mount.nfs: parse options - add helper po_contains_prefix

The version options (v3,v4,v4.2) may increase in the future, but they have
a predictable prefix.  Add a parse option helper to locate and return these
options by prefix so that a future increment of version does not require the
addition of strings to a search table.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/utils/mount/parse_opt.c b/utils/mount/parse_opt.c
index 342e210..7ba61c4 100644
--- a/utils/mount/parse_opt.c
+++ b/utils/mount/parse_opt.c
@@ -410,6 +410,30 @@ po_found_t po_contains(struct mount_options *options, char *keyword)
 }
 
 /**
+ * po_contains_prefix - check for presence of an option matching a prefix
+ * @options: pointer to mount options
+ * @prefix: pointer to prefix to match against a keyword
+ * @keyword: pointer to a C string containing the option keyword if found
+ *
+ * On success, *keyword contains the pointer of the matching option's keyword.
+ */
+po_found_t po_contains_prefix(struct mount_options *options,
+								const char *prefix, char **keyword)
+{
+	struct mount_option *option;
+
+	if (options && prefix) {
+		for (option = options->head; option; option = option->next)
+			if (strncmp(option->keyword, prefix, strlen(prefix)) == 0) {
+				*keyword = option->keyword;
+				return PO_FOUND;
+			}
+	}
+
+	return PO_NOT_FOUND;
+}
+
+/**
  * po_get - return the value of the rightmost instance of an option
  * @options: pointer to mount options
  * @keyword: pointer to a C string containing option keyword for which to search