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 41A19C433F5 for ; Wed, 22 Dec 2021 23:18:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244028AbhLVXSb (ORCPT ); Wed, 22 Dec 2021 18:18:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243957AbhLVXSU (ORCPT ); Wed, 22 Dec 2021 18:18:20 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 86C6FC061395; Wed, 22 Dec 2021 15:18:19 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2749C61D39; Wed, 22 Dec 2021 23:18:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4503CC36AE8; Wed, 22 Dec 2021 23:18:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1640215098; bh=XL2F2sIMNd3mEbXg4dyXDlA3WIZvGQ21ponLFx80OCc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=WKebl9A1kBsJYUZIKPLD8z1wMtz24RCXKjWTNcf7+/Zm4JQm0Y2+aGw9FHYotJVdX 2i+GzPGBdkO/OrC9orqNKMLXpfZrTkz5kM6MqwpnnF5TM8p3YzYWRWfuRzyintkU8p TXSuNh0XBtOqGsTwcVg9X9qaAMsbrmmnsoY6M2b+eXou5Z1hq5+2sSJMQoSt/JRBZ0 DB68cpPjw6sak6SAx3THQiZyB2KiEWXA7rfyLhlmjaeYIDLM06w7GZb2x/w686G2Sw mX83wlZq1Cod4nAnbM0Fwz0OxgBmTvLmUkUf4pyxRCTTj475EcZdChXYHNIG9XvsgC ACXQJi7cXm9Qg== Date: Thu, 23 Dec 2021 08:18:14 +0900 From: Masami Hiramatsu To: Beau Belgrave Cc: rostedt@goodmis.org, linux-trace-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 10/12] user_events: Add sample code for typical usage Message-Id: <20211223081814.1ca544cdf18e29a93f60c597@kernel.org> In-Reply-To: <20211216173511.10390-11-beaub@linux.microsoft.com> References: <20211216173511.10390-1-beaub@linux.microsoft.com> <20211216173511.10390-11-beaub@linux.microsoft.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 16 Dec 2021 09:35:09 -0800 Beau Belgrave wrote: > Add sample code for user_events typical usage to show how to register > and monitor status, as well as to write out data. Ah, here is the sample code. OK. Reviewed-by: Masami Hiramatsu Thanks! > > Signed-off-by: Beau Belgrave > --- > samples/user_events/Makefile | 5 ++ > samples/user_events/example.c | 91 +++++++++++++++++++++++++++++++++++ > 2 files changed, 96 insertions(+) > create mode 100644 samples/user_events/Makefile > create mode 100644 samples/user_events/example.c > > diff --git a/samples/user_events/Makefile b/samples/user_events/Makefile > new file mode 100644 > index 000000000000..7252b589db57 > --- /dev/null > +++ b/samples/user_events/Makefile > @@ -0,0 +1,5 @@ > +# SPDX-License-Identifier: GPL-2.0 > +CFLAGS += -Wl,-no-as-needed -Wall -I../../usr/include > + > +example: example.o > +example.o: example.c > diff --git a/samples/user_events/example.c b/samples/user_events/example.c > new file mode 100644 > index 000000000000..4f5778e441c0 > --- /dev/null > +++ b/samples/user_events/example.c > @@ -0,0 +1,91 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) 2021, Microsoft Corporation. > + * > + * Authors: > + * Beau Belgrave > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/* Assumes debugfs is mounted */ > +const char *data_file = "/sys/kernel/debug/tracing/user_events_data"; > +const char *status_file = "/sys/kernel/debug/tracing/user_events_status"; > + > +static int event_status(char **status) > +{ > + int fd = open(status_file, O_RDONLY); > + > + *status = mmap(NULL, sysconf(_SC_PAGESIZE), PROT_READ, > + MAP_SHARED, fd, 0); > + > + close(fd); > + > + if (*status == MAP_FAILED) > + return -1; > + > + return 0; > +} > + > +static int event_reg(int fd, const char *command, int *status, int *write) > +{ > + struct user_reg reg = {0}; > + > + reg.size = sizeof(reg); > + reg.name_args = (__u64)command; > + > + if (ioctl(fd, DIAG_IOCSREG, ®) == -1) > + return -1; > + > + *status = reg.status_index; > + *write = reg.write_index; > + > + return 0; > +} > + > +int main(int argc, char **argv) > +{ > + int data_fd, status, write; > + char *status_page; > + struct iovec io[2]; > + __u32 count = 0; > + > + if (event_status(&status_page) == -1) > + return errno; > + > + data_fd = open(data_file, O_RDWR); > + > + if (event_reg(data_fd, "test u32 count", &status, &write) == -1) > + return errno; > + > + /* Setup iovec */ > + io[0].iov_base = &write; > + io[0].iov_len = sizeof(write); > + io[1].iov_base = &count; > + io[1].iov_len = sizeof(count); > + > +ask: > + printf("Press enter to check status...\n"); > + getchar(); > + > + /* Check if anyone is listening */ > + if (status_page[status]) { > + /* Yep, trace out our data */ > + writev(data_fd, (const struct iovec *)io, 2); > + > + /* Increase the count */ > + count++; > + > + printf("Something was attached, wrote data\n"); > + } > + > + goto ask; > + > + return 0; > +} > -- > 2.17.1 > -- Masami Hiramatsu