l i n u x - u s e r s - g r o u p - o f - d a v i s
L U G O D
 
Next Meeting:
August 5: Social gathering
Next Installfest:
TBD
Latest News:
Jul. 4: July, August and September: Security, Photography and Programming for Kids
Page last updated:
2010 Jul 09 23:50

The following is an archive of a post made to our 'vox-tech mailing list' by one of its subscribers.

Report this post as spam:

(Enter your email address)
Re: [vox-tech] Permission Denied Error
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [vox-tech] Permission Denied Error



Ownership is not so much the concern as the read-only status of the file is. Tar maintains rwx status more consistently than ownership.

"Matthew Holland" <mdholland@ucdavis.edu> wrote:

>It seems pretty clear to me from the OP's further clarifications that
>this is a header file that belongs to a third party application, and
>the effects of editing the header file in question are known to the
>poster.  The OP's lack of familiarity with UNIX comes through, and I
>think this is rousing everyone's protective instincts.  Fine, but this
>all probably resulted from untarring the source code with sudo in the
>first place, so I think we can all just calm down with the warnings.
>
>I should add that I screwed up the chown command in my first response.
> It should be "chown username file" instead of "chown file username."
>Sorry for any confusion.
>
>I would recommend the the OP that if you're going to be using a Mac
>for this sort of thing, you do some reading on general UNIX use and
>administration.  And learn to read man pages, if you don't know
>already.  All will become clear in good time.
>
>Matt
>
>On Fri, Jul 9, 2010 at 10:59 AM, Bill Kendrick <nbs@sonic.net> wrote:
>> On Thu, Jul 08, 2010 at 10:19:00PM -0700, Jeff Newmiller wrote:
>>> Unless you have the full source code and are familiar enough with it
>>> to insure that it doesn't have hidden dependencies on those constants,
>>> and are recompiling the full source code, you should still be wary of
>>> changing read-only headers.
>>
>> Indeed.
>>
>> Furthermore, a more proper way of altering constants for your own
>> app's purpose would be to redefine them in your source, rather than
>> alter the library's header file.
>>
>> e.g.:
>>
>>  #include <some_library_header.h>
>>
>>  #if defined(SOMECONST)
>>    #undef SOMECONST
>>  #end
>>
>>  /* Override some_library_header.h's SOMECONST with my own number */
>>  #define SOMECONST 1234
>>
>>
>> Obviously, this changed constant will only be visible to the file(s)
>> that see the above C preprocessor commands.
>>
>> But do keep in mind, as explained earlier, even if you change some
>> #define's _in the system-wide header file_ (e.g., if I go in and
>> screw around with "/usr/include/stdio.h"), those changes will only
>> affect:
>>
>>  * programs compiled with that header
>>  * and compiled AFTER I edited it
>>
>> The "stdio" library itself, and any applications which were compiled
>> against the "stdio.h" header prior to my edits, will REMAIN UNCHANGED.
>>
>>
>> I'm throwing these caveats in here because I think we still don't
>> know exactly what you're trying to accomplish. :)  Based on the vague
>> requirement of "need to change numbers in a header file", what you're
>> trying to do could range from trivial to impossible to downright
>> dangerous. :)
>>
>>
>>
>> -bill!
>> _______________________________________________
>> vox-tech mailing list
>> vox-tech@lists.lugod.org
>> http://lists.lugod.org/mailman/listinfo/vox-tech
>>
>_______________________________________________
>vox-tech mailing list
>vox-tech@lists.lugod.org
>http://lists.lugod.org/mailman/listinfo/vox-tech

---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil@dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
                                      Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k
---------------------------------------------------------------------------
Sent from my phone. Please excuse my brevity.
_______________________________________________
vox-tech mailing list
vox-tech@lists.lugod.org
http://lists.lugod.org/mailman/listinfo/vox-tech


LinkedIn
LUGOD Group on LinkedIn
Sign up for LUGOD event announcements
Your email address:
facebook
LUGOD Group on Facebook
'Like' LUGOD on Facebook:

Hosting provided by:
Sunset Systems
Sunset Systems offers preconfigured Linux systems, remote system administration and custom software development.

LUGOD: Linux Users' Group of Davis
PO Box 2082, Davis, CA 95617
Contact Us

LUGOD is a 501(c)7 non-profit organization
based in Davis, California
and serving the Sacramento area.
"Linux" is a trademark of Linus Torvalds.

Sponsored in part by:
Appahost Applications
For a significant contribution towards our projector, and a generous donation to allow us to continue meeting at the Davis Library.