[PATCH v2 1/1] nfsdctl: check for listeners before starting threads

[Olga Kornievskaia <okorniev@redhat.com>]

When a thread command is executed and yet no listeners have been
added prior to it, instead of failing with EIO error print an
informative error. Also, "thread 0" command should not error
regardless of the listener status.

Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
---
 utils/nfsdctl/nfsdctl.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/utils/nfsdctl/nfsdctl.c b/utils/nfsdctl/nfsdctl.c
index 6a20d180..ac23e753 100644
--- a/utils/nfsdctl/nfsdctl.c
+++ b/utils/nfsdctl/nfsdctl.c
@@ -162,6 +162,8 @@ static const char *nfsd4_ops[] = {
 	[OP_REMOVEXATTR]	= "OP_REMOVEXATTR",
 };
 
+static int fetch_current_listeners(struct nl_sock *sock);
+
 static int error_handler(struct sockaddr_nl *nla, struct nlmsgerr *err,
 			 void *arg)
 {
@@ -721,6 +723,7 @@ static int threads_func(struct nl_sock *sock, int argc, char **argv)
 	int *pool_threads = NULL;
 	int minthreads = -1;
 	int opt, pools = 0;
+	bool zero_threads = false;
 
 	optind = 1;
 	while ((opt = getopt_long(argc, argv, "hm:", threads_options, NULL)) != -1) {
@@ -762,12 +765,31 @@ static int threads_func(struct nl_sock *sock, int argc, char **argv)
 			}
 
 			pool_threads[i] = strtol(targv[i], &endptr, 0);
+			if (!pool_threads[i])
+				zero_threads = true;
 			if (!endptr || *endptr != '\0') {
 				xlog(L_ERROR, "Invalid threads value %s.", argv[1]);
 				return 1;
 			}
 		}
 	}
+	/* check if there are active listeners added */
+	if (fetch_current_listeners(sock)) {
+		xlog(L_ERROR, "Unable to determine if listeners were added");
+		return 1;
+	}
+	if (!nfsd_socket_count) {
+		if (zero_threads) {
+			/* Note: we can never have a server with threads and no
+			 * listener. If we ever add functionality to remove
+			 * listeners on an active server, we need to revisit this.
+			 */
+			return 0;
+		}
+		xlog(L_ERROR, "No active listeners added, not starting threads");
+		return 1;
+	}
+
 	return threads_doit(sock, cmd, 0, 0, pools, pool_threads, NULL, minthreads);
 }
 
-- 
2.52.0