Function sys_readlink

components/lwp/lwp_syscall.c:8490–8538

* @brief Read the value of a symbolic link. * * This function reads the value of a symbolic link and stores it in the provided buffer. The value is the * path to which the symbolic link points. If the symbolic link is too long to fit in the provided buffer, * the function returns the number of bytes needed to store the entire path (not including the terminating null byte). * * @param[in] pa

 * @see sys_symlink(), sys_lstat()
 */
ssize_t sys_readlink(char* path, char *buf, size_t bufsz)
{
    size_t len, copy_len;
    int err, rtn;
    char *copy_path;

    len = lwp_user_strlen(path);
    if (len <= 0)
    {
        return -EFAULT;
    }

    if (!lwp_user_accessable(buf, bufsz))
    {
        return -EINVAL;
    }

    copy_path = (char*)rt_malloc(len + 1);
    if (!copy_path)
    {
        return -ENOMEM;
    }

    copy_len = lwp_get_from_user(copy_path, path, len);
    copy_path[copy_len] = '\0';

    char *link_fn = (char *)rt_malloc(DFS_PATH_MAX);
    if (link_fn)
    {
        err = dfs_file_readlink(copy_path, link_fn, DFS_PATH_MAX);
        if (err > 0)
        {
            buf[bufsz > err ? err : bufsz] = '\0';
            rtn = lwp_put_to_user(buf, link_fn, bufsz > err ? err : bufsz);
        }
        else
        {
            rtn = -EIO;
        }
        rt_free(link_fn);
    }
    else
    {
        rtn = -ENOMEM;
    }

    rt_free(copy_path);
    return rtn;
}

/**
 * @brief Set the CPU affinity mask of a process.