Re: [kvm-unit-tests RFC v3 10/13] s390x: Add linemode buffer to fix newline on every print

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On 2018-12-18 10:26, Janosch Frank wrote:
> Linemode seems to add a newline for each sent message which makes
> reading rather hard. Hence we add a small buffer that and only print
> if it's full or a newline is encountered.
> 
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
>  lib/s390x/sclp-console.c | 21 +++++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/s390x/sclp-console.c b/lib/s390x/sclp-console.c
> index f0ce6a0..34edae5 100644
> --- a/lib/s390x/sclp-console.c
> +++ b/lib/s390x/sclp-console.c
> @@ -88,6 +88,9 @@ static uint8_t _ascebc[256] = {
>  };
>  
>  static bool initialized;
> +static char lm_buff[120];
> +static unsigned char lm_buff_off;
> +
>  
>  static void sclp_print_ascii(const char *str)
>  {
> @@ -116,6 +119,18 @@ static void sclp_print_lm(const char *str)
>  	struct mdb *mdb;
>  	struct mto *mto;
>  	struct go *go;
> +	char *nl;
> +
> +	len = strlen(str);
> +	len = len < (sizeof(lm_buff) - lm_buff_off) ? len : (sizeof(lm_buff) - lm_buff_off);
> +	nl = strchr(str, '\n');
> +	if ((lm_buff_off < sizeof(lm_buff) - 1)) {
> +		memcpy(&lm_buff[lm_buff_off], str, len);
> +		lm_buff_off += len;
> +	}
> +	/* Buffer not full and no newline */
> +	if (lm_buff_off != sizeof(lm_buff) - 1 && !nl)
> +		return;
>  
>  	sclp_wait_busy();
>  	sclp_busy = true;
> @@ -123,11 +138,11 @@ static void sclp_print_lm(const char *str)
>  	end = (unsigned char *) sccb + 4096 - 1;
>  	memset(sccb, 0, sizeof(*sccb));
>  	ptr = (unsigned char *) &sccb->msg.mdb.mto;
> -	len = strlen(str);
> +	len = strlen(lm_buff);
>  	offset = 0;
>  	do {
>  		for (count = sizeof(*mto); offset < len; count++) {
> -			ch = str[offset++];
> +			ch = lm_buff[offset++];
>  			if ((ch == 0x0a) || (ptr + count > end))
>  				break;
>  			ptr[count] = _ascebc[ch];
> @@ -154,6 +169,8 @@ static void sclp_print_lm(const char *str)
>  	go->type = 1;
>  	sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
>  	sclp_wait_busy();
> +	memset(lm_buff, 0 , sizeof(lm_buff));
> +	lm_buff_off = 0;
>  }
>  
>  /*
> 

That likely does not work as expected when someone is printing with the
'\n' not being at the end (printf("Hello\nWor"); printf("ld\n");) ...
but it's certainly better than before, so fine for me if you resend this
the next time without RFC.

 Thomas



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