vcon_svr

// vi:set ft=cpp: -*- Mode: C++ -*-
/*
 * (c) 2008-2011 Alexander Warg <warg@os.inf.tu-dresden.de>,
 *               Torsten Frenzel <frenzel@os.inf.tu-dresden.de>
 *               Adam Lackorzynski <adam@os.inf.tu-dresden.de>
 *     economic rights: Technische Universität Dresden (Germany)
 *
 * License: see LICENSE.spdx (in this directory or the directories above)
 */
#pragma once
 
#include <l4/sys/types.h>
#include <l4/sys/vcon>
#include <l4/sys/cxx/ipc_legacy>
#include <l4/cxx/minmax>
 
namespace L4Re { namespace Util {

template< typename SVR >
class Vcon_svr
{
public:
  L4_RPC_LEGACY_DISPATCH(L4::Vcon);
 
  l4_msgtag_t op_dispatch(l4_utcb_t *utcb, l4_msgtag_t tag, L4::Vcon::Rights)
  {
    l4_msg_regs_t *m = l4_utcb_mr_u(utcb);
    L4::Opcode op = m->mr[0] & 0xFFFF;
 
    switch (op)
      {
      case L4_VCON_WRITE_OP:
        if (tag.words() < 3)
          return l4_msgtag(-L4_ENOREPLY, 0, 0, 0);
 
        this_vcon()->vcon_write(reinterpret_cast<char const *>(&m->mr[2]),
                                m->mr[1]);
        return l4_msgtag(-L4_ENOREPLY, 0, 0, 0);
 
      case L4_VCON_SET_ATTR_OP:
        {
          if (tag.words() < 4)
            return l4_msgtag(-L4_EINVAL, 0, 0, 0);
 
          auto attr = reinterpret_cast<l4_vcon_attr_t const *>(&m->mr[1]);
          return l4_msgtag(this_vcon()->vcon_set_attr(attr), 0, 0, 0);
        }
      case L4_VCON_GET_ATTR_OP:
        {
          auto attr = reinterpret_cast<l4_vcon_attr_t *>(&m->mr[1]);
          return l4_msgtag(this_vcon()->vcon_get_attr(attr), 4, 0, 0);
        }
      case L4_VCON_READ_OP:
        break;
 
      default:
        return l4_msgtag(-L4_ENOSYS, 0, 0, 0);
      }
 
    unsigned const max_size = L4_VCON_READ_SIZE;
    char buf[max_size];
 
    unsigned size = cxx::min<unsigned>(m->mr[0] >> 16, max_size);
 
    // Hmm, could we avoid the double copy here?
    l4_umword_t v = this_vcon()->vcon_read(buf, size);
    unsigned bytes = v & L4_VCON_READ_SIZE_MASK;
 
    if (bytes <= size)
      v |= L4_VCON_READ_STAT_DONE;
    else
      // In case of size == max_size, the returned bytes value is greater than
      // the buffer.
      bytes = size;
 
    m->mr[0] = v;
    __builtin_memcpy(&m->mr[1], buf, bytes);
 
    return l4_msgtag(0, l4_bytes_to_mwords(bytes) + 1, 0, 0);
  }
 
  unsigned vcon_read(char *buf, unsigned size) noexcept;
  void vcon_write(const char *buf, unsigned size) noexcept;
  int vcon_set_attr(l4_vcon_attr_t const *) noexcept
  { return -L4_EOK; }
  int vcon_get_attr(l4_vcon_attr_t *attr) noexcept
  {
    attr->l_flags = attr->o_flags = attr->i_flags = 0;
    return -L4_EOK;
  }
 
private:
  SVR const *this_vcon() const { return static_cast<SVR const *>(this); }
  SVR *this_vcon() { return static_cast<SVR *>(this); }
};
 
}}