add dynamic library interface to enable testing
Add interface defining the methods for dynamic linking to enable
testing.
Change-Id: If4d090d3cedc019b426435a1f651191803bfc1a9
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/internal/sys.hpp b/internal/sys.hpp
new file mode 100644
index 0000000..e0a02bf
--- /dev/null
+++ b/internal/sys.hpp
@@ -0,0 +1,54 @@
+#pragma once
+
+namespace blobs
+{
+
+namespace internal
+{
+/**
+ * Interface to the dynamic library loader.
+ */
+class DlSysInterface
+{
+ public:
+ virtual ~DlSysInterface() = default;
+
+ /**
+ * obtain error diagnostic for functions in the dlopen API
+ *
+ * @return the error details
+ */
+ virtual const char* dlerror() const = 0;
+
+ /**
+ * open a shared object
+ *
+ * @param[in] filename - the path to the shared object or the filename to
+ * for searching
+ * @param[in] flags - the flags
+ * @return a handle to the shared object (null on failure)
+ */
+ virtual void* dlopen(const char* filename, int flags) const = 0;
+
+ /**
+ * obtain address of a symbol in a shared object or executable
+ *
+ * @param[in] handle - pointer to shared object
+ * @param[in] symbol - name of the symbol to find
+ * @return the address of the symbol if found (null otherwise)
+ */
+ virtual void* dlsym(void* handle, const char* symbol) const = 0;
+};
+
+class DlSysImpl : public DlSysInterface
+{
+ public:
+ const char* dlerror() const override;
+ void* dlopen(const char* filename, int flags) const override;
+ void* dlsym(void* handle, const char* symbol) const override;
+};
+
+extern DlSysImpl dlsys_impl;
+
+} // namespace internal
+} // namespace blobs