Move list_cloners to libifconfig

Move list_cloners() from ifconfig(8) to libifconfig(3) where it can be
reused by other consumers.

Reviewed by:	kp
Differential Revision:	https://reviews.freebsd.org/D26858

2 files changed, 42 insertions, 0 deletions

diff --git a/lib/libifconfig/libifconfig.c b/lib/libifconfig/libifconfig.c
index 4d6e702db9dec..e67c4e4de04e7 100644
--- a/lib/libifconfig/libifconfig.c
+++ b/lib/libifconfig/libifconfig.c
@@ -628,3 +628,35 @@ ifconfig_set_vlantag(ifconfig_handle_t *h, const char *name,
 	}
 	return (0);
 }
+
+int
+ifconfig_list_cloners(ifconfig_handle_t *h, char **bufp, size_t *lenp)
+{
+	struct if_clonereq ifcr;
+	char *buf;
+
+	memset(&ifcr, 0, sizeof(ifcr));
+	*bufp = NULL;
+	*lenp = 0;
+
+	if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCIFGCLONERS, &ifcr) < 0)
+		return (-1);
+
+	buf = malloc(ifcr.ifcr_total * IFNAMSIZ);
+	if (buf == NULL) {
+		h->error.errtype = OTHER;
+		h->error.errcode = ENOMEM;
+		return (-1);
+	}
+
+	ifcr.ifcr_count = ifcr.ifcr_total;
+	ifcr.ifcr_buffer = buf;
+	if (ifconfig_ioctlwrap(h, AF_LOCAL, SIOCIFGCLONERS, &ifcr) < 0) {
+		free(buf);
+		return (-1);
+	}
+
+	*bufp = buf;
+	*lenp = ifcr.ifcr_total;
+	return (0);
+}
diff --git a/lib/libifconfig/libifconfig.h b/lib/libifconfig/libifconfig.h
index ca8e8e817dc1f..46a13ae27d69b 100644
--- a/lib/libifconfig/libifconfig.h
+++ b/lib/libifconfig/libifconfig.h
@@ -279,3 +279,13 @@ int ifconfig_create_interface_vlan(ifconfig_handle_t *h, const char *name,
 
 int ifconfig_set_vlantag(ifconfig_handle_t *h, const char *name,
     const char *vlandev, const unsigned short vlantag);
+
+/** Gets the names of all interface cloners available on the system
+ * @param bufp	Set to the address of the names buffer on success or NULL
+ *              if an error occurs.  This buffer must be freed when done.
+ * @param lenp	Set to the number of names in the returned buffer or 0
+ * 		if an error occurs.  Each name is contained within an
+ * 		IFNAMSIZ length slice of the buffer, for a total buffer
+ * 		length of *lenp * IFNAMSIZ bytes.
+ */
+int ifconfig_list_cloners(ifconfig_handle_t *h, char **bufp, size_t *lenp);