[PATCH 3/4] Consolidate Linux recv and recvfrom implementation

[Adhemerval Zanella]

On 06/03/2017 11:48, Dmitry V. Levin wrote:
> On Mon, Jan 30, 2017 at 12:02:05PM -0200, Adhemerval Zanella wrote:
>> This patch consolidates the recv Linux syscall implementation on
>> sysdeps/unix/sysv/linux/recv.c.  The changes are:
>>
>>   1. Remove recv and recvfrom from auto-generation syscalls.list on the
>>      architecture that uses __NR_recv.
> 
> Please split this for correctness, e.g.
> 
>   # Remove recvfrom from auto-generation syscalls.list on all Linux
>     architectures.
>   # Remove recv from auto-generation syscalls.list on architectures that
>     use __NR_recv.

On my first local iteration I had it split, but then I rebase them
together because I though since recv maybe call recvfrom syscall
they should be related.  I do not have a strong opinion here, so
I will split in next version.

> 
>>   2. Define __NR_recv for such architectures.
> 
> You surely don't define __NR_* for any architecture, do you?

Yes, this description is off.  I will correct in next version.

> 
>>      It was done instead of
>>      defining in default kernel-features.h because current Linux practice
>>      for new ports are to implement only __NR_recvfrom [1] and it will
>>      require adding new kernel-features for ports that do not require it
>>      (aarch64 for instance).
>>   3. Define __NR_recvfrom as default (__ASSUME_RECVFROM_SYSCALL) and undef
>>      for architectures that do not support it.
> 
> This is also misleading, you probably mean
> 
>   # Define __ASSUME_RECVFROM_SYSCALL by default, undef it for
>     architectures that do not support __NR_recvfrom.

Yes, I will correct it.

> 
>>   4. Remove __ASSUME_RECVFROM_FOR_RECV_SYSCALL and decide to use
>>      __NR_recvfrom for recv generation based on __ASSUME_RECVFROM__SYSCALL.
> 
> Too many underscores in "__ASSUME_RECVFROM__SYSCALL".

Ack.

> 
>> Checked on i686-linux-gnu, x86_64-linux-gnu, x86_64-linux-gnux32,
>> aarch64-linux-gnu, arm-linux-gnueabihf, and powerpc64le-linux-gnu.
>>
>> 	* sysdeps/unix/sysv/linux/alpha/kernel-features.h
>> 	(__ASSUME_RECV_SYSCALL): Define.
>> 	* sysdeps/unix/sysv/linux/arm/kernel-features.h
>> 	(__ASSUME_RECV_SYSCALL): Likewise.
>> 	* sysdeps/unix/sysv/linux/hppa/kernel-features.h
>> 	(__ASSUME_RECV_SYSCALL): Likewise.
>> 	* sysdeps/unix/sysv/linux/ia64/kernel-features.h
>> 	(__ASSUME_RECV_SYSCALL): Likewise.
>> 	* sysdeps/unix/sysv/linux/mips/kernel-features.h
>> 	[_MIPS_SIM == _ABIO32] (__ASSUME_RECV_SYSCALL): Likewise.
>> 	* sysdeps/unix/sysv/linux/i386/kernel-features.h
>> 	(__ASSUME_RECVFROM_SYSCALL): Define whether the kernel supports it.
> 
> This is misleading: the change undefs __ASSUME_RECVFROM_SYSCALL when
> the kernel does not support __NR_recvfrom.

I will fix it.

> 
>> 	(__ASSUME_RECVFROM_FOR_RECV_SYSCALL): Undefine.
> 
> The removal of #define is not undefine, it's remove.

Ack.



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