[PATCH v3 1/2] bootconfig: Prohibit re-defining value on same key

Masami Hiramatsu
2020-02-21T08:31:43Z

Currently, bootconfig adds new value on the existing key
to the tail of an array. But this looks a bit confusing
because admin can rewrite original value in same config
file easily.

This rejects following value re-definition.

key = value1
...
key = value2

You should rewrite value1 to value2 in this case.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Documentation/admin-guide/bootconfig.rst | 11 ++++++++++-
lib/bootconfig.c | 13 ++++++++-----
tools/bootconfig/samples/bad-samekey.bconf | 6 ++++++
3 files changed, 24 insertions(+), 6 deletions(-)
create mode 100644 tools/bootconfig/samples/bad-samekey.bconf

diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index dfeffa73dca3..9ee7650b7817 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -62,7 +62,16 @@ Or more shorter, written as following::
In both styles, same key words are automatically merged when parsing it
at boot time. So you can append similar trees or key-values.

-Note that a sub-key and a value can not co-exist under a parent key.
+Same-key Values
+---------------
+
+It is prohibited that two or more values or arraies share a same-key.
+For example,::
+
+ foo = bar, baz
+ foo = qux # !ERROR! we can not re-define same key
+
+Also, a sub-key and a value can not co-exist under a parent key.
For example, following config is NOT allowed.::

foo = value1
diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index 54ac623ca781..2ef304db31f2 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -581,7 +581,7 @@ static int __init __xbc_parse_keys(char *k)
static int __init xbc_parse_kv(char **k, char *v)
{
struct xbc_node *prev_parent = last_parent;
- struct xbc_node *node, *child;
+ struct xbc_node *child;
char *next;
int c, ret;

@@ -590,15 +590,18 @@ static int __init xbc_parse_kv(char **k, char *v)
return ret;

child = xbc_node_get_child(last_parent);
- if (child && xbc_node_is_key(child))
- return xbc_parse_error("Value is mixed with subkey", v);
+ if (child) {
+ if (xbc_node_is_key(child))
+ return xbc_parse_error("Value is mixed with subkey", v);
+ else
+ return xbc_parse_error("Value is redefined", v);
+ }

c = __xbc_parse_value(&v, &next);
if (c < 0)
return c;

- node = xbc_add_sibling(v, XBC_VALUE);
- if (!node)
+ if (!xbc_add_sibling(v, XBC_VALUE))
return -ENOMEM;

if (c == ',') { /* Array */
diff --git a/tools/bootconfig/samples/bad-samekey.bconf b/tools/bootconfig/samples/bad-samekey.bconf
new file mode 100644
index 000000000000..e8d983a4563c
--- /dev/null
+++ b/tools/bootconfig/samples/bad-samekey.bconf
@@ -0,0 +1,6 @@
+# Same key value is not allowed
+key {
+ foo = value
+ bar = value2
+}
+key.foo = value