003_2022_23_file_info.c

#include <dirent.h>
#include <fcntl.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

void displayList(struct stat *, const char *);

int main(int argc, const char **argv)
{
    if (argc < 2) {
        printf("%s <filename>\n", argv[0]);
        exit(EXIT_FAILURE);
    }
    struct stat    filestat;
    DIR *          dirp = NULL;
    struct dirent *direntp;
    stat(argv[1], &filestat);

    if (S_ISDIR((&filestat)->st_mode)) {
        // chdir(argv[1]);
        dirp = opendir(argv[1]);
        while ((direntp = readdir(dirp)) != NULL) {
            displayList(&filestat, direntp->d_name);
        }
    }
    else {
        displayList(&filestat, argv[1]);
    }
    return EXIT_SUCCESS;
}

void displayList(struct stat *filestat, const char *fileName)
{
    struct passwd *pwd;
    struct group * grp;
    char           f_created_time[50];
    grp = getgrgid(filestat->st_gid);
    pwd = getpwuid(filestat->st_uid);
    struct tm c_time;
    c_time = *localtime(&filestat->st_ctime);
    strftime(f_created_time, sizeof(f_created_time), "%b %2d %R", &c_time);

    printf((S_ISDIR(filestat->st_mode)) ? "d" : "-");
    printf((filestat->st_mode & S_IRUSR) ? "r" : "-");
    printf((filestat->st_mode & S_IWUSR) ? "w" : "-");
    printf((filestat->st_mode & S_IXUSR) ? "x" : "-");
    printf((filestat->st_mode & S_IRGRP) ? "r" : "-");
    printf((filestat->st_mode & S_IWGRP) ? "w" : "-");
    printf((filestat->st_mode & S_IXGRP) ? "x" : "-");
    printf((filestat->st_mode & S_IROTH) ? "r" : "-");
    printf((filestat->st_mode & S_IWOTH) ? "w" : "-");
    printf((filestat->st_mode & S_IXOTH) ? "x" : "-");
    printf(" ");

    printf("%2lu %14.32s %14.32s % ld %12.14s %s\n", filestat->st_nlink, pwd->pw_name, grp->gr_name,
           filestat->st_size, f_created_time, fileName);
}