MINIX 3 Notes

Running inside QEMU with TAP networking

Quick hints:

• TAP networking is preferable to user mode networking since it offers more flexibility – ICMP will work, for example.

• you will need the qemu_pci hack for the NIC to work.

• kqemu didn’t work for me, and probably won’t for you either.

• if [ ! -e /dev/net/tun ]; sudo modprobe tun

GNU/Linux Host System

Invoking

Start script (needs libcap):

#!/bin/sh

IFUP=/home/sky/projects/minix/qemu-ifup

sudo execcap cap_net_admin=ep \
    qemu -no-kqemu -m 256 -boot c \
    -hda TARGET_HDD \
    -net tap,vlan=0,ifname=$TAPDEV,script=$IFUP \
    -net nic

sudo tunctl -d $TAPDEV -f /dev/net/tun

qemu-ifup

#!/bin/sh

set -x

sudo sysctl -w net.ipv4.ip_forward=1

sudo iptables -t nat -F POSTROUTING

sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

sudo ifconfig $1 192.168.2.254

Minix Guest System

qemu_pci=1 and NIC type 4 (dp8390 in /etc/inet.conf)

Routing

add_route -g 192.168.2.254

resolv.conf

cat > /etc/resolv.conf <<EOF
nameserver 192.168.1.1
EOF

Common Problems

• bash fails with something like (here with running the sudo configure script):

  configure: xmalloc: ./parse.y:2716: cannot allocate 64 bytes (0 bytes allocated)
  

  Solution: chmem =512000 $(which bash)

Task Ideas

Trivial

• think about whether distributions make sense
• find name for distro

Janitorial

• merge *_route commands
• add hexadecimal netmask support to ifconfig

Ports

• sudo
• GNU tar
• GNU findutils
• pacman3 and deps (libdownload, libarchive)
• pkill/pgrep
• watch
• checkinstall

API

• semaphores
• pthreads
• mntent.h

Unsorted/Hard

• port a Hurd server
• port a network driver (candidate: sis900)
• dummy network driver
• video card driver abstraction
• ELF support
• drivers segfault when not started as service

Bugfixes

• missing functions:
  • isblank
  • lsearch and companions
  • {get,set}mntent
• GNU df doesn’t really work
• system seems to behave strangely when rootfs gets full

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