linux-kernel - [PATCH 0/3] bootconfig: Add value override operator

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Date:   Thu, 16 Jul 2020 01:00:21 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Alistair Delva <adelva@...gle.com>, mhiramat@...nel.org,
        linux-doc@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/3] bootconfig: Add value override operator

Hi,

Here is a seires of value-override operator support for bootconfig.

Currently, the bootconfig syntax supports normal assignment operator
("=") and value append operator ("+="), but there is no way to
override (or update) existing value.

This patch adds the value override operator (":=") to update the
existing value with another value. For example,

key.word = value1
key.word := value2, value3

In this case, the 2nd "key.word" config overwrites the 1st one.
Thus this is equal to;

key.word = value2, value3

Note that it is still not allowed to override a subkey with
a value, and a value with a subkey. This means the following
case is not allowed.

key.word = value1
key := value2 # Error!

With this change, if the bootloader wants to change some value
in the default bootconfig, it doesn't need to parse the existing
bootconfig, but it can just append the new configs at the tail
of the bootconfig and update the footer (size, checksum and magic
word).

Thank you,

---

Masami Hiramatsu (3):
      lib/bootconfig: Add override operator support
      tools/bootconfig: Add testcases for value override operator
      Documentation: bootconfig: Add bootconfig override operator

 Documentation/admin-guide/bootconfig.rst     |   11 +++++++++
 lib/bootconfig.c                             |   33 ++++++++++++++++++--------
 tools/bootconfig/samples/bad-override.bconf  |    3 ++
 tools/bootconfig/samples/bad-override2.bconf |    3 ++
 tools/bootconfig/samples/good-override.bconf |    6 +++++
 tools/bootconfig/test-bootconfig.sh          |   13 ++++++++++
 6 files changed, 59 insertions(+), 10 deletions(-)
 create mode 100644 tools/bootconfig/samples/bad-override.bconf
 create mode 100644 tools/bootconfig/samples/bad-override2.bconf
 create mode 100644 tools/bootconfig/samples/good-override.bconf

--
Masami Hiramatsu (Linaro) <mhiramat@...nel.org>