Fix the log format problem in devicemodel when using virtio-console with
'stdio' configuration.
In virtio-console, it will change the STDIO's attributes, and will case
the log message after that not align.
e.g:
for (i=0; i<3; i++)
printf('test\n');

The original output would be like this:

test
test
test

After add 'OPOST' to oflag of STDIO, the output would be like this:

test
test
test

(OPOST - Enable implementation-defined output processing)

Signed-off-by: Conghui <conghui.chen@...>
---
devicemodel/hw/pci/virtio/virtio_console.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/devicemodel/hw/pci/virtio/virtio_console.c b/devicemodel/hw/pci/virtio/virtio_console.c
index d3b0fb857..a55284f02 100644
--- a/devicemodel/hw/pci/virtio/virtio_console.c
+++ b/devicemodel/hw/pci/virtio/virtio_console.c
@@ -746,6 +746,7 @@ virtio_console_config_backend(struct virtio_console_backend *be)
saved_tio = tio;
cfmakeraw(&tio);
tio.c_cflag |= CLOCAL;
+ tio.c_oflag |= OPOST;
tcsetattr(fd, TCSANOW, &tio);

if (be->be_type == VIRTIO_CONSOLE_BE_STDIO) {
--
2.25.1

On Thu, Jun 30, 2022 at 11:11:13PM +0800, Conghui Chen wrote:

Fix the log format problem in devicemodel when using virtio-console with
'stdio' configuration.
In virtio-console, it will change the STDIO's attributes, and will case
the log message after that not align.
e.g:
for (i=0; i<3; i++)
printf('test\n');

The original output would be like this:

test
test
test

After add 'OPOST' to oflag of STDIO, the output would be like this:

test
test
test

(OPOST - Enable implementation-defined output processing)

Signed-off-by: Conghui <conghui.chen@...>
---
devicemodel/hw/pci/virtio/virtio_console.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/devicemodel/hw/pci/virtio/virtio_console.c b/devicemodel/hw/pci/virtio/virtio_console.c
index d3b0fb857..a55284f02 100644
--- a/devicemodel/hw/pci/virtio/virtio_console.c
+++ b/devicemodel/hw/pci/virtio/virtio_console.c
@@ -746,6 +746,7 @@ virtio_console_config_backend(struct virtio_console_backend *be)
saved_tio = tio;
cfmakeraw(&tio);
tio.c_cflag |= CLOCAL;
+ tio.c_oflag |= OPOST;

I just googled the OPOST. Looks like the CLOCAL is not performed if
OPOST is not set.

https://www.mkssoftware.com/docs/man5/struct_termios.5.asp

Can you please try to double confirm the behavior? Set OPOST but remove
the CLOCAL?

tcsetattr(fd, TCSANOW, &tio);

if (be->be_type == VIRTIO_CONSOLE_BE_STDIO) {
--
2.25.1

Hi Yu,

https://www.mkssoftware.com/docs/man5/struct_termios.5.asp

Can you please try to double confirm the behavior? Set OPOST but remove
the CLOCAL?

I removed the CLOCAL, and it has no effect on the alignment issue.
Besides, The CLOCAL is used to configurate the connection mode, should has no relationship with the output format.

tcsetattr(fd, TCSANOW, &tio);

if (be->be_type == VIRTIO_CONSOLE_BE_STDIO) {
--
2.25.1