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.

diff --git a/src/helper/command.c b/src/helper/command.c
index 4b7d8cb9b4d86f282806a0ab9341eab0f19c7c3a..ce857dd6c21c32152f79687dc544bc0d54674228 100644 (file)
--- 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);