ssize_t readlink(char *path, int path_len, char *buffer, size_t buffer_len);
The syscall reads the redirected path of a symlink.
The syscalls return the read length on success or -1 on failure, with
the following errno:
EFAULT: Incorrect addresses for the string arguments.
EACCES: MAC forbid this operation.
EINVAL: The passed file is not a symbolic link.