From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C1D1737169 for ; Mon, 1 Jul 2024 04:42:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719808964; cv=none; b=IM1DJLweHpBENSVi5w8/075P1Qiyy10dGzhkEnQcqWjzZ6TnB8yNu6S5z39UP0noYeDKpQei9RDpamAQbrq9Ah0Idu+iLHB3MHk0X3hedRhG94/sC1YWWAkBQWnbU3FdmQRew9yr6syrodmUSnwnSHDC5Je146vD4soDt/DUpc4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719808964; c=relaxed/simple; bh=3WSw+LzwDfsuTLO07J/Gfgu67U+bggq7nxlP2SFbdkc=; h=Date:In-Reply-To:Message-Id:Mime-Version:References:Subject:From: To:Content-Type; b=grj8SrB8DhtLG/sAPjegjes5O3JipgrBAK4cLPenMVq78ItS3zPFp0QuZyEBArvAScrRnL/UKbngvGBO7xC8/dIy+S+SsIGXU77n+nDv1tCVj1AldowAf0Acnm3VgTuD7Gi+r2PT4M/Eol/YeksYd/Y567uMsxe/OyWzsUlRAcY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=cWQpvF4T; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cWQpvF4T" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-6507e2f0615so1545438a12.1 for ; Sun, 30 Jun 2024 21:42:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1719808962; x=1720413762; darn=vger.kernel.org; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=hJaevJbd0eQTHDa7xn1OIMkQuKnrhSd1AMXiSY5R5Xk=; b=cWQpvF4TR0LQ91aZUrUG80AKl+7sQa9kdkGKiAH9uI16gpjdBczaRLIsJ9rSJgkDzx KEckuB61p3wpyuCfIms4QVx7MOsHmey8LfY53Vc2aMEhPlNxaHJldMgcIML0RrELdHtb qlli5PELIJbUWRviMItJREKEIRgrfMqXjABSMTECSHbPWjvDUW5Pldeio641SielBE+l cmYtdAZGELWhdSKVNxq64wiNfIesX7/KjcbnBopigwYEeEkqhGPtP8y42pio4KKvtc6n eZLwBte1a5zsAUqmKDA/xzEF/G8qtwEZsnOkxxZatNAk+V3VjwTMxujfsTcEHGUaXR6J fpDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719808962; x=1720413762; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=hJaevJbd0eQTHDa7xn1OIMkQuKnrhSd1AMXiSY5R5Xk=; b=xNUCXwTlMOuzdwVGzthkPVRy/G5bZzhovYQwKpe+LWrwiBiula0+lHbsNv9daKN4Gw eErgr7kRBzYkKlWbY7axH1wVbEHyeOM1SC21y6I1oJ/mbu5+u3Aua1651VxwfpHL+jwH V7BfQBjs3UAu5yTPYzlcGrYzDgzDqzVU5mYMwUk/b3NzRuRcd9qBYSI9MEsYFipLXhYo wi3dqzZhanhFeYvfJGTuGeqP2GU6Kfx54DaaZ3+OkJXMrEMtkeH4TbCoLWO0osWtF3Om 4Za+fNGexhJ9IM80h63kbRZbcjulcHJG/r2b/FxhuHP9ucP7Z0LlwgR/eGi8WYb8rhFu zE0Q== X-Forwarded-Encrypted: i=1; AJvYcCU2sH+fPnCp8bhmV2AbAlzHoszku46mVLBOOIYp7SIzR1emgduzdEP4Ln4Un5TubhpmocSe89a5iufSY8o4n2gARMi/tPuqH5NXvhAm X-Gm-Message-State: AOJu0YzwoxyMmutVYpnvvPPKuVIsAHNgYPqLum4Ny96RxZGfbkQqI5D8 wj2VPc8WyVOyC6Y9//PfsQKlTu2SFuHf6VgLToeTKW06AeOVbVltXHxdngVJwUf1eII7bcKePWH O1shyeg== X-Google-Smtp-Source: AGHT+IEIzUWDNM21Dmwx3C1YCGQLf5z9VbV+vSSee8+oDr/p/4o0NWDbt/9UqSMxCfs86165f3MQN29AeBtQ X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:7bcd:6ae9:263e:82ff]) (user=irogers job=sendgmr) by 2002:a63:77cc:0:b0:6e4:d411:7c64 with SMTP id 41be03b00d2f7-73cf238df43mr12182a12.3.1719808961796; Sun, 30 Jun 2024 21:42:41 -0700 (PDT) Date: Sun, 30 Jun 2024 21:42:35 -0700 In-Reply-To: <20240701044236.475098-1-irogers@google.com> Message-Id: <20240701044236.475098-2-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240701044236.475098-1-irogers@google.com> X-Mailer: git-send-email 2.45.2.803.g4e1b14247a-goog Subject: [PATCH v2 1/2] tools subcmd: Add non-waitpid check_if_command_finished() From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , James Clark , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" 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. 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..ec06683e77a0 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__ + 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'; + } + /* Read failed assume finish_command was called. */ + fclose(status_file); + return true; +#else wait_or_whine(cmd, /*block=*/false); return cmd->finished; +#endif } int finish_command(struct child_process *cmd) -- 2.45.2.803.g4e1b14247a-goog