Re: [Qemu-devel] [PATCH 03/11] linux-user/strace: add print_sockaddr_ptr() to handle plain/pointer addrlen

[Philippe Mathieu-Daudé]

Hi Laurent,

On 02/17/2018 03:10 PM, Laurent Vivier wrote:
> Le 24/01/2018 à 14:01, Philippe Mathieu-Daudé a écrit :
>> since this argument differs between sendto()/recvfrom()
>>
>> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
>> ---
>>  linux-user/strace.c | 17 +++++++++++++++--
>>  1 file changed, 15 insertions(+), 2 deletions(-)
>>
>> diff --git a/linux-user/strace.c b/linux-user/strace.c
>> index e7272f4ede..9726d9b378 100644
>> --- a/linux-user/strace.c
>> +++ b/linux-user/strace.c
>> @@ -335,12 +335,15 @@ static void print_siginfo(const target_siginfo_t 
>> *tinfo)
>>  }
>>  
>>  static void
>> -print_sockaddr(abi_ulong addr, abi_long addrlen)
>> +print_sockaddr_ptr(abi_ulong addr, abi_long addrlen, bool addrlen_ptr)
>>  {
>>      struct target_sockaddr *sa;
>>      int i;
>>      int sa_family;
>>  
>> +    if (addrlen_ptr) {
>> +        get_user_ual(addrlen, addrlen);
>> +    }
>>      sa = lock_user(VERIFY_READ, addr, addrlen, 1);
>>      if (sa) {
>>          sa_family = tswap16(sa->sa_family);
>> @@ -417,7 +420,17 @@ print_sockaddr(abi_ulong addr, abi_long addrlen)
>>      } else {
>>          print_raw_param("0x"TARGET_ABI_FMT_lx, addr, 0);
>>      }
>> -    gemu_log(", "TARGET_ABI_FMT_ld, addrlen);
>> +    if (addrlen_ptr) {
>> +        gemu_log(", ["TARGET_ABI_FMT_ld"]", addrlen);
>> +    } else {
>> +        gemu_log(", "TARGET_ABI_FMT_ld, addrlen);
>> +    }
>> +}
>> +
>> +static void
>> +print_sockaddr(abi_ulong addr, abi_long addrlen)
>> +{
>> +    print_sockaddr_ptr(addr, addrlen, false);
>>  }
>>  
>>  static void
>>
> 
> Why not only something like:
> 
> static void
> print_sockaddr_ptr(abi_ulong addr, abi_long addrlen_ptr)
> {
>     abi_ulong addrlen;
> 
>     get_user_ual(addrlen, addrlen_ptr);
>     print_sockaddr(addr, addrlen);
> }
> 
> ?

Because we loose the [] around addrlen.

> You should also check addrlen_ptr != NULL (it's allowed with recvfrom()).

OK.

> 
> Thanks,
> Laurent
>