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bh=L+relNjYSKG65bcFVjsgpkrfPA/jLjJdRDNwh9JWUWI=; b=aEgZaQPZCU15tz5ZXcZL9gjYhByPAxTAhupfDnwP3JR+DEosrItNTyCBsAhLhkzugEO5xQ +pQWLSONPkN6pXSimFe5yzVwXBQPTnJBr8uAC8ldOgRL1tkFdiZMfOecBJGD4J97oYrVck NreKGnpmbQZhXd3Vm6vbdvifJGRPt08= 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-299-zkFO0VXwOCyb7kQBsp3yKw-1; Fri, 09 Apr 2021 10:19:58 -0400 X-MC-Unique: zkFO0VXwOCyb7kQBsp3yKw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 72FEA87A826; Fri, 9 Apr 2021 14:19:57 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-114-67.ams2.redhat.com [10.36.114.67]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3E1991B400; Fri, 9 Apr 2021 14:19:52 +0000 (UTC) Subject: Re: [PATCH v2 2/2] block/rbd: Add an escape-aware strchr helper To: Connor Kuehl , qemu-block@nongnu.org References: <20210401210150.2127670-1-ckuehl@redhat.com> <20210401210150.2127670-3-ckuehl@redhat.com> From: Max Reitz Message-ID: <168d5be8-8769-39f5-61ac-91cd93822298@redhat.com> Date: Fri, 9 Apr 2021 16:19:51 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, dillaman@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 09.04.21 16:05, Connor Kuehl wrote: > On 4/6/21 9:24 AM, Max Reitz wrote: >> On 01.04.21 23:01, Connor Kuehl wrote: >>> [..] >>> diff --git a/block/rbd.c b/block/rbd.c >>> index 9071a00e3f..c0e4d4a952 100644 >>> --- a/block/rbd.c >>> +++ b/block/rbd.c >>> @@ -134,6 +134,22 @@ static char *qemu_rbd_next_tok(char *src, char >>> delim, char **p) >>>       return src; >>>   } >>> +static char *qemu_rbd_strchr(char *src, char delim) >>> +{ >>> +    char *p; >>> + >>> +    for (p = src; *p; ++p) { >>> +        if (*p == delim) { >>> +            return p; >>> +        } >>> +        if (*p == '\\') { >>> +            ++p; >>> +        } >>> +    } >>> + >>> +    return NULL; >>> +} >>> + >> >> So I thought you could make qemu_rbd_do_next_tok() to do this.  (I >> didn’t say you should, but bear with me.)  That would be possible by >> giving it a new parameter (e.g. @find), and if that is set, return >> @end if *end == delim after the loop, and NULL otherwise. >> >> Now, if you add wrapper functions to make it nice, there’s not much >> more difference in lines added compared to just adding a new function, >> but it does mean your function should basically be the same as >> qemu_rbd_next_tok(), except that no splitting happens, that there is >> no *p, and that @end is returned instead of @src. > > Do you have a strong preference for this? I agree that > qemu_rbd_next_tok() could grow this functionality, but I think it'd be > simpler to keep it separate in the form of qemu_rbd_strchr(). Oh, no, no. I mostly said this so it would be clear why both functions should basically have the same structure, i.e. why a difference in structure might be a sign that something’s wrong. Sorry if I came across as too verbose. >> So there is one difference, and that is that qemu_rbd_next_tok() has >> this condition to skip escaped characters: >> >>      if (*end == '\\' && end[1] != '\0') { >> >> where qemu_rbd_strchr() has only: >> >>      if (*p == '\\') { >> >> And I think qemu_rbd_next_tok() is right; if the string in question >> has a trailing backslash, qemu_rbd_strchr() will ignore the final NUL >> and continue searching past the end of the string. > > Aha, good catch. I'll fix this up. Thanks! Max