plugins: Copy memory in qemu_plugin_insn_data

Instead of returning a host pointer, copy the data into
storage provided by the caller.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

plugins/api.c

@@ -216,9 +216,12 @@ qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx)
  * instruction being translated.
  */
 
-const void *qemu_plugin_insn_data(const struct qemu_plugin_insn *insn)
+size_t qemu_plugin_insn_data(const struct qemu_plugin_insn *insn,
+                             void *dest, size_t len)
 {
-    return insn->data->data;
+    len = MIN(len, insn->data->len);
+    memcpy(dest, insn->data->data, len);
+    return len;
 }
 
 size_t qemu_plugin_insn_size(const struct qemu_plugin_insn *insn)