From patchwork Wed Apr 1 11:09:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 221499 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 402C8C43331 for ; Wed, 1 Apr 2020 11:09:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12F1B2078B for ; Wed, 1 Apr 2020 11:09:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585739369; bh=6lV7qxobFFaW+fzXcEPxK3PmmWN2WP/UtIPMd2/uD8o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PsN2X0brO5Y3xHoZBo5nanfTi6mXe9poHWb4GtimxMk+0hWOR8RpSbDMbQ98O8E5z sZKtLwVzkZG9vARy48NZhInkl5nUeG01NEWG5UoikMF7UnjjxY6ho2RjgsBOAugp8D Wk7vwOCP7pi46c7vxD+TnWi6JFZXUwxXDk+M53QI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732234AbgDALJ2 convert rfc822-to-8bit (ORCPT ); Wed, 1 Apr 2020 07:09:28 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:54367 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732352AbgDALJ1 (ORCPT ); Wed, 1 Apr 2020 07:09:27 -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-239-dM95Zu_jML2EgRodxeAK9w-1; Wed, 01 Apr 2020 07:09:23 -0400 X-MC-Unique: dM95Zu_jML2EgRodxeAK9w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8EB6418A5500; Wed, 1 Apr 2020 11:09:21 +0000 (UTC) Received: from krava.redhat.com (unknown [10.40.194.72]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8427C10027AF; Wed, 1 Apr 2020 11:09:16 +0000 (UTC) From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Yonghong Song , Martin KaFai Lau , David Miller , John Fastabend , Jesper Dangaard Brouer , Wenbo Zhang , KP Singh , Andrii Nakryiko , bgregg@netflix.com, Al Viro Subject: [PATCH 2/3] bpf: Add d_path helper Date: Wed, 1 Apr 2020 13:09:06 +0200 Message-Id: <20200401110907.2669564-3-jolsa@kernel.org> In-Reply-To: <20200401110907.2669564-1-jolsa@kernel.org> References: <20200401110907.2669564-1-jolsa@kernel.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kernel.org Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Adding d_path helper function that returns full path for give 'struct path' object, which needs to be the kernel BTF 'path' object. The helper calls directly d_path function. Updating also bpf.h tools uapi header and adding 'path' to bpf_helpers_doc.py script. Signed-off-by: Jiri Olsa --- include/uapi/linux/bpf.h | 14 +++++++++++++- kernel/trace/bpf_trace.c | 31 +++++++++++++++++++++++++++++++ scripts/bpf_helpers_doc.py | 2 ++ tools/include/uapi/linux/bpf.h | 14 +++++++++++++- 4 files changed, 59 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 2e29a671d67e..8da1b4750364 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3025,6 +3025,17 @@ union bpf_attr { * * **-EOPNOTSUPP** Unsupported operation, for example a * call from outside of TC ingress. * * **-ESOCKTNOSUPPORT** Socket type not supported (reuseport). + * + * int bpf_d_path(struct path *path, char *buf, u32 sz) + * Description + * Return full path for given 'struct path' object, which + * needs to be the kernel BTF 'path' object. The path is + * returned in buffer provided 'buf' of size 'sz'. + * + * Return + * length of returned string on success, or a negative + * error in case of failure + * */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3151,7 +3162,8 @@ union bpf_attr { FN(xdp_output), \ FN(get_netns_cookie), \ FN(get_current_ancestor_cgroup_id), \ - FN(sk_assign), + FN(sk_assign), \ + FN(d_path), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index ca1796747a77..6ca390b2b26e 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -779,6 +779,35 @@ static const struct bpf_func_proto bpf_send_signal_thread_proto = { .arg1_type = ARG_ANYTHING, }; +BPF_CALL_3(bpf_d_path, struct path *, path, char *, buf, u32, sz) +{ + char *p = d_path(path, buf, sz - 1); + int len; + + if (IS_ERR(p)) { + len = PTR_ERR(p); + } else { + len = strlen(p); + if (len && p != buf) { + memmove(buf, p, len); + buf[len] = 0; + } + } + + return len; +} + +static u32 bpf_d_path_btf_ids[3]; +static const struct bpf_func_proto bpf_d_path_proto = { + .func = bpf_d_path, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, + .btf_id = bpf_d_path_btf_ids, +}; + const struct bpf_func_proto * bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -1224,6 +1253,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_xdp_output: return &bpf_xdp_output_proto; #endif + case BPF_FUNC_d_path: + return &bpf_d_path_proto; default: return raw_tp_prog_func_proto(func_id, prog); } diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py index f43d193aff3a..8f62cbc4c3ff 100755 --- a/scripts/bpf_helpers_doc.py +++ b/scripts/bpf_helpers_doc.py @@ -418,6 +418,7 @@ class PrinterHelpers(Printer): 'struct __sk_buff', 'struct sk_msg_md', 'struct xdp_md', + 'struct path', ] known_types = { '...', @@ -450,6 +451,7 @@ class PrinterHelpers(Printer): 'struct sk_reuseport_md', 'struct sockaddr', 'struct tcphdr', + 'struct path', } mapped_types = { 'u8': '__u8', diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 2e29a671d67e..8da1b4750364 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3025,6 +3025,17 @@ union bpf_attr { * * **-EOPNOTSUPP** Unsupported operation, for example a * call from outside of TC ingress. * * **-ESOCKTNOSUPPORT** Socket type not supported (reuseport). + * + * int bpf_d_path(struct path *path, char *buf, u32 sz) + * Description + * Return full path for given 'struct path' object, which + * needs to be the kernel BTF 'path' object. The path is + * returned in buffer provided 'buf' of size 'sz'. + * + * Return + * length of returned string on success, or a negative + * error in case of failure + * */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3151,7 +3162,8 @@ union bpf_attr { FN(xdp_output), \ FN(get_netns_cookie), \ FN(get_current_ancestor_cgroup_id), \ - FN(sk_assign), + FN(sk_assign), \ + FN(d_path), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call