On Fri, Dec 08, 2023 at 11:30:01PM +0100, Francis Laniel 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 modern 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 modern > => cli print > modern > => cli set old > The default parser is the old one. > Note that to use both parser, you would need to set both > CONFIG_HUSH_MODERN_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 > => cli set modern > => 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@lepotato:~# > root@lepotato:~# reboot > ... > => cli set modern > => cli get > modern > => printenv fdtfile > fdtfile=amlogic/meson-gxl-s905x-libretech-cc.dtb > => boot > ... > root@lepotato:~# > > This contribution indeed adds a lot of code and there were concern about its > size [6, 7]. > With regard to the amount of code added, the cli_hush_upstream.c is 13030 > lines > long but it seems a smaller subset is really used: > gcc -D__U_BOOT__ -E common/cli_hush_upstream.c | wc -l > 2870 > Despite this, it is better to still have the whole upstream code for the sake > of > easing maintenance. > With regard to memory size, I conducted some experiments for version 8 of this > series and for a subset of arm64 boards and found the worst case to be 4K [8]. > Tom Rini conducted more research on this and also found the increase to be > acceptable [9]. > > 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. > v11: > * Renamed everything containing 2021 to modern. > * Fixed cmd Kconfig indentation. > * Set modern parser as default for majority of boards except some.
Thanks, this looks good overall and I'll put things in CI soon and aim to get this in to -next and v2024.04. -- Tom
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