From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52274) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vrd47-0003UH-Hy for qemu-devel@nongnu.org; Fri, 13 Dec 2013 19:26:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vrd41-0000Sk-DO for qemu-devel@nongnu.org; Fri, 13 Dec 2013 19:26:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:62028) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vrd41-0000SZ-61 for qemu-devel@nongnu.org; Fri, 13 Dec 2013 19:26:37 -0500 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id rBE0QYxR002490 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 13 Dec 2013 19:26:34 -0500 Message-ID: <52ABA5EF.5060301@redhat.com> Date: Sat, 14 Dec 2013 01:27:27 +0100 From: Max Reitz MIME-Version: 1.0 References: <1386954633-28905-1-git-send-email-mreitz@redhat.com> <1386954633-28905-17-git-send-email-mreitz@redhat.com> <20131213204335.GD3916@dhcp-200-207.str.redhat.com> In-Reply-To: <20131213204335.GD3916@dhcp-200-207.str.redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5 16/22] blkdebug: Make filename optional List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Fam Zheng , qemu-devel@nongnu.org, Stefan Hajnoczi On 13.12.2013 21:43, Kevin Wolf wrote: > Am 13.12.2013 um 18:10 hat Max Reitz geschrieben: >> There is no problem in giving no filename; in this case, it has to be >> specified through the "image" option. >> >> Signed-off-by: Max Reitz >> --- >> block/blkdebug.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/block/blkdebug.c b/block/blkdebug.c >> index 0c800ae..fdfc6b0 100644 >> --- a/block/blkdebug.c >> +++ b/block/blkdebug.c >> @@ -327,8 +327,10 @@ static void blkdebug_parse_filename(const char *filename, QDict *options, >> /* Parse the blkdebug: prefix */ >> if (!strstart(filename, "blkdebug:", &filename)) { >> /* There was no prefix; therefore, all options have to be already >> - present in the QDict (except for the filename) */ >> - qdict_put(options, "x-image", qstring_from_str(filename)); >> + present in the QDict; if a filename is given, pass it */ >> + if (filename) { > filename can't be NULL here: For a non-NULL input, strstart() doesn't > return NULL, and for a NULL string it segfaults... > > I don't think we have the segfault case here, because calling > bdrv_parse_filename() without having a filename in the first place is > quite pointless. I suspect giving no filename has been working even > before this patch. Right; for NULL input, that function isn't even called ("if (drv->bdrv_parse_filename && filename)" in bdrv_file_open()). Max >> + qdict_put(options, "x-image", qstring_from_str(filename)); >> + } >> return; >> } > Having a test case in the commit would show what your intention was (and > that the implementation doesn't do that). > > Kevin