text-based mount.nfs: Create helpers for invoking mount(2) system call

Add simple helper functions that invoke the mount(2) system call for
text-based mounts.  These look the same right now, but the NFSv2/v3 helper
will become more complex over the following patches as we implement version
and transport protocol fallback.

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 6f57e86ed4633e59f94c4f38903f1b520ce406ad..c048be02713e1f634eee2e9b5b3597e2b2148bd9 100644 (file)
--- a/utils/mount/stropts.c
+++ b/utils/mount/stropts.c
@@ -237,6 +237,80 @@ static int set_mandatory_options(const char *type,
        return 1;
 }
 
+/*
+ * Attempt an NFSv2/3 mount via a mount(2) system call.
+ *
+ * Returns 1 if successful.  Otherwise, returns zero.
+ * "errno" is set to reflect the individual error.
+ */
+static int try_nfs23mount(const char *spec, const char *node,
+                         int flags, struct mount_options *options,
+                         int fake, char **extra_opts)
+{
+       if (po_join(options, extra_opts) == PO_FAILED) {
+               errno = EIO;
+               return 0;
+       }
+
+       if (verbose)
+               printf(_("%s: text-based options: '%s'\n"),
+                       progname, *extra_opts);
+
+       if (fake)
+               return 1;
+
+       if (!mount(spec, node, "nfs",
+                               flags & ~(MS_USER|MS_USERS), *extra_opts))
+               return 1;
+       return 0;
+}
+
+/*
+ * Attempt an NFS v4 mount via a mount(2) system call.
+ *
+ * Returns 1 if successful.  Otherwise, returns zero.
+ * "errno" is set to reflect the individual error.
+ */
+static int try_nfs4mount(const char *spec, const char *node,
+                        int flags, struct mount_options *options,
+                        int fake, char **extra_opts)
+{
+       if (po_join(options, extra_opts) == PO_FAILED) {
+               errno = EIO;
+               return 0;
+       }
+
+       if (verbose)
+               printf(_("%s: text-based options: '%s'\n"),
+                       progname, *extra_opts);
+
+       if (fake)
+               return 1;
+
+       if (!mount(spec, node, "nfs4",
+                               flags & ~(MS_USER|MS_USERS), *extra_opts))
+               return 1;
+       return 0;
+}
+
+/*
+ * Try the mount(2) system call.
+ *
+ * Returns 1 if successful.  Otherwise, returns zero.
+ * "errno" is set to reflect the individual error.
+ */
+static int try_mount(const char *spec, const char *node, const char *type,
+                    int flags, struct mount_options *options, int fake,
+                    char **extra_opts)
+{
+       if (strncmp(type, "nfs4", 4) == 0)
+               return try_nfs4mount(spec, node, flags,
+                                       options, fake, extra_opts);
+       else
+               return try_nfs23mount(spec, node, flags,
+                                       options, fake, extra_opts);
+}
+
 /**
  * nfsmount_string - Mount an NFS file system using C string options
  * @spec: C string specifying remote share to mount ("hostname:path")