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

["Alejandro Colomar (man-pages)" <alx.manpages@gmail.com>]

[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.

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),
>>>>
>>>
>>
>>
> 
> 


-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/