char: Remove unwanted crlf conversion

This patch fixes a bug in serial that made it almost impossible for guest
to communicate with devices through host's serial.

OPOST flag in c_oflag enables output processing letting other flags in
c_oflag take effect. Usually in c_oflag ONLCR flag is also set, which
causes crlf to be sent in place of lf. This breaks binary transmissions.
Unsetting OPOST flag turns off any output processing which fixes the bug.

Bug reports related:
https://bugs.launchpad.net/qemu/+bug/1772086
https://bugs.launchpad.net/qemu/+bug/1407813
https://bugs.launchpad.net/qemu/+bug/1715296
also
https://lists.nongnu.org/archive/html/qemu-devel/2006-06/msg00196.html

Signed-off-by: Patryk Olszewski <patryk@fala.ehost.pl>
Message-Id: <1527105041-21013-1-git-send-email-patryk@fala.ehost.pl>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Patryk Olszewski 2018-05-23 21:50:41 +02:00 committed by Paolo Bonzini
parent ff46d9d4d6
commit 12fb0ac057
2 changed files with 2 additions and 2 deletions

View File

@ -139,7 +139,7 @@ static void tty_serial_init(int fd, int speed,
tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
| INLCR | IGNCR | ICRNL | IXON);
tty.c_oflag |= OPOST;
tty.c_oflag &= ~OPOST;
tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN | ISIG);
tty.c_cflag &= ~(CSIZE | PARENB | PARODD | CRTSCTS | CSTOPB);
switch (data_bits) {

View File

@ -59,7 +59,7 @@ static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo)
if (!echo) {
tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
| INLCR | IGNCR | ICRNL | IXON);
tty.c_oflag |= OPOST;
tty.c_oflag &= ~OPOST;
tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
tty.c_cflag &= ~(CSIZE | PARENB);
tty.c_cflag |= CS8;