[RFC PATCH v8 00/23] Modernize U-Boot shell
Peter Robinson
pbrobinson at gmail.com
Sat May 13 11:54:10 CEST 2023
On Fri, May 12, 2023 at 9:04 PM Francis Laniel
<francis.laniel at amarulasolutions.com> wrote:
>
> Hi.
>
>
> During 2021 summer, Sean Anderson wrote a contribution to add a new shell, based
> on LIL, to U-Boot [1, 2].
> While one of the goals of this contribution was to address the fact actual
> U-Boot shell, which is based on Busybox hush, is old there was a discussion
> about adding a new shell versus updating the actual one [3, 4].
>
> So, in this series, with Harald Seiler, we updated the actual U-Boot shell to
> reflect what is currently in Busybox source code.
> Basically, this contribution is about taking a snapshot of Busybox shell/hush.c
> file (as it exists in commit 37460f5da) and adapt it to suit U-Boot needs.
>
> This contribution was written to be as backward-compatible as possible to avoid
> breaking the existing.
> So, the 2021 hush flavor offers the same as the actual, that is to say:
> 1. Variable expansion.
> 2. Instruction lists (;, && and ||).
> 3. If, then and else.
> 4. Loops (for, while and until).
> No new features offered by Busybox hush were implemented (e.g. functions).
What sort of impact does this have on firmware sizes?
> It is possible to change the parser at runtime using the "cli" command:
> => cli print
> old
> => cli set 2021
> => cli print
> 2021
> => cli set old
> The default parser is the old one.
> Note that to use both parser, you would need to set both CONFIG_HUSH_2021_PARSER
> and CONFIG_HUSH_OLD_PARSER.
>
> In terms of testing, new unit tests were added to ut to ensure the new behavior
> is the same as the old one and it does not add regression.
> Nonetheless, if old behavior was buggy and fixed upstream, the fix is then added
> to U-Boot [5].
> In sandbox, all of these tests pass smoothly:
> => printenv board
> board=sandbox
> => ut hush
> Running 20 hush tests
> ...
> Failures: 0
> => parser set 2021
> => ut hush
> Running 20 hush tests
> ...
> Failures: 0
>
> Thanks to the effort of Harald Seiler, I was successful booting a board:
> => printenv fdtfile
> fdtfile=amlogic/meson-gxl-s905x-libretech-cc.dtb
> => cli get
> old
> => boot
> ...
> root at lepotato:~#
> root at lepotato:~# reboot
> ...
> => cli set 2021
> => cli get
> 2021
> => printenv fdtfile
> fdtfile=amlogic/meson-gxl-s905x-libretech-cc.dtb
> => boot
> ...
> root at lepotato:~#
>
> I was able to have the CI passes but I had to not use CONFIG_HUSH_2021_PARSER
> for the keymile board.
> Indeed, the keymile board family is the only set of boards to call
> get_local_var(), set_local_var() and unset_local_var().
> Sadly, these functions are static in this contribution.
> I could have change all of them to introduce code like this:
> *_local_var(/*...*/)
> {
> if (gd->flags & GD_FLG_HUSH_OLD_PARSER)
> return *_local_var_old(/*...*/);
> if (gd->flags & GD_FLG_HUSH_2021_PARSER)
> return *_local_var_2021(/*...*/);
> }
> But this would have mean renaming all old hush functions calls and I did not
> want to change the old hush particularly to avoid breaking things.
> Instead, I change the keymile board to use environment variable instead of local
> ones.
> I think this particularities can be addressed in future works.
>
> I also had to enable CONFIG_LTO for kirkwoord sheevaplug and phytec bk4r1, so
> they do not hit their limits.
>
> For all these reasons, I marked this contribution as RFC to indeed collect your
> opinions.
> My goal is not to change suddenly actual shell to this one, we clearly need a
> transition period to think about it.
> I think it is better to see this contribution as a proof of concept which shows
> it is possible to update the actual shell.
>
> If you want to review it - your review will really be appreciated - here are
> some information regarding the commits:
> * commits marked as "test:" deal with unit tests.
> * commit "cli: Add Busybox upstream hush.c file." copies Busybox shell/hush.c
> into U-Boot tree, this explain why this commit contains around 12000 additions.
> * commit "cli: Port Busybox 2021 hush to U-Boot." modifies previously added file
> to permit us to use this as new shell.
> The really good idea of #include'ing Busybox code into a wrapper file to define
> some particular functions while minimizing modifications to upstream code comes
> from Harald Seiler.
> * commit "cmd: Add new parser command" adds a new command which permits
> selecting parser at runtime.
> I am not really satisfied with the fact it calls cli_init() and cli_loop() each
> time the parser is set, so your reviews would be welcomed.
> * Other commits focus on enabling features we need (e.g. if).
>
> Changes since:
> v2:
> * Added a small fix to compile sandbox with NO_SDL=1.
> * Added a command to change parser at runtime.
> * Added 2021 parser function to all run_command*().
> v3:
> * Various bug fixes pointed by the CI.
> * Added upstream busybox hush commits until 6th February 2022.
> v4:
> * Various cleaning.
> * Modified python test to accept failure output when the test are designed to
> fail.
> * Bumped upstream busybox hush commits until 24h March 2022.
> v5:
> * Bumped upstream busybox hush commits until 30th January 2023.
> * Fix how hush interprets '<' and '>', indeed we needed to escape them but I
> removed this behavior as tests are handled by test command and not hush
> itself. This permitted to have the ut fdt to pass.
> * Fix a problem with how exit was handled. This was reported by the ut exit
> test.
> v6:
> * There was no v6 and I got mixed up with version.
> v7:
> * Bumped upstream busybox hush commits until 9th May 2023.
> * Renamed parser command to change parser at runtime to cli and added
> documentation.
> * Added better separation of patches.
> * Removed code about __gnu_thumb1_case_si as it was merged in another series.
> * Various cleaning.
>
> Francis Laniel (23):
> test: Add framework to test hush behavior
> test: hush: Test hush if/else
> test/py: hush_if_test: Remove the test file
> test: hush: Test hush variable expansion
> test: hush: Test hush commands list
> test: hush: Test hush loops
> cli: Add Busybox upstream hush.c file
> cli: Port Busybox 2021 hush to U-Boot
> cli: Add menu for hush parser
> global_data.h: add GD_FLG_HUSH_OLD_PARSER flag
> cmd: Add new cli command
> cli: Enables using hush 2021 parser as command line parser
> cli: hush_2021: Enable variables expansion for hush 2021
> cli: hush_2021: Add functions to be called from run_command()
> cli: add hush 2021 as parser for run_command*()
> test: hush: Fix instructions list tests for hush 2021
> test: hush: Fix variable expansion tests for hush 2021
> cli: hush_2021: Enable using < and > as string compare operators
> cli: hush_2021: Enable if keyword
> cli: hush_2021: Enable loops
> test: hush: Fix loop tests for hush 2021
> cli: hush_2021: Add upstream commits up to 9th May 2023.
> DO NOT MERGE: only to make CI happy
>
> cmd/Kconfig | 22 +
> cmd/Makefile | 2 +
> cmd/cli.c | 125 +
> common/Makefile | 3 +-
> common/cli.c | 82 +-
> common/cli_hush_2021.c | 306 +
> common/cli_hush_upstream.c | 13021 +++++++++++++++++++++++++++
> configs/sheevaplug_defconfig | 1 +
> doc/usage/cmd/cli.rst | 74 +
> doc/usage/index.rst | 1 +
> include/asm-generic/global_data.h | 8 +
> include/cli_hush.h | 51 +-
> include/test/hush.h | 15 +
> include/test/suites.h | 1 +
> test/Makefile | 3 +
> test/cmd_ut.c | 6 +
> test/hush/Makefile | 10 +
> test/hush/cmd_ut_hush.c | 20 +
> test/hush/dollar.c | 226 +
> test/hush/if.c | 316 +
> test/hush/list.c | 140 +
> test/hush/loop.c | 91 +
> test/py/tests/test_hush_if_test.py | 197 -
> test/py/tests/test_ut.py | 8 +-
> tools/patman/series.py | 4 +
> 25 files changed, 14521 insertions(+), 212 deletions(-)
> create mode 100644 cmd/cli.c
> create mode 100644 common/cli_hush_2021.c
> create mode 100644 common/cli_hush_upstream.c
> create mode 100644 doc/usage/cmd/cli.rst
> create mode 100644 include/test/hush.h
> create mode 100644 test/hush/Makefile
> create mode 100644 test/hush/cmd_ut_hush.c
> create mode 100644 test/hush/dollar.c
> create mode 100644 test/hush/if.c
> create mode 100644 test/hush/list.c
> create mode 100644 test/hush/loop.c
> delete mode 100644 test/py/tests/test_hush_if_test.py
>
>
> Best regards and thank you in advance.
> ---
> [1] https://lists.denx.de/pipermail/u-boot/2021-July/453347.html
> [2] https://runtimeterror.com/tech/lil/
> [3] https://lists.denx.de/pipermail/u-boot/2021-July/453790.html
> [4] https://lists.denx.de/pipermail/u-boot/2021-July/453848.html
> [5] https://lists.denx.de/pipermail/u-boot/2021-August/458569.html
> --
> 2.34.1
>
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