Add a free_iovec() function to reset iovec's.

The primary purpose is to call nmount() in a loop with new iovec's so
free_iovec takes arguments by reference and resets their values.

Reviewed by:	cem
MFC after:	1 week
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D8513

2 files changed, 15 insertions, 0 deletions

diff --git a/sbin/mount/getmntopts.c b/sbin/mount/getmntopts.c
index f8a34530c5dc..59a383ebe5f0 100644
--- a/sbin/mount/getmntopts.c
+++ b/sbin/mount/getmntopts.c
@@ -181,3 +181,17 @@ build_iovec_argf(struct iovec **iov, int *iovlen, const char *name,
 	va_end(ap);
 	build_iovec(iov, iovlen, name, strdup(val), (size_t)-1);
 }
+
+/*
+ * Free the iovec and reset to NULL with zero length.  Useful for calling
+ * nmount in a loop.
+ */
+void
+free_iovec(struct iovec **iov, int *iovlen)
+{
+	int i;
+
+	for (i = 0; i < *iovlen; i++)
+		free((*iov)[i].iov_base);
+	free(*iov);
+}
diff --git a/sbin/mount/mntopts.h b/sbin/mount/mntopts.h
index d273dde9f1d5..4cb83f15e6e5 100644
--- a/sbin/mount/mntopts.h
+++ b/sbin/mount/mntopts.h
@@ -99,3 +99,4 @@ int checkpath(const char *, char resolved_path[]);
 extern int getmnt_silent;
 void build_iovec(struct iovec **iov, int *iovlen, const char *name, void *val, size_t len);
 void build_iovec_argf(struct iovec **iov, int *iovlen, const char *name, const char *fmt, ...);
+void free_iovec(struct iovec **iovec, int *iovlen);