Hust OS Lab

Because the lab5 is a little more complex, so I show some details about it aspecting to how it works and the ideas behind it.

How it works

Adding and Deleting

The picture as show below, after launch the program, you can use ls to show files and directories, mkdir to create directories, touch to show create files and so on.

Integrating Vim

Vim is essential for IO, but implementing a toy vim is distraction.

How to build it

Manage free inodes

Using linked list and root node keeps the next free inode num.

Manage free blocks

Integrate Vim

Here is the core code. execvp and wait are the only two key function.

    printf("start vim !\n");
    char * args[] = {"vim", VIM_BUF_PATH, NULL};
    int status;
    if(!fork()){
        execvp("vim", args);
    }
    wait(&status);
    printf("back to the main process\n");


    buf = fopen(VIM_BUF_PATH, "rb");
    fseek(buf, 0, SEEK_END);
    long fsize = ftell(buf);
    fseek(buf, 0, SEEK_SET);
    contend = (char *)malloc(fsize + 1);
    fread(contend, fsize, 1, buf);
    fclose(buf);
    contend[fsize] = '\0';

    clear(f);

    if(DEBUG_APP) printf("从buf.txt 中间 向 该文件 写入数据长度为%lu\n", fsize + 1);
    write_file(contend, sizeof(char), fsize + 1, f);
    save_inode(f);