On Fri, 30 Jun 2023 14:54:47 +0000
Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
> Without the \r the output of the ASCII console takes a lot of
> additional effort to read in comparison to the line mode console.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> lib/s390x/sclp-console.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/lib/s390x/sclp-console.c b/lib/s390x/sclp-console.c
> index 19c74e46..384080b0 100644
> --- a/lib/s390x/sclp-console.c
> +++ b/lib/s390x/sclp-console.c
> @@ -97,14 +97,27 @@ static void sclp_print_ascii(const char *str)
> {
> int len = strlen(str);
> WriteEventData *sccb = (void *)_sccb;
> + char *str_dest = (char *)&sccb->msg;
> + int i = 0;
>
> sclp_mark_busy();
> memset(sccb, 0, sizeof(*sccb));
> +
> + for (; i < len; i++) {
> + *str_dest = str[i];
> + str_dest++;
> + /* Add a \r to the \n */
> + if (str[i] == '\n') {
> + *str_dest = '\r';
> + str_dest++;
> + }
> + }
> +
> + len = (uintptr_t)str_dest - (uintptr_t)&sccb->msg;
some strings will therefore potentially overflow the SCCB
sclp_print() refuses to print more than 2kB, with this patch that limit
could potentially be crossed
can you please briefly explain in a comment why that is ok? (or maybe
that is not ok? then fix it somehow :) )
> sccb->h.length = offsetof(WriteEventData, msg) + len;
> sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
> sccb->ebh.length = sizeof(EventBufferHeader) + len;
> sccb->ebh.type = SCLP_EVENT_ASCII_CONSOLE_DATA;
> - memcpy(&sccb->msg, str, len);
>
> sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
> }
