Re: [Qemu-devel] [PULL 52/53] char: Remove unwanted crlf conversion

[Greg Kurz <groug@kaod.org>]

On Fri, 8 Jun 2018 14:56:20 -0300
Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:

> On 06/08/2018 02:39 PM, Greg Kurz wrote:
> > On Thu, 31 May 2018 19:16:05 +0200
> > Paolo Bonzini <pbonzini@redhat.com> wrote:
> >   
> >> From: Patryk Olszewski <patryk@fala.ehost.pl>
> >>
> >> 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.
> >>  
> > 
> > But it damages error reporting...
> > 
> > Without this patch:
> > 
> > $ qemu-system-ppc64 -serial stdio -kernel foo
> > foo: No such file or directory
> > qemu-system-ppc64: error loading foo: Failed to load ELF
> > $
> > 
> > With this patch:
> > 
> > $ .mbuild-ppc-for-3.0/obj/ppc64-softmmu/qemu-system-ppc64 -serial stdio -kernel foo
> > foo: No such file or directory
> >                               qemu-system-ppc64: error loading foo: Failed to load ELF
> >                                                                                       $
> > 
> > It is possible to patch vreport() to append an explicit CR:
> > 
> >      error_vprintf(fmt, ap);
> > -    error_printf("\n");
> > +    error_printf("\n\r");
> >  }
> > 
> > but it only fixes the trailing newline of error_report(). Any other newline,
> > eg when using error_append_hint(), will lack the CR... Not sure how to fix
> > this :-\  
> 
> Peter just pushed the fix (ed6b018ef7):
> 
> http://lists.nongnu.org/archive/html/qemu-devel/2018-06/msg02152.html
> 

Ah, cool ! :)

> >   
> >> 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>
> >> ---
> >>  chardev/char-serial.c | 2 +-
> >>  chardev/char-stdio.c  | 2 +-
> >>  2 files changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/chardev/char-serial.c b/chardev/char-serial.c
> >> index feb52e559d..ae548d28da 100644
> >> --- a/chardev/char-serial.c
> >> +++ b/chardev/char-serial.c
> >> @@ -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) {
> >> diff --git a/chardev/char-stdio.c b/chardev/char-stdio.c
> >> index 96375f2ab8..d83e60e787 100644
> >> --- a/chardev/char-stdio.c
> >> +++ b/chardev/char-stdio.c
> >> @@ -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;  
> >