[PATCH] debug: Fix clang mq_open fortify wrapper (BZ 31917)

[Adhemerval Zanella Netto]

On 22/06/24 02:23, Khem Raj wrote:
> This works ok here with clang/main and failing cases are working fine.
> 
> Acked-by: Khem Raj <raj.khem@gmail.com>

Thanks, if no one opposes it I will commit this shortly.

> 
> On Fri, Jun 21, 2024 at 7:08 AM Adhemerval Zanella
> <adhemerval.zanella@linaro.org> wrote:
>>
>> The mqueue.h fortify wrapper for clang added by c23107effbfe5300
>> is not fully correct, where correct 4 argument usage are not
>> being correctly handled.  For instance, while building socat 1.8
>> with a yocto clang based system shows:
>>
>>   ./socat-1.8.0.0/xio-posixmq.c:119:8: error: 'mq_open' is unavailable: mq_open can be called either with 2 or 4 arguments
>>     119 |         mqd = mq_open(name, oflag, opt_mode, NULL);
>>         |               ^
>>   [...] /usr/include/bits/mqueue2.h:66:8: note: 'mq_open' has been explicitly marked unavailable here
>>      66 | __NTH (mq_open (const char *__name, int __oflag, mode_t mode,
>>         |        ^
>>   1 error generated.
>>
>> The correct way to define the wrapper is to set invalid usage
>> with __fortify_clang_unavailable (for the case with 5 or more
>> arguments), followed by the expected ones.  This fix make mq_open
>> similar to current open wrappers.
>>
>> [1] http://www.dest-unreach.org/socat/
>>
>> Reported-by: Khem Raj <raj.khem@gmail.com>
>> ---
>>  rt/bits/mqueue2.h | 20 ++++++++------------
>>  1 file changed, 8 insertions(+), 12 deletions(-)
>>
>> diff --git a/rt/bits/mqueue2.h b/rt/bits/mqueue2.h
>> index d6d2d9012d..386404c0c8 100644
>> --- a/rt/bits/mqueue2.h
>> +++ b/rt/bits/mqueue2.h
>> @@ -59,13 +59,16 @@ __NTH (mq_open (const char *__name, int __oflag, ...))
>>  }
>>  #elif __fortify_use_clang
>>  __fortify_function_error_function __attribute_overloadable__ mqd_t
>> -__NTH (mq_open (const char *__name, int __oflag, mode_t mode))
>> +__NTH (mq_open (__fortify_clang_overload_arg (const char *, , __name),
>> +               int __oflag, mode_t __mode, ...))
>>       __fortify_clang_unavailable ("mq_open can be called either with 2 or 4 arguments");
>>
>> -__fortify_function_error_function __attribute_overloadable__ mqd_t
>> -__NTH (mq_open (const char *__name, int __oflag, mode_t mode,
>> -               struct mq_attr *attr, ...))
>> -     __fortify_clang_unavailable ("mq_open can be called either with 2 or 4 arguments");
>> +__fortify_function __attribute_overloadable__ mqd_t
>> +__NTH (mq_open (__fortify_clang_overload_arg (const char *, ,__name),
>> +               int __oflag, mode_t __mode, struct mq_attr *__attr))
>> +{
>> +  return __mq_open_alias (__name, __oflag, __mode, __attr);
>> +}
>>
>>  __fortify_function __attribute_overloadable__ mqd_t
>>  __NTH (mq_open (__fortify_clang_overload_arg (const char *, ,__name),
>> @@ -76,11 +79,4 @@ __NTH (mq_open (__fortify_clang_overload_arg (const char *, ,__name),
>>  {
>>    return __mq_open_alias (__name, __oflag);
>>  }
>> -
>> -__fortify_function __attribute_overloadable__ mqd_t
>> -__NTH (mq_open (__fortify_clang_overload_arg (const char *, ,__name),
>> -               int __oflag, int __mode, struct mq_attr *__attr))
>> -{
>> -  return __mq_open_alias (__name, __oflag, __mode, __attr);
>> -}
>>  #endif
>> --
>> 2.43.0
>>