1// Copyright 2018 The Fuchsia Authors
2//
3// Use of this source code is governed by a MIT-style
4// license that can be found in the LICENSE file or at
5// https://opensource.org/licenses/MIT
6
7#include <object/buffer_chain.h>
8
9// Makes a const void* look like a user_in_ptr<const void>.
10//
11// Sometimes we need to copy data from kernel space. KernelPtrAdapter allows us to implement the
12// copy logic once for both const void* and user_in_ptr<const void>.
13class KernelPtrAdapter {
14public:
15    explicit KernelPtrAdapter(const void* p)
16        : p_(p) {}
17    zx_status_t copy_array_from_user(void* dst, size_t count) const {
18        memcpy(dst, p_, count);
19        return ZX_OK;
20    }
21    KernelPtrAdapter byte_offset(size_t offset) const {
22        return KernelPtrAdapter(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(p_) + offset));
23    }
24
25private:
26    const void* p_;
27};
28
29zx_status_t BufferChain::CopyInKernel(const void* src, size_t dst_offset, size_t size) {
30    return CopyInCommon(KernelPtrAdapter(src), dst_offset, size);
31}
32
33template zx_status_t BufferChain::CopyInCommon(user_in_ptr<const void> src, size_t dst_offset,
34                                               size_t size);
35