From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49074) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e7pAP-0003bi-R8 for qemu-devel@nongnu.org; Thu, 26 Oct 2017 16:54:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e7pAK-0004Ya-Ur for qemu-devel@nongnu.org; Thu, 26 Oct 2017 16:54:17 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:37842) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e7pAK-0004Xs-MJ for qemu-devel@nongnu.org; Thu, 26 Oct 2017 16:54:12 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9QKqbhj095735 for ; Thu, 26 Oct 2017 16:54:08 -0400 Received: from e14.ny.us.ibm.com (e14.ny.us.ibm.com [129.33.205.204]) by mx0a-001b2d01.pphosted.com with ESMTP id 2dupke1dag-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 26 Oct 2017 16:54:08 -0400 Received: from localhost by e14.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 26 Oct 2017 16:54:07 -0400 References: <1509043965-5852-1-git-send-email-walling@linux.vnet.ibm.com> <5edd8fdc-e2b2-2112-afaf-30b63e738e33@suse.de> <501f20dd-26f5-8b14-8f1a-eb2a8e198018@suse.de> From: "Collin L. Walling" Date: Thu, 26 Oct 2017 16:54:02 -0400 MIME-Version: 1.0 In-Reply-To: <501f20dd-26f5-8b14-8f1a-eb2a8e198018@suse.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Message-Id: <47a2b07d-0692-5375-e6f7-16a53d56a0f1@linux.vnet.ibm.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2] s390-ccw: print carriage return with new lines List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf , cohuck@redhat.com, borntraeger@de.ibm.com Cc: thuth@redhat.com, bwalk@linux.vnet.ibm.com, david@redhat.com, pmorel@linux.vnet.ibm.com, qemu-devel@nongnu.org, pasic@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com, rth@twiddle.net On 10/26/2017 04:48 PM, Alexander Graf wrote: > > On 26.10.17 22:37, Collin L. Walling wrote: >> On 10/26/2017 04:25 PM, Alexander Graf wrote: >>> On 26.10.17 20:52, Collin L. Walling wrote: >>>> The sclp console in the s390 bios writes raw data, >>>> leading console emulators (such as virsh console) to >>>> treat a new line ('\n') as just a new line instead >>>> of as a Unix line feed. Because of this, output >>>> appears in a "stair case" pattern. >>>> >>>> Let's print \r\n on every occurrence of a new line >>>> in the string passed to write to amend this issue. >>>> >>>> This is in sync with the guest Linux code in >>>> drivers/s390/char/sclp_vt220.c which also does a line feed >>>> conversion=C2=A0 in the console part of the driver. >>>> >>>> This fixes the s390-ccw and s390-netboot output like >>>> $ virsh start test --console >>>> Domain test started >>>> Connected to domain test >>>> Escape character is ^] >>>> Network boot starting... >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 Using MAC address: 02:01:02:03:04:05 >>>> =20 >>>> Requesting information via DHCP:=C2=A0 010 >>>> >>>> Signed-off-by: Collin L. Walling >>>> Signed-off-by: Christian Borntraeger >>>> --- >>>> =C2=A0 pc-bios/s390-ccw/sclp.c | 16 +++++++++++++--- >>>> =C2=A0 1 file changed, 13 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/pc-bios/s390-ccw/sclp.c b/pc-bios/s390-ccw/sclp.c >>>> index 486fce1..f8ad5ae 100644 >>>> --- a/pc-bios/s390-ccw/sclp.c >>>> +++ b/pc-bios/s390-ccw/sclp.c >>>> @@ -68,17 +68,27 @@ void sclp_setup(void) >>>> =C2=A0 long write(int fd, const void *str, size_t len) >>>> =C2=A0 { >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 WriteEventData *sccb =3D (void *)_sc= cb; >>>> +=C2=A0=C2=A0=C2=A0 const char *p =3D str; >>>> +=C2=A0=C2=A0=C2=A0 size_t data_len =3D 0; >>>> +=C2=A0=C2=A0=C2=A0 size_t i; >>>> =C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (fd !=3D 1 && fd !=3D 2) { >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return -EIO; >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } >>>> =C2=A0 -=C2=A0=C2=A0=C2=A0 sccb->h.length =3D sizeof(WriteEventData= ) + len; >>>> +=C2=A0=C2=A0=C2=A0 for (i =3D len; i > 0; i--) { >>> Where did the bounds check go? If you write(max) before, you were >>> writing max bytes. If you do it now, you end up writing max + n bytes >>> and potentially overflow the array, no? >>> >>> >>> Alex >> I wasn't a fan of the code aesthetics and being that the SCCB write bu= ffer >> allows about 4k bytes of data to be written to it, I felt it was safe = to >> remove it.=C2=A0 It's unlikely we'd be writing that much data in the b= ios, plus >> that check did not exist prior to this fixup. >> >> Though, reading that out loud, it probably isn't the best idea to sacr= ifice >> code robustness for code aesthetics. >> >> for (i =3D len; i > 0; i--) { >> =C2=A0=C2=A0=C2=A0 if (data_len > SCCB_DATA_LEN - 1) { >> =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 return -SOME_ERROR >> =C2=A0=C2=A0=C2=A0 } >> =C2=A0=C2=A0=C2=A0 if (*p =3D=3D '\n') { >> =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 sccb->data[data_len++] =3D '\r'= ; >> =C2=A0=C2=A0=C2=A0 } >> =C2=A0=C2=A0=C2=A0 sccb->data[data_len++] =3D *p; >> =C2=A0=C2=A0=C2=A0 p++; >> } >> >> What do you think? > Normally write() would just write less bytes than it was requested to > write and tell you that in the return value. So how about > > for (i =3D 0; i < len; i++) { > if ((data_len + 1) >=3D SCCB_DATA_LEN) { > /* We would overflow the sccb buffer, abort early */ > len =3D i; > break; > } > > if (*p =3D=3D '\n') { > /* Terminal emulators might need \r\n, so generate it */ > sccb->data[data_len++] =3D '\r'; > } > > sccb->data[data_len++] =3D *p; > p++; > } > > > Alex > Makes sense to me.=C2=A0 I'll let this patch sit on the list for a little while longer before fixing up for v3 in case Imight have missed something else :) Thanks for your time, Alex. --=20 - Collin L Walling