param: make sure the name is a string literal.

We're using a macro anyway, so appending "" make it a compile-time check.

Complicates testing a bit, since we actually use generated names there.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/params.c

@@ -9,7 +9,7 @@
 
 struct param {
 	const tal_t *ctx;
-	char *name;
+	const char *name;
 	bool is_set;
 	param_cb cb;
 	void *arg;
@@ -17,7 +17,8 @@ struct param {
 };
 
 struct param *param_add_(const tal_t *ctx,
-			 char *name, param_cb cb, void *arg, size_t argsize)
+			 const char *name, param_cb cb, void *arg,
+			 size_t argsize)
 {
 #if DEVELOPER
 	assert(name);
@@ -27,7 +28,7 @@ struct param *param_add_(const tal_t *ctx,
 	struct param *last = tal(tmpctx, struct param);
 	last->ctx = ctx;
 	last->is_set = false;
-	last->name = tal_strdup(last, name);
+	last->name = name;
 	last->cb = cb;
 	last->arg = arg;
 	last->argsize = argsize;
@@ -37,13 +38,14 @@ struct param *param_add_(const tal_t *ctx,
 	return last;
 }
 
-struct param *param_opt_add_(const tal_t *ctx, char *name, const jsmntok_t **tok)
+struct param *param_opt_add_(const tal_t *ctx, const char *name,
+			     const jsmntok_t **tok)
 {
 	struct param *last = tal(tmpctx, struct param);
 	assert(ctx);
 	last->ctx = ctx;
 	last->is_set = false;
-	last->name = tal_strdup(last, name);
+	last->name = name;
 	last->cb = (param_cb)json_tok_tok;
 	last->arg = tok;
 	last->argsize = sizeof(*tok);

lightningd/params.h

@@ -60,7 +60,7 @@ typedef bool(*param_cb)(const char *buffer, const jsmntok_t *tok, void *arg);
  * Returns an opaque pointer that can be later used in param_is_set().
  */
 #define param_req(name, cb, arg)         \
-		  param_add_(NULL, name,			     \
+		  param_add_(NULL, name"",			     \
 			     typesafe_cb_preargs(bool, void *,       \
 						 (cb), (arg),        \
 						 const char *,       \
@@ -70,17 +70,17 @@ typedef bool(*param_cb)(const char *buffer, const jsmntok_t *tok, void *arg);
  * Same as above but for optional parameters.
  */
 #define param_opt(ctx, name, cb, arg)	  \
-		  param_add_(ctx, name,				     \
+		  param_add_(ctx, name"",			     \
 			     typesafe_cb_preargs(bool, void *,       \
 						 (cb), *(arg),       \
 						 const char *,       \
 						 const jsmntok_t *), \
 			     (arg), sizeof(**arg))
-struct param * param_add_(const tal_t *ctx, char *name, param_cb cb, void *arg, size_t argsize);
+struct param * param_add_(const tal_t *ctx, const char *name, param_cb cb, void *arg, size_t argsize);
 
 #define param_opt_tok(ctx, name, arg)		\
-	param_opt_add_(ctx, name, arg)
+	param_opt_add_(ctx, name"", arg)
 
-struct param *param_opt_add_(const tal_t *ctx, char *name, const jsmntok_t **tok);
+struct param *param_opt_add_(const tal_t *ctx, const char *name, const jsmntok_t **tok);
 
 #endif /* LIGHTNING_LIGHTNINGD_PARAMS_H */

lightningd/test/run-params.c

@@ -318,21 +318,6 @@ static void bad_programmer(void)
 		assert(false);
 	}
 
-	/* check for NULL input */
-	if (setjmp(jump) == 0) {
-		param_parse(cmd, j->buffer, j->toks,
-			    param_req(NULL, json_tok_u64, &ival), NULL);
-		restore_assert();
-		assert(false);
-	}
-
-	if (setjmp(jump) == 0) {
-		param_parse(cmd, j->buffer, j->toks,
-			    param_req(NULL, json_tok_u64, &ival), NULL);
-		restore_assert();
-		assert(false);
-	}
-
 	if (setjmp(jump) == 0) {
 		param_parse(cmd, j->buffer, j->toks,
 			    param_req("u64", NULL, &ival), NULL);
@@ -364,12 +349,18 @@ static void add_members(struct param **params,
 			struct json_result *obj,
 			struct json_result *arr, unsigned int *ints)
 {
-	char name[256];
 	for (int i = 0; i < tal_count(ints); ++i) {
-		sprintf(name, "%d", i);
+		char *name = tal_fmt(tmpctx, "%i", i);
 		json_add_num(obj, name, i);
 		json_add_num(arr, NULL, i);
-		params[i] = param_req(name, json_tok_number, &ints[i]);
+		/* Since name is not a literal, we do this manually. */
+		params[i] = param_add_(NULL, name,
+				       typesafe_cb_preargs(bool, void *,
+							   json_tok_number,
+							   &ints[i],
+							   const char *,
+							   const jsmntok_t *),
+				       &ints[i], 0);
 		tal_steal(params, params[i]);
 	}
 }