/* Copyright (C) 2014 Stony Brook University
   This file is part of Graphene Library OS.

   Graphene Library OS is free software: you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public License
   as published by the Free Software Foundation, either version 3 of the
   License, or (at your option) any later version.

   Graphene Library OS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/*
 * pal_host.h
 *
 * This file contains definition of PAL host ABI.
 */

#ifndef PAL_HOST_H
#define PAL_HOST_H

#ifndef IN_PAL
# error "cannot be included outside PAL"
#endif

#include <atomic.h>

/* Simpler mutex design: a single variable that tracks whether the
 * mutex is locked (just waste a 64 bit word for now).  State is 1 (locked) or
 * 0 (unlocked).
 * Keep a count of how many threads are waiting on the mutex.
 * If DEBUG_MUTEX is defined,
 * mutex_handle will record the owner of mutex locking. */
typedef struct mutex_handle {
    volatile int64_t locked;
    struct atomic_int nwaiters;
#ifdef DEBUG_MUTEX
    int owner;
#endif
} PAL_LOCK;

/* Initializer of Mutexes */
#define MUTEX_HANDLE_INIT    { .locked = 0, .nwaiters.counter = 0 }
#define INIT_MUTEX_HANDLE(m)  do { (m)->locked = 0; atomic_set(&(m)->nwaiters, 0); } while (0)

#define LOCK_INIT MUTEX_HANDLE_INIT
#define INIT_LOCK(lock) INIT_MUTEX_HANDLE(lock)

/* Locking and unlocking of Mutexes */
int _DkMutexLock(struct mutex_handle* mut);
int _DkMutexLockTimeout(struct mutex_handle* mut, int64_t timeout_us);
int _DkMutexUnlock(struct mutex_handle* mut);

typedef struct {
    PAL_HDR hdr;
} PAL_RESERVED_HDR;

typedef struct pal_handle
{
    /* TSAI: Here we define the internal types of PAL_HANDLE
     * in PAL design, user has not to access the content inside the
     * handle, also there is no need to allocate the internal
     * handles, so we hide the type name of these handles on purpose.
     */
    PAL_HDR hdr;

    union {
        struct {
            PAL_IDX fds[MAX_FDS];
        } generic;

        struct {
            PAL_IDX fd;
            PAL_STR realpath;
            /*
             * map_start is to request this file should be mapped to this
             * address. When fork is emulated, the address is already
             * determined by parent process.
             */
            PAL_PTR map_start;
        } file;

        struct {
            PAL_IDX fd;
            PAL_NUM pipeid;
            PAL_BOL nonblocking;
        } pipe;

        struct {
            PAL_IDX fds[MAX_FDS];
            PAL_BOL nonblocking;
        } pipeprv;

        struct {
            PAL_IDX fd;
            /* TODO: add other flags in future, if needed (e.g., semaphore) */
            PAL_BOL nonblocking;
        } eventfd;

        struct {
            PAL_IDX fd_in, fd_out;
            PAL_IDX dev_type;
            PAL_BOL destroy;
            PAL_STR realpath;
        } dev;

        struct {
            PAL_IDX fd;
            PAL_STR realpath;
            PAL_PTR buf;
            PAL_PTR ptr;
            PAL_PTR end;
            PAL_BOL endofstream;
        } dir;

        struct {
            PAL_IDX fd;
            PAL_PTR bind;
            PAL_PTR conn;
            PAL_BOL nonblocking;
            PAL_BOL reuseaddr;
            PAL_NUM linger;
            PAL_NUM receivebuf;
            PAL_NUM sendbuf;
            PAL_NUM receivetimeout;
            PAL_NUM sendtimeout;
            PAL_BOL tcp_cork;
            PAL_BOL tcp_keepalive;
            PAL_BOL tcp_nodelay;
        } sock;

        struct {
            PAL_IDX stream;
            PAL_IDX cargo;
            PAL_IDX pid;
            PAL_BOL nonblocking;
        } process;

        struct {
            PAL_IDX tid;
            PAL_PTR stack;
        } thread;

        struct {
            struct mutex_handle mut;
        } mutex;

        struct {
            struct atomic_int signaled;
            struct atomic_int nwaiters;
            PAL_BOL isnotification;
        } event;
    };
} * PAL_HANDLE;

#define RFD(n)          (1 << (MAX_FDS*0 + (n)))
#define WFD(n)          (1 << (MAX_FDS*1 + (n)))
#define ERROR(n)        (1 << (MAX_FDS*2 + (n)))

#define HANDLE_TYPE(handle)  ((handle)->hdr.type)

extern void __check_pending_event (void);

#define LEAVE_PAL_CALL() do { __check_pending_event(); } while (0)

#define LEAVE_PAL_CALL_RETURN(retval) \
    do { __check_pending_event(); return (retval); } while (0)

#endif /* PAL_HOST_H */