From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Terminate the value search for a key if it hits a newline and make
the value empty.
When we pass a bootconfig with an empty value terminated by the
newline, like below::
foo =
bar = value
Current bootconfig interprets it as a single entry::
foo = "bar = value";
The Documentation/admin-guide/bootconfig.rst defines the value
itself is terminated by newline:
The value has to be terminated by semi-colon (``;``) or newline (``\n``).
but it does not define when the value search is terminated.
This changes the behavior to more line-oriented, so that it can
clear how it is working.
- The value search of key-value pair will be terminated by a comment
or newline.
- The value search of an array will continue beyond comments and
newlines.
Thus, with this update, the above example is interpreted as::
foo = "";
bar = "value";
And the below example will cause a syntax error because "bar" is expected
as a key but it has ','.
foo =
bar, buz
According to this change, one wrong example config is updated.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
- Fix to handle multi-line array case correctly.
- Make this as a spec update, not fix.
---
.../samples/good-array-space-comment.bconf | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index 7a86042c9b6d..843b24b8de88 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -20,18 +20,26 @@ Config File Syntax
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
-has to be terminated by semi-colon (``;``) or newline (``\n``).
-For array value, array entries are separated by comma (``,``). ::
-
- KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
-
-Unlike the kernel command line syntax, spaces are OK around the comma and ``=``.
+string has to be terminated by the following delimiters described below.
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 (``,``),
hash (``#``) and closing brace (``}``).
+If the ``=`` is followed by whitespace up to one of these delimiters, the
+key is assigned an empty value.
+
+For arrays, the array values are comma (``,``) separated, and comments and
+line breaks with newline (``\n``) are allowed between array values for
+readability. Thus the first entry of the array must be the same line of the
+key.::
+
+ KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
+
+Unlike the kernel command line syntax, white spaces (including tabs) are
+ignored around the comma and ``=``.
+
If you want to use those delimiters in a value, you can use either double-
quotes (``"VALUE"``) or single-quotes (``'VALUE'``) to quote it. Note that
you can not escape these quotes.
@@ -138,8 +146,8 @@ This is parsed as below::
foo = value
bar = 1, 2, 3
-Note that you can not put a comment between value and delimiter(``,`` or
-``;``). This means following config has a syntax error ::
+Note that you can NOT put a comment or a newline between value and delimiter
+(``,`` or ``;``). This means following config has a syntax error ::
key = 1 # comment
,2
diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index 81f29c29f47b..c210fb8b1e85 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -557,17 +557,13 @@ static int __init __xbc_close_brace(char *p)
/*
* Return delimiter or error, no node added. As same as lib/cmdline.c,
* you can use " around spaces, but can't escape " for value.
+ * *@__v must point real value string. (not including spaces before value.)
*/
static int __init __xbc_parse_value(char **__v, char **__n)
{
char *p, *v = *__v;
int c, quotes = 0;
- v = skip_spaces(v);
- while (*v == '#') {
- v = skip_comment(v);
- v = skip_spaces(v);
- }
if (*v == '"' || *v == '\'') {
quotes = *v;
v++;
@@ -617,6 +613,13 @@ static int __init xbc_parse_array(char **__v)
last_parent = xbc_node_get_child(last_parent);
do {
+ /* Search the next array value beyond comments and empty lines */
+ next = skip_spaces(*__v);
+ while (*next == '#') {
+ next = skip_comment(next);
+ next = skip_spaces(next);
+ }
+ *__v = next;
c = __xbc_parse_value(__v, &next);
if (c < 0)
return c;
@@ -701,9 +704,17 @@ static int __init xbc_parse_kv(char **k, char *v, int op)
if (ret)
return ret;
- c = __xbc_parse_value(&v, &next);
- if (c < 0)
- return c;
+ v = skip_spaces_until_newline(v);
+ /* If there is a comment, this has an mpty value. */
+ if (*v == '#') {
+ next = skip_comment(v);
+ *v = '\0';
+ c = '\n';
+ } else {
+ c = __xbc_parse_value(&v, &next);
+ if (c < 0)
+ return c;
+ }
child = xbc_node_get_child(last_parent);
if (child && xbc_node_is_value(child)) {
diff --git a/tools/bootconfig/samples/good-array-space-comment.bconf b/tools/bootconfig/samples/good-array-space-comment.bconf
index 45b938dc0695..416fa2ed4109 100644
--- a/tools/bootconfig/samples/good-array-space-comment.bconf
+++ b/tools/bootconfig/samples/good-array-space-comment.bconf
@@ -1,4 +1,3 @@
-key = # comment
- "value1", # comment1
+key = "value1", # comment1
"value2" , # comment2
"value3"On Wed, 4 Feb 2026 17:33:48 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Terminate the value search for a key if it hits a newline and make
> the value empty.
>
> When we pass a bootconfig with an empty value terminated by the
> newline, like below::
>
> foo =
> bar = value
>
> Current bootconfig interprets it as a single entry::
>
> foo = "bar = value";
>
> The Documentation/admin-guide/bootconfig.rst defines the value
> itself is terminated by newline:
>
> The value has to be terminated by semi-colon (``;``) or newline (``\n``).
>
> but it does not define when the value search is terminated.
> This changes the behavior to more line-oriented, so that it can
to be more line-oriented
> clear how it is working.
so that it is clearer in how it works.
>
> - The value search of key-value pair will be terminated by a comment
> or newline.
> - The value search of an array will continue beyond comments and
> newlines.
>
> Thus, with this update, the above example is interpreted as::
>
> foo = "";
> bar = "value";
>
> And the below example will cause a syntax error because "bar" is expected
> as a key but it has ','.
>
> foo =
> bar, buz
>
> According to this change, one wrong example config is updated.
>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
> Changes in v2:
> - Fix to handle multi-line array case correctly.
> - Make this as a spec update, not fix.
> ---
> .../samples/good-array-space-comment.bconf | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
> index 7a86042c9b6d..843b24b8de88 100644
> --- a/Documentation/admin-guide/bootconfig.rst
> +++ b/Documentation/admin-guide/bootconfig.rst
> @@ -20,18 +20,26 @@ Config File Syntax
>
> 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
> -has to be terminated by semi-colon (``;``) or newline (``\n``).
> -For array value, array entries are separated by comma (``,``). ::
> -
> - KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
> -
> -Unlike the kernel command line syntax, spaces are OK around the comma and ``=``.
> +string has to be terminated by the following delimiters described below.
>
> 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 (``,``),
> hash (``#``) and closing brace (``}``).
>
> +If the ``=`` is followed by whitespace up to one of these delimiters, the
> +key is assigned an empty value.
> +
> +For arrays, the array values are comma (``,``) separated, and comments and
> +line breaks with newline (``\n``) are allowed between array values for
> +readability. Thus the first entry of the array must be the same line of the
must be on the same line as the key.
> +key.::
> +
> + KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
> +
> +Unlike the kernel command line syntax, white spaces (including tabs) are
> +ignored around the comma and ``=``.
> +
> If you want to use those delimiters in a value, you can use either double-
> quotes (``"VALUE"``) or single-quotes (``'VALUE'``) to quote it. Note that
> you can not escape these quotes.
> @@ -138,8 +146,8 @@ This is parsed as below::
> foo = value
> bar = 1, 2, 3
>
> -Note that you can not put a comment between value and delimiter(``,`` or
> -``;``). This means following config has a syntax error ::
> +Note that you can NOT put a comment or a newline between value and delimiter
> +(``,`` or ``;``). This means following config has a syntax error ::
>
> key = 1 # comment
> ,2
> diff --git a/lib/bootconfig.c b/lib/bootconfig.c
> index 81f29c29f47b..c210fb8b1e85 100644
> --- a/lib/bootconfig.c
> +++ b/lib/bootconfig.c
> @@ -557,17 +557,13 @@ static int __init __xbc_close_brace(char *p)
> /*
> * Return delimiter or error, no node added. As same as lib/cmdline.c,
> * you can use " around spaces, but can't escape " for value.
> + * *@__v must point real value string. (not including spaces before value.)
> */
> static int __init __xbc_parse_value(char **__v, char **__n)
> {
> char *p, *v = *__v;
> int c, quotes = 0;
>
> - v = skip_spaces(v);
> - while (*v == '#') {
> - v = skip_comment(v);
> - v = skip_spaces(v);
> - }
> if (*v == '"' || *v == '\'') {
> quotes = *v;
> v++;
> @@ -617,6 +613,13 @@ static int __init xbc_parse_array(char **__v)
> last_parent = xbc_node_get_child(last_parent);
>
> do {
> + /* Search the next array value beyond comments and empty lines */
> + next = skip_spaces(*__v);
> + while (*next == '#') {
> + next = skip_comment(next);
> + next = skip_spaces(next);
> + }
> + *__v = next;
> c = __xbc_parse_value(__v, &next);
> if (c < 0)
> return c;
> @@ -701,9 +704,17 @@ static int __init xbc_parse_kv(char **k, char *v, int op)
> if (ret)
> return ret;
>
> - c = __xbc_parse_value(&v, &next);
> - if (c < 0)
> - return c;
> + v = skip_spaces_until_newline(v);
> + /* If there is a comment, this has an mpty value. */
empty value
-- Steve
> + if (*v == '#') {
> + next = skip_comment(v);
> + *v = '\0';
> + c = '\n';
> + } else {
> + c = __xbc_parse_value(&v, &next);
> + if (c < 0)
> + return c;
> + }
>
> child = xbc_node_get_child(last_parent);
> if (child && xbc_node_is_value(child)) {
> diff --git a/tools/bootconfig/samples/good-array-space-comment.bconf b/tools/bootconfig/samples/good-array-space-comment.bconf
> index 45b938dc0695..416fa2ed4109 100644
> --- a/tools/bootconfig/samples/good-array-space-comment.bconf
> +++ b/tools/bootconfig/samples/good-array-space-comment.bconf
> @@ -1,4 +1,3 @@
> -key = # comment
> - "value1", # comment1
> +key = "value1", # comment1
> "value2" , # comment2
> "value3"
On Wed, 4 Feb 2026 17:20:57 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed, 4 Feb 2026 17:33:48 +0900
> "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
>
> > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> >
> > Terminate the value search for a key if it hits a newline and make
> > the value empty.
> >
> > When we pass a bootconfig with an empty value terminated by the
> > newline, like below::
> >
> > foo =
> > bar = value
> >
> > Current bootconfig interprets it as a single entry::
> >
> > foo = "bar = value";
> >
> > The Documentation/admin-guide/bootconfig.rst defines the value
> > itself is terminated by newline:
> >
> > The value has to be terminated by semi-colon (``;``) or newline (``\n``).
> >
> > but it does not define when the value search is terminated.
> > This changes the behavior to more line-oriented, so that it can
>
> to be more line-oriented
>
> > clear how it is working.
>
> so that it is clearer in how it works.
>
OK,
>
> >
> > - The value search of key-value pair will be terminated by a comment
> > or newline.
> > - The value search of an array will continue beyond comments and
> > newlines.
> >
> > Thus, with this update, the above example is interpreted as::
> >
> > foo = "";
> > bar = "value";
> >
> > And the below example will cause a syntax error because "bar" is expected
> > as a key but it has ','.
> >
> > foo =
> > bar, buz
> >
> > According to this change, one wrong example config is updated.
> >
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > ---
> > Changes in v2:
> > - Fix to handle multi-line array case correctly.
> > - Make this as a spec update, not fix.
> > ---
> > .../samples/good-array-space-comment.bconf | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
> > index 7a86042c9b6d..843b24b8de88 100644
> > --- a/Documentation/admin-guide/bootconfig.rst
> > +++ b/Documentation/admin-guide/bootconfig.rst
> > @@ -20,18 +20,26 @@ Config File Syntax
> >
> > 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
> > -has to be terminated by semi-colon (``;``) or newline (``\n``).
> > -For array value, array entries are separated by comma (``,``). ::
> > -
> > - KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
> > -
> > -Unlike the kernel command line syntax, spaces are OK around the comma and ``=``.
> > +string has to be terminated by the following delimiters described below.
> >
> > 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 (``,``),
> > hash (``#``) and closing brace (``}``).
> >
> > +If the ``=`` is followed by whitespace up to one of these delimiters, the
> > +key is assigned an empty value.
> > +
> > +For arrays, the array values are comma (``,``) separated, and comments and
> > +line breaks with newline (``\n``) are allowed between array values for
> > +readability. Thus the first entry of the array must be the same line of the
>
> must be on the same line as the key.
OK.
>
> > +key.::
> > +
> > + KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
> > +
> > +Unlike the kernel command line syntax, white spaces (including tabs) are
> > +ignored around the comma and ``=``.
> > +
> > If you want to use those delimiters in a value, you can use either double-
> > quotes (``"VALUE"``) or single-quotes (``'VALUE'``) to quote it. Note that
> > you can not escape these quotes.
> > @@ -138,8 +146,8 @@ This is parsed as below::
> > foo = value
> > bar = 1, 2, 3
> >
> > -Note that you can not put a comment between value and delimiter(``,`` or
> > -``;``). This means following config has a syntax error ::
> > +Note that you can NOT put a comment or a newline between value and delimiter
> > +(``,`` or ``;``). This means following config has a syntax error ::
> >
> > key = 1 # comment
> > ,2
> > diff --git a/lib/bootconfig.c b/lib/bootconfig.c
> > index 81f29c29f47b..c210fb8b1e85 100644
> > --- a/lib/bootconfig.c
> > +++ b/lib/bootconfig.c
> > @@ -557,17 +557,13 @@ static int __init __xbc_close_brace(char *p)
> > /*
> > * Return delimiter or error, no node added. As same as lib/cmdline.c,
> > * you can use " around spaces, but can't escape " for value.
> > + * *@__v must point real value string. (not including spaces before value.)
> > */
> > static int __init __xbc_parse_value(char **__v, char **__n)
> > {
> > char *p, *v = *__v;
> > int c, quotes = 0;
> >
> > - v = skip_spaces(v);
> > - while (*v == '#') {
> > - v = skip_comment(v);
> > - v = skip_spaces(v);
> > - }
> > if (*v == '"' || *v == '\'') {
> > quotes = *v;
> > v++;
> > @@ -617,6 +613,13 @@ static int __init xbc_parse_array(char **__v)
> > last_parent = xbc_node_get_child(last_parent);
> >
> > do {
> > + /* Search the next array value beyond comments and empty lines */
> > + next = skip_spaces(*__v);
> > + while (*next == '#') {
> > + next = skip_comment(next);
> > + next = skip_spaces(next);
> > + }
> > + *__v = next;
> > c = __xbc_parse_value(__v, &next);
> > if (c < 0)
> > return c;
> > @@ -701,9 +704,17 @@ static int __init xbc_parse_kv(char **k, char *v, int op)
> > if (ret)
> > return ret;
> >
> > - c = __xbc_parse_value(&v, &next);
> > - if (c < 0)
> > - return c;
> > + v = skip_spaces_until_newline(v);
> > + /* If there is a comment, this has an mpty value. */
>
> empty value
Thanks!
>
> -- Steve
>
> > + if (*v == '#') {
> > + next = skip_comment(v);
> > + *v = '\0';
> > + c = '\n';
> > + } else {
> > + c = __xbc_parse_value(&v, &next);
> > + if (c < 0)
> > + return c;
> > + }
> >
> > child = xbc_node_get_child(last_parent);
> > if (child && xbc_node_is_value(child)) {
> > diff --git a/tools/bootconfig/samples/good-array-space-comment.bconf b/tools/bootconfig/samples/good-array-space-comment.bconf
> > index 45b938dc0695..416fa2ed4109 100644
> > --- a/tools/bootconfig/samples/good-array-space-comment.bconf
> > +++ b/tools/bootconfig/samples/good-array-space-comment.bconf
> > @@ -1,4 +1,3 @@
> > -key = # comment
> > - "value1", # comment1
> > +key = "value1", # comment1
> > "value2" , # comment2
> > "value3"
>
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
© 2016 - 2026 Red Hat, Inc.