umount.nfs command: Support AF_INET6 server addresses

Replace existing mount option parser in nfsumount.c with the new pmap
stuffer
function nfs_options2pmap().  Mount option parsing for umount.nfs now
works
the same as it does for mount option rewriting in the text-based
mount.nfs
command.

This adds a number of new features:

  1.  The new logic supports resolving AF_INET6 server addresses
  2.  Support is added for the recently introduced "mountaddr" option.
  3.  Parsing numeric option values is much more careful
  4.  Option parsing no longer uses xmalloc/xstrdup, so it won't fail
      silently if memory can't be allocated
  5.  Mount program number set in /etc/rpc is respected
  6.  Mount doesn't exit with EX_USAGE if the hostname lookup fails

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

diff --git a/utils/mount/nfsumount.c b/utils/mount/nfsumount.c
index b2327e03561d9fc41bb4f69a875551b1abd3f864..04990f076a006893a5cdc61c8440697a3fa9be29 100644 (file)
--- a/utils/mount/nfsumount.c
+++ b/utils/mount/nfsumount.c
@@ -34,6 +34,7 @@
 #include "mount.h"
 #include "error.h"
 #include "network.h"
+#include "parse_opt.h"
 #include "parse_dev.h"
 
 #if !defined(MNT_FORCE)
@@ -133,6 +134,100 @@ static int del_mtab(const char *spec, const char *node)
        return EX_FILEIO;
 }
 
+/*
+ * Discover mount server's hostname/address by examining mount options
+ *
+ * Returns a pointer to a string that the caller must free, on
+ * success; otherwise NULL is returned.
+ */
+static char *nfs_umount_hostname(struct mount_options *options,
+                                char *hostname)
+{
+       char *option;
+
+       option = po_get(options, "mountaddr");
+       if (option)
+               goto out;
+       option = po_get(options, "mounthost");
+       if (option)
+               goto out;
+       option = po_get(options, "addr");
+       if (option)
+               goto out;
+
+       return hostname;
+
+out:
+       free(hostname);
+       return strdup(option);
+}
+
+/*
+ * Returns EX_SUCCESS if mount options and device name have been
+ * parsed successfully; otherwise EX_FAIL.
+ */
+static int nfs_umount_do_umnt(struct mount_options *options,
+                             char **hostname, char **dirname)
+{
+       struct sockaddr_storage address;
+       struct sockaddr *sap = (struct sockaddr *)&address;
+       socklen_t salen = sizeof(address);
+       struct pmap nfs_pmap, mnt_pmap;
+
+       nfs_options2pmap(options, &nfs_pmap, &mnt_pmap);
+
+       *hostname = nfs_umount_hostname(options, *hostname);
+       if (!*hostname) {
+               nfs_error(_("%s: out of memory"), progname);
+               return EX_FAIL;
+       }
+
+       if (nfs_name_to_address(*hostname, AF_UNSPEC, sap, &salen)) {
+               if (nfs_advise_umount(sap, salen, &mnt_pmap, dirname) != 0)
+                       return EX_SUCCESS;
+               else
+                       nfs_error(_("%s: Server failed to unmount '%s:%s'"),
+                                       progname, *hostname, *dirname);
+       }
+       return EX_FAIL;
+}
+
+/*
+ * Pick up certain mount options used during the original mount
+ * from /etc/mtab.  The basics include the server's IP address and
+ * the server pathname of the share to unregister.
+ *
+ * These options might also describe the mount port, mount protocol
+ * version, and transport protocol used to punch through a firewall.
+ * We will need this information to get through the firewall again
+ * to do the umount.
+ *
+ * Note that option parsing failures won't necessarily cause the
+ * umount request to fail.  Those values will be left zero in the
+ * pmap tuple.  If the GETPORT call later fails to disambiguate them,
+ * then we fail.
+ */
+static int nfs_umount23(const char *devname, char *string)
+{
+       char *hostname, *dirname;
+       struct mount_options *options;
+       int result = EX_FAIL;
+
+       if (!nfs_parse_devname(devname, &hostname, &dirname))
+               return EX_USAGE;
+
+       options = po_split(string);
+       if (options) {
+               result = nfs_umount_do_umnt(options, &hostname, &dirname);
+               po_destroy(options);
+       } else
+               nfs_error(_("%s: option parsing error"), progname);
+
+       free(hostname);
+       free(dirname);
+       return result;
+}
+
 /*
  * Pick up certain mount options used during the original mount
  * from /etc/mtab.  The basics include the server's IP address and
@@ -350,16 +445,16 @@ int nfsumount(int argc, char *argv[])
        ret = 0;
        if (mc) {
                if (!lazy && strcmp(mc->m.mnt_type, "nfs4") != 0)
-                       /* We ignore the error from do_nfs_umount23.
+                       /* We ignore the error from nfs_umount23.
                         * If the actual umount succeeds (in del_mtab),
                         * we don't want to signal an error, as that
                         * could cause /sbin/mount to retry!
                         */
-                       do_nfs_umount23(mc->m.mnt_fsname, mc->m.mnt_opts);
-               ret = del_mtab(mc->m.mnt_fsname, mc->m.mnt_dir);
+                       nfs_umount23(mc->m.mnt_fsname, mc->m.mnt_opts);
+               ret = del_mtab(mc->m.mnt_fsname, mc->m.mnt_dir) ?: ret;
        } else if (*spec != '/') {
                if (!lazy)
-                       ret = do_nfs_umount23(spec, "tcp,v3");
+                       ret = nfs_umount23(spec, "tcp,v3");
        } else
                ret = del_mtab(NULL, spec);