[PATCH 0/2] bootconfig: Add EBNF definition and more tests

[PATCH 0/2] bootconfig: Add EBNF definition and more tests

[Masami Hiramatsu (Google)]

Hi,

Here is a pair of patches to add the EBNF definition and more
parser test cases of bootconfig to formally define the bootconfig
syntax.

---

Masami Hiramatsu (Google) (2):
      Documentation: bootconfig: Add EBNF definiton of bootconfig
      bootconfig: Add more test samples


 Documentation/admin-guide/bootconfig.rst           |   15 +++++++++++++++
 .../samples/bad-array-comment-delimiter.bconf      |    2 ++
 tools/bootconfig/samples/bad-dot-middle.bconf      |    1 +
 .../bootconfig/samples/bad-invalid-operator.bconf  |    1 +
 tools/bootconfig/samples/bad-key-dot-end.bconf     |    1 +
 tools/bootconfig/samples/bad-unclosed-quote.bconf  |    1 +
 .../samples/bad-unexpected-close-brace.bconf       |    4 ++++
 .../samples/exp-good-dot-with-block.bconf          |    1 +
 .../bootconfig/samples/exp-good-empty-block.bconf  |    1 +
 .../samples/exp-good-empty-value-sep.bconf         |    3 +++
 .../samples/exp-good-quoted-newline.bconf          |    2 ++
 tools/bootconfig/samples/good-dot-with-block.bconf |    3 +++
 tools/bootconfig/samples/good-empty-block.bconf    |    1 +
 .../bootconfig/samples/good-empty-value-sep.bconf  |    3 +++
 tools/bootconfig/samples/good-quoted-newline.bconf |    2 ++
 15 files changed, 41 insertions(+)
 create mode 100644 tools/bootconfig/samples/bad-array-comment-delimiter.bconf
 create mode 100644 tools/bootconfig/samples/bad-dot-middle.bconf
 create mode 100644 tools/bootconfig/samples/bad-invalid-operator.bconf
 create mode 100644 tools/bootconfig/samples/bad-key-dot-end.bconf
 create mode 100644 tools/bootconfig/samples/bad-unclosed-quote.bconf
 create mode 100644 tools/bootconfig/samples/bad-unexpected-close-brace.bconf
 create mode 100644 tools/bootconfig/samples/exp-good-dot-with-block.bconf
 create mode 100644 tools/bootconfig/samples/exp-good-empty-block.bconf
 create mode 100644 tools/bootconfig/samples/exp-good-empty-value-sep.bconf
 create mode 100644 tools/bootconfig/samples/exp-good-quoted-newline.bconf
 create mode 100644 tools/bootconfig/samples/good-dot-with-block.bconf
 create mode 100644 tools/bootconfig/samples/good-empty-block.bconf
 create mode 100644 tools/bootconfig/samples/good-empty-value-sep.bconf
 create mode 100644 tools/bootconfig/samples/good-quoted-newline.bconf

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>

[PATCH 1/2] Documentation: bootconfig: Add EBNF definiton of bootconfig

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Add the EBNF definition to Documentation/admin-guide/bootconfig.rst
to formally define the bootconfig syntax.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 Documentation/admin-guide/bootconfig.rst |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index f712758472d5..5c5f736ca982 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -22,6 +22,21 @@ The boot config syntax is a simple structured key-value. Each key consists
 of dot-connected-words, and key and value are connected by ``=``. The value
 string has to be terminated by the following delimiters described below.
 
+The syntax is defined in EBNF as follows::
+
+  Config = { Statement }
+  Statement = [ Key [ Assignment | Block ] | Comment ] ( "\n" | ";" )
+  Assignment = ( "=" | "+=" | ":=" ) ValueList
+  ValueList = [ Value { "," [ { ( Comment | "\n" ) } ] Value } ]
+  Block = "{" { Statement } "}"
+  Key = Word { "." Word }
+  Word = [a-zA-Z0-9_-]+
+  Value = QuotedValue | UnquotedValue
+  QuotedValue = "\"" { any_character_except_double_quote } "\""
+              | "'" { any_character_except_single_quote } "'"
+  UnquotedValue = { any_printable_character_except_delimiters }
+  Comment = "#" { any_character_except_newline }
+
 Each key word must contain only alphabets, numbers, dash (``-``) or underscore
 (``_``). And each value only contains printable characters or spaces except
 for delimiters such as semi-colon (``;``), new-line (``\n``), comma (``,``),

[PATCH 2/2] bootconfig: Add more test samples

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Add more test samples for edge cases (empty block, quoted newline,
various error cases) to tools/bootconfig/samples/.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 .../samples/bad-array-comment-delimiter.bconf      |    2 ++
 tools/bootconfig/samples/bad-dot-middle.bconf      |    1 +
 .../bootconfig/samples/bad-invalid-operator.bconf  |    1 +
 tools/bootconfig/samples/bad-key-dot-end.bconf     |    1 +
 tools/bootconfig/samples/bad-unclosed-quote.bconf  |    1 +
 .../samples/bad-unexpected-close-brace.bconf       |    4 ++++
 .../samples/exp-good-dot-with-block.bconf          |    1 +
 .../bootconfig/samples/exp-good-empty-block.bconf  |    1 +
 .../samples/exp-good-empty-value-sep.bconf         |    3 +++
 .../samples/exp-good-quoted-newline.bconf          |    2 ++
 tools/bootconfig/samples/good-dot-with-block.bconf |    3 +++
 tools/bootconfig/samples/good-empty-block.bconf    |    1 +
 .../bootconfig/samples/good-empty-value-sep.bconf  |    3 +++
 tools/bootconfig/samples/good-quoted-newline.bconf |    2 ++
 14 files changed, 26 insertions(+)
 create mode 100644 tools/bootconfig/samples/bad-array-comment-delimiter.bconf
 create mode 100644 tools/bootconfig/samples/bad-dot-middle.bconf
 create mode 100644 tools/bootconfig/samples/bad-invalid-operator.bconf
 create mode 100644 tools/bootconfig/samples/bad-key-dot-end.bconf
 create mode 100644 tools/bootconfig/samples/bad-unclosed-quote.bconf
 create mode 100644 tools/bootconfig/samples/bad-unexpected-close-brace.bconf
 create mode 100644 tools/bootconfig/samples/exp-good-dot-with-block.bconf
 create mode 100644 tools/bootconfig/samples/exp-good-empty-block.bconf
 create mode 100644 tools/bootconfig/samples/exp-good-empty-value-sep.bconf
 create mode 100644 tools/bootconfig/samples/exp-good-quoted-newline.bconf
 create mode 100644 tools/bootconfig/samples/good-dot-with-block.bconf
 create mode 100644 tools/bootconfig/samples/good-empty-block.bconf
 create mode 100644 tools/bootconfig/samples/good-empty-value-sep.bconf
 create mode 100644 tools/bootconfig/samples/good-quoted-newline.bconf

diff --git a/tools/bootconfig/samples/bad-array-comment-delimiter.bconf b/tools/bootconfig/samples/bad-array-comment-delimiter.bconf
new file mode 100644
index 000000000000..5300cef82aa3
--- /dev/null
+++ b/tools/bootconfig/samples/bad-array-comment-delimiter.bconf
@@ -0,0 +1,2 @@
+key = 1 # comment
+      , 2 # Error: comment between value and its comma delimiter
diff --git a/tools/bootconfig/samples/bad-dot-middle.bconf b/tools/bootconfig/samples/bad-dot-middle.bconf
new file mode 100644
index 000000000000..b3bd19e3c991
--- /dev/null
+++ b/tools/bootconfig/samples/bad-dot-middle.bconf
@@ -0,0 +1 @@
+key..word = value # Double dots are not allowed
diff --git a/tools/bootconfig/samples/bad-invalid-operator.bconf b/tools/bootconfig/samples/bad-invalid-operator.bconf
new file mode 100644
index 000000000000..ca19895bee8a
--- /dev/null
+++ b/tools/bootconfig/samples/bad-invalid-operator.bconf
@@ -0,0 +1 @@
+key ?= value # Unsupported operator
diff --git a/tools/bootconfig/samples/bad-key-dot-end.bconf b/tools/bootconfig/samples/bad-key-dot-end.bconf
new file mode 100644
index 000000000000..57ae39d36e95
--- /dev/null
+++ b/tools/bootconfig/samples/bad-key-dot-end.bconf
@@ -0,0 +1 @@
+key. = value # Key cannot end with a dot
diff --git a/tools/bootconfig/samples/bad-unclosed-quote.bconf b/tools/bootconfig/samples/bad-unclosed-quote.bconf
new file mode 100644
index 000000000000..9384e68d17f6
--- /dev/null
+++ b/tools/bootconfig/samples/bad-unclosed-quote.bconf
@@ -0,0 +1 @@
+key = "unclosed quote
diff --git a/tools/bootconfig/samples/bad-unexpected-close-brace.bconf b/tools/bootconfig/samples/bad-unexpected-close-brace.bconf
new file mode 100644
index 000000000000..a372be395200
--- /dev/null
+++ b/tools/bootconfig/samples/bad-unexpected-close-brace.bconf
@@ -0,0 +1,4 @@
+key {
+    subkey = value
+}
+} # Extra closing brace
diff --git a/tools/bootconfig/samples/exp-good-dot-with-block.bconf b/tools/bootconfig/samples/exp-good-dot-with-block.bconf
new file mode 100644
index 000000000000..ff563ceec024
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-dot-with-block.bconf
@@ -0,0 +1 @@
+key.subkey.subsubkey = "value";
diff --git a/tools/bootconfig/samples/exp-good-empty-block.bconf b/tools/bootconfig/samples/exp-good-empty-block.bconf
new file mode 100644
index 000000000000..fe460e8e675c
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-empty-block.bconf
@@ -0,0 +1 @@
+key;
diff --git a/tools/bootconfig/samples/exp-good-empty-value-sep.bconf b/tools/bootconfig/samples/exp-good-empty-value-sep.bconf
new file mode 100644
index 000000000000..266851aae8f2
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-empty-value-sep.bconf
@@ -0,0 +1,3 @@
+key1 = "";
+key2 = "";
+key3 = "";
diff --git a/tools/bootconfig/samples/exp-good-quoted-newline.bconf b/tools/bootconfig/samples/exp-good-quoted-newline.bconf
new file mode 100644
index 000000000000..2b5166541df6
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-quoted-newline.bconf
@@ -0,0 +1,2 @@
+key = "value
+that spans multiple lines";
diff --git a/tools/bootconfig/samples/good-dot-with-block.bconf b/tools/bootconfig/samples/good-dot-with-block.bconf
new file mode 100644
index 000000000000..3d9bef7daa2f
--- /dev/null
+++ b/tools/bootconfig/samples/good-dot-with-block.bconf
@@ -0,0 +1,3 @@
+key.subkey {
+    subsubkey = value
+} # Combination of dot-notation and block syntax
diff --git a/tools/bootconfig/samples/good-empty-block.bconf b/tools/bootconfig/samples/good-empty-block.bconf
new file mode 100644
index 000000000000..8c390f37b177
--- /dev/null
+++ b/tools/bootconfig/samples/good-empty-block.bconf
@@ -0,0 +1 @@
+key { } # Empty block should be allowed and ignored
diff --git a/tools/bootconfig/samples/good-empty-value-sep.bconf b/tools/bootconfig/samples/good-empty-value-sep.bconf
new file mode 100644
index 000000000000..fbfb9a17ff99
--- /dev/null
+++ b/tools/bootconfig/samples/good-empty-value-sep.bconf
@@ -0,0 +1,3 @@
+key1 = ;
+key2 = 
+key3 = # comment
diff --git a/tools/bootconfig/samples/good-quoted-newline.bconf b/tools/bootconfig/samples/good-quoted-newline.bconf
new file mode 100644
index 000000000000..8c9cd088579a
--- /dev/null
+++ b/tools/bootconfig/samples/good-quoted-newline.bconf
@@ -0,0 +1,2 @@
+key = "value
+that spans multiple lines" # Quoted values can contain newlines

Re: [PATCH 1/2] Documentation: bootconfig: Add EBNF definiton of bootconfig

[Masami Hiramatsu]

On Sat, 14 Mar 2026 18:06:40 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Add the EBNF definition to Documentation/admin-guide/bootconfig.rst
> to formally define the bootconfig syntax.
> 

Wait, I rethink it may be better to be a separated section
so that it can be referred easily.
Let me update it.

Thanks,

> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
>  Documentation/admin-guide/bootconfig.rst |   15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
> index f712758472d5..5c5f736ca982 100644
> --- a/Documentation/admin-guide/bootconfig.rst
> +++ b/Documentation/admin-guide/bootconfig.rst
> @@ -22,6 +22,21 @@ The boot config syntax is a simple structured key-value. Each key consists
>  of dot-connected-words, and key and value are connected by ``=``. The value
>  string has to be terminated by the following delimiters described below.
>  
> +The syntax is defined in EBNF as follows::
> +
> +  Config = { Statement }
> +  Statement = [ Key [ Assignment | Block ] | Comment ] ( "\n" | ";" )
> +  Assignment = ( "=" | "+=" | ":=" ) ValueList
> +  ValueList = [ Value { "," [ { ( Comment | "\n" ) } ] Value } ]
> +  Block = "{" { Statement } "}"
> +  Key = Word { "." Word }
> +  Word = [a-zA-Z0-9_-]+
> +  Value = QuotedValue | UnquotedValue
> +  QuotedValue = "\"" { any_character_except_double_quote } "\""
> +              | "'" { any_character_except_single_quote } "'"
> +  UnquotedValue = { any_printable_character_except_delimiters }
> +  Comment = "#" { any_character_except_newline }
> +
>  Each key word must contain only alphabets, numbers, dash (``-``) or underscore
>  (``_``). And each value only contains printable characters or spaces except
>  for delimiters such as semi-colon (``;``), new-line (``\n``), comma (``,``),
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>