cygserver_shm.h

cygwin, 著名的在win32下模拟unix操作系统的东东

/* cygserver_shm.h: Single unix specification IPC interface for Cygwin.

   Copyright 2002 Red Hat, Inc.

   Written by Conrad Scott <[e-mail]>.
   Based on code by Robert Collins <[e-mail]>.

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#ifndef __CYGSERVER_SHM_H__
#define __CYGSERVER_SHM_H__

#include <sys/types.h>
#include <cygwin/shm.h>

#include <assert.h>
#include <limits.h>

#include "cygserver_ipc.h"

#include "cygwin/cygserver.h"

/*---------------------------------------------------------------------------*
 * Values for the shminfo entries.
 *
 * Nb. The values are segregated between two enums so that the `small'
 * values aren't promoted to `unsigned long' equivalents.
 *---------------------------------------------------------------------------*/

enum
  {
    SHMMAX = ULONG_MAX,
    SHMSEG = ULONG_MAX,
    SHMALL = ULONG_MAX
  };

enum
  {
    SHMMIN = 1,
    SHMMNI = IPCMNI		// Must be <= IPCMNI.
  };

/*---------------------------------------------------------------------------*
 * class client_request_shm
 *---------------------------------------------------------------------------*/

#ifndef __INSIDE_CYGWIN__
class transport_layer_base;
class process_cache;
#endif

class client_request_shm : public client_request
{
  friend class client_request;

public:
  enum shmop_t
    {
      SHMOP_shmat,
      SHMOP_shmctl,
      SHMOP_shmdt,
      SHMOP_shmget
    };

#ifdef __INSIDE_CYGWIN__
  client_request_shm (int shmid, int shmflg); // shmat
  client_request_shm (int shmid, int cmd, const struct shmid_ds *); // shmctl
  client_request_shm (int shmid); // shmdt
  client_request_shm (key_t, size_t, int shmflg); // shmget
#endif

  // Accessors for out parameters.

  int shmid () const
  {
    assert (!error_code ());
    return _parameters.out.shmid;
  }

  HANDLE hFileMap () const
  {
    assert (!error_code ());
    return _parameters.out.hFileMap;
  }

  const struct shmid_ds & ds () const
  {
    assert (!error_code ());
    return _parameters.out.ds;
  }

  const struct shminfo & shminfo () const
  {
    assert (!error_code ());
    return _parameters.out.shminfo;
  }

  const struct shm_info & shm_info () const
  {
    assert (!error_code ());
    return _parameters.out.shm_info;
  }

private:
  union
  {
    struct
    {
      shmop_t shmop;
      key_t key;
      size_t size;
      int shmflg;
      int shmid;
      int cmd;
      pid_t cygpid;
      DWORD winpid;
      uid_t uid;
      gid_t gid;
      struct shmid_ds ds;
    } in;

    struct {
      int shmid;
      union
      {
	HANDLE hFileMap;
	struct shmid_ds ds;
	struct shminfo shminfo;
	struct shm_info shm_info;
      };
    } out;
  } _parameters;

#ifndef __INSIDE_CYGWIN__
  client_request_shm ();
#endif

#ifndef __INSIDE_CYGWIN__
  virtual void serve (transport_layer_base *, process_cache *);
#endif
};

#endif /* __CYGSERVER_SHM_H__ */