I am trying to write a small C program that emulates the unix command
ls -l
. To do so, I am using the stat(2)
syscall and have ran into a small hiccup writing the permissions. I have a mode_t
variable which holds the file permissions from st_mode
, and it wouldn't be hard to parse that value into s string representation, but I was just wondering if there is a better way to be doing it than that.
example from google
#include <unistd.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
int main(int argc, char **argv)
{
if(argc != 2)
return 1;
struct stat fileStat;
if(stat(argv[1], &fileStat) < 0)
return 1;
printf("Information for %s\n", argv[1]);
printf("---------------------------\n");
printf("File Size: \t\t%d bytes\n", fileStat.st_size);
printf("Number of Links: \t%d\n", fileStat.st_nlink);
printf("File inode: \t\t%d\n", fileStat.st_ino);
printf("File Permissions: \t");
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("\n\n");
printf("The file %s a symbolic link\n", (S_ISLNK(fileStat.st_mode)) ? "is" : "is not");
return 0;
}
result:
Information for 2.c --------------------------- File Size: 1223 bytes Number of Links: 1 File inode: 39977236 File Permissions: -rw-r--r-- The file is not a symbolic link