[for-linus][PATCH 14/15] bootconfig: Prohibit re-defining value on same key

From: Steven Rostedt
Date: Mon Feb 24 2020 - 12:22:47 EST


From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

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

This rejects the following value re-definition.

key = value1
...
key = value2

You should rewrite value1 to value2 in this case.

Link: http://lkml.kernel.org/r/158227282199.12842.10110929876059658601.stgit@devnote2

Suggested-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
[ Fixed spelling of arraies to arrays ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
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..57119fb69d36 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 arrays 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
--
2.25.0