[memfile] Add support for faking files in memory

src/main/hooklib/memfile.h

@@ -0,0 +1,42 @@
+#ifndef HOOKLIB_MEMFILE_H
+#define HOOKLIB_MEMFILE_H
+
+#include <stdint.h>
+#include <windows.h>
+
+#include "hook/iohook.h"
+
+/**
+ * memfile allows you to stub read-only files in memory.
+ */
+
+/**
+ * This hooks required functions and sets up the hook array.
+ * Please remember to install the irp below.
+ */
+void memfile_hook_init(void);
+
+void memfile_hook_fini(void);
+
+enum memfile_hook_path_mode {
+    ABSOLUTE_MATCH = 0x1,
+    ENDING_MATCH = 0x2,
+};
+
+/**
+ * Adds the specified path to the list of files to hook
+ *
+ * @param path path to hook
+ * @param path_mode path matching mode (1: abs, 2: ending)
+ * @param data file contents (buffer must exist until fini is called)
+ * @param sz size of file
+ */
+void memfile_hook_add_fd(
+    const char *path, enum memfile_hook_path_mode path_mode, const void *data, uint32_t sz);
+
+/**
+ * iohook dispatch function. Needs to be installed.
+ */
+HRESULT memfile_hook_dispatch_irp(struct irp *irp);
+
+#endif