Add boot.nfsroot.options loader tunable.

It allows to specify options for NFS root file system.
Currently supported options are: soft, intr, conn, lockd.

I'm adding this functionality mostly for 'lockd' option, which is only
honored when performing the initial mount and will be silently ignored
if used while updating the mount options.

This will allow to use flock(2) without the need of using varmfs or
rpc.lockd and friends.

Example of use:
boot.nfsroot.options="intr,lockd"

MFC after:	2 weeks

1 files changed, 30 insertions, 0 deletions

diff --git a/sys/nfsclient/nfs_diskless.c b/sys/nfsclient/nfs_diskless.c
index 9f17cd9330a9..56a5a2faab9c 100644
--- a/sys/nfsclient/nfs_diskless.c
+++ b/sys/nfsclient/nfs_diskless.c
@@ -60,6 +60,31 @@ static int inaddr_to_sockaddr(char *ev, struct sockaddr_in *sa);
 static int hwaddr_to_sockaddr(char *ev, struct sockaddr_dl *sa);
 static int decode_nfshandle(char *ev, u_char *fh);
 
+static void
+nfs_parse_options(const char *envopts, struct nfs_diskless *nd)
+{
+	char *opts, *o;
+
+	opts = strdup(envopts, M_TEMP);
+	if (opts == NULL) {
+		printf("nfs_diskless: cannot allocate memory for options\n");
+		return;
+	}
+	for (o = strtok(opts, ":;, "); o != NULL; o = strtok(NULL, ":;, ")) {
+		if (strcmp(o, "soft") == 0)
+			nd->root_args.flags |= NFSMNT_SOFT;
+		else if (strcmp(o, "intr") == 0)
+			nd->root_args.flags |= NFSMNT_INT;
+		else if (strcmp(o, "conn") == 0)
+			nd->root_args.flags |= NFSMNT_NOCONN;
+		else if (strcmp(o, "lockd") == 0)
+			nd->root_args.flags |= NFSMNT_NOLOCKD;
+		else
+			printf("nfs_diskless: unknown option: %s\n", o);
+	}
+	free(opts, M_TEMP);
+}
+
 /*
  * Populate the essential fields in the nfsv3_diskless structure.
  *
@@ -73,6 +98,7 @@ static int decode_nfshandle(char *ev, u_char *fh);
  * boot.nfsroot.server		IP address of root filesystem server
  * boot.nfsroot.path		path of the root filesystem on server
  * boot.nfsroot.nfshandle	NFS handle for root filesystem on server
+ * boot.nfsroot.options		NFS options for the root filesystem
  */
 void
 nfs_setup_diskless(void)
@@ -148,6 +174,10 @@ match_done:
 		strncpy(nd->root_hostnam, cp, MNAMELEN - 1);
 		freeenv(cp);
 	}
+	if ((cp = getenv("boot.nfsroot.options")) != NULL) {
+		nfs_parse_options(cp, nd);
+		freeenv(cp);
+	}
 
 	nfs_diskless_valid = 1;
 }