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Tue, 17 Aug 2021 04:56:48 -0400 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-27-ZiA_INReOteutBARQqN2bw-1; Tue, 17 Aug 2021 04:56:43 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C015B802934 for ; Tue, 17 Aug 2021 08:56:42 +0000 (UTC) Received: from localhost.localdomain (unknown [10.40.194.138]) by smtp.corp.redhat.com (Postfix) with ESMTP id 173D461095; Tue, 17 Aug 2021 08:56:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1629190605; 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=DgjxDJMOxuV2UwHTihO6jrDYgqC8gKTZqmwzvtgQ0QY=; b=PKKrGvl/bv83NDnIbcE17C/ASLSd3GRAYhnvS+Cu5MbNPIj/VfBdu2UJjU/HC1m7sIhDUg NuyczwQ6ntjY9A5Mval0PfO2d+CKCl4dYy1dvL6xxFKJbVhi4mj4PVvtTLGEXeyoacFrGy 4Slcwn8vwSBMDsm6agVlRQ3db05hCZ4= X-MC-Unique: ZiA_INReOteutBARQqN2bw-1 From: Michal Privoznik To: qemu-devel@nongnu.org Subject: [PATCH 2/2] monitor: Report EBADFD if fdset contains invalid FD Date: Tue, 17 Aug 2021 10:56:28 +0200 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mprivozn@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; envelope-from=mprivozn@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.698, 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_H2=-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: marcandre.lureau@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1629190659658100001 Content-Type: text/plain; charset="utf-8" When opening a path that starts with "/dev/fdset/" the control jumps into qemu_parse_fdset() and then into monitor_fdset_dup_fd_add(). In here, corresponding fdset is found and then all FDs from the set are iterated over trying to find an FD that matches expected access mode. For instance, if caller wants O_WRONLY then the FD set has to contain an O_WRONLY FD. If no such FD is found then errno is set to EACCES which results in very misleading error messages, for instance: Could not dup FD for /dev/fdset/3 flags 441: Permission denied There is no permission issue, the problem is that there was no FD within given fdset that was in expected access mode. Therefore, let's set errno to EBADFD, which gives us somewhat better error messages: Could not dup FD for /dev/fdset/3 flags 441: File descriptor in bad state Signed-off-by: Michal Privoznik --- monitor/misc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/monitor/misc.c b/monitor/misc.c index ffe7966870..a0eda0d574 100644 --- a/monitor/misc.c +++ b/monitor/misc.c @@ -1347,7 +1347,7 @@ int monitor_fdset_dup_fd_add(int64_t fdset_id, int fl= ags) } =20 if (fd =3D=3D -1) { - errno =3D EACCES; + errno =3D EBADFD; return -1; } =20 --=20 2.31.1