add ctrl_cmd_parse2() to return parsing errors

If a control command fails to parse, we so far discard specific error messages
and instead send just "Command parser error".

In ctrl_cmd_parse() we actually compose detailed error replies, but in the end
simply talloc_free() them and return NULL.

A first step to report these errors to the ctrl command issuer is to not return
NULL and instead return the cmd with type = CTRL_TYPE_ERROR. Add
ctrl_cmd_parse2() to return such instead of NULL.

To stay API compatible, provide ctrl_cmd_parse2() to return a cmd on errors.
ctrl_cmd_parse() retains identical behavior but becomes just a simple wrapper
around ctrl_cmd_parse2() which discards the cmd on error.

No need really to deprecate ctrl_cmd_parse() yet; especially as long as
compiler warnings might break jenkins builds.

Change-Id: I5047c9f977d70b03eea77cbcfd2b96d43ea46880

1 files changed, 16 insertions, 2 deletions

diff --git a/src/ctrl/control_cmd.c b/src/ctrl/control_cmd.c
index f6164795..c2ce2be4 100644
--- a/src/ctrl/control_cmd.c
+++ b/src/ctrl/control_cmd.c
@@ -269,8 +269,23 @@ err:
 	return NULL;
 }
 
+/*! Parse CTRL command struct from msgb, return NULL on any error.
+ * The caller is responsible to talloc_free() the returned struct pointer. */
 struct ctrl_cmd *ctrl_cmd_parse(void *ctx, struct msgb *msg)
 {
+	struct ctrl_cmd *res = ctrl_cmd_parse2(ctx, msg);
+	if (res->type == CTRL_TYPE_ERROR) {
+		talloc_free(res);
+		return NULL;
+	}
+	return res;
+}
+
+/*! Parse CTRL command struct from msgb, return ctrl->type == CTRL_TYPE_ERROR and an error message in
+ * ctrl->reply on any error.
+ * The caller is responsible to talloc_free() the returned struct pointer. */
+struct ctrl_cmd *ctrl_cmd_parse2(void *ctx, struct msgb *msg)
+{
 	char *str, *tmp, *saveptr = NULL;
 	char *var, *val;
 	struct ctrl_cmd *cmd;
@@ -382,8 +397,7 @@ oom:
 	cmd->id = "err";
 	cmd->reply = "OOM";
 err:
-	talloc_free(cmd);
-	return NULL;
+	return cmd;
 }
 
 struct msgb *ctrl_cmd_make(struct ctrl_cmd *cmd)