Question

I want to list regular files in a directory. However, stat fails for every file.

DIR* dp = NULL;
struct dirent* entry = NULL;
dp = opendir(directory);

if (!dp) { log_err("Could not open directory"); return -1; }

while (entry = readdir(dp))
{
    struct stat s;
    char path[1024]; path[0] = 0;
    strcat(path, directory);
    strcat(path, entry->d_name);

    int status = 0;

    if (status = stat(path, &s))
    {
        if (S_ISREG(s.st_mode))
        {
            printf("%s\n", entry->d_name);
        }
    }
    else
    {
        fprintf(stderr, "Can't stat: %s\n", strerror(errno));
    }
}

closedir(dp);

The output is

Can’t stat: Resource temporarily
unavailable

Can’t stat: Resource temporarily
unavailable

Can’t stat: Resource temporarily
unavailable

(… many times)

errno is set to E_AGAIN (11).

Now, if I printf the resulting path, they are indeed valid file and directory names. The directory is readable, the user I run with does have the rights to do so (it’s the directory where I write the program in).

What is causing this problem, and how can I do this correctly?

Answer 1

stat and many other system calls return 0 on success and -1 on failure. You are incorrectly testing the return value of stat.

Your code should be:

if (!stat(path, &s))
{
    if (S_ISREG(s.st_mode))
    {
        printf("%s\n", entry->d_name);
    }
}
else
{
    fprintf(stderr, "Can't stat: %s\n", strerror(errno));
}