From patchwork Wed Jul 26 13:00:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13327992 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DECA7A49 for ; Wed, 26 Jul 2023 13:00:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1FD9C433CA; Wed, 26 Jul 2023 13:00:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690376427; bh=DWqlMr8roXaG6O8LFsOi9Etaux6ORDbs/Xvw8dSo2Lk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u2bN3agznoFdF/wMEce7jdyTpYWz8GBbGxgTIcPZJqydyJAektpDOCPqIQh0fJlC4 JWlE1IunzI4uieM1xAE+O0/u3s0QeVPagK9RLHm5vFErscdIxVLqPFFqEmG/smokX4 hDrNXUQtTs9ImiQC3NF24CZboALsPDHqEhyP4nQ/qst8XE5mmb7qkdzvCb4br6hhXa O3afaZZTfvoWkcQztesj3DfKP6od9+IjCDOIZxTCAqCVWbCq5DG6ZkjWkwRqW6wU++ nDft2uFtZTAkq8v9AMK5UHhXTXeV2nIP1eE+PM5xCqZrvEcHuYY6fVYFrORF26EZfd zxsBJSo+9+yQA== From: "Masami Hiramatsu (Google)" To: linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Steven Rostedt , mhiramat@kernel.org, Martin KaFai Lau , bpf@vger.kernel.org, Sven Schnelle , Alexei Starovoitov Subject: [PATCH v3 3/9] bpf/btf: Add a function to search a member of a struct/union Date: Wed, 26 Jul 2023 22:00:23 +0900 Message-Id: <169037642351.607919.10234149030120807556.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <169037639315.607919.2613476171148037242.stgit@devnote2> References: <169037639315.607919.2613476171148037242.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net From: Masami Hiramatsu (Google) Add btf_find_struct_member() API to search a member of a given data structure or union from the member's name. Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Alan Maguire --- Changes in v3: - Remove simple input check. - Fix unneeded IS_ERR_OR_NULL() check for btf_type_by_id(). - Move the code next to btf_get_func_param(). - Use for_each_member() macro instead of for-loop. - Use btf_type_skip_modifiers() instead of btf_type_by_id(). --- include/linux/btf.h | 3 +++ kernel/bpf/btf.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) diff --git a/include/linux/btf.h b/include/linux/btf.h index 20e3a07eef8f..4b10d57ceee0 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -226,6 +226,9 @@ const struct btf_type *btf_find_func_proto(const char *func_name, struct btf **btf_p); const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, s32 *nr); +const struct btf_member *btf_find_struct_member(struct btf *btf, + const struct btf_type *type, + const char *member_name); #define for_each_member(i, struct_type, member) \ for (i = 0, member = btf_type_member(struct_type); \ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index f7b25c615269..5258870030fc 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -958,6 +958,41 @@ const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, s3 return NULL; } +/* + * Find a member of data structure/union by name and return it. + * Return NULL if not found, or -EINVAL if parameter is invalid. + */ +const struct btf_member *btf_find_struct_member(struct btf *btf, + const struct btf_type *type, + const char *member_name) +{ + const struct btf_member *member, *ret; + const char *name; + int i; + + if (!btf_type_is_struct(type)) + return ERR_PTR(-EINVAL); + + for_each_member(i, type, member) { + if (!member->name_off) { + /* unnamed member: dig deeper */ + type = btf_type_skip_modifiers(btf, member->type, NULL); + if (type) { + ret = btf_find_struct_member(btf, type, + member_name); + if (!IS_ERR_OR_NULL(ret)) + return ret; + } + } else { + name = btf_name_by_offset(btf, member->name_off); + if (name && !strcmp(member_name, name)) + return member; + } + } + + return NULL; +} + #define BTF_SHOW_MAX_ITER 10 #define BTF_KIND_BIT(kind) (1ULL << kind)