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Re: [Help-bash] readline does not always handle SIGTERM on reboot
From: |
Chet Ramey |
Subject: |
Re: [Help-bash] readline does not always handle SIGTERM on reboot |
Date: |
Mon, 9 Apr 2018 15:01:59 -0400 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 |
On 4/9/18 2:56 PM, john smith wrote:
> On Mon, Apr 9, 2018 at 7:51 PM, Chet Ramey <address@hidden> wrote:
>> On 4/9/18 12:55 PM, john smith wrote:
>>
>>>> I don't run busybox, so I won't speculate. My first guess would be that
>>>> the signal comes in while bash is ignoring SIGTERM (by catching the signal
>>>> and discarding it).
>>>
>>> I've analyzed bash and readline during the weekend and I learned that
>>> readline() overwrites bash SIGTERM handler and restores it after it
>>> finishes, this is why `kill $$' does not kill the current session but
>>> `(sleep 1; kill $$) &' does.
>>
>> You left out the part where readline resends the signal to the calling
>> application, assuming the calling application hasn't set the signal
>> handler to SIG_IGN (in which case readline would not install a handler
>> for it at all).
>
> Yes, I think I also got this. I wondered why history is saved when I
> simply close my xterm window, now I know that readline() resends
> SIGHUP back to bash in _rl_handle_signal().
That's the same reason that bash catches, but discards, SIGTERM and allows
readline to return EOF.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU address@hidden http://tiswww.cwru.edu/~chet/
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, (continued)
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, john smith, 2018/04/06
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, Chet Ramey, 2018/04/06
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, john smith, 2018/04/06
- Message not available
- Message not available
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, john smith, 2018/04/06
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, john smith, 2018/04/07
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, Chet Ramey, 2018/04/09
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, Chet Ramey, 2018/04/09
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, john smith, 2018/04/09
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, Chet Ramey, 2018/04/09
- Re: [Help-bash] readline does not always handle SIGTERM on reboot, john smith, 2018/04/09
- Re: [Help-bash] readline does not always handle SIGTERM on reboot,
Chet Ramey <=