Re: Ping: [PATCH v4] system.3: Document bug and workaround when the command name starts with a hypen

["Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>]

Hi Alex,

On 1/18/21 4:45 PM, Alejandro Colomar (man-pages) wrote:
> [removed some CCs]
> 
> On 1/18/21 4:37 PM, Michael Kerrisk (man-pages) wrote:
>> On 1/18/21 4:28 PM, Alejandro Colomar (man-pages) wrote:
>>> Hi Michael,
>>>
>>> Ping!
>>>
>>> And now I noticed a typo in the subject:
>>> s/hypen/hyphen/
>>
>> D'oh! I missed that.
>>
>> In cases like these, where there's already two amendments to the patch,
>> perhaps better is a new complete patch, rather than a ping :-).
> 
> 
> Yup, I considered that for a moment...
> Should've listened to myself :/
> 
> BTW, I don't understand why you ffixed to use .RS/.RE.


Cause that's what we do around code blocks. See man-pages(7),
and all of the other pages :-).

The conclusion of the mail thread on this topic was that .RS/RE don't 
do correct relative indents, IIRC.

Thanks,

Michael


> See
> https://lore.kernel.org/linux-man/eaee2c6e-cbb7-94b2-f6c4-9039d184e129@gmail.com/T/
> 
> Thanks,
> 
> Alex
> 
>>
>> Thanks,
>>
>> Michael
>>
>>
>>> On 1/8/21 3:28 PM, Alejandro Colomar (man-pages) wrote:
>>>>
>>>>
>>>> On 1/8/21 3:22 PM, Alejandro Colomar wrote:
>>>>> man-pages bug: 211029
>>>>>  https://bugzilla.kernel.org/show_bug.cgi?id=211029
>>>>>
>>>>> Complete workaround
>>>>
>>>> Maybe a bit more readable:
>>>> Complete workaround example
>>>>
>>>>
>>>>> (it was too long for the page, but it may be useful here):
>>>>>
>>>>> ......
>>>>>
>>>>> $ sudo ln -s -T /usr/bin/echo /usr/bin/-echo;
>>>>> $ cc -o system_hyphen -x c - ;
>>>>> #include <stdlib.h>
>>>>>
>>>>> int
>>>>> main(void)
>>>>> {
>>>>>     system(" -echo Hello world!");
>>>>>     exit(EXIT_SUCCESS);
>>>>> }
>>>>>
>>>>> $ ./system_hyphen;
>>>>> Hello world!
>>>>>
>>>>> Reported-by: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
>>>>> Cc: Florian Weimer <fweimer@redhat.com>
>>>>> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
>>>>> ---
>>>>>
>>>>> D'oh!
>>>>>
>>>>>  man3/system.3 | 20 ++++++++++++++++++++
>>>>>  1 file changed, 20 insertions(+)
>>>>>
>>>>> diff --git a/man3/system.3 b/man3/system.3
>>>>> index 753d46f7d..ead35ab30 100644
>>>>> --- a/man3/system.3
>>>>> +++ b/man3/system.3
>>>>> @@ -255,6 +255,26 @@ are not executed.
>>>>>  Such risks are especially grave when using
>>>>>  .BR system ()
>>>>>  from a privileged program.
>>>>> +.SH BUGS
>>>>> +.\" [BUG 211029](https://bugzilla.kernel.org/show_bug.cgi?id=211029)
>>>>> +.\" [Glibc bug](https://sourceware.org/bugzilla/show_bug.cgi?id=27143)
>>>>> +.\" [POSIX bug](https://www.austingroupbugs.net/view.php?id=1440)
>>>>> +If the command name starts with a hyphen,
>>>>> +.BR sh (1)
>>>>> +interprets the command name as an option,
>>>>> +and the behavior is undefined.
>>>>> +(See the
>>>>> +.B \-c
>>>>> +option to
>>>>> +.BR sh (1).)
>>>>> +To work around this problem,
>>>>> +prepend the command with a space as in the following call:
>>>>> +.PP
>>>>> +.RS 4
>>>>> +.EX
>>>>> +    system(" \-unfortunate\-command\-name");
>>>>> +.EE
>>>>> +.RE
>>>>>  .SH SEE ALSO
>>>>>  .BR sh (1),
>>>>>  .BR execve (2),
>>>>>
>>>>
>>>
>>>
>>
>>
> 
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/