目录与文件属性——《Unix/Linux编程实践教程》读书笔记

1、ls产生一个文件名的列表，它大致是这样工作的：

open directory
+-> read entry        - end of dir? -+
|__ display file info                |
    close directory   <--------------+

3、man 3 readdir

#include <sys/types.h>
#include <dirent.h>

DIR *opendir(const char *dir_name);
struct dirent *readdir(DIR *dir_name);
int readdir_r(DIR *dir_ptr, struct dirent *entry,
    struct dirent **result);
long telldir(DIR *dir_ptr);
void seekdir(DIR *dir_ptr, long location);
void rewinddir(DIR *dir_ptr);
int closedir(DIR *dir_ptr);

main()
    opendir
    while (readdir)
        print d_name
    closedir

man 2 stat

#include <sys/stat.h>

int res = stat(const char *path, struct stat *buf);
    /* return 0 for success, -1 for error */

struct stat {
    dev_t     st_dev;     /* ID of device containing file */
    ino_t     st_ino;     /* inode number */
    mode_t    st_mode;    /* protection */
    nlink_t   st_nlink;   /* number of hard links */
    uid_t     st_uid;     /* user ID of owner */
    gid_t     st_gid;     /* group ID of owner */
    dev_t     st_rdev;    /* device ID (if special file) */
    off_t     st_size;    /* total size, in bytes */
    blksize_t st_blksize; /* blocksize for filesystem I/O */
    blkcnt_t  st_blocks;  /* number of 512B blocks allocated */
    time_t    st_atime;   /* time of last access */
    time_t    st_mtime;   /* time of last modification */
    time_t    st_ctime;   /* time of last status change */
};

7、SUID 位告诉内核，运行这个程序的时候认为是由文件所有者在运行这个程序；SGID位告诉内核，运行这个程序的时候认为文件所属的组在运行这个程序；sticky位对于文件，在早期用于交换（swap）技术，对于目录而言被设计用来存放临时文件，如/tmp。

ls -l sample
-rwsr-sr-t   1   root root 2345    Jul 24 00:45    sample

#include <sys/types.h>
#include <sys/stat.h>

int res = chmod(const char *path, mod_t mode);
int res = chmod(int fd, mode_t mode);
    /* On success, 0 is returned. On error, -1 is returned
       and errno is set appropriately */

#include <unistd.h>

int chown(const char *path, uid_t owner, gid_t group);
int fchown(int fd, uid_t owner, gid_t group);
int lchown(const char *path, uid_t owner, gid_t group);
    /* On success, 0 is returned. On error, -1 is returned
       and errno is set appropriately */

man utime

man 2 rename

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