學習筆記，小白可以相互學習，大佬看到能告訴咱理解不對的地方就好了。
函數
1.stat
獲取文件/目錄屬性信息
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
int stat(const char *path, struct stat *buf); //主要掌握這一個，函數返回一個與此命名有關的信息結構
int fstat(int fd, struct stat *buf);
int lstat(const char *path, struct stat *buf);
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 file system 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 */
};
struct passwd *uid = getpwuid(b.st_uid); //獲得用戶名
struct group *gid = getgrgid(b.st_gid);//獲得所屬組名
struct tm *t = localtime(&b.st_ctime);//獲取時間
printf("%2d月,%2d日,%2d點,%2d分,%2d秒 ",t->tm_mon,t->tm_mday,t->tm_hour,t->tm_min,t->tm_sec);
/**************自己寫的實現ls -l功能*******************************/
#include<stdio.h>
#include<fcntl.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<unistd.h>
#include<dirent.h>
#include<pwd.h>
#include<grp.h>
#include<time.h>
int main()
{
DIR *f = opendir(".");
struct dirent *r;
struct stat b;
while( r = readdir(f) )
{
if( 0 > stat(r->d_name,&b))
{
perror("stat");
return -1;
}
struct passwd *uid = getpwuid(b.st_uid); //獲得用戶名
struct group *gid = getgrgid(b.st_gid);//獲得所屬組名
printf("userID:%s ",uid->pw_name);
printf("groupID:%s ",gid->gr_name);
//******************文件類型**************
switch(b.st_mode & S_IFMT)//文件類型的位遮罩S_TFMT
{
case S_IFREG:
printf("-");
break;
case S_IFDIR:
printf("d");
break;
case S_IFCHR:
printf("c");
break;
case S_IFBLK:
printf("b");
break;
case S_IFIFO:
printf("p");
break;
case S_IFLNK:
printf("c");
break;
case S_IFSOCK:
printf("s");
break;
}
//***********************文件的權限**************
(b.st_mode & S_IRUSR?printf("r"):printf("-"));
(b.st_mode & S_IWUSR?printf("w"):printf("-"));
(b.st_mode & S_IXUSR?printf("x"):printf("-"));
(b.st_mode & S_IRGRP?printf("r"):printf("-"));
(b.st_mode & S_IWGRP?printf("w"):printf("-"));
(b.st_mode & S_IXGRP?printf("x"):printf("-"));
(b.st_mode & S_IROTH?printf("r"):printf("-"));
(b.st_mode & S_IWOTH?printf("w"):printf("-"));
(b.st_mode & S_IXOTH?printf("x "):printf("- "));
//**********文件大小************************
printf("%5ld ",b.st_size);
//************時間*******************************
struct tm *t = localtime(&b.st_ctime);
printf("%2d月,%2d日,%2d點,%2d分,%2d秒 ",t->tm_mon,t->tm_mday,t->tm_hour,t->tm_min,t->tm_sec);
//************文件名字***************
printf("%s",r->d_name);
printf("\n");
}
closedir(f);
return 0;
}
/*******************標準點的********************************/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
void getfiletype(mode_t m, char *type)
{
if (S_ISREG(m))
*type = '-';
else if (S_ISDIR(m))
*type = 'd';
else if (S_ISCHR(m))
*type = 'c';
else if (S_ISBLK(m))
*type = 'b';
else if (S_ISFIFO(m))
*type = 'p';
else if (S_ISLNK(m))
*type = 'l';
else if (S_ISSOCK(m))
*type = 's';
}
void getfilemode(mode_t m, char *mode)
{
if (m & S_IRUSR)
mode[0] = 'r';
if (m & S_IWUSR)
mode[1] = 'w';
if (m & S_IXUSR)
mode[2] = 'x';
if (m & S_IRGRP)
mode[3] = 'r';
if (m & S_IWGRP)
mode[4] = 'w';
if (m & S_IXGRP)
mode[5] = 'x';
if (m & S_IROTH)
mode[6] = 'r';
if (m & S_IWOTH)
mode[7] = 'w';
if (m & S_IXOTH)
mode[8] = 'x';
}
void getfileusrname(uid_t uid, char *usrname)
{
struct passwd *pw = getpwuid(uid);
strcpy(usrname, pw->pw_name);
}
void getfilegrpname(gid_t gid, char *grpname)
{
struct group *grp = getgrgid(gid);
strcpy(grpname, grp->gr_name);
}
void getfiletime(time_t ctime, char *filetime)
{
struct tm *tm = localtime(&ctime);
sprintf(filetime, "%2d月 %2d %2d:%2d", tm->tm_mon+1, tm->tm_mday, \
tm->tm_hour, tm->tm_min);
}
int main()
{
DIR *dirp = opendir(".");
struct dirent *file;
struct stat buf;
while (file = readdir(dirp)) {
if (0 > stat(file->d_name, &buf)) {
perror("stat");
break;
}
char type;
getfiletype(buf.st_mode, &type);
char mode[9] = {0};
memset(mode, '-', sizeof(mode));
getfilemode(buf.st_mode, mode);
char usrname[10];
getfileusrname(buf.st_uid, usrname);
char grpname[10];
getfilegrpname(buf.st_gid, grpname);
char filetime[20];
getfiletime(buf.st_ctime, filetime);
fprintf(stdout, "%c%9s %2d %10s %10s %6ld %15s %s\n", type, mode, buf.st_nlink, usrname, grpname, buf.st_size, filetime, file->d_name);
}
return 0;
}2.opendir
打開目錄
#include <sys/types.h>
#include <dirent.h>
DIR *opendir(const char *name);
成功返回DIR*類型的目錄流，失敗返回NULL
3.readdir
讀取目錄
#include <dirent.h>
struct dirent *readdir(DIR *dirp);
成功返回下個目錄進入點，失敗或者到達目錄文件尾返回NULL
struct dirent {
ino_t d_ino; /* inode number */
off_t d_off; /* offset to the next dirent */
unsigned short d_reclen; /* length of this record */
unsigned char d_type; /* type of file; not supported
by all file system types */
char d_name[256]; /* filename */
};
DIR *f = opendir(".");//打開當前目錄
struct dirent *r;
struct stat b;
while(r = readdir(f)) //讀取目錄
{printf("%s",r->d_name);}//目錄下的成員名
4.closedir
關閉目錄
#include <sys/types.h>
#include <dirent.h>
int closedir(DIR *dirp);
關閉成功返回0，失敗返回-1，並設置errno
