【文件系统学习】+小燕+开发板跑fs将romfs中tar文件解压到fa...

发布于 2018-07-29 00:54:30 浏览：2297 订阅该版

```#define STK_UNTAR_SIZE        1024
#define TASK_UNTAR_PRIORITY   1

#define UNTAR_TARGET_DIR          "sdcard/untar"
#define TAR_FILE                  "/untar_test.tar"
#define TAR_FILE_BLOCK_SIZE       512
#define TAR_FILE_TYPE_FILE        '0'
// linkflag是'5'表示这个文件是目录，那么这个文件块将没有数据
#define TAR_FILE_TYPE_DIR         '5'

/*
 * standard archive format - standard tar - ustar
 */
#define  recordsize  512
#define  namsiz      100
#define  tunmlen      32
#define  tgnmlen      32

typedef struct {
	char    name[namsiz];
	char    mode[8];
	char    uid[8];
	char    gid[8];
	char    size[12];
	char    mtime[12];
	char    chksum[8];
	char    linkflag;
	char    linkname[namsiz];
	char    magic[8];
	char    uname[tunmlen];
	char    gname[tgnmlen];
	char    devmajor[8];
	char    devminor[8];
}_tar_header;

// 这个方法是从学习营其他人那看到的，非常好，借用
typedef union {
    rt_uint8_t buffer[TAR_FILE_BLOCK_SIZE];
    _tar_header header;
}_tar_block;

// romfs
extern const struct romfs_dirent romfs_root;
// 解压任务
rt_thread_t s_untar_thread = RT_NULL;

//八进制转十进制
int convertOctalToDecimal(int octalNumber)
{
    int decimalNumber = 0, i = 0;

while (octalNumber != 0) {
        decimalNumber += (octalNumber%10) * pow(8, i);
        ++i;
        octalNumber /= 10;
    }

return decimalNumber;
}

// 解析tar文件
void untar_function(int argc, char **argv)
{
    // tar文件句柄
	struct dfs_fd tar_fd;
	// tar中的文件的句柄
	struct dfs_fd fd;
	// tar文件信息
	struct stat tar_file_stat;
	// 用来解析读取数据是否是文件头
	_tar_block *pblock;
	int size, block_num = 0, i, j, k;
	char target_dir[128] = {0}, file_dir[128] = {0};
	rt_uint8_t block_data[TAR_FILE_BLOCK_SIZE] = {0};
	int file_total_size;

// 打开文件
 if (dfs_file_open(&tar_fd, TAR_FILE, O_RDONLY)) {
		rt_kprintf("open failed. ");
		return;
	}
 // 获取tar文件信息
	if (dfs_file_stat(TAR_FILE, &tar_file_stat)) {
		dfs_file_close(&tar_fd);
		return;
	}
 rt_kprintf("untar_test.tar file size = %d block %d ", 
		tar_file_stat.st_size, tar_file_stat.st_size / 512);
 rt_kprintf("tar_header size %d ", sizeof(_tar_header));
 block_num = tar_file_stat.st_size / 512;

for (i = 0; i <= block_num; i++) {
 // 读文件
 size = dfs_file_read(&tar_fd, block_data, TAR_FILE_BLOCK_SIZE);
 pblock = (_tar_block *)block_data;
 // 文件头
 if ((size == TAR_FILE_BLOCK_SIZE) && !(strcmp(pblock->header.magic, "ustar")))
 {
 if (pblock->header.linkflag == TAR_FILE_TYPE_DIR)// 目录
 {
 // 将读到的目录创建出来
 rt_memset(target_dir, 0, sizeof(target_dir));
 strcat(target_dir, UNTAR_TARGET_DIR);
 strcat(target_dir, pblock->header.name);
 if (mkdir(target_dir, 0x777) < 0) {
 rt_kprintf("creat dir err. ");
 return;
 }
 }
 else if (pblock->header.linkflag == TAR_FILE_TYPE_FILE)// 文件
 {
 // 先创建文件目录
 rt_memset(file_dir, 0, sizeof(file_dir));
 strcat(file_dir, UNTAR_TARGET_DIR);
 strcat(file_dir, pblock->header.name);
 for (j = (rt_strlen(file_dir) - 1); j>= 0; j--)
 if (file_dir[j] == '/')
 file_dir[j + 1] = 0; //截断
 mkdir(file_dir, 0x777); 	 
		
 // 创建文件
 rt_memset(file_dir, 0, sizeof(file_dir));
 strcat(file_dir, UNTAR_TARGET_DIR);
 strcat(file_dir, pblock->header.name);
 if (dfs_file_open(&fd, file_dir, O_RDWR | O_CREAT | O_APPEND))
 rt_kprintf("open %s failed ", pblock->header.name);
		
 file_total_size = convertOctalToDecimal(atoi(pblock->header.size));
 j = 0;
 }
 }
 // 文件内容
 else
 {
 for (k = 0; k < TAR_FILE_BLOCK_SIZE; k++)
 {
 dfs_file_write(&fd, &block_data[k], 1);
 j++;
 //读取数据结束
 if (j >= file_total_size)
 dfs_file_close(&fd);
 }
		
 }
 }
	dfs_file_close(&tar_fd);
}
MSH_CMD_EXPORT(untar_function, untar file to sdcard);

// user main
int main(void)
{
 // 挂载romfs
 if (dfs_mount(RT_NULL, "/", "rom", 0, &(romfs_root)) == 0) {
 rt_kprintf("ROM System initialized! ");
 } else {
 rt_kprintf("ROM System init failed! ");
 }
	// 挂载fatfs到sd卡
 if (dfs_mount("sd0", "/sdcard", "elm", 0, 0) == 0)
 {
 rt_kprintf("file system initialization done! ");
 } else {
 rt_kprintf("file system initialization failed! ");
 }
 return 0;
}
```

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