diff --git a/script/user_model.c b/script/user_model.c
new file mode 100644
index 000000000..a933d735c
--- /dev/null
+++ b/script/user_model.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+void *realloc(void *ptr, size_t size);
+void *memmove(void *dest, const void *src, size_t n);
+size_t strlen(const char *s);
+
+typedef struct va_list_str *va_list;
+
+typedef struct git_vector {
+	void **contents;
+	size_t length;
+} git_vector;
+
+typedef struct git_buf {
+	char *ptr;
+	size_t asize, size;
+} git_buf;
+
+int git_vector_insert(git_vector *v, void *element)
+{
+	if (!v)
+		__coverity_panic__();
+
+	v->contents = realloc(v->contents, ++v->length);
+	if (!v->contents)
+		__coverity_panic__();
+	v->contents[v->length] = element;
+
+	return 0;
+}
+
+int git_buf_len(const struct git_buf *buf)
+{
+	return strlen(buf->ptr);
+}
+
+int git_buf_vprintf(git_buf *buf, const char *format, va_list ap)
+{
+    char ch, *s;
+    size_t len;
+
+    __coverity_string_null_sink__(format);
+    __coverity_string_size_sink__(format);
+
+    ch = *format;
+    ch = *(char *)ap;
+
+    buf->ptr = __coverity_alloc__(len);
+    __coverity_writeall__(buf->ptr);
+    buf->size = len;
+
+    return 0;
+}
+
+int git_buf_put(git_buf *buf, const char *data, size_t len)
+{
+    buf->ptr = __coverity_alloc__(buf->size + len + 1);
+    memmove(buf->ptr + buf->size, data, len);
+    buf->size += len;
+    buf->ptr[buf->size + len] = 0;
+    return 0;
+}
+
+int git_buf_set(git_buf *buf, const void *data, size_t len)
+{
+    buf->ptr = __coverity_alloc__(len + 1);
+    memmove(buf->ptr, data, len);
+    buf->size = len + 1;
+    return 0;
+}