From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-x82f.google.com (mail-qt1-x82f.google.com [IPv6:2607:f8b0:4864:20::82f]) by sourceware.org (Postfix) with ESMTPS id 0F05C3857C44 for ; Fri, 26 Mar 2021 17:15:18 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 0F05C3857C44 Received: by mail-qt1-x82f.google.com with SMTP id x9so4720957qto.8 for ; Fri, 26 Mar 2021 10:15:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=txH4n7kCgBnC4a76LdFXik5JnqZb20aMJoMilW9EQuU=; b=hHMob7a+Fs8eygDD4mb8OlF8Idrc6Ep7J+LWQy76sn1NEVP+X0ErI1mJmzPi6G3RWi rRfL8rrCBD0Kr31OaAIci106lGhA4e2vfqYRZXUQg6UGZZ+2jZ+sNNIbxZymAjHbFCvq TWAO7zQv4Ycnm5P0nIF6YMOYHpLyxKq2wR7e00Ou6IW5+svTXRJk5TKFTsbdjfXN5BA+ k5B0mfLlxAaFXSwY1PZEl0I1SBZBR8uYbqW4mm1WoWHFJuIkbVgaMxzXGIdFHhdY73aq U2P6Vx3LodK6YOMO/KlM/g85D8ewiTAOSmZNPG6UjWIH3O1EjmbW/WiQNOxCRB33rBB1 hgpw== X-Gm-Message-State: AOAM532fI5o5fG1PyGblibCVRCeecjI+yS6nX7U8tDRDO/21/ONXOUT/ SXHGTXZ29b6qkjelsPvgloclWhwfm4hJHF1F X-Google-Smtp-Source: ABdhPJyFuOFHX8n7So92NfmpdAL6IcwOTDEcV6P+HoeGyenloyzvYBMwiVEjmRy+x/r4kkixN2O+5w== X-Received: by 2002:ac8:520d:: with SMTP id r13mr13301958qtn.38.1616778917508; Fri, 26 Mar 2021 10:15:17 -0700 (PDT) Received: from [192.168.1.132] ([177.194.41.149]) by smtp.gmail.com with ESMTPSA id w78sm7250653qkb.11.2021.03.26.10.15.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 26 Mar 2021 10:15:17 -0700 (PDT) Subject: Re: [PATCH] misc: Fix tst-select timeout handling (BZ#27648) To: Lukasz Majewski , Adhemerval Zanella via Libc-alpha References: <20210325200007.3571113-1-adhemerval.zanella@linaro.org> <20210326104346.05155e6b@jawa> From: Adhemerval Zanella Message-ID: Date: Fri, 26 Mar 2021 14:15:15 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210326104346.05155e6b@jawa> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Mar 2021 17:15:19 -0000 On 26/03/2021 06:43, Lukasz Majewski wrote: > Hi Adhemerval, > >> Instead of polling the stderr, create two pipes and fork to check >> if child timeout as expected similar to tst-pselect.c. Also lower >> the timeout value. > > I'm just wondering why this approach (with pipes) is more safe than > polling stderr? Using the standard file descriptor is tricky because they can be either closed or redirected by the parent.