state: keep backward compatibility ...

Introduce the new build time option '--enable-state-backward-compatibility' to
port the following barebox commit.

NOTE: This changes barebox-state's default behaviour.

| commit 480cde1
| Author: Juergen Borleis <jbe@pengutronix.de>
| Date:   Tue Aug 15 15:46:31 2017 +0200
|
|     state: keep backward compatibility
|
|     Previous 'state' variable set variants do not know and use metadata. The
|     'direct' storage backend's read function honors this, but not its
|     counterpart the write function. This makes an update of the 'state'
|     variable set impossible.
|     This change makes backward compatibility explicit, else it complains in
|     the read function as well. With some more debug output it helps the
|     developer to do things right.
|
|     Signed-off-by: Juergen Borleis <jbe@pengutronix.de>
|     Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>

state: check length ...

This ports the following barebox commit:

| commit 9271182
| Author: Jan Remmet <j.remmet@phytec.de>
| Date:   Thu May 23 09:49:00 2019 +0200
|
|     common: state: check length
|
|     if written_length is read from a partial written bucket it may be to
|     big and xmalloc will panic barebox.
|
|     Check if the value is sane. Make read_len unsigned to avoid negative
|     values.
|
|     Signed-off-by: Jan Remmet <j.remmet@phytec.de>
|     Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>

state: Fix lseek error check in state_backend_bucket_direct_write() ...

This ports the following barebox commit:

| commit ec25ecf
| Author: Andrey Smirnov <andrew.smirnov@gmail.com>
| Date:   Wed Mar 6 23:49:22 2019 -0800
|
|     state: Fix lseek error check in state_backend_bucket_direct_write()
|
|     Don't use 'int' to store lseek()'s return value to avoid problems with
|     large seek offsets. While at it, make sure to populate return error
|     code from 'errno'.
|
|     Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
|     Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>

state: Fix lseek error check in state_backend_bucket_direct_read() ...

This ports the following barebox commit:

| commit 219b954
| Author: Andrey Smirnov <andrew.smirnov@gmail.com>
| Date:   Wed Mar 6 23:49:21 2019 -0800
|
|     state: Fix lseek error check in state_backend_bucket_direct_read()
|
|     Don't use 'int' to store lseek()'s return value to avoid problems with
|     large seek offsets. While at it, make sure to populate return error
|     code from 'errno'.
|
|     Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
|     Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>

state: Add property to protect existing data ...

This ports the following barebox commit:

| commit 67c1c08
| Author: Daniel Schultz <d.schultz@phytec.de>
| Date:   Thu Apr 12 11:13:01 2018 +0200
|
|     common: state: Add property to protect existing data
|
|     After an update to a newer barebox version with an enabled state
|     framework, existing data in storage memories could be overwritten.
|
|     Add a new property to check in front of every write task, if the meta
|     magic field only contains the magic number, zeros or ones.
|
|     Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
|     Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>
Signed-off-by: Roland Hieber <rhi@pengutronix.de>

state: storage: direct: do not close file that is not opened ...

When open failed to not try to close the invalid fd afterwards.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_bucket_direct: max_size is always given ...

max_size is always != 0, so if(direct->max_size) can be skipped.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend-direct: Fix max_size ...

The max_size in the direct backend includes the meta data, so
substract its size when determing the max data size we can store.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: Convert all bufs to void * ...

A void * is a much better type for a buffer than a u8 * as it
can be casted to any other type implicitly. Convert all buffers
used by the state framework to void *.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: replace len_hint logic ...

The len_hint mechanism is rather hard to understand as it's not clear
from where to where the hint is passed and also it's not clear what
happens if the hint is empty or wrong.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: use packed attribute for on storage structs ...

These structs are used for on-storage data layouts. They should be not
affected by different integer precisions and alignment optimizations of
32bit or 64bit machines. Using the architecture independent integer data
types, like uint32_t, achieves the former, using the packed attribute
the later.

Signed-off-by: Stefan Lengfeld <s.lengfeld@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

barebox-state: Import updated state code ...

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>