[wplug] Linux Programming Book

John Strange john at strangeness.org
Wed Apr 16 15:31:33 EDT 2003 

Well,

I have never done kernel programming or much programming in a high level
language, but from what I can tell you is that the headers files are in
place for correct definition and devices that are defined correct in the
header files.

Changes such as ipfwadm/ipchains/iptables, well the kernel code is
probably quite different for all three.  If you tried to reference
something that works with ip packet filtering under 2.4, it would
probably not work on 2.2 kernels.

If you had the 2.2 header files in place on the machine I would assume
that any specific 2.4 kernel calls you would make would bomb out in the
compile.

On Wed, 2003-04-16 at 15:12, Weber, Larry A wrote:
> Thanks to John, Mike, Dave, Brian, and Eric.  I had fumbled with this
> problem for several days.  With your help, it is up and running in a few
> hours.  WPLUG is an impressive resource.
> 
> Only one question left.  /usr/include/linux contains all the kernel header
> files, but they don't compile.  So what good are they?  Other than to
> confuse me and waste my time do they have any value?
> 
> > -----Original Message-----
> > From:	Dave Neuer [SMTP:mr_fred_smoothie at yahoo.com]
> > Sent:	Wednesday, April 16, 2003 2:56 PM
> > To:	wplug at wplug.org
> > Subject:	RE: [wplug] Linux Programming Book
> > 
> > 
> > --- "Weber, Larry A" <laweber at switch.com> wrote:
> > > What is unclear is why are there so many kernel
> > > header sets?  My Red Hat 8.0
> > > has kernel .h sets at  /usr/include/linux, 
> > > /usr/src/linux-2.4, and
> > > /usr/src/linux-2.4.18-14.  The example program will
> > > not compile with the
> > > first set of .h files but will compile with the
> > > other two.
> > 
> > Well, the first set of headers in this case
> > (/usr/include/*) is probably just the default set that
> > come w/ glibc when compiled for Linux. I.e., you only
> > have headers there which are required to build
> > Posix/Linux applications (NOT kernel modules).
> > 
> > The latter two (if one's not just a symlink to the
> > other) are the full set of kernel header files,
> > including the internal stuff that only in-kernel code
> > needs to see.
> > 
> > > Of course the
> > > resulting .o files will not work.  The modules
> > > install (insmod), with plenty
> > > of warnings, and uninstall (rmmod) but never
> > > execute.
> > 
> > What warnings? Unresolved symbols? Are you sure they
> > get inserted (or are you forcing them w/ insmod -f )?
> > I assume you're doing 'lsmod' to make sure they're
> > there, right?
> > 
> > How are you determining that they didn't execute? Make
> > sure you're looking in the correct logfile for the
> > loglevel you've chosen.
> > 
> > > 
> > > Just ordered a bunch of books on the kernel,  hope
> > > they help.
> > 
> > Jon Corbet's book (Linux Device Drivers?) is good,
> > plus I like "Understanding the Linux Kernel" though it
> > was written for 2.2. Using it w/ 2.4 is still helpful
> > (since the kernel source is available ;-))
> > 
> > Good luck,
> > Dave
> > 
> > > 
> > > 
> > > > -----Original Message-----
> > > > From:	Dave Neuer [SMTP:mr_fred_smoothie at yahoo.com]
> > > > Sent:	Wednesday, April 16, 2003 12:53 PM
> > > > To:	wplug at wplug.org
> > > > Subject:	RE: [wplug] Linux Programming Book
> > > > 
> > > > The problem is more likely that you don't have the
> > > > distro-specific "kernel-headers" package
> > > installed.
> > > > 
> > > > This is something that pisses me off about distros
> > > > (even though since disk space may be limited, it's
> > > > easy to see why -- and even reasonable that they
> > > do
> > > > it): they force you to install "*-dev" packages
> > > > separately from the main software packages, as if
> > > > everyone who installs software on a Linux box is
> > > some
> > > > "dumb user" who will never want to compile an app
> > > > themselves.
> > > > 
> > > > In fact, the opposite is probably still true w/
> > > Linux;
> > > > most people running it will probably have occasion
> > > to
> > > > compile some application by hand from source, and
> > > it's
> > > > not that helpful then to have "libthis" and
> > > "libthat"
> > > > installed w/ out "libthis-dev" and "libthat-dev".
> > > I
> > > > have to admit that of all distros, Debian actually
> > > > seems the worst as far as this goes.
> > > > 
> > > > Of course, kernel hackers and module authors are
> > > > probably more rare than "people who have to
> > > > occasionaly compile some userspace app to get the
> > > > latest-and-greatest feature", but still. What
> > > freakin'
> > > > Linux system shouldn't have kernel headers
> > > installed
> > > > by default in some *default* include search path?
> > > At
> > > > the very least, if you've installed gcc and
> > > binutils
> > > > or other "devlopment" tools, they should install
> > > the
> > > > kernel headers by default.
> > > > 
> > > > Dave
> > > > 
> > > > --- "Weber, Larry A" <laweber at switch.com> wrote:
> > > > > Probably not.  Linux kernels seem to change
> > > pretty
> > > > > fast.  Author claims the
> > > > > application works when compiled on RH71. and
> > > RH7.1. 
> > > > > I am using RH8.0.  I
> > > > > don't know which kernel came with the earlier
> > > revs
> > > > > of RH
> > > > > 
> > > > > > -----Original Message-----
> > > > > > From:	Brian Sammon [SMTP:brians+ at cs.cmu.edu]
> > > > > > Sent:	Wednesday, April 16, 2003 11:31 AM
> > > > > > To:	wplug at wplug.org
> > > > > > Subject:	Re: [wplug] Linux Programming Book
> > > > > > 
> > > > > > > I would like to hear from anyone in WPLUG
> > > who
> > > > > has read the book
> > > > > > "Practical
> > > > > > > Linux Programming: Device Drivers, Embedded
> > > > > Systems, and the Internet"
> > > > > > > Author Ashfaq A. Khan
> > > > > > > 
> > > > > > > I cannot get any of the example programs to
> > > > > compile and would like to
> > > > > > talk
> > > > > > > to anyone who has been successful.
> > > > > > 
> > > > > > One question that springs to mind-- 
> > > > > > Are you using the same kernel revision that
> > > the
> > > > > author based the book on?
> > > > > > 
> > > > > > 
> > > > > >
> > > _______________________________________________
> > > > > > wplug mailing list
> > > > > > wplug at wplug.org
> > > > > > http://www.wplug.org/mailman/listinfo/wplug
> > > > > _______________________________________________
> > > > > wplug mailing list
> > > > > wplug at wplug.org
> > > > > http://www.wplug.org/mailman/listinfo/wplug
> > > > 
> > > > 
> > > > __________________________________________________
> > > > Do you Yahoo!?
> > > > The New Yahoo! Search - Faster. Easier. Bingo
> > > > http://search.yahoo.com
> > > > _______________________________________________
> > > > wplug mailing list
> > > > wplug at wplug.org
> > > > http://www.wplug.org/mailman/listinfo/wplug
> > > _______________________________________________
> > > wplug mailing list
> > > wplug at wplug.org
> > > http://www.wplug.org/mailman/listinfo/wplug
> > 
> > 
> > __________________________________________________
> > Do you Yahoo!?
> > The New Yahoo! Search - Faster. Easier. Bingo
> > http://search.yahoo.com
> > _______________________________________________
> > wplug mailing list
> > wplug at wplug.org
> > http://www.wplug.org/mailman/listinfo/wplug
> _______________________________________________
> wplug mailing list
> wplug at wplug.org
> http://www.wplug.org/mailman/listinfo/wplug

More information about the wplug mailing list