From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 2FFD73858430 for ; Thu, 11 Nov 2021 14:00:41 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 2FFD73858430 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-334-TAiSONg-NDmdV-gTjNinag-1; Thu, 11 Nov 2021 09:00:28 -0500 X-MC-Unique: TAiSONg-NDmdV-gTjNinag-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6E73C80F04F; Thu, 11 Nov 2021 14:00:27 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.82]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 641CF18A50; Thu, 11 Nov 2021 14:00:26 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella Cc: Adhemerval Zanella via Libc-alpha , leonardo.macchia@gmail.com Subject: Re: [PATCH 2/3] inet: Remove strdupa from nrl_domainname() References: <20211110185832.1931688-1-adhemerval.zanella@linaro.org> <20211110185832.1931688-3-adhemerval.zanella@linaro.org> <87mtmb14wm.fsf@oldenburg.str.redhat.com> <458c6b92-0344-f1d5-748a-38208d8c5713@linaro.org> Date: Thu, 11 Nov 2021 15:00:24 +0100 In-Reply-To: <458c6b92-0344-f1d5-748a-38208d8c5713@linaro.org> (Adhemerval Zanella's message of "Thu, 11 Nov 2021 10:36:21 -0300") Message-ID: <871r3myepz.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-12.7 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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: Thu, 11 Nov 2021 14:00:43 -0000 * Adhemerval Zanella: > On 11/11/2021 05:18, Florian Weimer wrote: >> * Adhemerval Zanella via Libc-alpha: >> >>> We can use the already in place scratch_buffer. >>> >>> Checked on x86_64-linux-gnu. >>> --- >>> inet/getnameinfo.c | 8 ++++---- >>> 1 file changed, 4 insertions(+), 4 deletions(-) >>> >>> diff --git a/inet/getnameinfo.c b/inet/getnameinfo.c >>> index 58ebbb1154..69a94604bd 100644 >>> --- a/inet/getnameinfo.c >>> +++ b/inet/getnameinfo.c >>> @@ -127,10 +127,10 @@ nrl_domainname (void) >>> else >>> { >>> /* We need to preserve the hostname. */ >>> - const char *hstname = strdupa (tmpbuf.data); >>> - while (__gethostbyname_r (hstname, &th, >>> - tmpbuf.data, >>> - tmpbuf.length, >>> + size_t hstnamelen = strlen (tmpbuf.data) + 1; >>> + while (__gethostbyname_r (tmpbuf.data, &th, >>> + tmpbuf.data + hstnamelen, >>> + tmpbuf.length - hstnamelen, >>> &h, &herror)) >>> { >>> if (herror == NETDB_INTERNAL && errno == ERANGE) >> >> Can you use malloc instead? scratch_buffer_grow_preserve is a bit of an >> outlier in the interface. > > It would require to add more complexity, since now we have two allocations > to handle (the hstname and the scratch_buffer) and on fast patch it would > actually require a malloc call, where mostly likely it would be done in > the stack fror scratch_buffer. I am not sure it is really an improvement > here. Fair enough, let's keep the code simple. Thanks, Florian