Re: [Bug-tar] Bug / question in tar

[Eric Blake]

On 03/13/2014 10:35 AM, Paul Eggert wrote:
> On 03/13/2014 01:21 AM, Pavel Raiskup wrote:
>>> We could detect that archive contents are coming from terminal input and
>>> fail immediately (IIRC tar waits indefinitely ATM until it's input is
>>> cut
>>> by ctrl+d or it is killed).
>> I meant something like the patch attached, could you please consider?
>>
>> I tried to write testcase for this and I failed to find proper 'script'
>> alternative tool among coreutils, is there some?  I could rewrite it
>> then.
>>
>> Pavel
> This sort of thing would seem to run counter to the GNU coding
> standards, which say that the behavior a program should not depend on
> the type of device it is used with.
> 
> http://www.gnu.org/prep/standards/html_node/User-Interfaces.html

However, findutils has done just that, so it wouldn't be the first time
that GNU software has been chattier when a terminal is involved:

$ : | xargs --show-limits
Your environment variables take up 3522 bytes
POSIX upper limit on argument length (this system): 2091582
POSIX smallest allowable upper limit on argument length (all systems): 4096
Maximum length of command we could actually use: 2088060
Size of command buffer we are actually using: 131072
$ xargs --show-limits
Your environment variables take up 3522 bytes
POSIX upper limit on argument length (this system): 2091582
POSIX smallest allowable upper limit on argument length (all systems): 4096
Maximum length of command we could actually use: 2088060
Size of command buffer we are actually using: 131072

Execution of xargs will continue now, and it will try to read its input
and run commands; if this is not what you wanted to happen, please type
the end-of-file keystroke.
Warning: echo will be run at least once.  If you do not want that to
happen, then press the interrupt keystroke.

[Ctrl-D]

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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