bootconfig: Prohibit re-defining value on same key

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@goodmis.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
[ Fixed spelling of arraies to arrays ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index dfeffa7..57119fb 100644 (file)
--- 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 54ac623..2ef304d 100644 (file)
--- 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 (file)
index 0000000..e8d983a
--- /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