Function dfs_dup_from

components/dfs/dfs_v2/src/dfs.c:760–805

* @brief Duplicate a file descriptor from source table to current process * * @param[in] oldfd is the fd in the designate fd table. * @param[in,out] fdtab is the fd table for oldfd, if empty, use global (_fdtab). * * @return -1 on failed or the allocated file descriptor. */

 * @return -1 on failed or the allocated file descriptor.
 */
int dfs_dup_from(int oldfd, struct dfs_fdtable *fdtab)
{
    int newfd = -1;
    struct dfs_file *file;

    if (dfs_file_lock() != RT_EOK)
    {
        return -RT_ENOSYS;
    }

    if (fdtab == NULL)
    {
        fdtab = &_fdtab;
    }

    /* check old fd */
    if ((oldfd < 0) || (oldfd >= fdtab->maxfd))
    {
        goto exit;
    }
    if (!fdtab->fds[oldfd])
    {
        goto exit;
    }
    /* get a new fd*/
    newfd = fd_new();
    file = fd_get(newfd);
    if (newfd >= 0 && file)
    {
        file->mode = fdtab->fds[oldfd]->mode;
        file->flags = fdtab->fds[oldfd]->flags;
        file->fops = fdtab->fds[oldfd]->fops;
        file->dentry = dfs_dentry_ref(fdtab->fds[oldfd]->dentry);
        file->vnode = fdtab->fds[oldfd]->vnode;
        file->mmap_context = RT_NULL;
        file->data = fdtab->fds[oldfd]->data;
    }

    dfs_file_close(fdtab->fds[oldfd]);

exit:
    fdt_fd_release(fdtab, oldfd);
    dfs_file_unlock();

    return newfd;
}

/**
 * @brief System call to duplicate a file descriptor