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Violators will be prosecuted for from ; Wed, 25 Oct 2017 13:49:36 -0600 References: <20171020102517.28385-1-borntraeger@de.ibm.com> From: "Collin L. Walling" Date: Wed, 25 Oct 2017 15:49:31 -0400 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Message-Id: Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] s390-ccw: print carriage return with new lines List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Halil Pasic , Christian Borntraeger , Cornelia Huck Cc: Thomas Huth , Bjoern Walk , David Hildenbrand , Pierre Morel , qemu-devel , Alexander Graf , "Jason J . Herne" , Richard Henderson On 10/20/2017 07:37 AM, Halil Pasic wrote: > > On 10/20/2017 12:25 PM, Christian Borntraeger wrote: >> From: "Collin L. Walling" >> >> 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 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... >> Using MAC address: 02:01:02:03:04:05 >> Reque= sting information via DHCP: 010 >> > The check for buffer overflow was not there previously, or? > > Maybe integrate that in the commit message too. Good point. > >> Signed-off-by: Collin L. Walling >> Signed-off-by: Christian Borntraeger >> --- >> pc-bios/s390-ccw/s390-ccw.h | 3 +++ >> pc-bios/s390-ccw/sclp.c | 17 ++++++++++++++--- >> 2 files changed, 17 insertions(+), 3 deletions(-) >> >> diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h >> index 25d4d21..a8bd204 100644 >> --- a/pc-bios/s390-ccw/s390-ccw.h >> +++ b/pc-bios/s390-ccw/s390-ccw.h >> @@ -33,6 +33,9 @@ typedef unsigned long long __u64; >> #ifndef EBUSY >> #define EBUSY 2 >> #endif >> +#ifndef EFBIG >> +#define EFBIG 3 >> +#endif >> #ifndef NULL >> #define NULL 0 >> #endif >> diff --git a/pc-bios/s390-ccw/sclp.c b/pc-bios/s390-ccw/sclp.c >> index b1fc8ff..4795259 100644 >> --- a/pc-bios/s390-ccw/sclp.c >> +++ b/pc-bios/s390-ccw/sclp.c >> @@ -76,17 +76,28 @@ static int _strlen(const char *str) >> long write(int fd, const void *str, size_t len) >> { >> WriteEventData *sccb =3D (void *)_sccb; >> + const char *p; >> + size_t data_len =3D 0; >> >> if (fd !=3D 1 && fd !=3D 2) { >> return -EIO; >> } >> >> - sccb->h.length =3D sizeof(WriteEventData) + len; >> + for (p =3D str; *p; ++p) { >> + if (data_len > SCCB_DATA_LEN - 1) { >> + return -EFBIG; >> + } > We could also do a partial write or do more that one > sclp_service_call calls. > > I don't think EFBIG is entirely correct here. From the man page: > """ > EFBIG An attempt was made to write a file that exceeds the imp= lementa- > tion-defined maximum file size or the process=E2=80=99s = file size limit, > or to write at a position past the maximum allowed offse= t. > """ > > That's not what we have here IMHO. From my perspective, the error code was a tie between EFBIG (consider max sccb size as the maximum allowed offset) and ENOSPC: """ ENOSPC The device containing the file referred to by /fd/has no room for the data. """ (consider "the file" as the sccb data buffer) However, I extremely doubt we'll ever encounter an overflow from printing during the bios (why would we print something that large?) ... perhaps the check is redundant? > >> + if (*p =3D=3D '\n') { >> + sccb->data[data_len++] =3D '\r'; >> + } >> + sccb->data[data_len++] =3D *p; >> + } >> + >> + sccb->h.length =3D sizeof(WriteEventData) + data_len; >> sccb->h.function_code =3D SCLP_FC_NORMAL_WRITE; >> - sccb->ebh.length =3D sizeof(EventBufferHeader) + len; >> + sccb->ebh.length =3D sizeof(EventBufferHeader) + data_len; >> sccb->ebh.type =3D SCLP_EVENT_ASCII_CONSOLE_DATA; >> sccb->ebh.flags =3D 0; >> - memcpy(sccb->data, str, len); >> >> sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb); >> > Otherwise LGTM > > Halil > > --=20 - Collin L Walling