This will allow us to protect gdbserver_fd from the guest.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 gdbstub.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gdbstub.c b/gdbstub.c
index 6081e719c5..057d0d65c5 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1890,15 +1890,16 @@ static int gdbserver_open(int port)
 int gdbserver_start(int port)
 {
     gdbserver_fd = gdbserver_open(port);
-    if (gdbserver_fd < 0)
+    if (gdbserver_fd < 0) {
         return -1;
+    }
     /* accept connections */
     if (!gdb_accept()) {
         close(gdbserver_fd);
         gdbserver_fd = -1;
         return -1;
     }
-    return 0;
+    return gdbserver_fd;
 }
 
 /* Disable gdb stub for child processes.  */
-- 
2.17.0

Hi Richard,

On 05/31/2018 07:49 PM, Richard Henderson wrote:
> This will allow us to protect gdbserver_fd from the guest.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  gdbstub.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/gdbstub.c b/gdbstub.c
> index 6081e719c5..057d0d65c5 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -1890,15 +1890,16 @@ static int gdbserver_open(int port)
>  int gdbserver_start(int port)
>  {
>      gdbserver_fd = gdbserver_open(port);
> -    if (gdbserver_fd < 0)
> +    if (gdbserver_fd < 0) {
>          return -1;
> +    }
>      /* accept connections */
>      if (!gdb_accept()) {
>          close(gdbserver_fd);
>          gdbserver_fd = -1;
>          return -1;
>      }
> -    return 0;
> +    return gdbserver_fd;

I agree with your change, but what about !CONFIG_USER_ONLY?

It should be safe enough documenting the different behaviors in
include/exec/gdbstub.h.

>  }
>  
>  /* Disable gdb stub for child processes.  */
> 

On 05/31/2018 04:15 PM, Philippe Mathieu-Daudé wrote:
> Hi Richard,
> 
> On 05/31/2018 07:49 PM, Richard Henderson wrote:
>> This will allow us to protect gdbserver_fd from the guest.
>>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>  gdbstub.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/gdbstub.c b/gdbstub.c
>> index 6081e719c5..057d0d65c5 100644
>> --- a/gdbstub.c
>> +++ b/gdbstub.c
>> @@ -1890,15 +1890,16 @@ static int gdbserver_open(int port)
>>  int gdbserver_start(int port)
>>  {
>>      gdbserver_fd = gdbserver_open(port);
>> -    if (gdbserver_fd < 0)
>> +    if (gdbserver_fd < 0) {
>>          return -1;
>> +    }
>>      /* accept connections */
>>      if (!gdb_accept()) {
>>          close(gdbserver_fd);
>>          gdbserver_fd = -1;
>>          return -1;
>>      }
>> -    return 0;
>> +    return gdbserver_fd;
> 
> I agree with your change, but what about !CONFIG_USER_ONLY?

It's still a non-negative number, so the success value is still the same.


r~

On 05/31/2018 09:16 PM, Richard Henderson wrote:
> On 05/31/2018 04:15 PM, Philippe Mathieu-Daudé wrote:
>> Hi Richard,
>>
>> On 05/31/2018 07:49 PM, Richard Henderson wrote:
>>> This will allow us to protect gdbserver_fd from the guest.
>>>
>>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>>> ---
>>>  gdbstub.c | 5 +++--
>>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/gdbstub.c b/gdbstub.c
>>> index 6081e719c5..057d0d65c5 100644
>>> --- a/gdbstub.c
>>> +++ b/gdbstub.c
>>> @@ -1890,15 +1890,16 @@ static int gdbserver_open(int port)
>>>  int gdbserver_start(int port)
>>>  {
>>>      gdbserver_fd = gdbserver_open(port);
>>> -    if (gdbserver_fd < 0)
>>> +    if (gdbserver_fd < 0) {
>>>          return -1;
>>> +    }
>>>      /* accept connections */
>>>      if (!gdb_accept()) {
>>>          close(gdbserver_fd);
>>>          gdbserver_fd = -1;
>>>          return -1;
>>>      }
>>> -    return 0;
>>> +    return gdbserver_fd;
>>
>> I agree with your change, but what about !CONFIG_USER_ONLY?
> 
> It's still a non-negative number, so the success value is still the same.

Good point.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

On 31 May 2018 at 23:49, Richard Henderson <richard.henderson@linaro.org> wrote:
> This will allow us to protect gdbserver_fd from the guest.

Ha, I hadn't realised we already had an internal-to-QEMU filedescriptor :-)

thanks
-- PMM

On 06/01/2018 01:59 AM, Peter Maydell wrote:
> On 31 May 2018 at 23:49, Richard Henderson <richard.henderson@linaro.org> wrote:
>> This will allow us to protect gdbserver_fd from the guest.
> 
> Ha, I hadn't realised we already had an internal-to-QEMU filedescriptor :-)

Two, in fact, if you count qemu_logfile.  ;-)


r~

Le 01/06/2018 à 00:49, Richard Henderson a écrit :
> This will allow us to protect gdbserver_fd from the guest.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Laurent Vivier <laurent@vivier.eu>