From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59114) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d40rN-0001ON-0z for qemu-devel@nongnu.org; Fri, 28 Apr 2017 04:02:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d40rH-0006OI-6w for qemu-devel@nongnu.org; Fri, 28 Apr 2017 04:02:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58964) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d40rG-0006O9-TV for qemu-devel@nongnu.org; Fri, 28 Apr 2017 04:02:31 -0400 From: Markus Armbruster References: <2bc05de0edd61cdcdd3d2b894378a874d1e12327.1493191677.git.maozy.fnst@cn.fujitsu.com> <87shktu8cu.fsf@dusky.pond.sub.org> <20170427163025.GD30599@redhat.com> Date: Fri, 28 Apr 2017 10:02:26 +0200 In-Reply-To: <20170427163025.GD30599@redhat.com> (Daniel P. Berrange's message of "Thu, 27 Apr 2017 17:30:25 +0100") Message-ID: <87lgqlnenh.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH v2 3/4] net/socket: Convert error report message to Error List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: Mao Zhongyi , jasowang@redhat.com, qemu-devel@nongnu.org "Daniel P. Berrange" writes: > On Thu, Apr 27, 2017 at 06:24:17PM +0200, Markus Armbruster wrote: >> No review, just an observation. >> >> Mao Zhongyi writes: >> >> > Currently, net_socket_mcast_create(), net_socket_fd_init_dgram() and >> > net_socket_fd_init() use the function such as fprintf(), perror() to >> > report an error message. >> > >> > Now, convert these functions to Error. >> > >> > CC: jasowang@redhat.com, armbru@redhat.com >> > Signed-off-by: Mao Zhongyi >> > --- >> > net/socket.c | 66 +++++++++++++++++++++++++++++++++++++----------------------- >> > 1 file changed, 41 insertions(+), 25 deletions(-) >> > >> > diff --git a/net/socket.c b/net/socket.c >> > index b0decbe..559e09a 100644 >> > --- a/net/socket.c >> > +++ b/net/socket.c >> [...] >> > @@ -433,25 +437,27 @@ static NetSocketState *net_socket_fd_init_stream(NetClientState *peer, >> > >> > static NetSocketState *net_socket_fd_init(NetClientState *peer, >> > const char *model, const char *name, >> > - int fd, int is_connected) >> > + int fd, int is_connected, >> > + Error **errp) >> > { >> > int so_type = -1, optlen=sizeof(so_type); >> > >> > if(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type, >> > (socklen_t *)&optlen)< 0) { >> > - fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n", >> > + error_setg(errp, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed", >> > fd); >> > closesocket(fd); >> > return NULL; >> > } >> > switch(so_type) { >> > case SOCK_DGRAM: >> > - return net_socket_fd_init_dgram(peer, model, name, fd, is_connected); >> > + return net_socket_fd_init_dgram(peer, model, name, fd, is_connected, errp); >> > case SOCK_STREAM: >> > return net_socket_fd_init_stream(peer, model, name, fd, is_connected); >> > default: >> > /* who knows ... this could be a eg. a pty, do warn and continue as stream */ >> > - fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM or SOCK_STREAM\n", so_type, fd); >> > + error_setg(errp, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM" >> > + " or SOCK_STREAM", so_type, fd); >> >> Not this patches problem: this case is odd, and the comment is bogus. >> If @fd really was a pty, getsockopt() would fail with ENOTSOCK, wouldn't >> it? If @fd is a socket, but neither SOCK_DGRAM nor SOCK_STREAM (say >> SOCK_RAW), why is it safe to continue as if it was SOCK_STREAM? Jason? > > IMHO it is a problem with this patch. Previously we merely printed > a warning & carried on, which is conceptually ok in general, though > dubious here for the reason you say. > > Now we are filling an Error **errp object, and carrying on - this is > conceptually broken anywhere. If an Error ** is filled, we must return. > If we want to carry on, we shouldn't fill Error **. You're right. >> > return net_socket_fd_init_stream(peer, model, name, fd, is_connected); > > IMHO, we just kill this and put return NULL here. If there is a genuine > reason to support something like SOCK_RAW, it should be explicitly > handled, because this default: case will certainly break SOCK_SEQPACKET > and SOCK_RDM which can't be treated as streams. It's either magic or misguided defensive programming. Probably the latter, but I'd like to hear Jason's opinion. If it's *necessary* magic, we can't use error_setg(). Else, we should drop the default, and insert a closesocket(fd) before the final return NULL. >> > } >> > return NULL; >> >> Not reachable. Ugly, but not your patch's concern. > > > Regards, > Daniel