On Thursday 12 June 2008 12:14:32 Bill Gatliff wrote:
> Paul Mundt wrote:
> > Yes, that's the easy case. It's things like perl that are the corner
> > cases, and my objection comes from the fact that people think we ought to
> > not have the kernel depend on perl rather than just fixing the package
> > itself. Autoconf/libtool damage is an entirely different problem :-)
>
> At first glance, it seems like checkincludes.pl could be duplicated by
> egrep | uniq | wc vs. egrep | wc. Not quite sure what checkversion.pl is
> trying to do.
There's a difference between "this is a development tool used while modifying
source code" and "this is needed to build".
There are situations where it's ok to have a dependency on X11/qt/gtk, such
as "make xconfig". This is _not_ the same as adding such dependency to "make
modules".
So far, none of the perl dependencies prevent you from building the kernel on
a system that didn't have perl (or didn't have the right version of perl).
> So maybe we could _reduce_ dependency on perl, if there's any advantage to
> gain by doing so. But the kernel build machinery isn't dependent on very
> many other systems (just tcl, bash and gcc-core),
There's no tcl dependency in the build. (Yes, I actually know this.)
Part of my FWL work involves getting the system to rebuild itself under
itself. (The packages you need to make a minimal self-bootstrapping system
are gcc, binutils, make, bash, uClibc, linux, and busybox/toybox). I'm seven
commands away from doing this.
I know this because I made a horrible little wrapper (attached, it really is
sad) which touched a file with the name it was called as and then exec()ed
the actual executable out of another directory. Then I populated a directory
with symlinks to every executable in $PATH (for i in `echo $PATH |
sed 's/:/ /g'`;do for j in `ls $i`; do ln -s $i/$j $j; done; done), and
another directory of similar symlinks to my wrapper. I then ran my build
with that wrapper directory at the start of $PATH and let the wrapper
populate a directory with all the executables that actually got called during
the build. Then I filled up a directory with those executables, tried to run
the build, and figured out why it broke. (The above approach won't find
calls to /bin/bash and a few other things, but it's a good start.)
Most of the point of my ./host-tools.sh wrapper in the FWL build is to
populate a directory with the command line utilities mini-native will have in
it (specifically the busybox/toybox versions, not the ones in the host
system), and set $PATH equal to that directory and only that directory. This
way I know the system will build under itself because that's how it's
building in the first place.
Currently, I need to grab the following out of the host system:
for i in ar as nm cc gcc make ld bzip2 find install od sort diff wget
do
[ ! -f "${HOSTTOOLS}/$i" ] && (ln -s `which $i` "${HOSTTOOLS}/$i" || dienow)
done
The first seven are the needed bits of the host toolchain (you'd think "strip"
would be in there, but it turns out those packages only ever use
$TARGET-strip). The last seven are the ones that are either missing or had
various bugs in the version of busybox I'm using that prevented the build
from working right.
Rob
--
"One of my most productive days was throwing away 1000 lines of code."
- Ken Thompson.
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
char blah[65536];
#define ROOTPATH "/home/landley/firmware/firmware"
int main(int argc, char *argv[], char *env[])
{
char *p, *p2;
int i, fd;
p2 = strrchr(*argv, '/');
if (!p2) p2=*argv;
else p2++;
p=blah + sprintf(blah, "%s ",p2);
for (i=1; i<argc; i++) {
p += sprintf(p, "\"%s\" ",argv[i]);
}
p[-1]='\n';
// Log the command line
fd=open(ROOTPATH "/loggy.txt",O_WRONLY|O_CREAT|O_APPEND,0777);
write(fd, blah, strlen(blah));
close(fd);
// Touch the file that got used.
sprintf(blah,ROOTPATH "/used/%s", p2);
close(open(blah, O_WRONLY|O_CREAT, 0777));
// Hand off control to the real executable
sprintf(blah, ROOTPATH "/handoff/%s", p2);
execve(blah, argv, env);
// Should never happen, means handoff dir is set up wrong.
dprintf(2,"Didn't find %s\n", *argv);
exit(1);
}
