add error checking in command_new

Adds checks for memory allocation failures.  Started to use calloc()
instead of malloc()/memset(), but I got carried away.  This kind of work
should be done throughout the tree, but it's almost hopeless at present.

1 files changed, 30 insertions, 20 deletions

diff --git a/src/helper/command.c b/src/helper/command.c
index 4b7d8cb9..ce857dd6 100644
--- a/src/helper/command.c
+++ b/src/helper/command.c
@@ -253,19 +253,44 @@ static struct command **command_list_for_parent(
 	return parent ? &parent->children : &cmd_ctx->commands;
 }
 
+static void command_free(struct command *c)
+{
+	/// @todo if command has a handler, unregister its jim command!
+
+	while (NULL != c->children)
+	{
+		struct command *tmp = c->children;
+		c->children = tmp->next;
+		command_free(tmp);
+	}
+
+	if (c->name)
+		free(c->name);
+	if (c->help)
+		free((void*)c->help);
+	if (c->usage)
+		free((void*)c->usage);
+	free(c);
+}
+
 static struct command *command_new(struct command_context *cmd_ctx,
 		struct command *parent, const struct command_registration *cr)
 {
 	assert(cr->name);
 
-	struct command *c = malloc(sizeof(struct command));
-	memset(c, 0, sizeof(struct command));
+	struct command *c = calloc(1, sizeof(struct command));
+	if (NULL == c)
+		return NULL;
 
 	c->name = strdup(cr->name);
 	if (cr->help)
 		c->help = strdup(cr->help);
 	if (cr->usage)
 		c->usage = strdup(cr->usage);
+
+	if (!c->name || (cr->help && !c->help) || (cr->usage && !c->usage))
+		goto command_new_error;
+
 	c->parent = parent;
 	c->handler = cr->handler;
 	c->jim_handler = cr->jim_handler;
@@ -275,25 +300,10 @@ static struct command *command_new(struct command_context *cmd_ctx,
 	command_add_child(command_list_for_parent(cmd_ctx, parent), c);
 
 	return c;
-}
-static void command_free(struct command *c)
-{
-	/// @todo if command has a handler, unregister its jim command!
 
-	while (NULL != c->children)
-	{
-		struct command *tmp = c->children;
-		c->children = tmp->next;
-		command_free(tmp);
-	}
-
-	if (c->name)
-		free(c->name);
-	if (c->help)
-		free((void*)c->help);
-	if (c->usage)
-		free((void*)c->usage);
-	free(c);
+command_new_error:
+	command_free(c);
+	return NULL;
 }
 
 static int command_unknown(Jim_Interp *interp, int argc, Jim_Obj *const *argv);