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

[Philippe Mathieu-Daudé]

On 06/08/2018 02:39 PM, Greg Kurz wrote:
> On Thu, 31 May 2018 19:16:05 +0200
> Paolo Bonzini <address@hidden> wrote:
> 
>> From: Patryk Olszewski <address@hidden>
>>
>> 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

> 
>> 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 <address@hidden>
>> Message-Id: <address@hidden>
>> Reviewed-by: Markus Armbruster <address@hidden>
>> Reviewed-by: Thomas Huth <address@hidden>
>> Signed-off-by: Paolo Bonzini <address@hidden>
>> ---
>>  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;
>