ctdb-cluster-mutex: Separate out command and file handling

This code is difficult to read and there really is no common code
between the 2 cases.  For example, there is no need to split a
filename into words.  Separating each of the 2 cases into its own
function makes the logic much easier to understand.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13800

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

Autobuild-User(master): Amitay Isaacs <amitay@samba.org>
Autobuild-Date(master): Mon Feb 25 03:40:16 CET 2019 on sn-devel-144

(cherry picked from commit c93430fe8fe530a55b9a04cf6cc660c3d420e333)
(cherry picked from commit d5131afc533102ed5adfb147bf1a316e51810729)

1 files changed, 71 insertions, 42 deletions

diff --git a/ctdb/server/ctdb_cluster_mutex.c b/ctdb/server/ctdb_cluster_mutex.c
index 330d5fd1d90..2e3cb8112ad 100644
--- a/ctdb/server/ctdb_cluster_mutex.c
+++ b/ctdb/server/ctdb_cluster_mutex.c
@@ -118,72 +118,101 @@ static void cluster_mutex_handler(struct tevent_context *ev,
 
 static char cluster_mutex_helper[PATH_MAX+1] = "";
 
-static bool cluster_mutex_helper_args(TALLOC_CTX *mem_ctx,
-				      const char *argstring, char ***argv)
+static bool cluster_mutex_helper_args_file(TALLOC_CTX *mem_ctx,
+					   const char *argstring,
+					   char ***argv)
 {
-	int nargs, i, ret, n;
-	bool is_command = false;
+	bool ok;
 	char **args = NULL;
-	char *strv = NULL;
-	char *t = NULL;
 
-	if (argstring != NULL && argstring[0] == '!') {
-		/* This is actually a full command */
-		is_command = true;
-		t = discard_const(&argstring[1]);
-	} else {
-		is_command = false;
-		t = discard_const(argstring);
+	ok = ctdb_set_helper("cluster mutex helper",
+			     cluster_mutex_helper,
+			     sizeof(cluster_mutex_helper),
+			     "CTDB_CLUSTER_MUTEX_HELPER",
+			     CTDB_HELPER_BINDIR,
+			     "ctdb_mutex_fcntl_helper");
+	if (! ok) {
+		DBG_ERR("ctdb exiting with error: "
+			"Unable to set cluster mutex helper\n");
+		exit(1);
 	}
 
-	ret = strv_split(mem_ctx, &strv, t, " \t");
-	if (ret != 0) {
-		DEBUG(DEBUG_ERR,
-		      ("Unable to parse mutex helper string \"%s\" (%s)\n",
-		       argstring, strerror(ret)));
+
+	/* Array includes default helper, file and NULL */
+	args = talloc_array(mem_ctx, char *, 3);
+	if (args == NULL) {
+		DBG_ERR("Memory allocation error\n");
 		return false;
 	}
-	n = strv_count(strv);
 
-	args = talloc_array(mem_ctx, char *, n + (is_command ? 1 : 2));
+	args[0] = cluster_mutex_helper;
 
-	if (args == NULL) {
-		DEBUG(DEBUG_ERR,(__location__ " out of memory\n"));
+	args[1] = talloc_strdup(args, argstring);
+	if (args[1] == NULL) {
+		DBG_ERR("Memory allocation error\n");
 		return false;
 	}
 
-	nargs = 0;
-
-	if (! is_command) {
-		if (!ctdb_set_helper("cluster mutex helper",
-				     cluster_mutex_helper,
-				     sizeof(cluster_mutex_helper),
-				     "CTDB_CLUSTER_MUTEX_HELPER",
-				     CTDB_HELPER_BINDIR,
-				     "ctdb_mutex_fcntl_helper")) {
-			DEBUG(DEBUG_ERR,("ctdb exiting with error: %s\n",
-					 __location__
-					 " Unable to set cluster mutex helper\n"));
-			exit(1);
-		}
+	args[2] = NULL;
+
+	*argv = args;
+	return true;
+}
 
-		args[nargs++] = cluster_mutex_helper;
+static bool cluster_mutex_helper_args_cmd(TALLOC_CTX *mem_ctx,
+					  const char *argstring,
+					  char ***argv)
+{
+	int i, ret, n;
+	char **args = NULL;
+	char *strv = NULL;
+	char *t = NULL;
+
+	ret = strv_split(mem_ctx, &strv, argstring, " \t");
+	if (ret != 0) {
+		D_ERR("Unable to parse mutex helper command \"%s\" (%s)\n",
+		      argstring,
+		      strerror(ret));
+		return false;
 	}
+	n = strv_count(strv);
+
+	/* Extra slot for NULL */
+	args = talloc_array(mem_ctx, char *, n + 1);
+	if (args == NULL) {
+		DBG_ERR("Memory allocation error\n");
+		return false;
+	}
+
+	talloc_steal(args, strv);
 
 	t = NULL;
-	for (i = 0; i < n; i++) {
-		/* Don't copy, just keep cmd_args around */
+	for (i = 0 ; i < n; i++) {
 		t = strv_next(strv, t);
-		args[nargs++] = t;
+		args[i] = t;
 	}
 
-	/* Make sure last argument is NULL */
-	args[nargs] = NULL;
+	args[n] = NULL;
 
 	*argv = args;
 	return true;
 }
 
+static bool cluster_mutex_helper_args(TALLOC_CTX *mem_ctx,
+				      const char *argstring,
+				      char ***argv)
+{
+	bool ok;
+
+	if (argstring != NULL && argstring[0] == '!') {
+		ok = cluster_mutex_helper_args_cmd(mem_ctx, &argstring[1], argv);
+	} else {
+		ok = cluster_mutex_helper_args_file(mem_ctx, argstring, argv);
+	}
+
+	return ok;
+}
+
 struct ctdb_cluster_mutex_handle *
 ctdb_cluster_mutex(TALLOC_CTX *mem_ctx,
 		   struct ctdb_context *ctdb,