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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2017/11/30 Bernard The first version.
* 2024/03/29 TroyMitchelle Add all function comments
*/
#include <stdint.h>
#include <stdio.h>
#include <rtthread.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/errno.h>
#include "sys/mman.h"
/**
* @brief Maps a region of memory into the calling process's address space.
* @param addr Desired starting address of the mapping.
* @param length Length of the mapping.
* @param prot Protection of the mapped memory region.
* @param flags Type of the mapped memory region.
* @param fd File descriptor of the file to be mapped.
* @param offset Offset within the file to start the mapping.
* @return Upon success, returns a pointer to the mapped region; otherwise, MAP_FAILED is returned.
*/
void *mmap(void *addr, size_t length, int prot, int flags,
int fd, off_t offset)
{
uint8_t *mem;
if (addr)
{
mem = addr;
}
else mem = (uint8_t *)malloc(length);
if (mem)
{
off_t cur;
size_t read_bytes;
cur = lseek(fd, 0, SEEK_SET);
lseek(fd, offset, SEEK_SET);
read_bytes = read(fd, mem, length);
if (read_bytes != length)
{
if (addr == RT_NULL)
{
/* read failed */
free(mem);
mem = RT_NULL;
}
}
lseek(fd, cur, SEEK_SET);
return mem;
}
errno = ENOMEM;
return MAP_FAILED;
}
/**
* @brief Unmaps a mapped region of memory.
* @param addr Starting address of the mapping to be unmapped.
* @param length Length of the mapping.
* @return Upon success, returns 0; otherwise, -1 is returned.
*/
int munmap(void *addr, size_t length)
{
if (addr)
{
free(addr);
return 0;
}
return -1;
}
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