Re: [kvm-unit-tests RFC 1/3] lib: s390x: sclp: Add carriage return to line feed

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 6/30/23 17:12, Claudio Imbrenda wrote:
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 :) )

I'd like to see someone find a useful application for printing 2kb in a single printf() call.

Anyway, I could truncate the ASCII after the 2KB limit when adding the \r.

I'm wondering how the line-mode console interprets the \r. If it ignores it, then we could also convert to \n\r for both consoles and check for 2kb when converting.



[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux