bug#70219: Bug/Issue with timeout and signals

[Branden R. Williams]

That’s not an accurate representation of what the command actually does. The 
argument after -k MUST be the kill signal code, without the code the command 
fails. The manpage and help document agree with what you are saying but the 
execution of the program fails. 

That functionality is not represented in the manpage or --help. If you used -k 
10 10s it would send a SIGTERM vs SIGKILL. The point is that the argument 
immediately after the -k or --kill-after= is the kill signal code, not the 
duration. The manpage and help file suggest that it should be the duration.

That’s why I am suggesting using a default SIGTERM if the -k or --kill-after= 
is passed so that the duration is the actual argument that follows. If you 
wanted to alter the signal, that’s where the -s flag comes in.


> On Apr 5, 2024, at 4:59 PM, Chris Elvidge <celvidge001@gmail.com> wrote:
> 
> 
> 
> On 05/04/2024 at 16:19, Branden R. Williams via GNU coreutils Bug Reports 
> wrote:
>> I was integrating the timeout command into a shell script and realized the 
>> manpage & the --help docs do not accurately describe how the tool works. In 
>> addition, there appears to be a bug related to arguments passed. I am 
>> running version 9.1.
>> According to the help screen, this command should work:
>>      timeout -k 10s ping 
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__example.com&d=DwICaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=1o61i4CUhS9OzzVMraHh20b966TBpqSO4_0GGRNaLWA&m=aJDfsufl90pc4lE-vjk1Oo94O1RIrEP39t_G7X5-pvl_5ZXtR-2jcnl0a5OxJgGu&s=VjTsmLfaTKmXMJL0S6OXC7PHTK-rxRwmG7skx4FheqY&e=
>>  
>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__example.com_&d=DwICaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=1o61i4CUhS9OzzVMraHh20b966TBpqSO4_0GGRNaLWA&m=aJDfsufl90pc4lE-vjk1Oo94O1RIrEP39t_G7X5-pvl_5ZXtR-2jcnl0a5OxJgGu&s=i2LYw6g0va2Fbz-arA9sTJOn7_G1uY3hN2Pf5pLautc&e=>
>> It fails, however, because the next argument after invoking -k is the kill 
>> signal you want to send. The command (to send a SIGKILL) must be:
> 
> As I understand it, the argument after -k (or --kill-after=) is the time to 
> wait and send the kill signal if the timeout fails.
> So this line:
> 
>>      timeout -k 9 10s ping 
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__example.com&d=DwICaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=1o61i4CUhS9OzzVMraHh20b966TBpqSO4_0GGRNaLWA&m=aJDfsufl90pc4lE-vjk1Oo94O1RIrEP39t_G7X5-pvl_5ZXtR-2jcnl0a5OxJgGu&s=VjTsmLfaTKmXMJL0S6OXC7PHTK-rxRwmG7skx4FheqY&e=
>>  
>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__example.com_&d=DwICaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=1o61i4CUhS9OzzVMraHh20b966TBpqSO4_0GGRNaLWA&m=aJDfsufl90pc4lE-vjk1Oo94O1RIrEP39t_G7X5-pvl_5ZXtR-2jcnl0a5OxJgGu&s=i2LYw6g0va2Fbz-arA9sTJOn7_G1uY3hN2Pf5pLautc&e=>
> 
> sends a kill signal 9 seconds after the timeout, if the timeout hasn't worked.
> 
> The -s option is to change the signal sent (as below).
> 
>> I believe the kill after functionality and docs should be modified to send a 
>> default signal of SIGTERM without an additional argument so the first 
>> iteration above would work. Then you could explain that if you wanted to 
>> send a DIFFERENT signal, use the -s flag that is there to pass one. But 
>> according to the docs, the first command SHOULD work. Even using the 
>> --kill-after= syntax passes in the kill signal into that argument, not the 
>> actual time.
>> Thank you for your consideration and for maintaining such a critical set of 
>> tools!
>> Regards,
>> B
> 
> 
> -- 
> 
> Chris Elvidge
>