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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6B83C433F5 for ; Sun, 5 Dec 2021 20:32:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238661AbhLEUgX convert rfc822-to-8bit (ORCPT ); Sun, 5 Dec 2021 15:36:23 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:13506 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238673AbhLEUgW (ORCPT ); Sun, 5 Dec 2021 15:36:22 -0500 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 1B5742WB012756 for ; Sun, 5 Dec 2021 12:32:54 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 3crrpwjhhb-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sun, 05 Dec 2021 12:32:54 -0800 Received: from intmgw001.25.frc3.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::e) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Sun, 5 Dec 2021 12:32:51 -0800 Received: by devbig019.vll3.facebook.com (Postfix, from userid 137359) id 5FABABFD77AE; Sun, 5 Dec 2021 12:32:50 -0800 (PST) From: Andrii Nakryiko To: , , CC: , Subject: [PATCH bpf-next 06/11] libbpf: add per-program log buffer setter and getter Date: Sun, 5 Dec 2021 12:32:29 -0800 Message-ID: <20211205203234.1322242-7-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211205203234.1322242-1-andrii@kernel.org> References: <20211205203234.1322242-1-andrii@kernel.org> X-FB-Internal: Safe Content-Type: text/plain X-FB-Source: Intern X-Proofpoint-ORIG-GUID: vwvmvRn16a_3Yd0dQY3JQXlOEb-jv0pC X-Proofpoint-GUID: vwvmvRn16a_3Yd0dQY3JQXlOEb-jv0pC Content-Transfer-Encoding: 8BIT X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.790,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2021-12-05_11,2021-12-02_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 suspectscore=0 malwarescore=0 mlxlogscore=999 spamscore=0 bulkscore=0 adultscore=0 phishscore=0 impostorscore=0 clxscore=1034 lowpriorityscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2110150000 definitions=main-2112050124 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Allow to set user-provided log buffer on a per-program basis ([0]). This gives great deal of flexibility in terms of which programs are loaded with logging enabled and where corresponding logs go. Log buffer set with bpf_program__set_log_buf() overrides kernel_log_buf and kernel_log_size settings set at bpf_object open time through bpf_object_open_opts, if any. Adjust bpf_object_load_prog_instance() logic to not perform own log buf allocation and load retry if custom log buffer is provided by the user. [0] Closes: https://github.com/libbpf/libbpf/issues/418 Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 86 ++++++++++++++++++++++++++++++++-------- tools/lib/bpf/libbpf.h | 7 ++++ tools/lib/bpf/libbpf.map | 2 + 3 files changed, 78 insertions(+), 17 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 3fd4e3d5a11f..00807bf8719f 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -331,7 +331,11 @@ struct bpf_program { struct reloc_desc *reloc_desc; int nr_reloc; - int log_level; + + /* BPF verifier log settings */ + char *log_buf; + size_t log_size; + __u32 log_level; struct { int nr; @@ -713,6 +717,9 @@ bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, prog->instances.fds = NULL; prog->instances.nr = -1; + /* inherit object's log_level */ + prog->log_level = obj->log_level; + prog->sec_name = strdup(sec_name); if (!prog->sec_name) goto errout; @@ -6591,8 +6598,10 @@ static int bpf_object_load_prog_instance(struct bpf_object *obj, struct bpf_prog const char *prog_name = NULL; char *cp, errmsg[STRERR_BUFSIZE]; size_t log_buf_size = 0; - char *log_buf = NULL; + char *log_buf = NULL, *tmp; int btf_fd, ret, err; + bool own_log_buf = true; + __u32 log_level = prog->log_level; if (prog->type == BPF_PROG_TYPE_UNSPEC) { /* @@ -6627,7 +6636,7 @@ static int bpf_object_load_prog_instance(struct bpf_object *obj, struct bpf_prog load_attr.line_info_rec_size = prog->line_info_rec_size; load_attr.line_info_cnt = prog->line_info_cnt; } - load_attr.log_level = prog->log_level; + load_attr.log_level = log_level; load_attr.prog_flags = prog->prog_flags; load_attr.fd_array = obj->fd_array; @@ -6648,21 +6657,42 @@ static int bpf_object_load_prog_instance(struct bpf_object *obj, struct bpf_prog *prog_fd = -1; return 0; } -retry_load: - if (log_buf_size) { - log_buf = malloc(log_buf_size); - if (!log_buf) - return -ENOMEM; - *log_buf = 0; +retry_load: + /* if log_level is zero, we don't request logs initiallly even if + * custom log_buf is specified; if the program load fails, then we'll + * bump log_level to 1 and use either custom log_buf or we'll allocate + * our own and retry the load to get details on what failed + */ + if (log_level) { + if (prog->log_buf) { + log_buf = prog->log_buf; + log_buf_size = prog->log_size; + own_log_buf = false; + } else if (obj->log_buf) { + log_buf = obj->log_buf; + log_buf_size = obj->log_size; + own_log_buf = false; + } else { + log_buf_size = max((size_t)BPF_LOG_BUF_SIZE, log_buf_size * 2); + tmp = realloc(log_buf, log_buf_size); + if (!tmp) { + ret = -ENOMEM; + goto out; + } + log_buf = tmp; + log_buf[0] = '\0'; + own_log_buf = true; + } } load_attr.log_buf = log_buf; load_attr.log_size = log_buf_size; - ret = bpf_prog_load(prog->type, prog_name, license, insns, insns_cnt, &load_attr); + load_attr.log_level = log_level; + ret = bpf_prog_load(prog->type, prog_name, license, insns, insns_cnt, &load_attr); if (ret >= 0) { - if (log_buf && load_attr.log_level) { + if (log_level && own_log_buf) { pr_debug("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n", prog->name, log_buf); } @@ -6690,19 +6720,20 @@ static int bpf_object_load_prog_instance(struct bpf_object *obj, struct bpf_prog goto out; } - if (!log_buf || errno == ENOSPC) { - log_buf_size = max((size_t)BPF_LOG_BUF_SIZE, - log_buf_size << 1); - free(log_buf); + if (log_level == 0) { + log_level = 1; goto retry_load; } + /* on ENOSPC, increase log buffer size, unless custom log_buf is specified */ + if (own_log_buf && errno == ENOSPC && log_buf_size < UINT_MAX / 2) + goto retry_load; ret = -errno; cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warn("prog '%s': BPF program load failed: %s\n", prog->name, cp); pr_perm_msg(ret); - if (log_buf && log_buf[0] != '\0') { + if (own_log_buf && log_buf && log_buf[0] != '\0') { pr_warn("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n", prog->name, log_buf); } @@ -6712,7 +6743,8 @@ static int bpf_object_load_prog_instance(struct bpf_object *obj, struct bpf_prog } out: - free(log_buf); + if (own_log_buf) + free(log_buf); return ret; } @@ -8498,6 +8530,26 @@ int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level) return 0; } +const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size) +{ + *log_size = prog->log_size; + return prog->log_buf; +} + +int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size) +{ + if (log_size && !log_buf) + return -EINVAL; + if (prog->log_size > UINT_MAX) + return -EINVAL; + if (prog->obj->loaded) + return -EBUSY; + + prog->log_buf = log_buf; + prog->log_size = log_size; + return 0; +} + #define SEC_DEF(sec_pfx, ptype, atype, flags, ...) { \ .sec = sec_pfx, \ .prog_type = BPF_PROG_TYPE_##ptype, \ diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index ae7cda7ad731..82fd61b674c5 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -538,8 +538,15 @@ bpf_program__set_expected_attach_type(struct bpf_program *prog, LIBBPF_API __u32 bpf_program__flags(const struct bpf_program *prog); LIBBPF_API int bpf_program__set_flags(struct bpf_program *prog, __u32 flags); + +/* Per-program log level and log buffer getters/setters. + * See bpf_object_open_opts comments regarding log_level and log_buf + * interactions. + */ LIBBPF_API __u32 bpf_program__log_level(const struct bpf_program *prog); LIBBPF_API int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level); +LIBBPF_API const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size); +LIBBPF_API int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size); LIBBPF_API int bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd, diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 08cdfe840436..4d483af7dba6 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -423,6 +423,8 @@ LIBBPF_0.6.0 { LIBBPF_0.7.0 { global: bpf_btf_load; + bpf_program__log_buf; bpf_program__log_level; + bpf_program__set_log_buf; bpf_program__set_log_level; }; -- 2.30.2