Building an OS image

In this section, there is a functional buildfile that you can use to create an OS image that can be loaded by GRUB without a hard disk or any local storage.

Create the image by typing the following:

$ mkifs -vvv build.txt build.img
$ cp build.img /tftpboot

Here is the buildfile:

Note: In a real buildfile, you can't use a backslash (\) to break a long line into shorter pieces, but we've done that here, just to make the buildfile easier to read.

[virtual=x86,elf +compress] boot = {
    startup-bios

    PATH=/proc/boot:/bin:/usr/bin:/sbin:/usr/sbin: \
    /usr/local/bin:/usr/local/sbin \
    LD_LIBRARY_PATH=/proc/boot: \
    /lib:/usr/lib:/lib/dll  procnto
}

[+script] startup-script = {
    procmgr_symlink ../../proc/boot/libc.so.3 /usr/lib/ldqnx.so.2

    #
    # do magic required to set up PnP and pci bios on x86
    #
    display_msg Do the BIOS magic ...
    seedres
    pci-bios
    waitfor /dev/pci

    #
    # A really good idea is to set hostname and domain
    # before qnet is started
    #
    setconf _CS_HOSTNAME aboyd
    setconf _CS_DOMAIN   ott.qnx.com

    #
    # If you do not set the hostname to something
    # unique before qnet is started, qnet will try
    # to create and set the hostname to a hopefully
    # unique string constructed from the ethernet
    # address, which will look like EAc07f5e
    # which will probably work, but is pretty ugly.
    #

    #
    # start io-pkt, network driver and qnet
    #
    # NB to help debugging, add verbose=1 after -pqnet below
    #
    display_msg Starting io-pkt-v6-hc and speedo driver and qnet ...
    io-pkt-v6-hc -dspeedo -pqnet

    display_msg Waiting for ethernet driver to initialize ...
    waitfor /dev/io-pkt/en0 60

    display_msg Waiting for Qnet to initialize ...
    waitfor /net 60

    #
    # Now that we can fetch executables from the remote server
    # we can run devc-con and ksh, which we do not include in
    # the image, to keep the size down
    #
    # In our example, the server we are booting from
    # has the hostname qpkg and the SAME domain: ott.qnx.com
    #
    # We clean out any old bogus connections to the qpkg server
    # if we have recently rebooted quickly, by fetching a trivial
    # executable which works nicely as a sacrificial lamb
    #
    /net/qpkg/bin/true
    
    #
    # now print out some interesting techie-type information
    #
    display_msg hostname:
    getconf _CS_HOSTNAME
    display_msg domain:
    getconf _CS_DOMAIN
    display_msg uname -a:
    uname -a

    #
    # create some text consoles
    #
    display_msg .
    display_msg Starting 3 text consoles which you can flip
    display_msg between by holding ctrl alt + OR ctrl alt -
    display_msg .
    devc-con -n3
    waitfor /dev/con1

    #
    # start up some command line shells on the text consoles
    #
    reopen /dev/con1
    [+session] TERM=qansi HOME=/ PATH=/bin:/usr/bin:\
    /usr/local/bin:/sbin:/usr/sbin:/usr/local/sbin:\
    /proc/boot ksh &

    reopen /dev/con2
    [+session] TERM=qansi HOME=/ PATH=/bin:/usr/bin:\
    /usr/local/bin:/sbin:/usr/sbin:\
    /usr/local/sbin:/proc/boot ksh &

    reopen /dev/con3
    [+session] TERM=qansi HOME=/ PATH=/bin:\
    /usr/bin:/usr/local/bin:/sbin:/usr/sbin:\
    /usr/local/sbin:/proc/boot ksh &

    #
    # startup script ends here
    #
}

#
# Let's create some links in the virtual file system so that
# applications are fooled into thinking there's a local hard disk
#

#
# Make /tmp point to the shared memory area
#
[type=link] /tmp=/dev/shmem

#
# Redirect console (error) messages to con1
#
[type=link] /dev/console=/dev/con1

#
# Now for the diskless qnet magic.  In this example, we are booting
# using a server which has the hostname qpkg.  Since we do not have
# a hard disk, we will create links to point to the servers disk
#
[type=link] /bin=/net/qpkg/bin
[type=link] /boot=/net/qpkg/boot
[type=link] /etc=/net/qpkg/etc
[type=link] /home=/net/qpkg/home
[type=link] /lib=/net/qpkg/lib
[type=link] /opt=/net/qpkg/opt
[type=link] /pkgs=/net/qpkg/pkgs
[type=link] /root=/net/qpkg/root
[type=link] /sbin=/net/qpkg/sbin
[type=link] /usr=/net/qpkg/usr
[type=link] /var=/net/qpkg/var
[type=link] /x86=/

#
# These are essential shared libraries which must be in the
# image for us to start io-pkt, the ethernet driver and qnet
#
libc.so.2
libc.so
devn-speedo.so
lsm-qnet.so

#
# copy code and data for all following executables
# which will be located in /proc/boot in the image
#
[data=copy]

seedres
pci-bios
setconf
io-pkt-v6-hc
waitfor

# uncomment this for debugging
# getconf