From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44662) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XSqAx-0003Ns-IS for qemu-devel@nongnu.org; Sat, 13 Sep 2014 12:27:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XSqAr-0003at-IN for qemu-devel@nongnu.org; Sat, 13 Sep 2014 12:27:51 -0400 Sender: Stratos Psomadakis Message-ID: <54147082.5000904@grnet.gr> Date: Sat, 13 Sep 2014 19:27:46 +0300 From: Stratos Psomadakis MIME-Version: 1.0 References: <87wq991g1c.fsf@blackfin.pond.sub.org> <1410530852-13631-1-git-send-email-psomas@grnet.gr> <20140912112110.3b61c84b@redhat.com> <541326D0.4040102@grnet.gr> <20140912131933.05b74346@redhat.com> In-Reply-To: <20140912131933.05b74346@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="44EU9BLQPEN4LxVNrgAKMx983X0GE2imp" Subject: Re: [Qemu-devel] [synnefo-devel] Re: [PATCH resend 1/2] monitor: Reset HMP mon->rs on CHR_EVENT_CLOSED List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luiz Capitulino Cc: synnefo-devel@googlegroups.com, qemu-devel@nongnu.org, armbru@redhat.com, qemu-stable@nongnu.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --44EU9BLQPEN4LxVNrgAKMx983X0GE2imp Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 12/09/2014 08:19 =CE=BC=CE=BC, Luiz Capitulino wrote: > On Fri, 12 Sep 2014 20:01:04 +0300 > Stratos Psomadakis wrote: > >> On 12/09/2014 06:21 =CE=BC=CE=BC, Luiz Capitulino wrote: >>> On Fri, 12 Sep 2014 17:07:32 +0300 >>> Stratos Psomadakis wrote: >>> >>>> Commit cdaa86a54 ("Add G_IO_HUP handler for socket chardev") exposed= a bug in >>>> the way the HMP monitor handles its command buffer. When a client cl= oses the >>>> connection to the monitor, tcp_chr_read() will detect the G_IO_HUP c= ondition >>>> and call tcp_chr_disconnect() to close the server-side connection to= o. Due to >>>> the fact that monitor reads 1 byte at a time (for each tcp_chr_read(= )), the >>>> monitor readline state / buffers might contain junk (i.e. a half-fin= ished >>>> command). Thus, without calling readline_restart() on mon->rs upon >>>> CHR_EVENT_CLOSED, future HMP commands will fail. >>> What's your reproducer? >> We have a script that opens a connection to the HMP socket and starts >> sending 'info version' commands to the monitor in a loop. If we kill t= he >> script (in the middle of the loop) and re-run it, we get "unknown >> command" errors from the HMP ("unknown command: 'infinfo'" for example= ). >> >>> Are you using the mux feature? >> Nope (on the cli we use '-monitor unix:.mon,server,nowait' for t= he >> HMP). >> >>> We also reset it >>> in CHR_EVENT_OPENED if the mux feature is not used, why isn't that >>> good enough? >> I checked the code and on CHR_EVENT_OPENED the monitor calls >> readline_show_prompt (when not using mux). This resets the >> last_cmd_index/size readline variables, but the cmd_buf_index/size >> remains intact. I think that readline_restart() is necessary in order = to >> cleanup the readline cmd buf (either in CHR_EVENT_OPENED or in >> CHR_EVENT_CLOSED). > I'm wondering if calling readline_restart() in the CHR_EVENT_CLOSED > can break mux support. But I won't have time to check it today. Maybe > moving the readline_restart() call to right before the > readline_show_prompt() call in the OPENED event is the best thing to do= ? I did some quick tests with a mux chardev (I tried two mux'ed HMP monitors and a serial and an HMP). Calling readline_restart() in CHR_EVENT_CLOSED didn't seem to affect mux support (as far as I could tell). However, calling readline_restart() in CHR_EVENT_OPENED, just before readline_show_prompt(), resolves the issue too, and I think it makes more sense to be called at that point. If you agree, I can resend the modified patch. > >> Thanks, >> Stratos >> >>>> Signed-off-by: Stratos Psomadakis >>>> Signed-off-by: Dimitris Aragiorgis >>>> --- >>>> monitor.c | 1 + >>>> 1 file changed, 1 insertion(+) >>>> >>>> diff --git a/monitor.c b/monitor.c >>>> index 34cee74..7857300 100644 >>>> --- a/monitor.c >>>> +++ b/monitor.c >>>> @@ -5252,6 +5252,7 @@ static void monitor_event(void *opaque, int ev= ent) >>>> break; >>>> =20 >>>> case CHR_EVENT_CLOSED: >>>> + readline_restart(mon->rs); >>>> mon_refcount--; >>>> monitor_fdsets_cleanup(); >>>> break; >> --=20 Stratos Psomadakis --44EU9BLQPEN4LxVNrgAKMx983X0GE2imp Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUFHCCAAoJEO/NY8gC4r+pU6YQANDYAzB9qX8jpQ7i5NsHw9xS w2dObiOv6hi1o80YtHubcPPiHEiuW0bugyDnvc+A015yNPfV/fdxFAA1qPNd2wfq ETOUu6lRoi97E7ctoYakMhG42CGijHVNiFMeYkuGzNTdf2J/CyowVeW+FMeH3Nj7 tzY0OaMlxiNENjFyOu4in8N4r2/IylllYyxqNGzodPsfXhdFFL0NofVEO2rnubN9 XM/5c7jjJgidMdyEpe2cM2OFJqJQYXM9nv0iY58lDSV6PBviHxgIIZ0UHoSmlUOU GeiYChncHaXGcJ5UoydaotcJhwLVX7Bf5ceNETe/wDoh0dxDQQ5XlGNLDYJEwj7n sCbQNnYdnxIT4KNqgP7pV4XCRD2dm0hqzbq7m0rnJfpCklvxfDQNqyRQUjhfgYqz xTfiLwIAakfw/AvZC4mOmStLdHo1QLZ0tBkD16lUF7A2TlS3Ofowzy8MZZpYkm4F bDNoE5uUEK3LVjQ1r3pt6riZ484zZ02iByR68D+LcYFf7Rhg6BBU2tIg2Oli/GWX VLQkWp/wk7Iw+m9FYjl7jYQC3MpwUWtUqubfsEji43fzezIGAw17vfQ92R4b305N odXSem2CK8N95G4LQAF2uXTVaaWxg/Je2T7BAv+PctYTS8X9m27JY5vMQNY7mJ7F bdcxPjc0DH0EDUPoxrOs =X9VT -----END PGP SIGNATURE----- --44EU9BLQPEN4LxVNrgAKMx983X0GE2imp--