/*

   +----------------------------------------------------------------------+

   | Zend OPcache                                                         |

   +----------------------------------------------------------------------+

   | Copyright (c) The PHP Group                                          |

   +----------------------------------------------------------------------+

   | This source file is subject to version 3.01 of the PHP license,      |

   | that is bundled with this package in the file LICENSE, and is        |

   | available through the world-wide-web at the following url:           |

   | https://www.php.net/license/3_01.txt                                 |

   | If you did not receive a copy of the PHP license and are unable to   |

   | obtain it through the world-wide-web, please send a note to          |

   | license@php.net so we can mail you a copy immediately.               |

   +----------------------------------------------------------------------+

   | Authors: Andi Gutmans <andi@php.net>                                 |

   |          Zeev Suraski <zeev@php.net>                                 |

   |          Stanislav Malyshev <stas@zend.com>                          |

   |          Dmitry Stogov <dmitry@php.net>                              |

   +----------------------------------------------------------------------+

*/

#include "zend_shared_alloc.h"

#ifdef USE_SHM

#if defined(__FreeBSD__)

# include <machine/param.h>

#endif

#include <sys/types.h>

#include <sys/shm.h>

#include <sys/ipc.h>

#include <signal.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <errno.h>

#include <sys/stat.h>

#include <fcntl.h>

#ifndef MIN

# define MIN(x, y) ((x) > (y)? (y) : (x))

#endif

#define SEG_ALLOC_SIZE_MAX 32*1024*1024

#define SEG_ALLOC_SIZE_MIN 2*1024*1024

typedef struct  {

    zend_shared_segment common;

    int shm_id;

} zend_shared_segment_shm;

static int create_segments(size_t requested_size, zend_shared_segment_shm ***shared_segments_p, int *shared_segments_count, const char **error_in)

{

  int i;

  size_t allocate_size = 0, remaining_bytes = requested_size, seg_allocate_size;

  int first_segment_id = -1;

  key_t first_segment_key = -1;

  struct shmid_ds sds;

  int shmget_flags;

  zend_shared_segment_shm *shared_segments;

  seg_allocate_size = SEG_ALLOC_SIZE_MAX;

  /* determine segment size we _really_ need:

   * no more than to include requested_size

   */

  while (requested_size * 2 <= seg_allocate_size && seg_allocate_size > SEG_ALLOC_SIZE_MIN) {

    seg_allocate_size >>= 1;

  }

  shmget_flags = IPC_CREAT|SHM_R|SHM_W|IPC_EXCL;

  /* try allocating this much, if not - try shrinking */

  while (seg_allocate_size >= SEG_ALLOC_SIZE_MIN) {

    allocate_size = MIN(requested_size, seg_allocate_size);

    first_segment_id = shmget(first_segment_key, allocate_size, shmget_flags);

    if (first_segment_id != -1) {

      break;

    }

    seg_allocate_size >>= 1; /* shrink the allocated block */

  }

  if (first_segment_id == -1) {

    *error_in = "shmget";

    return ALLOC_FAILURE;

  }

  *shared_segments_count = ((requested_size - 1) / seg_allocate_size) + 1;

  *shared_segments_p = (zend_shared_segment_shm **) calloc(1, (*shared_segments_count) * sizeof(zend_shared_segment_shm) + sizeof(void *) * (*shared_segments_count));

  if (!*shared_segments_p) {

    *error_in = "calloc";

    return ALLOC_FAILURE;

  }

  shared_segments = (zend_shared_segment_shm *)((char *)(*shared_segments_p) + sizeof(void *) * (*shared_segments_count));

  for (i = 0; i < *shared_segments_count; i++) {

    (*shared_segments_p)[i] = shared_segments + i;

  }

  remaining_bytes = requested_size;

  for (i = 0; i < *shared_segments_count; i++) {

    allocate_size = MIN(remaining_bytes, seg_allocate_size);

    if (i != 0) {

      shared_segments[i].shm_id = shmget(IPC_PRIVATE, allocate_size, shmget_flags);

    } else {

      shared_segments[i].shm_id = first_segment_id;

    }

    if (shared_segments[i].shm_id == -1) {

      return ALLOC_FAILURE;

    }

    shared_segments[i].common.p = shmat(shared_segments[i].shm_id, NULL, 0);

    if (shared_segments[i].common.p == (void *)-1) {

      *error_in = "shmat";

      shmctl(shared_segments[i].shm_id, IPC_RMID, &sds);

      return ALLOC_FAILURE;

    }

    shmctl(shared_segments[i].shm_id, IPC_RMID, &sds);

    shared_segments[i].common.pos = 0;

    shared_segments[i].common.size = allocate_size;

    remaining_bytes -= allocate_size;

  }

  return ALLOC_SUCCESS;

}

static int detach_segment(zend_shared_segment_shm *shared_segment)

{

  shmdt(shared_segment->common.p);

  return 0;

}

static size_t segment_type_size(void)

{

  return sizeof(zend_shared_segment_shm);

}

const zend_shared_memory_handlers zend_alloc_shm_handlers = {

  (create_segments_t)create_segments,

  (detach_segment_t)detach_segment,

  segment_type_size

};

#endif /* USE_SHM */