proc/bootconfig: Fix to use correct quotes for value

Fix /proc/bootconfig to select double or single quotes
corrctly according to the value.

If a bootconfig value includes a double quote character,
we must use single-quotes to quote that value.

This modifies if() condition and blocks for avoiding
double-quote in value check in 2 places. Anyway, since
xbc_array_for_each_value() can handle the array which
has a single node correctly.
Thus,

if (vnode && xbc_node_is_array(vnode)) {
xbc_array_for_each_value(vnode) /* vnode->next != NULL */
...
} else {
snprintf(val); /* val is an empty string if !vnode */
}

is equivalent to

if (vnode) {
xbc_array_for_each_value(vnode) /* vnode->next can be NULL */
...
} else {
snprintf(""); /* value is always empty */
}

Link: http://lkml.kernel.org/r/159230244786.65555.3763894451251622488.stgit@devnote2

Cc: [e-mail]
Fixes: c1a3c36017d4 ("proc: bootconfig: Add /proc/bootconfig to show boot config list")
Signed-off-by: Masami Hiramatsu <[e-mail]>
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>

fs/proc/bootconfig.c

···
 static int __init copy_xbc_key_value_list(char *dst, size_t size)
 {
 	struct xbc_node *leaf, *vnode;
-	const char *val;
 	char *key, *end = dst + size;
+	const char *val;
+	char q;
 	int ret = 0;
 
 	key = kzalloc(XBC_KEYLEN_MAX, GFP_KERNEL);
···
 			break;
 		dst += ret;
 		vnode = xbc_node_get_child(leaf);
-		if (vnode && xbc_node_is_array(vnode)) {
+		if (vnode) {
 			xbc_array_for_each_value(vnode, val) {
-				ret = snprintf(dst, rest(dst, end), "\"%s\"%s",
-					val, vnode->next ? ", " : "\n");
+				if (strchr(val, '"'))
+					q = '\'';
+				else
+					q = '"';
+				ret = snprintf(dst, rest(dst, end), "%c%s%c%s",
+					q, val, q, vnode->next ? ", " : "\n");
 				if (ret < 0)
 					goto out;
 				dst += ret;
 			}
 		} else {
-			ret = snprintf(dst, rest(dst, end), "\"%s\"\n", val);
+			ret = snprintf(dst, rest(dst, end), "\"\"\n");
 			if (ret < 0)
 				break;
 			dst += ret;