text-based mount.nfs: Add rewrite_mount_options() function

Introduce a function for probing the server for what it supports, and then
rewriting the mount options using the probe results.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Neil Brown <neilb@suse.de>

diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c
index c048be02713e1f634eee2e9b5b3597e2b2148bd9..fcc5b98ef5ec769585e4eb32c0eff61453020e31 100644 (file)
--- a/utils/mount/stropts.c
+++ b/utils/mount/stropts.c
@@ -237,6 +237,136 @@ static int set_mandatory_options(const char *type,
        return 1;
 }
 
+/*
+ * Reconstruct the mount option string based on a portmapper probe
+ * of the server.  Returns one if the server's portmapper returned
+ * something we can use, otherwise zero.
+ *
+ * To handle version and transport protocol fallback properly, we
+ * need to parse some of the mount options in order to set up a
+ * portmap probe.  Mount options that rewrite_mount_options()
+ * doesn't recognize are left alone.
+ *
+ * Returns a new group of mount options if successful; otherwise
+ * NULL is returned if some failure occurred.
+ */
+static struct mount_options *rewrite_mount_options(char *str)
+{
+       struct mount_options *options;
+       char *option, new_option[64];
+       clnt_addr_t mnt_server = { };
+       clnt_addr_t nfs_server = { };
+       int p;
+
+       options = po_split(str);
+       if (!options)
+               return NULL;
+
+       option = po_get(options, "addr");
+       if (option) {
+               nfs_server.saddr.sin_family = AF_INET;
+               if (!inet_aton((const char *)option, &nfs_server.saddr.sin_addr))
+                       goto err;
+       } else
+               goto err;
+
+       option = po_get(options, "mountaddr");
+       if (option) {
+               mnt_server.saddr.sin_family = AF_INET;
+               if (!inet_aton((const char *)option, &mnt_server.saddr.sin_addr))
+                       goto err;
+       } else
+               memcpy(&mnt_server.saddr, &nfs_server.saddr,
+                               sizeof(mnt_server.saddr));
+
+       option = po_get(options, "mountport");
+       if (option)
+               mnt_server.pmap.pm_port = atoi(option);
+       mnt_server.pmap.pm_prog = MOUNTPROG;
+       option = po_get(options, "mountprog");
+       if (option)
+               mnt_server.pmap.pm_prog = atoi(option);
+       option = po_get(options, "mountvers");
+       if (option)
+               mnt_server.pmap.pm_vers = atoi(option);
+
+       option = po_get(options, "port");
+       if (option) {
+               nfs_server.pmap.pm_port = atoi(option);
+               po_remove_all(options, "port");
+       }
+       nfs_server.pmap.pm_prog = NFS_PROGRAM;
+       option = po_get(options, "nfsprog");
+       if (option)
+               nfs_server.pmap.pm_prog = atoi(option);
+
+       option = po_get(options, "nfsvers");
+       if (option) {
+               nfs_server.pmap.pm_vers = atoi(option);
+               po_remove_all(options, "nfsvers");
+       }
+       option = po_get(options, "vers");
+       if (option) {
+               nfs_server.pmap.pm_vers = atoi(option);
+               po_remove_all(options, "vers");
+       }
+       option = po_get(options, "proto");
+       if (option) {
+               if (strcmp(option, "tcp") == 0) {
+                       nfs_server.pmap.pm_prot = IPPROTO_TCP;
+                       po_remove_all(options, "proto");
+               }
+               if (strcmp(option, "udp") == 0) {
+                       nfs_server.pmap.pm_prot = IPPROTO_UDP;
+                       po_remove_all(options, "proto");
+               }
+       }
+       p = po_rightmost(options, "tcp", "udp");
+       switch (p) {
+       case PO_KEY2_RIGHTMOST:
+               nfs_server.pmap.pm_prot = IPPROTO_UDP;
+               break;
+       case PO_KEY1_RIGHTMOST:
+               nfs_server.pmap.pm_prot = IPPROTO_TCP;
+               break;
+       }
+       po_remove_all(options, "tcp");
+       po_remove_all(options, "udp");
+
+       if (!probe_bothports(&mnt_server, &nfs_server)) {
+               rpc_mount_errors("rpcbind", 0, 0);
+               goto err;
+       }
+
+       snprintf(new_option, sizeof(new_option) - 1,
+                "nfsvers=%lu", nfs_server.pmap.pm_vers);
+       if (po_append(options, new_option) == PO_FAILED)
+               goto err;
+
+       if (nfs_server.pmap.pm_prot == IPPROTO_TCP)
+               snprintf(new_option, sizeof(new_option) - 1,
+                        "proto=tcp");
+       else
+               snprintf(new_option, sizeof(new_option) - 1,
+                        "proto=udp");
+       if (po_append(options, new_option) == PO_FAILED)
+               goto err;
+
+       if (nfs_server.pmap.pm_port != NFS_PORT) {
+               snprintf(new_option, sizeof(new_option) - 1,
+                        "port=%lu", nfs_server.pmap.pm_port);
+               if (po_append(options, new_option) == PO_FAILED)
+                       goto err;
+
+       }
+
+       return options;
+
+err:
+       po_destroy(options);
+       return NULL;
+}
+
 /*
  * Attempt an NFSv2/3 mount via a mount(2) system call.
  *