Fix potential memory leaks by `rb_imemo_tmpbuf_auto_free_pointer`

This function has been used wrongly always at first, "allocate a
buffer then wrap it with tmpbuf".  This order can cause a memory
leak, as tmpbuf creation also can raise a NoMemoryError exception.
The right order is "create a tmpbuf then allocate&wrap a buffer".
So the argument of this function is rather harmful than just
useless.

TODO:
* Rename this function to more proper name, as it is not used
  "temporary" (function local) purpose.
* Allocate and wrap at once safely, like `ALLOCV`.

1 files changed, 2 insertions, 2 deletions

diff --git a/process.c b/process.c
index fa5de27273..00e140eda7 100644
--- a/process.c
+++ b/process.c
@@ -2691,8 +2691,8 @@ open_func(void *ptr)
 static void
 rb_execarg_allocate_dup2_tmpbuf(struct rb_execarg *eargp, long len)
 {
-    VALUE tmpbuf = rb_imemo_tmpbuf_auto_free_pointer(NULL);
-    ((rb_imemo_tmpbuf_t *)tmpbuf)->ptr = ruby_xmalloc(run_exec_dup2_tmpbuf_size(len));
+    VALUE tmpbuf = rb_imemo_tmpbuf_auto_free_pointer();
+    rb_imemo_tmpbuf_set_ptr(tmpbuf, ruby_xmalloc(run_exec_dup2_tmpbuf_size(len)));
     eargp->dup2_tmpbuf = tmpbuf;
 }