ipc_stream

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// vi:set ft=cpp: -*- Mode: C++ -*-
/*
 * (c) 2008-2009 Adam Lackorzynski <adam@os.inf.tu-dresden.de>,
 *               Alexander Warg <warg@os.inf.tu-dresden.de>,
 *               Torsten Frenzel <frenzel@os.inf.tu-dresden.de>
 *     economic rights: Technische Universität Dresden (Germany)
 *
 * This file is part of TUD:OS and distributed under the terms of the
 * GNU General Public License 2.
 * Please see the COPYING-GPL-2 file for details.
 *
 * As a special exception, you may use this file as part of a free software
 * library without restriction.  Specifically, if other files instantiate
 * templates or use macros or inline functions from this file, or you compile
 * this file and link it with other files to produce an executable, this
 * file does not by itself cause the resulting executable to be covered by
 * the GNU General Public License.  This exception does not however
 * invalidate any other reasons why the executable file might be covered by
 * the GNU General Public License.
 */
#pragma once
 
#include <l4/sys/ipc.h>
#include <l4/sys/capability>
#include <l4/sys/cxx/ipc_types>
#include <l4/sys/cxx/ipc_varg>
#include <l4/cxx/type_traits>
#include <l4/cxx/minmax>
 
namespace L4 {
namespace Ipc {
 
class Ostream;
class Istream;
 
namespace Internal {
template< typename T >
class Buf_cp_out
{
public:
  Buf_cp_out(T const *v, unsigned long size) : _v(v), _s(size) {}
 
  unsigned long size() const { return _s; }
 
  T const *buf() const { return _v; }
 
private:
  friend class Ostream;
  T const *_v;
  unsigned long _s;
};
}
 
template< typename T >
Internal::Buf_cp_out<T> buf_cp_out(T const *v, unsigned long size)
{ return Internal::Buf_cp_out<T>(v, size); }
 
 
namespace Internal {
template< typename T >
class Buf_cp_in
{
public:
  Buf_cp_in(T *v, unsigned long &size) : _v(v), _s(&size) {}
 
  unsigned long &size() const { return *_s; }
  T *buf() const { return _v; }
 
private:
  friend class Istream;
  T *_v;
  unsigned long *_s;
};
}
 
template< typename T >
Internal::Buf_cp_in<T> buf_cp_in(T *v, unsigned long &size)
{ return Internal::Buf_cp_in<T>(v, size); }
 
template< typename T >
class Str_cp_in
{
public:
  Str_cp_in(T *v, unsigned long &size) : _v(v), _s(&size) {}
 
  unsigned long &size() const { return *_s; }
  T *buf() const { return _v; }
 
private:
  friend class Istream;
  T *_v;
  unsigned long *_s;
};
 
template< typename T >
Str_cp_in<T> str_cp_in(T *v, unsigned long &size)
{ return Str_cp_in<T>(v, size); }
 
template< typename T >
class Msg_ptr
{
private:
  T **_p;
public:
  explicit Msg_ptr(T *&p) : _p(&p) {}
  void set(T *p) const { *_p = p; }
};
 
template< typename T >
Msg_ptr<T> msg_ptr(T *&p)
{ return Msg_ptr<T>(p); }
 
 
namespace Internal {
template< typename T >
class Buf_in
{
public:
  Buf_in(T *&v, unsigned long &size) : _v(&v), _s(&size) {}
 
  void set_size(unsigned long s) const { *_s = s; }
  T *&buf() const { return *_v; }
 
private:
  friend class Istream;
  T **_v;
  unsigned long *_s;
};
}
 
template< typename T >
Internal::Buf_in<T> buf_in(T *&v, unsigned long &size)
{ return Internal::Buf_in<T>(v, size); }
 
namespace Utcb_stream_check
{
  static bool check_utcb_data_offset(unsigned sz)
  { return sz > sizeof(l4_umword_t) * L4_UTCB_GENERIC_DATA_SIZE; }
}
 
 
class Istream
{
public:
  Istream(l4_utcb_t *utcb)
  : _tag(), _utcb(utcb),
    _current_msg(reinterpret_cast<char*>(l4_utcb_mr_u(utcb)->mr)),
    _pos(0), _current_buf(0)
  {}
 
  void reset()
  {
    _pos = 0;
    _current_buf = 0;
    _current_msg = reinterpret_cast<char*>(l4_utcb_mr_u(_utcb)->mr);
  }
 
  template< typename T >
  bool has_more(unsigned long count = 1)
  {
    auto const max_bytes = L4_UTCB_GENERIC_DATA_SIZE * sizeof(l4_umword_t);
    unsigned apos = cxx::Type_traits<T>::align(_pos);
    return (count <= max_bytes / sizeof(T))
           && (apos + (sizeof(T) * count)
               <= _tag.words() * sizeof(l4_umword_t));
  }
 
 
  template< typename T >
  unsigned long get(T *buf, unsigned long elems)
  {
    if (L4_UNLIKELY(!has_more<T>(elems)))
      return 0;
 
    unsigned long size = elems * sizeof(T);
    _pos = cxx::Type_traits<T>::align(_pos);
 
    __builtin_memcpy(buf, _current_msg + _pos, size);
    _pos += size;
    return elems;
  }
 
 
  template< typename T >
  void skip(unsigned long elems)
  {
    if (L4_UNLIKELY(!has_more<T>(elems)))
      return;
 
    unsigned long size = elems * sizeof(T);
    _pos = cxx::Type_traits<T>::align(_pos);
    _pos += size;
  }
 
  template< typename T >
  unsigned long get(Msg_ptr<T> const &buf, unsigned long elems = 1)
  {
    if (L4_UNLIKELY(!has_more<T>(elems)))
      return 0;
 
    unsigned long size = elems * sizeof(T);
    _pos = cxx::Type_traits<T>::align(_pos);
 
    buf.set(reinterpret_cast<T*>(_current_msg + _pos));
    _pos += size;
    return elems;
  }
 
 
  template< typename T >
  bool get(T &v)
  {
    if (L4_UNLIKELY(!has_more<T>()))
      {
        v = T();
        return false;
      }
 
    _pos = cxx::Type_traits<T>::align(_pos);
    v = *(reinterpret_cast<T*>(_current_msg + _pos));
    _pos += sizeof(T);
    return true;
  }
 
 
  bool get(Ipc::Varg *va)
  {
    Ipc::Varg::Tag t;
    if (!has_more<Ipc::Varg::Tag>())
      {
        va->tag(0);
  return 0;
      }
    get(t);
    va->tag(t);
    char const *d;
    get(msg_ptr(d), va->length());
    va->data(d);
 
    return 1;
  }
 
  l4_msgtag_t tag() const { return _tag; }
 
 
  l4_msgtag_t &tag() { return _tag; }
 
 
  inline bool put(Rcv_fpage const &);
 
  inline bool put(Small_buf const &);
 
 
 
  inline l4_msgtag_t wait(l4_umword_t *src)
  { return wait(src, L4_IPC_NEVER); }
 
  inline l4_msgtag_t wait(l4_umword_t *src, l4_timeout_t timeout);
 
  inline l4_msgtag_t receive(l4_cap_idx_t src)
  { return receive(src, L4_IPC_NEVER); }
  inline l4_msgtag_t receive(l4_cap_idx_t src, l4_timeout_t timeout);
 
 
  inline l4_utcb_t *utcb() const { return _utcb; }
 
protected:
  l4_msgtag_t _tag;
  l4_utcb_t *_utcb;
  char *_current_msg;
  unsigned _pos;
  unsigned char _current_buf;
};
 
class Istream_copy : public Istream
{
private:
  l4_msg_regs_t _mrs;
 
public:
  Istream_copy(Istream const &o) : Istream(o), _mrs(*l4_utcb_mr_u(o.utcb()))
  {
    // do some reverse mr to utcb trickery
    _utcb = reinterpret_cast<l4_utcb_t *>
      (reinterpret_cast<l4_addr_t>(&_mrs)
       - reinterpret_cast<l4_addr_t>(l4_utcb_mr_u(nullptr)));
    _current_msg = reinterpret_cast<char*>(l4_utcb_mr_u(_utcb)->mr);
  }
 
};
 
class Ostream
{
public:
  Ostream(l4_utcb_t *utcb)
  : _tag(), _utcb(utcb),
    _current_msg(reinterpret_cast<char *>(l4_utcb_mr_u(_utcb)->mr)),
    _pos(0), _current_item(0)
  {}
 
  void reset()
  {
    _pos = 0;
    _current_item = 0;
    _current_msg = reinterpret_cast<char*>(l4_utcb_mr_u(_utcb)->mr);
  }
 
 
  template< typename T >
  bool put(T *buf, unsigned long size)
  {
    size *= sizeof(T);
    _pos = cxx::Type_traits<T>::align(_pos);
    if (Utcb_stream_check::check_utcb_data_offset(_pos + size))
      return false;
 
    __builtin_memcpy(_current_msg + _pos, buf, size);
    _pos += size;
    return true;
  }
 
  template< typename T >
  bool put(T const &v)
  {
    _pos = cxx::Type_traits<T>::align(_pos);
    if (Utcb_stream_check::check_utcb_data_offset(_pos + sizeof(T)))
      return false;
 
    *(reinterpret_cast<T*>(_current_msg + _pos)) = v;
    _pos += sizeof(T);
    return true;
  }
 
  int put(Varg const &va)
  {
    put(va.tag());
    put(va.data(), va.length());
 
    return 0;
  }
 
  template< typename T >
  int put(Varg_t<T> const &va)
  { return put(static_cast<Varg const &>(va)); }
 
  l4_msgtag_t tag() const { return _tag; }
 
  l4_msgtag_t &tag() { return _tag; }
 
 
  inline bool put_snd_item(Snd_fpage const &);
 
 
 
  inline l4_msgtag_t send(l4_cap_idx_t dst, long proto = 0, unsigned flags = 0);
 
 
  inline l4_utcb_t *utcb() const { return _utcb; }
#if 0
  unsigned long tell() const
  {
    unsigned w = l4_bytes_to_mwords(_pos) - _current_item * 2;
    _tag = l4_msgtag(0, w, _current_item, 0);
  }
#endif
public:
  l4_msgtag_t prepare_ipc(long proto = 0, unsigned flags = 0)
  {
    unsigned w = l4_bytes_to_mwords(_pos) - _current_item * 2;
    return l4_msgtag(proto, w, _current_item, flags);
  }
 
  // XXX: this is a hack for <l4/sys/cxx/ipc_server> adaption
  void set_ipc_params(l4_msgtag_t tag)
  {
    _pos = (tag.words() + tag.items() * 2) * sizeof(l4_umword_t);
    _current_item = tag.items();
  }
protected:
  l4_msgtag_t _tag;
  l4_utcb_t *_utcb;
  char *_current_msg;
  unsigned _pos;
  unsigned char _current_item;
};
 
 
class Iostream : public Istream, public Ostream
{
public:
 
  explicit Iostream(l4_utcb_t *utcb)
  : Istream(utcb), Ostream(utcb)
  {}
 
  // disambiguate those functions
  l4_msgtag_t tag() const { return Istream::tag(); }
  l4_msgtag_t &tag() { return Istream::tag(); }
  l4_utcb_t *utcb() const { return Istream::utcb(); }
 
  void reset()
  {
    Istream::reset();
    Ostream::reset();
  }
 
 
 
  using Istream::get;
  using Istream::put;
  using Ostream::put;
 
 
 
  inline l4_msgtag_t call(l4_cap_idx_t dst, l4_timeout_t timeout, long proto = 0);
  inline l4_msgtag_t call(l4_cap_idx_t dst, long proto = 0);
 
  inline l4_msgtag_t reply_and_wait(l4_umword_t *src_dst, long proto = 0)
  { return reply_and_wait(src_dst, L4_IPC_SEND_TIMEOUT_0, proto); }
 
  inline l4_msgtag_t send_and_wait(l4_cap_idx_t dest, l4_umword_t *src,
                                   long proto = 0)
  { return send_and_wait(dest, src, L4_IPC_SEND_TIMEOUT_0, proto); }
 
  inline l4_msgtag_t reply_and_wait(l4_umword_t *src_dst,
                                    l4_timeout_t timeout, long proto = 0);
  inline l4_msgtag_t send_and_wait(l4_cap_idx_t dest, l4_umword_t *src,
                                   l4_timeout_t timeout, long proto = 0);
  inline l4_msgtag_t reply(l4_timeout_t timeout, long proto = 0);
  inline l4_msgtag_t reply(long proto = 0)
  { return reply(L4_IPC_SEND_TIMEOUT_0, proto); }
 
};
 
 
inline bool
Ostream::put_snd_item(Snd_fpage const &v)
{
  typedef Snd_fpage T;
  _pos = cxx::Type_traits<Snd_fpage>::align(_pos);
  if (Utcb_stream_check::check_utcb_data_offset(_pos + sizeof(T)))
    return false;
 
  *(reinterpret_cast<T*>(_current_msg + _pos)) = v;
  _pos += sizeof(T);
  ++_current_item;
  return true;
}
 
 
inline bool
Istream::put(Rcv_fpage const &item)
{
  unsigned words = item.is_compound() ? 3 : 2;
  if (_current_buf >= L4_UTCB_GENERIC_BUFFERS_SIZE - words - 1)
    return false;
 
  l4_utcb_br_u(_utcb)->bdr &= ~L4_BDR_OFFSET_MASK;
 
  l4_umword_t *buf
    = reinterpret_cast<l4_umword_t *>(&l4_utcb_br_u(_utcb)->br[_current_buf]);
  *buf++ = item.base_x();
  *buf++ = item.data();
  if (item.is_compound())
    *buf++ = item.rcv_task();
  _current_buf += words;
  return true;
}
 
 
inline bool
Istream::put(Small_buf const &item)
{
  if (_current_buf >= L4_UTCB_GENERIC_BUFFERS_SIZE - 2)
    return false;
 
  l4_utcb_br_u(_utcb)->bdr &= ~L4_BDR_OFFSET_MASK;
 
  reinterpret_cast<Small_buf&>(l4_utcb_br_u(_utcb)->br[_current_buf]) = item;
  _current_buf += 1;
  return true;
}
 
 
inline l4_msgtag_t
Ostream::send(l4_cap_idx_t dst, long proto, unsigned flags)
{
  l4_msgtag_t tag = prepare_ipc(proto, L4_MSGTAG_FLAGS & flags);
  return l4_ipc_send(dst, _utcb, tag, L4_IPC_NEVER);
}
 
inline l4_msgtag_t
Iostream::call(l4_cap_idx_t dst, l4_timeout_t timeout, long label)
{
  l4_msgtag_t tag = prepare_ipc(label);
  tag = l4_ipc_call(dst, Ostream::_utcb, tag, timeout);
  Istream::tag() = tag;
  Istream::_pos = 0;
  return tag;
}
 
inline l4_msgtag_t
Iostream::call(l4_cap_idx_t dst, long label)
{ return call(dst, L4_IPC_NEVER, label); }
 
 
inline l4_msgtag_t
Iostream::reply_and_wait(l4_umword_t *src_dst, l4_timeout_t timeout, long proto)
{
  l4_msgtag_t tag = prepare_ipc(proto);
  tag = l4_ipc_reply_and_wait(Ostream::_utcb, tag, src_dst, timeout);
  Istream::tag() = tag;
  Istream::_pos = 0;
  return tag;
}
 
 
inline l4_msgtag_t
Iostream::send_and_wait(l4_cap_idx_t dest, l4_umword_t *src,
                        l4_timeout_t timeout, long proto)
{
  l4_msgtag_t tag = prepare_ipc(proto);
  tag = l4_ipc_send_and_wait(dest, Ostream::_utcb, tag, src, timeout);
  Istream::tag() = tag;
  Istream::_pos = 0;
  return tag;
}
 
inline l4_msgtag_t
Iostream::reply(l4_timeout_t timeout, long proto)
{
  l4_msgtag_t tag = prepare_ipc(proto);
  tag = l4_ipc_send(L4_INVALID_CAP | L4_SYSF_REPLY, Ostream::_utcb, tag, timeout);
  Istream::tag() = tag;
  Istream::_pos = 0;
  return tag;
}
 
inline l4_msgtag_t
Istream::wait(l4_umword_t *src, l4_timeout_t timeout)
{
  l4_msgtag_t res;
  res = l4_ipc_wait(_utcb, src, timeout);
  tag() = res;
  _pos = 0;
  return res;
}
 
 
inline l4_msgtag_t
Istream::receive(l4_cap_idx_t src, l4_timeout_t timeout)
{
  l4_msgtag_t res;
  res = l4_ipc_receive(src, _utcb, timeout);
  tag() = res;
  _pos = 0;
  return res;
}
 
} // namespace Ipc
} // namespace L4
 
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, bool &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, int &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, long int &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, long long int &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, unsigned int &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, unsigned long int &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, unsigned long long int &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, short int &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, unsigned short int &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, char &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, unsigned char &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, signed char &v) { s.get(v); return s; }
inline L4::Ipc::Istream &operator << (L4::Ipc::Istream &s, L4::Ipc::Rcv_fpage const &v) { s.put(v); return s; }
inline L4::Ipc::Istream &operator << (L4::Ipc::Istream &s, L4::Ipc::Small_buf const &v) { s.put(v); return s; }
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, L4::Ipc::Snd_fpage &v)
{
  l4_umword_t b, d;
  s >> b >> d;
  v = L4::Ipc::Snd_fpage(b, d);
  return s;
}
inline L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, L4::Ipc::Varg &v)
{ s.get(&v); return s; }
 
 
inline
L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s, l4_msgtag_t &v)
{
  v = s.tag();
  return s;
}
 
template< typename T >
inline
L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s,
                               L4::Ipc::Internal::Buf_in<T> const &v)
{
  unsigned long si;
  if (s.get(si) && s.has_more<T>(si))
    v.set_size(s.get(L4::Ipc::Msg_ptr<T>(v.buf()), si));
  else
    v.set_size(0);
  return s;
}
 
template< typename T >
inline
L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s,
                               L4::Ipc::Msg_ptr<T> const &v)
{
  s.get(v);
  return s;
}
 
template< typename T >
inline
L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s,
                               L4::Ipc::Internal::Buf_cp_in<T> const &v)
{
  unsigned long sz;
  s.get(sz);
  v.size() = s.get(v.buf(), cxx::min(v.size(), sz));
  return s;
}
 
template< typename T >
inline
L4::Ipc::Istream &operator >> (L4::Ipc::Istream &s,
                               L4::Ipc::Str_cp_in<T> const &v)
{
  unsigned long sz;
  s.get(sz);
  unsigned long rsz = s.get(v.buf(), cxx::min(v.size(), sz));
  if (rsz < v.size() && v.buf()[rsz - 1])
    ++rsz; // add the zero termination behind the received data
 
  if (rsz != 0)
    v.buf()[rsz - 1] = 0;
 
  v.size() = rsz;
  return s;
}
 
 
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, bool v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, int v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, long int v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, long long int v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, unsigned int v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, unsigned long int v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, unsigned long long int v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, short int v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, unsigned short int v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, char v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, unsigned char v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, signed char v) { s.put(v); return s; }
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, L4::Ipc::Snd_fpage const &v) { s.put_snd_item(v); return s; }
template< typename T >
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, L4::Cap<T> const &v)
{ s << L4::Ipc::Snd_fpage(v.fpage()); return s; }
 
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, L4::Ipc::Varg const &v)
{ s.put(v); return s; }
template< typename T >
inline L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, L4::Ipc::Varg_t<T> const &v)
{ s.put(v); return s; }
 
inline
L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, l4_msgtag_t const &v)
{
  s.tag() = v;
  return s;
}
 
template< typename T >
inline
L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s,
                               L4::Ipc::Internal::Buf_cp_out<T> const &v)
{
  s.put(v.size());
  s.put(v.buf(), v.size());
  return s;
}
 
inline
L4::Ipc::Ostream &operator << (L4::Ipc::Ostream &s, char const *v)
{
  unsigned long l = __builtin_strlen(v) + 1;
  s.put(l);
  s.put(v, l);
  return s;
}
 
namespace L4 { namespace Ipc {
template< typename T >
inline
T read(Istream &s) { T t; s >> t; return t; }
 
} // namespace Ipc
} // namespace L4