From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BD3EC48BCD for ; Wed, 9 Jun 2021 15:58:39 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id ABA4F60FEB for ; Wed, 9 Jun 2021 15:58:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ABA4F60FEB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53078 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lr0bF-0001Vk-OO for qemu-devel@archiver.kernel.org; Wed, 09 Jun 2021 11:58:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57914) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lr0Yy-0003IS-Bu for qemu-devel@nongnu.org; Wed, 09 Jun 2021 11:56:16 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:31542) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lr0Yv-0006tk-Ga for qemu-devel@nongnu.org; Wed, 09 Jun 2021 11:56:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623254172; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wShB3mfRQz3vX4+x9aHE+Xz5eNnWgcwUXViRK+9d3tg=; b=aJcoe6Y6/A35WEqWUZalOcXnZQjW/ct3m0jpmIhe/eLxVNVNZrLqmWoMF18gBD0kEfxivZ mk1RIklocUObq6aEq42xq8a2o9cVzGzWm/AqrxI+1PU3wWlI2srEkijByxE7zXjCuBQ5m5 6cSZ6IJfxgIOLW9iFzTqtHCfeSrBQBM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-142-xKD7vJ8APU6ulxeKkEf1ew-1; Wed, 09 Jun 2021 11:56:11 -0400 X-MC-Unique: xKD7vJ8APU6ulxeKkEf1ew-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BEF4D800C60 for ; Wed, 9 Jun 2021 15:56:10 +0000 (UTC) Received: from localhost (ovpn-114-102.ams2.redhat.com [10.36.114.102]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4BA965D9C6; Wed, 9 Jun 2021 15:56:01 +0000 (UTC) From: Max Reitz To: qemu-devel@nongnu.org, virtio-fs@redhat.com Subject: [PATCH v2 1/9] virtiofsd: Add TempFd structure Date: Wed, 9 Jun 2021 17:55:43 +0200 Message-Id: <20210609155551.44437-2-mreitz@redhat.com> In-Reply-To: <20210609155551.44437-1-mreitz@redhat.com> References: <20210609155551.44437-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.199, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Dr . David Alan Gilbert" , Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We are planning to add file handles to lo_inode objects as an alternative to lo_inode.fd. That means that everywhere where we currently reference lo_inode.fd, we will have to open a temporary file descriptor that needs to be closed after use. So instead of directly accessing lo_inode.fd, there will be a helper function (lo_inode_fd()) that either returns lo_inode.fd, or opens a new file descriptor with open_by_handle_at(). It encapsulates this result in a TempFd structure to let the caller know whether the FD needs to be closed after use (opened from the handle) or not (copied from lo_inode.fd). By using g_auto(TempFd) to store this result, callers will not even have to care about closing a temporary FD after use. It will be done automatically once the object goes out of scope. Signed-off-by: Max Reitz Reviewed-by: Connor Kuehl --- tools/virtiofsd/passthrough_ll.c | 49 ++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 49c21fd855..a4674aba80 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -174,6 +174,28 @@ struct lo_data { int user_killpriv_v2, killpriv_v2; }; +/** + * Represents a file descriptor that may either be owned by this + * TempFd, or only referenced (i.e. the ownership belongs to some + * other object, and the value has just been copied into this TempFd). + * + * The purpose of this encapsulation is to be used as g_auto(TempFd) + * to automatically clean up owned file descriptors when this object + * goes out of scope. + * + * Use temp_fd_steal() to get an owned file descriptor that will not + * be closed when the TempFd goes out of scope. + */ +typedef struct { + int fd; + bool owned; /* fd owned by this object? */ +} TempFd; + +#define TEMP_FD_INIT ((TempFd) { .fd = -1, .owned = false }) + +static void temp_fd_clear(TempFd *temp_fd); +G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(TempFd, temp_fd_clear); + static const struct fuse_opt lo_opts[] = { { "sandbox=namespace", offsetof(struct lo_data, sandbox), @@ -249,6 +271,33 @@ static struct lo_data *lo_data(fuse_req_t req) return (struct lo_data *)fuse_req_userdata(req); } +/** + * Clean-up function for TempFds + */ +static void temp_fd_clear(TempFd *temp_fd) +{ + if (temp_fd->owned) { + close(temp_fd->fd); + *temp_fd = TEMP_FD_INIT; + } +} + +/** + * Return an owned fd from *temp_fd that will not be closed when + * *temp_fd goes out of scope. + * + * (TODO: Remove __attribute__ once this is used.) + */ +static __attribute__((unused)) int temp_fd_steal(TempFd *temp_fd) +{ + if (temp_fd->owned) { + temp_fd->owned = false; + return temp_fd->fd; + } else { + return dup(temp_fd->fd); + } +} + /* * Load capng's state from our saved state if the current thread * hadn't previously been loaded. -- 2.31.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Max Reitz Date: Wed, 9 Jun 2021 17:55:43 +0200 Message-Id: <20210609155551.44437-2-mreitz@redhat.com> In-Reply-To: <20210609155551.44437-1-mreitz@redhat.com> References: <20210609155551.44437-1-mreitz@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Virtio-fs] [PATCH v2 1/9] virtiofsd: Add TempFd structure List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, virtio-fs@redhat.com Cc: Max Reitz We are planning to add file handles to lo_inode objects as an alternative to lo_inode.fd. That means that everywhere where we currently reference lo_inode.fd, we will have to open a temporary file descriptor that needs to be closed after use. So instead of directly accessing lo_inode.fd, there will be a helper function (lo_inode_fd()) that either returns lo_inode.fd, or opens a new file descriptor with open_by_handle_at(). It encapsulates this result in a TempFd structure to let the caller know whether the FD needs to be closed after use (opened from the handle) or not (copied from lo_inode.fd). By using g_auto(TempFd) to store this result, callers will not even have to care about closing a temporary FD after use. It will be done automatically once the object goes out of scope. Signed-off-by: Max Reitz Reviewed-by: Connor Kuehl --- tools/virtiofsd/passthrough_ll.c | 49 ++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 49c21fd855..a4674aba80 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -174,6 +174,28 @@ struct lo_data { int user_killpriv_v2, killpriv_v2; }; +/** + * Represents a file descriptor that may either be owned by this + * TempFd, or only referenced (i.e. the ownership belongs to some + * other object, and the value has just been copied into this TempFd). + * + * The purpose of this encapsulation is to be used as g_auto(TempFd) + * to automatically clean up owned file descriptors when this object + * goes out of scope. + * + * Use temp_fd_steal() to get an owned file descriptor that will not + * be closed when the TempFd goes out of scope. + */ +typedef struct { + int fd; + bool owned; /* fd owned by this object? */ +} TempFd; + +#define TEMP_FD_INIT ((TempFd) { .fd = -1, .owned = false }) + +static void temp_fd_clear(TempFd *temp_fd); +G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(TempFd, temp_fd_clear); + static const struct fuse_opt lo_opts[] = { { "sandbox=namespace", offsetof(struct lo_data, sandbox), @@ -249,6 +271,33 @@ static struct lo_data *lo_data(fuse_req_t req) return (struct lo_data *)fuse_req_userdata(req); } +/** + * Clean-up function for TempFds + */ +static void temp_fd_clear(TempFd *temp_fd) +{ + if (temp_fd->owned) { + close(temp_fd->fd); + *temp_fd = TEMP_FD_INIT; + } +} + +/** + * Return an owned fd from *temp_fd that will not be closed when + * *temp_fd goes out of scope. + * + * (TODO: Remove __attribute__ once this is used.) + */ +static __attribute__((unused)) int temp_fd_steal(TempFd *temp_fd) +{ + if (temp_fd->owned) { + temp_fd->owned = false; + return temp_fd->fd; + } else { + return dup(temp_fd->fd); + } +} + /* * Load capng's state from our saved state if the current thread * hadn't previously been loaded. -- 2.31.1