[PATCH 0/2] Allow overriding commands

[Glenn Washburn]

This patch series allows user-defined functions to hook commands by creating
a function that is the same name as a command. Commands may be executed by
prefixing the command name with the "builtin" keyword, as in bash. This allows
functions to modify the invocation of commands. For instance, I use this to
concatenate an extra initrd file to an existing one created by my OS, by
hooking initrd and adding the extra file. As an aside, in the future, I'd like
to dynamically generate this extra initrd file within GRUB.

This patch series is not "lockdown" aware. And I'm not entirely sure it needs
to be, but I have a strong suspicion it does. Commands that are locked down
obviously won't all of a sudden work. However, my concern is that this feature
could prevent essential commands from running. Not being entirely familiar with
secureboot, I don't feel I'm in the best position to judge the security
implications . If it is determined that this feature does need to be lockdown
aware, I believe its a fairly simple change, and can modify the patch series.
I'll await feedback before I make that change, as it may be deemed unnecessary.

Glenn

Glenn Washburn (2):
  script: Allow user-defined functions to override builtins
  script: Add script language construct "builtin"

 Makefile.util.def             | 12 ++++++++++
 grub-core/script/execute.c    | 45 ++++++++++++++++++++++-------------
 tests/grub_cmd_builtin.in     | 37 ++++++++++++++++++++++++++++
 tests/grub_script_override.in | 33 +++++++++++++++++++++++++
 4 files changed, 110 insertions(+), 17 deletions(-)
 create mode 100644 tests/grub_cmd_builtin.in
 create mode 100644 tests/grub_script_override.in

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2.27.0