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