From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 122280 invoked by alias); 2 Jun 2017 18:08:57 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 122249 invoked by uid 89); 2 Jun 2017 18:08:55 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 02 Jun 2017 18:08:54 +0000 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 mx1.redhat.com (Postfix) with ESMTPS id 3B837C0467CB; Fri, 2 Jun 2017 18:08:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 3B837C0467CB Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=palves@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 3B837C0467CB Received: from [127.0.0.1] (ovpn04.gateway.prod.ext.ams2.redhat.com [10.39.146.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 92A107F468; Fri, 2 Jun 2017 18:08:56 +0000 (UTC) Subject: Re: [RFA 09/23] Remove close cleanup To: Tom Tromey , gdb-patches@sourceware.org References: <20170503224626.2818-1-tom@tromey.com> <20170503224626.2818-10-tom@tromey.com> From: Pedro Alves Message-ID: Date: Fri, 02 Jun 2017 18:08:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20170503224626.2818-10-tom@tromey.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-SW-Source: 2017-06/txt/msg00060.txt.bz2 Patch looks good. The bit below made me stop for a second: On 05/03/2017 11:46 PM, Tom Tromey wrote: > @@ -901,64 +900,59 @@ linux_mntns_access_fs (pid_t pid) > if (ns == NULL) > return MNSH_FS_DIRECT; > > - old_chain = make_cleanup (null_cleanup, NULL); > - > fd = gdb_open_cloexec (linux_ns_filename (ns, pid), O_RDONLY, 0); > if (fd < 0) > - goto error; > - > - make_cleanup_close (fd); > + return MNSH_FS_ERROR; > > - if (fstat (fd, &sb) != 0) > - goto error; > + /* Introduce a new scope here so we can reset errno after > + closing. */ > + { > + gdb::fd_closer close_fd (fd); > Would the following be too clever? /* Restore errno on exit to the value saved by the last save() call. Ctor saves. */ struct scoped_errno_restore { scoped_errno_restore () { save (); } ~scoped_errno_restore () { errno = m_value; } /* Take a snapshot of current errno. */ void save () { m_value = errno; } private: int m_value; }; scoped_errno_restore restore_errno; gdb::fd_closer close_fd (fd); /* Save errno and return MNSH_FS_ERROR. */ auto fs_err = [&] () { restore_errno.save (); return MNSH_FS_ERROR; }; if (fstat (fd, &sb) != 0) return fs_err (); (...) helper = linux_mntns_get_helper (); if (helper == NULL) return fs_err (); size = mnsh_send_setns (helper, fd, 0); if (size < 0) return fs_err (); [It gets rid of both the scope, and the gotos.] Thanks, Pedro Alves