From mboxrd@z Thu Jan 1 00:00:00 1970 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 BDEF84D599; Wed, 23 Oct 2024 22:48:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729723726; cv=none; b=XAECT7ZhfNskJC0oGu6rNa9G7dhdcQitzp+1WJh79D3OHWjtCrd9dIiHJAL2dsEpGRfP/7TjocuEy61NvoKxTaNK3appH9+hxYMu/XnQCIYx4Z3qH/WnnCPTniaQfQO1tl8K7/XwmeUdSCSTYb0qI+1GymlUbhVyEfb/Or+uStk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729723726; c=relaxed/simple; bh=tQI6xcoW5Wj1FOWko5zJvCpwUmlsidOvfFIzSJxDFMo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=s8D37LKKvJlvT1qrCVKwlgRw7LRuXZ7yBJq0WJxKDvCTkR4VQNwKkWegfBfJkLbeuyGxE9btw9JIKcCiicMzh13S1N+C0piSc9Kb4cS6kQW5vGsosqBztJzLCk0jAM3PxZgr+NmCtlWA1j5/sbI/9fLxiusdAMFUAwiUprcVMmk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B2MxIgOq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B2MxIgOq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DA9AC4CECD; Wed, 23 Oct 2024 22:48:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729723726; bh=tQI6xcoW5Wj1FOWko5zJvCpwUmlsidOvfFIzSJxDFMo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=B2MxIgOqB8YXLhK/4j84W8rZc1bOCoeKveRTbjBHgHlcbNw9VjD4exFHXDU0mVDV8 PhkhzYEXBHQRhCPvKcM1MgedD6xjQqoorZsf9PQgTmqT53WH39gyqTwKwmz/SH5gte lphEmYnVdhlJZO2amcLtAgsu+KqHHvn8KnDRoJKLEG6DJr5Yt9Lmsw2PRUqau+S8Y+ MCtK8auIMTPT3W9cJK5ruBpJHxZs3/0MUu7CPx7tnFu4CVybSlrHReOzE+Y0/LIo9E mmLoNOdW+gf+ze1ppoUpoPkbyip9BooGhdrzOpadq5+IHkht5aQHEyDnuVk2TTBYKm 4pjuiq3yhldQA== Date: Wed, 23 Oct 2024 15:48:44 -0700 From: Namhyung Kim To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Adrian Hunter , Kan Liang , James Clark , Howard Chu , Athira Jajeev , Michael Petlan , Veronika Molnarova , Dapeng Mi , Thomas Richter , Ilya Leoshkevich , Colin Ian King , Weilin Wang , Andi Kleen , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH v3 1/9] tools subcmd: Add non-waitpid check_if_command_finished() Message-ID: References: <20241018054719.1004128-1-irogers@google.com> <20241018054719.1004128-2-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20241018054719.1004128-2-irogers@google.com> On Thu, Oct 17, 2024 at 10:47:11PM -0700, Ian Rogers wrote: > Using waitpid can cause stdout/stderr of the child process to be > lost. Use Linux's /prod//status file to determine if the process > has reached the zombie state. Use the 'status' file rather than 'stat' > to avoid issues around skipping the process name. > > Tested-by: James Clark > Signed-off-by: Ian Rogers > --- > tools/lib/subcmd/run-command.c | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/tools/lib/subcmd/run-command.c b/tools/lib/subcmd/run-command.c > index 4e3a557a2f37..0a764c25c384 100644 > --- a/tools/lib/subcmd/run-command.c > +++ b/tools/lib/subcmd/run-command.c > @@ -2,6 +2,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -217,8 +218,40 @@ static int wait_or_whine(struct child_process *cmd, bool block) > > int check_if_command_finished(struct child_process *cmd) > { > +#ifdef __linux__ Well.. I still don't like this part. But I can live with that as I want the improvements in the test much more. :) Thanks, Namhyung > + char filename[FILENAME_MAX + 12]; > + char status_line[256]; > + FILE *status_file; > + > + /* > + * Check by reading /proc//status as calling waitpid causes > + * stdout/stderr to be closed and data lost. > + */ > + sprintf(filename, "/proc/%d/status", cmd->pid); > + status_file = fopen(filename, "r"); > + if (status_file == NULL) { > + /* Open failed assume finish_command was called. */ > + return true; > + } > + while (fgets(status_line, sizeof(status_line), status_file) != NULL) { > + char *p; > + > + if (strncmp(status_line, "State:", 6)) > + continue; > + > + fclose(status_file); > + p = status_line + 6; > + while (isspace(*p)) > + p++; > + return *p == 'Z' ? 1 : 0; > + } > + /* Read failed assume finish_command was called. */ > + fclose(status_file); > + return 1; > +#else > wait_or_whine(cmd, /*block=*/false); > return cmd->finished; > +#endif > } > > int finish_command(struct child_process *cmd) > -- > 2.47.0.105.g07ac214952-goog >