Re: [glibc] posix: Add terminal control setting support for posix_spawn

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 27/01/2022 08:57, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> I did not considered the closefrom in conjunction with closefrom file
>> action and making a file action does make sense indeed.  Maybe a better
>> approach would be to remove posix_spawnattr_tcsetpgrp_np and
>> posix_spawnattr_tcsetpgrp_np and add:
>>
>>   int posix_spawn_file_actions_tcsetgrp_np (posix_spawn_file_actions_t *,
>> 					    int fd);
>>
>> Similar to posix_spawn_file_actions_addfchdir_np.
>>
>> So to create a process and set the controlling terminal, one can use the
>> following sequence:
>>
>>   int tcfd = open (_PATH_TTY, O_RDONLY, 0600);
>>
>>   posix_spawnattr_t attr;
>>   posix_spawnattr_init (&attr);
>>   posix_spawnattr_setflags (&attr, POSIX_SPAWN_TCSETPGROUP);
> 
> Why is POSIX_SPAWN_TCSETPGROUP needed?
The idea would so caller can check if the action would take, but it does not
make sense with a file action.

> 
>>   posix_spawn_file_actions_t actions;
>>   posix_spawn_file_actions_init (&actions);
>>   posix_spawn_file_actions_tcsetgrp_np (&actions, tcfd);

In fact I think it should be posix_spawn_file_actions_addtcsetgrp_np
to follow other file action naming convention.

>>
>> So users would be able to add a posix_spawn_file_actions_addclose or
>> posix_spawn_file_actions_addclosefrom_np. 
> 
> This would address my concern, yes.
> 
> Thanks,
> Florian
>