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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 8ED79E77188 for ; Mon, 6 Jan 2025 09:35:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tUjVq-0000BF-Ar; Mon, 06 Jan 2025 04:35:06 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tUjVo-00009j-4r for qemu-devel@nongnu.org; Mon, 06 Jan 2025 04:35:04 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tUjVl-0000yk-G7 for qemu-devel@nongnu.org; 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Mon, 6 Jan 2025 09:34:54 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.124]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EB3421956088; Mon, 6 Jan 2025 09:34:52 +0000 (UTC) Date: Mon, 6 Jan 2025 09:34:49 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Akihiko Odaki Cc: Jason Wang , qemu-devel@nongnu.org, devel@daynix.com Subject: Re: [PATCH v2 2/2] tap: Use g_spawn_sync() and g_spawn_check_wait_status() Message-ID: References: <20250104-glib-v2-0-12013f3e5782@daynix.com> <20250104-glib-v2-2-12013f3e5782@daynix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250104-glib-v2-2-12013f3e5782@daynix.com> User-Agent: Mutt/2.2.13 (2024-03-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.437, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Sat, Jan 04, 2025 at 05:04:08PM +0900, Akihiko Odaki wrote: > g_spawn_sync() gives an informative message if it fails to execute > the script instead of reporting exiting status 1. > > g_spawn_check_wait_status() also gives an message easier to understand > than the raw value returned by waitpid(). > > Signed-off-by: Akihiko Odaki > --- > net/tap.c | 169 ++++++++++++++++++++++++-------------------------------------- > 1 file changed, 66 insertions(+), 103 deletions(-) > > diff --git a/net/tap.c b/net/tap.c > index ae1c7e398321..392a024f8ed9 100644 > --- a/net/tap.c > +++ b/net/tap.c > @@ -385,56 +385,30 @@ static TAPState *net_tap_fd_init(NetClientState *peer, > return s; > } > > -static void close_all_fds_after_fork(int excluded_fd) > +static void unset_cloexec(gpointer data) > { > - const int skip_fd[] = {STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO, > - excluded_fd}; > - unsigned int nskip = ARRAY_SIZE(skip_fd); > - > - /* > - * skip_fd must be an ordered array of distinct fds, exclude > - * excluded_fd if already included in the [STDIN_FILENO - STDERR_FILENO] > - * range > - */ > - if (excluded_fd <= STDERR_FILENO) { > - nskip--; > - } > - > - qemu_close_all_open_fd(skip_fd, nskip); > + g_assert(!fcntl(GPOINTER_TO_INT(data), F_SETFD, 0)); > } > > static void launch_script(const char *setup_script, const char *ifname, > int fd, Error **errp) > { > - int pid, status; > - char *args[3]; > - char **parg; > + gint status; > + gchar *argv[] = { (gchar *)setup_script, (gchar *)ifname, NULL }; > + g_autoptr(GError) error = NULL; > > /* try to launch network script */ > - pid = fork(); > - if (pid < 0) { > - error_setg_errno(errp, errno, "could not launch network script %s", > - setup_script); > + if (!g_spawn_sync(NULL, argv, NULL, G_SPAWN_CHILD_INHERITS_STDIN, > + unset_cloexec, GINT_TO_POINTER(fd), > + NULL, NULL, &status, &error)) { This unset_cloexec callback is relying on knowledge of current internal impl details of g_spawn_sync. The API docs say that all file descriptors will be closed, except for stdin/out/err. We should not assume glib is doing this by setting O_CLOEXEC, as opposed to directly calling close(). If we need specific FDs to remain open, we neeed to be using the other g_spawn_async_with_pipes_and_fds API that accepts a list of FDs to remain open. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|