+ return result;
+}
+
+/*
+ * This is a single pass through the fg/bg loop.
+ *
+ * Returns TRUE if successful, otherwise FALSE.
+ * "errno" is set to reflect the individual error.
+ */
+static int nfs_try_mount(struct nfsmount_info *mi)
+{
+ int result = 0;
+
+ switch (mi->version) {
+ case 0:
+ if (linux_version_code() > MAKE_VERSION(2, 6, 31)) {
+ errno = 0;
+ result = nfs_try_mount_v4(mi);
+ if (errno != EPROTONOSUPPORT) {
+ /*
+ * To deal with legacy Linux servers that don't
+ * automatically export a pseudo root, retry
+ * ENOENT errors using version 3. And for
+ * Linux servers prior to 2.6.25, retry EPERM
+ */
+ if (errno != ENOENT && errno != EPERM)
+ break;
+ }
+ }
+ case 2:
+ case 3:
+ result = nfs_try_mount_v3v2(mi);
+ break;
+ case 4:
+ result = nfs_try_mount_v4(mi);
+ break;
+ default:
+ errno = EIO;
+ }
+
+ return result;
+}
+
+/*
+ * Distinguish between permanent and temporary errors.
+ *
+ * Basically, we retry if communication with the server has
+ * failed so far, but fail immediately if there is a local
+ * error (like a bad mount option).
+ *
+ * ESTALE is also a temporary error because some servers
+ * return ESTALE when a share is temporarily offline.
+ *
+ * Returns 1 if we should fail immediately, or 0 if we
+ * should retry.
+ */
+static int nfs_is_permanent_error(int error)
+{
+ switch (error) {
+ case ESTALE:
+ case ETIMEDOUT:
+ case ECONNREFUSED:
+ return 0; /* temporary */
+ default:
+ return 1; /* permanent */
+ }
+}
+
+/*
+ * Handle "foreground" NFS mounts.
+ *
+ * Retry the mount request for as long as the 'retry=' option says.
+ *
+ * Returns a valid mount command exit code.
+ */
+static int nfsmount_fg(struct nfsmount_info *mi)
+{
+ unsigned int secs = 1;
+ time_t timeout;
+
+ timeout = nfs_parse_retry_option(mi->options,
+ NFS_DEF_FG_TIMEOUT_MINUTES);
+ if (verbose)
+ printf(_("%s: timeout set for %s"),
+ progname, ctime(&timeout));
+
+ for (;;) {
+ if (nfs_try_mount(mi))
+ return EX_SUCCESS;
+
+ if (nfs_is_permanent_error(errno))
+ break;
+
+ if (time(NULL) > timeout) {
+ errno = ETIMEDOUT;
+ break;
+ }
+
+ if (errno != ETIMEDOUT) {
+ if (sleep(secs))
+ break;
+ secs <<= 1;
+ if (secs > 10)
+ secs = 10;
+ }
+ };
+
+ mount_error(mi->spec, mi->node, errno);
+ return EX_FAIL;
+}
+
+/*
+ * Handle "background" NFS mount [first try]
+ *
+ * Returns a valid mount command exit code.
+ *
+ * EX_BG should cause the caller to fork and invoke nfsmount_child.
+ */
+static int nfsmount_parent(struct nfsmount_info *mi)
+{
+ if (nfs_try_mount(mi))
+ return EX_SUCCESS;
+
+ if (nfs_is_permanent_error(errno)) {
+ mount_error(mi->spec, mi->node, errno);
+ return EX_FAIL;
+ }
+
+ sys_mount_errors(mi->hostname, errno, 1, 1);
+ return EX_BG;
+}
+
+/*
+ * Handle "background" NFS mount [retry daemon]
+ *
+ * Returns a valid mount command exit code: EX_SUCCESS if successful,
+ * EX_FAIL if a failure occurred. There's nothing to catch the
+ * error return, though, so we use sys_mount_errors to log the
+ * failure.
+ */
+static int nfsmount_child(struct nfsmount_info *mi)
+{
+ unsigned int secs = 1;
+ time_t timeout;
+
+ timeout = nfs_parse_retry_option(mi->options,
+ NFS_DEF_BG_TIMEOUT_MINUTES);
+
+ for (;;) {
+ if (sleep(secs))
+ break;
+ secs <<= 1;
+ if (secs > 120)
+ secs = 120;
+
+ if (nfs_try_mount(mi))
+ return EX_SUCCESS;
+
+ if (nfs_is_permanent_error(errno))
+ break;
+
+ if (time(NULL) > timeout)
+ break;
+
+ sys_mount_errors(mi->hostname, errno, 1, 1);
+ };
+
+ sys_mount_errors(mi->hostname, errno, 1, 0);
+ return EX_FAIL;
+}
+
+/*
+ * Handle "background" NFS mount
+ *
+ * Returns a valid mount command exit code.
+ */
+static int nfsmount_bg(struct nfsmount_info *mi)
+{
+ if (!mi->child)
+ return nfsmount_parent(mi);
+ else
+ return nfsmount_child(mi);
+}
+
+/*
+ * Process mount options and try a mount system call.
+ *
+ * Returns a valid mount command exit code.
+ */
+static const char *nfs_background_opttbl[] = {
+ "bg",
+ "fg",
+ NULL,
+};
+
+static int nfsmount_start(struct nfsmount_info *mi)
+{
+ if (!nfs_validate_options(mi))
+ return EX_FAIL;
+
+ if (po_rightmost(mi->options, nfs_background_opttbl) == 0)
+ return nfsmount_bg(mi);
+ else
+ return nfsmount_fg(mi);
+}
+
+/**
+ * nfsmount_string - Mount an NFS file system using C string options
+ * @spec: C string specifying remote share to mount ("hostname:path")
+ * @node: C string pathname of local mounted-on directory
+ * @type: C string that represents file system type ("nfs" or "nfs4")
+ * @flags: MS_ style mount flags
+ * @extra_opts: pointer to C string containing fs-specific mount options
+ * (input and output argument)
+ * @fake: flag indicating whether to carry out the whole operation
+ * @child: one if this is a mount daemon (bg)
+ */
+int nfsmount_string(const char *spec, const char *node, const char *type,
+ int flags, char **extra_opts, int fake, int child)
+{
+ struct nfsmount_info mi = {
+ .spec = spec,
+ .node = node,
+ .type = type,
+ .extra_opts = extra_opts,
+ .flags = flags,
+ .fake = fake,
+ .child = child,
+ };
+ int retval = EX_FAIL;
+
+ mi.options = po_split(*extra_opts);
+ if (mi.options) {
+ retval = nfsmount_start(&mi);
+ po_destroy(mi.options);
+ } else
+ nfs_error(_("%s: internal option parsing error"), progname);
+
+ free(mi.hostname);