[SOLVED] C Programm of "ls -aln" but not working good

Issue

I've done a C program that does what the ls -aln command does, but I have a problem.

I expect this results :

drwxr-xr-x@  6 seven  staff   192 19 fév 18:58 .
drwxr-xr-x@  4 seven  staff   128  6 fév 00:37 ..
drwxr-xr-x@  7 seven  staff   224 17 fév 15:00 .idea
-rw-r--r--@  1 seven  staff   104  5 fév 17:37 CMakeLists.txt
drwxr-xr-x@ 11 seven  staff   352 19 fév 18:58 cmake-build-debug
-rw-r--r--@  1 seven  staff  2144 19 fév 18:58 main.c

but instead I'm having this:

d-----rwxr-xr-x  11  352     seven   staff   .
d-----rwxr-xr-x  6   192     seven   staff   ..
d-----rwxr-xr-x  6   192     seven   staff   cmake-build-debug
d-----rwxr-xr-x  6   192     seven   staff   CMakeLists.txt
d-----rwxr-xr-x  6   192     seven   staff   main.c
d-----rwxr-xr-x  6   192     seven   staff   .idea

Basically my number of links is not what I expected, size of files is not what I expected, the permissions are not all what I expected and then it says that all files are directory and add a "-" after that. I know it's probably caused by all the printf but I don't know how to fix this.

here is my code:

int main() {
    char* curr_dir = NULL;
    DIR* dir = NULL;
    struct dirent* entity = NULL;
    struct stat fileStat;
    struct passwd* pwd;
    struct group* gid;

    curr_dir = getenv("PWD");//current directory with PWD
    if (curr_dir==NULL){
        printf("ERROR: j'ai pas pris le repertoire courrant");
    }


    dir = opendir("/Users/seven/Desktop/Programmazione/TP");
    if(dir == NULL) {
        printf("ERROR: j'ai pas pue ouvrir le repertoire");
    }

    while((entity = readdir(dir)) != NULL){
        stat(entity->d_name, &fileStat);
        printf((S_ISDIR(fileStat.st_mode)) ? "d" : "-");
        printf((S_ISLNK(fileStat.st_mode)) ? "l" : "-");
        printf((S_ISSOCK(fileStat.st_mode)) ? "s" : "-");
        printf((S_ISFIFO(fileStat.st_mode)) ? "p" : "-");
        printf((S_ISBLK(fileStat.st_mode)) ? "b" : "-");
        printf((S_ISCHR(fileStat.st_mode)) ? "c" : "-");
        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("\t %u", fileStat.st_nlink);
        printf("\t %lld", fileStat.st_size);
        pwd = getpwuid(fileStat.st_uid);
        gid = getgrgid(fileStat.st_gid);
        if(pwd != NULL && gid != NULL ){
            printf("\t %s", pwd->pw_name);
            printf("\t %s", gid->gr_name);
        }
        printf("\t %s\n", entity->d_name);

    }

    closedir(dir);
} 

Solution

The entity->d_name doesn't contain the full path of the file. All files you try to stat will be relative to the current working directory, not the one you passed to opendir. So some files will not exist and stat will silently fail (since you don't check for that).

Two possible solutions:

1. Change working directory to the one you use for the opendir call; Or
2. Append the directory and the entity->d_name (with path separator) and pass that appended name to stat.

And of course, add error checking for all calls.

Answered By - Some programmer dude

Answer Checked By - Mary Flores (WPSolving Volunteer)