Re: [Qemu-devel] [PATCH] qemu-char: fix terminal crash when using "-monitor stdio -nographic"

[Li Liu <john.liuli@huawei.com>]

Ping, any more comments? Thanks.

On 2014/8/27 15:40, Li Liu wrote:
> 
> 
> On 2014/8/27 14:44, Markus Armbruster wrote:
>> "john.liuli" <john.liuli@huawei.com> writes:
>>
>>> From: Li Liu <john.liuli@huawei.com>
>>>
>>> Eeay to reproduce, just try "qemu -monitor stdio -nographic"
>>> and type "quit", then the terminal will be crashed.
>>>
>>> There are two pathes try to call tcgetattr of stdio in vl.c:
>>>
>>> 1) Monitor_parse(optarg, "readline");
>>>    .....
>>>    qemu_opts_foreach(qemu_find_opts("chardev"),
>>>                      chardev_init_func, NULL, 1) != 0)
>>>
>>> 2) if (default_serial)
>>>    add_device_config(DEV_SERIAL, "stdio");
>>>    ....
>>>    if (foreach_device_config(DEV_SERIAL, serial_parse) < 0)
>>>
>>> Both of them will trigger qemu_chr_open_stdio which will disable
>>> ECHO attributes. First one has updated the attributes of stdio
>>> by calling qemu_chr_fe_set_echo(chr, false). And the tty
>>> attributes has been saved in oldtty. Then the second path will
>>> redo such actions, and the oldtty is overlapped. So till "quit",
>>> term_exit can't recove the correct attributes.
>>>
>>> Signed-off-by: Li Liu <john.liuli@huawei.com>
>>
>> Yes, failure to restore tty settings is a bug.
>>
>> But is having multiple character devices use the same terminal valid?
> 
> I'm not sure. But I have found such comments in vl.c
> "According to documentation and historically, -nographic redirects
> serial port, parallel port and monitor to stdio"
> 
> Best regards
> Li.
> 
>> If no, can we catch and reject the attempt?
>>
>> [...]
>>
>>
> 
> 
> 
>