Fellow syslinux fans,
I'm using syslinux on a boot floppy (I'll call this syslinux A) to
invoke an etherboot image (zlilo style) which invokes a tagged NBI
image from my DHCP/TFTP server. The tagged NBI image is created using
mknbi-dos and also uses syslinux (I'll call this syslinux B), a linux
kernel and an initrd file.
It works perfectly if syslinux A has a basic .CFG, e.g.:
PROMPT 0
TIMEOUT 0
DEFAULT alldrvrs.lil
In the above example, 'alldrvrs.lil' is the etherboot image.
I run into trouble if syslinux A is configured to use it's menu
capabilities, e.g.:
DEFAULT menu.c32
PROMPT 0
NOESCAPE 1
MENU TITLE Etherboot Network Boot Disk
TIMEOUT 50
ALLOWOPTIONS 0
LABEL alldrvrs
MENU DEFAULT
MENU LABEL Network boot
KERNEL alldrvrs.lil
In this situation, the etherboot image is invoked just fine and it
successfully TFTP's the tagged NBI image. I see a message regarding
mknbi and then, before syslinux B comes up, the boot fails and I see
this error message:
alldrvrs.lil: attempted DOS system call
I am not an assembly language programmer, but after snooping around the
syslinux source a bit, I have a theory as to why this error manifests
itself only when menu.c32 in loaded.
It looks like COMBOOT sets up an interrupt table so that menu.c32 can
do some basic things. Selecting a menu option triggers 'comapi_run' and
then 'comboot_exit_special' before getting to the non-COMBOOT code. I
think 'comboot_exit_special' should be cleaning up the interrupt table
that was previously set up, no...?
But instead the table gets left behind and eventually gets tickled by
syslinux B; the 'attempted DOS system call' error occurs when an
unsupported function call is made in COMBOOT's 'int21_table'.
Thanks for your consideration,
- Tor
PS - Here's some gory details (hopefully non-relevant)...
versions:
mknbi-1.4.0 # newer seems to have trouble w/ syslinux...?
syslinux-3.08
etherboot-5.4.0
make the tagged NBI image:
TFTP_ARCHIVE=/tftpboot
rm -f /tmp/net-boot.img
drivex='drive x: file="/tmp/net-boot.img"'
( grep -v -i "drive.*x:" ~/.mtoolsrc 2>/dev/null ;
echo "$drivex" ) > ~/.mtoolsrc.new
mv -f ~/.mtoolsrc.new ~/.mtoolsrc
mformat -C -t 80 -s 36 -h 2 x:
mcopy $TFTP_ARCHIVE/pxelinux.cfg/default x:syslinux.cfg
mcopy $TFTP_ARCHIVE/{vmlinuz,miniroot.gz,boot.msg,logo.16} x:
syslinux /tmp/net-boot.img # this is bootable as is...
# make a "tagged" etherboot image from the floppy...
# this will only be bootable inside etherboot...
mknbi-dos --rdbase=0x220000 /tmp/net-boot.img
>$TFTP_ARCHIVE/etherboot.nbi
make the syslinux/etherboot floppy:
# make the etherboot zlilo style image...
export ETHERBOOT_SRC_DIR=/usr/local/src/etherboot-5.4.0
( cd $ETHERBOOT_SRC_DIR/src
make clean
perl -p -i -e 's{-DASK_BOOT=3\s+}{}' Config
DRVS DRIVERS DRVS=" e1000 eepro eepro100 rtl8139
pcnet32 tg3 3c90x 3c509"
DRVS="$DRVS tulip ne wd natsemi via-rhine w89c840 smc9000
cs89x0"
DRVS="$DRVS epic100 sis900"
for d in $DRVS ; do
DRIVERS="${DRIVERS}--${d}"
done ; DRIVERS=`echo ${DRIVERS} | sed s/^--//`
make bin/$DRIVERS.zlilo
cp -vf bin/$DRIVERS.zlilo /tmp/alldrvrs.lil
make clean
)
# now make the syslinux boot floppy
export SYSLINUX_SRC_DIR=/usr/local/src/syslinux-3.08
rm -f /tmp/etherboot.img
drivex='drive x: file="/tmp/etherboot.img"'
( grep -v -i "drive.*x:" ~/.mtoolsrc 2>/dev/null ;
echo "$drivex" ) > ~/.mtoolsrc.new
/bin/mv -f ~/.mtoolsrc.new ~/.mtoolsrc
mformat -C -t 80 -s 18 -h 2 x:
mcopy $SYSLINUX_SRC_DIR/com32/modules/menu.c32 x:
mcopy /tmp/alldrvrs.lil x:
mcopy /tmp/syslinux.cfg x: # as seen above
( cd $SYSLINUX_SRC_DIR
unix/syslinux /tmp/etherboot.img # this is bootable as is...
)
