From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 93C3DC63797 for ; Tue, 17 Jan 2023 13:56:57 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.479461.743325 (Exim 4.92) (envelope-from ) id 1pHmSG-0004Cr-1K; Tue, 17 Jan 2023 13:56:48 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 479461.743325; Tue, 17 Jan 2023 13:56:48 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pHmSF-0004Ck-Up; Tue, 17 Jan 2023 13:56:47 +0000 Received: by outflank-mailman (input) for mailman id 479461; Tue, 17 Jan 2023 13:56:46 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pHmSE-0004CK-0U for xen-devel@lists.xenproject.org; Tue, 17 Jan 2023 13:56:46 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pHmSD-00016w-Ib; Tue, 17 Jan 2023 13:56:45 +0000 Received: from 54-240-197-234.amazon.com ([54.240.197.234] helo=[192.168.7.198]) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1pHmSD-0007bv-DU; Tue, 17 Jan 2023 13:56:45 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID; bh=K2Q2SWmwEwQtkuC/lM/GUj/xb6gxQ/qAW28lwp5CeuQ=; b=NZL8Ix6TZCe0AQApJc4gikKtTR ApWcaP3rM1+jjfQmvg5kmMNKIFJywiFoRk7e+P8nFDsrCItFdAClga0L/rLm8c6849zq45gj+3SIh /BF7lVVhjV7KSQo1lofQfNXq7jwoZJ4v8RZYBNpMvpl/pRP+nMnzd6UlsATBdd2ejcM0=; Message-ID: Date: Tue, 17 Jan 2023 13:56:43 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH v3 01/17] tools/xenstore: let talloc_free() preserve errno Content-Language: en-US To: Juergen Gross , xen-devel@lists.xenproject.org Cc: Wei Liu , Anthony PERARD References: <20230117091124.22170-1-jgross@suse.com> <20230117091124.22170-2-jgross@suse.com> From: Julien Grall In-Reply-To: <20230117091124.22170-2-jgross@suse.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Juergen, On 17/01/2023 09:11, Juergen Gross wrote: > Today talloc_free() is not guaranteed to preserve errno, especially in > case a custom destructor is being used. > > So preserve errno in talloc_free(). > > This allows to remove some errno saving outside of talloc.c. > > Signed-off-by: Juergen Gross Reviewed-by: Julien Grall Cheers, > --- > V2: > - drop wrapper (Julien Grall) > --- > tools/xenstore/talloc.c | 21 +++++++++++++-------- > tools/xenstore/xenstored_core.c | 2 -- > 2 files changed, 13 insertions(+), 10 deletions(-) > > diff --git a/tools/xenstore/talloc.c b/tools/xenstore/talloc.c > index d7edcf3a93..23c3a23b19 100644 > --- a/tools/xenstore/talloc.c > +++ b/tools/xenstore/talloc.c > @@ -541,38 +541,39 @@ static void talloc_free_children(void *ptr) > */ > int talloc_free(void *ptr) > { > + int saved_errno = errno; > struct talloc_chunk *tc; > > if (ptr == NULL) { > - return -1; > + goto err; > } > > tc = talloc_chunk_from_ptr(ptr); > > if (tc->null_refs) { > tc->null_refs--; > - return -1; > + goto err; > } > > if (tc->refs) { > talloc_reference_destructor(tc->refs); > - return -1; > + goto err; > } > > if (tc->flags & TALLOC_FLAG_LOOP) { > /* we have a free loop - stop looping */ > - return 0; > + goto success; > } > > if (tc->destructor) { > talloc_destructor_t d = tc->destructor; > if (d == (talloc_destructor_t)-1) { > - return -1; > + goto err; > } > tc->destructor = (talloc_destructor_t)-1; > if (d(ptr) == -1) { > tc->destructor = d; > - return -1; > + goto err; > } > tc->destructor = NULL; > } > @@ -594,10 +595,14 @@ int talloc_free(void *ptr) > tc->flags |= TALLOC_FLAG_FREE; > > free(tc); > + success: > + errno = saved_errno; > return 0; > -} > - > > + err: > + errno = saved_errno; > + return -1; > +} > > /* > A talloc version of realloc. The context argument is only used if > diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c > index 78a3edaa4e..1650821922 100644 > --- a/tools/xenstore/xenstored_core.c > +++ b/tools/xenstore/xenstored_core.c > @@ -771,9 +771,7 @@ struct node *read_node(struct connection *conn, const void *ctx, > return node; > > error: > - err = errno; > talloc_free(node); > - errno = err; > return NULL; > } > -- Julien Grall