• 20145209《信息安全系统设计基础》第11周学习总结


    学号20145209《信息安全系统设计基础》第11周学习总结

    教材学习内容总结

    教材学习内容总结
    代码运行情况
    1、cp1.c

    include <stdio.h> //标准输入输出头文件
    include <stdlib.h> //标准库头文件
    include <unistd.h> //unix类系统定义符号常量的头文件
    include <fcntl.h> //定义了一组基于C的非缓冲的文件操作函数,可用于文件和设备(及socket等)的I/O操作
    define BUFFERSIZE 4096 //缓冲区大小
    define COPYMODE 0644 // 新文件的访问权限位
    void oops(char , char ); //错误处理函数

    int main(int argc, char argv[])
    {
    int in_fd, out_fd, n_chars;
    char buf[BUFFERSIZE]; //定义缓冲区
    if (argc != 3) //当输入参数不足时
    {
    fprintf(stderr, "usage: %s source destination ", argv);
    exit(1);
    }

    if ((in_fd = open(argv[1], O_RDONLY)) == -1) /打开文件失败
    oops("Cannot open ", argv[1]);

    if ((out_fd = creat(argv[2], COPYMODE)) == -1) //创建新文件失败
    oops("Cannot creat", argv[2]);

    while ((n_chars = read(in_fd, buf, BUFFERSIZE)) > 0) //缓冲区不空时,开始写文件
    if (write(out_fd, buf, n_chars) != n_chars) //写文件出错
    oops("Write error to ", argv[2]);
    if (n_chars == -1) //从文件中读数据出错
    oops("Read error from ", argv[1]);

    if (close(in_fd) == -1 || close(out_fd) == -1) //关闭输入文件出错或关闭输出文件出错
    oops("Error closing files", "");
    }

    void oops(char s1, char s2) //错误处理
    {
    fprintf(stderr, "Error: %s ", s1);
    perror(s2);
    exit(1);
    }
    首先,进入week10文件夹,用vim编辑器编辑cp1.c的代码并编译:

    再次查看scncp1.c中的内容,发现和cp1.c中的内容完全一致:

    说明此代码的功能是:复制文件或目录

    2、echostate.c

    include <stdio.h>
    include <stdlib.h>
    include <termios.h>
    int main()
    {
    struct termios info;
    int rv;

    rv = tcgetattr( 0, &info );     /* read values from driver      */
    
    if ( rv == -1 ){
            perror( "tcgetattr");
            exit(1);
    }
    if ( info.c_lflag & ECHO )
            printf(" echo is on , since its bit is 1
    ");
    else
            printf(" echo is OFF, since its bit is 0
    ");
    
    return 0;
    

    }

    功能:查看在命令行中输入命令时是否可见,可见返回1,否则返回0

    3、fileinfo.c

    include <stdio.h>
    include
    include
    void show_stat_info(char , struct stat );
    //显示文件属性函数
    int main(int argc, char *argv[])
    {
    struct stat info;

    if (argc>1) //运行时有参数
    {

    if( stat(argv[1], &info) != -1 )    //显示文件状态
    {
        show_stat_info( argv[1], &info );
        return 0;
    }
    else
        perror(argv[1]);  //错误处理
    

    }
    return 1;
    }
    void show_stat_info(char fname, struct stat buf)
    {
    printf(" mode: %o ", buf->st_mode);
    printf(" links: %d ", buf->st_nlink);
    printf(" user: %d ", buf->st_uid);
    printf(" group: %d ", buf->st_gid);
    printf(" size: %d ", (int)buf->st_size);
    printf("modtime: %d ", (int)buf->st_mtime);
    printf(" name: %s ", fname );
    }

    功能:查看文件信息

    4、filesize.c

    include <stdio.h>
    include
    int main()
    {
    struct stat infobuf;

    if ( stat( "/etc/passwd", &infobuf) == -1 )
    //查看文件属性函数
    perror("/etc/passwd"); //错误处理
    else
    printf(" The size of /etc/passwd is %d ", infobuf.st_size );
    }

    功能:查看文件大小

    5、ls1.c

    include <stdio.h>
    include
    include <dirent.h>
    void do_ls(char []);

    int main(int argc, char argv[])
    {
    if ( argc == 1 ) //没有参数是,显示 当前万人当
    do_ls( "." );
    else
    while ( --argc ){
    printf("%s: ", ++argv ); //显示参数
    do_ls( *argv );
    }

    return 0;
    }

    void do_ls( char dirname[] )
    {
    DIR dir_ptr; //DIR表示目录类型
    struct dirent direntp; //目录结构体

    if ( ( dir_ptr = opendir( dirname ) ) == NULL )
    fprintf(stderr,"ls1: cannot open %s ", dirname);
    else
    {
    while ( ( direntp = readdir( dir_ptr ) ) != NULL )
    printf("%s ", direntp->d_name );
    closedir(dir_ptr);
    }
    }

    功能:显示当前目录下的所有文件

    6、ls2.c

    include <stdio.h>
    include <string.h>
    include
    include <dirent.h>
    include
    void do_ls(char[]); //显示指定目录下的文件
    void dostat(char ); //显示文件属性
    void show_file_info( char , struct stat ); //显示文件读取详细信息
    void mode_to_letters( int , char [] ); //显示文件读取权限信息
    char uid_to_name( uid_t );
    char *gid_to_name( gid_t );

    int main(int argc, char argv[])
    {
    if ( argc == 1 )
    do_ls( "." );
    else
    while ( --argc ){
    printf("%s: ", ++argv );
    do_ls( *argv );
    }

    return 0;
    }

    void do_ls( char dirname[] )
    {
    DIR dir_ptr;
    struct dirent direntp;

    if ( ( dir_ptr = opendir( dirname ) ) == NULL )
    fprintf(stderr,"ls1: cannot open %s ", dirname);
    else
    {
    while ( ( direntp = readdir( dir_ptr ) ) != NULL )
    dostat( direntp->d_name );
    closedir(dir_ptr);
    }
    }

    void dostat( char *filename )
    {
    struct stat info;

    if ( stat(filename, &info) == -1 )
    perror( filename );
    else
    show_file_info( filename, &info );
    }

    void show_file_info( char filename, struct stat info_p )
    {
    char uid_to_name(), ctime(), gid_to_name(), filemode();
    void mode_to_letters();
    char modestr[11];

    mode_to_letters( info_p->st_mode, modestr );

    printf( "%s" , modestr );
    printf( "%4d " , (int) info_p->st_nlink);
    printf( "%-8s " , uid_to_name(info_p->st_uid) );
    printf( "%-8s " , gid_to_name(info_p->st_gid) );
    printf( "%8ld " , (long)info_p->st_size);
    printf( "%.12s ", 4+ctime(&info_p->st_mtime));
    printf( "%s " , filename );
    }

    void mode_to_letters( int mode, char str[] )
    {
    strcpy( str, "----------" );

    if ( S_ISDIR(mode) ) str[0] = 'd';
    if ( S_ISCHR(mode) ) str[0] = 'c';
    if ( S_ISBLK(mode) ) str[0] = 'b';

    if ( mode & S_IRUSR ) str[1] = 'r';
    if ( mode & S_IWUSR ) str[2] = 'w';
    if ( mode & S_IXUSR ) str[3] = 'x';

    if ( mode & S_IRGRP ) str[4] = 'r';
    if ( mode & S_IWGRP ) str[5] = 'w';
    if ( mode & S_IXGRP ) str[6] = 'x';

    if ( mode & S_IROTH ) str[7] = 'r';
    if ( mode & S_IWOTH ) str[8] = 'w';
    if ( mode & S_IXOTH ) str[9] = 'x';
    }

    include <pwd.h> //定义口令结构体
    char uid_to_name( uid_t uid )
    {
    struct passwd getpwuid(), *pw_ptr;
    static char numstr[10];

    if ( ( pw_ptr = getpwuid( uid ) ) == NULL ){
    sprintf(numstr,"%d", uid);
    return numstr;
    }
    else
    return pw_ptr->pw_name ;
    }

    include <grp.h> //包含组结构的定义
    char gid_to_name( gid_t gid )
    {
    struct group getgrgid(), *grp_ptr;
    static char numstr[10];

    if ( ( grp_ptr = getgrgid(gid) ) == NULL ){
    sprintf(numstr,"%d", gid);
    return numstr;
    }
    else
    return grp_ptr->gr_name; //返回组名
    }

    功能:显示指定目录下的文件详细信息

    7、setcho.c

    include <stdio.h>
    include <stdlib.h>
    include <termios.h> //串口配置中,终端的工作模式,是一个结构体
    define oops(s,x) { perror(s); exit(x); }
    //用于错误处理的宏

    int main(int argc, char *argv[])
    {
    struct termios info;

    if ( argc == 1 ) 
    exit(0);
    
    if ( tcgetattr(0,&info) == -1 )          /* 获取文件属性   */
        oops("tcgettattr", 1);
    
    if ( argv[1][0] == 'y' )
            info.c_lflag |= ECHO ;          /* 设置打开标志位    */
    else
            info.c_lflag &= ~ECHO ;         /* 设置关闭标志位   */
    
    if ( tcsetattr(0,TCSANOW,&info) == -1 ) /* 设置文件属性    */
           oops("tcsetattr",2);
    
    return 0;
    

    }

    功能:设置echo的状态

    8、spwd.c

    include <stdio.h>
    include <stdlib.h>
    include <string.h>
    include
    include
    include <dirent.h>
    ino_t get_inode(char ); // 获取i-node节点号
    void printpathto(ino_t); // 打印当前目录路径
    void inum_to_name(ino_t , char , int ); //根据i-node节点找到对应文件名

    int main()
    {
    printpathto( get_inode( "." ) );
    putchar(' ');
    return 0;
    }

    void printpathto( ino_t this_inode )
    {
    ino_t my_inode ;
    char its_name[BUFSIZ];

    if ( get_inode("..") != this_inode )
    {
    chdir( ".." );

    inum_to_name(this_inode,its_name,BUFSIZ);
    
    my_inode = get_inode( "." );        
    printpathto( my_inode );        
    printf("/%s", its_name );       
    

    }
    }

    void inum_to_name(ino_t inode_to_find , char namebuf, int buflen)
    {
    DIR dir_ptr;
    struct dirent *direntp;

    dir_ptr = opendir( "." );
    if ( dir_ptr == NULL ){
    perror( "." );
    exit(1);
    }

    while ( ( direntp = readdir( dir_ptr ) ) != NULL )
    if ( direntp->d_ino == inode_to_find )
    {
    strncpy( namebuf, direntp->d_name, buflen);
    namebuf[buflen-1] = '';
    closedir( dir_ptr );
    return;
    }
    fprintf(stderr, "error looking for inum %d ", (int) inode_to_find);
    exit(1);
    }

    ino_t get_inode( char *fname )
    {
    struct stat info;

    if ( stat( fname , &info ) == -1 ){
    fprintf(stderr, "Cannot stat ");
    perror(fname);
    exit(1);
    }
    return info.st_ino; //返回i-node节点号
    }

    功能:显示当前目录路径

    9、testioctl.c

    include <stdio.h>
    include <stdlib.h>
    include <unistd.h>
    include
    int main()
    {
    struct winsize size;
    if( isatty(STDOUT_FILENO) == 0) //判断一个文件描述符是否指向一个终端
    exit(1);
    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &size) < 0) //控制驱动器
    {
    perror("ioctl TIOCGWINSZ error");
    exit(1);
    }

    printf("%d rows %d columns ", size.ws_row, size.ws_col);
    return 0;
    }

    功能:查看窗体大小信息

    9、who1.c

    include <stdio.h>
    include <stdlib.h>
    include <utmp.h> // 定义用户信息结构体
    include <fcntl.h>
    include <unistd.h> //对 POSIX 操作系统 API 的访问功能的头文件
    define SHOWHOST
    int show_info( struct utmp *utbufp )
    {
    printf("%-8.8s", utbufp->ut_name);
    printf(" ");
    printf("%-8.8s", utbufp->ut_line);
    printf(" ");
    printf("%10ld", utbufp->ut_time);
    printf(" ");

    ifdef SHOWHOST
    printf("(%s)", utbufp->ut_host);
    endif
    printf(" ");

    return 0;
    }
    int main()
    {
    struct utmp current_record;
    int utmpfd;
    int reclen = sizeof(current_record);

    if ( (utmpfd = open(UTMP_FILE, O_RDONLY)) == -1 ){
    perror( UTMP_FILE );
    exit(1);
    }
    while ( read(utmpfd, &current_record, reclen) == reclen )
    show_info(&current_record);
    close(utmpfd);
    return 0;

    学习进度条

    代码行数(新增/累积) 博客量(新增/累积) 学习时间(新增/累积) 重要成长
    目标 5000行 30篇 400小时
    第一周 200/200 2/2 20/20
    第二周 300/500 2/4 18/38
    第三周 500/1000 3/7 22/60
    第四周 300/1300 2/9 30/90

    参考资料

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  • 原文地址:https://www.cnblogs.com/liuyiyang/p/6107389.html
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