01cc00b04c

[magenta][ddk] normalize ioctl defines

- ioctls are now unique
- ioctls now encode a kind, family, and number
- ioctls that return a handle are of IOCTL_KIND_GET_HANDLE
- remoteio plumbing updated to reflect this
- drivers and ioctl users updated

Change-Id: Ic202cec6336a4915b09e3cbfff5dc6389f397288

[udev][sata] implement ioctl to reread partitions

Change-Id: I9ba8a4e4396e3c5f6fe10ba628f616269b5147cd

[system] align license and license banners with Fuchsia

This adjusts the Magenta userspace code to match the prevailing
license in Fuchsia (three-clause BSD), using the same banner
and license text.

Change-Id: I6b6d79435c5dbaa32027888874849e4f47aaa7be

[ulib] add gpt manipulation library and utility

Change-Id: I2f9bb765fd26f97e2e88dc239bc2ab43d6e3af00