/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 */
/******************************************************************************\
*
* Implement of abstract I/O interface for MMAP.
*
\******************************************************************************/

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>

#include <errno.h>
#include <fcntl.h>              /* IO operations */
#include <sys/stat.h>
#include <sys/mman.h>
#include <assert.h>

#include "ior.h"
#include "aiori.h"
#include "aiori-POSIX.h"
#include "iordef.h"
#include "utilities.h"

/**************************** P R O T O T Y P E S *****************************/
static aiori_fd_t *MMAP_Create(char *, int flags, aiori_mod_opt_t *);
static aiori_fd_t *MMAP_Open(char *, int flags, aiori_mod_opt_t *);
static IOR_offset_t MMAP_Xfer(int, aiori_fd_t *, IOR_size_t *,
                               IOR_offset_t, IOR_offset_t, aiori_mod_opt_t *);
static void MMAP_Close(aiori_fd_t *, aiori_mod_opt_t *);
static void MMAP_Fsync(aiori_fd_t *, aiori_mod_opt_t *);
static option_help * MMAP_options(aiori_mod_opt_t ** init_backend_options, aiori_mod_opt_t * init_values);
static void MMAP_xfer_hints(aiori_xfer_hint_t * params);
static int MMAP_check_params(aiori_mod_opt_t * options);
/************************** D E C L A R A T I O N S ***************************/

ior_aiori_t mmap_aiori = {
        .name = "MMAP",
        .create = MMAP_Create,
        .open = MMAP_Open,
        .xfer = MMAP_Xfer,
        .close = MMAP_Close,
        .delete = POSIX_Delete,
        .xfer_hints = MMAP_xfer_hints,
        .get_version = aiori_get_version,
        .fsync = MMAP_Fsync,
        .get_file_size = POSIX_GetFileSize,
        .get_options = MMAP_options,
        .check_params = MMAP_check_params
};

/***************************** F U N C T I O N S ******************************/
typedef struct{
  int direct_io_ignored; /* this option is ignored */
  void* mmap_ptr; /* for internal usage */

  int madv_dont_need;
  int madv_pattern;
} mmap_options_t;

static option_help * MMAP_options(aiori_mod_opt_t ** init_backend_options, aiori_mod_opt_t * init_values){
  mmap_options_t * o = malloc(sizeof(mmap_options_t));

  if (init_values != NULL){
    memcpy(o, init_values, sizeof(mmap_options_t));
  }else{
    memset(o, 0, sizeof(mmap_options_t));
  }

  *init_backend_options = (aiori_mod_opt_t*) o;

  option_help h [] = {
    {0, "mmap.madv_dont_need", "Use advise don't need", OPTION_FLAG, 'd', & o->madv_dont_need},
    {0, "mmap.madv_pattern", "Use advise to indicate the pattern random/sequential", OPTION_FLAG, 'd', & o->madv_pattern},
    LAST_OPTION
  };
  option_help * help = malloc(sizeof(h));
  memcpy(help, h, sizeof(h));
  return help;
}

static aiori_xfer_hint_t * hints = NULL;

static void MMAP_xfer_hints(aiori_xfer_hint_t * params){
  hints = params;
  POSIX_xfer_hints(params);
}

static int MMAP_check_params(aiori_mod_opt_t * options){
  if (hints->fsyncPerWrite && (hints->transferSize & (sysconf(_SC_PAGESIZE) - 1)))
    ERR("transfer size must be aligned with PAGESIZE for MMAP with fsyncPerWrite");
  return 0;
}

static void ior_mmap_file(int *file, int mflags, void *param)
{
        int flags = PROT_READ;
        IOR_offset_t size = hints->expectedAggFileSize;

        if (mflags & IOR_WRONLY || mflags & IOR_RDWR)
                flags |= PROT_WRITE;
        mmap_options_t *o = (mmap_options_t*) param;

        o->mmap_ptr = mmap(NULL, size, flags, MAP_SHARED,
                               *file, 0);
        if (o->mmap_ptr == MAP_FAILED)
                ERR("mmap() failed");

        if (hints->randomOffset)
                flags = POSIX_MADV_RANDOM;
        else
                flags = POSIX_MADV_SEQUENTIAL;

        if(o->madv_pattern){
          if (posix_madvise(o->mmap_ptr, size, flags) != 0)
          ERR("madvise() failed");
        }

        if (o->madv_dont_need){
          if (posix_madvise(o->mmap_ptr, size, POSIX_MADV_DONTNEED) != 0)
          ERR("madvise() failed");
        }

        return;
}

/*
 * Create and open a file through the POSIX interface, then setup mmap.
 */
static aiori_fd_t *MMAP_Create(char *testFileName, int flags, aiori_mod_opt_t * param)
{
        int *fd;

        fd = (int*) POSIX_Create(testFileName, flags, param);
        if (ftruncate(*fd, hints->expectedAggFileSize) != 0)
                ERR("ftruncate() failed");
        ior_mmap_file(fd, flags, param);
        return ((aiori_fd_t *)fd);
}

/*
 * Open a file through the POSIX interface and setup mmap.
 */
static aiori_fd_t *MMAP_Open(char *testFileName, int flags, aiori_mod_opt_t * param)
{
        int *fd;
        fd = (int*) POSIX_Open(testFileName, flags, param);
        ior_mmap_file(fd, flags, param);
        return ((aiori_fd_t *)fd);
}

/*
 * Write or read access to file using mmap
 */
static IOR_offset_t MMAP_Xfer(int access, aiori_fd_t *file, IOR_size_t * buffer,
                               IOR_offset_t length, IOR_offset_t offset, aiori_mod_opt_t * param)
{
        mmap_options_t *o = (mmap_options_t*) param;
        if (access == WRITE) {
                memcpy(o->mmap_ptr + offset, buffer, length);
        } else {
                memcpy(buffer, o->mmap_ptr + offset, length);
        }

        if (hints->fsyncPerWrite == TRUE) {
                if (msync(o->mmap_ptr + offset, length, MS_SYNC) != 0)
                        ERR("msync() failed");
                if (posix_madvise(o->mmap_ptr + offset, length,
                                  POSIX_MADV_DONTNEED) != 0)
                        ERR("madvise() failed");
        }
        return (length);
}

/*
 * Perform msync().
 */
static void MMAP_Fsync(aiori_fd_t *fd, aiori_mod_opt_t * param)
{
        mmap_options_t *o = (mmap_options_t*) param;
        if (msync(o->mmap_ptr, hints->expectedAggFileSize, MS_SYNC) != 0)
                EWARN("msync() failed");
}

/*
 * Close a file through the POSIX interface, after tear down the mmap.
 */
static void MMAP_Close(aiori_fd_t *fd, aiori_mod_opt_t * param)
{
        mmap_options_t *o = (mmap_options_t*) param;
        if (munmap(o->mmap_ptr, hints->expectedAggFileSize) != 0)
                ERR("munmap failed");
        o->mmap_ptr = NULL;
        POSIX_Close(fd, param);
}