[PATCH 9/9] nfs: parse nfsport and mount port from file system options

[Uwe Kleine-König]

This allows to use unfs3 on the server side which doesn't integrate into
portmap/rpcbind which results in the port not being impossible to lookup
via rpc calls to the portmap program.

Use it like:

	mount -t nfs -o port=2703,mountport=2703 192.168.77.157:/root /mnt/nfs

Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
 fs/nfs.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 51 insertions(+), 11 deletions(-)

diff --git a/fs/nfs.c b/fs/nfs.c
index 8eec63078dd3..50b3744b4551 100644
--- a/fs/nfs.c
+++ b/fs/nfs.c
@@ -1305,6 +1305,38 @@ static int nfs_stat(struct device_d *dev, const char *filename, struct stat *s)
 	}
 }
 
+static void parseopt_hu(const char *options, const char *opt,
+		unsigned short *val)
+{
+	const char *start;
+	size_t optlen = strlen(opt);
+	ulong v;
+	char *endp;
+
+again:
+	start = strstr(options, opt);
+
+	if (!start)
+		return;
+
+	if (start > options && start[-1] != ',') {
+		options = start;
+		goto again;
+	}
+
+	if (start[optlen] != '=') {
+		options = start;
+		goto again;
+	}
+
+	v = simple_strtoul(start + optlen + 1, &endp, 0);
+	if (v > USHORT_MAX)
+		return;
+
+	if (*endp == ',' || *endp == '\0')
+		*val = v;
+}
+
 static int nfs_probe(struct device_d *dev)
 {
 	struct fs_device_d *fsdev = dev_to_fs_device(dev);
@@ -1340,19 +1372,27 @@ static int nfs_probe(struct device_d *dev)
 	/* Need a priviliged source port */
 	net_udp_bind(npriv->con, 1000);
 
-	ret = rpc_lookup_req(npriv, PROG_MOUNT, 1);
-	if (ret < 0) {
-		printf("lookup mount port failed with %d\n", ret);
-		goto err2;
+	parseopt_hu(fsdev->options, "mountport", &npriv->mount_port);
+	if (!npriv->mount_port) {
+		ret = rpc_lookup_req(npriv, PROG_MOUNT, 1);
+		if (ret < 0) {
+			printf("lookup mount port failed with %d\n", ret);
+			goto err2;
+		}
+		npriv->mount_port = ret;
 	}
-	npriv->mount_port = ret;
-
-	ret = rpc_lookup_req(npriv, PROG_NFS, 3);
-	if (ret < 0) {
-		printf("lookup nfs port failed with %d\n", ret);
-		goto err2;
+	debug("mount port: %hu\n", npriv->mount_port);
+
+	parseopt_hu(fsdev->options, "port", &npriv->nfs_port);
+	if (!npriv->nfs_port) {
+		ret = rpc_lookup_req(npriv, PROG_NFS, 3);
+		if (ret < 0) {
+			printf("lookup nfs port failed with %d\n", ret);
+			goto err2;
+		}
+		npriv->nfs_port = ret;
 	}
-	npriv->nfs_port = ret;
+	debug("nfs port: %d\n", npriv->nfs_port);
 
 	ret = nfs_mount_req(npriv);
 	if (ret) {
-- 
1.8.5.2