/src/os/linux/ftk_mmap_linux.c

  1/*
  2 * File: ftk_mmap_linux.c
  3 * Author:  Li XianJing <xianjimli@hotmail.com>
  4 * Brief:   linux mmap implemention.
  5 *
  6 * Copyright (c) 2009 - 2010  Li XianJing <xianjimli@hotmail.com>
  7 *
  8 * Licensed under the Academic Free License version 2.1
  9 *
 10 * This program is free software; you can redistribute it and/or modify
 11 * it under the terms of the GNU General Public License as published by
 12 * the Free Software Foundation; either version 2 of the License, or
 13 * (at your option) any later version.
 14 *
 15 * This program is distributed in the hope that it will be useful,
 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 18 * GNU General Public License for more details.
 19 *
 20 * You should have received a copy of the GNU General Public License
 21 * along with this program; if not, write to the Free Software
 22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 23 */
 24
 25/*
 26 * History:
 27 * ================================================================
 28 * 2009-11-20 Li XianJing <xianjimli@hotmail.com> created
 29 *
 30 */
 31
 32#include "ftk_log.h"
 33#include "ftk_mmap.h"
 34#include "ftk_allocator.h"
 35#include <sys/mman.h>
 36
 37struct _FtkMmap
 38{
 39	int fd;
 40	void* data;
 41	size_t length;
 42};
 43
 44int      ftk_mmap_exist(const char* filename)
 45{
 46	struct stat st = {0};
 47	return_val_if_fail(filename != NULL, 0);
 48
 49	return stat(filename, &st) == 0;
 50}
 51
 52FtkMmap* ftk_mmap_create(const char* filename, size_t offset, size_t size)
 53{
 54	FtkMmap* thiz = NULL;
 55	struct stat st = {0};
 56	return_val_if_fail(filename != NULL, NULL);
 57	if(stat(filename, &st) != 0)
 58	{
 59		return NULL;
 60	}
 61	return_val_if_fail(offset < st.st_size, NULL);
 62
 63	size = (offset + size) <= st.st_size ? size : st.st_size - offset;
 64
 65	thiz = FTK_ZALLOC(sizeof(FtkMmap));
 66	return_val_if_fail(thiz != NULL, NULL);
 67
 68	thiz->fd = open(filename, O_RDONLY);
 69	if(thiz->fd > 0)
 70	{
 71		thiz->length = size;
 72		thiz->data = mmap(NULL, size, PROT_READ, MAP_PRIVATE, thiz->fd, offset);
 73	}
 74
 75	if(thiz->data == NULL || thiz->data == MAP_FAILED)
 76	{
 77		close(thiz->fd);
 78		FTK_ZFREE(thiz, sizeof(*thiz));
 79		ftk_logd("%s mmap %s failed.\n", __func__, filename);
 80	}
 81
 82	return thiz;
 83}
 84
 85void*    ftk_mmap_data(FtkMmap* thiz)
 86{
 87	return_val_if_fail(thiz != NULL, NULL);
 88
 89	return thiz->data;
 90}
 91
 92size_t   ftk_mmap_length(FtkMmap* thiz)
 93{
 94	return_val_if_fail(thiz != NULL, 0);
 95
 96	return thiz->length;
 97}
 98
 99void     ftk_mmap_destroy(FtkMmap* thiz)
100{
101	if(thiz != NULL)
102	{
103		close(thiz->fd);
104		munmap(thiz->data, thiz->length);
105
106		FTK_ZFREE(thiz, sizeof(*thiz));
107	}
108
109	return;
110}
111
112