how do i fix leaks created by man 2 stat members in c

Question

i am re-implimenting the unix ls command, but when i test for leaks it says:Process 44151: 248 nodes malloced for 45 KB, Process 44151: 28 leaks for 560 total leaked bytes. so i tried to free the pwd, and grp. but it says the i am freeing memory that was never allocated.

static int      one(const struct dirent *unused)
{
    (void)unused;
    return (1);
}

void            ls_l(void)
{
    struct stat     statbuf;
    struct group    *grp;
    struct passwd   *pwd;
    struct dirent   **sd;
    int             n;
    int             i;

    pwd = getpwuid((geteuid()));
    n = scandir(".", &sd, one, alphasort);
    i = 1;
    while (i < n)
    {
        while (strncmp(sd[i]->d_name, ".", 1) == 0)
            i++;
        if (stat(sd[i]->d_name, &statbuf) == 0)
        {
            ft_perm(sd[i]->d_name);
            ft_printf(" %-2d %4s  ", statbuf.st_nlink, pwd->pw_name);
            if ((grp = getgrgid(statbuf.st_gid)) != NULL)
                ft_printf(" %-8.8s %5d %s %s\n",grp->gr_name,
                        (int)statbuf.st_size,ft_group(ctime(&statbuf.st_mtime)),
                        sd[i]->d_name);
            else
                ft_printf(" %-8d %5d %s %s\n", statbuf.st_gid,
                        (int)statbuf.st_size,ft_group(ctime(&statbuf.st_mtime)),
                        sd[i]->d_name);
        }
        free(sd[i]);
        i++;
    }
    free(sd);
}

Answer 1

while (strncmp(sd[i]->d_name, ".", 1) == 0)
            i++;
// code
free(sd[i]);

There's the cause of your memory leak. You're never freeing the elements of sd whose filenames start with a period.

Also, I'd use sd[i]->d_name[0] == '.' for that comparison. strncmp() is overkill for this. A fixed version of your loop:

for (int i = 0; i < n; i += 1) {
   while (i < n && sd[i]->d_name[0] == '.') {
       free(sd[i++]);
   }
   if (i == n) {
      break;
   }

    // code

    free(sd[i]);
}
free(sd);

In addition, this handles cases where every file returned is a dotfile, where your original one would result in reading past the end of the sd array in that situation.