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 A0440C433F5 for ; Thu, 5 May 2022 08:44:38 +0000 (UTC) Received: from localhost ([::1]:42390 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nmX6D-0003FX-NU for qemu-devel@archiver.kernel.org; Thu, 05 May 2022 04:44:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53296) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nmWeO-0006mK-LO for qemu-devel@nongnu.org; Thu, 05 May 2022 04:15:52 -0400 Received: from us-smtp-delivery-74.mimecast.com ([170.10.133.74]:26716) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nmWeM-0007sh-VL for qemu-devel@nongnu.org; Thu, 05 May 2022 04:15:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1651738550; 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=uQOpHYPfgI2lX2Mdfl+rfOehX+tXCf4jqiRnGqO398A=; b=YkahhGYNI8X7AwCUITkWuwcu7AuRNpt+elUi3YnDlFdoQHZnb6bAfLHXwt1HpdLYdEK9Iy ODlnRVZBE2DxZAMdxRiJ4k3U8tj41vJ1TSDIlE5XJiIgLXdQ2/6+rSROY/Ha+LUWtfgDAM E9UrMsN2LOD/xOBM/PmIK3CoYbyCkH0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-172-j1LoL1EyOCKvuj-lwD2gEw-1; Thu, 05 May 2022 04:15:47 -0400 X-MC-Unique: j1LoL1EyOCKvuj-lwD2gEw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 76A0C29ABA35; Thu, 5 May 2022 08:15:46 +0000 (UTC) Received: from localhost (unknown [10.39.208.46]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4A0DAC28102; Thu, 5 May 2022 08:15:45 +0000 (UTC) From: marcandre.lureau@redhat.com To: qemu-devel@nongnu.org Cc: Alexander Bulekov , Bandan Das , Thomas Huth , Hanna Reitz , Markus Armbruster , Konstantin Kostiuk , Stefan Weil , Kevin Wolf , Darren Kenny , Laurent Vivier , Michael Roth , Paolo Bonzini , Qiuhao Li , Stefan Hajnoczi , qemu-block@nongnu.org, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Subject: [PATCH v2 05/15] qga: flatten safe_open_or_create() Date: Thu, 5 May 2022 12:14:21 +0400 Message-Id: <20220505081431.934739-6-marcandre.lureau@redhat.com> In-Reply-To: <20220505081431.934739-1-marcandre.lureau@redhat.com> References: <20220505081431.934739-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 Received-SPF: pass client-ip=170.10.133.74; envelope-from=marcandre.lureau@redhat.com; helo=us-smtp-delivery-74.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Marc-André Lureau There is a bit too much branching in the function, this can be simplified a bit, and have a common exit point thanks to ERRP_PROPAGATE. This also helps with the following error handling changes. Signed-off-by: Marc-André Lureau --- qga/commands-posix.c | 124 ++++++++++++++++++++++--------------------- 1 file changed, 63 insertions(+), 61 deletions(-) diff --git a/qga/commands-posix.c b/qga/commands-posix.c index 69f209af87e6..0ef049650e31 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -339,73 +339,75 @@ find_open_flag(const char *mode_str, Error **errp) static FILE * safe_open_or_create(const char *path, const char *mode, Error **errp) { - Error *local_err = NULL; - int oflag; - - oflag = find_open_flag(mode, &local_err); - if (local_err == NULL) { - int fd; + ERRP_GUARD(); + int oflag, fd = -1; + FILE *f = NULL; + + oflag = find_open_flag(mode, errp); + if (*errp) { + goto end; + } + + /* If the caller wants / allows creation of a new file, we implement it + * with a two step process: open() + (open() / fchmod()). + * + * First we insist on creating the file exclusively as a new file. If + * that succeeds, we're free to set any file-mode bits on it. (The + * motivation is that we want to set those file-mode bits independently + * of the current umask.) + * + * If the exclusive creation fails because the file already exists + * (EEXIST is not possible for any other reason), we just attempt to + * open the file, but in this case we won't be allowed to change the + * file-mode bits on the preexistent file. + * + * The pathname should never disappear between the two open()s in + * practice. If it happens, then someone very likely tried to race us. + * In this case just go ahead and report the ENOENT from the second + * open() to the caller. + * + * If the caller wants to open a preexistent file, then the first + * open() is decisive and its third argument is ignored, and the second + * open() and the fchmod() are never called. + */ + fd = open(path, oflag | ((oflag & O_CREAT) ? O_EXCL : 0), 0); + if (fd == -1 && errno == EEXIST) { + oflag &= ~(unsigned)O_CREAT; + fd = open(path, oflag); + } + if (fd == -1) { + error_setg_errno(errp, errno, + "failed to open file '%s' " + "(mode: '%s')", + path, mode); + goto end; + } - /* If the caller wants / allows creation of a new file, we implement it - * with a two step process: open() + (open() / fchmod()). - * - * First we insist on creating the file exclusively as a new file. If - * that succeeds, we're free to set any file-mode bits on it. (The - * motivation is that we want to set those file-mode bits independently - * of the current umask.) - * - * If the exclusive creation fails because the file already exists - * (EEXIST is not possible for any other reason), we just attempt to - * open the file, but in this case we won't be allowed to change the - * file-mode bits on the preexistent file. - * - * The pathname should never disappear between the two open()s in - * practice. If it happens, then someone very likely tried to race us. - * In this case just go ahead and report the ENOENT from the second - * open() to the caller. - * - * If the caller wants to open a preexistent file, then the first - * open() is decisive and its third argument is ignored, and the second - * open() and the fchmod() are never called. - */ - fd = open(path, oflag | ((oflag & O_CREAT) ? O_EXCL : 0), 0); - if (fd == -1 && errno == EEXIST) { - oflag &= ~(unsigned)O_CREAT; - fd = open(path, oflag); - } + qemu_set_cloexec(fd); - if (fd == -1) { - error_setg_errno(&local_err, errno, "failed to open file '%s' " - "(mode: '%s')", path, mode); - } else { - qemu_set_cloexec(fd); + if ((oflag & O_CREAT) && fchmod(fd, DEFAULT_NEW_FILE_MODE) == -1) { + error_setg_errno(errp, errno, + "failed to set permission 0%03o on new file '%s' (mode: '%s')", + (unsigned)DEFAULT_NEW_FILE_MODE, path, mode); + goto end; + } - if ((oflag & O_CREAT) && fchmod(fd, DEFAULT_NEW_FILE_MODE) == -1) { - error_setg_errno(&local_err, errno, "failed to set permission " - "0%03o on new file '%s' (mode: '%s')", - (unsigned)DEFAULT_NEW_FILE_MODE, path, mode); - } else { - FILE *f; - - f = fdopen(fd, mode); - if (f == NULL) { - error_setg_errno(&local_err, errno, "failed to associate " - "stdio stream with file descriptor %d, " - "file '%s' (mode: '%s')", fd, path, mode); - } else { - return f; - } - } + f = fdopen(fd, mode); + if (f == NULL) { + error_setg_errno(errp, errno, + "failed to associate stdio stream with file descriptor %d, " + "file '%s' (mode: '%s')", + fd, path, mode); + } - close(fd); - if (oflag & O_CREAT) { - unlink(path); - } +end: + if (f == NULL && fd != -1) { + close(fd); + if (oflag & O_CREAT) { + unlink(path); } } - - error_propagate(errp, local_err); - return NULL; + return f; } int64_t qmp_guest_file_open(const char *path, bool has_mode, const char *mode, -- 2.36.0.44.g0f828332d5ac