[PATCH v11 00/24] Modernize U-Boot shell
Simon Glass
sjg at chromium.org
Thu Nov 9 02:15:26 CET 2023
Hi Peter,
On Wed, 8 Nov 2023 at 05:14, Peter Robinson <pbrobinson at gmail.com> wrote:
>
> On Wed, Nov 8, 2023 at 12:49 AM 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).
> >
> > 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 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.
>
> With nearly 15K lines of code added and the above limits being reached
> how much does this increase the size of a binary if it's selected?
> Those sorts of details are useful in these cover letters. Also of the
> 13k lines in cli_hush_upstream.c how much of that functionality is
> actually used in U-Boot? You mention functions are not, while I
> understand adding it straight from busybox has it's advantages for
> easier rebasing, if it's also pulling in a lot of code that is never
> used there's also detractions to adding 13k lines of code.
Yes it would be good to have this in the cover letter. I did some
analysis of 10 and it seemed to be about 3KB[1] which is great!
It is helpful to have the code be similar to busybox, since then we
can apply patches from upstream easily. Of course there are
trade-offs, but the decisions in this series make sense to me. It may
be possible to upstream some of the feature control, but I wouldn't
bank on it.
>
> > 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.
> > v8:
> > * Bumped upstream busybox hush commits until 25th May 2023.
> > v9:
> > * Bumped upstream busybox hush commits until 2nd October 2023.
> > v10:
> > * Fixed a build error in commit adding cli command.
> > * Add new CONFIG_HUSH_SELECTABLE to only build cli command if the two shell
> > flavors are selected.
> >
> > Francis Laniel (24):
> > 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 2nd October 2023.
> > DO NOT MERGE: only to make CI happy
> > DO NOT MERGE: ci: Build the world in any case.
> >
> > .azure-pipelines.yml | 1 +
> > cmd/Kconfig | 26 +
> > cmd/Makefile | 2 +
> > cmd/cli.c | 134 +
> > common/Makefile | 3 +-
> > common/cli.c | 82 +-
> > common/cli_hush_2021.c | 324 +
> > common/cli_hush_upstream.c | 13030 +++++++++++++++++++++++++++
> > 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 +
> > 26 files changed, 14563 insertions(+), 211 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
> >
[1] https://patchwork.ozlabs.org/project/uboot/cover/20231004164220.15738-1-francis.laniel@amarulasolutions.com/
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