From patchwork Wed May 29 17:36:04 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1107276 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="mAZ3a04z"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45DdDR52dyz9s4V for ; Thu, 30 May 2019 03:36:23 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726205AbfE2RgW (ORCPT ); Wed, 29 May 2019 13:36:22 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:49036 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726054AbfE2RgW (ORCPT ); Wed, 29 May 2019 13:36:22 -0400 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4THTCfM002982 for ; Wed, 29 May 2019 10:36:21 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=sj9s2F5T80KgYKHxJIjF6yomOIk0Lca0i3wIj4qTiv0=; b=mAZ3a04zq2sxJ0Kd4E7a5cxSRUedLX3Zr6SfFp5KfVDJbczIjRoqEvGEPVeCHiqyeLxv zyYLZJxK0p5fa/QVoaxb8WJ9FkCuaQaX7R3hLElN6a99wZaR5xWikhUUJT7DjJdf+Zu0 wqBJPpojvF8XJ7V92q97zZm4C7CDSkRHpog= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2ssvdurjdx-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Wed, 29 May 2019 10:36:20 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::126) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Wed, 29 May 2019 10:36:20 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id 977678617AE; Wed, 29 May 2019 10:36:19 -0700 (PDT) Smtp-Origin-Hostprefix: dev From: Andrii Nakryiko Smtp-Origin-Hostname: dev101.prn2.facebook.com To: , , , , , CC: Andrii Nakryiko Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v2 bpf-next 2/9] libbpf: preserve errno before calling into user callback Date: Wed, 29 May 2019 10:36:04 -0700 Message-ID: <20190529173611.4012579-3-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190529173611.4012579-1-andriin@fb.com> References: <20190529173611.4012579-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-05-29_09:, , signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=916 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905290114 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org pr_warning ultimately may call into user-provided callback function, which can clobber errno value, so we need to save it before that. Acked-by: Song Liu Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index c6c9d632624a..5af331cb8e4f 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -565,12 +565,12 @@ static int bpf_object__elf_init(struct bpf_object *obj) } else { obj->efile.fd = open(obj->path, O_RDONLY); if (obj->efile.fd < 0) { - char errmsg[STRERR_BUFSIZE]; - char *cp = libbpf_strerror_r(errno, errmsg, - sizeof(errmsg)); + char errmsg[STRERR_BUFSIZE], *cp; + err = -errno; + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warning("failed to open %s: %s\n", obj->path, cp); - return -errno; + return err; } obj->efile.elf = elf_begin(obj->efile.fd,